stb.h

/* stb-2.02 - Sean's Tool Box -- public domain -- http://nothings.org/stb.h
          no warranty is offered or implied; use this code at your own risk

   This is a single header file with a bunch of useful utilities
   for getting stuff done in C/C++.

   Email bug reports, feature requests, etc. to 'sean' at the same site.


   Documentation: http://nothings.org/stb/stb_h.html
   Unit tests:    http://nothings.org/stb/stb.c


 ============================================================================
   You MUST                                                                  
                                                                             
      #define STB_DEFINE                                                     
                                                                             
   in EXACTLY _one_ C or C++ file that includes this header, BEFORE the
   include, like this:                                                                
                                                                             
      #define STB_DEFINE                                                     
      #include "stb.h"
      
   All other files should just #include "stb.h" without the #define.
 ============================================================================


Version History

   2.02   remove integrated documentation
   2.01   integrate various fixes; stb_force_uniprocessor
   2.00   revised stb_dupe to use multiple hashes
   1.99   stb_charcmp
   1.98   stb_arr_deleten, stb_arr_insertn
   1.97   fix stb_newell_normal()
   1.96   stb_hash_number()
   1.95   hack stb__rec_max; clean up recursion code to use new functions
   1.94   stb_dirtree; rename stb_extra to stb_ptrmap
   1.93   stb_sem_new() API cleanup (no blockflag-starts blocked; use 'extra')
   1.92   stb_threadqueue--multi reader/writer queue, fixed size or resizeable
   1.91   stb_bgio_* for reading disk asynchronously
   1.90   stb_mutex uses CRITICAL_REGION; new stb_sync primitive for thread
          joining; workqueue supports stb_sync instead of stb_semaphore
   1.89   support ';' in constant-string wildcards; stb_mutex wrapper (can
          implement with EnterCriticalRegion eventually)
   1.88   portable threading API (only for win32 so far); worker thread queue
   1.87   fix wildcard handling in stb_readdir_recursive
   1.86   support ';' in wildcards
   1.85   make stb_regex work with non-constant strings;
               beginnings of stb_introspect()
   1.84   (forgot to make notes)
   1.83   whoops, stb_keep_if_different wasn't deleting the temp file
   1.82   bring back stb_compress from stb_file.h for cmirror
   1.81   various bugfixes, STB_FASTMALLOC_INIT inits FASTMALLOC in release
   1.80   stb_readdir returns utf8; write own utf8-utf16 because lib was wrong
   1.79   stb_write
   1.78   calloc() support for malloc wrapper, STB_FASTMALLOC
   1.77   STB_FASTMALLOC
   1.76   STB_STUA - Lua-like language; (stb_image, stb_csample, stb_bilinear)
   1.75   alloc/free array of blocks; stb_hheap bug; a few stb_ps_ funcs;
          hash*getkey, hash*copy; stb_bitset; stb_strnicmp; bugfix stb_bst
   1.74   stb_replaceinplace; use stdlib C function to convert utf8 to UTF-16
   1.73   fix performance bug & leak in stb_ischar (C++ port lost a 'static')
   1.72   remove stb_block, stb_block_manager, stb_decompress (to stb_file.h)
   1.71   stb_trimwhite, stb_tokens_nested, etc.
   1.70   back out 1.69 because it might problemize mixed builds; stb_filec()
   1.69   (stb_file returns 'char *' in C++)
   1.68   add a special 'tree root' data type for stb_bst; stb_arr_end
   1.67   full C++ port. (stb_block_manager)
   1.66   stb_newell_normal
   1.65   stb_lex_item_wild -- allow wildcard items which MUST match entirely
   1.64   stb_data
   1.63   stb_log_name
   1.62   stb_define_sort; C++ cleanup
   1.61   stb_hash_fast -- Paul Hsieh's hash function (beats Bob Jenkins'?)
   1.60   stb_delete_directory_recursive
   1.59   stb_readdir_recursive
   1.58   stb_bst variant with parent pointer for O(1) iteration, not O(log N)
   1.57   replace LCG random with Mersenne Twister (found a public domain one)
   1.56   stb_perfect_hash, stb_ischar, stb_regex
   1.55   new stb_bst API allows multiple BSTs per node (e.g. secondary keys)
   1.54   bugfix: stb_define_hash, stb_wildmatch, regexp
   1.53   stb_define_hash; recoded stb_extra, stb_sdict use it
   1.52   stb_rand_define, stb_bst, stb_reverse
   1.51   fix 'stb_arr_setlen(NULL, 0)'
   1.50   stb_wordwrap
   1.49   minor improvements to enable the scripting language
   1.48   better approach for stb_arr using stb_malloc; more invasive, clearer
   1.47   stb_lex (lexes stb.h at 1.5ML/s on 3Ghz P4; 60/70% of optimal/flex)
   1.46   stb_wrapper_*, STB_MALLOC_WRAPPER
   1.45   lightly tested DFA acceleration of regexp searching
   1.44   wildcard matching & searching; regexp matching & searching
   1.43   stb_temp
   1.42   allow stb_arr to use stb_malloc/realloc; note this is global
   1.41   make it compile in C++; (disable stb_arr in C++)
   1.40   stb_dupe tweak; stb_swap; stb_substr
   1.39   stb_dupe; improve stb_file_max to be less stupid
   1.38   stb_sha1_file: generate sha1 for file, even > 4GB
   1.37   stb_file_max; partial support for utf8 filenames in Windows
   1.36   remove STB__NO_PREFIX - poor interaction with IDE, not worth it
          streamline stb_arr to make it separately publishable
   1.35   bugfixes for stb_sdict, stb_malloc(0), stristr
   1.34   (streaming interfaces for stb_compress)
   1.33   stb_alloc; bug in stb_getopt; remove stb_overflow
   1.32   (stb_compress returns, smaller&faster; encode window & 64-bit len)
   1.31   stb_prefix_count
   1.30   (STB__NO_PREFIX - remove stb_ prefixes for personal projects)
   1.29   stb_fput_varlen64, etc.
   1.28   stb_sha1
   1.27   ?
   1.26   stb_extra
   1.25   ?
   1.24   stb_copyfile
   1.23   stb_readdir
   1.22   ?
   1.21   ?
   1.20   ?
   1.19   ?
   1.18   ?
   1.17   ?
   1.16   ?
   1.15   stb_fixpath, stb_splitpath, stb_strchr2
   1.14   stb_arr
   1.13   ?stb, stb_log, stb_fatal
   1.12   ?stb_hash2
   1.11   miniML
   1.10   stb_crc32, stb_adler32
   1.09   stb_sdict
   1.08   stb_bitreverse, stb_ispow2, stb_big32
          stb_fopen, stb_fput_varlen, stb_fput_ranged
          stb_fcmp, stb_feq
   1.07   (stb_encompress)
   1.06   stb_compress
   1.05   stb_tokens, (stb_hheap)
   1.04   stb_rand
   1.03   ?(s-strings)
   1.02   ?stb_filelen, stb_tokens
   1.01   stb_tolower
   1.00   stb_hash, stb_intcmp
          stb_file, stb_stringfile, stb_fgets
          stb_prefix, stb_strlower, stb_strtok
          stb_image
          (stb_array), (stb_arena)

Parenthesized items have since been removed.
*/

#ifndef STB__INCLUDE_STB_H
#define STB__INCLUDE_STB_H

#include <stdlib.h>     // stdlib could have min/max
#include <stdio.h>      // need FILE
#include <string.h>     // stb_define_hash needs memcpy/memset
#include <time.h>       // stb_dirtree

#ifdef STB_PERSONAL
   typedef int Bool;
   #define False 0
   #define True 1
#endif

#ifdef STB_MALLOC_WRAPPER_PAGED
   #define STB_MALLOC_WRAPPER_DEBUG
#endif
#ifdef STB_MALLOC_WRAPPER_DEBUG
   #define STB_MALLOC_WRAPPER
#endif
#ifdef STB_MALLOC_WRAPPER_FASTMALLOC
   #define STB_FASTMALLOC
   #define STB_MALLOC_WRAPPER
#endif

#ifdef STB_FASTMALLOC
   #ifndef _WIN32
      #undef STB_FASTMALLOC
   #endif
#endif

#ifdef STB_DEFINE
   #include <assert.h>
   #include <stdarg.h>
   #include <stddef.h>
   #include <ctype.h>
   #include <math.h>
   #ifndef _WIN32
   #include <unistd.h>
   #else
   #include <io.h>      // _mktemp
   #include <direct.h>  // _rmdir
   #endif
   #include <sys/types.h> // stat()/_stat()
   #include <sys/stat.h>  // stat()/_stat()
#endif

#define stb_min(a,b)   ((a) < (b) ? (a) : (b))
#define stb_max(a,b)   ((a) > (b) ? (a) : (b))

#ifndef STB_ONLY
   #if !defined(__cplusplus) && !defined(min) && !defined(max)
     #define min(x,y) stb_min(x,y)
     #define max(x,y) stb_max(x,y)
   #endif

   #ifndef M_PI
     #define M_PI  3.14159265358979323846f
   #endif
   
   #ifndef TRUE
     #define TRUE  1
     #define FALSE 0
   #endif
   
   #ifndef deg2rad
   #define deg2rad(a)  ((a)*(M_PI/180))
   #endif
   #ifndef rad2deg
   #define rad2deg(a)  ((a)*(180/M_PI))
   #endif
   
   #ifndef swap
   #ifndef __cplusplus
   #define swap(TYPE,a,b)  \
               do { TYPE stb__t; stb__t = (a); (a) = (b); (b) = stb__t; } while (0)
   #endif              
   #endif
    
   typedef unsigned char  uint8 ;
   typedef   signed char   int8 ;
   typedef unsigned short uint16;
   typedef   signed short  int16;
  #if defined(STB_USE_LONG_FOR_32_BIT_INT) || defined(STB_LONG32)
   typedef unsigned long  uint32;
   typedef   signed long   int32;
  #else
   typedef unsigned int   uint32;
   typedef   signed int    int32;
  #endif

   typedef unsigned char  uchar ;
   typedef unsigned short ushort;
   typedef unsigned int   uint  ;
   typedef unsigned long  ulong ;

   // produce compile errors if the sizes aren't right
   typedef char stb__testsize16[sizeof(int16)==2];
   typedef char stb__testsize32[sizeof(int32)==4];
#endif

// if we're STB_ONLY, can't rely on uint32 or even uint, so all the
// variables we'll use herein need typenames prefixed with 'stb':
typedef unsigned char stb_uchar;
typedef unsigned char stb_uint8;
typedef unsigned int  stb_uint;
typedef unsigned short stb_uint16;
typedef          short stb_int16;
typedef   signed char  stb_int8;
#if defined(STB_USE_LONG_FOR_32_BIT_INT) || defined(STB_LONG32)
  typedef unsigned long  stb_uint32;
  typedef          long  stb_int32;
#else
  typedef unsigned int   stb_uint32;
  typedef          int   stb_int32;
#endif
typedef char stb__testsize2_16[sizeof(stb_uint16)==2];
typedef char stb__testsize2_32[sizeof(stb_uint32)==4];

#ifdef __cplusplus
   #define STB_EXTERN   extern "C"
#else
   #define STB_EXTERN   extern
#endif

// check for well-known debug defines
#if defined(DEBUG) || defined(_DEBUG) || defined(DBG)
   #ifndef NDEBUG
      #define STB_DEBUG
   #endif
#endif

#ifdef STB_DEBUG
   #include <assert.h>
#endif


STB_EXTERN void stb_wrapper_malloc(void *newp, int sz, char *file, int line);
STB_EXTERN void stb_wrapper_free(void *oldp, char *file, int line);
STB_EXTERN void stb_wrapper_realloc(void *oldp, void *newp, int sz, char *file, int line);
STB_EXTERN void stb_wrapper_calloc(size_t num, size_t sz, char *file, int line);
STB_EXTERN void stb_wrapper_listall(void (*func)(void *ptr, int sz, char *file, int line));
STB_EXTERN void stb_wrapper_dump(char *filename);
STB_EXTERN int stb_wrapper_allocsize(void *oldp);
STB_EXTERN void stb_wrapper_check(void *oldp);

#ifdef STB_DEFINE
// this is a special function used inside malloc wrapper
// to do allocations that aren't tracked (to avoid
// reentrancy). Of course if someone _else_ wraps realloc,
// this breaks, but if they're doing that AND the malloc
// wrapper they need to explicitly check for reentrancy.
//
// only define realloc_raw() and we do realloc(NULL,sz)
// for malloc() and realloc(p,0) for free().
static void * stb__realloc_raw(void *p, int sz)
{
   if (p == NULL) return malloc(sz);
   if (sz == 0)   { free(p); return NULL; }
   return realloc(p,sz);
}
#endif

#ifdef _WIN32
STB_EXTERN void * stb_smalloc(size_t sz);
STB_EXTERN void   stb_sfree(void *p);
STB_EXTERN void * stb_srealloc(void *p, size_t sz);
STB_EXTERN void * stb_scalloc(size_t n, size_t sz);
STB_EXTERN char * stb_sstrdup(char *s);
#endif

#ifdef STB_FASTMALLOC
#define malloc  stb_smalloc
#define free    stb_sfree
#define realloc stb_srealloc
#define strdup  stb_sstrdup
#define calloc  stb_scalloc
#endif

#ifndef STB_MALLOC_ALLCHECK
   #define stb__check(p)  1
#else
   #ifndef STB_MALLOC_WRAPPER
      #error STB_MALLOC_ALLCHECK requires STB_MALLOC_WRAPPER
   #else
      #define stb__check(p) stb_mcheck(p)
   #endif
#endif

#ifdef STB_MALLOC_WRAPPER
   STB_EXTERN void * stb__malloc(int, char *, int);
   STB_EXTERN void * stb__realloc(void *, int, char *, int);
   STB_EXTERN void * stb__calloc(size_t n, size_t s, char *, int);
   STB_EXTERN void   stb__free(void *, char *file, int);
   STB_EXTERN char * stb__strdup(char *s, char *file, int);
   STB_EXTERN void   stb_malloc_checkall(void);
   STB_EXTERN void   stb_malloc_check_counter(int init_delay, int rep_delay);
   #ifndef STB_MALLOC_WRAPPER_DEBUG
      #define stb_mcheck(p) 1
   #else
      STB_EXTERN int   stb_mcheck(void *);
   #endif


   #ifdef STB_DEFINE

   #ifdef STB_MALLOC_WRAPPER_DEBUG
      #define STB__PAD   32
      #define STB__BIAS  16
      #define STB__SIG   0x51b01234
      #define STB__FIXSIZE(sz)  (((sz+3) & ~3) + STB__PAD)
      #define STB__ptr(x,y)   ((char *) (x) + (y))
   #else
      #define STB__ptr(x,y)   (x)
      #define STB__FIXSIZE(sz)  (sz)
   #endif

   #ifdef STB_MALLOC_WRAPPER_DEBUG
   int stb_mcheck(void *p)
   {
      unsigned int sz;
      if (p == NULL) return 1;
      p = ((char *) p) - STB__BIAS;
      sz = * (unsigned int *) p;
      assert(* (unsigned int *) STB__ptr(p,4) == STB__SIG);
      assert(* (unsigned int *) STB__ptr(p,8) == STB__SIG);
      assert(* (unsigned int *) STB__ptr(p,12) == STB__SIG);
      assert(* (unsigned int *) STB__ptr(p,sz-4) == STB__SIG+1);
      assert(* (unsigned int *) STB__ptr(p,sz-8) == STB__SIG+1);
      assert(* (unsigned int *) STB__ptr(p,sz-12) == STB__SIG+1);
      assert(* (unsigned int *) STB__ptr(p,sz-16) == STB__SIG+1);
      stb_wrapper_check(STB__ptr(p, STB__BIAS));
      return 1;
   }

   static void stb__check2(void *p, int sz, char *file, int line)
   {
      stb_mcheck(p);
   }

   void stb_malloc_checkall(void)
   {
      stb_wrapper_listall(stb__check2);
   }
   #else
   void stb_malloc_checkall(void) { }
   #endif

   static int stb__malloc_wait=(1 << 30), stb__malloc_next_wait = (1 << 30), stb__malloc_iter;
   void stb_malloc_check_counter(int init_delay, int rep_delay)
   {
      stb__malloc_wait = init_delay;
      stb__malloc_next_wait = rep_delay;
   }

   void stb_mcheck_all(void)
   {
      #ifdef STB_MALLOC_WRAPPER_DEBUG
      ++stb__malloc_iter;
      if (--stb__malloc_wait <= 0) {
         stb_malloc_checkall();
         stb__malloc_wait = stb__malloc_next_wait;
      }
      #endif
   }

   #ifdef STB_MALLOC_WRAPPER_PAGED
   #define STB__WINDOWS_PAGE (1 << 12)
   #ifndef _WINDOWS_
   STB_EXTERN __declspec(dllimport) void * __stdcall VirtualAlloc(void *p, unsigned long size, unsigned long type, unsigned long protect);
   STB_EXTERN __declspec(dllimport) int   __stdcall VirtualFree(void *p, unsigned long size, unsigned long freetype);
   #endif
   #endif

   static void *stb__malloc_final(int sz)
   {
      #ifdef STB_MALLOC_WRAPPER_PAGED
      int aligned = (sz + STB__WINDOWS_PAGE - 1) & ~(STB__WINDOWS_PAGE-1);
      char *p = VirtualAlloc(NULL, aligned + STB__WINDOWS_PAGE, 0x2000, 0x04); // RESERVE, READWRITE
      if (p == NULL) return p;
      VirtualAlloc(p, aligned,   0x1000, 0x04); // COMMIT, READWRITE
      return p;
      #else
      return malloc(sz);
      #endif
   }

   static void stb__free_final(void *p)
   {
      #ifdef STB_MALLOC_WRAPPER_PAGED
      VirtualFree(p, 0, 0x8000); // RELEASE
      #else
      free(p);
      #endif
   }

   int stb__malloc_failure;
   static void *stb__realloc_final(void *p, int sz, int old_sz)
   {
      #ifdef STB_MALLOC_WRAPPER_PAGED
      void *q = stb__malloc_final(sz);
      if (q == NULL)
          return ++stb__malloc_failure, q;
      // @TODO: deal with p being smaller!
      memcpy(q, p, sz < old_sz ? sz : old_sz);
      stb__free_final(p);
      return q;
      #else
      return realloc(p,sz);
      #endif
   }

   void stb__free(void *p, char *file, int line)
   {
      stb_mcheck_all();
      if (!p) return;
      #ifdef STB_MALLOC_WRAPPER_DEBUG
      stb_mcheck(p);
      #endif
      stb_wrapper_free(p,file,line);
      #ifdef STB_MALLOC_WRAPPER_DEBUG
         p = STB__ptr(p,-STB__BIAS);
         * (unsigned int *) STB__ptr(p,0) = 0xdeadbeef;
         * (unsigned int *) STB__ptr(p,4) = 0xdeadbeef;
         * (unsigned int *) STB__ptr(p,8) = 0xdeadbeef;
         * (unsigned int *) STB__ptr(p,12) = 0xdeadbeef;
      #endif
      stb__free_final(p);
   }

   void * stb__malloc(int sz, char *file, int line)
   {
      void *p;
      stb_mcheck_all();
      if (sz == 0) return NULL;
      if (stb__malloc_iter == 12741)
         sz = sz;
      p = stb__malloc_final(STB__FIXSIZE(sz));
      if (p == NULL) p = stb__malloc_final(STB__FIXSIZE(sz));
      if (p == NULL) p = stb__malloc_final(STB__FIXSIZE(sz));
      if (p == NULL) {
         ++stb__malloc_failure;
         #ifdef STB_MALLOC_WRAPPER_DEBUG
         stb_malloc_checkall();
         #endif
         return p;
      }
      #ifdef STB_MALLOC_WRAPPER_DEBUG
      * (int *) STB__ptr(p,0) = STB__FIXSIZE(sz);
      * (unsigned int *) STB__ptr(p,4) = STB__SIG;
      * (unsigned int *) STB__ptr(p,8) = STB__SIG;
      * (unsigned int *) STB__ptr(p,12) = STB__SIG;
      * (unsigned int *) STB__ptr(p,STB__FIXSIZE(sz)-4) = STB__SIG+1;
      * (unsigned int *) STB__ptr(p,STB__FIXSIZE(sz)-8) = STB__SIG+1;
      * (unsigned int *) STB__ptr(p,STB__FIXSIZE(sz)-12) = STB__SIG+1;
      * (unsigned int *) STB__ptr(p,STB__FIXSIZE(sz)-16) = STB__SIG+1;
      p = STB__ptr(p, STB__BIAS);
      #endif
      stb_wrapper_malloc(p,sz,file,line);
      return p;
   }

   void * stb__realloc(void *p, int sz, char *file, int line)
   {
      void *q;

      stb_mcheck_all();
      if (p == NULL) return stb__malloc(sz,file,line);
      if (sz == 0  ) { stb__free(p,file,line); return NULL; }

      #ifdef STB_MALLOC_WRAPPER_DEBUG
         stb_mcheck(p);
         p = STB__ptr(p,-STB__BIAS);
      #endif
      #ifdef STB_MALLOC_WRAPPER_PAGED
      {
         int n = stb_wrapper_allocsize(STB__ptr(p,STB__BIAS));
         if (!n)
            stb_wrapper_check(STB__ptr(p,STB__BIAS));
         q = stb__realloc_final(p, STB__FIXSIZE(sz), STB__FIXSIZE(n));
      }
      #else
      q = realloc(p, STB__FIXSIZE(sz));
      #endif
      if (q == NULL)
         return ++stb__malloc_failure, q;
      #ifdef STB_MALLOC_WRAPPER_DEBUG
      * (int *) STB__ptr(q,0) = STB__FIXSIZE(sz);
      * (unsigned int *) STB__ptr(q,4) = STB__SIG;
      * (unsigned int *) STB__ptr(q,8) = STB__SIG;
      * (unsigned int *) STB__ptr(q,12) = STB__SIG;
      * (unsigned int *) STB__ptr(q,STB__FIXSIZE(sz)-4) = STB__SIG+1;
      * (unsigned int *) STB__ptr(q,STB__FIXSIZE(sz)-8) = STB__SIG+1;
      * (unsigned int *) STB__ptr(q,STB__FIXSIZE(sz)-12) = STB__SIG+1;
      * (unsigned int *) STB__ptr(q,STB__FIXSIZE(sz)-16) = STB__SIG+1;

      q = STB__ptr(q, STB__BIAS);
      p = STB__ptr(p, STB__BIAS);
      #endif
      stb_wrapper_realloc(p,q,sz,file,line);
      return q;
   }

   STB_EXTERN int stb_log2_ceil(unsigned int);
   static void *stb__calloc(size_t n, size_t sz, char *file, int line)
   {
      void *q;
      stb_mcheck_all();
      if (n == 0 || sz == 0) return NULL;
      if (stb_log2_ceil(n) + stb_log2_ceil(sz) >= 32) return NULL;
      q = stb__malloc(n*sz, file, line);
      if (q) memset(q, 0, n*sz);
      return q;
   }

   char * stb__strdup(char *s, char *file, int line)
   {
      char *p;
      stb_mcheck_all();
      p = stb__malloc(strlen(s)+1, file, line);
      if (!p) return p;
      strcpy(p, s);
      return p;
   }
   #endif // STB_DEFINE

   #ifdef STB_FASTMALLOC
   #undef malloc
   #undef realloc
   #undef free
   #undef strdup
   #undef calloc
   #endif

   // include everything that might define these, BEFORE making macros
   #include <stdlib.h>
   #include <string.h>
   #include <malloc.h>

   #define malloc(s)      stb__malloc (  s, __FILE__, __LINE__)
   #define realloc(p,s)   stb__realloc(p,s, __FILE__, __LINE__)
   #define calloc(n,s)    stb__calloc (n,s, __FILE__, __LINE__)
   #define free(p)        stb__free   (p,   __FILE__, __LINE__)
   #define strdup(p)      stb__strdup (p,   __FILE__, __LINE__)

#endif

//////////////////////////////////////////////////////////////////////////////
//
//                         Windows UTF8 filename handling
//
// Windows stupidly treats 8-bit filenames as some dopey code page,
// rather than utf-8. If we want to use utf8 filenames, we have to
// convert them to WCHAR explicitly and call WCHAR versions of the
// file functions. So, ok, we do.


#ifdef _WIN32
   #define stb__fopen(x,y)    _wfopen(stb__from_utf8(x), stb__from_utf8_alt(y))
   #define stb__windows(x,y)  x
#else
   #define stb__fopen(x,y)    fopen(x,y)
   #define stb__windows(x,y)  y
#endif


typedef unsigned short stb__wchar;

STB_EXTERN stb__wchar * stb_from_utf8(stb__wchar *buffer, char *str, int n);
STB_EXTERN char       * stb_to_utf8  (char *buffer, stb__wchar *str, int n);

STB_EXTERN stb__wchar *stb__from_utf8(char *str);
STB_EXTERN stb__wchar *stb__from_utf8_alt(char *str);
STB_EXTERN char *stb__to_utf8(stb__wchar *str);


#ifdef STB_DEFINE
stb__wchar * stb_from_utf8(stb__wchar *buffer, char *str, int n)
{
   uint32 c;
   int i=0;
   --n;
   while (*str) {
      if (i >= n)
         return NULL;
      if (!(*str & 0x80))
         buffer[i++] = *str++;
      else if ((*str & 0xe0) == 0xc0) {
         c = (*str++ & 0x1f) << 6;
         if ((*str & 0xc0) != 0x80) return NULL;
         buffer[i++] = c + (*str++ & 0x3f);
      } else if ((*str & 0xf0) == 0xe0) {
         c = (*str++ & 0x0f) << 12;
         if ((*str & 0xc0) != 0x80) return NULL;
         c += (*str++ & 0x3f) << 6;
         if ((*str & 0xc0) != 0x80) return NULL;
         buffer[i++] = c + (*str++ & 0x3f);
      } else if ((*str & 0xf8) == 0xf0) {
         c = (*str++ & 0x07) << 18;
         if ((*str & 0xc0) != 0x80) return NULL;
         c += (*str++ & 0x3f) << 12;
         if ((*str & 0xc0) != 0x80) return NULL;
         c += (*str++ & 0x3f) << 6;
         if ((*str & 0xc0) != 0x80) return NULL;
         c += (*str++ & 0x3f);
         // surrogate pair values are invalid
         if ((c & 0xFFFFF800) == 0xD800) return NULL;
         if (c >= 0x10000) {
            c -= 0x10000;
            if (i + 2 > n) return NULL;
            buffer[i++] = 0xD800 | (0x3ff & (c >> 10));
            buffer[i++] = 0xDC00 | (0x3ff & (c      ));
         }
      } else
         return NULL;
   }
   buffer[i] = 0;
   return buffer;
}

char * stb_to_utf8(char *buffer, stb__wchar *str, int n)
{
   int i=0;
   --n;
   while (*str) {
      if (*str < 0x80) {
         if (i+1 > n) return NULL;
         buffer[i++] = (char) *str++;
      } else if (*str < 0x800) {
         if (i+2 > n) return NULL;
         buffer[i++] = 0xc0 + (*str >> 6);
         buffer[i++] = 0x80 + (*str & 0x3f);
         str += 1;
      } else if (*str >= 0xd800 && *str < 0xdc00) {
         uint32 c;
         if (i+4 > n) return NULL;
         c = ((str[0] - 0xd800) << 10) + ((str[1]) - 0xdc00) + 0x10000;
         buffer[i++] = 0xf0 + (c >> 18);
         buffer[i++] = 0x80 + ((c >> 12) & 0x3f);
         buffer[i++] = 0x80 + ((c >>  6) & 0x3f);
         buffer[i++] = 0x80 + ((c      ) & 0x3f);
         str += 2;
      } else if (*str >= 0xdc00 && *str < 0xe000) {
         return NULL;
      } else {
         if (i+3 > n) return NULL;
         buffer[i++] = 0xe0 + (*str >> 12);
         buffer[i++] = 0x80 + ((*str >> 6) & 0x3f);
         buffer[i++] = 0x80 + ((*str     ) & 0x3f);
         str += 1;
      }
   }
   buffer[i] = 0;
   return buffer;
}

stb__wchar *stb__from_utf8(char *str)
{
   static stb__wchar buffer[4096];
   return stb_from_utf8(buffer, str, 4096);
}

stb__wchar *stb__from_utf8_alt(char *str)
{
   static stb__wchar buffer[64];
   return stb_from_utf8(buffer, str, 64);
}

char *stb__to_utf8(stb__wchar *str)
{
   static char buffer[4096];
   return stb_to_utf8(buffer, str, 4096);
}

#endif

//////////////////////////////////////////////////////////////////////////////
//
//                         Miscellany
//

STB_EXTERN void stb_fatal(char *fmt, ...);
STB_EXTERN void stb_(char *fmt, ...);
STB_EXTERN void stb_log(int active);
STB_EXTERN void stb_log_fileline(int active);
STB_EXTERN void stb_log_name(char *filename);

STB_EXTERN void stb_swap(void *p, void *q, size_t sz);
STB_EXTERN void *stb_copy(void *p, size_t sz);
STB_EXTERN void stb_pointer_array_free(void **p, int len);
STB_EXTERN void **stb_array_block_alloc(int count, int blocksize);

#define stb_arrcount(x)   (sizeof(x)/sizeof((x)[0]))


STB_EXTERN int  stb__record_fileline(char *f, int n);

#ifdef STB_DEFINE

static char *stb__file;
static int   stb__line;

int  stb__record_fileline(char *f, int n)
{
   stb__file = f;
   stb__line = n;
   return 0;
}

void stb_fatal(char *s, ...)
{
   va_list a;
   if (stb__file)
      fprintf(stderr, "[%s:%d] ", stb__file, stb__line);
   va_start(a,s);
   fputs("Fatal error: ", stderr);
   vfprintf(stderr, s, a);
   va_end(a);
   fputs("\n", stderr);
   #ifdef _WIN32
   #ifdef STB_DEBUG
   __asm int 3;   // trap to debugger!
   #endif
   #endif
   exit(1);
}

static int stb__log_active=1, stb__log_fileline=1;

void stb_log(int active)
{
   stb__log_active = active;
}

void stb_log_fileline(int active)
{
   stb__log_fileline = active;
}

#ifdef STB_NO_STB_STRINGS
char *stb__log_filename = "temp.log";
#else
char *stb__log_filename = "stb.log";
#endif

void stb_log_name(char *s)
{
   stb__log_filename = s;
}

void stb_(char *s, ...)
{
   if (stb__log_active) {
      FILE *f = fopen(stb__log_filename, "a");
      if (f) {
         va_list a;
         if (stb__log_fileline && stb__file)
            fprintf(f, "[%s:%4d] ", stb__file, stb__line);
         va_start(a,s);
         vfprintf(f, s, a);
         va_end(a);
         fputs("\n", f);
         fclose(f);
      }
   }
}


typedef struct { char d[4]; } stb__4;
typedef struct { char d[8]; } stb__8;

// optimize the small cases, though you shouldn't be calling this for those!
void stb_swap(void *p, void *q, size_t sz)
{
   char buffer[256];
   if (p == q) return;
   if (sz == 4) {
      stb__4 temp    = * ( stb__4 *) p;
      * (stb__4 *) p = * ( stb__4 *) q;
      * (stb__4 *) q = temp;
      return;
   } else if (sz == 8) {
      stb__8 temp    = * ( stb__8 *) p;
      * (stb__8 *) p = * ( stb__8 *) q;
      * (stb__8 *) q = temp;
      return;
   }

   while (sz > sizeof(buffer)) {
      stb_swap(p, q, sizeof(buffer));
      p = (char *) p + sizeof(buffer);
      q = (char *) q + sizeof(buffer);
      sz -= sizeof(buffer);
   }

   memcpy(buffer, p     , sz);
   memcpy(p     , q     , sz);
   memcpy(q     , buffer, sz);
}

void *stb_copy(void *p, size_t sz)
{
   void *q = malloc(sz);
   memcpy(q, p, sz);
   return q;
}

void stb_pointer_array_free(void **p, int len)
{
   int i;
   for (i=0; i < len; ++i)
      free(p[i]);
}

void **stb_array_block_alloc(int count, int blocksize)
{
   int i;
   char *p = (char *) malloc(sizeof(void *) * count + count * blocksize);
   void **q;
   if (p == NULL) return NULL;
   q = (void **) p;
   p += sizeof(void *) * count;
   for (i=0; i < count; ++i)
      q[i] = p + i * blocksize;
   return q;
}
#endif

#ifdef STB_DEBUG
   // tricky hack to allow recording FILE,LINE even in varargs functions
   #define STB__RECORD_FILE(x)  (stb__record_fileline(__FILE__, __LINE__),(x))
   #define stb_log              STB__RECORD_FILE(stb_log)
   #define stb_                 STB__RECORD_FILE(stb_)
   #ifndef STB_FATAL_CLEAN
   #define stb_fatal            STB__RECORD_FILE(stb_fatal)
   #endif
   #define STB__DEBUG(x)        x
#else
   #define STB__DEBUG(x)
#endif

//////////////////////////////////////////////////////////////////////////////
//
//                         stb_temp
//

#define stb_temp(block, sz)     stb__temp(block, sizeof(block), (sz))

STB_EXTERN void * stb__temp(void *b, int b_sz, int want_sz);
STB_EXTERN void   stb_tempfree(void *block, void *ptr);

#ifdef STB_DEFINE

void * stb__temp(void *b, int b_sz, int want_sz)
{
   if (b_sz >= want_sz)
      return b;
   else
      return malloc(want_sz);
}

void   stb_tempfree(void *b, void *p)
{
   if (p != b)
      free(p);
}
#endif


//////////////////////////////////////////////////////////////////////////////
//
//                      math/sampling operations
//


#define stb_lerp(t,a,b)               ( (a) + (t) * (float) ((b)-(a)) )
#define stb_unlerp(t,a,b)             ( ((t) - (a)) / (float) ((b) - (a)) )

#define stb_clamp(x,xmin,xmax)  ((x) < (xmin) ? (xmin) : (x) > (xmax) ? (xmax) : (x))

STB_EXTERN void stb_newell_normal(float *normal, int num_vert, float **vert, int normalize);
STB_EXTERN void stb_linear_controller(float *curpos, float target_pos, float acc, float deacc, float dt);

STB_EXTERN int stb_float_eq(float x, float y, float delta, int max_ulps);
STB_EXTERN int stb_is_prime(unsigned int m);
STB_EXTERN unsigned int stb_power_of_two_nearest_prime(int n);

STB_EXTERN double stb_linear_remap(double x, double a, double b,
                                             double c, double d);

#ifdef STB_DEFINE
void stb_newell_normal(float *normal, int num_vert, float **vert, int normalize)
{
   int i,j;
   float p;
   normal[0] = normal[1] = normal[2] = 0;
   for (i=num_vert-1,j=0; j < num_vert; i=j++) {
      float *u = vert[i];
      float *v = vert[j];
      normal[0] += (u[1] - v[1]) * (u[2] + v[2]);
      normal[1] += (u[2] - v[2]) * (u[0] + v[0]);
      normal[2] += (u[0] - v[0]) * (u[1] + v[1]);
   }
   if (normalize) {
      p = normal[0]*normal[0] + normal[1]*normal[1] + normal[2]*normal[2];
      p = (float) (1.0 / sqrt(p));
      normal[0] *= p;
      normal[1] *= p;
      normal[2] *= p;
   }
}

void stb_linear_controller(float *curpos, float target_pos, float acc, float deacc, float dt)
{
   float sign = 1, p, cp = *curpos;
   if (cp == target_pos) return;
   if (target_pos < cp) {
      target_pos = -target_pos;
      cp = -cp;
      sign = -1;
   }
   // first decelerate
   if (cp < 0) {
      p = cp + deacc * dt;
      if (p > 0) {
         p = 0;
         dt = dt - cp / deacc;
         if (dt < 0) dt = 0;
      } else {
         dt = 0;
      }
      cp = p;
   }
   // now accelerate
   p = cp + acc*dt;
   if (p > target_pos) p = target_pos;
   *curpos = p * sign;
   // @TODO: testing
}

float stb_quadratic_controller(float target_pos, float curpos, float maxvel, float maxacc, float dt, float *curvel)
{
   return 0; // @TODO
}

int stb_float_eq(float x, float y, float delta, int max_ulps)
{
   if (fabs(x-y) <= delta) return 1;
   if (abs(*(int *)&x - *(int *)&y) <= max_ulps) return 1;
   return 0;
}

int stb_is_prime(unsigned int m)
{
   unsigned int i,j;
   if (m < 2) return 0;
   if (m == 2) return 1;
   if (!(m & 1)) return 0;
   if (m % 3 == 0) return (m == 3);
   for (i=5; (j=i*i), j <= m && j > i; i += 6) {
      if (m %   i   == 0) return 0;
      if (m % (i+2) == 0) return 0;
   }
   return 1;
}

unsigned int stb_power_of_two_nearest_prime(int n)
{
   static signed char tab[32] = { 0,0,0,0,1,0,-1,0,1,-1,-1,3,-1,0,-1,2,1,
                                   0,2,0,-1,-4,-1,5,-1,18,-2,15,2,-1,2,0 };
   if (!tab[0]) {
      int i;
      for (i=0; i < 32; ++i)
         tab[i] = (1 << i) + 2*tab[i] - 1;
      tab[1] = 2;
      tab[0] = 1;
   }
   if (n >= 32) return 0xfffffffb;
   return tab[n];
}

double stb_linear_remap(double x, double x_min, double x_max,
                                  double out_min, double out_max)
{
   return stb_lerp(stb_unlerp(x,x_min,x_max),out_min,out_max);
}
#endif

// create a macro so it's faster, but you can get at the function pointer
#define stb_linear_remap(t,a,b,c,d)   stb_lerp(stb_unlerp(t,a,b),c,d)


//////////////////////////////////////////////////////////////////////////////
//
//                         bit operations
//

#define stb_big32(c)    (((c)[0]<<24) + (c)[1]*65536 + (c)[2]*256 + (c)[3])
#define stb_little32(c) (((c)[3]<<24) + (c)[2]*65536 + (c)[1]*256 + (c)[0])
#define stb_big16(c)    ((c)[0]*256 + (c)[1])
#define stb_little16(c) ((c)[1]*256 + (c)[0])

STB_EXTERN          int stb_bitcount(unsigned int a);
STB_EXTERN unsigned int stb_bitreverse8(unsigned char n);
STB_EXTERN unsigned int stb_bitreverse(unsigned int n);

STB_EXTERN          int stb_is_pow2(unsigned int n);
STB_EXTERN          int stb_log2_ceil(unsigned int n);
STB_EXTERN          int stb_log2_floor(unsigned int n);

STB_EXTERN          int stb_lowbit8(unsigned int n);
STB_EXTERN          int stb_highbit8(unsigned int n);

#ifdef STB_DEFINE
int stb_bitcount(unsigned int a)
{
   a = (a & 0x55555555) + ((a >>  1) & 0x55555555); // max 2
   a = (a & 0x33333333) + ((a >>  2) & 0x33333333); // max 4
   a = (a + (a >> 4)) & 0x0f0f0f0f; // max 8 per 4, now 8 bits
   a = (a + (a >> 8)); // max 16 per 8 bits
   a = (a + (a >> 16)); // max 32 per 8 bits
   return a & 0xff;
}

unsigned int stb_bitreverse8(unsigned char n)
{
   n = ((n & 0xAA) >> 1) + ((n & 0x55) << 1);
   n = ((n & 0xCC) >> 2) + ((n & 0x33) << 2);
   return (unsigned char) ((n >> 4) + (n << 4));
}

unsigned int stb_bitreverse(unsigned int n)
{
  n = ((n & 0xAAAAAAAA) >>  1) | ((n & 0x55555555) << 1);
  n = ((n & 0xCCCCCCCC) >>  2) | ((n & 0x33333333) << 2);
  n = ((n & 0xF0F0F0F0) >>  4) | ((n & 0x0F0F0F0F) << 4);
  n = ((n & 0xFF00FF00) >>  8) | ((n & 0x00FF00FF) << 8);
  return (n >> 16) | (n << 16);
}

int stb_is_pow2(unsigned int n)
{
   return (n & (n-1)) == 0;
}

// tricky use of 4-bit table to identify 5 bit positions (note the '-1')
// 3-bit table would require another tree level; 5-bit table wouldn't save one
#ifdef _WIN32
#pragma warning(push)
#pragma warning(disable: 4035)  // disable warning about no return value
int stb_log2_floor(unsigned int n)
{
   __asm {
      bsr eax,n
      jnz done
      mov eax,-1
   }
   done:;
}
#pragma warning(pop)
#else
int stb_log2_floor(unsigned int n)
{
   static signed char log2_4[16] = { -1,0,1,1,2,2,2,2,3,3,3,3,3,3,3,3 };

   // 2 compares if n < 16, 3 compares otherwise
   if (n < (1U << 14))
        if (n < (1U <<  4))        return     0 + log2_4[n      ];
        else if (n < (1U <<  9))      return  5 + log2_4[n >>  5];
             else                     return 10 + log2_4[n >> 10];
   else if (n < (1U << 24))
             if (n < (1U << 19))      return 15 + log2_4[n >> 15];
             else                     return 20 + log2_4[n >> 20];
        else if (n < (1U << 29))      return 25 + log2_4[n >> 25];
             else                     return 30 + log2_4[n >> 30];
}
#endif

// define ceil from floor
int stb_log2_ceil(unsigned int n)
{
   if (stb_is_pow2(n))  return     stb_log2_floor(n);
   else                 return 1 + stb_log2_floor(n);
}

int stb_highbit8(unsigned int n)
{
   return stb_log2_ceil(n&255);
}

int stb_lowbit8(unsigned int n)
{
   static signed char lowbit4[16] = { -1,0,1,0, 2,0,1,0, 3,0,1,0, 2,0,1,0 };
   int k = lowbit4[n & 15];
   if (k >= 0) return k;
   k = lowbit4[(n >> 4) & 15];
   if (k >= 0) return k+4;
   return k;
}
#endif



//////////////////////////////////////////////////////////////////////////////
//
//                            qsort Compare Routines
//

#ifdef _WIN32
   #define stb_stricmp(a,b) stricmp(a,b)
   #define stb_strnicmp(a,b,n) strnicmp(a,b,n)
#else
   #define stb_stricmp(a,b) strcasecmp(a,b)
   #define stb_strnicmp(a,b,n) strncasecmp(a,b,n)
#endif


STB_EXTERN int stb_intcmp(const void *a, const void *b);
STB_EXTERN int stb_qsort_strcmp(const void *a, const void *b);
STB_EXTERN int stb_qsort_stricmp(const void *a, const void *b);
STB_EXTERN int stb_floatcmp(const void *a, const void *b);
STB_EXTERN int stb_doublecmp(const void *a, const void *b);
STB_EXTERN int stb_charcmp(const void *a, const void *b);
STB_EXTERN void stb_cmpoffset(int off);

#ifdef STB_DEFINE
static int stb__cmpoffset=0;

int stb_intcmp(const void *a, const void *b)
{
   const int p = *(const int *) ((const char *) a + stb__cmpoffset);
   const int q = *(const int *) ((const char *) b + stb__cmpoffset);
   return p < q ? -1 : p > q;
}

int stb_charcmp(const void *a, const void *b)
{
   const int p = *(const unsigned char *) ((const char *) a + stb__cmpoffset);
   const int q = *(const unsigned char *) ((const char *) b + stb__cmpoffset);
   return p < q ? -1 : p > q;
}

int stb_floatcmp(const void *a, const void *b)
{
   const float p = *(const float *) ((const char *) a + stb__cmpoffset);
   const float q = *(const float *) ((const char *) b + stb__cmpoffset);
   return p < q ? -1 : p > q;
}

int stb_doublecmp(const void *a, const void *b)
{
   const double p = *(const double *) ((const char *) a + stb__cmpoffset);
   const double q = *(const double *) ((const char *) b + stb__cmpoffset);
   return p < q ? -1 : p > q;
}

int stb_qsort_strcmp(const void *a, const void *b)
{
   const char *p = *(const char **) ((const char *) a + stb__cmpoffset);
   const char *q = *(const char **) ((const char *) b + stb__cmpoffset);
   return strcmp(p,q);
}

int stb_qsort_stricmp(const void *a, const void *b)
{
   const char *p = *(const char **) ((const char *) a + stb__cmpoffset);
   const char *q = *(const char **) ((const char *) b + stb__cmpoffset);
   return stb_stricmp(p,q);
}

void stb_cmpoffset(int off)
{
   stb__cmpoffset = off;
}
#endif

//////////////////////////////////////////////////////////////////////////////
//
//                           Binary Search Toolkit
//

typedef struct
{
   int minval, maxval, guess;
   int mode, step;
} stb_search;

STB_EXTERN int stb_search_binary(stb_search *s, int minv, int maxv, int find_smallest);
STB_EXTERN int stb_search_open(stb_search *s, int minv, int find_smallest);
STB_EXTERN int stb_probe(stb_search *s, int compare, int *result); // return 0 when done

#ifdef STB_DEFINE
enum
{
   STB_probe_binary_smallest,
   STB_probe_binary_largest,
   STB_probe_open_smallest,
   STB_probe_open_largest,
};

static int stb_probe_guess(stb_search *s, int *result)
{
   switch(s->mode) {
      case STB_probe_binary_largest:
         if (s->minval == s->maxval) {
            *result = s->minval;
            return 0;
         }
         assert(s->minval < s->maxval);
         // if a < b, then a < p <= b
         s->guess = s->minval + (((unsigned) s->maxval - s->minval + 1) >> 1);
         break;

      case STB_probe_binary_smallest:
         if (s->minval == s->maxval) {
            *result = s->minval;
            return 0;
         }
         assert(s->minval < s->maxval);
         // if a < b, then a <= p < b
         s->guess = s->minval + (((unsigned) s->maxval - s->minval) >> 1);
         break;
      case STB_probe_open_smallest:
      case STB_probe_open_largest:
         s->guess = s->maxval;  // guess the current maxval
         break;
   }
   *result = s->guess;
   return 1;
}

int stb_probe(stb_search *s, int compare, int *result)
{
   switch(s->mode) {
      case STB_probe_open_smallest:
      case STB_probe_open_largest: {
         if (compare <= 0) {
            // then it lies within minval & maxval
            if (s->mode == STB_probe_open_smallest)
               s->mode = STB_probe_binary_smallest;
            else
               s->mode = STB_probe_binary_largest;
         } else {
            // otherwise, we need to probe larger
            s->minval  = s->maxval + 1;
            s->maxval  = s->minval + s->step;
            s->step   += s->step;
         }
         break;
      }
      case STB_probe_binary_smallest: {
         // if compare < 0, then s->minval <= a <  p
         // if compare = 0, then s->minval <= a <= p
         // if compare > 0, then         p <  a <= s->maxval
         if (compare <= 0)
            s->maxval = s->guess;
         else
            s->minval = s->guess+1;
         break;
      }
      case STB_probe_binary_largest: {
         // if compare < 0, then s->minval <= a < p
         // if compare = 0, then         p <= a <= s->maxval
         // if compare > 0, then         p <  a <= s->maxval
         if (compare < 0)
            s->maxval = s->guess-1;
         else
            s->minval = s->guess;
         break;
      }
   }
   return stb_probe_guess(s, result);
}

int stb_search_binary(stb_search *s, int minv, int maxv, int find_smallest)
{
   int r;
   if (maxv < minv) return minv-1;
   s->minval = minv;
   s->maxval = maxv;
   s->mode = find_smallest ? STB_probe_binary_smallest : STB_probe_binary_largest;
   stb_probe_guess(s, &r);
   return r;
}

int stb_search_open(stb_search *s, int minv, int find_smallest)
{
   int r;
   s->step   = 4;
   s->minval = minv;
   s->maxval = minv+s->step;
   s->mode = find_smallest ? STB_probe_open_smallest : STB_probe_open_largest;
   stb_probe_guess(s, &r);
   return r;
}
#endif

//////////////////////////////////////////////////////////////////////////////
//
//                           String Processing
//

#define stb_prefixi(s,t)  (0==stb_strnicmp((s),(t),strlen(t)))

enum stb_splitpath_flag
{
   STB_PATH = 1,
   STB_FILE = 2,
   STB_EXT  = 4,
   STB_PATH_FILE = STB_PATH + STB_FILE,
   STB_FILE_EXT  = STB_FILE + STB_EXT,
   STB_EXT_NO_PERIOD = 8,
};

STB_EXTERN char * stb_skipwhite(char *s);
STB_EXTERN char * stb_trimwhite(char *s);
STB_EXTERN char * stb_skipnewline(char *s);
STB_EXTERN char * stb_strncpy(char *s, char *t, int n);
STB_EXTERN char * stb_substr(char *t, int n);
STB_EXTERN char * stb_duplower(char *s);
STB_EXTERN void   stb_tolower (char *s);
STB_EXTERN char * stb_strchr2 (char *s, char p1, char p2);
STB_EXTERN char * stb_strrchr2(char *s, char p1, char p2);
STB_EXTERN char * stb_strtok(char *output, char *src, char *delimit);
STB_EXTERN char * stb_strtok_keep(char *output, char *src, char *delimit);
STB_EXTERN char * stb_strtok_invert(char *output, char *src, char *allowed);
STB_EXTERN char * stb_dupreplace(char *s, char *find, char *replace);
STB_EXTERN void   stb_replaceinplace(char *s, char *find, char *replace);
STB_EXTERN char * stb_splitpath(char *output, char *src, int flag);
STB_EXTERN char * stb_splitpathdup(char *src, int flag);
STB_EXTERN char * stb_replacedir(char *output, char *src, char *dir);
STB_EXTERN char * stb_replaceext(char *output, char *src, char *ext);
STB_EXTERN void   stb_fixpath(char *path);
STB_EXTERN int    stb_suffix (char *s, char *t);
STB_EXTERN int    stb_suffixi(char *s, char *t);
STB_EXTERN int    stb_prefix (char *s, char *t);
STB_EXTERN char * stb_strichr(char *s, char t);
STB_EXTERN char * stb_stristr(char *s, char *t);
STB_EXTERN int    stb_prefix_count(char *s, char *t);
STB_EXTERN char * stb_plural(int n);  // "s" or ""

STB_EXTERN char **stb_tokens(char *src, char *delimit, int *count);
STB_EXTERN char **stb_tokens_nested(char *src, char *delimit, int *count, char *nest_in, char *nest_out);
STB_EXTERN char **stb_tokens_nested_empty(char *src, char *delimit, int *count, char *nest_in, char *nest_out);
STB_EXTERN char **stb_tokens_allowempty(char *src, char *delimit, int *count);
STB_EXTERN char **stb_tokens_stripwhite(char *src, char *delimit, int *count);
STB_EXTERN char **stb_tokens_withdelim(char *src, char *delimit, int *count);
STB_EXTERN char **stb_tokens_quoted(char *src, char *delimit, int *count);
// with 'quoted', allow delimiters to appear inside quotation marks, and don't
// strip whitespace inside them (and we delete the quotation marks unless they
// appear back to back, in which case they're considered escaped)

#ifdef STB_DEFINE

char *stb_plural(int n)
{
   return n == 1 ? "" : "s";
}

int stb_prefix(char *s, char *t)
{
   while (*t)
      if (*s++ != *t++)
         return FALSE;
   return TRUE;
}

int stb_prefix_count(char *s, char *t)
{
   int c=0;
   while (*t) {
      if (*s++ != *t++)
         break;
      ++c;
   }
   return c;
}

int stb_suffix(char *s, char *t)
{
   size_t n = strlen(s);
   size_t m = strlen(t);
   if (m <= n)
      return 0 == strcmp(s+n-m, t);
   else
      return 0;
}

int stb_suffixi(char *s, char *t)
{
   size_t n = strlen(s);
   size_t m = strlen(t);
   if (m <= n)
      return 0 == stb_stricmp(s+n-m, t);
   else
      return 0;
}

// originally I was using this table so that I could create known sentinel
// values--e.g. change whitetable[0] to be true if I was scanning for whitespace,
// and false if I was scanning for nonwhite. I don't appear to be using that
// functionality anymore (I do for tokentable, though), so just replace it
// with isspace()
char *stb_skipwhite(char *s)
{
   while (isspace((unsigned char) *s)) ++s;
   return s;
}

char *stb_skipnewline(char *s)
{
   if (s[0] == '\r' || s[0] == '\n') {
      if (s[0]+s[1] == '\r' + '\n') ++s;
      ++s;
   }
   return s;
}

char *stb_trimwhite(char *s)
{
   int i,n;
   s = stb_skipwhite(s);
   n = (int) strlen(s);
   for (i=n-1; i >= 0; ++i)
      if (!isspace(s[i]))
         break;
   s[i+1] = 0;
   return s;
}

char *stb_strncpy(char *s, char *t, int n)
{
   strncpy(s,t,n);
   s[n-1] = 0;
   return s;
}

char *stb_substr(char *t, int n)
{
   char *a;
   int z = (int) strlen(t);
   if (z < n) n = z;
   a = (char *) malloc(n+1);
   strncpy(a,t,n);
   a[n] = 0;
   return a;
}

char *stb_duplower(char *s)
{
   char *p = strdup(s), *q = p;
   while (*q) {
      *q = tolower(*q);
      ++q;
   }
   return p;
}

void stb_tolower(char *s)
{
   while (*s) {
      *s = tolower(*s);
      ++s;
   }
}

char *stb_strchr2(char *s, char x, char y)
{
   for(; *s; ++s)
      if (*s == x || *s == y)
         return s;
   return NULL;
}

char *stb_strrchr2(char *s, char x, char y)
{
   char *r = NULL;
   for(; *s; ++s)
      if (*s == x || *s == y)
         r = s;
   return r;
}

char *stb_strichr(char *s, char t)
{
   if (tolower(t) == toupper(t))
      return strchr(s,t);
   return stb_strchr2(s, (char) tolower(t), (char) toupper(t));
}

char *stb_stristr(char *s, char *t)
{
   size_t n = strlen(t);
   char *z;
   if (n==0) return s;
   while ((z = stb_strichr(s, *t)) != NULL) {
      if (0==stb_strnicmp(z, t, n))
         return z;
      s = z+1;
   }
   return NULL;
}

static char *stb_strtok_raw(char *output, char *src, char *delimit, int keep, int invert)
{
   if (invert) {
      while (*src && strchr(delimit, *src) != NULL) {
         *output++ = *src++;
      }
   } else {
      while (*src && strchr(delimit, *src) == NULL) {
         *output++ = *src++;
      }
   }
   *output = 0;
   if (keep)
      return src;
   else
      return *src ? src+1 : src;
}

char *stb_strtok(char *output, char *src, char *delimit)
{
   return stb_strtok_raw(output, src, delimit, 0, 0);
}

char *stb_strtok_keep(char *output, char *src, char *delimit)
{
   return stb_strtok_raw(output, src, delimit, 1, 0);
}

char *stb_strtok_invert(char *output, char *src, char *delimit)
{
   return stb_strtok_raw(output, src, delimit, 1,1);
}

static char **stb_tokens_raw(char *src_, char *delimit, int *count,
                             int stripwhite, int allow_empty, char *start, char *end)
{
   int nested = 0;
   unsigned char *src = (unsigned char *) src_;
   static char stb_tokentable[256]; // rely on static initializion to 0
   static char stable[256],etable[256];
   char *out;
   char **result;
   int num=0;
   unsigned char *s;

   s = (unsigned char *) delimit; while (*s) stb_tokentable[*s++] = 1;
   if (start) {
      s = (unsigned char *) start;         while (*s) stable[*s++] = 1;
      s = (unsigned char *) end;   if (s)  while (*s) stable[*s++] = 1;
      s = (unsigned char *) end;   if (s)  while (*s) etable[*s++] = 1;
   }
   stable[0] = 1;

   // two passes through: the first time, counting how many
   s = (unsigned char *) src;
   while (*s) {
      // state: just found delimiter
      // skip further delimiters
      if (!allow_empty) {
         stb_tokentable[0] = 0;
         while (stb_tokentable[*s])
            ++s;
         if (!*s) break;
      }
      ++num;
      // skip further non-delimiters
      stb_tokentable[0] = 1;
      if (stripwhite == 2) { // quoted strings
         while (!stb_tokentable[*s]) {
            if (*s != '"')
               ++s;
            else {
               ++s;
               if (*s == '"')
                  ++s;   // "" -> ", not start a string
               else {
                  // begin a string
                  while (*s) {
                     if (s[0] == '"') {
                        if (s[1] == '"') s += 2; // "" -> "
                        else { ++s; break; } // terminating "
                     } else
                        ++s;
                  }
               }
            }
         }
      } else 
         while (nested || !stb_tokentable[*s]) {
            if (stable[*s]) {
               if (!*s) break;
               if (end ? etable[*s] : nested)
                  --nested;
               else
                  ++nested;
            }
            ++s;
         }
      if (allow_empty) {
         if (*s) ++s;
      }
   }
   // now num has the actual count... malloc our output structure
   // need space for all the strings: strings won't be any longer than
   // original input, since for every '\0' there's at least one delimiter
   result = (char **) malloc(sizeof(*result) * (num+1) + (s-src+1));
   if (result == NULL) return result;
   out = (char *) (result + (num+1));
   // second pass: copy out the data
   s = (unsigned char *) src;
   num = 0;
   nested = 0;
   while (*s) {
      char *last_nonwhite;
      // state: just found delimiter
      // skip further delimiters
      if (!allow_empty) {
         stb_tokentable[0] = 0;
         if (stripwhite)
            while (stb_tokentable[*s] || isspace(*s))
               ++s;
         else
            while (stb_tokentable[*s])
               ++s;
      } else if (stripwhite) {
         while (isspace(*s)) ++s;
      }
      if (!*s) break;
      // we're past any leading delimiters and whitespace
      result[num] = out;
      ++num;
      // copy non-delimiters
      stb_tokentable[0] = 1;
      last_nonwhite = out-1;
      if (stripwhite == 2) {
         while (!stb_tokentable[*s]) {
            if (*s != '"') {
               if (!isspace(*s)) last_nonwhite = out;
               *out++ = *s++;
            } else {
               ++s;
               if (*s == '"') {
                  if (!isspace(*s)) last_nonwhite = out;
                  *out++ = *s++; // "" -> ", not start string
               } else {
                  // begin a quoted string
                  while (*s) {
                     if (s[0] == '"') {
                        if (s[1] == '"') { *out++ = *s; s += 2; }
                        else { ++s; break; } // terminating "
                     } else
                        *out++ = *s++;
                  }
                  last_nonwhite = out-1; // all in quotes counts as non-white
               }
            }
         }
      } else {
         while (nested || !stb_tokentable[*s]) {
            if (!isspace(*s)) last_nonwhite = out;
            if (stable[*s]) {
               if (!*s) break;
               if (end ? etable[*s] : nested)
                  --nested;
               else
                  ++nested;
            }
            *out++ = *s++;
         }
      }

      if (stripwhite) // rewind to last non-whitespace char
         out = last_nonwhite+1;
      *out++ = '\0';

      if (*s) ++s; // skip delimiter
   }
   s = (unsigned char *) delimit; while (*s) stb_tokentable[*s++] = 0;
   if (start) {
      s = (unsigned char *) start;         while (*s) stable[*s++] = 1;
      s = (unsigned char *) end;   if (s)  while (*s) stable[*s++] = 1;
      s = (unsigned char *) end;   if (s)  while (*s) etable[*s++] = 1;
   }
   if (count != NULL) *count = num;
   result[num] = 0;
   return result;
}

char **stb_tokens(char *src, char *delimit, int *count)
{
   return stb_tokens_raw(src,delimit,count,0,0,0,0);
}

char **stb_tokens_nested(char *src, char *delimit, int *count, char *nest_in, char *nest_out)
{
   return stb_tokens_raw(src,delimit,count,0,0,nest_in,nest_out);
}

char **stb_tokens_nested_empty(char *src, char *delimit, int *count, char *nest_in, char *nest_out)
{
   return stb_tokens_raw(src,delimit,count,0,1,nest_in,nest_out);
}

char **stb_tokens_allowempty(char *src, char *delimit, int *count)
{
   return stb_tokens_raw(src,delimit,count,0,1,0,0);
}

char **stb_tokens_stripwhite(char *src, char *delimit, int *count)
{
   return stb_tokens_raw(src,delimit,count,1,1,0,0);
}

char **stb_tokens_quoted(char *src, char *delimit, int *count)
{
   return stb_tokens_raw(src,delimit,count,2,1,0,0);
}

char *stb_dupreplace(char *src, char *find, char *replace)
{
   size_t len_find = strlen(find);
   size_t len_replace = strlen(replace);
   int count = 0;

   char *s,*p,*q;

   s = strstr(src, find);
   if (s == NULL) return strdup(src);
   do {
      ++count;
      s = strstr(s + len_find, find);
   } while (s != NULL);

   p = (char *)  malloc(strlen(src) + count * (len_replace - len_find) + 1);
   if (p == NULL) return p;
   q = p;
   s = src;
   for (;;) {
      char *t = strstr(s, find);
      if (t == NULL) {
         strcpy(q,s);
         assert(strlen(p) == strlen(src) + count*(len_replace-len_find));
         return p;
      }
      memcpy(q, s, t-s);
      q += t-s;
      memcpy(q, replace, len_replace);
      q += len_replace;
      s = t + len_find;
   }
}

void stb_replaceinplace(char *src, char *find, char *replace)
{
   size_t len_find = strlen(find);
   size_t len_replace = strlen(replace);
   int count = 0, delta;

   char *s,*p,*q;

   delta = len_replace - len_find;
   assert(delta <= 0);
   if (delta > 0) return;

   p = strstr(src, find);
   if (p == NULL) return;

   s = q = p;
   while (*s) {
      memcpy(q, replace, len_replace);
      p += len_find;
      q += len_replace;
      s = strstr(p, find);
      if (s == NULL) s = p + strlen(p);
      memmove(q, p, s-p);
      q += s-p;
      p = s;
   }
   *q = 0;
}

void stb_fixpath(char *path)
{
   for(; *path; ++path)
      if (*path == '\\')
         *path = '/';
}

static char *stb__splitpath_raw(char *buffer, char *path, int flag)
{
   int len=0,x,y, n = (int) strlen(path), f1,f2;
   char *s = stb_strrchr2(path, '/', '\\');
   char *t = strrchr(path, '.');
   if (s && t && t < s) t = NULL;
   if (s) ++s;

   if (flag == STB_EXT_NO_PERIOD)
      flag |= STB_EXT;

   if (!(flag & (STB_PATH | STB_FILE | STB_EXT))) return NULL;

   f1 = s == NULL ? 0 : s-path; // start of filename
   f2 = t == NULL ? n : t-path; // just past end of filename

   if (flag & STB_PATH) {
      x = 0; if (f1 == 0 && flag == STB_PATH) len=2;
   } else if (flag & STB_FILE) {
      x = f1;
   } else {
      x = f2;
      if (flag & STB_EXT_NO_PERIOD)
         if (buffer[x] == '.')
            ++x;
   }

   if (flag & STB_EXT)
      y = n;
   else if (flag & STB_FILE)
      y = f2;
   else
      y = f1;

   if (buffer == NULL) {
      buffer = (char *) malloc(y-x + len + 1);
      if (!buffer) return NULL;
   }

   if (len) { strcpy(buffer, "./"); return buffer; }
   strncpy(buffer, path+x, y-x);
   buffer[y-x] = 0;
   return buffer;
}

char *stb_splitpath(char *output, char *src, int flag)
{
   return stb__splitpath_raw(output, src, flag);
}

char *stb_splitpathdup(char *src, int flag)
{
   return stb__splitpath_raw(NULL, src, flag);
}

char *stb_replacedir(char *output, char *src, char *dir)
{
   char buffer[4096];
   stb_splitpath(buffer, src, STB_FILE | STB_EXT);
   if (dir)
      sprintf(output, "%s/%s", dir, buffer);
   else
      strcpy(output, buffer);
   return output;
}

char *stb_replaceext(char *output, char *src, char *ext)
{
   char buffer[4096];
   stb_splitpath(buffer, src, STB_PATH | STB_FILE);
   if (ext)
      sprintf(output, "%s.%s", buffer, ext[0] == '.' ? ext+1 : ext);
   else
      strcpy(output, buffer);
   return output;
}
#endif

//////////////////////////////////////////////////////////////////////////////
//
//                   stb_alloc - hierarchical allocator
//
//                                     inspired by http://swapped.cc/halloc
//
//
// When you alloc a given block through stb_alloc, you have these choices:
//
//       1. does it have a parent?
//       2. can it have children?
//       3. can it be freed directly?
//       4. is it transferrable?
//       5. what is its alignment?
//
// Here are interesting combinations of those:
//
//                              children   free    transfer     alignment
//  arena                          Y         Y         N           n/a
//  no-overhead, chunked           N         N         N         normal
//  string pool alloc              N         N         N            1
//  parent-ptr, chunked            Y         N         N         normal
//  low-overhead, unchunked        N         Y         Y         normal
//  general purpose alloc          Y         Y         Y         normal
//
// Unchunked allocations will probably return 16-aligned pointers. If
// we 16-align the results, we have room for 4 pointers. For smaller
// allocations that allow finer alignment, we can reduce the pointers.
//
// The strategy is that given a pointer, assuming it has a header (only
// the no-overhead allocations have no header), we can determine the
// type of the header fields, and the number of them, by stepping backwards
// through memory and looking at the tags in the bottom bits.
//
// Implementation strategy:
//     chunked allocations come from the middle of chunks, and can't
//     be freed. thefore they do not need to be on a sibling chain.
//     they may need child pointers if they have children.
//
// chunked, with-children
//     void *parent;
//
// unchunked, no-children -- reduced storage
//     void *next_sibling;
//     void *prev_sibling_nextp;
//
// unchunked, general
//     void *first_child;
//     void *next_sibling;
//     void *prev_sibling_nextp;
//     void *chunks;
//
// so, if we code each of these fields with different bit patterns
// (actually same one for next/prev/child), then we can identify which
// each one is from the last field.

STB_EXTERN void  stb_free(void *p);
STB_EXTERN void *stb_malloc_global(size_t size);
STB_EXTERN void *stb_malloc(void *context, size_t size);
STB_EXTERN void *stb_malloc_nofree(void *context, size_t size);
STB_EXTERN void *stb_malloc_leaf(void *context, size_t size);
STB_EXTERN void *stb_malloc_raw(void *context, size_t size);
STB_EXTERN void *stb_realloc(void *ptr, size_t newsize);

STB_EXTERN void stb_reassign(void *new_context, void *ptr);
STB_EXTERN void stb_malloc_validate(void *p, void *parent);

extern int stb_alloc_chunk_size ;
extern int stb_alloc_count_free ;
extern int stb_alloc_count_alloc;
extern int stb_alloc_alignment  ;

#ifdef STB_DEFINE

int stb_alloc_chunk_size  = 65536;
int stb_alloc_count_free  = 0;
int stb_alloc_count_alloc = 0;
int stb_alloc_alignment   = -16;

typedef struct stb__chunk
{
   struct stb__chunk *next;
   int                data_left;
   int                alloc;
} stb__chunk;

typedef struct
{
   void *  next;
   void ** prevn;
} stb__nochildren;

typedef struct
{
   void ** prevn;
   void *  child;
   void *  next;
   stb__chunk *chunks;
} stb__alloc;

typedef struct
{
   stb__alloc *parent;
} stb__chunked;

#define STB__PARENT          1
#define STB__CHUNKS          2

typedef enum
{
   STB__alloc      = STB__CHUNKS,
   STB__chunked    = STB__PARENT,
   STB__nochildren = 0,

   STB__chunk_raw  = 4,
} stb__alloc_type;

#define STB__DECODE(x,v)  ((void *) ((char *) (x) - (v)))
#define STB__ENCODE(x,v)  ((void *) ((char *) (x) + (v)))

#define stb__parent(z)       (stb__alloc *) STB__DECODE((z)->parent, STB__PARENT)
#define stb__chunks(z)       (stb__chunk *) STB__DECODE((z)->chunks, STB__CHUNKS)

#define stb__setparent(z,p)  (z)->parent = (stb__alloc *) STB__ENCODE((p), STB__PARENT)
#define stb__setchunks(z,c)  (z)->chunks = (stb__chunk *) STB__ENCODE((c), STB__CHUNKS)

static stb__alloc stb__alloc_global =
{
   NULL,
   NULL,
   NULL,
   (stb__chunk *) STB__ENCODE(NULL, STB__CHUNKS)
};

static stb__alloc_type stb__identify(void *p)
{
   void **q = (void **) p;
   assert(sizeof(int) == sizeof(*q));
   // @TODO: deal with sizeof(pointer) != sizeof(int)
   return (stb__alloc_type) (((int *) q)[-1] & 3);
}

static void *** stb__prevn(void *p)
{
   if (stb__identify(p) == STB__alloc) {
      stb__alloc      *s = (stb__alloc *) p - 1;
      return &s->prevn;
   } else {
      stb__nochildren *s = (stb__nochildren *) p - 1;
      return &s->prevn;
   }
}

void stb_free(void *p)
{
   if (p == NULL) return;

   // count frees so that unit tests can see what's happening
   ++stb_alloc_count_free;

   switch(stb__identify(p)) {
      case STB__chunked:
         // freeing a chunked-block with children does nothing;
         // they only get freed when the parent does
         // surely this is wrong, and it should free them immediately?
         // otherwise how are they getting put on the right chain?
         return;
      case STB__nochildren: {
         stb__nochildren *s = (stb__nochildren *) p - 1;
         // unlink from sibling chain
         *(s->prevn) = s->next;
         if (s->next)
            *stb__prevn(s->next) = s->prevn;
         free(s);
         return;
      }
      case STB__alloc: {
         stb__alloc *s = (stb__alloc *) p - 1;
         stb__chunk *c, *n;
         void *q;

         // unlink from sibling chain, if any
         *(s->prevn) = s->next;
         if (s->next)
            *stb__prevn(s->next) = s->prevn;

         // first free chunks
         c = (stb__chunk *) stb__chunks(s);
         while (c != NULL) {
            n = c->next;
            stb_alloc_count_free += c->alloc;
            free(c);
            c = n;
         }

         // validating
         stb__setchunks(s,NULL);
         s->prevn = NULL;
         s->next = NULL;

         // now free children
         while ((q = s->child) != NULL) {
            stb_free(q);
         }

         // now free self
         free(s);
         return;
      }
      default:
         assert(0); /* NOTREACHED */
   }
}

void stb_malloc_validate(void *p, void *parent)
{
   if (p == NULL) return;

   switch(stb__identify(p)) {
      case STB__chunked:
         // freeing a chunked-block with children does nothing;
         // they only get freed when the parent does
         return;
      case STB__nochildren: {
         stb__nochildren *n = (stb__nochildren *) p - 1;
         if (n->prevn)
            assert(*n->prevn == p);
         if (n->next) {
            assert(*stb__prevn(n->next) == &n->next);
            stb_malloc_validate(n, parent);
         }
         return;
      }
      case STB__alloc: {
         stb__alloc *s = (stb__alloc *) p - 1;

         if (s->prevn)
            assert(*s->prevn == p);

         if (s->child) {
            assert(*stb__prevn(s->child) == &s->child);
            stb_malloc_validate(s->child, p);
         }

         if (s->next) {
            assert(*stb__prevn(s->next) == &s->next);
            stb_malloc_validate(s->next, parent);
         }
         return;
      }
      default:
         assert(0); /* NOTREACHED */
   }
}

static void * stb__try_chunk(stb__chunk *c, int size, int align, int pre_align)
{
   char *memblock = (char *) (c+1), *q;
   int  iq, start_offset;

   // we going to allocate at the end of the chunk, not the start. confusing,
   // but it means we don't need both a 'limit' and a 'cur', just a 'cur'.
   // the block ends at: p + c->data_left
   //   then we move back by size
   start_offset = c->data_left - size;

   // now we need to check the alignment of that
   q = memblock + start_offset;
   iq = (int) q;
   assert(sizeof(q) == sizeof(iq));

   // suppose align = 2
   // then we need to retreat iq far enough that (iq & (2-1)) == 0
   // to get (iq & (align-1)) = 0 requires subtracting (iq & (align-1))

   start_offset -= iq & (align-1);
   assert(((int) (memblock+start_offset) & (align-1)) == 0);

   // now, if that + pre_align works, go for it!
   start_offset -= pre_align;

   if (start_offset >= 0) {
      c->data_left = start_offset;
      return memblock + start_offset;
   }

   return NULL;
}

static void stb__sort_chunks(stb__alloc *src)
{
   stb__chunk *c = stb__chunks(src), *d;
   if (c == NULL) return;
   d = c->next;
   if (d == NULL) return;
   if (c->data_left > d->data_left) return;

   c->next = d->next;
   d->next = c;
   stb__setchunks(src, d);
}

static void * stb__alloc_chunk(stb__alloc *src, int size, int align, int pre_align)
{
   void *p;
   stb__chunk *c = stb__chunks(src);

   if (c && size <= stb_alloc_chunk_size) {

      p = stb__try_chunk(c, size, align, pre_align);
      if (p) { ++c->alloc; return p; }

      // try a second chunk to reduce wastage
      if (c->next) {
         p = stb__try_chunk(c->next, size, align, pre_align);
         if (p) { ++c->alloc; return p; }
   
         // put the bigger chunk first, since the second will get buried
         // the upshot of this is that, until it gets allocated from, chunk #2
         // is always the largest remaining chunk. (could formalize
         // this with a heap!)
         stb__sort_chunks(src);
         c = stb__chunks(src);
      }
   }

   // allocate a new chunk
   {
      stb__chunk *n;

      int chunk_size = stb_alloc_chunk_size;
      // we're going to allocate a new chunk to put this in
      if (size > chunk_size)
         chunk_size = size;

      assert(sizeof(*n) + pre_align <= 16);

      // loop trying to allocate a large enough chunk
      // the loop is because the alignment may cause problems if it's big
      while (1) {
         n = (stb__chunk *) malloc(16 + chunk_size);
         if (n == NULL) return NULL;

         n->data_left = chunk_size - sizeof(*n);

         p = stb__try_chunk(n, size, align, pre_align);
         if (p != NULL) {
            n->next = c;
            stb__setchunks(src, n);

            // if we just used up the whole block immediately,
            // move the following chunk up
            n->alloc = 1;
            if (size == chunk_size)
               stb__sort_chunks(src);

            return p;
         }

         free(n);
         chunk_size += 16+align;
      }
   }
}

static stb__alloc * stb__get_context(void *context)
{
   if (context == NULL) {
      return &stb__alloc_global;
   } else {
      int u = stb__identify(context);
      // if context is chunked, grab parent
      if (u == STB__chunked) {
         stb__chunked *s = (stb__chunked *) context - 1;
         return stb__parent(s);
      } else {
         return (stb__alloc *) context - 1;
      }
   }
}

static void stb__insert_alloc(stb__alloc *src, stb__alloc *s)
{
   s->prevn = &src->child;
   s->next  = src->child;
   src->child = s+1;
   if (s->next)
      *stb__prevn(s->next) = &s->next;
}

static void stb__insert_nochild(stb__alloc *src, stb__nochildren *s)
{
   s->prevn = &src->child;
   s->next  = src->child;
   src->child = s+1;
   if (s->next)
      *stb__prevn(s->next) = &s->next;
}

static void * malloc_base(void *context, size_t size, stb__alloc_type t, int align)
{
   void *p;

   stb__alloc *src = stb__get_context(context);

   if (align <= 0) {
      // compute worst-case C packed alignment
      // e.g. a 24-byte struct is 8-aligned
      int align_proposed = 1 << stb_lowbit8(size);

      if (align_proposed < 0)
         align_proposed = 4;

      if (align_proposed == 0) {
         if (size == 0)
            align_proposed = 1;
         else
            align_proposed = 256;
      }

      // a negative alignment means 'don't align any larger
      // than this'; so -16 means we align 1,2,4,8, or 16

      if (align < 0) {
         if (align_proposed > -align)
            align_proposed = -align;
      }

      align = align_proposed;
   }

   assert(stb_is_pow2(align));

   // don't cause misalignment when allocating nochildren
   if (t == STB__nochildren && align > 8)
      t = STB__alloc;

   switch (t) {
      case STB__alloc: {
         stb__alloc *s = (stb__alloc *) malloc(size + sizeof(*s));
         if (s == NULL) return NULL;
         p = s+1;
         s->child = NULL;
         stb__insert_alloc(src, s);

         stb__setchunks(s,NULL);
         break;
      }

      case STB__nochildren: {
         stb__nochildren *s = (stb__nochildren *) malloc(size + sizeof(*s));
         if (s == NULL) return NULL;
         p = s+1;
         stb__insert_nochild(src, s);
         break;
      }

      case STB__chunk_raw: {
         p = stb__alloc_chunk(src, size, align, 0);
         if (p == NULL) return NULL;
         break;
      }

      case STB__chunked: {
         stb__chunked *s;
         if (align < 4) align = 4;
         s = (stb__chunked *) stb__alloc_chunk(src, size, align, sizeof(*s));
         if (s == NULL) return NULL;
         stb__setparent(s, src);
         p = s+1;
         break;
      }

      default: assert(0); /* NOTREACHED */
   }

   ++stb_alloc_count_alloc;
   return p;
}

void *stb_malloc_global(size_t size)
{
   return malloc_base(NULL, size, STB__alloc, stb_alloc_alignment);
}

void *stb_malloc(void *context, size_t size)
{
   return malloc_base(context, size, STB__alloc, stb_alloc_alignment);
}

void *stb_malloc_nofree(void *context, size_t size)
{
   return malloc_base(context, size, STB__chunked, stb_alloc_alignment);
}

void *stb_malloc_leaf(void *context, size_t size)
{
   return malloc_base(context, size, STB__nochildren, stb_alloc_alignment);
}

void *stb_malloc_raw(void *context, size_t size)
{
   return malloc_base(context, size, STB__chunk_raw, stb_alloc_alignment);
}

char *stb_malloc_string(void *context, size_t size)
{
   return (char *) malloc_base(context, size, STB__chunk_raw, 1);
}

void *stb_realloc(void *ptr, size_t newsize)
{
   stb__alloc_type t;

   if (ptr == NULL) return stb_malloc(NULL, newsize);
   if (newsize == 0) { stb_free(ptr); return NULL; }
   
   t = stb__identify(ptr);
   assert(t == STB__alloc || t == STB__nochildren);

   if (t == STB__alloc) {
      stb__alloc *s = (stb__alloc *) ptr - 1;

      s = (stb__alloc *) realloc(s, newsize + sizeof(*s));
      if (s == NULL) return NULL;

      ptr = s+1;

      // update pointers
      (*s->prevn) = ptr;
      if (s->next)
         *stb__prevn(s->next) = &s->next;

      if (s->child)
         *stb__prevn(s->child) = &s->child;

      return ptr;
   } else {
      stb__nochildren *s = (stb__nochildren *) ptr - 1;

      s = (stb__nochildren *) realloc(ptr, newsize + sizeof(s));
      if (s == NULL) return NULL;

      // update pointers
      (*s->prevn) = s+1;
      if (s->next)
         *stb__prevn(s->next) = &s->next;

      return s+1;
   }
}

void *stb_realloc_c(void *context, void *ptr, size_t newsize)
{
   if (ptr == NULL) return stb_malloc(context, newsize);
   if (newsize == 0) { stb_free(ptr); return NULL; }
   // @TODO: verify you haven't changed contexts
   return stb_realloc(ptr, newsize);
}

void stb_reassign(void *new_context, void *ptr)
{
   stb__alloc *src = stb__get_context(new_context);

   stb__alloc_type t = stb__identify(ptr);
   assert(t == STB__alloc || t == STB__nochildren);

   if (t == STB__alloc) {
      stb__alloc *s = (stb__alloc *) ptr - 1;

      // unlink from old
      *(s->prevn) = s->next;
      if (s->next)
         *stb__prevn(s->next) = s->prevn;

      stb__insert_alloc(src, s);
   } else {
      stb__nochildren *s = (stb__nochildren *) ptr - 1;

      // unlink from old
      *(s->prevn) = s->next;
      if (s->next)
         *stb__prevn(s->next) = s->prevn;

      stb__insert_nochild(src, s);
   }
}

#endif


//////////////////////////////////////////////////////////////////////////////
//
//                                stb_arr
//
//  An stb_arr is directly useable as a pointer (use the actual type in your
//  definition), but when it resizes, it returns a new pointer and you can't
//  use the old one, so you have to be careful to copy-in-out as necessary.
//
//  Use a NULL pointer as a 0-length array.
//
//     float *my_array = NULL, *temp;
//
//     // add elements on the end one at a time
//     stb_arr_push(my_array, 0.0f);
//     stb_arr_push(my_array, 1.0f);
//     stb_arr_push(my_array, 2.0f);
//
//     assert(my_array[1] == 2.0f);
//
//     // add an uninitialized element at the end, then assign it
//     *stb_arr_add(my_array) = 3.0f;
//
//     // add three uninitialized elements at the end
//     temp = stb_arr_addn(my_array,3);
//     temp[0] = 4.0f;
//     temp[1] = 5.0f;
//     temp[2] = 6.0f;
//
//     assert(my_array[5] == 5.0f);
//
//     // remove the last one
//     stb_arr_pop(my_array);
//
//     assert(stb_arr_len(my_array) == 6);


#ifdef STB_MALLOC_WRAPPER
  #define STB__PARAMS    , char *file, int line
  #define STB__ARGS      ,       file,     line
#else
  #define STB__PARAMS
  #define STB__ARGS
#endif

// calling this function allocates an empty stb_arr attached to p
// (whereas NULL isn't attached to anything)
STB_EXTERN void stb_arr_malloc(void **target, void *context);

// call this function with a non-NULL value to have all successive
// stbs that are created be attached to the associated parent. Note
// that once a given stb_arr is non-empty, it stays attached to its
// current parent, even if you call this function again.
// it turns the previous value, so you can restore it
STB_EXTERN void* stb_arr_malloc_parent(void *p);

// simple functions written on top of other functions
#define stb_arr_empty(a)       (  stb_arr_len(a) == 0 )
#define stb_arr_add(a)         (  stb_arr_addn((a),1) )
#define stb_arr_push(a,v)      ( *stb_arr_add(a)=(v)  )


#ifdef __cplusplus
#define STB__CAST(x)           (x).cast()
#else
#define STB__CAST(x)           ((stb__arr *) (x))
#endif

typedef struct
{
   int len, limit;
   int stb_malloc;
   unsigned int signature;
} stb__arr;

#define stb_arr_signature      0x51bada7b  // ends with 0123 in decimal

// access the header block stored before the data
#define stb_arrhead(a)         /*lint --e(826)*/ (STB__CAST(a) - 1)
#define stb_arrhead2(a)        /*lint --e(826)*/ (((stb__arr *) (a)) - 1)

#ifdef STB_DEBUG
#define stb_arr_check(a)       assert(!a || stb_arrhead(a)->signature == stb_arr_signature)
#define stb_arr_check2(a)      assert(!a || stb_arrhead2(a)->signature == stb_arr_signature)
#else
#define stb_arr_check(a)       0
#define stb_arr_check2(a)      0
#endif

// ARRAY LENGTH

// get the array length; special case if pointer is NULL
#define stb_arr_len(a)         (STB__CAST(a) ? stb_arrhead(a)->len : 0)
#define stb_arr_len2(a)        ((stb__arr *) (a) ? stb_arrhead2(a)->len : 0)
#define stb_arr_lastn(a)       (stb_arr_len(a)-1)

// check whether a given index is valid -- tests 0 <= i < stb_arr_len(a) 
#define stb_arr_valid(a,i)     (STB__CAST(a) ? (unsigned int) (i) < stb_arrhead(a)->len : 0)

// change the array length so is is exactly N entries long, creating
// uninitialized entries as needed
#define stb_arr_setlen(a,n)  \
            ((a)=stb__arr_setlen((a), sizeof(a[0]), (n)))

// change the array length so that N is a valid index (that is, so
// it is at least N entries long), creating uninitialized entries as needed
#define stb_arr_makevalid(a,n)  \
            (stb_arr_len(a) < (n)+1 ? stb_arr_setlen((a),(n)+1) : (a))

// remove the last element of the array, returning it
#define stb_arr_pop(a)         ((stb_arr_check(a), (a))[--stb_arrhead(a)->len])

// access the last element in the array
#define stb_arr_last(a)        ((stb_arr_check(a), (a))[stb_arr_len(a)-1])

// is iterator at end of list?
#define stb_arr_end(a,i)       ((i) >= &(a)[stb_arr_len(a)])

// (internal) change the allocated length of the array
#define stb_arr__grow(a,n)     (stb_arr_check(a), stb_arrhead(a)->len += (n))

// add N new unitialized elements to the end of the array
#define stb_arr__addn(a,n)     /*lint --e(826)*/ \
                               ((stb_arr_len(a)+(n) > stb_arrcurmax(a))      \
                                 ? ((a)=stb__arr_addlen((a),sizeof(*a),(n))) \
                                 : ((stb_arr__grow(a,n), (a))))

// add N new unitialized elements to the end of the array, and return
// a pointer to the first new one
#define stb_arr_addn(a,n)      (stb_arr__addn(a,n),(a)+stb_arr_len(a)-(n))

// add N new uninitialized elements starting at index 'i'
#define stb_arr_insertn(a,i,n) ((a) = stb__arr_insertn(a, sizeof(*a), i, n))

// insert an element at i
#define stb_arr_insert(a,i,v)  ((a) = stb__arr_insertn(a, sizeof(*a), i, n), ((a)[i] = v))

// delete N elements from the middle starting at index 'i'
#define stb_arr_deleten(a,i,n) ((a) = stb__arr_deleten(a, sizeof(*a), i, n))

// delete the i'th element
#define stb_arr_delete(a,i)   stb_arr_deleten(a,i,1)

// delete the i'th element, swapping down from the end
#define stb_arr_fastdelete(a,i)  \
   (stb_swap(&a[i], &a[stb_arrhead(a)->len-1], sizeof(*a)), stb_arr_pop(a))


// ARRAY STORAGE

// get the array maximum storage; special case if NULL
#define stb_arrcurmax(a)       (STB__CAST(a) ? stb_arrhead(a)->limit : 0)
#define stb_arrcurmax2(a)      ((a) ? stb_arrhead2(a)->limit : 0)

// set the maxlength of the array to n in anticipation of further growth
#define stb_arr_setsize(a,n)   (stb_arr_check(a), (a)=stb__arr_setsize(a,sizeof((a)[0]),n))

// make sure maxlength is large enough for at least N new allocations
#define stb_arr_atleast(a,n)   (stb_arr_len(a)+(n) > stb_arrcurmax(a)      \
                                 ? stb_arr_setsize((a), (n)) : 0)

// make a copy of a given array (copies contents via 'memcpy'!)
#define stb_arr_copy(a)        stb__arr_copy(a, sizeof((a)[0]))

// compute the storage needed to store all the elements of the array
#define stb_arr_storage(a)     (stb_arr_len(a) * sizeof((a)[0]))

#define stb_arr_for(v,arr)     for((v)=(arr); (v) < (arr)+stb_arr_len(arr); ++(v))

// IMPLEMENTATION

STB_EXTERN void *stb_arr_free_(void *p);
STB_EXTERN void *stb__arr_copy_(void *p, int elem_size);
STB_EXTERN void *stb__arr_setsize_(void *p, int size, int limit  STB__PARAMS);
STB_EXTERN void *stb__arr_setlen_(void *p, int size, int newlen  STB__PARAMS);
STB_EXTERN void *stb__arr_addlen_(void *p, int size, int addlen  STB__PARAMS);
STB_EXTERN void *stb__arr_deleten_(void *p, int size, int loc, int n  STB__PARAMS);
STB_EXTERN void *stb__arr_insertn_(void *p, int size, int loc, int n  STB__PARAMS);

#ifdef __cplusplus

// in C++, wrap all the above function calls in a template to avoid type error

#define STB__ARR(t)          stb_arr<t >

template<class T> struct stb_arr
{
   T *ptr;

   // constructors
   stb_arr<T>(void *p) { ptr = (T *) p; }
   stb_arr<T>() { ptr = NULL; }

   // operator overloads
   operator T*() { return ptr; }
   stb__arr * cast() { return (stb__arr *) ptr; }
   T& operator[] (unsigned i) { return ptr[i]; }
   T& operator[] (int i     ) { return ptr[i]; }

   stb_arr<T> stb_arr_free__()                { return stb_arr<T>(stb_arr_free_(ptr)); }

   stb_arr<T> stb__arr_copy__(int elem_size) { return stb_arr<T>(stb__arr_copy_(ptr,elem_size)); }
   stb_arr<T> stb__arr_setsize__(int size, int limit        STB__PARAMS)
   { return stb_arr<T>(stb__arr_setsize_(ptr, size, limit  STB__ARGS)); }
   stb_arr<T> stb__arr_setlen__(int size, int newlen        STB__PARAMS)
   { return stb_arr<T>(stb__arr_setlen_(ptr, size, newlen  STB__ARGS)); }
   stb_arr<T> stb__arr_addlen__(int size, int addlen        STB__PARAMS)
   { return stb_arr<T>(stb__arr_addlen_(ptr, size, addlen  STB__ARGS)); }
   stb_arr<T> stb__arr_deleten__(int size, int loc, int n    STB__PARAMS)
   { return stb_arr<T>(stb__arr_deleten_(ptr, size, loc, n STB__ARGS)); }
   stb_arr<T> stb__arr_insertn__(int size, int loc, int n    STB__PARAMS)
   { return stb_arr<T>(stb__arr_insertn_(ptr, size, loc, n STB__ARGS)); }
};

#define stb_arr_free(p)           (p).stb_arr_free__()
#define stb__arr_copy(p,e)        (p).stb__arr_copy__(e)

#ifndef STB_MALLOC_WRAPPER
  #define stb__arr_setsize(p,s,n)   (p).stb__arr_setsize__(s,n)
  #define stb__arr_setlen(p,s,n)    (p).stb__arr_setlen__(s,n)
  #define stb__arr_addlen(p,s,n)    (p).stb__arr_addlen__(s,n)
  #define stb__arr_deleten(p,s,i,n) (p).stb__arr_deleten__(s,i,n)
  #define stb__arr_insertn(p,s,i,n) (p).stb__arr_insertn__(s,i,n)
#else
  #define stb__arr_setsize(p,s,n)   (p).stb__arr_setsize__(s,n,__FILE__,__LINE__)
  #define stb__arr_setlen(p,s,n)    (p).stb__arr_setlen__(s,n,__FILE__,__LINE__)
  #define stb__arr_addlen(p,s,n)    (p).stb__arr_addlen__(s,n,__FILE__,__LINE__)
  #define stb__arr_deleten(p,s,i,n) (p).stb__arr_deleten__(s,i,n,__FILE__,__LINE__)
  #define stb__arr_insertn(p,s,i,n) (p).stb__arr_insertn__(s,i,n,__FILE__,__LINE__)
#endif

#else

#define STB__ARR(t)          t *

#define stb_arr_free               stb_arr_free_
#define stb__arr_copy              stb__arr_copy_

#ifndef STB_MALLOC_WRAPPER
  #define stb__arr_setsize         stb__arr_setsize_
  #define stb__arr_setlen          stb__arr_setlen_
  #define stb__arr_addlen          stb__arr_addlen_
  #define stb__arr_deleten         stb__arr_deleten_
  #define stb__arr_insertn         stb__arr_insertn_
#else
  #define stb__arr_addlen(p,s,n)    stb__arr_addlen_(p,s,n,__FILE__,__LINE__)
  #define stb__arr_setlen(p,s,n)    stb__arr_setlen_(p,s,n,__FILE__,__LINE__)
  #define stb__arr_setsize(p,s,n)   stb__arr_setsize_(p,s,n,__FILE__,__LINE__)
  #define stb__arr_deleten(p,s,i,n) stb__arr_deleten_(p,s,i,n,__FILE__,__LINE__)
  #define stb__arr_insertn(p,s,i,n) stb__arr_insertn_(p,s,i,n,__FILE__,__LINE__)
#endif

#endif

#define stb_arr(x)           STB__ARR(x)

#ifdef STB_DEFINE
static void *stb__arr_context;

void *stb_arr_malloc_parent(void *p)
{
   void *q = stb__arr_context;
   stb__arr_context = p;
   return q;
}

void stb_arr_malloc(void **target, void *context)
{
   stb__arr *q = (stb__arr *) stb_malloc(context, sizeof(*q));
   q->len = q->limit = 0;
   q->stb_malloc = 1;
   q->signature = stb_arr_signature;
   *target = (void *) (q+1);
}

static void * stb__arr_malloc(int size)
{
   if (stb__arr_context)
      return stb_malloc(stb__arr_context, size);
   return malloc(size);
}

void * stb__arr_copy_(void *p, int elem_size)
{
   stb__arr *q;
   if (p == NULL) return p;
   q = (stb__arr *) stb__arr_malloc(sizeof(*q) + elem_size * stb_arrhead2(p)->limit);
   stb_arr_check2(p);
   memcpy(q, stb_arrhead2(p), sizeof(*q) + elem_size * stb_arrhead2(p)->len);
   q->stb_malloc = !!stb__arr_context;
   return q+1;
}

void * stb_arr_free_(void *p)
{
   stb_arr_check2(p);
   if (p) {
      stb__arr *q = stb_arrhead2(p);
      if (q->stb_malloc)
         stb_free(q);
      else
         free(q);
   }
   return NULL;
}

static void *stb__arrsize_(void *p, int size, int limit, int len  STB__PARAMS)
{
   stb__arr *a;
   stb_arr_check2(p);
   if (p == NULL) {
      if (len == 0 && size == 0) return p;
      a = (stb__arr *) stb__arr_malloc(sizeof(*a) + size*limit);
      a->limit = limit;
      a->len   = len;
      a->stb_malloc = !!stb__arr_context;
      a->signature = stb_arr_signature;
   } else {
      a = stb_arrhead2(p);
      a->len = len;
      if (a->limit < limit) {
         void *p;
         if (a->limit >= 4 && limit < a->limit * 2)
            limit = a->limit * 2;
         if (a->stb_malloc)
            p = stb_realloc(a, sizeof(*a) + limit*size);
         else
            #ifdef STB_MALLOC_WRAPPER
            p = stb__realloc(a, sizeof(*a) + limit*size, file, line);
            #else
            p = realloc(a, sizeof(*a) + limit*size);
            #endif
         if (p) {
            a = (stb__arr *) p;
            a->limit = limit;
         } else {
            // throw an error!
         }
      }
   }
   a->len   = stb_min(a->len, a->limit);
   return a+1;
}

void *stb__arr_setsize_(void *p, int size, int limit  STB__PARAMS)
{
   stb_arr_check2(p);
   return stb__arrsize_(p, size, limit, stb_arr_len2(p)  STB__ARGS);
}

void *stb__arr_setlen_(void *p, int size, int newlen  STB__PARAMS)
{
   stb_arr_check2(p);
   if (stb_arrcurmax2(p) < newlen || p == NULL) {
      return stb__arrsize_(p, size, newlen, newlen  STB__ARGS);
   } else {
      stb_arrhead2(p)->len = newlen;
      return p;
   }
}

void *stb__arr_addlen_(void *p, int size, int addlen  STB__PARAMS)
{
   return stb__arr_setlen_(p, size, stb_arr_len2(p) + addlen  STB__ARGS);
}

void *stb__arr_insertn_(void *p, int size, int i, int n  STB__PARAMS)
{
   if (n) {
      int z;

      if (p == NULL)
         return stb__arr_addlen_(p, size, n  STB__ARGS);

      z = stb_arr_len2(p);
      p = stb__arr_addlen_(p, size, i  STB__ARGS);
      memmove((char *) p + (i+n)*size, (char *) p + i*size, size * (z-i));
   }
   return p;
}

void *stb__arr_deleten_(void *p, int size, int i, int n  STB__PARAMS)
{
   if (n) {
      memmove((char *) p + i*size, (char *) p + (i+n)*size, size * (stb_arr_len2(p)-i));
      stb_arrhead2(p)->len -= n;
   }
   return p;
}

#endif

//////////////////////////////////////////////////////////////////////////////
//
//                               Hashing
//
//      typical use for this is to make a power-of-two hash table.
//
//      let N = size of table (2^n)
//      let H = stb_hash(str)
//      let S = stb_rehash(H) | 1
//
//      then hash probe sequence P(i) for i=0..N-1
//         P(i) = (H + S*i) & (N-1)
//
//      the idea is that H has 32 bits of hash information, but the
//      table has only, say, 2^20 entries so only uses 20 of the bits.
//      then by rehashing the original H we get 2^12 different probe
//      sequences for a given initial probe location. (So it's optimal
//      for 64K tables and its optimality decreases past that.)
//
//      ok, so I've added something that generates _two separate_
//      32-bit hashes simultaneously which should scale better to
//      very large tables.


STB_EXTERN unsigned int stb_hash(char *str);
STB_EXTERN unsigned int stb_hashptr(void *p);
STB_EXTERN unsigned int stb_hashlen(char *str, int len);
STB_EXTERN unsigned int stb_rehash_improved(unsigned int v);
STB_EXTERN unsigned int stb_hash_fast(void *p, int len);
STB_EXTERN unsigned int stb_hash2(char *str, unsigned int *hash2_ptr);
STB_EXTERN unsigned int stb_hash_number(unsigned int hash);

#define stb_rehash(x)  ((x) + ((x) >> 6) + ((x) >> 19))

#ifdef STB_DEFINE
unsigned int stb_hash(char *str)
{
   unsigned int hash = 0;
   while (*str)
      hash = (hash << 7) + (hash >> 25) + *str++;
   return hash + (hash >> 16);
}

unsigned int stb_hashlen(char *str, int len)
{
   unsigned int hash = 0;
   while (len-- > 0 && *str)
      hash = (hash << 7) + (hash >> 25) + *str++;
   return hash + (hash >> 16);
}

unsigned int stb_hashptr(void *p)
{
   unsigned int x = (unsigned int) p;

   // typically lacking in low bits and high bits
   x = stb_rehash(x);
   x += x << 16;

   // pearson's shuffle
   x ^= x << 3;
   x += x >> 5;
   x ^= x << 2;
   x += x >> 15;
   x ^= x << 10;
   return stb_rehash(x);
}

unsigned int stb_rehash_improved(unsigned int v)
{
   return stb_hashptr((void *) v);
}

unsigned int stb_hash2(char *str, unsigned int *hash2_ptr)
{
   unsigned int hash1 = 0x3141592c;
   unsigned int hash2 = 0x77f044ed;
   while (*str) {
      hash1 = (hash1 << 7) + (hash1 >> 25) + *str;
      hash2 = (hash2 << 11) + (hash2 >> 21) + *str;
      ++str;
   }
   *hash2_ptr = hash2 + (hash1 >> 16);
   return       hash1 + (hash2 >> 16);
}

// Paul Hsieh hash
#define stb__get16_slow(p) ((p)[0] + ((p)[1] << 8))
#if defined(_MSC_VER)
   #define stb__get16(p) (*((unsigned short *) (p)))
#else
   #define stb__get16(p) stb__get16_slow(p)
#endif

unsigned int stb_hash_fast(void *p, int len)
{
   unsigned char *q = (unsigned char *) p;
   unsigned int hash = len;

   if (len <= 0 || q == NULL) return 0;

   /* Main loop */
   if (((int) q & 1) == 0) {
      for (;len > 3; len -= 4) {
         unsigned int val;
         hash +=  stb__get16(q);
         val   = (stb__get16(q+2) << 11);
         hash  = (hash << 16) ^ hash ^ val;
         q    += 4;
         hash += hash >> 11;
      }
   } else {
      for (;len > 3; len -= 4) {
         unsigned int val;
         hash +=  stb__get16_slow(q);
         val   = (stb__get16_slow(q+2) << 11);
         hash  = (hash << 16) ^ hash ^ val;
         q    += 4;
         hash += hash >> 11;
      }
   }

   /* Handle end cases */
   switch (len) {
      case 3: hash += stb__get16_slow(q);
              hash ^= hash << 16;
              hash ^= q[2] << 18;
              hash += hash >> 11;
              break;
      case 2: hash += stb__get16_slow(q);
              hash ^= hash << 11;
              hash += hash >> 17;
              break;
      case 1: hash += q[0];
              hash ^= hash << 10;
              hash += hash >> 1;
              break;
      case 0: break;
   }

   /* Force "avalanching" of final 127 bits */
   hash ^= hash << 3;
   hash += hash >> 5;
   hash ^= hash << 4;
   hash += hash >> 17;
   hash ^= hash << 25;
   hash += hash >> 6;

   return hash;
}

unsigned int stb_hash_number(unsigned int hash)
{
   hash ^= hash << 3;
   hash += hash >> 5;
   hash ^= hash << 4;
   hash += hash >> 17;
   hash ^= hash << 25;
   hash += hash >> 6;
   return hash;
}

#endif

//////////////////////////////////////////////////////////////////////////////
//
//                     Perfect hashing for ints/pointers
//
//   This is mainly useful for making faster pointer-indexed tables
//   that don't change frequently. E.g. for stb_ischar().
//

typedef struct
{
   stb_uint32  addend;
   stb_uint    multiplicand;
   stb_uint    b_mask;
   stb_uint8   small_bmap[16];
   stb_uint16  *large_bmap;

   stb_uint table_mask;
   stb_uint32 *table;
} stb_perfect;

STB_EXTERN int stb_perfect_create(stb_perfect *,unsigned int*,int n);
STB_EXTERN void stb_perfect_destroy(stb_perfect *);
STB_EXTERN int stb_perfect_hash(stb_perfect *, unsigned int x);
extern int stb_perfect_hash_max_failures;

#ifdef STB_DEFINE

int stb_perfect_hash_max_failures;

int stb_perfect_hash(stb_perfect *p, unsigned int x)
{
   stb_uint m = x * p->multiplicand;
   stb_uint y = x >> 16;
   stb_uint bv = (m >> 24) + y;
   stb_uint av = (m + y) >> 12;
   if (p->table == NULL) return -1;  // uninitialized table fails
   bv &= p->b_mask;
   av &= p->table_mask;
   if (p->large_bmap)
      av ^= p->large_bmap[bv];
   else
      av ^= p->small_bmap[bv];
   return p->table[av] == x ? av : -1;
}

static void stb__perfect_prehash(stb_perfect *p, stb_uint x, stb_uint16 *a, stb_uint16 *b)
{
   stb_uint m = x * p->multiplicand;
   stb_uint y = x >> 16;
   stb_uint bv = (m >> 24) + y;
   stb_uint av = (m + y) >> 12;
   bv &= p->b_mask;
   av &= p->table_mask;
   *b = bv;
   *a = av;
}

static unsigned long stb__perfect_rand(void)
{
   static unsigned long stb__rand;
   stb__rand = stb__rand * 2147001325 + 715136305;
   return 0x31415926 ^ ((stb__rand >> 16) + (stb__rand << 16));
}

typedef struct {
   unsigned short count;
   unsigned short b;
   unsigned short map;
   unsigned short *entries;
} stb__slot;

static int stb__slot_compare(const void *p, const void *q)
{
   stb__slot *a = (stb__slot *) p;
   stb__slot *b = (stb__slot *) q;
   return a->count > b->count ? -1 : a->count < b->count;  // sort large to small
}

int stb_perfect_create(stb_perfect *p, unsigned int *v, int n)
{
   unsigned int buffer1[64], buffer2[64], buffer3[64], buffer4[64], buffer5[32];
   unsigned short *as = (unsigned short *) stb_temp(buffer1, sizeof(*v)*n);
   unsigned short *bs = (unsigned short *) stb_temp(buffer2, sizeof(*v)*n);
   unsigned short *entries = (unsigned short *) stb_temp(buffer4, sizeof(*entries) * n);
   int size = 1 << stb_log2_ceil(n), bsize=8;
   int failure = 0,i,j,k;

   assert(n <= 32768);
   p->large_bmap = NULL;

   for(;;) {
      stb__slot *bcount = (stb__slot *) stb_temp(buffer3, sizeof(*bcount) * bsize);
      unsigned short *bloc = (unsigned short *) stb_temp(buffer5, sizeof(*bloc) * bsize);
      unsigned short *e;
      int bad=0;

      p->addend = stb__perfect_rand();
      p->multiplicand = stb__perfect_rand() | 1;
      p->table_mask = size-1;
      p->b_mask = bsize-1;
      p->table = (stb_uint32 *) malloc(size * sizeof(*p->table));

      for (i=0; i < bsize; ++i) {
         bcount[i].b     = i;
         bcount[i].count = 0;
         bcount[i].map   = 0;
      }
      for (i=0; i < n; ++i) {
         stb__perfect_prehash(p, v[i], as+i, bs+i);
         ++bcount[bs[i]].count;
      }
      qsort(bcount, bsize, sizeof(*bcount), stb__slot_compare);
      e = entries; // now setup up their entries index
      for (i=0; i < bsize; ++i) {
         bcount[i].entries = e;
         e += bcount[i].count;
         bcount[i].count = 0;
         bloc[bcount[i].b] = i;
      }
      // now fill them out
      for (i=0; i < n; ++i) {
         int b = bs[i];
         int w = bloc[b];
         bcount[w].entries[bcount[w].count++] = i;
      }
      stb_tempfree(buffer5,bloc);
      // verify
      for (i=0; i < bsize; ++i)
         for (j=0; j < bcount[i].count; ++j)
            assert(bs[bcount[i].entries[j]] == bcount[i].b);
      memset(p->table, 0, size*sizeof(*p->table));

      // check if any b has duplicate a
      for (i=0; i < bsize; ++i) {
         if (bcount[i].count > 1) {
            for (j=0; j < bcount[i].count; ++j) {
               if (p->table[as[bcount[i].entries[j]]])
                  bad = 1;
               p->table[as[bcount[i].entries[j]]] = 1;
            }
            for (j=0; j < bcount[i].count; ++j) {
               p->table[as[bcount[i].entries[j]]] = 0;
            }
            if (bad) break;
         }
      }

      if (!bad) {
         // go through the bs and populate the table, first fit
         for (i=0; i < bsize; ++i) {
            if (bcount[i].count) {
               // go through the candidate table[b] values
               for (j=0; j < size; ++j) {
                  // go through the a values and see if they fit
                  for (k=0; k < bcount[i].count; ++k) {
                     int a = as[bcount[i].entries[k]];
                     if (p->table[(a^j)&p->table_mask]) {
                        break; // fails
                     }
                  }
                  // if succeeded, accept
                  if (k == bcount[i].count) {
                     bcount[i].map = j;
                     for (k=0; k < bcount[i].count; ++k) {
                        int a = as[bcount[i].entries[k]];
                        p->table[(a^j)&p->table_mask] = 1;
                     }
                     break;
                  }
               }
               if (j == size)
                  break; // no match for i'th entry, so break out in failure
            }
         }
         if (i == bsize) {
            // success... fill out map
            if (bsize <= 16 && size <= 256) {
               p->large_bmap = NULL;
               for (i=0; i < bsize; ++i)
                  p->small_bmap[bcount[i].b] = (stb_uint8) bcount[i].map;
            } else {
               p->large_bmap = (unsigned short *) malloc(sizeof(*p->large_bmap) * bsize);
               for (i=0; i < bsize; ++i)
                  p->large_bmap[bcount[i].b] = bcount[i].map;
            }

            // initialize table to v[0], so empty slots will fail
            for (i=0; i < size; ++i)
               p->table[i] = v[0];

            for (i=0; i < n; ++i)
               if (p->large_bmap)
                  p->table[as[i] ^ p->large_bmap[bs[i]]] = v[i];
               else
                  p->table[as[i] ^ p->small_bmap[bs[i]]] = v[i];

            // and now validate that none of them collided
            for (i=0; i < n; ++i)
               assert(stb_perfect_hash(p, v[i]) >= 0);

            stb_tempfree(buffer3, bcount);
            break;
         }
      }
      free(p->table);
      p->table = NULL;
      stb_tempfree(buffer3, bcount);

      ++failure;
      if (failure >= 4 && bsize < size) bsize *= 2;
      if (failure >= 8 && (failure & 3) == 0 && size < 4*n) {
         size *= 2;
         bsize *= 2;
      }
      if (failure == 6) {
         // make sure the input data is unique, so we don't infinite loop
         unsigned int *data = (unsigned int *) stb_temp(buffer3, n * sizeof(*data));
         memcpy(data, v, sizeof(*data) * n);
         qsort(data, n, sizeof(*data), stb_intcmp);
         for (i=1; i < n; ++i) {
            if (data[i] == data[i-1])
               size = 0; // size is return value, so 0 it
         }
         stb_tempfree(buffer3, data);
         if (!size) break;
      }
   }

   if (failure > stb_perfect_hash_max_failures)
      stb_perfect_hash_max_failures = failure;

   stb_tempfree(buffer1, as);
   stb_tempfree(buffer2, bs);
   stb_tempfree(buffer4, entries);

   return size;
}

void stb_perfect_destroy(stb_perfect *p)
{
   if (p->large_bmap) free(p->large_bmap);
   if (p->table     ) free(p->table);
   p->large_bmap = NULL;
   p->table      = NULL;
   p->b_mask     = 0;
   p->table_mask = 0;
}
#endif

//////////////////////////////////////////////////////////////////////////////
//
//                     Perfect hash clients

STB_EXTERN int    stb_ischar(char s, char *set);

#ifdef STB_DEFINE

int stb_ischar(char c, char *set)
{
   static unsigned char bit[8] = { 1,2,4,8,16,32,64,128 };
   static stb_perfect p;
   static unsigned char (*tables)[256];
   static STB__ARR(char *) sets = NULL;

   int z = stb_perfect_hash(&p, (int) set);
   if (z < 0) {
      int i,k,n,j,f;
      // special code that means free all existing data
      if (set == NULL) {
         sets = stb_arr_free(sets);
         free(tables);
         tables = NULL;
         stb_perfect_destroy(&p);
         return 0;
      }
      stb_arr_push(sets, set);
      stb_perfect_destroy(&p);
      n = stb_perfect_create(&p, (unsigned int *) (char **) sets, stb_arr_len(sets));
      assert(n != 0);
      k = (n+7) >> 3;
      tables = (unsigned char (*)[256]) realloc(tables, sizeof(*tables) * k);
      memset(tables, 0, sizeof(*tables) * k);
      for (i=0; i < stb_arr_len(sets); ++i) {
         k = stb_perfect_hash(&p, (int) sets[i]);
         assert(k >= 0);
         n = k >> 3;
         f = bit[k&7];
         for (j=0; !j || sets[i][j]; ++j) {
            tables[n][(unsigned char) sets[i][j]] |= f;
         }
      }
      z = stb_perfect_hash(&p, (int) set);
   }
   return tables[z >> 3][(unsigned char) c] & bit[z & 7];
}

#endif

//////////////////////////////////////////////////////////////////////////////
//
//                     Instantiated data structures
//
// This is an attempt to implement a templated data structure.
//
// Hash table: call stb_define_hash(TYPE,N,KEY,K1,K2,HASH,VALUE)
//     TYPE     -- will define a structure type containing the hash table
//     N        -- the name, will prefix functions named:
//                        N create
//                        N destroy
//                        N get
//                        N set, N add, N update,
//                        N remove
//     KEY      -- the type of the key. 'x == y' must be valid
//       K1,K2  -- keys never used by the app, used as flags in the hashtable
//       HASH   -- a piece of code ending with 'return' that hashes key 'k'
//     VALUE    -- the type of the value. 'x = y' must be valid
//
//  Note that stb_define_hash_base can be used to define more sophisticated
//  hash tables, e.g. those that make copies of the key or use special
//  comparisons (e.g. strcmp).

#define STB_(prefix,name)     stb__##prefix##name
#define STB__(prefix,name)    prefix##name
#define STB__use(x)           x
#define STB__skip(x)

#define stb_declare_hash(PREFIX,TYPE,N,KEY,VALUE) \
   typedef struct st_##TYPE TYPE;\
   PREFIX int STB__(N, init)(TYPE *h, int count);\
   PREFIX int STB__(N, memory_usage)(TYPE *h);\
   PREFIX TYPE * STB__(N, create)(void);\
   PREFIX TYPE * STB__(N, copy)(TYPE *h);\
   PREFIX void STB__(N, destroy)(TYPE *h);\
   PREFIX int STB__(N,get_flag)(TYPE *a, KEY k, VALUE *v);\
   PREFIX VALUE STB__(N,get)(TYPE *a, KEY k);\
   PREFIX int STB__(N, set)(TYPE *a, KEY k, VALUE v);\
   PREFIX int STB__(N, add)(TYPE *a, KEY k, VALUE v);\
   PREFIX int STB__(N, update)(TYPE*a,KEY k,VALUE v);\
   PREFIX int STB__(N, remove)(TYPE *a, KEY k, VALUE *v);

#define STB_nocopy(x)        (x)
#define STB_nodelete(x)      0
#define STB_nofields         
#define STB_nonullvalue(x)
#define STB_nullvalue(x)     x
#define STB_safecompare(x)   x
#define STB_nosafe(x)

#ifdef __GNUC__
#define STB__nogcc(x)
#else
#define STB__nogcc(x)  x
#endif

#define stb_define_hash_base(TYPE,FIELDS,N,LOAD_FACTOR,                       \
                             KEY,EMPTY,DEL,COPY,DISPOSE,SAFE,COMPARE,HASH,    \
                             VALUE,HASVNULL,VNULL)                            \
                                                                              \
typedef struct                                                                \
{                                                                             \
   KEY   k;                                                                   \
   VALUE v;                                                                   \
} STB_(N,_hashpair);                                                          \
                                                                              \
STB__nogcc( typedef struct st_##TYPE TYPE;  )                                 \
struct st_##TYPE {                                                            \
   FIELDS                                                                     \
   STB_(N,_hashpair) *table;                                                  \
   unsigned int mask;                                                         \
   int count, limit;                                                          \
   int deleted;                                                               \
                                                                              \
   int delete_threshhold;                                                     \
   int grow_threshhold;                                                       \
   int shrink_threshhold;                                                     \
   unsigned char alloced, has_empty, has_del;                                 \
   VALUE ev; VALUE dv;                                                        \
};                                                                            \
                                                                              \
static unsigned int STB_(N, hash)(KEY k)                                      \
{                                                                             \
   HASH                                                                       \
}                                                                             \
                                                                              \
int STB__(N, init)(TYPE *h, int count)                                        \
{                                                                             \
   int i;                                                                     \
   if (count < 4) count = 4;                                                  \
   h->limit = count;                                                          \
   h->count = 0;                                                              \
   h->mask  = count-1;                                                        \
   h->deleted = 0;                                                            \
   h->grow_threshhold = (int) (count * LOAD_FACTOR);                          \
   h->has_empty = h->has_del = 0;                                             \
   h->alloced = 0;                                                            \
   if (count <= 64)                                                           \
      h->shrink_threshhold = 0;                                               \
   else                                                                       \
      h->shrink_threshhold = (int) (count * (LOAD_FACTOR/2.25));              \
   h->delete_threshhold = (int) (count * (1-LOAD_FACTOR)/2);                  \
   h->table = (STB_(N,_hashpair)*) malloc(sizeof(h->table[0]) * count);       \
   if (h->table == NULL) return 0;                                            \
   /* ideally this gets turned into a memset32 automatically */               \
   for (i=0; i < count; ++i)                                                  \
      h->table[i].k = EMPTY;                                                  \
   return 1;                                                                  \
}                                                                             \
                                                                              \
int STB__(N, memory_usage)(TYPE *h)                                           \
{                                                                             \
   return sizeof(*h) + h->limit * sizeof(h->table[0]);                        \
}                                                                             \
                                                                              \
TYPE * STB__(N, create)(void)                                                 \
{                                                                             \
   TYPE *h = (TYPE *) malloc(sizeof(*h));                                     \
   if (h) {                                                                   \
      if (STB__(N, init)(h, 16))                                              \
         h->alloced = 1;                                                      \
      else { free(h); h=NULL; }                                               \
   }                                                                          \
   return h;                                                                  \
}                                                                             \
                                                                              \
void STB__(N, destroy)(TYPE *a)                                               \
{                                                                             \
   int i;                                                                     \
   for (i=0; i < a->limit; ++i)                                               \
      if (a->table[i].k != EMPTY && a->table[i].k != DEL)                     \
         DISPOSE(a->table[i].k);                                              \
   free(a->table);                                                            \
   if (a->alloced)                                                            \
      free(a);                                                                \
}                                                                             \
                                                                              \
static void STB_(N, rehash)(TYPE *a, int count);                              \
                                                                              \
int STB__(N,get_flag)(TYPE *a, KEY k, VALUE *v)                               \
{                                                                             \
   unsigned int h = STB_(N, hash)(k);                                         \
   unsigned int n = h & a->mask, s;                                           \
   if (k == EMPTY) { if (a->has_empty) *v = a->ev; return a->has_empty; }     \
   if (k == DEL  ) { if (a->has_del  ) *v = a->dv; return a->has_del;   }     \
   if (a->table[n].k==EMPTY) return 0;                                        \
   SAFE(if (a->table[n].k != DEL))                                            \
   if (COMPARE(a->table[n].k,k)) { *v = a->table[n].v; return 1; }            \
   s = stb_rehash(h) | 1;                                                     \
   for(;;) {                                                                  \
      n = (n + s) & a->mask;                                                  \
      if (a->table[n].k==EMPTY) return 0;                                     \
      SAFE(if (a->table[n].k == DEL) continue;)                               \
      if (COMPARE(a->table[n].k,k))                                           \
         { *v = a->table[n].v; return 1; }                                    \
   }                                                                          \
}                                                                             \
                                                                              \
HASVNULL(                                                                     \
   VALUE STB__(N,get)(TYPE *a, KEY k)                                         \
   {                                                                          \
      VALUE v;                                                                \
      if (STB__(N,get_flag)(a,k,&v)) return v;                                \
      else                           return VNULL;                            \
   }                                                                          \
)                                                                             \
                                                                              \
int STB__(N,getkey)(TYPE *a, KEY k, KEY *kout)                                \
{                                                                             \
   unsigned int h = STB_(N, hash)(k);                                         \
   unsigned int n = h & a->mask, s;                                           \
   if (k == EMPTY || k == DEL) return 0;                                      \
   if (a->table[n].k==EMPTY) return 0;                                        \
   SAFE(if (a->table[n].k != DEL))                                            \
   if (COMPARE(a->table[n].k,k)) { *kout = a->table[n].k; return 1; }         \
   s = stb_rehash(h) | 1;                                                     \
   for(;;) {                                                                  \
      n = (n + s) & a->mask;                                                  \
      if (a->table[n].k==EMPTY) return 0;                                     \
      SAFE(if (a->table[n].k == DEL) continue;)                               \
      if (COMPARE(a->table[n].k,k))                                           \
         { *kout = a->table[n].k; return 1; }                                 \
   }                                                                          \
}                                                                             \
                                                                              \
static int STB_(N,addset)(TYPE *a, KEY k, VALUE v,                            \
                             int allow_new, int allow_old, int copy)          \
{                                                                             \
   unsigned int h = STB_(N, hash)(k);                                         \
   unsigned int n = h & a->mask;                                              \
   int b = -1;                                                                \
   if (k == EMPTY)                                                            \
      if (a->has_empty ? allow_old : allow_new) {                             \
          n=a->has_empty; a->ev = v; a->has_empty = 1; return !n;             \
      } else return 0;                                                        \
   if (k == DEL)                                                              \
      if (a->has_del ? allow_old : allow_new) {                               \
          n=a->has_del; a->dv = v; a->has_del = 1; return !n;                 \
      } else return 0;                                                        \
   if (a->table[n].k != EMPTY) {                                              \
      unsigned int s;                                                         \
      if (a->table[n].k == DEL)                                               \
         b = n;                                                               \
      else if (COMPARE(a->table[n].k,k)) {                                    \
         if (allow_old)                                                       \
            a->table[n].v = v;                                                \
         return !allow_new;                                                   \
      }                                                                       \
      s = stb_rehash(h) | 1;                                                  \
      for(;;) {                                                               \
         n = (n + s) & a->mask;                                               \
         if (a->table[n].k == EMPTY) break;                                   \
         if (a->table[n].k == DEL) {                                          \
            if (b < 0) b = n;                                                 \
         } else if (COMPARE(a->table[n].k,k)) {                               \
            if (allow_old)                                                    \
               a->table[n].v = v;                                             \
            return !allow_new;                                                \
         }                                                                    \
      }                                                                       \
   }                                                                          \
   if (!allow_new) return 0;                                                  \
   if (b < 0) b = n; else --a->deleted;                                       \
   a->table[b].k = copy ? COPY(k) : k;                                        \
   a->table[b].v = v;                                                         \
   ++a->count;                                                                \
   if (a->count > a->grow_threshhold)                                         \
      STB_(N,rehash)(a, a->limit*2);                                          \
   return 1;                                                                  \
}                                                                             \
                                                                              \
int STB__(N, set)(TYPE *a, KEY k, VALUE v){return STB_(N,addset)(a,k,v,1,1,1);}\
int STB__(N, add)(TYPE *a, KEY k, VALUE v){return STB_(N,addset)(a,k,v,1,0,1);}\
int STB__(N, update)(TYPE*a,KEY k,VALUE v){return STB_(N,addset)(a,k,v,0,1,1);}\
                                                                              \
int STB__(N, remove)(TYPE *a, KEY k, VALUE *v)                                \
{                                                                             \
   unsigned int h = STB_(N, hash)(k);                                         \
   unsigned int n = h & a->mask, s;                                           \
   if (k == EMPTY) { if (a->has_empty) { if(v)*v = a->ev; a->has_empty=0; return 1; } return 0; } \
   if (k == DEL  ) { if (a->has_del  ) { if(v)*v = a->dv; a->has_del  =0; return 1; } return 0; } \
   if (a->table[n].k == EMPTY) return 0;                                      \
   if (SAFE(a->table[n].k == DEL || ) !COMPARE(a->table[n].k,k)) {            \
      s = stb_rehash(h) | 1;                                                  \
      for(;;) {                                                               \
         n = (n + s) & a->mask;                                               \
         if (a->table[n].k == EMPTY) return 0;                                \
         SAFE(if (a->table[n].k == DEL) continue;)                            \
         if (COMPARE(a->table[n].k,k)) break;                                 \
      }                                                                       \
   }                                                                          \
   DISPOSE(a->table[n].k);                                                    \
   a->table[n].k = DEL;                                                       \
   --a->count;                                                                \
   ++a->deleted;                                                              \
   if (v != NULL)                                                             \
      *v = a->table[n].v;                                                     \
   if (a->count < a->shrink_threshhold)                                       \
      STB_(N, rehash)(a, a->limit >> 1);                                      \
   else if (a->deleted > a->delete_threshhold)                                \
      STB_(N, rehash)(a, a->limit);                                           \
   return 1;                                                                  \
}                                                                             \
                                                                              \
TYPE * STB__(N, copy)(TYPE *a)                                                \
{                                                                             \
   int i;                                                                     \
   TYPE *h = (TYPE *) malloc(sizeof(*h));                                     \
   if (!h) return NULL;                                                       \
   if (!STB__(N, init)(h, a->count)) { free(h); return NULL; }                \
   h->count = a->count;                                                       \
   h->deleted = a->deleted;                                                   \
   h->alloced = 1;                                                            \
   h->ev = a->ev; h->dv = a->dv;                                              \
   h->has_empty = a->has_empty; h->has_del = a->has_del;                      \
   memcpy(h->table, a->table, h->limit * sizeof(h->table[0]));                \
   for (i=0; i < a->limit; ++i)                                               \
      if (h->table[i].k != EMPTY && h->table[i].k != DEL)                     \
         h->table[i].k = COPY(h->table[i].k);                                 \
   return h;                                                                  \
}                                                                             \
                                                                              \
static void STB_(N, rehash)(TYPE *a, int count)                               \
{                                                                             \
   int i;                                                                     \
   TYPE b;                                                                    \
   STB__(N, init)(&b, count);                                                 \
   for (i=0; i < a->limit; ++i)                                               \
      if (a->table[i].k != EMPTY && a->table[i].k != DEL)                     \
         STB_(N,addset)(&b, a->table[i].k, a->table[i].v,1,1,0);              \
   free(a->table);                                                            \
   a->table = b.table;\
   a->mask = b.mask;\
   a->count = b.count;\
   a->limit = b.limit;\
   a->deleted = b.deleted;\
   a->delete_threshhold = b.delete_threshhold;\
   a->grow_threshhold = b.grow_threshhold;\
   a->shrink_threshhold = b.shrink_threshhold;\
}

#define STB_equal(a,b)  ((a) == (b))

#define stb_define_hash(TYPE,N,KEY,EMPTY,DEL,HASH,VALUE)                      \
   stb_define_hash_base(TYPE,STB_nofields,N,0.85f,                            \
              KEY,EMPTY,DEL,STB_nocopy,STB_nodelete,STB_nosafe,STB_equal,HASH,\
              VALUE,STB_nonullvalue,0)

//////////////////////////////////////////////////////////////////////////////
//
//                        stb_ptrmap
//
// An stb_ptrmap data structure is an O(1) hash table between pointers. One
// application is to let you store "extra" data associated with pointers,
// which is why it was originally called stb_extra.

stb_declare_hash(STB_EXTERN, stb_ptrmap, stb_ptrmap_, void *, void *)
stb_declare_hash(STB_EXTERN, stb_idict, stb_idict_, stb_int32, stb_int32)

STB_EXTERN void        stb_ptrmap_delete(stb_ptrmap *e, void (*free_func)(void *));
STB_EXTERN stb_ptrmap *stb_ptrmap_new(void);

STB_EXTERN stb_idict * stb_idict_new_size(int size);
STB_EXTERN void        stb_idict_remove_all(stb_idict *e);

#ifdef STB_DEFINE

#define STB_EMPTY ((void *) 2)
#define STB_EDEL  ((void *) 6)

stb_define_hash_base(stb_ptrmap, STB_nofields, stb_ptrmap_,0.85f,       
              void *,STB_EMPTY,STB_EDEL,STB_nocopy,STB_nodelete,STB_nosafe,STB_equal,return stb_hashptr(k);,
              void *,STB_nullvalue,NULL)

stb_ptrmap *stb_ptrmap_new(void)
{
   return stb_ptrmap_create();
}

void stb_ptrmap_delete(stb_ptrmap *e, void (*free_func)(void *))
{
   int i;
   if (free_func)
      for (i=0; i < e->limit; ++i)
         if (e->table[i].k != STB_EMPTY && e->table[i].k != STB_EDEL)
            if (free_func == free)
               free(e->table[i].v); // allow STB_MALLOC_WRAPPER to operate
            else
               free_func(e->table[i].v);
   stb_ptrmap_destroy(e);
}

// extra fields needed for stua_dict
#define STB_IEMPTY  ((int) 1)
#define STB_IDEL    ((int) 3)
stb_define_hash_base(stb_idict, short type; short gc; STB_nofields, stb_idict_,0.85f,
              stb_int32,STB_IEMPTY,STB_IDEL,STB_nocopy,STB_nodelete,STB_nosafe,STB_equal,
              return stb_rehash_improved(k);,stb_int32,STB_nonullvalue,0)

stb_idict * stb_idict_new_size(int size)
{
   stb_idict *e = (stb_idict *) malloc(sizeof(*e));
   if (e) {
      if (!stb_is_pow2(size))
         size = 1 << stb_log2_ceil(size);
      stb_idict_init(e, size);
      e->alloced = 1;
   }
   return e;
}

void stb_idict_remove_all(stb_idict *e)
{
   int n;
   for (n=0; n < e->limit; ++n)
      e->table[n].k = STB_IEMPTY;
   e->has_empty = e->has_del = 0;
}
#endif



//////////////////////////////////////////////////////////////////////////////
//
//                  SDICT: Hash Table for Strings (symbol table)
//
//           if "use_arena=1", then strings will be copied
//           into blocks and never freed until the sdict is freed;
//           otherwise they're malloc()ed and free()d on the fly. 
//           (specify use_arena=1 if you never stb_sdict_remove)

stb_declare_hash(STB_EXTERN, stb_sdict, stb_sdict_, char *, void *)

STB_EXTERN stb_sdict * stb_sdict_new(int use_arena);
STB_EXTERN void        stb_sdict_delete(stb_sdict *);
STB_EXTERN void *      stb_sdict_change(stb_sdict *, char *str, void *p);
STB_EXTERN int         stb_sdict_count(stb_sdict *d);

#define stb_sdict_for(d,i,q,z)                                          \
   for(i=0; i < (d)->limit ? q=(d)->table[i].k,z=(d)->table[i].v,1 : 0; ++i)    \
      if (q==NULL||q==(void *) 1);else   // reversed makes macro friendly

#ifdef STB_DEFINE

#define STB_DEL ((void *) 1)
#define STB_SDEL  ((char *) 1)

#define stb_sdict__copy(x)                                       \
   strcpy(a->arena ? stb_malloc_string(a->arena, strlen(x)+1)    \
                   : (char *) malloc(strlen(x)+1), x)

#define stb_sdict__dispose(x)  if (!a->arena) free(x)

stb_define_hash_base(stb_sdict, void*arena;, stb_sdict_, 0.85f,
        char *, NULL, STB_SDEL, stb_sdict__copy, stb_sdict__dispose,
                        STB_safecompare, !strcmp, return stb_hash(k);,
        void *, STB_nullvalue, NULL)

int stb_sdict_count(stb_sdict *a)
{
   return a->count;
}

stb_sdict * stb_sdict_new(int use_arena)
{
   stb_sdict *d = stb_sdict_create();
   if (d == NULL) return NULL;
   d->arena = use_arena ? stb_malloc_global(1) : NULL;
   return d;
}

void stb_sdict_delete(stb_sdict *d)
{
   if (d->arena)
      stb_free(d->arena);
   stb_sdict_destroy(d);
}

void * stb_sdict_change(stb_sdict *d, char *str, void *p)
{
   void *q = stb_sdict_get(d, str);
   stb_sdict_set(d, str, p);
   return q;
}
#endif

//////////////////////////////////////////////////////////////////////////////
//
//                     Instantiated data structures
//
// This is an attempt to implement a templated data structure.
// What you do is define a struct foo, and then include several
// pointer fields to struct foo in your struct. Then you call
// the instantiator, which creates the functions that implement
// the data structure. This requires massive undebuggable #defines,
// so we limit the cases where we do this.
//
// AA tree is an encoding of a 2-3 tree whereas RB trees encode a 2-3-4 tree;
// much simpler code due to fewer cases.

#define stb__bst_parent(x)    x
#define stb__bst_noparent(x)

#define stb_bst_fields(N)                                   \
    *STB_(N,left), *STB_(N,right);                          \
    unsigned char STB_(N,level)

#define stb_bst_fields_parent(N)                            \
    *STB_(N,left), *STB_(N,right),  *STB_(N,parent);        \
    unsigned char STB_(N,level)

#define STB__level(N,x)         ((x) ? (x)->STB_(N,level) : 0)

#define stb_bst_base(TYPE, N, TREE, M, compare, PAR)                         \
                                                                             \
static int STB_(N,_compare)(TYPE *p, TYPE *q)                                \
{                                                                            \
   compare                                                                   \
}                                                                            \
                                                                             \
static void STB_(N,setleft)(TYPE *q, TYPE *v)                                \
{                                                                            \
   q->STB_(N,left) = v;                                                      \
   PAR(if (v) v->STB_(N,parent) = q;)                                        \
}                                                                            \
                                                                             \
static void STB_(N,setright)(TYPE *q, TYPE *v)                               \
{                                                                            \
   q->STB_(N,right) = v;                                                     \
   PAR(if (v) v->STB_(N,parent) = q;)                                        \
}                                                                            \
                                                                             \
static TYPE *STB_(N,skew)(TYPE *q)                                           \
{                                                                            \
   if (q == NULL) return q;                                                  \
   if (q->STB_(N,left)                                                       \
        && q->STB_(N,left)->STB_(N,level) == q->STB_(N,level)) {             \
      TYPE *p       = q->STB_(N,left);                                       \
      STB_(N,setleft)(q, p->STB_(N,right));                                  \
      STB_(N,setright)(p, q);                                                \
      return p;                                                              \
   }                                                                         \
   return q;                                                                 \
}                                                                            \
                                                                             \
static TYPE *STB_(N,split)(TYPE *p)                                          \
{                                                                            \
   TYPE *q = p->STB_(N,right);                                               \
   if (q && q->STB_(N,right)                                                 \
         && q->STB_(N,right)->STB_(N,level) == p->STB_(N,level)) {           \
      STB_(N,setright)(p, q->STB_(N,left));                                  \
      STB_(N,setleft)(q,p);                                                  \
      ++q->STB_(N,level);                                                    \
      return q;                                                              \
   }                                                                         \
   return p;                                                                 \
}                                                                            \
                                                                             \
TYPE *STB__(N,insert)(TYPE *tree, TYPE *item)                                \
{                                                                            \
   int c;                                                                    \
   if (tree == NULL) {                                                       \
      item->STB_(N,left) = NULL;                                             \
      item->STB_(N,right) = NULL;                                            \
      item->STB_(N,level) = 1;                                               \
      PAR(item->STB_(N,parent) = NULL;)                                      \
      return item;                                                           \
   }                                                                         \
   c = STB_(N,_compare)(item,tree);                                          \
   if (c == 0) {                                                             \
      if (item != tree) {                                                    \
         STB_(N,setleft)(item, tree->STB_(N,left));                          \
         STB_(N,setright)(item, tree->STB_(N,right));                        \
         item->STB_(N,level) = tree->STB_(N,level);                          \
         PAR(item->STB_(N,parent) = NULL;)                                   \
      }                                                                      \
      return item;                                                           \
   }                                                                         \
   if (c < 0)                                                                \
      STB_(N,setleft )(tree, STB__(N,insert)(tree->STB_(N,left), item));     \
   else                                                                      \
      STB_(N,setright)(tree, STB__(N,insert)(tree->STB_(N,right), item));    \
   tree = STB_(N,skew)(tree);                                                \
   tree = STB_(N,split)(tree);                                               \
   PAR(tree->STB_(N,parent) = NULL;)                                         \
   return tree;                                                              \
}                                                                            \
                                                                             \
TYPE *STB__(N,remove)(TYPE *tree, TYPE *item)                                \
{                                                                            \
   static TYPE *delnode, *leaf, *restore;                                    \
   if (tree == NULL) return NULL;                                            \
   leaf = tree;                                                              \
   if (STB_(N,_compare)(item, tree) < 0) {                                   \
      STB_(N,setleft)(tree, STB__(N,remove)(tree->STB_(N,left), item));      \
   } else {                                                                  \
      TYPE *r;                                                               \
      delnode = tree;                                                        \
      r = STB__(N,remove)(tree->STB_(N,right), item);                        \
      /* maybe move 'leaf' up to this location */                            \
      if (restore == tree) { tree = leaf; leaf = restore = NULL;  }          \
      STB_(N,setright)(tree,r);                                              \
      assert(tree->STB_(N,right) != tree);                                   \
   }                                                                         \
   if (tree == leaf) {                                                       \
      if (delnode == item) {                                                 \
         tree = tree->STB_(N,right);                                         \
         assert(leaf->STB_(N,left) == NULL);                                 \
         /* move leaf (the right sibling) up to delnode */                   \
         STB_(N,setleft )(leaf, item->STB_(N,left ));                        \
         STB_(N,setright)(leaf, item->STB_(N,right));                        \
         leaf->STB_(N,level) = item->STB_(N,level);                          \
         if (leaf != item)                                                   \
            restore = delnode;                                               \
      }                                                                      \
      delnode = NULL;                                                        \
   } else {                                                                  \
      if (STB__level(N,tree->STB_(N,left) ) < tree->STB_(N,level)-1 ||       \
          STB__level(N,tree->STB_(N,right)) < tree->STB_(N,level)-1) {       \
         --tree->STB_(N,level);                                              \
         if (STB__level(N,tree->STB_(N,right)) > tree->STB_(N,level))        \
            tree->STB_(N,right)->STB_(N,level) = tree->STB_(N,level);        \
         tree = STB_(N,skew)(tree);                                          \
         STB_(N,setright)(tree, STB_(N,skew)(tree->STB_(N,right)));          \
         if (tree->STB_(N,right))                                            \
            STB_(N,setright)(tree->STB_(N,right),                            \
                  STB_(N,skew)(tree->STB_(N,right)->STB_(N,right)));         \
         tree = STB_(N,split)(tree);                                         \
         if (tree->STB_(N,right))                                            \
            STB_(N,setright)(tree,  STB_(N,split)(tree->STB_(N,right)));     \
      }                                                                      \
   }                                                                         \
   PAR(if (tree) tree->STB_(N,parent) = NULL;)                               \
   return tree;                                                              \
}                                                                            \
                                                                             \
TYPE *STB__(N,last)(TYPE *tree)                                              \
{                                                                            \
   if (tree)                                                                 \
      while (tree->STB_(N,right)) tree = tree->STB_(N,right);                \
   return tree;                                                              \
}                                                                            \
                                                                             \
TYPE *STB__(N,first)(TYPE *tree)                                             \
{                                                                            \
   if (tree)                                                                 \
      while (tree->STB_(N,left)) tree = tree->STB_(N,left);                  \
   return tree;                                                              \
}                                                                            \
                                                                             \
TYPE *STB__(N,next)(TYPE *tree, TYPE *item)                                  \
{                                                                            \
   TYPE *next = NULL;                                                        \
   if (item->STB_(N,right))                                                  \
      return STB__(N,first)(item->STB_(N,right));                            \
   PAR(                                                                      \
      while(item->STB_(N,parent)) {                                          \
         TYPE *up = item->STB_(N,parent);                                    \
         if (up->STB_(N,left) == item) return up;                            \
         item = up;                                                          \
      }                                                                      \
      return NULL;                                                           \
   )                                                                         \
   while (tree != item) {                                                    \
      if (STB_(N,_compare)(item, tree) < 0) {                                \
         next = tree;                                                        \
         tree = tree->STB_(N,left);                                          \
      } else {                                                               \
         tree = tree->STB_(N,right);                                         \
      }                                                                      \
   }                                                                         \
   return next;                                                              \
}                                                                            \
                                                                             \
TYPE *STB__(N,prev)(TYPE *tree, TYPE *item)                                  \
{                                                                            \
   TYPE *next = NULL;                                                        \
   if (item->STB_(N,left))                                                   \
      return STB__(N,last)(item->STB_(N,left));                              \
   PAR(                                                                      \
      while(item->STB_(N,parent)) {                                          \
         TYPE *up = item->STB_(N,parent);                                    \
         if (up->STB_(N,right) == item) return up;                           \
         item = up;                                                          \
      }                                                                      \
      return NULL;                                                           \
   )                                                                         \
   while (tree != item) {                                                    \
      if (STB_(N,_compare)(item, tree) < 0) {                                \
         tree = tree->STB_(N,left);                                          \
      } else {                                                               \
         next = tree;                                                        \
         tree = tree->STB_(N,right);                                         \
      }                                                                      \
   }                                                                         \
   return next;                                                              \
}                                                                            \
                                                                             \
STB__DEBUG(                                                                  \
   void STB__(N,_validate)(TYPE *tree, int root)                             \
   {                                                                         \
      if (tree == NULL) return;                                              \
      PAR(if(root) assert(tree->STB_(N,parent) == NULL);)                    \
      assert(STB__level(N,tree->STB_(N,left) ) == tree->STB_(N,level)-1);    \
      assert(STB__level(N,tree->STB_(N,right)) <= tree->STB_(N,level));      \
      assert(STB__level(N,tree->STB_(N,right)) >= tree->STB_(N,level)-1);    \
      if (tree->STB_(N,right)) {                                             \
        assert(STB__level(N,tree->STB_(N,right)->STB_(N,right))              \
                                               !=    tree->STB_(N,level));   \
        PAR(assert(tree->STB_(N,right)->STB_(N,parent) == tree);)            \
      }                                                                      \
      PAR(if(tree->STB_(N,left)) assert(tree->STB_(N,left)->STB_(N,parent) == tree);) \
      STB__(N,_validate)(tree->STB_(N,left) ,0);                             \
      STB__(N,_validate)(tree->STB_(N,right),0);                             \
   }                                                                         \
)                                                                            \
                                                                             \
typedef struct                                                               \
{                                                                            \
   TYPE *root;                                                               \
} TREE;                                                                      \
                                                                             \
void  STB__(M,Insert)(TREE *tree, TYPE *item)                                \
{ tree->root = STB__(N,insert)(tree->root, item); }                          \
void  STB__(M,Remove)(TREE *tree, TYPE *item)                                \
{ tree->root = STB__(N,remove)(tree->root, item); }                          \
TYPE *STB__(M,Next)(TREE *tree, TYPE *item)                                  \
{ return STB__(N,next)(tree->root, item); }                                  \
TYPE *STB__(M,Prev)(TREE *tree, TYPE *item)                                  \
{ return STB__(N,prev)(tree->root, item); }                                  \
TYPE *STB__(M,First)(TREE *tree) { return STB__(N,first)(tree->root); }      \
TYPE *STB__(M,Last) (TREE *tree) { return STB__(N,last) (tree->root); }      \
void STB__(M,Init)(TREE *tree) { tree->root = NULL; }


#define stb_bst_find(N,tree,fcompare)                                        \
{                                                                            \
   int c;                                                                    \
   while (tree != NULL) {                                                    \
      fcompare                                                               \
      if (c == 0) return tree;                                               \
      if (c < 0)  tree = tree->STB_(N,left);                                 \
      else        tree = tree->STB_(N,right);                                \
   }                                                                         \
   return NULL;                                                              \
}

#define stb_bst_raw(TYPE,N,TREE,M,vfield,VTYPE,compare,PAR)                  \
   stb_bst_base(TYPE,N,TREE,M,                                               \
         VTYPE a = p->vfield; VTYPE b = q->vfield; return (compare);, PAR )  \
                                                                             \
TYPE *STB__(N,find)(TYPE *tree, VTYPE a)                                     \
   stb_bst_find(N,tree,VTYPE b = tree->vfield; c = (compare);)               \
TYPE *STB__(M,Find)(TREE *tree, VTYPE a)                                     \
{ return STB__(N,find)(tree->root, a); }

#define stb_bst(TYPE,N,TREE,M,vfield,VTYPE,compare) \
   stb_bst_raw(TYPE,N,TREE,M,vfield,VTYPE,compare,stb__bst_noparent)
#define stb_bst_parent(TYPE,N,TREE,M,vfield,VTYPE,compare) \
   stb_bst_raw(TYPE,N,TREE,M,vfield,VTYPE,compare,stb__bst_parent)



//////////////////////////////////////////////////////////////////////////////
//
//                             File Processing
//


#ifdef _MSC_VER
  // if not win32, we can still get gcc style int64!
  typedef unsigned _int64 stb__64;
   
  #define stb_rename(x,y)   _wrename(stb__from_utf8(x), stb__from_utf8_alt(y))
  #define stb_mktemp   _mktemp
  STB_EXTERN void     stb_fput_varlen64(FILE *f, stb__64 v);
  STB_EXTERN stb__64  stb_fget_varlen64(FILE *f);
  STB_EXTERN int      stb_size_varlen64(stb__64 v);
#else
  #define stb_mktemp   mktemp
  #define stb_rename   rename
#endif


#define stb_filec    (char *) stb_file
#define stb_fileu    (unsigned char *) stb_file
STB_EXTERN void *  stb_file(char *filename, size_t *length);
STB_EXTERN size_t  stb_filelen(FILE *f);
STB_EXTERN int     stb_filewrite(char *filename, void *data, size_t length);
STB_EXTERN int     stb_filewritestr(char *filename, char *data);
STB_EXTERN char ** stb_stringfile(char *filename, int *len);
STB_EXTERN char ** stb_stringfile_trimmed(char *name, int *len, char comm);
STB_EXTERN char *  stb_fgets(char *buffer, int buflen, FILE *f);
STB_EXTERN char *  stb_fgets_malloc(FILE *f);
STB_EXTERN int     stb_fexists(char *filename);

STB_EXTERN int     stb_fullpath(char *abs, int abs_size, char *rel);
STB_EXTERN FILE *  stb_fopen(char *filename, char *mode);
STB_EXTERN int     stb_fclose(FILE *f, int keep);

enum
{
   stb_keep_no = 0,
   stb_keep_yes = 1,
   stb_keep_if_different = 2,
};

STB_EXTERN int     stb_copyfile(char *src, char *dest);

#ifdef _MSC_VER
  // if not win32, we can still get gcc style int64!
  typedef unsigned __int64 stb__64;
  STB_EXTERN void     stb_fput_varlen64(FILE *f, stb__64 v);
  STB_EXTERN stb__64  stb_fget_varlen64(FILE *f);
  STB_EXTERN int      stb_size_varlen64(stb__64 v);
#endif

STB_EXTERN void    stb_fwrite32(FILE *f, stb_uint32 datum);
STB_EXTERN void    stb_fput_varlen (FILE *f, int v);
STB_EXTERN void    stb_fput_varlenu(FILE *f, unsigned int v);
STB_EXTERN int     stb_fget_varlen (FILE *f);
STB_EXTERN stb_uint stb_fget_varlenu(FILE *f);
STB_EXTERN void    stb_fput_ranged (FILE *f, int v, int b, stb_uint n);
STB_EXTERN int     stb_fget_ranged (FILE *f, int b, stb_uint n);
STB_EXTERN int     stb_size_varlen (int v);
STB_EXTERN int     stb_size_varlenu(unsigned int v);
STB_EXTERN int     stb_size_ranged (int b, stb_uint n);



#ifdef STB_DEFINE

void stb_fwrite32(FILE *f, uint32 x)
{
   fwrite(&x, 4, 1, f);
}

#ifdef _MSC_VER
   #define stb__stat   _stat
#else
   #define stb__stat   stat
#endif

int stb_fexists(char *filename)
{
   struct stb__stat buf;
   return stb__windows(
             _wstat(stb__from_utf8(filename), &buf),
               stat(filename,&buf)
          ) == 0;
}

size_t  stb_filelen(FILE *f)
{
   size_t len, pos;
   pos = ftell(f);
   fseek(f, 0, SEEK_END);
   len = ftell(f);
   fseek(f, pos, SEEK_SET);
   return len;
}

void *stb_file(char *filename, size_t *length)
{
   FILE *f = stb__fopen(filename, "rb");
   char *buffer;
   size_t len;
   if (!f) return NULL;
   len = stb_filelen(f);
   buffer = (char *) malloc(len+2); // nul + extra
   if (fread(buffer, 1, len, f) == len) {
      if (length) *length = len;
      buffer[len] = 0;
   } else {
      free(buffer);
      buffer = NULL;
   }
   fclose(f);
   return buffer;
}

int stb_filewrite(char *filename, void *data, size_t length)
{
   FILE *f = stb_fopen(filename, "wb");
   if (f) {
      fwrite(data, 1, length, f);
      stb_fclose(f, stb_keep_if_different);
   }
   return f != NULL;
}

int stb_filewritestr(char *filename, char *data)
{
   return stb_filewrite(filename, data, strlen(data));
}

void *  stb_file_max(char *filename, size_t *length)
{
   FILE *f = stb__fopen(filename, "rb");
   char *buffer;
   size_t len, maxlen;
   if (!f) return NULL;
   maxlen = *length;
   buffer = (char *) malloc(maxlen+1);
   len = fread(buffer, 1, maxlen, f);
   buffer[len] = 0;
   fclose(f);
   *length = len;
   return buffer;
}

char ** stb_stringfile(char *filename, int *plen)
{
   FILE *f = stb__fopen(filename, "rb");
   char *buffer, **list=NULL, *s;
   size_t len, count, i;

   if (!f) return NULL;
   len = stb_filelen(f);
   buffer = (char *) malloc(len+1);
   len = fread(buffer, 1, len, f);
   buffer[len] = 0;
   fclose(f);

   // two passes through: first time count lines, second time set them
   for (i=0; i < 2; ++i) {
      s = buffer;
      if (i == 1)
         list[0] = s;
      count = 1;
      while (*s) {
         if (*s == '\n' || *s == '\r') {
            // detect if both cr & lf are together
            int crlf = (s[0] + s[1]) == ('\n' + '\r');
            if (i == 1) *s = 0;
            if (crlf) ++s;
            if (s[1]) {  // it's not over yet
               if (i == 1) list[count] = s+1;
               ++count;
            }
         }
         ++s;
      }
      if (i == 0) {
         list = (char **) malloc(sizeof(*list) * (count+1) + len+1);
         if (!list) return NULL;
         list[count] = 0;
         // recopy the file so there's just a single allocation to free
         memcpy(&list[count+1], buffer, len+1);
         free(buffer);
         buffer = (char *) &list[count+1];
         if (plen) *plen = count;
      }
   }
   return list;
}

char ** stb_stringfile_trimmed(char *name, int *len, char comment)
{
   int i,n,o=0;
   char **s = stb_stringfile(name, &n);
   if (s == NULL) return NULL;
   for (i=0; i < n; ++i) {
      char *p = stb_skipwhite(s[i]);
      if (*p && *p != comment)
         s[o++] = p;
   }
   s[o] = NULL;
   if (len) *len = o;
   return s;
}

char * stb_fgets(char *buffer, int buflen, FILE *f)
{
   char *p;
   buffer[0] = 0;
   p = fgets(buffer, buflen, f);
   if (p) {
      int n = strlen(p)-1;
      if (n >= 0)
         if (p[n] == '\n')
            p[n] = 0;
   }
   return p;
}

char * stb_fgets_malloc(FILE *f)
{
   // avoid reallocing for small strings
   char quick_buffer[800];
   quick_buffer[sizeof(quick_buffer)-2] = 0;
   if (!fgets(quick_buffer, sizeof(quick_buffer), f))
      return NULL;

   if (quick_buffer[sizeof(quick_buffer)-2] == 0) {
      int n = strlen(quick_buffer);
      if (n > 0 && quick_buffer[n-1] == '\n')
         quick_buffer[n-1] = 0;
      return strdup(quick_buffer);
   } else {
      char *p;
      char *a = strdup(quick_buffer);
      int len = sizeof(quick_buffer)-1;

      while (!feof(f)) {
         if (a[len-1] == '\n') break;
         a = (char *) realloc(a, len*2);
         p = &a[len];
         p[len-2] = 0;
         if (!fgets(p, len, f))
            break;
         if (p[len-2] == 0) {
            len += strlen(p);
            break;
         }
         len = len + (len-1);
      }
      if (a[len-1] == '\n')
         a[len-1] = 0;
      return a;
   }
}

int stb_fullpath(char *abs, int abs_size, char *rel)
{
   #ifdef _MSC_VER
   return _fullpath(abs, rel, abs_size) != NULL;
   #else
   if (abs[0] == '/' || abs[0] == '~') {
      if ((int) strlen(rel) >= abs_size)
         return 0;
      strcpy(abs,rel);
      return TRUE;
   } else {
      int n;
      getcwd(abs, abs_size);
      n = strlen(abs);
      if (n+(int) strlen(rel)+2 <= abs_size) {
         abs[n] = '/';
         strcpy(abs+n+1, rel);
         return TRUE;
      } else {
         return FALSE;
      }
   }
   #endif
}

static int stb_fcmp_core(FILE *f, FILE *g)
{
   char buf1[1024],buf2[1024];
   int n1,n2, res=0;

   while (1) {
      n1 = fread(buf1, 1, sizeof(buf1), f);
      n2 = fread(buf2, 1, sizeof(buf2), g);
      res = memcmp(buf1,buf2,stb_min(n1,n2));
      if (res)
         break;
      if (n1 != n2) {
         res = n1 < n2 ? -1 : 1;
         break;
      }
      if (n1 == 0)
         break;
   }

   fclose(f);
   fclose(g);
   return res;
}

int stb_fcmp(char *s1, char *s2)
{
   FILE *f = stb__fopen(s1, "rb");
   FILE *g = stb__fopen(s2, "rb");

   if (f == NULL || g == NULL) {
      if (f) fclose(f);
      if (g) {
         fclose(g);
         return TRUE;
      }
      return f != NULL;
   }

   return stb_fcmp_core(f,g);
}

int stb_feq(char *s1, char *s2)
{
   FILE *f = stb__fopen(s1, "rb");
   FILE *g = stb__fopen(s2, "rb");

   if (f == NULL || g == NULL) {
      if (f) fclose(f);
      if (g) fclose(g);
      return f == g;
   }

   // feq is faster because it shortcuts if they're different length
   if (stb_filelen(f) != stb_filelen(g)) {
      fclose(f);
      fclose(g);
      return 0;
   }

   return !stb_fcmp_core(f,g);
}

static stb_ptrmap *stb__files;

typedef struct
{
   char *temp_name;
   char *name;
   int   errors;
} stb__file_data;

FILE *  stb_fopen(char *filename, char *mode)
{
   char name_full[4096];
   char temp_full[sizeof(name_full) + 12];
   int j,p;
   if (mode[0] != 'w' && !strchr(mode, '+'))
      return stb__fopen(filename, mode);

   // save away the full path to the file so if the program
   // changes the cwd everything still works right! unix has
   // better ways to do this, but we have to work in windows
   if (stb_fullpath(name_full, sizeof(name_full), filename)==0)
      return 0;

   // try to generate a temporary file in the same directory
   p = strlen(name_full)-1;
   while (p > 0 && name_full[p] != '/' && name_full[p] != '\\'
                && name_full[p] != ':' && name_full[p] != '~')
      --p;
   ++p;

   memcpy(temp_full, name_full, p);

   // try multiple times to make a temp file... just in
   // case some other process makes the name first
   for (j=0; j < 32; ++j) {
      FILE *f;
      strcpy(temp_full+p, "stmpXXXXXX");
      if (stb_mktemp(temp_full) == NULL)
         return 0;

      f = fopen(temp_full, mode);
      if (f != NULL) {
         stb__file_data *d = (stb__file_data *) malloc(sizeof(*d));
         if (!d) { assert(0);  /* NOTREACHED */fclose(f); return NULL; }
         if (stb__files == NULL) stb__files = stb_ptrmap_create();
         d->temp_name = strdup(temp_full);
         d->name      = strdup(name_full);
         d->errors    = 0;
         stb_ptrmap_add(stb__files, f, d);
         return f;
      }
   }

   return NULL;
}

int     stb_fclose(FILE *f, int keep)
{
   stb__file_data *d;

   int ok = FALSE;
   if (f == NULL) return 0;

   if (ferror(f))
      keep = stb_keep_no;

   fclose(f);

   if (stb__files && stb_ptrmap_remove(stb__files, f, (void **) &d)) {
      if (stb__files->count == 0) {
         stb_ptrmap_destroy(stb__files);
         stb__files = NULL;
      }
   } else
      return TRUE; // not special

   if (keep == stb_keep_if_different) {
      // check if the files are identical
      if (stb_feq(d->name, d->temp_name)) {
         keep = stb_keep_no;
         ok = TRUE;  // report success if no change
      }
   }

   if (keep != stb_keep_no) {
      if (stb_fexists(d->name) && remove(d->name)) {
         // failed to delete old, so don't keep new
         keep = stb_keep_no;
      } else {
         if (!stb_rename(d->temp_name, d->name))
            ok = TRUE;
         else
            keep=stb_keep_no;
      }
   }

   if (keep == stb_keep_no)
      remove(d->temp_name);

   free(d->temp_name);
   free(d->name);
   free(d);

   return ok;
}

int stb_copyfile(char *src, char *dest)
{
   char raw_buffer[1024];
   char *buffer;
   int buf_size = 65536;

   FILE *f, *g;

   // if file already exists at destination, do nothing
   if (stb_feq(src, dest)) return TRUE;

   // open file
   f = stb__fopen(src, "rb");
   if (f == NULL) return FALSE;

   // open file for writing
   g = stb__fopen(dest, "wb");
   if (g == NULL) {
      fclose(f);
      return FALSE;
   }

   buffer = (char *) malloc(buf_size);
   if (buffer == NULL) {
      buffer = raw_buffer;
      buf_size = sizeof(raw_buffer);
   }

   while (!feof(f)) {
      int n = fread(buffer, 1, buf_size, f);
      if (n != 0)
         fwrite(buffer, 1, n, g);
   }

   fclose(f);
   if (buffer != raw_buffer)
      free(buffer);

   fclose(g);
   return TRUE;
}

// varlen:
//    v' = (v >> 31) + (v < 0 ? ~v : v)<<1;  // small abs(v) => small v'
// output v as big endian v'+k for v' <= k:
//   1 byte :  v' <= 0x00000080          (  -64 <= v <   64)   7 bits
//   2 bytes:  v' <= 0x00004000          (-8192 <= v < 8192)  14 bits
//   3 bytes:  v' <= 0x00200000                               21 bits
//   4 bytes:  v' <= 0x10000000                               28 bits
// the number of most significant 1-bits in the first byte
// equals the number of bytes after the first

#define stb__varlen_xform(v)     (v<0 ? (~v << 1)+1 : (v << 1))

int stb_size_varlen(int v) { return stb_size_varlenu(stb__varlen_xform(v)); }
int stb_size_varlenu(unsigned int v)
{
   if (v < 0x00000080) return 1;
   if (v < 0x00004000) return 2;
   if (v < 0x00200000) return 3;
   if (v < 0x10000000) return 4;
   return 5;
}

void    stb_fput_varlen(FILE *f, int v) { stb_fput_varlenu(f, stb__varlen_xform(v)); }

void    stb_fput_varlenu(FILE *f, unsigned int z)
{
   if (z >= 0x10000000) fputc(0xF0,f);
   if (z >= 0x00200000) fputc((z < 0x10000000 ? 0xE0 : 0)+(z>>24),f);
   if (z >= 0x00004000) fputc((z < 0x00200000 ? 0xC0 : 0)+(z>>16),f);
   if (z >= 0x00000080) fputc((z < 0x00004000 ? 0x80 : 0)+(z>> 8),f);
   fputc(z,f);
}

#define stb_fgetc(f)    ((unsigned char) fgetc(f))

int     stb_fget_varlen(FILE *f)
{
   unsigned int z = stb_fget_varlenu(f);
   return (z & 1) ? ~(z>>1) : (z>>1);
}

unsigned int stb_fget_varlenu(FILE *f)
{
   unsigned int z;
   unsigned char d;
   d = stb_fgetc(f);

   if (d >= 0x80) {
      if (d >= 0xc0) {
         if (d >= 0xe0) {
            if (d == 0xf0) z = stb_fgetc(f) << 24;
            else           z = (d - 0xe0) << 24;
            z += stb_fgetc(f) << 16;
         }
         else
            z = (d - 0xc0) << 16;
         z += stb_fgetc(f) << 8;
      } else
         z = (d - 0x80) <<  8;
      z += stb_fgetc(f);
   } else
      z = d;
   return z;
}

#ifdef _MSC_VER

stb__64   stb_fget_varlen64(FILE *f)
{
   stb__64 z;
   unsigned char d;
   d = stb_fgetc(f);

   if (d >= 0x80) {
      if (d >= 0xc0) {
         if (d >= 0xe0) {
            if (d >= 0xf0) {
               if (d >= 0xf8) {
                  if (d >= 0xfc) {
                     if (d >= 0xfe) {
                        if (d >= 0xff)
                           z = (stb__64) stb_fgetc(f) << 56;
                        else
                           z = (stb__64) (d - 0xfe) << 56;
                        z |= (stb__64) stb_fgetc(f) << 48;
                     } else z = (stb__64) (d - 0xfc) << 48;
                     z |= (stb__64) stb_fgetc(f) << 40;
                  } else z = (stb__64) (d - 0xf8) << 40;
                  z |= (stb__64) stb_fgetc(f) << 32;
               } else z = (stb__64) (d - 0xf0) << 32;
               z |= (stb_uint) stb_fgetc(f) << 24;
            } else z = (stb_uint) (d - 0xe0) << 24;
            z |= (stb_uint) stb_fgetc(f) << 16;
         } else z = (stb_uint) (d - 0xc0) << 16;
         z |= (stb_uint) stb_fgetc(f) << 8;
      } else z = (stb_uint) (d - 0x80) << 8;
      z |= stb_fgetc(f);
   } else
      z = d;

   return (z & 1) ? ~(z >> 1) : (z >> 1);
}

int stb_size_varlen64(stb__64 v)
{
   if (v < 0x00000080) return 1;
   if (v < 0x00004000) return 2;
   if (v < 0x00200000) return 3;
   if (v < 0x10000000) return 4;
   if (v < 0x0000000800000000i64) return 5;
   if (v < 0x0000040000000000i64) return 6;
   if (v < 0x0002000000000000i64) return 7;
   if (v < 0x0100000000000000i64) return 8;
   return 9;
}

void    stb_fput_varlen64(FILE *f, stb__64 v)
{
   stb__64 z = stb__varlen_xform(v);
   int first=1;
   if (z >= 0x100000000000000i64) {
      fputc(0xff,f);
      first=0;
   }
   if (z >= 0x02000000000000i64) fputc((first ? 0xFE : 0)+(int)(z>>56),f), first=0;
   if (z >= 0x00040000000000i64) fputc((first ? 0xFC : 0)+(int)(z>>48),f), first=0;
   if (z >= 0x00000800000000i64) fputc((first ? 0xF8 : 0)+(int)(z>>40),f), first=0;
   if (z >= 0x00000010000000i64) fputc((first ? 0xF0 : 0)+(int)(z>>32),f), first=0;
   if (z >= 0x00000000200000i64) fputc((first ? 0xE0 : 0)+(int)(z>>24),f), first=0;
   if (z >= 0x00000000004000i64) fputc((first ? 0xC0 : 0)+(int)(z>>16),f), first=0;
   if (z >= 0x00000000000080i64) fputc((first ? 0x80 : 0)+(int)(z>> 8),f), first=0;
   fputc((int)z,f);
}
#endif

void    stb_fput_ranged(FILE *f, int v, int b, stb_uint n)
{
   v -= b;
   if (n <= (1 << 31))
      assert((stb_uint) v < n);
   if (n > (1 << 24)) fputc(v >> 24, f);
   if (n > (1 << 16)) fputc(v >> 16, f);
   if (n > (1 <<  8)) fputc(v >>  8, f);
   fputc(v,f);
}

int     stb_fget_ranged(FILE *f, int b, stb_uint n)
{
   unsigned int v=0;
   if (n > (1 << 24)) v += stb_fgetc(f) << 24;
   if (n > (1 << 16)) v += stb_fgetc(f) << 16;
   if (n > (1 <<  8)) v += stb_fgetc(f) <<  8;
   v += stb_fgetc(f);
   return b+v;
}

int     stb_size_ranged(int b, stb_uint n)
{
   if (n > (1 << 24)) return 4;
   if (n > (1 << 16)) return 3;
   if (n > (1 <<  8)) return 2;
   return 1;
}

void stb_fput_string(FILE *f, char *s)
{
   int len = strlen(s);
   stb_fput_varlenu(f, len);
   fwrite(s, 1, len, f);
}

// inverse of the above algorithm
char *stb_fget_string(FILE *f, void *p)
{
   char *s;
   int len = stb_fget_varlenu(f);
   if (len > 4096) return NULL;
   s = p ? stb_malloc_string(p, len+1) : (char *) malloc(len+1);
   fread(s, 1, len, f);
   s[len] = 0;
   return s;
}

char *stb_strdup(char *str, void *pool)
{
   int len = strlen(str);
   char *p = stb_malloc_string(pool, len+1);
   strcpy(p, str);
   return p;
}

// strip the trailing '/' or '\\' from a directory so we can refer to it
// as a file for _stat()
char *stb_strip_final_slash(char *t)
{
   if (t[0]) {
      char *z = t + strlen(t) - 1;
      // *z is the last character
      if (*z == '\\' || *z == '//')
         if (z != t+2 || t[1] != ':') // but don't strip it if it's e.g. "c:/"
            *z = 0;
      if (*z == '\\')
         *z = '/'; // canonicalize to make sure it matches db
   }
   return t;
}
#endif

//////////////////////////////////////////////////////////////////////////////
//
//                 Options parsing
//

STB_EXTERN char **stb_getopt_param(int *argc, char **argv, char *param);
STB_EXTERN char **stb_getopt(int *argc, char **argv);
STB_EXTERN void   stb_getopt_free(char **opts);

#ifdef STB_DEFINE

void   stb_getopt_free(char **opts)
{
   int i;
   STB__ARR(char *) o2 = opts;
   for (i=0; i < stb_arr_len(o2); ++i)
      free(o2[i]);
   stb_arr_free(o2);
}

char **stb_getopt(int *argc, char **argv)
{
   return stb_getopt_param(argc, argv, "");
}

char **stb_getopt_param(int *argc, char **argv, char *param)
{
   STB__ARR(char *) opts=NULL;
   int i,j=1;
   for (i=1; i < *argc; ++i) {
      if (argv[i][0] != '-') {
         argv[j++] = argv[i];
      } else {
         if (argv[i][1] == 0) { // plain - == don't parse further options
            ++i;
            while (i < *argc)
               argv[j++] = argv[i++];
            break;
         } else {
            int k;
            char *q = argv[i];  // traverse options list
            for (k=1; q[k]; ++k) {
               char *s;
               if (strchr(param, q[k])) {  // does it take a parameter?
                  char *t = &q[k+1], z = q[k];
                  int len=0;
                  if (*t == 0) {
                     if (i == *argc-1) { // takes a parameter, but none found
                        *argc = 0;
                        stb_getopt_free(opts);
                        return NULL;
                     }
                     t = argv[++i];
                  } else
                     k += strlen(t);
                  len = strlen(t);
                  s = (char *) malloc(len+2);
                  if (!s) return NULL;
                  s[0] = z;
                  strcpy(s+1, t);
               } else {
                  // no parameter
                  s = (char *) malloc(2);
                  if (!s) return NULL;
                  s[0] = q[k];
                  s[1] = 0;
               }
               stb_arr_push(opts, s);
            }
         }
      }
   }
   stb_arr_push(opts, NULL);
   *argc = j;
   return opts;
}
#endif


//////////////////////////////////////////////////////////////////////////////
//
//                 Portable directory reading
//

STB_EXTERN char **stb_readdir_files  (char *dir);
STB_EXTERN char **stb_readdir_files_mask(char *dir, char *wild);
STB_EXTERN char **stb_readdir_subdirs(char *dir);
STB_EXTERN void   stb_readdir_free   (char **files);
STB_EXTERN char **stb_readdir_recursive(char *dir, char *filespec);
STB_EXTERN void stb_delete_directory_recursive(char *dir);

#ifdef STB_DEFINE

#ifdef _MSC_VER
#include <io.h>
#else
#include <unistd.h>
#include <dirent.h>
#endif

void stb_readdir_free(char **files)
{
   STB__ARR(char *) f2 = files;
   int i;
   for (i=0; i < stb_arr_len(f2); ++i)
      free(f2[i]);
   stb_arr_free(f2);
}

STB_EXTERN int stb_wildmatchi(char *expr, char *candidate);
static double stb_readdir_size;
static char **readdir_raw(char *dir, int return_subdirs, char *mask)
{
   STB__ARR(char *) results = NULL;
   char buffer[512], with_slash[512];
   int n;

   #ifdef _MSC_VER
      stb__wchar *ws;
      struct _wfinddata_t data;
      const long none = -1;
      long z;
   #else
      const DIR *none = NULL;
      DIR *z;
   #endif

   strcpy(buffer,dir);
   stb_fixpath(buffer);
   n = strlen(buffer);

   if (n > 0 && (buffer[n-1] != '/')) {
      buffer[n++] = '/';
   }
   buffer[n] = 0;
   strcpy(with_slash, buffer);

   #ifdef _MSC_VER
      strcpy(buffer+n, "*.*");
      ws = stb__from_utf8(buffer);
      z = _wfindfirst(ws, &data);
   #else
      z = opendir(dir);
   #endif


   if (z != none) {
      int nonempty = TRUE;
      #ifndef _MSC_VER
      struct dirent *data = readdir(z);
      nonempty = (data != NULL);
      #endif

      if (nonempty) {

         do {
            int is_subdir;
            #ifdef _MSC_VER
            char *name = stb__to_utf8(data.name);
            if (name == NULL) {
               printf("Unable to convert '%S' to utf8!\n", data.name);
               continue;
            }
            is_subdir = !!(data.attrib & _A_SUBDIR);
            #else
            char *name = data->d_name;
            strcpy(buffer+n,name);
            DIR *y = opendir(buffer);
            is_subdir = (y != NULL);
            if (y != NULL) closedir(y);
            #endif
        
            if (is_subdir == return_subdirs) {
               if (!is_subdir || name[0] != '.') {
                  if (!mask || stb_wildmatchi(mask, name)) {
                     char buffer[512],*p=buffer;
                     sprintf(buffer, "%s%s", with_slash, name);
                     if (buffer[0] == '.' && buffer[1] == '/')
                        p = buffer+2;
                     stb_arr_push(results, strdup(p));
                     #ifdef _MSC_VER
                     if (!is_subdir)
                        stb_readdir_size += data.size;
                     #endif
                  }
               }
            }
         }
         #ifdef _MSC_VER
         while (0 == _wfindnext(z, &data));
         #else
         while ((data = readdir(z)) != NULL);
         #endif
      }
      #ifdef _MSC_VER
         _findclose(z);
      #else
         closedir(z);
      #endif
   }
   return results;
}

char **stb_readdir_files  (char *dir) { return readdir_raw(dir, 0, NULL); }
char **stb_readdir_subdirs(char *dir) { return readdir_raw(dir, 1, NULL); }
char **stb_readdir_files_mask(char *dir, char *wild) { return readdir_raw(dir, 0, wild); }

int stb__rec_max=0x7fffffff;
static char **stb_readdir_rec(STB__ARR(char *) sofar, char *dir, char *filespec)
{
   int n = strcmp(dir, ".") ? strlen(dir)+1 : 0;
   STB__ARR(char *) files;
   STB__ARR(char *) dirs;
   char **p;

   if (stb_arr_len(sofar) >= stb__rec_max) return sofar;

   files = stb_readdir_files_mask(dir, filespec);
   stb_arr_for(p, files) {
      stb_arr_push(sofar, strdup(*p));
      if (stb_arr_len(sofar) >= stb__rec_max) break;
   }
   stb_readdir_free(files);
   if (stb_arr_len(sofar) >= stb__rec_max) return sofar;

   dirs = stb_readdir_subdirs(dir);
   stb_arr_for(p, dirs)
      sofar = stb_readdir_rec(sofar, *p, filespec);
   stb_readdir_free(dirs);
   return sofar;
}

char **stb_readdir_recursive(char *dir, char *filespec)
{
   return stb_readdir_rec(NULL, dir, filespec);
}

void stb_delete_directory_recursive(char *dir)
{
   STB__ARR(char *) list = stb_readdir_subdirs(dir);
   int i;
   for (i=0; i < stb_arr_len(list); ++i)
      stb_delete_directory_recursive(list[i]);
   stb_arr_free(list);
   list = stb_readdir_files(dir);
   for (i=0; i < stb_arr_len(list); ++i)
      if (!remove(list[i])) {
         // on windows, try again after making it writeable; don't ALWAYS
         // do this first since that would be slow in the normal case
         #ifdef _MSC_VER
         _chmod(list[i], _S_IWRITE);
         remove(list[i]);
         #endif
      }
   stb_arr_free(list);
   stb__windows(_rmdir,rmdir)(dir);
}

#endif

//////////////////////////////////////////////////////////////////////////////
//
//   construct trees from filenames; useful for cmirror summaries

typedef struct stb_dirtree2 stb_dirtree2;

struct stb_dirtree2
{
   STB__ARR(stb_dirtree2 *) subdirs;

   // make convenient for stb_summarize_tree
   int num_subdir;
   float weight;

   // actual data
   char *fullpath;
   char *relpath;
   STB__ARR(char *) files;
};

STB_EXTERN stb_dirtree2 *stb_dirtree2_from_files_relative(char *src, char **filelist, int count);
STB_EXTERN stb_dirtree2 *stb_dirtree2_from_files(char **filelist, int count);
STB_EXTERN int stb_dir_is_prefix(char *dir, int dirlen, char *file);

#ifdef STB_DEFINE

int stb_dir_is_prefix(char *dir, int dirlen, char *file)
{
   if (dirlen == 0) return TRUE;
   if (stb_strnicmp(dir, file, dirlen)) return FALSE;
   if (file[dirlen] == '/' || file[dirlen] == '\\') return TRUE;
   return FALSE;
}

stb_dirtree2 *stb_dirtree2_from_files_relative(char *src, char **filelist, int count)
{
   char buffer1[1024];
   int i;
   int dlen = strlen(src), elen;
   stb_dirtree2 *d;
   STB__ARR(char *) descendents = NULL;
   STB__ARR(char *) files = NULL;
   char *s;
   if (!count) return NULL;
   // first find all the ones that belong here... note this is will take O(NM) with N files and M subdirs
   for (i=0; i < count; ++i) {
      if (stb_dir_is_prefix(src, dlen, filelist[i])) {
         stb_arr_push(descendents, filelist[i]);
      }
   }
   if (descendents == NULL)
      return NULL;
   elen = dlen;
   // skip a leading slash
   if (elen == 0 && (descendents[0][0] == '/' || descendents[0][0] == '\\'))
      ++elen;
   else if (elen)
      ++elen;
   // now extract all the ones that have their root here
   for (i=0; i < stb_arr_len(descendents);) {
      if (!stb_strchr2(descendents[i]+elen, '/', '\\')) {
         stb_arr_push(files, descendents[i]);
         descendents[i] = descendents[stb_arr_len(descendents)-1];
         stb_arr_pop(descendents);
      } else
         ++i;
   }
   // now create a record
   d = (stb_dirtree2 *) malloc(sizeof(*d));
   d->files = files;
   d->subdirs = NULL;
   d->fullpath = strdup(src);
   s = stb_strrchr2(d->fullpath, '/', '\\');
   if (s)
      ++s;
   else
      s = d->fullpath;
   d->relpath = s;
   // now create the children
   stb_cmpoffset(0);
   qsort(descendents, stb_arr_len(descendents), sizeof(char *), stb_qsort_stricmp);
   buffer1[0] = 0;
   for (i=0; i < stb_arr_len(descendents); ++i) {
      char buffer2[1024];
      char *s = descendents[i] + elen, *t;
      t = stb_strchr2(s, '/', '\\');
      assert(t);
      stb_strncpy(buffer2, descendents[i], t-descendents[i]+1);
      if (stb_stricmp(buffer1, buffer2)) {
         stb_dirtree2 *t = stb_dirtree2_from_files_relative(buffer2, descendents, stb_arr_len(descendents));
         assert(t != NULL);
         strcpy(buffer1, buffer2);
         stb_arr_push(d->subdirs, t);
      }
   }
   d->num_subdir = stb_arr_len(d->subdirs);
   d->weight = 0;
   return d;
}

stb_dirtree2 *stb_dirtree2_from_files(char **filelist, int count)
{
   return stb_dirtree2_from_files_relative("", filelist, count);
}
#endif

//////////////////////////////////////////////////////////////////////////////
//
//                 Checksums: CRC-32, ADLER32, SHA-1
//
//    CRC-32 and ADLER32 allow streaming blocks
//    SHA-1 requires either a complete buffer, max size 2^32 - 73
//          or it can checksum directly from a file, max 2^61

#define STB_ADLER32_SEED   1
#define STB_CRC32_SEED     0    // note that we logical NOT this in the code

STB_EXTERN stb_uint 
  stb_adler32(stb_uint adler32, stb_uchar *buffer, stb_uint buflen);
STB_EXTERN stb_uint 
  stb_crc32_block(stb_uint crc32, stb_uchar *buffer, stb_uint len);
STB_EXTERN stb_uint stb_crc32(unsigned char *buffer, stb_uint len);

STB_EXTERN void stb_sha1(
  unsigned char output[20], unsigned char *buffer, unsigned int len);
STB_EXTERN int stb_sha1_file(unsigned char output[20], char *file);

STB_EXTERN void stb_sha1_readable(char display[27], unsigned char sha[20]);

#ifdef STB_DEFINE
stb_uint stb_crc32_block(stb_uint crc, unsigned char *buffer, stb_uint len)
{
   static stb_uint crc_table[256];
   stb_uint i,j,s;
   crc = ~crc;

   if (crc_table[1] == 0)
      for(i=0; i < 256; i++) {
         for (s=i, j=0; j < 8; ++j)
            s = (s >> 1) ^ (s & 1 ? 0xedb88320 : 0);
         crc_table[i] = s;
      }
   for (i=0; i < len; ++i)
      crc = (crc >> 8) ^ crc_table[buffer[i] ^ (crc & 0xff)];
   return ~crc;
}

stb_uint stb_crc32(unsigned char *buffer, stb_uint len)
{
   return stb_crc32_block(0, buffer, len);
}

stb_uint stb_adler32(stb_uint adler32, stb_uchar *buffer, stb_uint buflen)
{
   const unsigned long ADLER_MOD = 65521;
   unsigned long s1 = adler32 & 0xffff, s2 = adler32 >> 16;
   unsigned long blocklen, i;

   blocklen = buflen % 5552;
   while (buflen) {
      for (i=0; i + 7 < blocklen; i += 8) {
         s1 += buffer[0], s2 += s1;
         s1 += buffer[1], s2 += s1;
         s1 += buffer[2], s2 += s1;
         s1 += buffer[3], s2 += s1;
         s1 += buffer[4], s2 += s1;
         s1 += buffer[5], s2 += s1;
         s1 += buffer[6], s2 += s1;
         s1 += buffer[7], s2 += s1;

         buffer += 8;
      }

      for (; i < blocklen; ++i)
         s1 += *buffer++, s2 += s1;

      s1 %= ADLER_MOD, s2 %= ADLER_MOD;
      buflen -= blocklen;
      blocklen = 5552;
   }
   return (s2 << 16) + s1;
}

static void stb__sha1(stb_uchar *chunk, stb_uint h[5])
{
   int i;
   stb_uint a,b,c,d,e;
   stb_uint w[80];

   for (i=0; i < 16; ++i)
      w[i] = stb_big32(&chunk[i*4]);
   for (i=16; i < 80; ++i) {
      stb_uint t;
      t = w[i-3] ^ w[i-8] ^ w[i-14] ^ w[i-16];
      w[i] = (t + t) | (t >> 31);
   }

   a = h[0];
   b = h[1];
   c = h[2];
   d = h[3];
   e = h[4];

   #define STB__SHA1(k,f)                                            \
   {                                                                 \
      stb_uint temp = (a << 5) + (a >> 27) + (f) + e + (k) + w[i];  \
      e = d;                                                       \
      d = c;                                                     \
      c = (b << 30) + (b >> 2);                               \
      b = a;                                              \
      a = temp;                                    \
   }

   i=0;
   for (; i < 20; ++i) STB__SHA1(0x5a827999, d ^ (b & (c ^ d))       );
   for (; i < 40; ++i) STB__SHA1(0x6ed9eba1, b ^ c ^ d               );
   for (; i < 60; ++i) STB__SHA1(0x8f1bbcdc, (b & c) + (d & (b ^ c)) );
   for (; i < 80; ++i) STB__SHA1(0xca62c1d6, b ^ c ^ d               );

   #undef STB__SHA1

   h[0] += a;
   h[1] += b;
   h[2] += c;
   h[3] += d;
   h[4] += e;
}

void stb_sha1(stb_uchar output[20], stb_uchar *buffer, stb_uint len)
{
   unsigned char final_block[128];
   stb_uint end_start, final_len, j;
   int i;

   stb_uint h[5];

   h[0] = 0x67452301;
   h[1] = 0xefcdab89;
   h[2] = 0x98badcfe;
   h[3] = 0x10325476;
   h[4] = 0xc3d2e1f0;

   // we need to write padding to the last one or two
   // blocks, so build those first into 'final_block'

   // we have to write one special byte, plus the 8-byte length

   // compute the block where the data runs out
   end_start = len & ~63;

   // compute the earliest we can encode the length
   if (((len+9) & ~63) == end_start) {
      // it all fits in one block, so fill a second-to-last block
      end_start -= 64;
   }

   final_len = end_start + 128;

   // now we need to copy the data in
   assert(end_start + 128 >= len+9);
   assert(end_start < len || len < 64-9);

   j = 0;
   if (end_start > len)
      j = (stb_uint) - (int) end_start;

   for (; end_start + j < len; ++j)
      final_block[j] = buffer[end_start + j];
   final_block[j++] = 0x80;
   while (j < 128-5) // 5 byte length, so write 4 extra padding bytes
      final_block[j++] = 0;
   // big-endian size
   final_block[j++] = len >> 29;
   final_block[j++] = len >> 21;
   final_block[j++] = len >> 13;
   final_block[j++] = len >>  5;
   final_block[j++] = len <<  3;
   assert(j == 128 && end_start + j == final_len);

   for (j=0; j < final_len; j += 64) { // 512-bit chunks
      if (j+64 >= end_start+64)
         stb__sha1(&final_block[j - end_start], h);
      else
         stb__sha1(&buffer[j], h);
   }

   for (i=0; i < 5; ++i) {
      output[i*4 + 0] = h[i] >> 24;
      output[i*4 + 1] = h[i] >> 16;
      output[i*4 + 2] = h[i] >>  8;
      output[i*4 + 3] = h[i] >>  0;
   }
}

#ifdef _MSC_VER
// @TODO: rewrite this to not use 64-bit numbers, e.g.
// manually use 2 32-bit ints (or get stb__64 ported)
int stb_sha1_file(stb_uchar output[20], char *file)
{
   int i;
   stb__64 length=0;
   unsigned char buffer[128];

   FILE *f = stb__fopen(file, "rb");
   stb_uint h[5];

   if (f == NULL) return 0; // file not found

   h[0] = 0x67452301;
   h[1] = 0xefcdab89;
   h[2] = 0x98badcfe;
   h[3] = 0x10325476;
   h[4] = 0xc3d2e1f0;

   for(;;) {
      int n = fread(buffer, 1, 64, f);
      if (n == 64) {
         stb__sha1(buffer, h);
         length += n;
      } else {
         int block = 64;

         length += n;

         buffer[n++] = 0x80;

         // if there isn't enough room for the length, double the block
         if (n + 8 > 64) 
            block = 128;

         // pad to end
         memset(buffer+n, 0, block-8-n);

         i = block - 8;
         buffer[i++] = (stb_uchar) (length >> 53);
         buffer[i++] = (stb_uchar) (length >> 45);
         buffer[i++] = (stb_uchar) (length >> 37);
         buffer[i++] = (stb_uchar) (length >> 29);
         buffer[i++] = (stb_uchar) (length >> 21);
         buffer[i++] = (stb_uchar) (length >> 13);
         buffer[i++] = (stb_uchar) (length >>  5);
         buffer[i++] = (stb_uchar) (length <<  3);
         assert(i == block);
         stb__sha1(buffer, h);
         if (block == 128)
            stb__sha1(buffer+64, h);
         else
            assert(block == 64);
         break;
      }
   }
   fclose(f);

   for (i=0; i < 5; ++i) {
      output[i*4 + 0] = h[i] >> 24;
      output[i*4 + 1] = h[i] >> 16;
      output[i*4 + 2] = h[i] >>  8;
      output[i*4 + 3] = h[i] >>  0;
   }

   return 1;
}
#endif // _MSC_VER

// client can truncate this wherever they like
void stb_sha1_readable(char display[27], unsigned char sha[20])
{
   char encoding[65] = "0123456789abcdefghijklmnopqrstuv"
                       "wxyzABCDEFGHIJKLMNOPQRSTUVWXYZ%$";
   int num_bits = 0, acc=0;
   int i=0,o=0;
   while (o < 26) {
      int v;
      // expand the accumulator
      if (num_bits < 6) {
         assert(i != 20);
         acc += sha[i++] << num_bits;
         num_bits += 8;
      }
      v = acc & ((1 << 6) - 1);
      display[o++] = encoding[v];
      acc >>= 6;
      num_bits -= 6;
   }
   assert(num_bits == 20*8 - 26*6);
   display[o++] = encoding[acc];   
}

#endif // STB_DEFINE

///////////////////////////////////////////////////////////
//
// simplified WINDOWS registry interface... hopefully
// we'll never actually use this?

#ifdef _WIN32
STB_EXTERN void * stb_reg_open(char *mode, char *where); // mode: "rHKLM" or "rHKCU" or "w.."
STB_EXTERN void   stb_reg_close(void *reg);
STB_EXTERN int    stb_reg_read(void *zreg, char *str, void *data, int len);
STB_EXTERN int    stb_reg_read_string(void *zreg, char *str, char *data, int len);
STB_EXTERN void   stb_reg_write(void *zreg, char *str, void *data, int len);
STB_EXTERN void   stb_reg_write_string(void *zreg, char *str, char *data);

#ifdef STB_DEFINE
#ifndef _WINDOWS_

#define HKEY void *

STB_EXTERN __declspec(dllimport) long __stdcall RegCloseKey ( HKEY hKey );
STB_EXTERN __declspec(dllimport) long __stdcall RegCreateKeyExA ( HKEY hKey, const char * lpSubKey,
    int  Reserved, char * lpClass, int  dwOptions, 
    int samDesired, void *lpSecurityAttributes,     HKEY * phkResult,     int * lpdwDisposition );
STB_EXTERN __declspec(dllimport) long __stdcall RegDeleteKeyA ( HKEY hKey, const char * lpSubKey );
STB_EXTERN __declspec(dllimport) long __stdcall RegQueryValueExA ( HKEY hKey, const char * lpValueName,
    int * lpReserved, int * lpType, unsigned char * lpData, int * lpcbData );
STB_EXTERN __declspec(dllimport) long __stdcall RegSetValueExA ( HKEY hKey, const char * lpValueName,
    int  Reserved, int  dwType, const unsigned char* lpData, int  cbData );
STB_EXTERN __declspec(dllimport) long __stdcall  RegOpenKeyExA ( HKEY hKey, const char * lpSubKey,
    int ulOptions, int samDesired, HKEY * phkResult );

#endif // _WINDOWS_

#define STB__REG_OPTION_NON_VOLATILE  0
#define STB__REG_KEY_ALL_ACCESS       0x000f003f
#define STB__REG_KEY_READ             0x00020019

void *stb_reg_open(char *mode, char *where)
{
   long res;
   HKEY base;
   HKEY zreg;
   if (!stricmp(mode+1, "cu") || !stricmp(mode+1, "hkcu"))
      base = (HKEY) 0x80000001; // HKCU
   else if (!stricmp(mode+1, "lm") || !stricmp(mode+1, "hklm"))
      base = (HKEY) 0x80000002; // HKLM
   else
      return NULL;

   if (mode[0] == 'r')
      res = RegOpenKeyExA(base, where, 0, STB__REG_KEY_READ, &zreg);
   else if (mode[0] == 'w')
      res = RegCreateKeyExA(base, where,  0, NULL, STB__REG_OPTION_NON_VOLATILE, STB__REG_KEY_ALL_ACCESS, NULL, &zreg, NULL);
   else
      return NULL;

   return res ? NULL : zreg;
}

void stb_reg_close(void *reg)
{
   RegCloseKey((HKEY) reg);
}

#define STB__REG_SZ         1
#define STB__REG_BINARY     3
#define STB__REG_DWORD      4

int stb_reg_read(void *zreg, char *str, void *data, int len)
{
   int type;
   int alen = len;
   if (0 == RegQueryValueExA((HKEY) zreg, str, 0, &type, (unsigned char *) data, &len))
      if (type == STB__REG_BINARY || type == STB__REG_SZ || type == STB__REG_DWORD) {
         if (len < alen)
            *((char *) data + len) = 0;
         return 1;
      }
   return 0;
}

void stb_reg_write(void *zreg, char *str, void *data, int len)
{
   if (zreg)
      RegSetValueExA((HKEY) zreg, str, 0, STB__REG_BINARY, (const unsigned char *) data, len);
}

int stb_reg_read_string(void *zreg, char *str, char *data, int len)
{
   if (!stb_reg_read(zreg, str, data, len)) return 0;
   data[len-1] = 0; // force a 0 at the end of the string no matter what
   return 1;
}

void stb_reg_write_string(void *zreg, char *str, char *data)
{
   if (zreg)
      RegSetValueExA((HKEY) zreg, str, 0, STB__REG_SZ, (const unsigned char *)  data, strlen(data)+1);
}
#endif  // STB_DEFINE
#endif  // _WIN32


//////////////////////////////////////////////////////////////////////////////
//
//     stb_cfg - This is like the registry, but the config info
//               is all stored in plain old files where we can
//               backup and restore them easily. The LOCATION of
//               the config files is gotten from... the registry!

#ifndef STB_NO_STB_STRINGS
typedef struct stb_cfg_st stb_cfg;

STB_EXTERN stb_cfg * stb_cfg_open(char *config, char *mode); // mode = "r", "w"
STB_EXTERN void      stb_cfg_close(stb_cfg *cfg);
STB_EXTERN int       stb_cfg_read(stb_cfg *cfg, char *key, void *value, int len);
STB_EXTERN void      stb_cfg_write(stb_cfg *cfg, char *key, void *value, int len);
STB_EXTERN int       stb_cfg_read_string(stb_cfg *cfg, char *key, char *value, int len);
STB_EXTERN void      stb_cfg_write_string(stb_cfg *cfg, char *key, char *value);
STB_EXTERN int       stb_cfg_delete(stb_cfg *cfg, char *key);

#ifdef STB_DEFINE

typedef struct
{
   char *key;
   void *value;
   int value_len;
} stb__cfg_item;

struct stb_cfg_st
{
   STB__ARR(stb__cfg_item) data;
   char *loaded_file;   // this needs to be freed
   FILE *f; // write the data to this file on close
};

static char *stb__cfg_sig = "sTbCoNfIg!\0\0";

STB_EXTERN stb_cfg * stb_cfg_open(char *config, char *mode)
{
   unsigned int len;
   stb_cfg *z;
   char file[512];
   void *reg;
   if (mode[0] != 'r' && mode[0] != 'w') return NULL;

   reg = stb_reg_open("rHKLM", "Software\\SilverSpaceship\\stb");
   strcpy(file, "c:/stb");
   if (reg) {
      stb_reg_read_string(reg, "config_dir", file, sizeof(file));
      stb_reg_close(reg);
   }

   strcat(file, "/");
   strcat(file, config);
   strcat(file, ".cfg");

   z = (stb_cfg *) stb_malloc(0, sizeof(*z));
   z->data = NULL;

   z->loaded_file = stb_filec(file, &len);
   if (z->loaded_file) {
      char *s = z->loaded_file;
      if (!memcmp(s, stb__cfg_sig, 12)) {
         char *s = z->loaded_file + 12;
         while (s < z->loaded_file + len) {
            stb__cfg_item a;
            int n = *(int16 *) s;
            a.key = s+2;
            s = s+2 + n;
            a.value_len = *(int *) s;
            s += 4;
            a.value = s;
            s += a.value_len;
            stb_arr_push(z->data, a);
         }
         assert(s == z->loaded_file + len);
      }
   }

   if (mode[0] == 'w')
      z->f = fopen(file, "wb");
   else
      z->f = NULL;

   return z;
}

void stb_cfg_close(stb_cfg *z)
{
   if (z->f) {
      int i;
      // write the file out
      fwrite(stb__cfg_sig, 12, 1, z->f);
      for (i=0; i < stb_arr_len(z->data); ++i) {
         int16 n = strlen(z->data[i].key)+1;
         fwrite(&n, 2, 1, z->f);
         fwrite(z->data[i].key, n, 1, z->f);
         fwrite(&z->data[i].value_len, 4, 1, z->f);
         fwrite(z->data[i].value, z->data[i].value_len, 1, z->f);
      }
      fclose(z->f);
   }
   stb_arr_free(z->data);
   stb_free(z);
}

int stb_cfg_read(stb_cfg *z, char *key, void *value, int len)
{
   int i;
   for (i=0; i < stb_arr_len(z->data); ++i) {
      if (!stricmp(z->data[i].key, key)) {
         int n = stb_min(len, z->data[i].value_len);
         memcpy(value, z->data[i].value, n);
         if (n < len)
            *((char *) value + n) = 0;
         return 1;
      }
   }
   return 0;
}

void stb_cfg_write(stb_cfg *z, char *key, void *value, int len)
{
   int i;
   for (i=0; i < stb_arr_len(z->data); ++i)
      if (!stricmp(z->data[i].key, key))
         break;
   if (i == stb_arr_len(z->data)) {
      stb__cfg_item p;
      p.key = stb_strdup(key, z);
      p.value = NULL;
      p.value_len = 0;
      stb_arr_push(z->data, p);
   }
   z->data[i].value = stb_malloc(z, len);
   z->data[i].value_len = len;
   memcpy(z->data[i].value, value, len);
}

int stb_cfg_delete(stb_cfg *z, char *key)
{
   int i;
   for (i=0; i < stb_arr_len(z->data); ++i)
      if (!stricmp(z->data[i].key, key)) {   
         stb_arr_fastdelete(z->data, i);
         return 1;
      }
   return 0;
}

int stb_cfg_read_string(stb_cfg *z, char *key, char *value, int len)
{
   if (!stb_cfg_read(z, key, value, len)) return 0;
   value[len-1] = 0;
   return 1;
}

void stb_cfg_write_string(stb_cfg *z, char *key, char *value)
{
   stb_cfg_write(z, key, value, strlen(value)+1);
}
#endif

//////////////////////////////////////////////////////////////////////////////
//
//     stb_dirtree  - load a description of a directory tree
//                      uses a cache and stat()s the directories for changes
//                      MUCH faster on NTFS, _wrong_ on FAT32, so should
//                      ignore the db on FAT32

#ifdef _WIN32

typedef struct
{
   char   * path;           // full path from passed-in root
   time_t   last_modified;
   int      num_files;
} stb_dirtree_dir;

typedef struct
{
   char *name;              // name relative to path
   int   dir;               // index into dirs[] array
   unsigned long size;      // size, max 4GB
   time_t   last_modified;
} stb_dirtree_file;

typedef struct
{
   STB__ARR(stb_dirtree_dir)  dirs;
   STB__ARR(stb_dirtree_file) files;

   // internal use
   void             * string_pool;   // used to free data en masse
} stb_dirtree;

extern void         stb_dirtree_free          ( stb_dirtree *d );
extern stb_dirtree *stb_dirtree_get           ( char *dir);
extern stb_dirtree *stb_dirtree_get_dir       ( char *dir, char *cache_dir);
extern stb_dirtree *stb_dirtree_get_with_file ( char *dir, char *cache_file);

// get a list of all the files recursively underneath 'dir'
//
// cache_file is used to store a copy of the directory tree to speed up
// later calls. It must be unique to 'dir' and the current working
// directory! Otherwise who knows what will happen (a good solution
// is to put it _in_ dir, but this API doesn't force that).
//
// Also, it might be possible to break this if you have two different processes
// do a call to stb_dirtree_get() with the same cache file at about the same
// time, but I _think_ it might just work.


#ifdef STB_DEFINE
static void stb__dirtree_add_dir(char *path, time_t last, stb_dirtree *active)
{
   stb_dirtree_dir d;
   d.last_modified = last;
   d.num_files = 0;
   d.path = stb_strdup(path, active->string_pool);
   stb_arr_push(active->dirs, d);
}

static void stb__dirtree_add_file(char *name, int dir, unsigned long size, time_t last, stb_dirtree *active)
{
   stb_dirtree_file f;
   f.dir = dir;
   f.size = size;
   f.last_modified = last;
   f.name = stb_strdup(name, active->string_pool);
   ++active->dirs[dir].num_files;
   stb_arr_push(active->files, f);
}

static char stb__signature[12] = { 's', 'T', 'b', 'D', 'i', 'R', 't', 'R', 'e', 'E', '0', '1' };

static void stb__dirtree_save_db(char *filename, stb_dirtree *data, char *root)
{
   int i, num_dirs_final=0, num_files_final;
   int *remap;
   FILE *f = fopen(filename, "wb");
   if (!f) return;

   fwrite(stb__signature, sizeof(stb__signature), 1, f);
   fwrite(root, strlen(root)+1, 1, f);
   // need to be slightly tricky and not write out NULLed directories, nor the root

   // build remapping table of all dirs we'll be writing out
   remap = (int *) malloc(sizeof(remap[0]) * stb_arr_len(data->dirs));
   for (i=0; i < stb_arr_len(data->dirs); ++i) {
      if (data->dirs[i].path == NULL || 0==stricmp(data->dirs[i].path, root)) {
         remap[i] = -1;
      } else {
         remap[i] = num_dirs_final++;
      }
   }

   fwrite(&num_dirs_final, 4, 1, f);
   for (i=0; i < stb_arr_len(data->dirs); ++i) {
      if (remap[i] >= 0) {
         fwrite(&data->dirs[i].last_modified, 4, 1, f);
         stb_fput_string(f, data->dirs[i].path);
      }
   }

   num_files_final = 0;
   for (i=0; i < stb_arr_len(data->files); ++i)
      if (remap[data->files[i].dir] >= 0)
         ++num_files_final;

   fwrite(&num_files_final, 4, 1, f);
   for (i=0; i < stb_arr_len(data->files); ++i) {
      if (remap[data->files[i].dir] >= 0) {
         stb_fput_ranged(f, remap[data->files[i].dir], 0, num_dirs_final);
         stb_fput_varlenu(f, data->files[i].size);
         fwrite(&data->files[i].last_modified, 4, 1, f);
         stb_fput_string(f, data->files[i].name);
      }
   }

   fclose(f);
}

// note: stomps any existing data, rather than appending
static void stb__dirtree_load_db(char *filename, stb_dirtree *data, char *dir)
{
   char sig[2048];
   int i,n;
   FILE *f = fopen(filename, "rb");

   if (!f) return;

   data->string_pool = stb_malloc(0,1);

   fread(sig, sizeof(stb__signature), 1, f);
   if (memcmp(stb__signature, sig, sizeof(stb__signature))) { fclose(f); return; }
   if (!fread(sig, strlen(dir)+1, 1, f))                    { fclose(f); return; }
   if (stricmp(sig,dir))                                    { fclose(f); return; }

   // we can just read them straight in, because they're guaranteed to be valid
   fread(&n, 4, 1, f);
   stb_arr_setlen(data->dirs, n);
   for(i=0; i < stb_arr_len(data->dirs); ++i) {
      fread(&data->dirs[i].last_modified, 4, 1, f);
      data->dirs[i].path = stb_fget_string(f, data->string_pool);
      if (data->dirs[i].path == NULL) goto bail;
   }
   fread(&n, 4, 1, f);
   stb_arr_setlen(data->files, n);
   for (i=0; i < stb_arr_len(data->files); ++i) {
      data->files[i].dir  = stb_fget_ranged(f, 0, stb_arr_len(data->dirs));
      data->files[i].size = stb_fget_varlenu(f);
      fread(&data->files[i].last_modified, 4, 1, f);
      data->files[i].name = stb_fget_string(f, data->string_pool);
      if (data->files[i].name == NULL) goto bail;
   }

   if (0) {
      bail:
         data->dirs = stb_arr_free(data->dirs);
         data->files = stb_arr_free(data->files);
   }
   fclose(f);
}

static void stb__dirtree_scandir(char *path, time_t last_time, stb_dirtree *active)
{
   // this is dumb depth first; theoretically it might be faster
   // to fully traverse each directory before visiting its children,
   // but it's complicated and didn't seem like a gain in the test app

   int n;

   struct _wfinddata_t c_file;
   long hFile;
   stb__wchar full_path[1024];
   if (path[0] && path[strlen(path)-1] == '/')
      swprintf(full_path, L"%s*", stb__from_utf8(path));
   else
      swprintf(full_path, L"%s/*", stb__from_utf8(path));

   // it's possible this directory is already present: that means it was in the
   // cache, but its parent wasn't... in that case, we're done with it
   for (n=0; n < stb_arr_len(active->dirs); ++n)
      if (0 == stricmp(active->dirs[n].path, path))
         return;

   // otherwise, we need to add it
   stb__dirtree_add_dir(path, last_time, active);
   n = stb_arr_lastn(active->dirs);

   if( (hFile = _wfindfirst( full_path, &c_file )) != -1L ) {
      do {
         if (c_file.attrib & _A_SUBDIR) {
            // ignore subdirectories starting with '.', e.g. "." and ".."
            if (c_file.name[0] != '.') {
               char *new_path = (char *) full_path;
               char *temp = stb__to_utf8(c_file.name);
               sprintf(new_path, "%s/%s", path, temp);
               stb__dirtree_scandir(new_path, c_file.time_write, active);
            }
         } else {
            char *temp = stb__to_utf8(c_file.name);
            stb__dirtree_add_file(temp, n, c_file.size, c_file.time_write, active);
         }
      } while( _wfindnext( hFile, &c_file ) == 0 );

      _findclose( hFile );
   }
}

// scan the database and see if it's all valid
static int stb__dirtree_update_db(stb_dirtree *db, stb_dirtree *active)
{
   int changes_detected = FALSE;
   int i;
   int *remap;
   STB__ARR(int) rescan=NULL;
   remap = (int *) malloc(sizeof(remap[0]) * stb_arr_len(db->dirs));
   memset(remap, 0, sizeof(remap[0]) * stb_arr_len(db->dirs));
   rescan = NULL;

   for (i=0; i < stb_arr_len(db->dirs); ++i) {
      struct _stat info;
      if (0 == _stat(db->dirs[i].path, &info)) {
         if (info.st_mode & _S_IFDIR) {
            // it's still a directory, as expected
            if (info.st_mtime > db->dirs[i].last_modified) {
               // it's changed! force a rescan
               // we don't want to scan it until we've stat()d its
               // subdirs, though, so we queue it
               stb_arr_push(rescan, i);
               // update the last_mod time
               db->dirs[i].last_modified = info.st_mtime;
               // ignore existing files in this dir
               remap[i] = -1;
               changes_detected = TRUE;
            } else {
               // it hasn't changed, just copy it through unchanged
               stb__dirtree_add_dir(db->dirs[i].path, db->dirs[i].last_modified, active);
               remap[i] = stb_arr_lastn(active->dirs);
            }
         } else {
            // this path used to refer to a directory, but now it's a file!
            // assume that the parent directory is going to be forced to rescan anyway
            goto delete_entry;
         }
      } else {
        delete_entry:
         // directory no longer exists, so don't copy it
         // we don't free it because it's in the string pool now
         db->dirs[i].path = NULL;
         remap[i] = -1;
         changes_detected = TRUE;
      }
   }

   // at this point, we have:
   //
   //   <rescan> holds a list of directory indices that need to be scanned due to being out of date
   //   <remap> holds the directory index in <active> for each dir in <db>, if it exists; -1 if not
   //           directories in <rescan> are not in <active> yet

   // so we can go ahead and remap all the known files right now
   for (i=0; i < stb_arr_len(db->files); ++i) {
      int dir = db->files[i].dir;
      if (remap[dir] >= 0) {
         stb__dirtree_add_file(db->files[i].name, remap[dir], db->files[i].size, db->files[i].last_modified, active);
      }
   }

   // at this point we're done with db->files, and done with remap
   free(remap);

   // now scan those directories using the standard scan
   for (i=0; i < stb_arr_len(rescan); ++i) {
      int z = rescan[i];
      stb__dirtree_scandir(db->dirs[z].path, db->dirs[z].last_modified, active);
   }
   stb_arr_free(rescan);

   return changes_detected;
}

static void stb__dirtree_free_raw(stb_dirtree *d)
{
   stb_free(d->string_pool);
   stb_arr_free(d->dirs);
   stb_arr_free(d->files);
}

stb_dirtree *stb_dirtree_get_with_file(char *dir, char *cache_file)
{
   stb_dirtree *output = (stb_dirtree *) malloc(sizeof(*output));
   stb_dirtree db,active;
   int prev_dir_count, cache_mismatch;

   char *stripped_dir; // store the directory name without a trailing '/' or '\\'

   // load the database of last-known state on disk
   db.string_pool = NULL;
   db.files = NULL;
   db.dirs = NULL;

   stripped_dir = stb_strip_final_slash(strdup(dir));

   if (cache_file != NULL)
      stb__dirtree_load_db(cache_file, &db, stripped_dir);

   active.files = NULL;
   active.dirs = NULL;
   active.string_pool = stb_malloc(0,1); // @TODO: share string pools between both?

   // check all the directories in the database; make note if
   // anything we scanned had changed, and rescan those things
   cache_mismatch = stb__dirtree_update_db(&db, &active);

   // check the root tree
   prev_dir_count = stb_arr_len(active.dirs);  // record how many directories we've seen

   stb__dirtree_scandir(stripped_dir, 0, &active);  // no last_modified time available for root

   // done with the DB; write it back out if any changes, i.e. either
   //      1. any inconsistency found between cached information and actual disk
   //   or 2. if scanning the root found any new directories--which we detect because
   //         more than one directory got added to the active db during that scan
   if (cache_mismatch || stb_arr_len(active.dirs) > prev_dir_count+1)
      stb__dirtree_save_db(cache_file, &active, stripped_dir);

   free(stripped_dir);

   stb__dirtree_free_raw(&db);

   *output = active;
   return output;
}

stb_dirtree *stb_dirtree_get_dir(char *dir, char *cache_dir)
{
   int i;
   uint8 sha[20];
   char dir_lower[1024];
   char cache_file[1024],*s;
   if (cache_dir == NULL)
      return stb_dirtree_get_with_file(dir, NULL);
   strcpy(dir_lower, dir);
   stb_tolower(dir_lower);
   stb_sha1(sha, (unsigned char *) dir_lower, strlen(dir_lower));
   strcpy(cache_file, cache_dir);
   s = cache_file + strlen(cache_file);
   if (s[-1] != '//' && s[-1] != '\\') *s++ = '/';
   strcpy(s, "dirtree_");
   s += strlen(s);
   for (i=0; i < 8; ++i) {
      char *hex = "0123456789abcdef";
      uint z = sha[i];
      *s++ = hex[z >> 4];
      *s++ = hex[z & 15];
   }
   strcpy(s, ".bin");
   return stb_dirtree_get_with_file(dir, cache_file);
}

stb_dirtree *stb_dirtree_get(char *dir)
{
   char cache_dir[256];
   void *reg = stb_reg_open("rHKLM", "Software\\SilverSpaceship\\stb");
   strcpy(cache_dir, "c:/stb");
   if (reg) {
      stb_reg_read(reg, "dirtree", cache_dir, sizeof(cache_dir));
      stb_reg_close(reg);
   }
   return stb_dirtree_get_dir(dir, cache_dir);
}

void stb_dirtree_free(stb_dirtree *d)
{
   stb__dirtree_free_raw(d);
   free(d);
}
#endif // STB_DEFINE

#endif // _WIN32
#endif // STB_NO_STB_STRINGS

//////////////////////////////////////////////////////////////////////////////
//
//  STB_MALLOC_WRAPPER
//
//    you can use the wrapper functions with your own malloc wrapper,
//    or define STB_MALLOC_WRAPPER project-wide to have
//    malloc/free/realloc/strdup all get vectored to it

#ifdef STB_DEFINE

typedef struct
{
   void *p;
   char *file;
   int  line;
   int  size;
} stb_malloc_record;

#ifndef STB_MALLOC_HISTORY_COUNT
#define STB_MALLOC_HISTORY_COUNT 50 // 800 bytes
#endif

stb_malloc_record *stb__allocations;
static int stb__alloc_size, stb__alloc_limit, stb__alloc_mask;
int stb__alloc_count;

stb_malloc_record stb__alloc_history[STB_MALLOC_HISTORY_COUNT];
int stb__history_pos;

static int stb__hashfind(void *p)
{
   uint32 h = stb_hashptr(p);
   int s,n = h & stb__alloc_mask;
   if (stb__allocations[n].p == p)
      return n;
   s = stb_rehash(h)|1;
   for(;;) {
      if (stb__allocations[n].p == NULL)
         return -1;
      n = (n+s) & stb__alloc_mask;
      if (stb__allocations[n].p == p)
         return n;
   }
}

int stb_wrapper_allocsize(void *p)
{
   int n = stb__hashfind(p);
   if (n < 0) return 0;
   return stb__allocations[n].size;
}

static int stb__historyfind(void *p)
{
   int n = stb__history_pos;
   int i;
   for (i=0; i < STB_MALLOC_HISTORY_COUNT; ++i) {
      if (--n < 0) n = STB_MALLOC_HISTORY_COUNT-1;
      if (stb__alloc_history[n].p == p)
         return n;
   }
   return -1;
}

static void stb__add_alloc(void *p, int sz, char *file, int line);
static void stb__grow_alloc(void)
{
   int i,old_num = stb__alloc_size;
   stb_malloc_record *old = stb__allocations;
   if (stb__alloc_size == 0)
      stb__alloc_size = 64;
   else
      stb__alloc_size *= 2;

   stb__allocations = (stb_malloc_record *) stb__realloc_raw(NULL, stb__alloc_size * sizeof(stb__allocations[0]));
   if (stb__allocations == NULL)
      stb_fatal("Internal error: couldn't grow malloc wrapper table");
   memset(stb__allocations, 0, stb__alloc_size * sizeof(stb__allocations[0]));
   stb__alloc_limit = (stb__alloc_size*3)>>2;
   stb__alloc_mask = stb__alloc_size-1;

   stb__alloc_count = 0;

   for (i=0; i < old_num; ++i)
      if (old[i].p > STB_DEL) {
         stb__add_alloc(old[i].p, old[i].size, old[i].file, old[i].line);
         assert(stb__hashfind(old[i].p) >= 0);
      }
   for (i=0; i < old_num; ++i)
      if (old[i].p > STB_DEL)
         assert(stb__hashfind(old[i].p) >= 0);
   stb__realloc_raw(old, 0);
}

static void stb__add_alloc(void *p, int sz, char *file, int line)
{
   uint32 h;
   int n, f=-1;
   if (stb__alloc_count >= stb__alloc_limit)
      stb__grow_alloc();
   h = stb_hashptr(p);
   n = h & stb__alloc_mask;
   if (stb__allocations[n].p > STB_DEL) {
      int s = stb_rehash(h)|1;
      do {
         n = (n+s) & stb__alloc_mask;
      } while (stb__allocations[n].p > STB_DEL);
   }
   assert(stb__allocations[n].p == NULL || stb__allocations[n].p == STB_DEL);
   stb__allocations[n].p = p;
   stb__allocations[n].size = sz;
   stb__allocations[n].line = line;
   stb__allocations[n].file = file;
   ++stb__alloc_count;
}

static void stb__remove_alloc(int n, char *file, int line)
{
   stb__alloc_history[stb__history_pos] = stb__allocations[n];
   stb__alloc_history[stb__history_pos].file = file;
   stb__alloc_history[stb__history_pos].line = line;
   if (++stb__history_pos == STB_MALLOC_HISTORY_COUNT)
      stb__history_pos = 0;
   stb__allocations[n].p = STB_DEL;
   --stb__alloc_count;
}

void stb_wrapper_malloc(void *p, int sz, char *file, int line)
{
   if (!p) return;
   stb__add_alloc(p,sz,file,line);
}

void stb_wrapper_free(void *p, char *file, int line)
{
   int n;
   
   if (p == NULL) return;

   n = stb__hashfind(p);

   if (n >= 0)
      stb__remove_alloc(n, file, line);
   else {
      // tried to free something we hadn't allocated!
      n = stb__historyfind(p);
      assert(0); /* NOTREACHED */
      if (n >= 0)
         stb_fatal("Attempted to free %d-byte block %p at %s:%d previously freed/realloced at %s:%d",
                       stb__alloc_history[n].size, p,
                       file, line,
                       stb__alloc_history[n].file, stb__alloc_history[n].line);
      else
         stb_fatal("Attempted to free unknown block %p at %s:%d", p, file,line);
   }
}

void stb_wrapper_check(void *p)
{
   int n;
   
   if (p == NULL) return;

   n = stb__hashfind(p);

   if (n >= 0) return;

   for (n=0; n < stb__alloc_size; ++n)
      if (stb__allocations[n].p == p)
         stb_fatal("Internal error: pointer %p was allocated, but hash search failed", p);

   // tried to free something that wasn't allocated!
   n = stb__historyfind(p);
   if (n >= 0)
      stb_fatal("Checked %d-byte block %p previously freed/realloced at %s:%d",
                    stb__alloc_history[n].size, p,
                    stb__alloc_history[n].file, stb__alloc_history[n].line);
   stb_fatal("Checked unknown block %p");
}

void stb_wrapper_realloc(void *p, void *q, int sz, char *file, int line)
{
   int n;
   if (p == NULL) { stb_wrapper_malloc(q, sz, file, line); return; }
   if (q == NULL) return; // nothing happened

   n = stb__hashfind(p);
   if (n == -1) {
      // tried to free something we hadn't allocated!
      // this is weird, though, because we got past the realloc!
      n = stb__historyfind(p);
      assert(0); /* NOTREACHED */
      if (n >= 0)
         stb_fatal("Attempted to realloc %d-byte block %p at %s:%d previously freed/realloced at %s:%d",
                       stb__alloc_history[n].size, p,
                       file, line,
                       stb__alloc_history[n].file, stb__alloc_history[n].line);
      else
         stb_fatal("Attempted to realloc unknown block %p at %s:%d", p, file,line);
   } else {
      if (q == p) {
         stb__allocations[n].size = sz;
         stb__allocations[n].file = file;
         stb__allocations[n].line = line;
      } else {
         stb__remove_alloc(n, file, line);
         stb__add_alloc(q,sz,file,line);
      }
   }
}

void stb_wrapper_listall(void (*func)(void *ptr, int sz, char *file, int line))
{
   int i;
   for (i=0; i < stb__alloc_size; ++i)
      if (stb__allocations[i].p > STB_DEL)
         func(stb__allocations[i].p   , stb__allocations[i].size,
              stb__allocations[i].file, stb__allocations[i].line);
}

void stb_wrapper_dump(char *filename)
{
   int i;
   FILE *f = fopen(filename, "w");
   if (!f) return;
   for (i=0; i < stb__alloc_size; ++i)
      if (stb__allocations[i].p > STB_DEL)
         fprintf(f, "%p %7d - %4d %s\n",
            stb__allocations[i].p   , stb__allocations[i].size,
            stb__allocations[i].line, stb__allocations[i].file);
}
#endif // STB_DEFINE


//////////////////////////////////////////////////////////////////////////////
//
//                  stb_pointer_set
//
//
// For data structures that support querying by key, data structure
// classes always hand-wave away the issue of what to do if two entries
// have the same key: basically, store a linked list of all the nodes
// which have the same key (a LISP-style list).
//
// The thing is, it's not that trivial. If you have an O(log n)
// lookup data structure, but then n/4 items have the same value,
// you don't want to spend O(n) time scanning that list when
// deleting an item if you already have a pointer to the item.
// (You have to spend O(n) time enumerating all the items with
// a given key, sure, and you can't accelerate deleting a particular
// item if you only have the key, not a pointer to the item.)
//
// I'm going to call this data structure, whatever it turns out to
// be, a "pointer set", because we don't store any associated data for
// items in this data structure, we just answer the question of
// whether an item is in it or not (it's effectively one bit per pointer).
// Technically they don't have to be pointers; you could cast ints
// to (void *) if you want, but you can't store 0 or 1 because of the
// hash table.
//
// Since the fastest data structure we might want to add support for
// identical-keys to is a hash table with O(1)-ish lookup time,
// that means that the conceptual "linked list of all items with
// the same indexed value" that we build needs to have the same
// performance; that way when we index a table we think is arbitrary
// ints, but in fact half of them are 0, we don't get screwed.
//
// Therefore, it needs to be a hash table, at least when it gets
// large. On the other hand, when the data has totally arbitrary ints
// or floats, there won't be many collisions, and we'll have tons of
// 1-item bitmaps. That will be grossly inefficient as hash tables;
// trade-off; the hash table is reasonably efficient per-item when
// it's large, but not when it's small. So we need to do something
// Judy-like and use different strategies depending on the size.
//
// Like Judy, we'll use the bottom bit to encode the strategy:
//
//      bottom bits:
//          00     -   direct tuple pointer
//          01     -   4-item bucket (16 bytes, no length, NULLs)
//          10     -   N-item array
//          11     -   hash table

typedef struct stb_ps stb_ps;

STB_EXTERN int      stb_ps_find  (stb_ps *ps, void *value);
STB_EXTERN stb_ps * stb_ps_add   (stb_ps *ps, void *value);
STB_EXTERN stb_ps * stb_ps_remove(stb_ps *ps, void *value);
STB_EXTERN stb_ps * stb_ps_remove_any(stb_ps *ps, void **value);
STB_EXTERN void     stb_ps_delete(stb_ps *ps);
STB_EXTERN int      stb_ps_count (stb_ps *ps);

STB_EXTERN stb_ps * stb_ps_copy  (stb_ps *ps);
STB_EXTERN int      stb_ps_subset(stb_ps *bigger, stb_ps *smaller);
STB_EXTERN int      stb_ps_eq    (stb_ps *p0, stb_ps *p1);

STB_EXTERN void ** stb_ps_getlist  (stb_ps *ps, int *count);
STB_EXTERN int     stb_ps_writelist(stb_ps *ps, void **list, int size );

// enum and fastlist don't allocate storage, but you must consume the
// list before there's any chance the data structure gets screwed up;
STB_EXTERN int     stb_ps_enum     (stb_ps *ps, void *data,
                                       int (*func)(void *value, void*data) );
STB_EXTERN void ** stb_ps_fastlist(stb_ps *ps, int *count);
//  result:
//     returns a list, *count is the length of that list,
//     but some entries of the list may be invalid;
//     test with 'stb_ps_fastlist_valid(x)'

#define stb_ps_fastlist_valid(x)   ((unsigned int) (x) > 1)

#ifdef STB_DEFINE

enum
{
   STB_ps_direct = 0,
   STB_ps_bucket = 1,
   STB_ps_array  = 2,
   STB_ps_hash   = 3,
};

#define STB_BUCKET_SIZE  4

typedef struct
{
   void *p[STB_BUCKET_SIZE];
} stb_ps_bucket;
#define GetBucket(p)    ((stb_ps_bucket *) ((char *) (p) - STB_ps_bucket))
#define EncodeBucket(p) ((stb_ps *) ((char *) (p) + STB_ps_bucket))

typedef char stb__verify_bucket_heap_size[sizeof(stb_ps_bucket) == 16];

static void stb_bucket_free(stb_ps_bucket *b)
{
   free(b);
}

static stb_ps_bucket *stb_bucket_create2(void *v0, void *v1)
{
   stb_ps_bucket *b = (stb_ps_bucket*) malloc(sizeof(*b));
   b->p[0] = v0;
   b->p[1] = v1;
   b->p[2] = NULL;
   b->p[3] = NULL;
   return b;
}

static stb_ps_bucket * stb_bucket_create3(void **v)
{
   stb_ps_bucket *b = (stb_ps_bucket*) malloc(sizeof(*b));
   b->p[0] = v[0];
   b->p[1] = v[1];
   b->p[2] = v[2];
   b->p[3] = NULL;
   return b;
}


// could use stb_arr, but this will save us memory
typedef struct
{
   int count;
   void *p[1];
} stb_ps_array;
#define GetArray(p)     ((stb_ps_array *) ((char *) (p) - STB_ps_array))
#define EncodeArray(p)  ((stb_ps *) ((char *) (p) + STB_ps_array))

static int stb_ps_array_max = 13;

typedef struct
{
   int size, mask;
   int count, count_deletes;
   int grow_threshhold;
   int shrink_threshhold;
   int rehash_threshhold;
   int any_offset;
   void *table[1];
} stb_ps_hash;
#define GetHash(p)      ((stb_ps_hash *) ((char *) (p) - STB_ps_hash))
#define EncodeHash(p)   ((stb_ps *) ((char *) (p) + STB_ps_hash))

#define stb_ps_empty(v)   (((uint32) v) <= 1)

static stb_ps_hash *stb_ps_makehash(int size, int old_size, void **old_data)
{
   int i;
   stb_ps_hash *h = (stb_ps_hash *) malloc(sizeof(*h) + (size-1) * sizeof(h->table[0]));
   assert(stb_is_pow2(size));
   h->size = size;
   h->mask = size-1;
   h->shrink_threshhold = (int) (0.3f * size);
   h->  grow_threshhold = (int) (0.8f * size);
   h->rehash_threshhold = (int) (0.9f * size);
   h->count = 0;
   h->count_deletes = 0;
   h->any_offset = 0;
   memset(h->table, 0, size * sizeof(h->table[0]));
   for (i=0; i < old_size; ++i)
      if (!stb_ps_empty(old_data[i]))
         stb_ps_add(EncodeHash(h), old_data[i]);
   return h;
}

void stb_ps_delete(stb_ps *ps)
{
   switch (3 & (int) ps) {
      case STB_ps_direct: break;
      case STB_ps_bucket: stb_bucket_free(GetBucket(ps)); break;
      case STB_ps_array : free(GetArray(ps)); break;
      case STB_ps_hash  : free(GetHash(ps)); break;
   }
}

stb_ps *stb_ps_copy(stb_ps *ps)
{
   int i;
   // not a switch: order based on expected performance/power-law distribution
   switch (3 & (int) ps) {
      case STB_ps_direct: return ps;
      case STB_ps_bucket: {
         stb_ps_bucket *n = (stb_ps_bucket *) malloc(sizeof(*n));
         *n = *GetBucket(ps);
         return EncodeBucket(n);
      }
      case STB_ps_array: {
         stb_ps_array *a = GetArray(ps);
         stb_ps_array *n = (stb_ps_array *) malloc(sizeof(*n) + stb_ps_array_max * sizeof(n->p[0]));
         n->count = a->count;
         for (i=0; i < a->count; ++i)
            n->p[i] = a->p[i];
         return EncodeArray(n);
      }
      case STB_ps_hash: {
         stb_ps_hash *h = GetHash(ps);
         stb_ps_hash *n = stb_ps_makehash(h->size, h->size, h->table);
         return EncodeHash(n);
      }
   }
   assert(0); /* NOTREACHED */
   return NULL;
}

int stb_ps_find(stb_ps *ps, void *value)
{
   int i, code = 3 & (int) ps;
    assert((3 & (int) value) == STB_ps_direct);
   assert(stb_ps_fastlist_valid(value));
   // not a switch: order based on expected performance/power-law distribution
   if (code == STB_ps_direct)
      return value == ps;
   if (code == STB_ps_bucket) {
      stb_ps_bucket *b = GetBucket(ps);
      assert(STB_BUCKET_SIZE == 4);
      if (b->p[0] == value || b->p[1] == value ||
          b->p[2] == value || b->p[3] == value)
          return TRUE;
      return FALSE;
   }
   if (code == STB_ps_array) {
      stb_ps_array *a = GetArray(ps);
      for (i=0; i < a->count; ++i)
         if (a->p[i] == value)
            return TRUE;
      return FALSE;
   } else {
      stb_ps_hash *h = GetHash(ps);
      uint32 hash = stb_hashptr(value);
      uint32 s, n = hash & h->mask;
      void **t = h->table;
      if (t[n] == value) return TRUE;
      if (t[n] == NULL) return FALSE;
      s = stb_rehash(hash) | 1;
      do {
         n = (n + s) & h->mask;
         if (t[n] == value) return TRUE;
      } while (t[n] != NULL);
      return FALSE;
   }
}

stb_ps *  stb_ps_add   (stb_ps *ps, void *value)
{
   #ifdef STB_DEBUG
   assert(!stb_ps_find(ps,value));
   #endif
   if (value == NULL) return ps; // ignore NULL adds to avoid bad breakage
   assert((3 & (int) value) == STB_ps_direct);
   assert(stb_ps_fastlist_valid(value));
   assert(value != STB_DEL);     // STB_DEL is less likely

   switch (3 & (int) ps) {
      case STB_ps_direct:
         if (ps == NULL) return (stb_ps *) value;
         return EncodeBucket(stb_bucket_create2(ps,value));

      case STB_ps_bucket: {
         stb_ps_bucket *b = GetBucket(ps);
         stb_ps_array  *a;
         assert(STB_BUCKET_SIZE == 4);
         if (b->p[0] == NULL) { b->p[0] = value; return ps; }
         if (b->p[1] == NULL) { b->p[1] = value; return ps; }
         if (b->p[2] == NULL) { b->p[2] = value; return ps; }
         if (b->p[3] == NULL) { b->p[3] = value; return ps; }
         a = (stb_ps_array *) malloc(sizeof(*a) + 7 * sizeof(a->p[0])); // 8 slots, must be 2^k
         memcpy(a->p, b, sizeof(*b));
         a->p[4] = value;
         a->count = 5;
         stb_bucket_free(b);
         return EncodeArray(a);
      }

      case STB_ps_array: {
         stb_ps_array *a = GetArray(ps);
         if (a->count == stb_ps_array_max) {
            // promote from array to hash
            stb_ps_hash *h = stb_ps_makehash(2 << stb_log2_ceil(a->count), a->count, a->p);
            free(a);
            return stb_ps_add(EncodeHash(h), value);
         }
         // do we need to resize the array? the array doubles in size when it
         // crosses a power-of-two
         if ((a->count & (a->count-1))==0) {
            int newsize = a->count*2;
            // clamp newsize to max if:
            //    1. it's larger than max
            //    2. newsize*1.5 is larger than max (to avoid extra resizing)
            if (newsize + a->count > stb_ps_array_max)
               newsize = stb_ps_array_max;
            a = (stb_ps_array *) realloc(a, sizeof(*a) + (newsize-1) * sizeof(a->p[0]));
         }
         a->p[a->count++] = value;
         return EncodeArray(a);
      }
      case STB_ps_hash: {
         stb_ps_hash *h = GetHash(ps);
         uint32 hash = stb_hashptr(value);
         uint32 n = hash & h->mask;
         void **t = h->table;
         // find first NULL or STB_DEL entry
         if (!stb_ps_empty(t[n])) {
            uint32 s = stb_rehash(hash) | 1;
            do {
               n = (n + s) & h->mask;
            } while (!stb_ps_empty(t[n]));
         }
         if (t[n] == STB_DEL)
            -- h->count_deletes;
         t[n] = value;
         ++ h->count;
         if (h->count == h->grow_threshhold) {
            stb_ps_hash *h2 = stb_ps_makehash(h->size*2, h->size, t);
            free(h);
            return EncodeHash(h2);
         }
         if (h->count + h->count_deletes == h->rehash_threshhold) {
            stb_ps_hash *h2 = stb_ps_makehash(h->size, h->size, t);
            free(h);
            return EncodeHash(h2);
         }
         return ps;
      }
   }
   return NULL; /* NOTREACHED */
}

stb_ps *stb_ps_remove(stb_ps *ps, void *value)
{
   #ifdef STB_DEBUG
   assert(stb_ps_find(ps, value));
   #endif
   assert((3 & (int) value) == STB_ps_direct);
   if (value == NULL) return ps; // ignore NULL removes to avoid bad breakage
   switch (3 & (int) ps) {
      case STB_ps_direct:
         return ps == value ? NULL : ps;
      case STB_ps_bucket: {
         stb_ps_bucket *b = GetBucket(ps);
         int count=0;
         assert(STB_BUCKET_SIZE == 4);
         if (b->p[0] == value) b->p[0] = NULL; else count += (b->p[0] != NULL);
         if (b->p[1] == value) b->p[1] = NULL; else count += (b->p[1] != NULL);
         if (b->p[2] == value) b->p[2] = NULL; else count += (b->p[2] != NULL);
         if (b->p[3] == value) b->p[3] = NULL; else count += (b->p[3] != NULL);
         if (count == 1) { // shrink bucket at size 1
            value = b->p[0];
            if (value == NULL) value = b->p[1];
            if (value == NULL) value = b->p[2];
            if (value == NULL) value = b->p[3];
            assert(value != NULL);
            stb_bucket_free(b);
            return (stb_ps *) value; // return STB_ps_direct of value
         }
         return ps;
      }
      case STB_ps_array: {
         stb_ps_array *a = GetArray(ps);
         int i;
         for (i=0; i < a->count; ++i) {
            if (a->p[i] == value) {
               a->p[i] = a->p[--a->count];
               if (a->count == 3) { // shrink to bucket!
                  stb_ps_bucket *b = stb_bucket_create3(a->p);
                  free(a);
                  return EncodeBucket(b);
               }
               return ps;
            }
         }
         return ps;
      }
      case STB_ps_hash: {
         stb_ps_hash *h = GetHash(ps);
         uint32 hash = stb_hashptr(value);
         uint32 s, n = hash & h->mask;
         void **t = h->table;
         if (t[n] != value) {
            s = stb_rehash(hash) | 1;
            do {
               n = (n + s) & h->mask;
            } while (t[n] != value);
         }
         t[n] = STB_DEL;
         -- h->count;
         ++ h->count_deletes;
         // should we shrink down to an array?
         if (h->count < stb_ps_array_max) {
            int n = 1 << stb_log2_floor(stb_ps_array_max);
            if (h->count < n) {
               stb_ps_array *a = (stb_ps_array *) malloc(sizeof(*a) + (n-1) * sizeof(a->p[0]));
               int i,j=0;
               for (i=0; i < h->size; ++i)
                  if (!stb_ps_empty(t[i]))
                     a->p[j++] = t[i];
               assert(j == h->count);
               a->count = j;
               free(h);
               return EncodeArray(a);
            }
         }
         if (h->count == h->shrink_threshhold) {
            stb_ps_hash *h2 = stb_ps_makehash(h->size >> 1, h->size, t);
            free(h);
            return EncodeHash(h2);
         }
         return ps;
      }
   }
   return ps; /* NOTREACHED */
}

stb_ps *stb_ps_remove_any(stb_ps *ps, void **value)
{
   assert(ps != NULL);
   switch (3 & (int) ps) {
      case STB_ps_direct:
         *value = ps;
         return NULL;
      case STB_ps_bucket: {
         stb_ps_bucket *b = GetBucket(ps);
         int count=0, slast=0, last=0;
         assert(STB_BUCKET_SIZE == 4);
         if (b->p[0]) { ++count;               last = 0; }
         if (b->p[1]) { ++count; slast = last; last = 1; }
         if (b->p[2]) { ++count; slast = last; last = 2; }
         if (b->p[3]) { ++count; slast = last; last = 3; }
         *value = b->p[last];
         b->p[last] = 0;
         if (count == 2) {
            void *leftover = b->p[slast]; // second to last
            stb_bucket_free(b);
            return (stb_ps *) leftover; 
         }
         return ps;
      }
      case STB_ps_array: {
         stb_ps_array *a = GetArray(ps);
         *value = a->p[a->count-1];
         if (a->count == 4)
            return stb_ps_remove(ps, *value);
         --a->count;
         return ps;
      }
      case STB_ps_hash: {
         stb_ps_hash *h = GetHash(ps);
         void **t = h->table;
         uint32 n = h->any_offset;
         while (stb_ps_empty(t[n]))
            n = (n + 1) & h->mask;
         *value = t[n];
         h->any_offset = (n+1) & h->mask;
         // check if we need to skip down to the previous type
         if (h->count-1 < stb_ps_array_max || h->count-1 == h->shrink_threshhold)
            return stb_ps_remove(ps, *value);
         t[n] = STB_DEL;
         -- h->count;
         ++ h->count_deletes;
         return ps;
      }
   }
   return ps; /* NOTREACHED */
}


void ** stb_ps_getlist(stb_ps *ps, int *count)
{
   int i,n=0;
   void **p;
   switch (3 & (int) ps) {
      case STB_ps_direct:
         if (ps == NULL) { *count = 0; return NULL; }
         p = (void **) malloc(sizeof(*p) * 1);
         p[0] = ps;
         *count = 1;
         return p;
      case STB_ps_bucket: {
         stb_ps_bucket *b = GetBucket(ps);
         p = (void **) malloc(sizeof(*p) * STB_BUCKET_SIZE);
         for (i=0; i < STB_BUCKET_SIZE; ++i)
            if (b->p[i] != NULL)
               p[n++] = b->p[i];
         break;
      }
      case STB_ps_array: {
         stb_ps_array *a = GetArray(ps);
         p = (void **) malloc(sizeof(*p) * a->count);
         memcpy(p, a->p, sizeof(*p) * a->count);
         *count = a->count;
         return p;
      }
      case STB_ps_hash: {
         stb_ps_hash *h = GetHash(ps);
         p = (void **) malloc(sizeof(*p) * h->count);
         for (i=0; i < h->size; ++i)
            if (!stb_ps_empty(h->table[i]))
               p[n++] = h->table[i];
         break;
      }
   }
   *count = n;
   return p;
}

int stb_ps_writelist(stb_ps *ps, void **list, int size )
{
   int i,n=0;
   switch (3 & (int) ps) {
      case STB_ps_direct:
         if (ps == NULL || size <= 0) return 0;
         list[0] = ps;
         return 1;
      case STB_ps_bucket: {
         stb_ps_bucket *b = GetBucket(ps);
         for (i=0; i < STB_BUCKET_SIZE; ++i)
            if (b->p[i] != NULL && n < size)
               list[n++] = b->p[i];
         return n;
      }
      case STB_ps_array: {
         stb_ps_array *a = GetArray(ps);
         n = stb_min(size, a->count);
         memcpy(list, a->p, sizeof(*list) * n);
         return n;
      }
      case STB_ps_hash: {
         stb_ps_hash *h = GetHash(ps);
         if (size <= 0) return 0;
         for (i=0; i < h->count; ++i) {
            if (!stb_ps_empty(h->table[i])) {
               list[n++] = h->table[i];
               if (n == size) break;
            }
         }
         return n;
      }
   }
   return 0; /* NOTREACHED */
}

int stb_ps_enum(stb_ps *ps, void *data, int (*func)(void *value, void *data))
{
   int i;
   switch (3 & (int) ps) {
      case STB_ps_direct:
         if (ps == NULL) return TRUE;
         return func(ps, data);
      case STB_ps_bucket: {
         stb_ps_bucket *b = GetBucket(ps);
         for (i=0; i < STB_BUCKET_SIZE; ++i)
            if (b->p[i] != NULL)
               if (!func(b->p[i], data))
                  return FALSE;
         return TRUE;
      }
      case STB_ps_array: {
         stb_ps_array *a = GetArray(ps);
         for (i=0; i < a->count; ++i)
            if (!func(a->p[i], data))
               return FALSE;
         return TRUE;
      }
      case STB_ps_hash: {
         stb_ps_hash *h = GetHash(ps);
         for (i=0; i < h->count; ++i)
            if (!stb_ps_empty(h->table[i]))
               if (!func(h->table[i], data))
                  return FALSE;
         return TRUE;
      }
   }
   return TRUE; /* NOTREACHED */
}

int stb_ps_count (stb_ps *ps)
{
   switch (3 & (int) ps) {
      case STB_ps_direct:
         return ps != NULL;
      case STB_ps_bucket: {
         stb_ps_bucket *b = GetBucket(ps);
         return (b->p[0] != NULL) + (b->p[1] != NULL) +
                (b->p[2] != NULL) + (b->p[3] != NULL);
      }
      case STB_ps_array: {
         stb_ps_array *a = GetArray(ps);
         return a->count;
      }
      case STB_ps_hash: {
         stb_ps_hash *h = GetHash(ps);
         return h->count;
      }
   }
   return 0;
}

void ** stb_ps_fastlist(stb_ps *ps, int *count)
{
   static void *storage;

   switch (3 & (int) ps) {
      case STB_ps_direct:
         if (ps == NULL) { *count = 0; return NULL; }
         storage = ps;
         *count = 1;
         return &storage;
      case STB_ps_bucket: {
         stb_ps_bucket *b = GetBucket(ps);
         *count = STB_BUCKET_SIZE;
         return b->p;
      }
      case STB_ps_array: {
         stb_ps_array *a = GetArray(ps);
         *count = a->count;
         return a->p;
      }
      case STB_ps_hash: {
         stb_ps_hash *h = GetHash(ps);
         *count = h->size;
         return h->table;
      }
   }
   return NULL; /* NOTREACHED */
}

int stb_ps_subset(stb_ps *bigger, stb_ps *smaller)
{
   int i, listlen;
   void **list = stb_ps_fastlist(smaller, &listlen);
   for(i=0; i < listlen; ++i)
      if (stb_ps_fastlist_valid(list[i]))
         if (!stb_ps_find(bigger, list[i]))
            return 0;
   return 1;
}

int stb_ps_eq(stb_ps *p0, stb_ps *p1)
{
   if (stb_ps_count(p0) != stb_ps_count(p1))
      return 0;
   return stb_ps_subset(p0, p1);
}

#undef GetBucket
#undef GetArray
#undef GetHash

#undef EncodeBucket
#undef EncodeArray
#undef EncodeHash

#endif


//////////////////////////////////////////////////////////////////////////////
//
//               Random Numbers via Meresenne Twister or LCG
//

STB_EXTERN unsigned long stb_srandLCG(unsigned long seed);
STB_EXTERN unsigned long stb_randLCG(void);
STB_EXTERN double        stb_frandLCG(void);

STB_EXTERN void          stb_srand(unsigned long seed);
STB_EXTERN unsigned long stb_rand(void);
STB_EXTERN double        stb_frand(void);
STB_EXTERN void          stb_shuffle(void *p, size_t n, size_t sz,
                                        unsigned long seed);
STB_EXTERN void stb_reverse(void *p, size_t n, size_t sz);

STB_EXTERN unsigned long stb_randLCG_explicit(unsigned long seed);

#define stb_rand_define(x,y)                                         \
                                                                     \
   unsigned long x(void)                                             \
   {                                                                 \
      static unsigned long stb__rand = y;                            \
      stb__rand = stb__rand * 2147001325 + 715136305; /* BCPL */     \
      return 0x31415926 ^ ((stb__rand >> 16) + (stb__rand << 16));   \
   }

#ifdef STB_DEFINE
unsigned long stb_randLCG_explicit(unsigned long seed)
{
   return seed * 2147001325 + 715136305;
}

static unsigned long stb__rand_seed=0;

unsigned long stb_srandLCG(unsigned long seed)
{
   unsigned long previous = stb__rand_seed;
   stb__rand_seed = seed;
   return previous;
}

unsigned long stb_randLCG(void)
{
   stb__rand_seed = stb__rand_seed * 2147001325 + 715136305; // BCPL generator
   // shuffle non-random bits to the middle, and xor to decorrelate with seed
   return 0x31415926 ^ ((stb__rand_seed >> 16) + (stb__rand_seed << 16));
}

double stb_frandLCG(void)
{
   return stb_randLCG() / ((double) (1 << 16) * (1 << 16));
}

void stb_shuffle(void *p, size_t n, size_t sz, unsigned long seed)
{
   char *a;
   unsigned long old_seed;
   int i;
   if (seed)
      old_seed = stb_srandLCG(seed);
   a = (char *) p + (n-1) * sz;

   for (i=n; i > 1; --i) {
      int j = stb_randLCG() % i;
      stb_swap(a, (char *) p + j * sz, sz);
      a -= sz;
   }
   if (seed)
      stb_srandLCG(old_seed);
}

void stb_reverse(void *p, size_t n, size_t sz)
{
   int i,j = n-1;
   for (i=0; i < j; ++i,--j) {
      stb_swap((char *) p + i * sz, (char *) p + j * sz, sz);
   }
}

// public domain Mersenne Twister by Michael Brundage
#define STB__MT_LEN       624

int stb__mt_index = STB__MT_LEN*sizeof(unsigned long)+1;
unsigned long stb__mt_buffer[STB__MT_LEN];

void stb_srand(unsigned long seed)
{
   int i;
   unsigned long old = stb_srandLCG(seed);
   for (i = 0; i < STB__MT_LEN; i++)
      stb__mt_buffer[i] = stb_randLCG();
   stb_srandLCG(old);
   stb__mt_index = STB__MT_LEN*sizeof(unsigned long);
}

#define STB__MT_IA           397
#define STB__MT_IB           (STB__MT_LEN - STB__MT_IA)
#define STB__UPPER_MASK      0x80000000
#define STB__LOWER_MASK      0x7FFFFFFF
#define STB__MATRIX_A        0x9908B0DF
#define STB__TWIST(b,i,j)    ((b)[i] & STB__UPPER_MASK) | ((b)[j] & STB__LOWER_MASK)
#define STB__MAGIC(s)        (((s)&1)*STB__MATRIX_A)

unsigned long stb_rand()
{
   unsigned long * b = stb__mt_buffer;
   int idx = stb__mt_index;
   unsigned long s,r;
   int i;
	
   if (idx >= STB__MT_LEN*sizeof(unsigned long)) {
      if (idx > STB__MT_LEN*sizeof(unsigned long))
         stb_srand(0);
      idx = 0;
      i = 0;
      for (; i < STB__MT_IB; i++) {
         s = STB__TWIST(b, i, i+1);
         b[i] = b[i + STB__MT_IA] ^ (s >> 1) ^ STB__MAGIC(s);
      }
      for (; i < STB__MT_LEN-1; i++) {
         s = STB__TWIST(b, i, i+1);
         b[i] = b[i - STB__MT_IB] ^ (s >> 1) ^ STB__MAGIC(s);
      }
      
      s = STB__TWIST(b, STB__MT_LEN-1, 0);
      b[STB__MT_LEN-1] = b[STB__MT_IA-1] ^ (s >> 1) ^ STB__MAGIC(s);
   }
   stb__mt_index = idx + sizeof(unsigned long);
   
   r = *(unsigned long *)((unsigned char *)b + idx);
   
   r ^= (r >> 11);
   r ^= (r << 7) & 0x9D2C5680;
   r ^= (r << 15) & 0xEFC60000;
   r ^= (r >> 18);
   
   return r;
}

double stb_frand(void)
{
   return stb_rand() / ((double) (1 << 16) * (1 << 16));
}

#endif


//////////////////////////////////////////////////////////////////////////////
//
//                        stb_dupe
//
// stb_dupe is a duplicate-finding system for very, very large data
// structures--large enough that sorting is too slow, but not so large
// that we can't keep all the data in memory. using it works as follows:
//
//     1. create an stb_dupe:
//          provide a hash function
//          provide an equality function
//          provide an estimate for the size
//          optionally provide a comparison function
//
//     2. traverse your data, 'adding' pointers to the stb_dupe
//
//     3. finish and ask for duplicates
//
//        the stb_dupe will discard its intermediate data and build
//        a collection of sorted lists of duplicates, with non-duplicate
//        entries omitted entirely
//
//
//  Implementation strategy:
//
//     while collecting the N items, we keep a hash table of approximate
//     size sqrt(N). (if you tell use the N up front, the hash table is
//     just that size exactly)
//
//     each entry in the hash table is just an stb__arr of pointers (no need
//     to use stb_ps, because we don't need to delete from these)
//
//     for step 3, for each entry in the hash table, we apply stb_dupe to it
//     recursively. once the size gets small enough (or doesn't decrease
//     significantly), we switch to either using qsort() on the comparison
//     function, or else we just do the icky N^2 gather


typedef struct stb_dupe stb_dupe;

typedef int (*stb_compare_func)(void *a, void *b);
typedef int (*stb_hash_func)(void *a, unsigned int seed);

STB_EXTERN void stb_dupe_free(stb_dupe *sd);
STB_EXTERN stb_dupe *stb_dupe_create(stb_hash_func hash,
                          stb_compare_func eq, int size, stb_compare_func ineq);
STB_EXTERN void stb_dupe_add(stb_dupe *sd, void *item);
STB_EXTERN void stb_dupe_finish(stb_dupe *sd);
STB_EXTERN int stb_dupe_numsets(stb_dupe *sd);
STB_EXTERN void **stb_dupe_set(stb_dupe *sd, int num);
STB_EXTERN int stb_dupe_set_count(stb_dupe *sd, int num);

#ifdef STB_DEFINE

struct stb_dupe
{
   STB__ARR(void *) *hash_table;
   int hash_size;
   int size_log2;
   int population;

   int hash_shift;
   stb_hash_func     hash;

   stb_compare_func  eq;
   stb_compare_func  ineq;

   STB__ARR(STB__ARR(void*)) dupes;
};

int stb_dupe_numsets(stb_dupe *sd)
{
   assert(sd->hash_table == NULL);
   return stb_arr_len(sd->dupes);
}

void **stb_dupe_set(stb_dupe *sd, int num)
{
   assert(sd->hash_table == NULL);
   return sd->dupes[num];
}

int stb_dupe_set_count(stb_dupe *sd, int num)
{
   assert(sd->hash_table == NULL);
   return stb_arr_len(sd->dupes[num]);
}

stb_dupe *stb_dupe_create(stb_hash_func hash, stb_compare_func eq, int size,
                                              stb_compare_func ineq)
{
   int i, hsize;
   stb_dupe *sd = (stb_dupe *) malloc(sizeof(*sd));

   sd->size_log2 = 4;
   hsize = 1 << sd->size_log2;
   while (hsize * hsize < size) {
      ++sd->size_log2;
      hsize *= 2;
   }

   sd->hash = hash;
   sd->eq   = eq;
   sd->ineq = ineq;
   sd->hash_shift = 0;

   sd->population = 0;
   sd->hash_size = hsize;
   sd->hash_table = (STB__ARR(void *)*) malloc(sizeof(*sd->hash_table) * hsize);
   for (i=0; i < hsize; ++i)
      sd->hash_table[i] = NULL;

   sd->dupes = NULL;

   return sd;
}

void stb_dupe_add(stb_dupe *sd, void *item)
{
   uint32 hash = sd->hash(item, sd->hash_shift);
   int z = hash & (sd->hash_size-1);
   stb_arr_push(sd->hash_table[z], item);
   ++sd->population;
}

void stb_dupe_free(stb_dupe *sd)
{
   int i;
   for (i=0; i < stb_arr_len(sd->dupes); ++i)
      if (sd->dupes[i])
         stb_arr_free(sd->dupes[i]);
   stb_arr_free(sd->dupes);
   free(sd);
}

static stb_compare_func stb__compare;

static int stb__dupe_compare(const void *a, const void *b)
{
   void *p = *(void **) a;
   void *q = *(void **) b;

   return stb__compare(p,q);
}

void stb_dupe_finish(stb_dupe *sd)
{
   int i,j,k;
   assert(sd->dupes == NULL);
   for (i=0; i < sd->hash_size; ++i) {
      STB__ARR(void *) list = sd->hash_table[i];
      if (list != NULL) {                                          
         int n = stb_arr_len(list);
         // @TODO: measure to find good numbers instead of just making them up!
         int thresh = (sd->ineq ? 200 : 20);
         // if n is large enough to be worth it, and n is smaller than
         // before (so we can guarantee we'll use a smaller hash table);
         // and there are enough hash bits left, assuming full 32-bit hash
         if (n > thresh && n < (sd->population >> 3) && sd->hash_shift + sd->size_log2*2 < 32) {

            // recursively process this row using stb_dupe, O(N log log N)

            stb_dupe *d = stb_dupe_create(sd->hash, sd->eq, n, sd->ineq);
            d->hash_shift = stb_randLCG_explicit(sd->hash_shift);
            for (j=0; j < n; ++j)
               stb_dupe_add(d, list[j]);
            sd->hash_table[i] = stb_arr_free(sd->hash_table[i]);
            stb_dupe_finish(d);
            for (j=0; j < stb_arr_len(d->dupes); ++j) {
               stb_arr_push(sd->dupes, d->dupes[j]);
               d->dupes[j] = NULL; // take over ownership
            }
            stb_dupe_free(d);

         } else if (sd->ineq) {

            // process this row using qsort(), O(N log N)
            stb__compare = sd->ineq;
            qsort(list, n, sizeof(list[0]), stb__dupe_compare);

            // find equal subsequences of the list
            for (j=0; j < n-1; ) {
               // find a subsequence from j..k
               for (k=j; k < n; ++k)
                  // only use ineq so eq can be left undefined
                  if (sd->ineq(list[j], list[k]))
                     break;
               // k is the first one not in the subsequence
               if (k-j > 1) {
                  STB__ARR(void *) mylist = NULL;
                  stb_arr_setlen(mylist, k-j);
                  memcpy(mylist, list+j, sizeof(list[j]) * (k-j));
                  stb_arr_push(sd->dupes, mylist);
               }
               j = k;
            }
            sd->hash_table[i] = stb_arr_free(sd->hash_table[i]);
         } else {

            // process this row using eq(), O(N^2)
            for (j=0; j < n; ++j) {
               if (list[j] != NULL) {
                  STB__ARR(void *) output  = NULL;
                  for (k=j+1; k < n; ++k) {
                     if (sd->eq(list[j], list[k])) {
                        if (output == NULL)
                           stb_arr_push(output, list[j]);
                        stb_arr_push(output, list[k]);
                        list[k] = NULL;
                     }
                  }
                  list[j] = NULL;
                  if (output)
                     stb_arr_push(sd->dupes, output);
               }
            }
            sd->hash_table[i] = stb_arr_free(sd->hash_table[i]);
         }
      }
   }
   free(sd->hash_table);
   sd->hash_table = NULL;
}
#endif

//////////////////////////////////////////////////////////////////////////////
//
//                       templatized Sort routine
//
// This is an attempt to implement a templated sorting algorithm.
// To use it, you have to explicitly instantiate it as a _function_,
// then you call that function. This allows the comparison to be inlined,
// giving the sort similar performance to C++ sorts.
//
// It implements quicksort with three-way-median partitioning (generally
// well-behaved), with a final insertion sort pass.
//
// When you define the compare expression, you should assume you have
// elements of your array pointed to by 'a' and 'b', and perform the comparison
// on those. OR you can use one or more statements; first say '0;', then
// write whatever code you want, and compute the result into a variable 'c'.

#define stb_declare_sort(FUNCNAME, TYPE)    \
                       void FUNCNAME(TYPE *p, int n)
#define stb_define_sort(FUNCNAME,TYPE,COMPARE) \
                       stb__define_sort(       void, FUNCNAME,TYPE,COMPARE)
#define stb_define_sort_static(FUNCNAME,TYPE,COMPARE) \
                       stb__define_sort(static void, FUNCNAME,TYPE,COMPARE)

#define stb__define_sort(MODE, FUNCNAME, TYPE, COMPARE)                       \
                                                                              \
void STB_(FUNCNAME,_ins_sort)(TYPE *p, int n)                          \
{                                                                             \
   int i,j;                                                                   \
   for (i=1; i < n; ++i) {                                                    \
      TYPE t = p[i], *a = &t;                                                 \
      j = i;                                                                  \
      while (j > 0) {                                                         \
         TYPE *b = &p[j-1];                                                   \
         int c = COMPARE;                                                     \
         if (!c) break;                                                       \
         p[j] = p[j-1];                                                       \
         --j;                                                                 \
      }                                                                       \
      if (i != j)                                                             \
         p[j] = t;                                                            \
   }                                                                          \
}                                                                             \
                                                                              \
void STB_(FUNCNAME,_quicksort)(TYPE *p, int n)                         \
{                                                                             \
   /* threshhold for transitioning to insertion sort */                       \
   while (n > 12) {                                                           \
      TYPE *a,*b,t;                                                           \
      int c01,c12,c,m,i,j;                                                    \
                                                                              \
      /* compute median of three */                                           \
      m = n >> 1;                                                             \
      a = &p[0];                                                              \
      b = &p[m];                                                              \
      c = COMPARE;                                                            \
      c01 = c;                                                                \
      a = &p[m];                                                              \
      b = &p[n-1];                                                            \
      c = COMPARE;                                                            \
      c12 = c;                                                                \
      /* if 0 >= mid >= end, or 0 < mid < end, then use mid */                \
      if (c01 != c12) {                                                       \
         /* otherwise, we'll need to swap something else to middle */         \
         int z;                                                               \
         a = &p[0];                                                           \
         b = &p[n-1];                                                         \
         c = COMPARE;                                                         \
         /* 0>mid && mid<n:  0>n => n; 0<n => 0 */                            \
         /* 0<mid && mid>n:  0>n => 0; 0<n => n */                            \
         z = (c == c12) ? 0 : n-1;                                            \
         t = p[z];                                                            \
         p[z] = p[m];                                                         \
         p[m] = t;                                                            \
      }                                                                       \
      /* now p[m] is the median-of-three */                                   \
      /* swap it to the beginning so it won't move around */                  \
      t = p[0];                                                               \
      p[0] = p[m];                                                            \
      p[m] = t;                                                               \
                                                                              \
      /* partition loop */                                                    \
      i=1;                                                                    \
      j=n-1;                                                                  \
      for(;;) {                                                               \
         /* handling of equality is crucial here */                           \
         /* for sentinels & efficiency with duplicates */                     \
         b = &p[0];                                                           \
         for (;;++i) {                                                        \
            a=&p[i];                                                          \
            c = COMPARE;                                                      \
            if (!c) break;                                                    \
         }                                                                    \
         a = &p[0];                                                           \
         for (;;--j) {                                                        \
            b=&p[j];                                                          \
            c = COMPARE;                                                      \
            if (!c) break;                                                    \
         }                                                                    \
         /* make sure we haven't crossed */                                   \
         if (i >= j) break;                                                   \
         t = p[i];                                                            \
         p[i] = p[j];                                                         \
         p[j] = t;                                                            \
                                                                              \
         ++i;                                                                 \
         --j;                                                                 \
      }                                                                       \
      /* recurse on smaller side, iterate on larger */                        \
      if (j < (n-i)) {                                                        \
         STB_(FUNCNAME,_quicksort)(p,j);                                       \
         p = p+i;                                                             \
         n = n-i;                                                             \
      } else {                                                                \
         STB_(FUNCNAME,_quicksort)(p+i, n-i);                                  \
         n = j;                                                               \
      }                                                                       \
   }                                                                          \
}                                                                             \
                                                                              \
MODE FUNCNAME(TYPE *p, int n)                                                 \
{                                                                             \
   STB_(FUNCNAME, _quicksort)(p, n);                                           \
   STB_(FUNCNAME, _ins_sort)(p, n);                                            \
}                                                                             \


//////////////////////////////////////////////////////////////////////////////
//
//      stb_bitset   an array of booleans indexed by integers
//

typedef stb_uint32 stb_bitset;

STB_EXTERN  stb_bitset *stb_bitset_new(int value, int len);

#define stb_bitset_clearall(arr,len)     (memset(arr,   0, 4 * (len)))
#define stb_bitset_setall(arr,len)       (memset(arr, 255, 4 * (len)))

#define stb_bitset_setbit(arr,n)         ((arr)[(n) >> 5] |=  (1 << (n & 31)))
#define stb_bitset_clearbit(arr,n)       ((arr)[(n) >> 5] &= ~(1 << (n & 31)))
#define stb_bitset_testbit(arr,n)        ((arr)[(n) >> 5] &   (1 << (n & 31)))

STB_EXTERN  stb_bitset *stb_bitset_union(stb_bitset *p0, stb_bitset *p1, int len);

STB_EXTERN  int *stb_bitset_getlist(stb_bitset *out, int start, int end);

STB_EXTERN  int  stb_bitset_eq(stb_bitset *p0, stb_bitset *p1, int len);
STB_EXTERN  int  stb_bitset_disjoint(stb_bitset *p0, stb_bitset *p1, int len);
STB_EXTERN  int  stb_bitset_disjoint_0(stb_bitset *p0, stb_bitset *p1, int len);
STB_EXTERN  int  stb_bitset_subset(stb_bitset *bigger, stb_bitset *smaller, int len);
STB_EXTERN  int  stb_bitset_unioneq_changed(stb_bitset *p0, stb_bitset *p1, int len);

#ifdef STB_DEFINE
int stb_bitset_eq(stb_bitset *p0, stb_bitset *p1, int len)
{
   int i;
   for (i=0; i < len; ++i)
      if (p0[i] != p1[i]) return 0;
   return 1;
}

int stb_bitset_disjoint(stb_bitset *p0, stb_bitset *p1, int len)
{
   int i;
   for (i=0; i < len; ++i)
      if (p0[i] & p1[i]) return 0;
   return 1;
}

int stb_bitset_disjoint_0(stb_bitset *p0, stb_bitset *p1, int len)
{
   int i;
   for (i=0; i < len; ++i)
      if ((p0[i] | p1[i]) != 0xffffffff) return 0;
   return 1;
}

int stb_bitset_subset(stb_bitset *bigger, stb_bitset *smaller, int len)
{
   int i;
   for (i=0; i < len; ++i)
      if ((bigger[i] & smaller[i]) != smaller[i]) return 0;
   return 1;
}

stb_bitset *stb_bitset_union(stb_bitset *p0, stb_bitset *p1, int len)
{
   int i;
   stb_bitset *d = (stb_bitset *) malloc(sizeof(*d) * len);
   for (i=0; i < len; ++i) d[i] = p0[i] | p1[i];
   return d;
}

int stb_bitset_unioneq_changed(stb_bitset *p0, stb_bitset *p1, int len)
{
   int i, changed=0;
   for (i=0; i < len; ++i) {
      stb_bitset d = p0[i] | p1[i];
      if (d != p0[i]) {
         p0[i] = d;
         changed = 1;
      }
   }
   return changed;
}

stb_bitset *stb_bitset_new(int value, int len)
{
   int i;
   stb_bitset *d = (stb_bitset *) malloc(sizeof(*d) * len);
   if (value) value = 0xffffffff;
   for (i=0; i < len; ++i) d[i] = value;
   return d;
}

int *stb_bitset_getlist(stb_bitset *out, int start, int end)
{
   STB__ARR(int) list = NULL;
   int i;
   for (i=start; i < end; ++i)
      if (stb_bitset_testbit(out, i))
         stb_arr_push(list, i);
   return list;
}
#endif

//////////////////////////////////////////////////////////////////////////////
//
//      stb_wordwrap    quality word-wrapping for fixed-width fonts
//

STB_EXTERN int stb_wordwrap(int *pairs, int pair_max, int count, char *str);
STB_EXTERN int *stb_wordwrapalloc(int count, char *str);

#ifdef STB_DEFINE

int stb_wordwrap(int *pairs, int pair_max, int count, char *str)
{
   int n=0,i=0, start=0,nonwhite=0;
   if (pairs == NULL) pair_max = 0x7ffffff0;
   else pair_max *= 2;
   // parse 
   for(;;) {
      int s=i; // first whitespace char; last nonwhite+1
      int w;   // word start
      // accept whitespace
      while (isspace(str[i])) {
         if (str[i] == '\n' || str[i] == '\r') {
            if (str[i] + str[i+1] == '\n' + '\r') ++i;
            if (n >= pair_max) return -1;
            if (pairs) pairs[n] = start, pairs[n+1] = s-start;
            n += 2;
            nonwhite=0;
            start = i+1;
            s = start;
         }
         ++i;
      }
      if (i >= start+count) {
         // we've gone off the end using whitespace
         if (nonwhite) {
            if (n >= pair_max) return -1;
            if (pairs) pairs[n] = start, pairs[n+1] = s-start;
            n += 2;
            start = s = i;
            nonwhite=0;
         } else {
            // output all the whitespace
            while (i >= start+count) {
               if (n >= pair_max) return -1;
               if (pairs) pairs[n] = start, pairs[n+1] = count;
               n += 2;
               start += count;
            }
            s = start;
         }
      }

      if (str[i] == 0) break;
      // now scan out a word and see if it fits
      w = i;
      while (str[i] && !isspace(str[i])) {
         ++i;
      }
      // wrapped?
      if (i > start + count) {
         // huge?
         if (i-s <= count) {
            if (n >= pair_max) return -1;
            if (pairs) pairs[n] = start, pairs[n+1] = s-start;
            n += 2;
            start = w;
         } else {
            // This word is longer than one line. If we wrap it onto N lines
            // there are leftover chars. do those chars fit on the cur line?
            // But if we have leading whitespace, we force it to start here.
            if ((w-start) + ((i-w) % count) <= count || !nonwhite) {
               // output a full line
               if (n >= pair_max) return -1;
               if (pairs) pairs[n] = start, pairs[n+1] = count;
               n += 2;
               start += count;
               w = start;
            } else {
               // output a partial line, trimming trailing whitespace
               if (s != start) {
                  if (n >= pair_max) return -1;
                  if (pairs) pairs[n] = start, pairs[n+1] = s-start;
                  n += 2;
                  start = w;
               }
            }
            // now output full lines as needed
            while (start + count <= i) {
               if (n >= pair_max) return -1;
               if (pairs) pairs[n] = start, pairs[n+1] = count;
               n += 2;
               start += count;
            }
         }
      }
      nonwhite=1;
   }
   if (start < i) {
      if (n >= pair_max) return -1;
      if (pairs) pairs[n] = start, pairs[n+1] = i-start;
      n += 2;
   }
   return n>>1;
}

int *stb_wordwrapalloc(int count, char *str)
{
   int n = stb_wordwrap(NULL,0,count,str);
   STB__ARR(int ) z = NULL;
   stb_arr_setlen(z, n*2);
   stb_wordwrap(z, n, count, str);
   return z;
}
#endif


//////////////////////////////////////////////////////////////////////////////
//
//         stb_match:    wildcards and regexping
//

STB_EXTERN int stb_wildmatch (char *expr, char *candidate);
STB_EXTERN int stb_wildmatchi(char *expr, char *candidate);
STB_EXTERN int stb_wildfind  (char *expr, char *candidate);
STB_EXTERN int stb_wildfindi (char *expr, char *candidate);

STB_EXTERN int stb_regex(char *regex, char *candidate);

typedef struct stb_matcher stb_matcher;

STB_EXTERN stb_matcher *stb_regex_matcher(char *regex);
STB_EXTERN int stb_matcher_match(stb_matcher *m, char *str);
STB_EXTERN int stb_matcher_find(stb_matcher *m, char *str);
STB_EXTERN void stb_matcher_free(stb_matcher *f);

STB_EXTERN stb_matcher *stb_lex_matcher(void);
STB_EXTERN int stb_lex_item(stb_matcher *m, char *str, int result);
STB_EXTERN int stb_lex_item_wild(stb_matcher *matcher, char *regex, int result);
STB_EXTERN int stb_lex(stb_matcher *m, char *str, int *len);



#ifdef STB_DEFINE

static int stb__match_qstring(char *candidate, char *qstring, int qlen, int insensitive)
{
   int i;
   if (insensitive) {
      for (i=0; i < qlen; ++i)
         if (qstring[i] == '?') {
            if (!candidate[i]) return 0;
         } else
            if (tolower(qstring[i]) != tolower(candidate[i]))
               return 0;
   } else {
      for (i=0; i < qlen; ++i)
         if (qstring[i] == '?') {
            if (!candidate[i]) return 0;
         } else
            if (qstring[i] != candidate[i])
               return 0;
   }
   return 1;
}

static int stb__find_qstring(char *candidate, char *qstring, int qlen, int insensitive)
{
   char c;

   int offset=0;
   while (*qstring == '?') {
      ++qstring;
      --qlen;
      ++candidate;
      if (qlen == 0) return 0;
      if (*candidate == 0) return -1;
   }

   c = *qstring++;
   --qlen;
   if (insensitive) c = tolower(c);

   while (candidate[offset]) {
      if (c == (insensitive ? tolower(candidate[offset]) : candidate[offset]))
         if (stb__match_qstring(candidate+offset+1, qstring, qlen, insensitive))
            return offset;
      ++offset;
   }

   return -1;
}

int stb__wildmatch_raw2(char *expr, char *candidate, int search, int insensitive)
{
   int where=0;
   int start = -1;
   
   if (!search) {
      // parse to first '*'
      if (*expr != '*')
         start = 0;
      while (*expr != '*') {
         if (!*expr)
            return *candidate == 0 ? 0 : -1;
         if (*expr == '?') {
            if (!*candidate) return -1;
         } else {
            if (insensitive) {
               if (tolower(*candidate) != tolower(*expr))
                  return -1;
            } else 
               if (*candidate != *expr)
                  return -1;
         }
         ++candidate, ++expr, ++where;
      }
   } else {
      // 0-length search string
      if (!*expr)
         return 0;
   }

   assert(search || *expr == '*');
   if (!search)
      ++expr;

   // implicit '*' at this point
      
   while (*expr) {
      int o=0;
      // combine redundant * characters
      while (expr[0] == '*') ++expr;

      // ok, at this point, expr[-1] == '*',
      // and expr[0] != '*'

      if (!expr[0]) return start >= 0 ? start : 0;

      // now find next '*'
      o = 0;
      while (expr[o] != '*') {
         if (expr[o] == 0)
            break;
         ++o;
      }
      // if no '*', scan to end, then match at end
      if (expr[o] == 0 && !search) {
         int z;
         for (z=0; z < o; ++z)
            if (candidate[z] == 0)
               return -1;
         while (candidate[z])
            ++z;
         // ok, now check if they match
         if (stb__match_qstring(candidate+z-o, expr, o, insensitive))
            return start >= 0 ? start : 0;
         return -1; 
      } else {
         // if yes '*', then do stb__find_qmatch on the intervening chars
         int n = stb__find_qstring(candidate, expr, o, insensitive);
         if (n < 0)
            return -1;
         if (start < 0)
            start = where + n;
         expr += o;
         candidate += n+o;
      }

      if (*expr == 0) {
         assert(search);
         return start;
      }

      assert(*expr == '*');
      ++expr;
   }

   return start >= 0 ? start : 0;
}

int stb__wildmatch_raw(char *expr, char *candidate, int search, int insensitive)
{
   char buffer[256];
   // handle multiple search strings
   char *s = strchr(expr, ';');
   char *last = expr;
   while (s) {
      int z;
      // need to allow for non-writeable strings... assume they're small
      if (s - last < 256) {
         stb_strncpy(buffer, last, s-last+1);
         z = stb__wildmatch_raw2(buffer, candidate, search, insensitive);
      } else {
         *s = 0;
         z = stb__wildmatch_raw2(last, candidate, search, insensitive);
         *s = ';';
      }
      if (z >= 0) return z;
      last = s+1;
      s = strchr(last, ';');
   }
   return stb__wildmatch_raw2(last, candidate, search, insensitive);
}

int stb_wildmatch(char *expr, char *candidate)
{
   return stb__wildmatch_raw(expr, candidate, 0,0) >= 0;
}

int stb_wildmatchi(char *expr, char *candidate)
{
   return stb__wildmatch_raw(expr, candidate, 0,1) >= 0;
}

int stb_wildfind(char *expr, char *candidate)
{
   return stb__wildmatch_raw(expr, candidate, 1,0);
}

int stb_wildfindi(char *expr, char *candidate)
{
   return stb__wildmatch_raw(expr, candidate, 1,1);
}

typedef struct
{
   int16 transition[256];
} stb_dfa;

// an NFA node represents a state you're in; it then has
// an arbitrary number of edges dangling off of it
// note this isn't utf8-y
typedef struct
{
   int16  match; // character/set to match
   uint16 node;  // output node to go to
} stb_nfa_edge;

typedef struct
{
   int16 goal;   // does reaching this win the prize?
   uint8 active; // is this in the active list
   STB__ARR(stb_nfa_edge) out;
   STB__ARR(uint16)       eps;  // list of epsilon closures
} stb_nfa_node;

#define STB__DFA_UNDEF  -1
#define STB__DFA_GOAL   -2
#define STB__DFA_END    -3
#define STB__DFA_MGOAL  -4
#define STB__DFA_VALID  0

#define STB__NFA_STOP_GOAL -1

// compiled regexp
struct stb_matcher
{
   uint16 start_node;
   int16 dfa_start;
   uint32 *charset;
   int num_charset;
   int match_start;
   STB__ARR(stb_nfa_node) nodes;
   int does_lex;

   // dfa matcher
   STB__ARR(stb_dfa) dfa;
   STB__ARR(uint32 ) dfa_mapping;
   STB__ARR(int16  ) dfa_result;
   int num_words_per_dfa;
};

static int stb__add_node(stb_matcher *matcher)
{
   stb_nfa_node z;
   z.active = 0;
   z.eps    = 0;
   z.goal   = 0;
   z.out    = 0;
   stb_arr_push(matcher->nodes, z);
   return stb_arr_len(matcher->nodes)-1;
}

static void stb__add_epsilon(stb_matcher *matcher, int from, int to)
{
   assert(from != to);
   if (matcher->nodes[from].eps == NULL)
      stb_arr_malloc((void **) &matcher->nodes[from].eps, matcher);
   stb_arr_push(matcher->nodes[from].eps, to);
}

static void stb__add_edge(stb_matcher *matcher, int from, int to, int type)
{
   stb_nfa_edge z = { type, to };
   if (matcher->nodes[from].out == NULL)
      stb_arr_malloc((void **) &matcher->nodes[from].out, matcher);
   stb_arr_push(matcher->nodes[from].out, z);
}

static char *stb__reg_parse_alt(stb_matcher *m, int s, char *r, uint16 *e);
static char *stb__reg_parse(stb_matcher *matcher, int start, char *regex, uint16 *end)
{
   int n;
   int last_start = -1;
   uint16 last_end = start;

   while (*regex) {
      switch (*regex) {
         case '(':
            last_start = last_end;
            regex = stb__reg_parse_alt(matcher, last_end, regex+1, &last_end);
            if (regex == NULL || *regex != ')')
               return NULL;
            ++regex;
            break;

         case '|':
         case ')':
            *end = last_end;
            return regex;

         case '?':
            if (last_start < 0) return NULL;
            stb__add_epsilon(matcher, last_start, last_end);
            ++regex;
            break;

         case '*':
            if (last_start < 0) return NULL;
            stb__add_epsilon(matcher, last_start, last_end);

            // fall through

         case '+':
            if (last_start < 0) return NULL;
            stb__add_epsilon(matcher, last_end, last_start);
            // prevent links back to last_end from chaining to last_start
            n = stb__add_node(matcher);
            stb__add_epsilon(matcher, last_end, n);
            last_end = n;
            ++regex;
            break;

         case '{':   // not supported!
            // @TODO: given {n,m}, clone last_start to last_end m times,
            // and include epsilons from start to first m-n blocks
            return NULL; 

         case '\\':
            ++regex;
            if (!*regex) return NULL;

            // fallthrough
         default: // match exactly this character
            n = stb__add_node(matcher);
            stb__add_edge(matcher, last_end, n, *regex);
            last_start = last_end;
            last_end = n;
            ++regex;
            break;

         case '$':
            n = stb__add_node(matcher);
            stb__add_edge(matcher, last_end, n, '\n');
            last_start = last_end;
            last_end = n;
            ++regex;
            break;

         case '.':
            n = stb__add_node(matcher);
            stb__add_edge(matcher, last_end, n, -1);
            last_start = last_end;
            last_end = n;
            ++regex;
            break;

         case '[': {
            uint8 flags[256];
            int invert = 0,z;
            ++regex;
            if (matcher->num_charset == 0) {
               matcher->charset = (stb_uint *) stb_malloc(matcher, sizeof(*matcher->charset) * 256);
               memset(matcher->charset, 0, sizeof(*matcher->charset) * 256);
            }

            memset(flags,0,sizeof(flags));

            // leading ^ is special
            if (*regex == '^')
               ++regex, invert = 1;

            // leading ] is special
            if (*regex == ']') {
               flags[']'] = 1;
               ++regex;
            }
            while (*regex != ']') {
               uint a;
               if (!*regex) return NULL;
               a = *regex++;
               if (regex[0] == '-' && regex[1] != ']') {
                  uint i,b = regex[1];
                  regex += 2;
                  if (b == 0) return NULL;
                  if (a > b) return NULL;
                  for (i=a; i <= b; ++i)
                     flags[i] = 1;
               } else
                  flags[a] = 1;
            }
            ++regex;
            if (invert) {
               int i;
               for (i=0; i < 256; ++i)
                  flags[i] = 1-flags[i];
            }

            // now check if any existing charset matches
            for (z=0; z < matcher->num_charset; ++z) {
               int i, k[2] = { 0, 1 << z};
               for (i=0; i < 256; ++i) {
                  unsigned int f = k[flags[i]];
                  if ((matcher->charset[i] & k[1]) != f)
                     break;
               }
               if (i == 256) break;
            }

            if (z == matcher->num_charset) {
               int i;
               ++matcher->num_charset;
               if (matcher->num_charset > 32) {
                  assert(0); /* NOTREACHED */
                  return NULL; // too many charsets, oops
               }
               for (i=0; i < 256; ++i)
                  if (flags[i])
                     matcher->charset[i] |= (1 << z);
            }

            n = stb__add_node(matcher);
            stb__add_edge(matcher, last_end, n, -2 - z);
            last_start = last_end;
            last_end = n;
            break;
         }
      }
   }
   *end = last_end;
   return regex;
}

static char *stb__reg_parse_alt(stb_matcher *matcher, int start, char *regex, uint16 *end)
{
   uint16 last_end = start;
   uint16 main_end;

   int head, tail;

   head = stb__add_node(matcher);
   stb__add_epsilon(matcher, start, head);

   regex = stb__reg_parse(matcher, head, regex, &last_end);
   if (regex == NULL) return NULL;
   if (*regex == 0 || *regex == ')') {
      *end = last_end;
      return regex;
   }

   main_end = last_end;
   tail = stb__add_node(matcher);

   stb__add_epsilon(matcher, last_end, tail);

   // start alternatives from the same starting node; use epsilon
   // transitions to combine their endings
   while(*regex && *regex != ')') {
      assert(*regex == '|');
      head = stb__add_node(matcher);
      stb__add_epsilon(matcher, start, head);
      regex = stb__reg_parse(matcher, head, regex+1, &last_end);
      if (regex == NULL)
         return NULL;
      stb__add_epsilon(matcher, last_end, tail);
   }

   *end = tail;
   return regex;
}

static char *stb__wild_parse(stb_matcher *matcher, int start, char *str, uint16 *end)
{
   int n;
   uint16 last_end;

   last_end = stb__add_node(matcher);
   stb__add_epsilon(matcher, start, last_end);

   while (*str) {
      switch (*str) {
            // fallthrough
         default: // match exactly this character
            n = stb__add_node(matcher);
            if (toupper(*str) == tolower(*str)) {
               stb__add_edge(matcher, last_end, n, *str);
            } else {
               stb__add_edge(matcher, last_end, n, tolower(*str));
               stb__add_edge(matcher, last_end, n, toupper(*str));
            }
            last_end = n;
            ++str;
            break;

         case '?':
            n = stb__add_node(matcher);
            stb__add_edge(matcher, last_end, n, -1);
            last_end = n;
            ++str;
            break;

         case '*':
            n = stb__add_node(matcher);
            stb__add_edge(matcher, last_end, n, -1);
            stb__add_epsilon(matcher, last_end, n);
            stb__add_epsilon(matcher, n, last_end);
            last_end = n;
            ++str;
            break;
      }
   }

   // now require end of string to match
   n = stb__add_node(matcher);
   stb__add_edge(matcher, last_end, n, 0);
   last_end = n;

   *end = last_end;
   return str;
}

static int stb__opt(stb_matcher *m, int n)
{
   for(;;) {
      stb_nfa_node *p = &m->nodes[n];
      if (p->goal)                  return n;
      if (stb_arr_len(p->out))      return n;
      if (stb_arr_len(p->eps) != 1) return n;
      n = p->eps[0];
   }
}

static void stb__optimize(stb_matcher *m)
{
   // if the target of any edge is a node with exactly
   // one out-epsilon, shorten it
   int i,j;
   for (i=0; i < stb_arr_len(m->nodes); ++i) {
      stb_nfa_node *p = &m->nodes[i];
      for (j=0; j < stb_arr_len(p->out); ++j)
         p->out[j].node = stb__opt(m,p->out[j].node);
      for (j=0; j < stb_arr_len(p->eps); ++j)
         p->eps[j]      = stb__opt(m,p->eps[j]     );
   }
   m->start_node = stb__opt(m,m->start_node);
}

void stb_matcher_free(stb_matcher *f)
{
   stb_free(f);
}

static stb_matcher *stb__alloc_matcher(void)
{
   stb_matcher *matcher = (stb_matcher *) stb_malloc(0,sizeof(*matcher));

   matcher->start_node  = 0;
   stb_arr_malloc((void **) &matcher->nodes, matcher);
   matcher->num_charset = 0;
   matcher->match_start = 0;
   matcher->does_lex    = 0;

   matcher->dfa_start   = STB__DFA_UNDEF;
   stb_arr_malloc((void **) &matcher->dfa, matcher);
   stb_arr_malloc((void **) &matcher->dfa_mapping, matcher);
   stb_arr_malloc((void **) &matcher->dfa_result, matcher);

   stb__add_node(matcher);

   return matcher;
}

static void stb__lex_reset(stb_matcher *matcher)
{
   // flush cached dfa data
   stb_arr_setlen(matcher->dfa, 0);
   stb_arr_setlen(matcher->dfa_mapping, 0);
   stb_arr_setlen(matcher->dfa_result, 0);
   matcher->dfa_start = STB__DFA_UNDEF;
}

stb_matcher *stb_regex_matcher(char *regex)
{
   void *c = stb__arr_context;
   char *z;
   uint16 end;
   stb_matcher *matcher = stb__alloc_matcher();
   if (*regex == '^') {
      matcher->match_start = 1;
      ++regex;
   }

   z = stb__reg_parse_alt(matcher, matcher->start_node, regex, &end);

   if (!z || *z) {
      stb_free(matcher);
      return NULL;
   }

   ((matcher->nodes)[(int) end]).goal = STB__NFA_STOP_GOAL;

   return matcher;
}

stb_matcher *stb_lex_matcher(void)
{
   stb_matcher *matcher = stb__alloc_matcher();

   matcher->match_start = 1;
   matcher->does_lex    = 1;

   return matcher;
}

int stb_lex_item(stb_matcher *matcher, char *regex, int result)
{
   char *z;
   uint16 end;

   z = stb__reg_parse_alt(matcher, matcher->start_node, regex, &end);

   if (z == NULL)
      return 0;

   stb__lex_reset(matcher);

   matcher->nodes[(int) end].goal = result;
   return 1;
}

int stb_lex_item_wild(stb_matcher *matcher, char *regex, int result)
{
   char *z;
   uint16 end;

   z = stb__wild_parse(matcher, matcher->start_node, regex, &end);

   if (z == NULL)
      return 0;

   stb__lex_reset(matcher);

   matcher->nodes[(int) end].goal = result;
   return 1;
}

static void stb__clear(stb_matcher *m, STB__ARR(uint16) list)
{
   int i;
   for (i=0; i < stb_arr_len(list); ++i)
      m->nodes[(int) list[i]].active = 0;
}

static int stb__clear_goalcheck(stb_matcher *m, STB__ARR(uint16) list)
{
   int i, t=0;
   for (i=0; i < stb_arr_len(list); ++i) {
      t += m->nodes[(int) list[i]].goal;
      m->nodes[(int) list[i]].active = 0;
   }
   return t;
}

static uint16 * stb__add_if_inactive(stb_matcher *m, STB__ARR(uint16) list, int n)
{
   if (!m->nodes[n].active) {
      stb_arr_push(list, n);
      m->nodes[n].active = 1;
   }
   return list;
}

static uint16 * stb__eps_closure(stb_matcher *m, STB__ARR(uint16) list)
{
   int i,n = stb_arr_len(list);

   for(i=0; i < n; ++i) {
      STB__ARR(uint16) e = m->nodes[(int) list[i]].eps;
      if (e) {
         int j,k = stb_arr_len(e);
         for (j=0; j < k; ++j)
            list = stb__add_if_inactive(m, list, e[j]);
         n = stb_arr_len(list);
      }
   }

   return list;
}

int stb_matcher_match(stb_matcher *m, char *str)
{
   int result = 0;
   int i,j,y,z;
   STB__ARR(uint16) previous = NULL;
   STB__ARR(uint16) current = NULL;
   uint16 *temp;

   stb_arr_setsize(previous, 4);
   stb_arr_setsize(current, 4);

   previous = stb__add_if_inactive(m, previous, m->start_node);
   previous = stb__eps_closure(m,previous);
   stb__clear(m, previous);

   while (*str && stb_arr_len(previous)) {
      y = stb_arr_len(previous);
      for (i=0; i < y; ++i) {
         stb_nfa_node *n = &m->nodes[(int) previous[i]];
         z = stb_arr_len(n->out);
         for (j=0; j < z; ++j) {
            if (n->out[j].match >= 0) {
               if (n->out[j].match == *str)
                  current = stb__add_if_inactive(m, current, n->out[j].node);
            } else if (n->out[j].match == -1) {
               if (*str != '\n')
                  current = stb__add_if_inactive(m, current, n->out[j].node);
            } else if (n->out[j].match < -1) {
               int z = -n->out[j].match - 2;
               if (m->charset[(uint8) *str] & (1 << z))
                  current = stb__add_if_inactive(m, current, n->out[j].node);
            }
         }
      }
      stb_arr_setlen(previous, 0);

      temp = previous;
      previous = current;
      current = temp;

      previous = stb__eps_closure(m,previous);
      stb__clear(m, previous);

      ++str;
   }

   // transition to pick up a '$' at the end
   y = stb_arr_len(previous);
   for (i=0; i < y; ++i)
      m->nodes[(int) previous[i]].active = 1;

   for (i=0; i < y; ++i) {
      stb_nfa_node *n = &m->nodes[(int) previous[i]];
      z = stb_arr_len(n->out);
      for (j=0; j < z; ++j) {
         if (n->out[j].match == '\n')
            current = stb__add_if_inactive(m, current, n->out[j].node);
      }
   }

   previous = stb__eps_closure(m,previous);
   stb__clear(m, previous);

   y = stb_arr_len(previous);
   for (i=0; i < y; ++i)
      if (m->nodes[(int) previous[i]].goal)
         result = 1;

   stb_arr_free(previous);
   stb_arr_free(current);

   return result && *str == 0;
}

int16 stb__get_dfa_node(stb_matcher *m, STB__ARR(uint16) list)
{
   uint16 node;
   uint32 data[8], *state, *newstate;
   int i,j,n;

   state = (uint32 *) stb_temp(data, m->num_words_per_dfa * 4);
   memset(state, 0, m->num_words_per_dfa*4);

   n = stb_arr_len(list);
   for (i=0; i < n; ++i) {
      int x = list[i];
      state[x >> 5] |= 1 << (x & 31);
   }

   // @TODO use a hash table
   n = stb_arr_len(m->dfa_mapping);
   i=j=0;
   for(; j < n; ++i, j += m->num_words_per_dfa) {
      // @TODO special case for <= 32
      if (!memcmp(state, m->dfa_mapping + j, m->num_words_per_dfa*4)) {
         node = i;
         goto done;
      }
   }

   assert(stb_arr_len(m->dfa) == i);
   node = i;

   newstate = stb_arr_addn(m->dfa_mapping, m->num_words_per_dfa);
   memcpy(newstate, state, m->num_words_per_dfa*4);

   // set all transitions to 'unknown'
   stb_arr_add(m->dfa);
   memset(m->dfa[i].transition, -1, sizeof(m->dfa[i].transition));

   if (m->does_lex) {
      int result = -1;
      n = stb_arr_len(list);
      for (i=0; i < n; ++i) {
         if (m->nodes[(int) list[i]].goal > result)
            result = m->nodes[(int) list[i]].goal;
      }

      stb_arr_push(m->dfa_result, result);
   }

done:
   stb_tempfree(data, state);
   return node;
}

static int stb__matcher_dfa(stb_matcher *m, char *str_c, int *len)
{
   stb_uint8 *str = (stb_uint8 *) str_c;
   int16 node,prevnode;
   stb_dfa *trans;
   int match_length = 0;
   stb_int16 match_result=0;

   if (m->dfa_start == STB__DFA_UNDEF) {
      STB__ARR(stb_uint16) list;

      m->num_words_per_dfa = (stb_arr_len(m->nodes)+31) >> 5;
      stb__optimize(m);

      list = stb__add_if_inactive(m, NULL, m->start_node);
      list = stb__eps_closure(m,list);
      if (m->does_lex) {
         m->dfa_start = stb__get_dfa_node(m,list);
         stb__clear(m, list);
         // DON'T allow start state to be a goal state!
         // this allows people to specify regexes that can match 0
         // characters without them actually matching (also we don't
         // check _before_ advancing anyway
         if (m->dfa_start <= STB__DFA_MGOAL)
            m->dfa_start = -(m->dfa_start - STB__DFA_MGOAL);
      } else {
         if (stb__clear_goalcheck(m, list))
            m->dfa_start = STB__DFA_GOAL;
         else
            m->dfa_start = stb__get_dfa_node(m,list);
      }
      stb_arr_free(list);
   }

   prevnode = STB__DFA_UNDEF;
   node = m->dfa_start;
   trans = m->dfa;

   if (m->dfa_start == STB__DFA_GOAL)
      return 1;

   for(;;) {
      assert(node >= STB__DFA_VALID);

      // fast inner DFA loop; especially if STB__DFA_VALID is 0

      do {
         prevnode = node;
         node = trans[node].transition[*str++];
      } while (node >= STB__DFA_VALID);

      assert(node >= STB__DFA_MGOAL - stb_arr_len(m->dfa));
      assert(node < stb_arr_len(m->dfa));

      // special case for lex: need _longest_ match, so notice goal
      // state without stopping
      if (node <= STB__DFA_MGOAL) {
         match_length = str - (stb_uint8 *) str_c;
         node = -(node - STB__DFA_MGOAL);
         match_result = node;
         continue;
      }

      // slow NFA->DFA conversion

      // or we hit the goal or the end of the string, but those
      // can only happen once per search...

      if (node == STB__DFA_UNDEF) {
         // build a list  -- @TODO special case <= 32 states
         // heck, use a more compact data structure for <= 16 and <= 8 ?!

         // @TODO keep states/newstates around instead of reallocating them
         STB__ARR(uint16) states = NULL;
         STB__ARR(uint16) newstates = NULL;
         int i,j,y,z;
         uint32 *flags = &m->dfa_mapping[prevnode * m->num_words_per_dfa];
         assert(prevnode != STB__DFA_UNDEF);
         stb_arr_setsize(states, 4);
         stb_arr_setsize(newstates,4);
         for (j=0; j < m->num_words_per_dfa; ++j) {
            for (i=0; i < 32; ++i) {
               if (*flags & (1 << i))
                  stb_arr_push(states, j*32+i);
            }
            ++flags;
         }
         // states is now the states we were in in the previous node;
         // so now we can compute what node it transitions to on str[-1]

         y = stb_arr_len(states);
         for (i=0; i < y; ++i) {
            stb_nfa_node *n = &m->nodes[(int) states[i]];
            z = stb_arr_len(n->out);
            for (j=0; j < z; ++j) {
               if (n->out[j].match >= 0) {
                  if (n->out[j].match == str[-1] || (str[-1] == 0 && n->out[j].match == '\n'))
                     newstates = stb__add_if_inactive(m, newstates, n->out[j].node);
               } else if (n->out[j].match == -1) {
                  if (str[-1] != '\n' && str[-1])
                     newstates = stb__add_if_inactive(m, newstates, n->out[j].node);
               } else if (n->out[j].match < -1) {
                  int z = -n->out[j].match - 2;
                  if (m->charset[str[-1]] & (1 << z))
                     newstates = stb__add_if_inactive(m, newstates, n->out[j].node);
               }
            }
         }
         // AND add in the start state!
         if (!m->match_start || (str[-1] == '\n' && !m->does_lex))
            newstates = stb__add_if_inactive(m, newstates, m->start_node);
         // AND epsilon close it
         newstates = stb__eps_closure(m, newstates);
         // if it's a goal state, then that's all there is to it
         if (stb__clear_goalcheck(m, newstates)) {
            if (m->does_lex) {
               match_length = str - (stb_uint8 *) str_c;
               node = stb__get_dfa_node(m,newstates);
               match_result = node;
               node = -node + STB__DFA_MGOAL;
               trans = m->dfa; // could have gotten realloc()ed
            } else
               node = STB__DFA_GOAL;
         } else if (str[-1] == 0 || stb_arr_len(newstates) == 0) {
            node = STB__DFA_END;
         } else {
            node = stb__get_dfa_node(m,newstates);
            trans = m->dfa; // could have gotten realloc()ed
         }
         trans[prevnode].transition[str[-1]] = node;
         if (node <= STB__DFA_MGOAL)
            node = -(node - STB__DFA_MGOAL);
         stb_arr_free(newstates);
         stb_arr_free(states);
      }

      if (node == STB__DFA_GOAL) {
         return 1;
      }
      if (node == STB__DFA_END) {
         if (m->does_lex) {
            if (match_result) {
               if (len) *len = match_length;
               return m->dfa_result[(int) match_result];
            }
         }
         return 0;
      }

      assert(node != STB__DFA_UNDEF);
   }
}

int stb_matcher_find(stb_matcher *m, char *str)
{
   assert(m->does_lex == 0);
   return stb__matcher_dfa(m, str, NULL);
}

int stb_lex(stb_matcher *m, char *str, int *len)
{
   assert(m->does_lex);
   return stb__matcher_dfa(m, str, len);
}

int stb_regex(char *regex, char *str)
{
   static stb_perfect p;
   static STB__ARR(stb_matcher *) matchers;
   static STB__ARR(char        *) regexps;
   static STB__ARR(char        *) regexp_cache;
   static unsigned short *mapping;
   int z = stb_perfect_hash(&p, (int) regex);
   if (z >= 0) {
      if (strcmp(regex, regexp_cache[(int) mapping[z]])) {
         int i = mapping[z];
         stb_matcher_free(matchers[i]);
         free(regexp_cache[i]);
         regexps[i] = regex;
         regexp_cache[i] = strdup(regex);
         matchers[i] = stb_regex_matcher(regex);
      }
   } else {
      int i,n;
      if (regex == NULL) {
         for (i=0; i < stb_arr_len(matchers); ++i) {
            stb_matcher_free(matchers[i]);
            free(regexp_cache[i]);
         }
         matchers = stb_arr_free(matchers);
         regexps = stb_arr_free(regexps);
         regexp_cache = stb_arr_free(regexp_cache);
         stb_perfect_destroy(&p);
         free(mapping); mapping = NULL;
         return -1;
      }
      stb_arr_push(regexps, regex);
      stb_arr_push(regexp_cache, strdup(regex));
      stb_arr_push(matchers, stb_regex_matcher(regex));
      stb_perfect_destroy(&p);
      n = stb_perfect_create(&p, (unsigned int *) (char **) regexps, stb_arr_len(regexps));
      mapping = (unsigned short *) realloc(mapping, n * sizeof(*mapping));
      for (i=0; i < stb_arr_len(regexps); ++i)
         mapping[stb_perfect_hash(&p, (int) regexps[i])] = i;
      z = stb_perfect_hash(&p, (int) regex);
   }
   return stb_matcher_find(matchers[(int) mapping[z]], str);
}

#endif // STB_DEFINE


#if 0
//////////////////////////////////////////////////////////////////////////////
//
//                      C source-code introspection
//

typedef struct
{
   char *name;
   char *type;
   char *comment;
   int   size;
   int   offset;
   int   arrcount[2];
} stb_info_field;

typedef struct
{
   char *structname;
   int size;
   int num_fields;
   stb_info_field *fields;
} stb_info_struct;

extern stb_info_struct stb__introspect_output[];

STB_EXTERN void stb_introspect_precompiled(stb_info_struct *compiled);
STB_EXTERN void stb__introspect(char *path, char *file);

#define stb_introspect_ship()            stb__introspect(NULL, NULL, stb__introspect_output)

#ifdef STB_SHIP
#define stb_introspect()                 stb_introspect_ship()
#define stb_introspect_path(p)           stb_introspect_ship()
#else
// bootstrapping: define stb_introspect() (or 'path') the first time
#define stb_introspect()                 stb__introspect(NULL, __FILE__, NULL)
#define stb_introspect_auto()            stb__introspect(NULL, __FILE__, stb__introspect_output)

#define stb_introspect_path(p)           stb__introspect(p, __FILE__, NULL)
#define stb_introspect_path(p)           stb__introspect(p, __FILE__, NULL)
#endif

#ifdef STB_DEFINE

#ifndef STB_INTROSPECT_CPP
   #ifdef __cplusplus
   #define STB_INTROSPECT_CPP 1
   #else
   #define STB_INTROSPECT_CPP 0
   #endif
#endif

void stb_introspect_precompiled(stb_info_struct *compiled)
{

}


static void stb__introspect_filename(char *buffer, char *path)
{
   #if STB_INTROSPECT_CPP
   sprintf(buffer, "%s/stb_introspect.cpp", path);
   #else
   sprintf(buffer, "%s/stb_introspect.c", path);
   #endif
}

static void stb__introspect_compute(char *path, char *file)
{
   int i;
   STB__ARR(char *) include_list = NULL;
   STB__ARR(char *) introspect_list = NULL;
   FILE *f;
   f = fopen(file, "w");
   if (!f) return;

   fputs("// if you get compiler errors, change the following 0 to a 1:\n", f);
   fputs("#define STB_INTROSPECT_INVALID 0\n\n", f);
   fputs("// this will force the code to compile, and force the introspector\n", f);
   fputs("// to run and then exit, allowing you to recompile\n\n\n", f);
   fputs("#include \"stb.h\"\n\n",f );
   fputs("#if STB_INTROSPECT_INVALID\n", f);
   fputs("   stb_info_struct stb__introspect_output[] = { (void *) 1 }\n", f);
   fputs("#else\n\n", f);
   for (i=0; i < stb_arr_len(include_list); ++i)
      fprintf(f, " #include \"%s\"\n", include_list[i]);

   fputs(" stb_info_struct stb__introspect_output[] =\n{\n", f);
   for (i=0; i < stb_arr_len(introspect_list); ++i)
      fprintf(f, "  stb_introspect_%s,\n", introspect_list[i]);
   fputs(" };\n", f);
   fputs("#endif\n", f);
   fclose(f);
}

static stb_info_struct *stb__introspect_info;

#ifndef STB_SHIP

#endif

void stb__introspect(char *path, char *file, stb_info_struct *compiled)
{
   static int first=1;
   if (!first) return;
   first=0;

   stb__introspect_info = compiled;

   #ifndef STB_SHIP
   if (path || file) {
      int bail_flag = compiled && compiled[0].structname == (void *) 1;
      int needs_building = bail_flag;
      struct stb__stat st;
      char buffer[1024], buffer2[1024];
      if (!path) {
         stb_splitpath(buffer, file, STB_PATH);
         path = buffer;
      }
      // bail if the source path doesn't exist
      if (!stb_fexists(path)) return;

      stb__introspect_filename(buffer2, path);

      // get source/include files timestamps, compare to output-file timestamp;
      // if mismatched, regenerate 

      if (stb__stat(buffer2, &st))
         needs_building = TRUE;
      
      {
         // find any file that contains an introspection command and is newer
         // if needs_building is already true, we don't need to do this test,
         // but we still need these arrays, so go ahead and get them
         STB__ARR(char *) all[3];
         all[0] = stb_readdir_files_mask(path, "*.h");
         all[1] = stb_readdir_files_mask(path, "*.c");
         all[2] = stb_readdir_files_mask(path, "*.cpp");
         int i,j;
         if (needs_building) {
            for (j=0; j < 3; ++j) {
               for (i=0; i < stb_arr_len(all[j]); ++i) {
                  struct stb__stat st2;
                  if (!stb__stat(all[j][i], &st2)) {
                     if (st.st_mtime < st2.st_mtime) {
                        char *z = stb_filec(all[j][i], NULL);
                        int found=FALSE;
                        while (y) {
                           y = strstr(y, "//si");
                           if (y && isspace(y[4])) {
                              found = TRUE;
                              break;
                           }
                        }
                        needs_building = TRUE;
                        goto done;
                     }
                  }
               }
            }
           done:;
         }
               char *z = stb_filec(all[i], NULL), *y = z;
               int found=FALSE;
               while (y) {
                  y = strstr(y, "//si");
                  if (y && isspace(y[4])) {
                     found = TRUE;
                     break;
                  }
               }
               if (found)
                  stb_arr_push(introspect_h, strdup(all[i]));
               free(z);
            }
         }
         stb_readdir_free(all);
         if (!needs_building) {
            for (i=0; i < stb_arr_len(introspect_h); ++i) {
               struct stb__stat st2;
               if (!stb__stat(introspect_h[i], &st2))
                  if (st.st_mtime < st2.st_mtime)
                     needs_building = TRUE;
            }
         }

         if (needs_building) {
            stb__introspect_compute(path, buffer2);
         }
      }
   }
   #endif
}
#endif
#endif

//////////////////////////////////////////////////////////////////////////////
//
//             STB-C sliding-window dictionary compression
//
//  This uses a DEFLATE-style sliding window, but no bitwise entropy.
//  Everything is on byte boundaries, so you could then apply a byte-wise
//  entropy code, though that's nowhere near as effective.
//
//  An STB-C stream begins with a 16-byte header:
//      4 bytes: 0x57 0xBC 0x00 0x00
//      8 bytes: big-endian size of decompressed data, 64-bits
//      4 bytes: big-endian size of window (how far back decompressor may need)
//
//  The following symbols appear in the stream (these were determined ad hoc,
//  not by analysis):
//
//  [dict]      00000100 yyyyyyyy yyyyyyyy yyyyyyyy xxxxxxxx xxxxxxxx
//  [END]       00000101 11111010 cccccccc cccccccc cccccccc cccccccc
//  [dict]      00000110 yyyyyyyy yyyyyyyy yyyyyyyy xxxxxxxx
//  [literals]  00000111 zzzzzzzz zzzzzzzz
//  [literals]  00001zzz zzzzzzzz
//  [dict]      00010yyy yyyyyyyy yyyyyyyy xxxxxxxx xxxxxxxx
//  [dict]      00011yyy yyyyyyyy yyyyyyyy xxxxxxxx
//  [literals]  001zzzzz
//  [dict]      01yyyyyy yyyyyyyy xxxxxxxx
//  [dict]      1xxxxxxx yyyyyyyy
//
//      xxxxxxxx: match length - 1
//      yyyyyyyy: backwards distance - 1
//      zzzzzzzz: num literals - 1
//      cccccccc: adler32 checksum of decompressed data
//   (all big-endian)


STB_EXTERN stb_uint stb_decompress_length(stb_uchar *input);
STB_EXTERN stb_uint stb_decompress(stb_uchar *out,stb_uchar *in,stb_uint len);
STB_EXTERN stb_uint stb_compress  (stb_uchar *out,stb_uchar *in,stb_uint len);
STB_EXTERN void stb_compress_window(int z);
STB_EXTERN void stb_compress_hashsize(unsigned int z);

STB_EXTERN int stb_compress_tofile(char *filename, char *in,  stb_uint  len);
STB_EXTERN int stb_compress_intofile(FILE *f, char *input,    stb_uint  len);
STB_EXTERN char *stb_decompress_fromfile(char *filename,      stb_uint *len);

STB_EXTERN int stb_compress_stream_start(FILE *f);
STB_EXTERN void stb_compress_stream_end(int close);
STB_EXTERN void stb_write(char *data, int data_len);

#ifdef STB_DEFINE

stb_uint stb_decompress_length(stb_uchar *input)
{
   return (input[8] << 24) + (input[9] << 16) + (input[10] << 8) + input[11];
}

////////////////////           decompressor         ///////////////////////

// simple implementation that just writes whole thing into big block

static unsigned char *stb__barrier;
static unsigned char *stb__barrier2;
static unsigned char *stb__barrier3;
static unsigned char *stb__barrier4;

static stb_uchar *stb__dout;
static void stb__match(stb_uchar *data, stb_uint length)
{
   // INVERSE of memmove... write each byte before copying the next...
   assert (stb__dout + length <= stb__barrier);
   if (stb__dout + length > stb__barrier) { stb__dout += length; return; }
   if (data < stb__barrier4) { stb__dout = stb__barrier+1; return; }
   while (length--) *stb__dout++ = *data++;
}

static void stb__lit(stb_uchar *data, stb_uint length)
{
   assert (stb__dout + length <= stb__barrier);
   if (stb__dout + length > stb__barrier) { stb__dout += length; return; }
   if (data < stb__barrier2) { stb__dout = stb__barrier+1; return; }
   memcpy(stb__dout, data, length);
   stb__dout += length;
}

#define stb__in2(x)   ((i[x] << 8) + i[(x)+1])
#define stb__in3(x)   ((i[x] << 16) + stb__in2((x)+1))
#define stb__in4(x)   ((i[x] << 24) + stb__in3((x)+1))

static stb_uchar *stb_decompress_token(stb_uchar *i)
{
   if (*i >= 0x20) { // use fewer if's for cases that expand small
      if (*i >= 0x80)       stb__match(stb__dout-i[1]-1, i[0] - 0x80 + 1), i += 2;
      else if (*i >= 0x40)  stb__match(stb__dout-(stb__in2(0) - 0x4000 + 1), i[2]+1), i += 3;
      else /* *i >= 0x20 */ stb__lit(i+1, i[0] - 0x20 + 1), i += 1 + (i[0] - 0x20 + 1);
   } else { // more ifs for cases that expand large, since overhead is amortized
      if (*i >= 0x18)       stb__match(stb__dout-(stb__in3(0) - 0x180000 + 1), i[3]+1), i += 4;
      else if (*i >= 0x10)  stb__match(stb__dout-(stb__in3(0) - 0x100000 + 1), stb__in2(3)+1), i += 5;
      else if (*i >= 0x08)  stb__lit(i+2, stb__in2(0) - 0x0800 + 1), i += 2 + (stb__in2(0) - 0x0800 + 1);
      else if (*i == 0x07)  stb__lit(i+3, stb__in2(1) + 1), i += 3 + (stb__in2(1) + 1);
      else if (*i == 0x06)  stb__match(stb__dout-(stb__in3(1)+1), i[4]+1), i += 5;
      else if (*i == 0x04)  stb__match(stb__dout-(stb__in3(1)+1), stb__in2(4)+1), i += 6;
   }
   return i;
}

stb_uint stb_decompress(stb_uchar *output, stb_uchar *i, stb_uint length)
{
   stb_uint olen;
   if (stb__in4(0) != 0x57bC0000) return 0;
   if (stb__in4(4) != 0)          return 0; // error! stream is > 4GB
   olen = stb_decompress_length(i);
   stb__barrier2 = i;
   stb__barrier3 = i+length;
   stb__barrier = output + olen;
   stb__barrier4 = output;
   i += 16;

   stb__dout = output;
   while (1) {
      stb_uchar *old_i = i;
      i = stb_decompress_token(i);
      if (i == old_i) {
         if (*i == 0x05 && i[1] == 0xfa) {
            assert(stb__dout == output + olen);
            if (stb__dout != output + olen) return 0;
            if (stb_adler32(1, output, olen) != (stb_uint) stb__in4(2))
               return 0;
            return olen;
         } else {
            assert(0); /* NOTREACHED */
            return 0;
         }
      }
      assert(stb__dout <= output + olen); 
      if (stb__dout > output + olen)
         return 0;
   }
}

char *stb_decompress_fromfile(char *filename, unsigned int *len)
{
   unsigned int n;
   char *q;
   unsigned char *p;
   FILE *f = fopen(filename, "rb");   if (f == NULL) return NULL;
   fseek(f, 0, SEEK_END);
   n = ftell(f);
   fseek(f, 0, SEEK_SET);
   p = (unsigned char * ) malloc(n); if (p == NULL) return NULL;
   fread(p, 1, n, f);
   fclose(f);
   if (p == NULL) return NULL;
   if (p[0] != 0x57 || p[1] != 0xBc || p[2] || p[3]) { free(p); return NULL; }
   q = (char *) malloc(stb_decompress_length(p)+1);
   if (!q) { free(p); free(p); return NULL; }
   *len = stb_decompress((unsigned char *) q, p, n);
   if (*len) q[*len] = 0;
   free(p);
   return q;
}

#if 0
//  streaming decompressor

static struct
{
   stb__uchar *in_buffer;
   stb__uchar *match;

   stb__uint pending_literals;
   stb__uint pending_match;
} xx;



static void stb__match(stb_uchar *data, stb_uint length)
{
   // INVERSE of memmove... write each byte before copying the next...
   assert (stb__dout + length <= stb__barrier);
   if (stb__dout + length > stb__barrier) { stb__dout += length; return; }
   if (data < stb__barrier2) { stb__dout = stb__barrier+1; return; }
   while (length--) *stb__dout++ = *data++;
}

static void stb__lit(stb_uchar *data, stb_uint length)
{
   assert (stb__dout + length <= stb__barrier);
   if (stb__dout + length > stb__barrier) { stb__dout += length; return; }
   if (data < stb__barrier2) { stb__dout = stb__barrier+1; return; }
   memcpy(stb__dout, data, length);
   stb__dout += length;
}

static void sx_match(stb_uchar *data, stb_uint length)
{
   xx.match = data;
   xx.pending_match = length;
}

static void sx_lit(stb_uchar *data, stb_uint length)
{
   xx.pending_lit = length;
}

static int stb_decompress_token_state(void)
{
   stb__uchar *i = xx.in_buffer;

   if (*i >= 0x20) { // use fewer if's for cases that expand small
      if (*i >= 0x80)       sx_match(stb__dout-i[1]-1, i[0] - 0x80 + 1), i += 2;
      else if (*i >= 0x40)  sx_match(stb__dout-(stb__in2(0) - 0x4000 + 1), i[2]+1), i += 3;
      else /* *i >= 0x20 */ sx_lit(i+1, i[0] - 0x20 + 1), i += 1;
   } else { // more ifs for cases that expand large, since overhead is amortized
      if (*i >= 0x18)       sx_match(stb__dout-(stb__in3(0) - 0x180000 + 1), i[3]+1), i += 4;
      else if (*i >= 0x10)  sx_match(stb__dout-(stb__in3(0) - 0x100000 + 1), stb__in2(3)+1), i += 5;
      else if (*i >= 0x08)  sx_lit(i+2, stb__in2(0) - 0x0800 + 1), i += 2;
      else if (*i == 0x07)  sx_lit(i+3, stb__in2(1) + 1), i += 3;
      else if (*i == 0x06)  sx_match(stb__dout-(stb__in3(1)+1), i[4]+1), i += 5;
      else if (*i == 0x04)  sx_match(stb__dout-(stb__in3(1)+1), stb__in2(4)+1), i += 6;
      else return 0;
   }
   xx.in_buffer = i;
   return 1;
}
#endif



////////////////////           compressor         ///////////////////////

static unsigned int stb_matchlen(stb_uchar *m1, stb_uchar *m2, stb_uint maxlen)
{
   stb_uint i;
   for (i=0; i < maxlen; ++i)
      if (m1[i] != m2[i]) return i;
   return i;
}

// simple implementation that just takes the source data in a big block

static stb_uchar *stb__out;
static FILE      *stb__outfile;
static stb_uint   stb__outbytes;

static void stb__write(unsigned char v)
{
   fputc(v, stb__outfile);
   ++stb__outbytes;
}

#define stb_out(v)    (stb__out ? *stb__out++ = (stb_uchar) (v) : stb__write((stb_uchar) (v)))

static void stb_out2(stb_uint v)
{
   stb_out(v >> 8);
   stb_out(v);
}

static void stb_out3(stb_uint v) { stb_out(v >> 16); stb_out(v >> 8); stb_out(v); }
static void stb_out4(stb_uint v) { stb_out(v >> 24); stb_out(v >> 16);
                                   stb_out(v >> 8 ); stb_out(v);                  }

static void outliterals(stb_uchar *in, int numlit)
{
   while (numlit > 65536) {
      outliterals(in,65536);
      in     += 65536;
      numlit -= 65536;
   }

   if      (numlit ==     0)    ;
   else if (numlit <=    32)    stb_out (0x000020 + numlit-1);
   else if (numlit <=  2048)    stb_out2(0x000800 + numlit-1);
   else /*  numlit <= 65536) */ stb_out3(0x070000 + numlit-1);

   if (stb__out) {
      memcpy(stb__out,in,numlit);
      stb__out += numlit;
   } else
      fwrite(in, 1, numlit, stb__outfile);
}

static int stb__window = 0x40000; // 256K
void stb_compress_window(int z)
{
   if (z >= 0x1000000) z = 0x1000000; // limit of implementation
   if (z <      0x100) z = 0x100;   // insanely small
   stb__window = z;
}

static int stb_not_crap(int best, int dist)
{
   return   ((best > 2  &&  dist <= 0x00100)     
          || (best > 5  &&  dist <= 0x04000)
          || (best > 7  &&  dist <= 0x80000));
}

static  stb_uint stb__hashsize = 32768;
void stb_compress_hashsize(unsigned int y)
{
   unsigned int z = 1024;
   while (z < y) z <<= 1;
   stb__hashsize = z >> 2;   // pass in bytes, store #pointers
}

// note that you can play with the hashing functions all you
// want without needing to change the decompressor
#define stb__hc(q,h,c)      (((h) << 7) + ((h) >> 25) + q[c])
#define stb__hc2(q,h,c,d)   (((h) << 14) + ((h) >> 18) + (q[c] << 7) + q[d])
#define stb__hc3(q,c,d,e)   ((q[c] << 14) + (q[d] << 7) + q[e])

static stb_uint32 stb__running_adler;

static int stb_compress_chunk(stb_uchar *history,
                              stb_uchar *start,
                              stb_uchar *end,
                              int length,
                              int *pending_literals,
                              stb_uchar **chash,
                              stb_uint mask)
{
   int window = stb__window;
   stb_uint match_max;
   stb_uchar *lit_start = start - *pending_literals;
   stb_uchar *q = start;

   #define STB__SCRAMBLE(h)   (((h) + ((h) >> 16)) & mask)

   // stop short of the end so we don't scan off the end doing
   // the hashing; this means we won't compress the last few bytes
   // unless they were part of something longer
   while (q < start+length && q+12 < end) {
      int m;
      stb_uint h1,h2,h3,h4, h;
      stb_uchar *t;
      int best = 2, dist=0;

      if (q+65536 > end)
         match_max = end-q;
      else
         match_max = 65536;

      #define stb__nc(b,d)  ((d) <= window && ((b) > 9 || stb_not_crap(b,d)))

      #define STB__TRY(t,p)  /* avoid retrying a match we already tried */ \
                      if (p ? dist != q-t : 1)                             \
                      if ((m = stb_matchlen(t, q, match_max)) > best)     \
                      if (stb__nc(m,q-(t)))                                \
                          best = m, dist = q - (t)

      // rather than search for all matches, only try 4 candidate locations,
      // chosen based on 4 different hash functions of different lengths.
      // this strategy is inspired by LZO; hashing is unrolled here using the
      // 'hc' macro
      h = stb__hc3(q,0, 1, 2); h1 = STB__SCRAMBLE(h);
                                      t = chash[h1]; if (t) STB__TRY(t,0);
      h = stb__hc2(q,h, 3, 4); h2 = STB__SCRAMBLE(h);
      h = stb__hc2(q,h, 5, 6);        t = chash[h2]; if (t) STB__TRY(t,1);
      h = stb__hc2(q,h, 7, 8); h3 = STB__SCRAMBLE(h);
      h = stb__hc2(q,h, 9,10);        t = chash[h3]; if (t) STB__TRY(t,1);
      h = stb__hc2(q,h,11,12); h4 = STB__SCRAMBLE(h);
                                      t = chash[h4]; if (t) STB__TRY(t,1);

      // because we use a shared hash table, can only update it
      // _after_ we've probed all of them
      chash[h1] = chash[h2] = chash[h3] = chash[h4] = q;

      if (best > 2)
         assert(dist > 0);

      // see if our best match qualifies
      if (best < 3) { // fast path literals
         ++q;
      } else if (best > 2  &&  best <= 0x80    &&  dist <= 0x100) {
         outliterals(lit_start, q-lit_start); lit_start = (q += best);
         stb_out(0x80 + best-1);
         stb_out(dist-1);
      } else if (best > 5  &&  best <= 0x100   &&  dist <= 0x4000) {
         outliterals(lit_start, q-lit_start); lit_start = (q += best);
         stb_out2(0x4000 + dist-1);       
         stb_out(best-1);
      } else if (best > 7  &&  best <= 0x100   &&  dist <= 0x80000) {
         outliterals(lit_start, q-lit_start); lit_start = (q += best);
         stb_out3(0x180000 + dist-1);     
         stb_out(best-1);
      } else if (best > 8  &&  best <= 0x10000 &&  dist <= 0x80000) {
         outliterals(lit_start, q-lit_start); lit_start = (q += best);
         stb_out3(0x100000 + dist-1);     
         stb_out2(best-1);
      } else if (best > 9                      &&  dist <= 0x1000000) {
         outliterals(lit_start, q-lit_start); lit_start = (q += best);
         if (best <= 0x100) {
            stb_out(0x06);
            stb_out3(dist-1);
            stb_out(best-1);
         } else {
            stb_out(0x04);
            stb_out3(dist-1);
            stb_out2(best-1);
         }
      } else {  // fallback literals if no match was a balanced tradeoff
         ++q;
      }
   }

   // if we didn't get all the way, add the rest to literals
   if (q-start < length)
      q = start+length;

   // the literals are everything from lit_start to q
   *pending_literals = (q - lit_start);

   stb__running_adler = stb_adler32(stb__running_adler, start, q - start);
   return q - start;
}

static int stb_compress_inner(stb_uchar *input, stb_uint length)
{
   int literals = 0;
   stb_uint len,i;

   stb_uchar **chash;
   chash = (stb_uchar**) malloc(stb__hashsize * sizeof(stb_uchar*));
   if (chash == NULL) return 0; // failure
   for (i=0; i < stb__hashsize; ++i)
      chash[i] = NULL;

   // stream signature
   stb_out(0x57); stb_out(0xbc);
   stb_out2(0);

   stb_out4(0);       // 64-bit length requires 32-bit leading 0
   stb_out4(length);
   stb_out4(stb__window);

   stb__running_adler = 1;

   len = stb_compress_chunk(input, input, input+length, length, &literals, chash, stb__hashsize-1);
   assert(len == length);

   outliterals(input+length - literals, literals);

   free(chash);

   stb_out2(0x05fa); // end opcode

   stb_out4(stb__running_adler);

   return 1; // success
}

stb_uint stb_compress(stb_uchar *out, stb_uchar *input, stb_uint length)
{
   stb__out = out;
   stb__outfile = NULL;

   stb_compress_inner(input, length);

   return stb__out - out;
}

int stb_compress_tofile(char *filename, char *input, unsigned int length)
{
   int maxlen = length + 512 + (length >> 2); // total guess
   char *buffer = (char *) malloc(maxlen);
   int blen = stb_compress((stb_uchar*)buffer, (stb_uchar*)input, length);
   
   stb__out = NULL;
   stb__outfile = fopen(filename, "wb");
   if (!stb__outfile) return 0;

   stb__outbytes = 0;

   if (!stb_compress_inner((stb_uchar*)input, length))
      return 0;

   fclose(stb__outfile);

   return stb__outbytes;
}

int stb_compress_intofile(FILE *f, char *input, unsigned int length)
{
   int maxlen = length + 512 + (length >> 2); // total guess
   //char *buffer = (char*)malloc(maxlen);
   //int blen = stb_compress((stb_uchar*)buffer, (stb_uchar*)input, length);
   
   stb__out = NULL;
   stb__outfile = f;
   if (!stb__outfile) return 0;

   stb__outbytes = 0;

   if (!stb_compress_inner((stb_uchar*)input, length))
      return 0;

   return stb__outbytes;
}

//////////////////////    streaming I/O version    /////////////////////


static stb_uint stb_out_backpatch_id(void)
{
   if (stb__out)
      return (stb_uint) stb__out;
   else
      return ftell(stb__outfile);
}

static void stb_out_backpatch(stb_uint id, stb_uint value)
{
   stb_uchar data[4] = { value >> 24, value >> 16, value >> 8, value };
   if (stb__out) {
      memcpy((void *) id, data, 4);
   } else {
      stb_uint where = ftell(stb__outfile);
      fseek(stb__outfile, id, SEEK_SET);
      fwrite(data, 4, 1, stb__outfile);
      fseek(stb__outfile, where, SEEK_SET);
   }
}

// ok, the wraparound buffer was a total failure. let's instead
// use a copying-in-place buffer, which lets us share the code.
// This is way less efficient but it'll do for now.

static struct
{
   stb_uchar *buffer;
   int size;           // physical size of buffer in bytes

   int valid;          // amount of valid data in bytes
   int start;          // bytes of data already output

   int window;
   int fsize;

   int pending_literals; // bytes not-quite output but counted in start
   int length_id;

   stb_uint total_bytes;

   stb_uchar **chash;
   stb_uint    hashmask;
} xtb;

static int stb_compress_streaming_start(void)
{
   stb_uint i;
   xtb.size = stb__window * 3;
   xtb.buffer = (stb_uchar*)malloc(xtb.size);
   if (!xtb.buffer) return 0;

   xtb.chash = (stb_uchar**)malloc(sizeof(*xtb.chash) * stb__hashsize);
   if (!xtb.chash) {
      free(xtb.buffer);
      return 0;
   }

   for (i=0; i < stb__hashsize; ++i)
      xtb.chash[i] = NULL;

   xtb.hashmask = stb__hashsize-1;

   xtb.valid        = 0;
   xtb.start        = 0;
   xtb.window       = stb__window;
   xtb.fsize        = stb__window;
   xtb.pending_literals = 0;
   xtb.total_bytes  = 0;

      // stream signature
   stb_out(0x57); stb_out(0xbc); stb_out2(0);

   stb_out4(0);       // 64-bit length requires 32-bit leading 0

   xtb.length_id = stb_out_backpatch_id();
   stb_out4(0);       // we don't know the output length yet

   stb_out4(stb__window);

   stb__running_adler = 1;

   return 1;
}

static int stb_compress_streaming_end(void)
{
   // flush out any remaining data
   stb_compress_chunk(xtb.buffer, xtb.buffer+xtb.start, xtb.buffer+xtb.valid,
                      xtb.valid-xtb.start, &xtb.pending_literals, xtb.chash, xtb.hashmask);

   // write out pending literals
   outliterals(xtb.buffer + xtb.valid - xtb.pending_literals, xtb.pending_literals);

   stb_out2(0x05fa); // end opcode
   stb_out4(stb__running_adler);

   stb_out_backpatch(xtb.length_id, xtb.total_bytes);

   free(xtb.buffer);
   free(xtb.chash);
   return 1;
}

void stb_write(char *data, int data_len)
{
   stb_uint i;

   // @TODO: fast path for filling the buffer and doing nothing else
   //   if (xtb.valid + data_len < xtb.size)

   xtb.total_bytes += data_len;

   while (data_len) {
      // fill buffer
      if (xtb.valid < xtb.size) {
         int amt = xtb.size - xtb.valid;
         if (data_len < amt) amt = data_len;
         memcpy(xtb.buffer + xtb.valid, data, amt);
         data_len -= amt;
         data     += amt;
         xtb.valid += amt;
      }
      if (xtb.valid < xtb.size)
         return;

      // at this point, the buffer is full

      // if we can process some data, go for it; make sure
      // we leave an 'fsize's worth of data, though
      if (xtb.start + xtb.fsize < xtb.valid) {
         int amount = (xtb.valid - xtb.fsize) - xtb.start;
         int n;
         assert(amount > 0);
         n = stb_compress_chunk(xtb.buffer, xtb.buffer + xtb.start, xtb.buffer + xtb.valid,
                                amount, &xtb.pending_literals, xtb.chash, xtb.hashmask);
         xtb.start += n;
      }

      assert(xtb.start + xtb.fsize >= xtb.valid);
      // at this point, our future size is too small, so we
      // need to flush some history. we, in fact, flush exactly
      // one window's worth of history

      {
         int flush = xtb.window;
         assert(xtb.start >= flush);
         assert(xtb.valid >= flush);

         // if 'pending literals' extends back into the shift region,
         // write them out
         if (xtb.start - xtb.pending_literals < flush) {
            outliterals(xtb.buffer + xtb.start - xtb.pending_literals, xtb.pending_literals);
            xtb.pending_literals = 0;
         }

         // now shift the window
         memmove(xtb.buffer, xtb.buffer + flush, xtb.valid - flush);
         xtb.start -= flush;
         xtb.valid -= flush;
   
         for (i=0; i <= xtb.hashmask; ++i)
            if (xtb.chash[i] < xtb.buffer + flush)
               xtb.chash[i] = NULL;
            else
               xtb.chash[i] -= flush;
      }
      // and now that we've made room for more data, go back to the top
   }
}

int stb_compress_stream_start(FILE *f)
{
   stb__out = NULL;
   stb__outfile = f;

   if (f == NULL)
      return 0;

   if (!stb_compress_streaming_start())
      return 0;

   return 1;
}

void stb_compress_stream_end(int close)
{
   stb_compress_streaming_end();
   if (close && stb__outfile) {
      fclose(stb__outfile);
   }
}

#endif // STB_DEFINE



#ifndef WIN32
#define STB_NO_THREADS
#endif

#ifndef STB_NO_THREADS
//////////////////////////////////////////////////////////////////////////////
//
//                         Threads
//


typedef void * (*stb_thread_func)(void *);

// do not rely on these types, this is an implementation detail.
// compare against STB_THREAD_NULL and ST_SEMAPHORE_NULL
typedef void *stb_thread;
typedef void *stb_semaphore;
typedef void *stb_mutex;
typedef struct stb__sync *stb_sync;

#define STB_SEMAPHORE_NULL    NULL
#define STB_THREAD_NULL       NULL
#define STB_MUTEX_NULL        NULL
#define STB_SYNC_NULL         NULL

// get the number of processors (limited to those in the affinity mask for this process).
STB_EXTERN int stb_processor_count(void);
// force to run on a single core -- needed for RDTSC to work, e.g. for iprof
STB_EXTERN void stb_force_uniprocessor(void);

// stb_work functions: queue up work to be done by some worker threads

// set number of threads to serve the queue; you can change this on the fly,
// but if you decrease it, it won't decrease until things currently on the
// queue are finished
STB_EXTERN void          stb_work_numthreads(int n);
// set maximum number of units in the queue; you can only set this BEFORE running any work functions
STB_EXTERN int           stb_work_maxunits(int n);
// enqueue some work to be done (can do this from any thread, or even from a piece of work);
// return value of f is stored in *return_code if non-NULL
STB_EXTERN int           stb_work(stb_thread_func f, void *d, volatile void **return_code);
// as above, but stb_sync_reach is called on 'rel' after work is complete
STB_EXTERN int           stb_work_reach(stb_thread_func f, void *d, volatile void **return_code, stb_sync rel);


// necessary to call this when using volatile to order writes/reads
STB_EXTERN void          stb_barrier(void);

// support for independent queues with their own threads

typedef struct stb__workqueue stb_workqueue;

STB_EXTERN stb_workqueue*stb_workq_new(int numthreads, int max_units);
STB_EXTERN stb_workqueue*stb_workq_new_flags(int numthreads, int max_units, int no_add_mutex, int no_remove_mutex);
STB_EXTERN void          stb_workq_delete(stb_workqueue *q);
STB_EXTERN void          stb_workq_numthreads(stb_workqueue *q, int n);
STB_EXTERN int           stb_workq(stb_workqueue *q, stb_thread_func f, void *d, volatile void **return_code);
STB_EXTERN int           stb_workq_reach(stb_workqueue *q, stb_thread_func f, void *d, volatile void **return_code, stb_sync rel);
STB_EXTERN int           stb_workq_length(stb_workqueue *q);

STB_EXTERN stb_thread    stb_create_thread (stb_thread_func f, void *d);
STB_EXTERN stb_thread    stb_create_thread2(stb_thread_func f, void *d, volatile void **return_code, stb_semaphore rel);
STB_EXTERN void          stb_destroy_thread(stb_thread t);

STB_EXTERN stb_semaphore stb_sem_new(int max_val);
STB_EXTERN stb_semaphore stb_sem_new_extra(int max_val, int start_val);
STB_EXTERN void          stb_sem_delete (stb_semaphore s);
STB_EXTERN void          stb_sem_waitfor(stb_semaphore s);
STB_EXTERN void          stb_sem_release(stb_semaphore s);

STB_EXTERN stb_mutex     stb_mutex_new(void);
STB_EXTERN void          stb_mutex_delete(stb_mutex m);
STB_EXTERN void          stb_mutex_begin(stb_mutex m);
STB_EXTERN void          stb_mutex_end(stb_mutex m);

STB_EXTERN stb_sync      stb_sync_new(void);
STB_EXTERN void          stb_sync_delete(stb_sync s);
STB_EXTERN int           stb_sync_set_target(stb_sync s, int count);
STB_EXTERN void          stb_sync_reach_and_wait(stb_sync s);    // wait for 'target' reachers
STB_EXTERN int           stb_sync_reach(stb_sync s);

typedef struct stb__threadqueue stb_threadqueue;
#define STB_THREADQ_DYNAMIC   0
STB_EXTERN stb_threadqueue *stb_threadq_new(int item_size, int num_items, int many_add, int many_remove);
STB_EXTERN void             stb_threadqueue_delete(stb_threadqueue *tq);
STB_EXTERN int              stb_threadq_get(stb_threadqueue *tq, void *output);
STB_EXTERN void             stb_threadq_get_block(stb_threadqueue *tq, void *output);
STB_EXTERN int              stb_threadq_add(stb_threadqueue *tq, void *input);
// can return FALSE if STB_THREADQ_DYNAMIC and attempt to grow fails
STB_EXTERN int              stb_threadq_add_block(stb_threadqueue *tq, void *input);

#ifdef STB_DEFINE

typedef struct
{
   stb_thread_func f;
   void *d;
   volatile void **return_val;
   stb_semaphore sem;
} stb__thread;

// this is initialized along all possible paths to create threads, therefore
// it's always initialized before any other threads are create, therefore
// it's free of races AS LONG AS you only create threads through stb_*
static stb_mutex stb__threadmutex, stb__workmutex;

static void stb__threadmutex_init(void)
{
   if (stb__threadmutex == STB_SEMAPHORE_NULL) {
      stb__threadmutex = stb_mutex_new();
      stb__workmutex = stb_mutex_new();
   }
}

#ifdef STB_THREAD_TEST
volatile float stb__t1=1, stb__t2;

static void stb__wait(int n)
{
   float z = 0;
   int i;
   for (i=0; i < n; ++i)
      z += 1 / (stb__t1+i);
   stb__t2 = z;
}
#else
#define stb__wait(x)
#endif

#ifdef _WIN32

// avoid including windows.h -- note that our definitions aren't
// exactly the same (we don't define the security descriptor struct)
// so if you want to include windows.h, make sure you do it first.
#include <process.h>

#ifndef _WINDOWS_  // check windows.h guard
#define STB__IMPORT   STB_EXTERN __declspec(dllimport)
#define STB__DW       unsigned long

STB__IMPORT int     __stdcall TerminateThread(void *, STB__DW);
STB__IMPORT void *  __stdcall CreateSemaphoreA(void *sec, long,long,char*);
STB__IMPORT int     __stdcall CloseHandle(void *);
STB__IMPORT STB__DW __stdcall WaitForSingleObject(void *, STB__DW);
STB__IMPORT int     __stdcall ReleaseSemaphore(void *, long, long *);
STB__IMPORT void    __stdcall Sleep(STB__DW);
#endif

// necessary to call this when using volatile to order writes/reads
void stb_barrier(void)
{
   #ifdef MemoryBarrier
   MemoryBarrier();
   #else
   long temp;
   __asm xchg temp,eax;
   #endif
}

static void stb__thread_run(void *t)
{
   void *res;
   stb__thread info = * (stb__thread *) t;
   free(t);
   res = info.f(info.d);
   if (info.return_val)
      *info.return_val = res;
   if (info.sem != STB_SEMAPHORE_NULL)
      stb_sem_release(info.sem);
}

static stb_thread stb_create_thread_raw(stb_thread_func f, void *d, volatile void **return_code, stb_semaphore rel)
{
#ifdef _MT
#if defined(STB_FASTMALLOC) && !defined(STB_FASTMALLOC_ITS_OKAY_I_ONLY_MALLOC_IN_ONE_THREAD)
   stb_fatal("Error! Cannot use STB_FASTMALLOC with threads.\n");
   return STB_THREAD_NULL;
#else
   unsigned long id;
   stb__thread *data = (stb__thread *) malloc(sizeof(*data));
   if (!data) return NULL;
   stb__threadmutex_init();
   data->f = f;
   data->d = d;
   data->return_val = return_code;
   data->sem = rel;
   id = _beginthread(stb__thread_run, 0, data);
   if (id == -1) return NULL;
   return (void *) id;
#endif
#else
   stb_fatal("Must compile mult-threaded to use stb_thread/stb_work.");
   return NULL;
#endif
}

// trivial win32 wrappers
void          stb_destroy_thread(stb_thread t)   { TerminateThread(t,0); }
stb_semaphore stb_sem_new(int maxv)                {return CreateSemaphoreA(NULL,0,maxv,NULL); }
stb_semaphore stb_sem_new_extra(int maxv,int start){return CreateSemaphoreA(NULL,start,maxv,NULL); }
void          stb_sem_delete(stb_semaphore s)    { if (s != NULL) CloseHandle(s); }
void          stb_sem_waitfor(stb_semaphore s)   { WaitForSingleObject(s, 0xffffffff); } // INFINITE
void          stb_sem_release(stb_semaphore s)   { ReleaseSemaphore(s,1,NULL); }
static void   stb__thread_sleep(int ms)          { Sleep(ms); }

#ifndef _WINDOWS_
STB__IMPORT int __stdcall GetProcessAffinityMask(void *, STB__DW *, STB__DW *);
STB__IMPORT void * __stdcall GetCurrentProcess(void);
STB__IMPORT int __stdcall SetProcessAffinityMask(void *, STB__DW);
#endif

int stb_processor_count(void)
{
   unsigned long proc,sys;
   GetProcessAffinityMask(GetCurrentProcess(), &proc, &sys);
   return stb_bitcount(proc);
}

void stb_force_uniprocessor(void)
{
   unsigned long proc,sys;
   GetProcessAffinityMask(GetCurrentProcess(), &proc, &sys);
   if (stb_bitcount(proc) > 1) {
      int z;
      for (z=0; z < 32; ++z)
         if (proc & (1 << z))
            break;
      if (z < 32) {
         proc = 1 << z;
         SetProcessAffinityMask(GetCurrentProcess(), proc);
      }
   }
}

#ifdef _WINDOWS_
#define STB_MUTEX_NATIVE
DWORD foob;
void *stb_mutex_new(void)
{
   CRITICAL_SECTION *p = (CRITICAL_SECTION *) malloc(sizeof(*p));
   if (p)
#if _WIN32_WINNT >= 0x0500
      InitializeCriticalSectionAndSpinCount(p, 500);
#else
      InitializeCriticalSection(p);
#endif
   return p;
}

void stb_mutex_delete(void *p)
{
   if (p) {
      DeleteCriticalSection((CRITICAL_SECTION *) p);
      free(p);
   }
}

void stb_mutex_begin(void *p)
{
   stb__wait(500);
   if (p)
      EnterCriticalSection((CRITICAL_SECTION *) p);
}

void stb_mutex_end(void *p)
{
   if (p)
      LeaveCriticalSection((CRITICAL_SECTION *) p);
   stb__wait(500);
}
#endif // _WINDOWS_

#if 0
// for future reference, 
// InterlockedCompareExchange for x86:
 int cas64_mp(void * dest, void * xcmp, void * xxchg) {
        __asm
        {
                mov             esi, [xxchg]            ; exchange
                mov             ebx, [esi + 0]
                mov             ecx, [esi + 4]

                mov             esi, [xcmp]                     ; comparand
                mov             eax, [esi + 0]
                mov             edx, [esi + 4]

                mov             edi, [dest]                     ; destination
                lock cmpxchg8b  [edi]
                jz              yyyy;

                mov             [esi + 0], eax;
                mov             [esi + 4], edx;

yyyy:
                xor             eax, eax;
                setz    al;
        };

inline unsigned __int64 _InterlockedCompareExchange64(volatile unsigned __int64 *dest
                           ,unsigned __int64 exchange
                           ,unsigned __int64 comperand)
{
    //value returned in eax::edx
    __asm {
        lea esi,comperand;
        lea edi,exchange;

        mov eax,[esi];
        mov edx,4[esi];
        mov ebx,[edi];
        mov ecx,4[edi];
        mov esi,dest;
        lock CMPXCHG8B [esi];
    } 
#endif // #if 0

#endif // _WIN32

stb_thread stb_create_thread2(stb_thread_func f, void *d, volatile void **return_code, stb_semaphore rel)
{
   return stb_create_thread_raw(f,d,return_code,rel);
}

stb_thread stb_create_thread(stb_thread_func f, void *d)
{
   return stb_create_thread2(f,d,NULL,STB_SEMAPHORE_NULL);
}

// mutex implemented by wrapping semaphore
#ifndef STB_MUTEX_NATIVE
stb_mutex stb_mutex_new(void)            { return stb_sem_new_extra(1,1); }
void      stb_mutex_delete(stb_mutex m)  { stb_sem_delete (m);      }
void      stb_mutex_begin(stb_mutex m)   { stb__wait(500); if (m) stb_sem_waitfor(m); }
void      stb_mutex_end(stb_mutex m)     { if (m) stb_sem_release(m); stb__wait(500); }
#endif

// thread merge operation
struct stb__sync
{
   int target;  // target number of threads to hit it
   int sofar;   // total threads that hit it
   int waiting; // total threads waiting

   stb_mutex start;   // mutex to prevent starting again before finishing previous
   stb_mutex mutex;   // mutex while tweaking state
   stb_semaphore release; // semaphore wake up waiting threads
      // we have to wake them up one at a time, rather than using a single release
      // call, because win32 semaphores don't let you dynamically change the max count!
};

stb_sync stb_sync_new(void)
{
   stb_sync s = (stb_sync) malloc(sizeof(*s));
   if (!s) return s;

   s->target = s->sofar = s->waiting = 0;
   s->mutex   = stb_mutex_new();
   s->start   = stb_mutex_new();
   s->release = stb_sem_new(1);
   if (s->mutex == STB_MUTEX_NULL || s->release == STB_SEMAPHORE_NULL || s->start == STB_MUTEX_NULL) {
      stb_mutex_delete(s->mutex);
      stb_mutex_delete(s->mutex);
      stb_sem_delete(s->release);
      free(s);
      return NULL;
   }
   return s;
}

void stb_sync_delete(stb_sync s)
{
   if (s->waiting) {
      // it's bad to delete while there are threads waiting!
      // shall we wait for them to reach, or just bail? just bail
      assert(0);
   }
   stb_mutex_delete(s->mutex);
   stb_mutex_delete(s->release);
   free(s);
}

int stb_sync_set_target(stb_sync s, int count)
{
   // don't allow setting a target until the last one is fully released;
   // note that this can lead to inefficient pipelining, and maybe we'd
   // be better off ping-ponging between two internal syncs?
   // I tried seeing how often this happened using TryEnterCriticalSection
   // and could _never_ get it to happen in imv(stb), even with more threads
   // than processors. So who knows!
   stb_mutex_begin(s->start);

   // this mutex is pointless, since it's not valid for threads
   // to call reach() before anyone calls set_target() anyway
   stb_mutex_begin(s->mutex);

   assert(s->target == 0); // enforced by start mutex
   s->target  = count;
   s->sofar   = 0;
   s->waiting = 0;
   stb_mutex_end(s->mutex);
   return TRUE;
}

void stb__sync_release(stb_sync s)
{
   if (s->waiting)
      stb_sem_release(s->release);
   else {
      s->target = 0;
      stb_mutex_end(s->start);
   }
}

int stb_sync_reach(stb_sync s)
{
   int n;
   stb_mutex_begin(s->mutex);
   assert(s->sofar < s->target);
   n = ++s->sofar; // record this value to avoid possible race if we did 'return s->sofar';
   if (s->sofar == s->target)
      stb__sync_release(s);
   stb_mutex_end(s->mutex);
   return n;
}

void stb_sync_reach_and_wait(stb_sync s)
{
   stb_mutex_begin(s->mutex);
   assert(s->sofar < s->target);
   ++s->sofar;
   if (s->sofar == s->target) {
      stb__sync_release(s);
      stb_mutex_end(s->mutex);
   } else {
      ++s->waiting; // we're waiting, so one more waiter
      stb_mutex_end(s->mutex); // release the mutex to other threads

      stb_sem_waitfor(s->release); // wait for merge completion

      stb_mutex_begin(s->mutex); // on merge completion, grab the mutex
      --s->waiting; // we're done waiting
      stb__sync_release(s);
      stb_mutex_end(s->mutex); // and now we're done
      // this ends the same as the first case, but it's a lot
      // clearer to understand without sharing the code
   }
}

struct stb__threadqueue
{
   stb_mutex add, remove;
   stb_semaphore nonempty, nonfull;
   int head_blockers;  // number of threads blocking--used to know whether to release(avail)
   int tail_blockers;
   int head, tail, array_size, growable;
   int item_size;
   char *data;
};

static int stb__tq_wrap(volatile stb_threadqueue *z, int p)
{
   if (p == z->array_size)
      return p - z->array_size;
   else
      return p;
}

int stb__threadq_get_raw(stb_threadqueue *tq2, void *output, int block)
{
   volatile stb_threadqueue *tq = (volatile stb_threadqueue *) tq2;
   if (tq->head == tq->tail && !block) return 0;

   stb_mutex_begin(tq->remove);

   while (tq->head == tq->tail) {
      if (!block) {
         stb_mutex_end(tq->remove);
         return 0;
      }
      ++tq->head_blockers;
      stb_mutex_end(tq->remove);

      stb_sem_waitfor(tq->nonempty);

      stb_mutex_begin(tq->remove);
      --tq->head_blockers;
   }

   memcpy(output, tq->data + tq->head*tq->item_size, tq->item_size);
   stb_barrier();
   tq->head = stb__tq_wrap(tq, tq->head+1);

   stb_sem_release(tq->nonfull);
   if (tq->head_blockers) // can't check if actually non-empty due to race?
      stb_sem_release(tq->nonempty); // if there are other blockers, wake one

   stb_mutex_end(tq->remove);
   return TRUE;
}

int stb__threadq_grow(volatile stb_threadqueue *tq)
{
   int n;
   char *p;
   assert(tq->remove != STB_MUTEX_NULL); // must have this to allow growth!
   stb_mutex_begin(tq->remove);

   n = tq->array_size * 2;
   p = (char *) realloc(tq->data, n * tq->item_size);
   if (p == NULL) {
      stb_mutex_end(tq->remove);
      stb_mutex_end(tq->add);
      return FALSE;
   }
   if (tq->tail < tq->head) {
      memcpy(p + tq->array_size * tq->item_size, p, tq->tail * tq->item_size);
      tq->tail += tq->array_size;
   }
   tq->data = p;
   tq->array_size = n;

   stb_mutex_end(tq->remove);
   return TRUE;
}

int stb__threadq_add_raw(stb_threadqueue *tq2, void *input, int block)
{
   int tail,pos;
   volatile stb_threadqueue *tq = (volatile stb_threadqueue *) tq2;
   stb_mutex_begin(tq->add);
   for(;;) {
      pos = tq->tail;
      tail = stb__tq_wrap(tq, pos+1);
      if (tail != tq->head) break;

      // full
      if (tq->growable) {
         if (!stb__threadq_grow(tq)) {
            stb_mutex_end(tq->add);
            return FALSE; // out of memory
         }
      } else if (!block) {
         stb_mutex_end(tq->add);
         return FALSE;
      } else {
         ++tq->tail_blockers;
         stb_mutex_end(tq->add);

         stb_sem_waitfor(tq->nonfull);

         stb_mutex_begin(tq->add);
         --tq->tail_blockers;
      }
   }
   memcpy(tq->data + tq->item_size * pos, input, tq->item_size);
   stb_barrier();
   tq->tail = tail;
   stb_sem_release(tq->nonempty);
   if (tq->tail_blockers) // can't check if actually non-full due to race?
      stb_sem_release(tq->nonfull);
   stb_mutex_end(tq->add);
   return TRUE;
}

int stb_threadq_length(stb_threadqueue *tq2)
{
   int a,b,n;
   volatile stb_threadqueue *tq = (volatile stb_threadqueue *) tq2;
   stb_mutex_begin(tq->add);
   a = tq->head;
   b = tq->tail;
   n = tq->array_size;
   stb_mutex_end(tq->add);
   if (a > b) b += n;
   return b-a;
}

int stb_threadq_get(stb_threadqueue *tq, void *output)
{
   return stb__threadq_get_raw(tq, output, FALSE);
}

void stb_threadq_get_block(stb_threadqueue *tq, void *output)
{
   stb__threadq_get_raw(tq, output, TRUE);
}

int stb_threadq_add(stb_threadqueue *tq, void *input)
{
   return stb__threadq_add_raw(tq, input, FALSE);
}

int stb_threadq_add_block(stb_threadqueue *tq, void *input)
{
   return stb__threadq_add_raw(tq, input, TRUE);
}

void stb_threadq_delete(stb_threadqueue *tq)
{
   if (tq) {
      free(tq->data);
      stb_mutex_delete(tq->add);
      stb_mutex_delete(tq->remove);
      stb_sem_delete(tq->nonempty);
      stb_sem_delete(tq->nonfull);
      free(tq);
   }
}

#define STB_THREADQUEUE_DYNAMIC   0
stb_threadqueue *stb_threadq_new(int item_size, int num_items, int many_add, int many_remove)
{
   int error=0;
   stb_threadqueue *tq = (stb_threadqueue *) malloc(sizeof(*tq));
   if (tq == NULL) return NULL;

   if (num_items == STB_THREADQUEUE_DYNAMIC) {
      tq->growable = TRUE;
      num_items = 32;
   } else
      tq->growable = FALSE;

   tq->item_size = item_size;
   tq->array_size = num_items+1;

   tq->add = tq->remove = STB_MUTEX_NULL;
   tq->nonempty = tq->nonfull = STB_SEMAPHORE_NULL;
   tq->data = NULL;
   if (many_add)
      { tq->add    = stb_mutex_new(); if (tq->add    == STB_MUTEX_NULL) goto error; }
   if (many_remove || tq->growable)
      { tq->remove = stb_mutex_new(); if (tq->remove == STB_MUTEX_NULL) goto error; }
   tq->nonempty = stb_sem_new(1); if (tq->nonempty == STB_SEMAPHORE_NULL) goto error;
   tq->nonfull  = stb_sem_new(1); if (tq->nonfull  == STB_SEMAPHORE_NULL) goto error;
   tq->data = (char *) malloc(tq->item_size * tq->array_size);
   if (tq->data == NULL) goto error;

   tq->head = tq->tail = 0;
   tq->head_blockers = tq->tail_blockers = 0;

   return tq;

error:
   stb_threadq_delete(tq);
   return NULL;
}

typedef struct
{
   stb_thread_func f;
   void *d;
   volatile void **retval;
   stb_sync sync;
} stb__workinfo;

static volatile stb__workinfo *stb__work;

struct stb__workqueue
{
   int numthreads;
   stb_threadqueue *tq;
};

static void *stb__thread_workloop(void *p)
{
   volatile stb_workqueue *q = (volatile stb_workqueue *) p;
   for(;;) {
      void *z;
      stb__workinfo w;
      stb_threadq_get_block(q->tq, &w);
      if (w.f == NULL) // null work is a signal to end the thread
         return NULL;
      z = w.f(w.d);
      if (w.retval) { stb_barrier(); *w.retval = z; }
      if (w.sync != STB_SYNC_NULL) stb_sync_reach(w.sync);
   }
}

static stb_workqueue *stb__work_global;

stb_workqueue *stb_workq_new(int num_threads, int max_units)
{
   return stb_workq_new_flags(num_threads, max_units, 0,0);
}

stb_workqueue *stb_workq_new_flags(int numthreads, int max_units, int no_add_mutex, int no_remove_mutex)
{
   stb_workqueue *q = (stb_workqueue *) malloc(sizeof(*q));
   if (q == NULL) return NULL;
   q->tq = stb_threadq_new(sizeof(stb__workinfo), max_units, !no_add_mutex, !no_remove_mutex);
   if (q->tq == NULL) { free(q); return NULL; }
   q->numthreads = 0;
   stb_workq_numthreads(q, numthreads);
   return q;
}

void stb_workq_delete(stb_workqueue *q)
{
   while (stb_workq_length(q) != 0)
      stb__thread_sleep(1);
   stb_threadq_delete(q->tq);
   free(q);
}

static int stb__work_maxitems = STB_THREADQUEUE_DYNAMIC;

static void stb_work_init(int num_threads)
{
   if (stb__work_global == NULL) {
      stb__threadmutex_init();
      stb_mutex_begin(stb__workmutex);
      stb_barrier();
      if (*(stb_workqueue * volatile *) &stb__work_global == NULL)
         stb__work_global = stb_workq_new(num_threads, stb__work_maxitems);
      stb_mutex_end(stb__workmutex);
   }
}

static int stb__work_raw(stb_workqueue *q, stb_thread_func f, void *d, volatile void **return_code, stb_sync rel)
{
   stb__workinfo w;
   if (q == NULL) {
      stb_work_init(1);
      q = stb__work_global;
   }
   w.f = f;
   w.d = d;
   w.retval = return_code;
   w.sync = rel;
   return stb_threadq_add(q->tq, &w);
}

int stb_workq_length(stb_workqueue *q)
{
   return stb_threadq_length(q->tq);
}

int stb_workq(stb_workqueue *q, stb_thread_func f, void *d, volatile void **return_code)
{
   if (f == NULL) return 0;
   return stb_workq_reach(q, f, d, return_code, NULL);
}

int stb_workq_reach(stb_workqueue *q, stb_thread_func f, void *d, volatile void **return_code, stb_sync rel)
{
   if (f == NULL) return 0;
   return stb__work_raw(q, f, d, return_code, rel);
}

static void stb__workq_numthreads(stb_workqueue *q, int n)
{
   while (q->numthreads < n) {
      stb_create_thread(stb__thread_workloop, q);
      ++q->numthreads;
   }
   while (q->numthreads > n) {
      stb__work_raw(q, NULL, NULL, NULL, NULL);
      --q->numthreads;
   }
}

void stb_workq_numthreads(stb_workqueue *q, int n)
{
   stb_mutex_begin(stb__threadmutex);
   stb__workq_numthreads(q,n);
   stb_mutex_end(stb__threadmutex);
}

int stb_work_maxunits(int n)
{
   if (stb__work_global == NULL) {
      stb__work_maxitems = n;
      stb_work_init(1);
   }
   return stb__work_maxitems;
}

int stb_work(stb_thread_func f, void *d, volatile void **return_code)
{
   return stb_workq(stb__work_global, f,d,return_code);
}

int stb_work_reach(stb_thread_func f, void *d, volatile void **return_code, stb_sync rel)
{
   return stb_workq_reach(stb__work_global, f,d,return_code,rel);
}

void stb_work_numthreads(int n)
{
   if (stb__work_global == NULL)
      stb_work_init(n);
   else
      stb_workq_numthreads(stb__work_global, n);
}
#endif // STB_DEFINE

//////////////////////////////////////////////////////////////////////////////
//
// Background disk I/O
//
//

#define STB_BGIO_READ_ALL   (-1)
STB_EXTERN int stb_bgio_read    (char *filename, int offset, int len, stb_uchar **result, int *olen);
STB_EXTERN int stb_bgio_readf   (FILE *f       , int offset, int len, stb_uchar **result, int *olen);
STB_EXTERN int stb_bgio_read_to (char *filename, int offset, int len, stb_uchar  *buffer, int *olen);
STB_EXTERN int stb_bgio_readf_to(FILE *f       , int offset, int len, stb_uchar  *buffer, int *olen);

#ifdef STB_DEFINE

static stb_workqueue *stb__diskio;
static stb_mutex stb__diskio_mutex;

typedef struct
{
   char *filename;
   FILE *f;
   int offset;
   int len;

   stb_uchar *output;
   stb_uchar **result;
   int *len_output;
   int *flag;
} stb__disk_command;

#define STB__MAX_DISK_COMMAND 100
static stb__disk_command stb__dc_queue[STB__MAX_DISK_COMMAND];
static int stb__dc_offset;

void stb__io_init(void)
{
   if (!stb__diskio) {
      stb__threadmutex_init();
      stb_mutex_begin(stb__threadmutex);
      stb_barrier();
      if (*(stb_thread * volatile *) &stb__diskio == NULL) {
         stb__diskio_mutex = stb_mutex_new();
         stb__diskio = stb_workq_new_flags(1,STB__MAX_DISK_COMMAND,TRUE,TRUE); // no remove mutex
      }
      stb_mutex_end(stb__threadmutex);
   }
}

static void * stb__io_error(stb__disk_command *dc)
{
   if (dc->len_output) *dc->len_output = 0;
   if (dc->result) *dc->result = NULL;
   if (dc->flag) *dc->flag = -1;
   return NULL;
}

static void * stb__io_task(void *p)
{
   stb__disk_command *dc = (stb__disk_command *) p;
   int len;
   FILE *f;
   stb_uchar *buf;

   if (dc->f)
      f = dc->f;
   else {
      f = fopen(dc->filename, "rb");
      free(dc->filename);
      if (!f)
         return stb__io_error(dc);
   }

   len = dc->len;
   if (len < 0) {
      fseek(f, 0, SEEK_END);
      len = ftell(f) - dc->offset;
   }

   if (!fseek(f, dc->offset, SEEK_SET))
      return stb__io_error(dc);

   if (dc->output)
      buf = dc->output;
   else {
      buf = (stb_uchar *) malloc(len);
      if (buf == NULL)
         return stb__io_error(dc);
   }

   len = fread(buf, 1, len, f);
   if (dc->len_output) *dc->len_output = len;
   if (dc->result) *dc->result = buf;
   if (dc->flag) *dc->flag = 1;

   return NULL;
}

int stb__io_add(char *fname, FILE *f, int off, int len, stb_uchar *out, stb_uchar **result, int *olen, int *flag)
{
   int res;
   stb__io_init();
   // do memory allocation outside of mutex
   if (fname) fname = strdup(fname);
   stb_mutex_begin(stb__diskio_mutex);
   {
      stb__disk_command *dc = &stb__dc_queue[stb__dc_offset];
      dc->filename = fname;
      dc->f = f;
      dc->offset = off;
      dc->len = len;
      dc->output = out;
      dc->result = result;
      dc->len_output = olen;
      dc->flag = flag;
      res = stb_workq(stb__diskio, stb__io_task, dc, NULL);
      if (res)
         stb__dc_offset = (stb__dc_offset + 1 == STB__MAX_DISK_COMMAND ? 0 : stb__dc_offset+1);
   }
   stb_mutex_end(stb__diskio_mutex);
   return res;
}

int stb_bgio_read(char *filename, int offset, int len, stb_uchar **result, int *olen)
{
   return stb__io_add(filename,NULL,offset,len,NULL,result,olen,NULL);
}

int stb_bgio_readf(FILE *f, int offset, int len, stb_uchar **result, int *olen)
{
   return stb__io_add(NULL,f,offset,len,NULL,result,olen,NULL);
}

int stb_bgio_read_to(char *filename, int offset, int len, stb_uchar *buffer, int *olen)
{
   return stb__io_add(filename,NULL,offset,len,buffer,NULL,olen,NULL);
}

int stb_bgio_readf_to(FILE *f, int offset, int len, stb_uchar *buffer, int *olen)
{
   return stb__io_add(NULL,f,offset,len,buffer,NULL,olen,NULL);
}
#endif
#endif



//////////////////////////////////////////////////////////////////////////////
//
//                         Fast malloc implementation
//
//   This is a clone of TCMalloc, but without the thread support.
//      1. large objects are allocated directly, page-aligned
//      2. small objects are allocated in homogeonous heaps, 0 overhead
//
//   We keep an allocation table for pages a la TCMalloc. This would
//   require 4MB for the entire address space, but we only allocate
//   the parts that are in use. The overhead from using homogenous heaps
//   everywhere is 3MB. (That is, if you allocate 1 object of each size,
//   you'll use 3MB.)

#if defined(STB_DEFINE) && (defined(_WIN32) || defined(STB_FASTMALLOC))

#ifdef _WIN32
   #ifndef _WINDOWS_
   STB__IMPORT void * __stdcall VirtualAlloc(void *p, unsigned long size, unsigned long type, unsigned long protect);
   STB__IMPORT int   __stdcall VirtualFree(void *p, unsigned long size, unsigned long freetype);
   #endif
   #define stb__alloc_pages_raw(x)     (stb_uint32) VirtualAlloc(NULL, (x), 0x3000, 0x04)
   #define stb__dealloc_pages_raw(p)   VirtualFree((void *) p, 0, 0x8000)
#else
   #error "Platform not currently supported"
#endif

typedef struct stb__span
{
   int                start, len;
   struct stb__span  *next, *prev;
   void              *first_free;
   unsigned short     list; // 1..256 free; 257..511 sizeclass; 0=large block
   short              allocations; // # outstanding allocations for sizeclass
} stb__span;  // 24

static stb__span **stb__span_for_page;
static int stb__firstpage, stb__lastpage;
static void stb__update_page_range(int first, int last)
{
   stb__span **sfp;
   int i, f,l;
   if (first >= stb__firstpage && last <= stb__lastpage) return;
   if (stb__span_for_page == NULL) {
      f = first;
      l = f+stb_max(last-f, 16384);
      l = stb_min(l, 1<<20);
   } else if (last > stb__lastpage) {
      f = stb__firstpage;
      l = f + (stb__lastpage - f) * 2;
      l = stb_clamp(last, l,1<<20);
   } else {
      l = stb__lastpage;
      f = l - (l - stb__firstpage) * 2;
      f = stb_clamp(f, 0,first);
   }
   sfp = (stb__span **) stb__alloc_pages_raw(sizeof(void *) * (l-f));
   for (i=f; i < stb__firstpage; ++i) sfp[i - f] = NULL;
   for (   ; i < stb__lastpage ; ++i) sfp[i - f] = stb__span_for_page[i - stb__firstpage];
   for (   ; i < l             ; ++i) sfp[i - f] = NULL;
   if (stb__span_for_page) stb__dealloc_pages_raw(stb__span_for_page);
   stb__firstpage = f;
   stb__lastpage  = l;
   stb__span_for_page = sfp;
}

static stb__span *stb__span_free=NULL;
static stb__span *stb__span_first, *stb__span_end;
static stb__span *stb__span_alloc(void)
{
   stb__span *s = stb__span_free;
   if (s)
      stb__span_free = s->next;
   else {
      if (!stb__span_first) {
         stb__span_first = (stb__span *) stb__alloc_pages_raw(65536);
         if (stb__span_first == NULL) return NULL;
         stb__span_end = stb__span_first + (65536 / sizeof(stb__span));
      }
      s = stb__span_first++;
      if (stb__span_first == stb__span_end) stb__span_first = NULL;
   }
   return s;
}

static stb__span *stb__spanlist[512];

static void stb__spanlist_unlink(stb__span *s)
{
   if (s->prev)
      s->prev->next = s->next;
   else {
      int n = s->list;
      assert(stb__spanlist[n] == s);
      stb__spanlist[n] = s->next;
   }
   if (s->next)
      s->next->prev = s->prev;
   s->next = s->prev = NULL;
   s->list = 0;
}

static void stb__spanlist_add(int n, stb__span *s)
{
   s->list = n;
   s->next = stb__spanlist[n];
   s->prev = NULL;
   stb__spanlist[n] = s;
   if (s->next) s->next->prev = s;
}

#define stb__page_shift       12
#define stb__page_size        (1 << stb__page_shift)
#define stb__page_number(x)   ((x) >> stb__page_shift)
#define stb__page_address(x)  ((x) << stb__page_shift)

static void stb__set_span_for_page(stb__span *s)
{
   int i;
   for (i=0; i < s->len; ++i)
      stb__span_for_page[s->start + i - stb__firstpage] = s;
}

static stb__span *stb__coalesce(stb__span *a, stb__span *b)
{
   assert(a->start + a->len == b->start);
   if (a->list) stb__spanlist_unlink(a);
   if (b->list) stb__spanlist_unlink(b);
   a->len += b->len;
   b->len = 0;
   b->next = stb__span_free;
   stb__span_free = b;
   stb__set_span_for_page(a);
   return a;
}

static void stb__free_span(stb__span *s)
{
   stb__span *n = NULL;
   if (s->start > stb__firstpage) {
      n = stb__span_for_page[s->start-1 - stb__firstpage];
      if (n && n->allocations == -2 && n->start + n->len == s->start) s = stb__coalesce(n,s);
   }
   if (s->start + s->len < stb__lastpage) {
      n = stb__span_for_page[s->start + s->len - stb__firstpage];
      if (n && n->allocations == -2 && s->start + s->len == n->start) s = stb__coalesce(s,n);
   }
   s->allocations = -2;
   stb__spanlist_add(s->len > 256 ? 256 : s->len, s);
}

static stb__span *stb__alloc_pages(int num)
{
   stb__span *s = stb__span_alloc();
   int p;
   if (!s) return NULL;
   p = stb__alloc_pages_raw(num << stb__page_shift);
   if (p == 0) { s->next = stb__span_free; stb__span_free = s; return 0; }
   assert(stb__page_address(stb__page_number(p)) == p);
   p = stb__page_number(p);
   stb__update_page_range(p, p+num);
   s->start = p;
   s->len   = num;
   s->next  = NULL;
   s->prev  = NULL;
   stb__set_span_for_page(s);
   return s;
}

static stb__span *stb__alloc_span(int pagecount)
{
   int i;
   stb__span *p = NULL;
   for(i=pagecount; i < 256; ++i)
      if (stb__spanlist[i]) {
         p = stb__spanlist[i];
         break;
      }
   if (!p) {
      p = stb__spanlist[256];
      while (p && p->len < pagecount)
         p = p->next;
   }
   if (!p) {
      p = stb__alloc_pages(pagecount < 16 ? 16 : pagecount);
      if (p == NULL) return 0;
   } else
      stb__spanlist_unlink(p);
      
   if (p->len > pagecount) {
      stb__span *q = stb__span_alloc();
      if (q) {
         q->start = p->start + pagecount;
         q->len   = p->len   - pagecount;
         p->len   = pagecount;
         for (i=0; i < q->len; ++i)
            stb__span_for_page[q->start+i - stb__firstpage] = q;
         stb__spanlist_add(q->len > 256 ? 256 : q->len, q);
      }
   }
   return p;
}

#define STB__MAX_SMALL_SIZE     32768
#define STB__MAX_SIZE_CLASSES   256

static unsigned char stb__class_base[32];
static unsigned char stb__class_shift[32];
static unsigned char stb__pages_for_class[STB__MAX_SIZE_CLASSES];
static           int stb__size_for_class[STB__MAX_SIZE_CLASSES];

stb__span *stb__get_nonempty_sizeclass(int c)
{
   int s = c + 256, i, size, tsize; // remap to span-list index
   char *z;
   void *q;
   stb__span *p = stb__spanlist[s];
   if (p) {
      if (p->first_free) return p; // fast path: it's in the first one in list
      for (p=p->next; p; p=p->next)
         if (p->first_free) {
            // move to front for future queries
            stb__spanlist_unlink(p);
            stb__spanlist_add(s, p);
            return p;
         }
   }
   // no non-empty ones, so allocate a new one
   p = stb__alloc_span(stb__pages_for_class[c]);
   if (!p) return NULL;
   // create the free list up front
   size = stb__size_for_class[c];
   tsize = stb__pages_for_class[c] << stb__page_shift;
   i = 0;
   z = (char *) stb__page_address(p->start);
   q = NULL;
   while (i + size <= tsize) {
      * (void **) z = q; q = z;
      z += size;
      i += size;
   }
   p->first_free = q;
   p->allocations = 0;
   stb__spanlist_add(s,p);
   return p;
}

static int stb__sizeclass(size_t sz)
{
   int z = stb_log2_floor(sz); // -1 below to group e.g. 13,14,15,16 correctly
   return stb__class_base[z] + ((sz-1) >> stb__class_shift[z]);
}

static void stb__init_sizeclass(void)
{
   int i, size, overhead;
   int align_shift = 2;  // allow 4-byte and 12-byte blocks as well, vs. TCMalloc
   int next_class = 1;
   int last_log = 0;

   for (i = 0; i < align_shift; i++) {
      stb__class_base [i] = next_class;
      stb__class_shift[i] = align_shift;
   }

   for (size = 1 << align_shift; size <= STB__MAX_SMALL_SIZE; size += 1 << align_shift) {
      i = stb_log2_floor(size);
      if (i > last_log) {
         if (size == 16) ++align_shift; // switch from 4-byte to 8-byte alignment
         else if (size >= 128 && align_shift < 8) ++align_shift;
         stb__class_base[i]  = next_class - ((size-1) >> align_shift);
         stb__class_shift[i] = align_shift;
         last_log = i;
      }
      stb__size_for_class[next_class++] = size;
   }

   for (i=1; i <= STB__MAX_SMALL_SIZE; ++i)
      assert(i <= stb__size_for_class[stb__sizeclass(i)]);

   overhead = 0;
   for (i = 1; i < next_class; i++) {
      int s = stb__size_for_class[i];
      size = stb__page_size;
      while (size % s > size >> 3)
         size += stb__page_size;
      stb__pages_for_class[i] = (unsigned char) (size >> stb__page_shift);
      overhead += size;
   }
   assert(overhead < (4 << 20)); // make sure it's under 4MB of overhead
}

#ifdef STB_DEBUG
#define stb__smemset(a,b,c)  memset((void *) a, b, c)
#elif defined(STB_FASTMALLOC_INIT)
#define stb__smemset(a,b,c)  memset((void *) a, b, c)
#else
#define stb__smemset(a,b,c)
#endif
void *stb_smalloc(size_t sz)
{
   stb__span *s;
   if (sz == 0) return NULL;
   if (stb__size_for_class[1] == 0) stb__init_sizeclass();
   if (sz > STB__MAX_SMALL_SIZE) {
      s = stb__alloc_span((sz + stb__page_size - 1) >> stb__page_shift);
      if (s == NULL) return NULL;
      s->list = 0;
      s->next = s->prev = NULL;
      s->allocations = -32767;
      stb__smemset(stb__page_address(s->start), 0xcd, (sz+3)&~3);
      return (void *) stb__page_address(s->start);
   } else {
      void *p;
      int c = stb__sizeclass(sz);
      s = stb__spanlist[256+c];
      if (!s || !s->first_free)
         s = stb__get_nonempty_sizeclass(c);
      if (s == NULL) return NULL;
      p = s->first_free;
      s->first_free = * (void **) p;
      ++s->allocations;
      stb__smemset(p,0xcd, sz);
      return p;
   }
}

int stb_ssize(void *p)
{
   stb__span *s;
   if (p == NULL) return 0;
   s = stb__span_for_page[stb__page_number((stb_uint) p) - stb__firstpage];
   if (s->list >= 256) {
      return stb__size_for_class[s->list - 256];
   } else {
      assert(s->list == 0);
      return s->len << stb__page_shift;
   }
}

void stb_sfree(void *p)
{
   stb__span *s;
   if (p == NULL) return;
   s = stb__span_for_page[stb__page_number((stb_uint) p) - stb__firstpage];
   if (s->list >= 256) {
      stb__smemset(p, 0xfe, stb__size_for_class[s->list-256]);
      * (void **) p = s->first_free;
      s->first_free = p;
      if (--s->allocations == 0) {
         stb__spanlist_unlink(s);
         stb__free_span(s);
      }
   } else {
      assert(s->list == 0);
      stb__smemset(p, 0xfe, stb_ssize(p));
      stb__free_span(s);
   }
}

void *stb_srealloc(void *p, size_t sz)
{
   size_t cur_size;
   if (p == NULL) return stb_smalloc(sz);
   if (sz == 0) { stb_sfree(p); return NULL; }
   cur_size = stb_ssize(p);
   if (sz > cur_size || sz <= (cur_size >> 1)) {
      void *q;
      if (sz > cur_size && sz < (cur_size << 1)) sz = cur_size << 1;
      q = stb_smalloc(sz); if (q == NULL) return NULL;
      memcpy(q, p, sz < cur_size ? sz : cur_size);
      stb_sfree(p);
      return q;
   }
   return p;
}

void *stb_scalloc(size_t n, size_t sz)
{
   void *p;
   if (n == 0 || sz == 0) return NULL;
   if (stb_log2_ceil(n) + stb_log2_ceil(n) >= 32) return NULL;
   p = stb_smalloc(n*sz);
   if (p) memset(p, 0, n*sz);
   return p;
}

char *stb_sstrdup(char *s)
{
   int n = strlen(s);
   char *p = (char *) stb_smalloc(n+1);
   if (p) strcpy(p,s);
   return p;
}
#endif // STB_DEFINE



#ifdef STB_STUA
//////////////////////////////////////////////////////////////////////////
//
//  stua: little scripting language
//
//     define STB_STUA to compile it
//
//     see http://nothings.org/stb_stua.html for documentation
//
//  basic parsing model:
//
//   lexical analysis
//      use stb_lex() to parse tokens; keywords get their own tokens
//
//   parsing:
//      recursive descent parser. too much of a hassle to make an unambiguous
//      LR(1) grammar, and one-pass generation is clumsier (recursive descent
//      makes it easier to e.g. compile nested functions). on the other hand,
//      dictionary syntax required hackery to get extra lookahead.
//
//   codegen:
//      output into an evaluation tree, using array indices as 'pointers'
//
//   run:
//      traverse the tree; support for 'break/continue/return' is tricky
//
//   garbage collection:
//      stu__mark and sweep; explicit stack with non-stu__compile_global_scope roots

typedef stb_int32 stua_obj;

typedef stb_idict stua_dict;

STB_EXTERN void stua_run_script(char *s);
STB_EXTERN void stua_uninit(void);

extern stua_obj stua_globals;

STB_EXTERN double   stua_number(stua_obj z);

STB_EXTERN stua_obj stua_getnil(void);
STB_EXTERN stua_obj stua_getfalse(void);
STB_EXTERN stua_obj stua_gettrue(void);
STB_EXTERN stua_obj stua_string(char *z);
STB_EXTERN stua_obj stua_make_number(double d);
STB_EXTERN stua_obj stua_box(int type, void *data, int size);

enum
{
   STUA_op_negate=129,
   STUA_op_shl,   STUA_op_ge,
   STUA_op_shr,   STUA_op_le,
   STUA_op_shru,
   STUA_op_last
};

#define STUA_NO_VALUE   2     // equivalent to a tagged NULL
STB_EXTERN stua_obj (*stua_overload)(int op, stua_obj a, stua_obj b, stua_obj c);

STB_EXTERN stua_obj stua_error(char *err, ...);

STB_EXTERN stua_obj stua_pushroot(stua_obj o);
STB_EXTERN void     stua_poproot (   void   );


#ifdef STB_DEFINE
// INTERPRETER

// 31-bit floating point implementation
//   force the (1 << 30) bit (2nd highest bit) to be zero by re-biasing the exponent;
//   then shift and set the bottom bit

static stua_obj stu__floatp(float *f)
{
   unsigned int n = *(unsigned int *) f;
   unsigned int e = n & (0xff << 23);

   assert(sizeof(int) == 4 && sizeof(float) == 4);

   if (!e)                    // zero?
      n = n;                  //   no change
   else if (e < (64 << 23))   // underflow of the packed encoding?
      n = (n & 0x80000000);   //   signed 0
   else if (e > (190 << 23))  // overflow of the encoding? (or INF or NAN)
      n = (n & 0x80000000) + (127 << 23); // new INF encoding
   else
      n -= 0x20000000;

   // now we need to shuffle the bits so that the spare bit is at the bottom
   assert((n & 0x40000000) == 0);
   return (n & 0x80000000) + (n << 1) + 1;
}

static unsigned char stu__getfloat_addend[256];
static float stu__getfloat(stua_obj v)
{
   unsigned int n;
   unsigned int e = ((unsigned int) v) >> 24;

   n = (int) v >> 1;  // preserve high bit
   n += stu__getfloat_addend[e] << 24;
   return *(float *) &n;
}

stua_obj stua_float(float f) 
{
   return stu__floatp(&f);
}

static void stu__float_init(void)
{
   int i;
   stu__getfloat_addend[0]    = 0;   // do nothing to biased exponent of 0
   for (i=1; i < 127; ++i)
      stu__getfloat_addend[i] = 32;  // undo the -0x20000000
   stu__getfloat_addend[127]  = 64;  // convert packed INF to INF (0x3f -> 0x7f)

   for (i=0; i < 128; ++i) // for signed floats, remove the bit we just shifted down
      stu__getfloat_addend[128+i] = stu__getfloat_addend[i] - 64;
}

// Tagged data type implementation

                                                 // TAGS:
#define stu__int_tag          0  // of 2 bits    //   00   int
#define stu__float_tag        1  // of 1 bit     //   01   float
#define stu__ptr_tag          2  // of 2 bits    //   10   boxed
                                                 //   11   float

#define stu__tag(x)           ((x) & 3)
#define stu__number(x)        (stu__tag(x) != stu__ptr_tag)
#define stu__isint(x)         (stu__tag(x) == stu__int_tag)

#define stu__int(x)           ((x) >> 2)
#define stu__float(x)         (stu__getfloat(x))

#define stu__makeint(v)       ((v)*4+stu__int_tag)

// boxed data, and tag support for boxed data

enum
{
   STU___float    = 1,   STU___int      = 2,
   STU___number   = 3,   STU___string   = 4,
   STU___function = 5,   STU___dict     = 6,
   STU___boolean  = 7,   STU___error    = 8,
};

// boxed data
#define STU__BOX  short type, stua_gc
typedef struct stu__box { STU__BOX; } stu__box;

stu__box stu__nil   = { 0, 1 };
stu__box stu__true  = { STU___boolean, 1, };
stu__box stu__false = { STU___boolean, 1, };

#define stu__makeptr(v)  ((stua_obj)     (v) + stu__ptr_tag)

#define stua_nil    stu__makeptr(&stu__nil)
#define stua_true   stu__makeptr(&stu__true)
#define stua_false  stu__makeptr(&stu__false)

stua_obj stua_getnil(void)   { return stua_nil; }
stua_obj stua_getfalse(void) { return stua_false; }
stua_obj stua_gettrue(void)  { return stua_true; }

#define stu__ptr(x)      ((stu__box *) ((x) - stu__ptr_tag))

#define stu__checkt(t,x) ((t) == STU___float  ? ((x) & 1) == stu__float_tag : \
                          (t) == STU___int    ? stu__isint(x)               : \
                          (t) == STU___number ? stu__number(x)              : \
                          stu__tag(x) == stu__ptr_tag && stu__ptr(x)->type == (t))

typedef struct
{
   STU__BOX;
   void *ptr;
} stu__wrapper;

// implementation of a 'function' or function + closure

typedef struct stu__func
{
   STU__BOX;
   stua_obj closure_source;  // 0 - regular function; 4 - C function
                             // if closure, pointer to source function
   union {
      stua_obj closure_data; // partial-application data
      void *store;           // pointer to free that holds 'code'
      stua_obj (*func)(stua_dict *context);
   } f;
   // closure ends here
   short *code;
   int num_param;
   stua_obj *param;  // list of parameter strings
} stu__func;

// apply this to 'short *code' to get at data
#define stu__const(f)  ((stua_obj *) (f))

static void stu__free_func(stu__func *f)
{
   if (f->closure_source == 0)          free(f->f.store);
   if ((uint) f->closure_source <= 4)   free(f->param);
   free(f);
}

#define stu__pd(x)       ((stua_dict *)    stu__ptr(x))
#define stu__pw(x)       ((stu__wrapper *) stu__ptr(x))
#define stu__pf(x)       ((stu__func *)    stu__ptr(x))


// garbage-collection


static STB__ARR(stu__box *) stu__gc_ptrlist;
static STB__ARR(stua_obj) stu__gc_root_stack;

stua_obj stua_pushroot(stua_obj o) { stb_arr_push(stu__gc_root_stack, o); return o; }
void     stua_poproot (   void   ) { stb_arr_pop(stu__gc_root_stack); }

static stb_sdict *stu__strings;
static void stu__mark(stua_obj z)
{
   int i;
   stu__box *p = stu__ptr(z);
   if (p->stua_gc == 1) return; // already marked
   assert(p->stua_gc == 0);
   p->stua_gc = 1;
   switch(p->type) {
      case STU___function: {
         stu__func *f = (stu__func *) p;
         if ((uint) f->closure_source <= 4) {
            if (f->closure_source == 0) {
               for (i=1; i <= f->code[0]; ++i)
                  if (!stu__number(((stua_obj *) f->code)[-i]))
                     stu__mark(((stua_obj *) f->code)[-i]);
            }
            for (i=0; i < f->num_param; ++i)
               stu__mark(f->param[i]);
         } else {
            stu__mark(f->closure_source);
            stu__mark(f->f.closure_data);
         }
         break;
      }
      case STU___dict: {
         stua_dict *e = (stua_dict *) p;
         for (i=0; i < e->limit; ++i)
            if (e->table[i].k != STB_IEMPTY && e->table[i].k != STB_IDEL) {
               if (!stu__number(e->table[i].k)) stu__mark((int) e->table[i].k);
               if (!stu__number(e->table[i].v)) stu__mark((int) e->table[i].v);
            }
         break;
      }
   }
}

static int stu__num_allocs, stu__size_allocs;
static stua_obj stu__flow_val = stua_nil; // used for break & return

static void stua_gc(int force)
{
   int i;
   if (!force && stu__num_allocs == 0 && stu__size_allocs == 0) return;
   stu__num_allocs = stu__size_allocs = 0;
   //printf("[gc]\n");

   // clear marks
   for (i=0; i < stb_arr_len(stu__gc_ptrlist); ++i)
       stu__gc_ptrlist[i]->stua_gc = 0;

   // stu__mark everything reachable
   stu__nil.stua_gc = stu__true.stua_gc = stu__false.stua_gc = 1;
   stu__mark(stua_globals);
   if (!stu__number(stu__flow_val)) 
      stu__mark(stu__flow_val);
   for (i=0; i < stb_arr_len(stu__gc_root_stack); ++i)
      if (!stu__number(stu__gc_root_stack[i]))
         stu__mark(stu__gc_root_stack[i]);

   // sweep unreachables
   for (i=0; i < stb_arr_len(stu__gc_ptrlist);) {
      stu__box *z = stu__gc_ptrlist[i];         
      if (!z->stua_gc) {
         switch (z->type) {
            case STU___dict:        stb_idict_destroy((stua_dict *) z); break;
            case STU___error:       free(((stu__wrapper *) z)->ptr); break;
            case STU___string:      stb_sdict_remove(stu__strings, (char*) ((stu__wrapper *) z)->ptr, NULL); free(z); break;
            case STU___function:    stu__free_func((stu__func *) z); break;
         }
         // swap in the last item over this, and repeat
         z = stb_arr_pop(stu__gc_ptrlist);
         stu__gc_ptrlist[i] = z;         
      } else
         ++i;
   }
}

static void stu__consider_gc(stua_obj x)
{
   if (stu__size_allocs < 100000) return;
   if (stu__num_allocs < 10 && stu__size_allocs < 1000000) return;
   stb_arr_push(stu__gc_root_stack, x);
   stua_gc(0);
   stb_arr_pop(stu__gc_root_stack);
}

static stua_obj stu__makeobj(int type, void *data, int size, int safe_to_gc)
{
   stua_obj x = stu__makeptr(data);
   ((stu__box *) data)->type = type;
   stb_arr_push(stu__gc_ptrlist, (stu__box *) data);
   stu__num_allocs  += 1;
   stu__size_allocs += size;
   if (safe_to_gc) stu__consider_gc(x);
   return x;
}

stua_obj stua_box(int type, void *data, int size)
{
   stu__wrapper *p = (stu__wrapper *) malloc(sizeof(*p));
   p->ptr = data;
   return stu__makeobj(type, p, size, 0);
}

// a stu string can be directly compared for equality, because
// they go into a hash table
stua_obj stua_string(char *z)
{
   stu__wrapper *b = (stu__wrapper *) stb_sdict_get(stu__strings, z);
   if (b == NULL) {
      int o = stua_box(STU___string, NULL, strlen(z) + sizeof(*b));
      b = stu__pw(o);
      stb_sdict_add(stu__strings, z, b);
      stb_sdict_getkey(stu__strings, z, (char **) &b->ptr);
   }
   return stu__makeptr(b);
}

// stb_obj dictionary is just an stb_idict
static void     stu__set(stua_dict *d, stua_obj k, stua_obj v)
{ if (stb_idict_set(d, k, v)) stu__size_allocs += 8; }

static stua_obj stu__get(stua_dict *d, stua_obj k, stua_obj res)
{
   stb_idict_get_flag(d, k, &res);
   return res;
}

static stua_obj make_string(char *z, int len)
{
   stua_obj s;
   char temp[256], *q = (char *) stb_temp(temp, len+1), *p = q;
   while (len > 0) {
      if (*z == '\\') {
              if (z[1] == 'n') *p = '\n';
         else if (z[1] == 'r') *p = '\r';
         else if (z[1] == 't') *p = '\t';
         else                  *p = z[1];
         p += 1; z += 2; len -= 2;
      } else {
         *p++ = *z++; len -= 1;
      }
   }
   *p = 0;
   s = stua_string(q);
   stb_tempfree(temp, q);
   return s;
}

enum token_names
{
   T__none=128,
   ST_shl = STUA_op_shl,    ST_ge  = STUA_op_ge,
   ST_shr = STUA_op_shr,    ST_le = STUA_op_le,
   ST_shru = STUA_op_shru,  STU__negate = STUA_op_negate,
   ST__reset_numbering = STUA_op_last,
   ST_white,
   ST_id, ST_float, ST_decimal, ST_hex, ST_char,ST_string, ST_number,
   // make sure the keywords come _AFTER_ ST_id, so stb_lex prefer them
   ST_if,      ST_while,    ST_for,     ST_eq,  ST_nil,
   ST_then,    ST_do,       ST_in,      ST_ne,  ST_true,
   ST_else,    ST_break,    ST_let,     ST_and, ST_false,
   ST_elseif,  ST_continue, ST_into,    ST_or,  ST_repeat,
   ST_end,     ST_as,       ST_return,  ST_var, ST_func,
   ST_catch,   ST__frame,
   ST__max_terminals,

   STU__defaultparm, STU__seq,
};

static stua_dict  * stu__globaldict;
       stua_obj     stua_globals;

static enum
{
   FLOW_normal,  FLOW_continue,   FLOW_break,  FLOW_return,  FLOW_error,
} stu__flow;

stua_obj stua_error(char *z, ...)
{
   stua_obj a;
   char temp[4096], *x;
   va_list v; va_start(v,z); vsprintf(temp, z, v); va_end(v);
   x = strdup(temp);
   a = stua_box(STU___error, x, strlen(x));
   stu__flow = FLOW_error;
   stu__flow_val = a;
   return stua_nil;
}

double stua_number(stua_obj z)
{
   return stu__tag(z) == stu__int_tag ? stu__int(z) : stu__float(z);
}

stua_obj stua_make_number(double d)
{
   double e = floor(d);
   if (e == d && e < (1 << 29) && e >= -(1 << 29))
      return stu__makeint((int) e);
   else
      return stua_float((float) d);
}

stua_obj (*stua_overload)(int op, stua_obj a, stua_obj b, stua_obj c) = NULL;

static stua_obj stu__op(int op, stua_obj a, stua_obj b, stua_obj c)
{
   stua_obj r = STUA_NO_VALUE;
   if (op == '+') {
      if (stu__checkt(STU___string, a) && stu__checkt(STU___string, b)) {
         ;// @TODO: string concatenation
      } else if (stu__checkt(STU___function, a) && stu__checkt(STU___dict, b)) {
         stu__func *f = (stu__func *) malloc(12);
         assert(offsetof(stu__func, code)==12);
         f->closure_source = a;
         f->f.closure_data = b;
         return stu__makeobj(STU___function, f, 16, 1);
      }
   }
   if (stua_overload) r = stua_overload(op,a,b,c);
   if (stu__flow != FLOW_error && r == STUA_NO_VALUE)
      stua_error("Typecheck for operator %d", op), r=stua_nil;
   return r;
}

#define STU__EVAL2(a,b)             \
          a = stu__eval(stu__f[n+1]);  if (stu__flow) break; stua_pushroot(a); \
          b = stu__eval(stu__f[n+2]);  stua_poproot(); if (stu__flow) break;

#define STU__FB(op)              \
          STU__EVAL2(a,b)           \
          if (stu__tag(a) == stu__int_tag && stu__tag(b) == stu__int_tag) \
             return ((a) op (b));                 \
          if (stu__number(a) && stu__number(b)) \
             return stua_make_number(stua_number(a) op stua_number(b)); \
          return stu__op(stu__f[n], a,b, stua_nil)

#define STU__F(op)              \
          STU__EVAL2(a,b)           \
          if (stu__number(a) && stu__number(b)) \
             return stua_make_number(stua_number(a) op stua_number(b)); \
          return stu__op(stu__f[n], a,b, stua_nil)

#define STU__I(op)               \
          STU__EVAL2(a,b)           \
          if (stu__tag(a) == stu__int_tag && stu__tag(b) == stu__int_tag) \
             return stu__makeint(stu__int(a) op stu__int(b));                 \
          return stu__op(stu__f[n], a,b, stua_nil)

#define STU__C(op)               \
          STU__EVAL2(a,b)           \
          if (stu__number(a) && stu__number(b)) \
             return (stua_number(a) op stua_number(b)) ? stua_true : stua_false; \
          return stu__op(stu__f[n], a,b, stua_nil)

#define STU__CE(op)              \
          STU__EVAL2(a,b)           \
          return (a op b) ? stua_true : stua_false

static short *stu__f;
static stua_obj  stu__f_obj;
static stua_dict       *stu__c;
static stua_obj stu__funceval(stua_obj fo, stua_obj co);

static int stu__cond(stua_obj x)
{
   if (stu__flow) return 0;
   if (!stu__checkt(STU___boolean, x))
      x = stu__op('!', x, stua_nil, stua_nil);
   if (x == stua_true ) return 1;
   if (x == stua_false) return 0;
   stu__flow = FLOW_error;
   return 0;
}

// had to manually eliminate tailcall recursion for debugging complex stuff
#define TAILCALL(x)   n = (x); goto top;
static stua_obj stu__eval(int n)
{
top:
   if (stu__flow >= FLOW_return) return stua_nil; // is this needed?
   if (n < 0) return stu__const(stu__f)[n];
   assert(n != 0 && n != 1);
   switch (stu__f[n]) {
      stua_obj a,b,c;
      case ST_catch:   a = stu__eval(stu__f[n+1]);
                       if (stu__flow == FLOW_error) { a=stu__flow_val; stu__flow = FLOW_normal; }
                       return a;
      case ST_var:     b = stu__eval(stu__f[n+2]); if (stu__flow) break;
                       stu__set(stu__c, stu__const(stu__f)[stu__f[n+1]], b);
                       return b;
      case STU__seq:   stu__eval(stu__f[n+1]); if (stu__flow) break;
                       TAILCALL(stu__f[n+2]);
      case ST_if:      if (!stu__cond(stu__eval(stu__f[n+1]))) return stua_nil;
                       TAILCALL(stu__f[n+2]);
      case ST_else:    a = stu__cond(stu__eval(stu__f[n+1]));
                       TAILCALL(stu__f[n + 2 + !a]);
                       #define STU__HANDLE_BREAK            \
                          if (stu__flow >= FLOW_break) {    \
                             if (stu__flow == FLOW_break) { \
                                a = stu__flow_val;          \
                                stu__flow = FLOW_normal;    \
                                stu__flow_val = stua_nil;   \
                                return a;                   \
                             }                              \
                             return stua_nil;               \
                          }
      case ST_as:      stu__eval(stu__f[n+3]);
                       STU__HANDLE_BREAK
                       // fallthrough!
      case ST_while:   a = stua_nil; stua_pushroot(a);
                       while (stu__cond(stu__eval(stu__f[n+1]))) {
                          stua_poproot();
                          a = stu__eval(stu__f[n+2]);
                          STU__HANDLE_BREAK
                          stu__flow = FLOW_normal;  // clear 'continue' flag
                          stua_pushroot(a);
                          if (stu__f[n+3]) stu__eval(stu__f[n+3]);
                          STU__HANDLE_BREAK
                          stu__flow = FLOW_normal;  // clear 'continue' flag
                       }
                       stua_poproot();
                       return a;
      case ST_break:   stu__flow = FLOW_break;  stu__flow_val = stu__eval(stu__f[n+1]); break;
      case ST_continue:stu__flow = FLOW_continue; break;
      case ST_return:  stu__flow = FLOW_return; stu__flow_val = stu__eval(stu__f[n+1]); break;
      case ST__frame:  return stu__f_obj;
      case '[':        STU__EVAL2(a,b);
                       if (stu__checkt(STU___dict, a))
                          return stu__get(stu__pd(a), b, stua_nil);
                       return stu__op(stu__f[n], a, b, stua_nil);
      case '=':        a = stu__eval(stu__f[n+2]); if (stu__flow) break;
                       n = stu__f[n+1];
                       if (stu__f[n] == ST_id) {
                          if (!stb_idict_update(stu__c, stu__const(stu__f)[stu__f[n+1]], a))
                             if (!stb_idict_update(stu__globaldict, stu__const(stu__f)[stu__f[n+1]], a))
                                return stua_error("Assignment to undefined variable");
                       } else if (stu__f[n] == '[') {
                          stua_pushroot(a);
                          b = stu__eval(stu__f[n+1]); if (stu__flow) { stua_poproot(); break; }
                          stua_pushroot(b);
                          c = stu__eval(stu__f[n+2]); stua_poproot(); stua_poproot();
                          if (stu__flow) break;
                          if (!stu__checkt(STU___dict, b)) return stua_nil;
                          stu__set(stu__pd(b), c, a);
                       } else {
                          return stu__op(stu__f[n], stu__eval(n), a, stua_nil);
                       }
                       return a;
      case STU__defaultparm:
                       a = stu__eval(stu__f[n+2]);
                       stu__flow = FLOW_normal;
                       if (stb_idict_add(stu__c, stu__const(stu__f)[stu__f[n+1]], a))
                          stu__size_allocs += 8;
                       return stua_nil;
      case ST_id:      a = stu__get(stu__c, stu__const(stu__f)[stu__f[n+1]], STUA_NO_VALUE); // try local variable
                       return a != STUA_NO_VALUE       // else try stu__compile_global_scope variable
                            ? a : stu__get(stu__globaldict, stu__const(stu__f)[stu__f[n+1]], stua_nil);
      case STU__negate:a = stu__eval(stu__f[n+1]); if (stu__flow) break;
                       return stu__isint(a) ? -a : stu__op(stu__f[n], a, stua_nil, stua_nil);
      case '~':        a = stu__eval(stu__f[n+1]); if (stu__flow) break;
                       return stu__isint(a) ? (~a)&~3 : stu__op(stu__f[n], a, stua_nil, stua_nil);
      case '!':        a = stu__eval(stu__f[n+1]); if (stu__flow) break;
                       a = stu__cond(a); if (stu__flow) break;
                       return a ? stua_true : stua_false;
      case ST_eq: STU__CE(==); case ST_le: STU__C(<=); case '<': STU__C(<);
      case ST_ne: STU__CE(!=); case ST_ge: STU__C(>=); case '>': STU__C(>);
      case '+' : STU__FB(+);  case '*': STU__F(*);  case '&': STU__I(&); case ST_shl: STU__I(<<);
      case '-' : STU__FB(-);  case '/': STU__F(/);  case '|': STU__I(|); case ST_shr: STU__I(>>);
                             case '%': STU__I(%);  case '^': STU__I(^);
      case ST_shru:    STU__EVAL2(a,b);
                       if (stu__tag(a) == stu__int_tag && stu__tag(b) == stu__int_tag)
                          return stu__makeint((unsigned) stu__int(a) >> stu__int(b));
                       return stu__op(stu__f[n], a,b, stua_nil);
      case ST_and:      a = stu__eval(stu__f[n+1]); b = stu__cond(a); if (stu__flow) break;
                       return a ? stu__eval(stu__f[n+2]) : a;
      case ST_or :      a = stu__eval(stu__f[n+1]); b = stu__cond(a); if (stu__flow) break;
                       return a ? b : stu__eval(stu__f[n+2]);
      case'(':case':': STU__EVAL2(a,b);
                       if (!stu__checkt(STU___function, a))
                           return stu__op(stu__f[n], a,b, stua_nil);
                       if (!stu__checkt(STU___dict, b))
                           return stua_nil;
                       if (stu__f[n] == ':')
                          b = stu__makeobj(STU___dict, stb_idict_copy(stu__pd(b)), stb_idict_memory_usage(stu__pd(b)), 0);
                       a = stu__funceval(a,b);
                       return a;
      case '{' :    {
                       stua_dict *d;
                       d = stb_idict_new_size(stu__f[n+1] > 40 ? 64 : 16);
                       if (d == NULL)
                          return stua_nil; // breakpoint fodder
                       c = stu__makeobj(STU___dict, d, 32, 1);
                       stua_pushroot(c);
                       a = stu__f[n+1];
                       for (b=0; b < a; ++b) {
                          stua_obj x = stua_pushroot(stu__eval(stu__f[n+2 + b*2 + 0]));
                          stua_obj y = stu__eval(stu__f[n+2 + b*2 + 1]);
                          stua_poproot();
                          if (stu__flow) { stua_poproot(); return stua_nil; }
                          stu__set(d, x, y);
                       }
                       stua_poproot();
                       return c;
                    }
      default:         if (stu__f[n] < 0) return stu__const(stu__f)[stu__f[n]];
                       assert(0); /* NOTREACHED */ // internal error!
   }
   return stua_nil;
}

int stb__stua_nesting;
static stua_obj stu__funceval(stua_obj fo, stua_obj co)
{
   stu__func *f = stu__pf(fo);
   stua_dict *context = stu__pd(co);
   int i,j;
   stua_obj p;
   short *tf = stu__f;     // save previous function
   stua_dict *tc = stu__c;

   if (stu__flow == FLOW_error) return stua_nil;
   assert(stu__flow == FLOW_normal);

   stua_pushroot(fo);
   stua_pushroot(co);
   stu__consider_gc(stua_nil);

   while ((uint) f->closure_source > 4) {
      // add data from closure to context
      stua_dict *e = (stua_dict *) stu__pd(f->f.closure_data);
      for (i=0; i < e->limit; ++i)
         if (e->table[i].k != STB_IEMPTY && e->table[i].k != STB_IDEL)
            if (stb_idict_add(context, e->table[i].k, e->table[i].v))
               stu__size_allocs += 8;
            // use add so if it's already defined, we don't override it; that way
            // explicit parameters win over applied ones, and most recent applications
            // win over previous ones
      f = stu__pf(f->closure_source);
   }

   for (j=0, i=0; i < f->num_param; ++i)
      // if it doesn't already exist, add it from the numbered parameters
      if (stb_idict_add(context, f->param[i], stu__get(context, stu__int(j), stua_nil)))
         ++j;

   // @TODO: if (stu__get(context, stu__int(f->num_param+1)) != STUA_NO_VALUE) // error: too many parameters
   // @TODO: ditto too few parameters

   if (f->closure_source == 4)
      p = f->f.func(context);
   else {
      stu__f = f->code, stu__c = context;
      stu__f_obj = co;
      ++stb__stua_nesting;
      if (stu__f[1]) 
         p = stu__eval(stu__f[1]);
      else
         p = stua_nil;
      --stb__stua_nesting;
      stu__f = tf, stu__c = tc;  // restore previous function
      if (stu__flow == FLOW_return) {
         stu__flow = FLOW_normal;
         p = stu__flow_val;
         stu__flow_val = stua_nil;
      }
   }

   stua_poproot();
   stua_poproot();

   return p;
}

// Parser

static int stu__tok;
static stua_obj stu__tokval;

static char *stu__curbuf, *stu__bufstart;

static stb_matcher *stu__lex_matcher;

static unsigned char stu__prec[ST__max_terminals], stu__end[ST__max_terminals];

static void stu__nexttoken(void)
{
   int len;

retry:
   stu__tok = stb_lex(stu__lex_matcher, stu__curbuf, &len);
   if (stu__tok == 0)
      return;
   switch(stu__tok) {
      case ST_white  : stu__curbuf += len; goto retry;
      case T__none  : stu__tok = *stu__curbuf; break;
      case ST_string:  stu__tokval = make_string(stu__curbuf+1, len-2); break;
      case ST_id    :  stu__tokval = make_string(stu__curbuf, len); break;
      case ST_hex    : stu__tokval = stu__makeint(strtol(stu__curbuf+2,NULL,16)); stu__tok = ST_number; break;
      case ST_decimal: stu__tokval = stu__makeint(strtol(stu__curbuf  ,NULL,10)); stu__tok = ST_number; break;
      case ST_float  : stu__tokval = stua_float((float) atof(stu__curbuf))       ; stu__tok = ST_number; break;
      case ST_char   : stu__tokval = stu__curbuf[2] == '\\' ? stu__curbuf[3] : stu__curbuf[2];
                      if (stu__curbuf[3] == 't') stu__tokval = '\t';
                      if (stu__curbuf[3] == 'n') stu__tokval = '\n';
                      if (stu__curbuf[3] == 'r') stu__tokval = '\r';
                      stu__tokval = stu__makeint(stu__tokval);
                      stu__tok  = ST_number;
                      break;
   }
   stu__curbuf += len;
}

static struct { int stu__tok; char *regex; } stu__lexemes[] =
{
   ST_white  , "([ \t\n\r]|/\\*(.|\n)*\\*/|//[^\r\n]*([\r\n]|$))+",
   ST_id     , "[_a-zA-Z][_a-zA-Z0-9]*",
   ST_hex    , "0x[0-9a-fA-F]+",
   ST_decimal, "[0-9]+[0-9]*",
   ST_float  , "[0-9]+\\.?[0-9]*([eE][-+]?[0-9]+)?",
   ST_float  , "\\.[0-9]+([eE][-+]?[0-9]+)?",
   ST_char   , "c'(\\\\.|[^\\'])'",
   ST_string , "\"(\\\\.|[^\\\"\n\r])*\"",
   ST_string , "\'(\\\\.|[^\\\'\n\r])*\'",

   #define stua_key4(a,b,c,d)  ST_##a, #a, ST_##b, #b, ST_##c, #c, ST_##d, #d,
   stua_key4(if,then,else,elseif)    stua_key4(while,do,for,in)
   stua_key4(func,var,let,break)     stua_key4(nil,true,false,end)
   stua_key4(return,continue,as,repeat) stua_key4(_frame,catch,catch,catch)

   ST_shl, "<<",   ST_and, "&&",  ST_eq,  "==",  ST_ge, ">=", 
   ST_shr, ">>",   ST_or , "||",  ST_ne,  "!=",  ST_le, "<=",
   ST_shru,">>>",  ST_into, "=>",
   T__none, ".",
};

typedef struct
{
   STB__ARR(stua_obj) data;    // constants being compiled
   STB__ARR(short)    code;    // code being compiled
   stua_dict         *locals;
   STB__ARR(short)    non_local_refs;
} stu__comp_func;

static stu__comp_func stu__pfunc;
static STB__ARR(stu__comp_func) func_stack = NULL;
static void stu__push_func_comp(void)
{
   stb_arr_push(func_stack, stu__pfunc);
   stu__pfunc.data = NULL;
   stu__pfunc.code = NULL;
   stu__pfunc.locals = stb_idict_new_size(16);
   stu__pfunc.non_local_refs = NULL;
   stb_arr_push(stu__pfunc.code, 0); // number of data items
   stb_arr_push(stu__pfunc.code, 1); // starting execution address
}

static void stu__pop_func_comp(void)
{
   stb_arr_free(stu__pfunc.code);
   stb_arr_free(stu__pfunc.data);   
   stb_idict_destroy(stu__pfunc.locals);
   stb_arr_free(stu__pfunc.non_local_refs);
   stu__pfunc = stb_arr_pop(func_stack);
}

// if an id is a reference to an outer lexical scope, this
// function returns the "name" of it, and updates the stack
// structures to make sure the names are propogated in.
static int stu__nonlocal_id(stua_obj var_obj)
{
   stua_obj dummy, var = var_obj;
   int i, n = stb_arr_len(func_stack), j,k;
   if (stb_idict_get_flag(stu__pfunc.locals, var, &dummy)) return 0;
   for (i=n-1; i > 1; --i) {
      if (stb_idict_get_flag(func_stack[i].locals, var, &dummy))
         break;
   }
   if (i <= 1) return 0; // stu__compile_global_scope
   j = i; // need to access variable from j'th frame
   for (i=0; i < stb_arr_len(stu__pfunc.non_local_refs); ++i)
      if (stu__pfunc.non_local_refs[i] == j) return j-n;
   stb_arr_push(stu__pfunc.non_local_refs, j-n);
   // now make sure all the parents propogate it down
   for (k=n-1; k > 1; --k) {
      if (j-k >= 0) return j-n; // comes direct from this parent
      for(i=0; i < stb_arr_len(func_stack[k].non_local_refs); ++i)
         if (func_stack[k].non_local_refs[i] == j-k)
            return j-n;
      stb_arr_push(func_stack[k].non_local_refs, j-k);
   }
   assert (k != 1);

   return j-n;
}

static int stu__off(void)                { return stb_arr_len(stu__pfunc.code); }
static void stu__cc(int a)
{
   assert(a >= -2000 && a < 5000);
   stb_arr_push(stu__pfunc.code, a);
}
static int stu__cc1(int a)                      { stu__cc(a); return stu__off()-1; }
static int stu__cc2(int a, int b)               { stu__cc(a); stu__cc(b); return stu__off()-2; }
static int stu__cc3(int a, int b, int c)        {
 if (a == '=') assert(c != 0);
 stu__cc(a); stu__cc(b); stu__cc(c); return stu__off()-3; }
static int stu__cc4(int a, int b, int c, int d) { stu__cc(a); stu__cc(b); stu__cc(c); stu__cc(d); return stu__off()-4; }

static int stu__cdv(stua_obj p)
{
   int i;
   assert(p != STUA_NO_VALUE);
   for (i=0; i < stb_arr_len(stu__pfunc.data); ++i)
      if (stu__pfunc.data[i] == p)
         break;
   if (i == stb_arr_len(stu__pfunc.data))
      stb_arr_push(stu__pfunc.data, p);
   return ~i;
}

static int stu__cdt(void)
{
   int z = stu__cdv(stu__tokval);
   stu__nexttoken();
   return z;
}

static int stu__seq(int a, int b)
{
   return !a ? b : !b ? a : stu__cc3(STU__seq, a,b);
}

static char stu__comp_err_str[1024];
static int stu__comp_err_line;
static int stu__err(char *str, ...)
{
   va_list v;
   char *s = stu__bufstart;
   stu__comp_err_line = 1;
   while (s < stu__curbuf) {
      if (s[0] == '\n' || s[0] == '\r') {
         if (s[0]+s[1] == '\n' + '\r') ++s;
         ++stu__comp_err_line;
      }
      ++s;
   }
   va_start(v, str);
   vsprintf(stu__comp_err_str, str, v);
   va_end(v);
   return 0;
}

static int stu__accept(int p)
{
   if (stu__tok != p) return 0;
   stu__nexttoken();
   return 1;
}

static int stu__demand(int p)
{
   if (stu__accept(p)) return 1;
   return stu__err("Didn't find expected stu__tok");
}

static int stu__demandv(int p, stua_obj *val)
{
   if (stu__tok == p || p==0) {
      *val = stu__tokval;
      stu__nexttoken();
      return 1;
   } else
      return 0;
}

static int stu__expr(int p);
int stu__nexpr(int p) { stu__nexttoken(); return stu__expr(p); }
static int stu__statements(int once, int as);

static int stu__parse_if(void)      // parse both ST_if and ST_elseif
{
   int b,c,a;
   a = stu__nexpr(1);               if (!a) return 0;
   if (!stu__demand(ST_then))       return stu__err("expecting THEN");
   b = stu__statements(0,0);        if (!b) return 0;
   if (b == 1) b = -1;

   if (stu__tok == ST_elseif) {
      return stu__parse_if();
   } else if (stu__accept(ST_else)) {
      c = stu__statements(0,0); if (!c) return 0;
      if (!stu__demand(ST_end)) return stu__err("expecting END after else clause");
      return stu__cc4(ST_else, a, b, c);
   } else {
      if (!stu__demand(ST_end)) return stu__err("expecting END in if statement");
      return stu__cc3(ST_if, a, b);
   }
}

int stu__varinit(int z, int in_globals)
{
   int a,b;
   stu__nexttoken();
   while (stu__demandv(ST_id, &b)) {
      if (!stb_idict_add(stu__pfunc.locals, b, 1))
         if (!in_globals) return stu__err("Redefined variable %s.", stu__pw(b)->ptr);
      if (stu__accept('=')) {
         a = stu__expr(1);       if (!a) return 0;
      } else
         a = stu__cdv(stua_nil);
      z = stu__seq(z, stu__cc3(ST_var, stu__cdv(b), a));
      if (!stu__accept(',')) break;
   }
   return z;
}

static int stu__compile_unary(int z, int outparm, int require_inparm)
{
   int op = stu__tok, a, b;
   stu__nexttoken();
   if (outparm) {
      if (require_inparm || (stu__tok && stu__tok != ST_end && stu__tok != ST_else && stu__tok != ST_elseif && stu__tok !=';')) {
         a = stu__expr(1); if (!a) return 0;
      } else
         a = stu__cdv(stua_nil);
      b = stu__cc2(op, a);
   } else
      b = stu__cc1(op);
   return stu__seq(z,b);
}

static int stu__assign(void)
{
   int z;
   stu__accept(ST_let);
   z = stu__expr(1); if (!z) return 0;
   if (stu__accept('=')) {
      int y,p = (z >= 0 ? stu__pfunc.code[z] : 0);
      if (z < 0 || (p != ST_id && p != '[')) return stu__err("Invalid lvalue in assignment");
      y = stu__assign();         if (!y) return 0;
      z = stu__cc3('=', z, y);
   }
   return z;
}

static int stu__statements(int once, int stop_while)
{
   int a,b, c, z=0;
   for(;;) {
      switch (stu__tok) {
         case ST_if     : a = stu__parse_if(); if (!a) return 0;
                          z = stu__seq(z, a);
                          break;
         case ST_while  : if (stop_while) return (z ? z:1);
                          a = stu__nexpr(1); if (!a) return 0;
                          if (stu__accept(ST_as)) c = stu__statements(0,0); else c = 0;
                          if (!stu__demand(ST_do)) return stu__err("expecting DO");
                          b = stu__statements(0,0); if (!b) return 0;
                          if (!stu__demand(ST_end)) return stu__err("expecting END");
                          if (b == 1) b = -1;
                          z = stu__seq(z, stu__cc4(ST_while, a, b, c));
                          break;
         case ST_repeat : stu__nexttoken();
                          c = stu__statements(0,1); if (!c) return 0;
                          if (!stu__demand(ST_while)) return stu__err("expecting WHILE");
                          a = stu__expr(1); if (!a) return 0;
                          if (!stu__demand(ST_do)) return stu__err("expecting DO");
                          b = stu__statements(0,0); if (!b) return 0;
                          if (!stu__demand(ST_end)) return stu__err("expecting END");
                          if (b == 1) b = -1;
                          z = stu__seq(z, stu__cc4(ST_as, a, b, c));
                          break;
         case ST_catch  : a = stu__nexpr(1); if (!a) return 0;
                          z = stu__seq(z, stu__cc2(ST_catch, a));
                          break;
         case ST_var    : z = stu__varinit(z,0); break;
         case ST_return : z = stu__compile_unary(z,1,1); break;
         case ST_continue:z = stu__compile_unary(z,0,0); break;
         case ST_break  : z = stu__compile_unary(z,1,0); break;
         case ST_into   : if (z == 0 && !once) return stu__err("=> cannot be first statement in block");
                          a = stu__nexpr(99);
                          b = (a >= 0? stu__pfunc.code[a] : 0);
                          if (a < 0 || (b != ST_id && b != '[')) return stu__err("Invalid lvalue on right side of =>");
                          z = stu__cc3('=', a, z);
                          break;
         default        : if (stu__end[stu__tok]) return once ? 0 : (z ? z:1);
                          a = stu__assign(); if (!a) return 0;
                          stu__accept(';');
                          if (stu__tok && !stu__end[stu__tok]) {
                             if (a < 0)
                                return stu__err("Constant has no effect");
                             if (stu__pfunc.code[a] != '(' && stu__pfunc.code[a] != '=')
                                return stu__err("Expression has no effect");
                          }
                          z = stu__seq(z, a);
                          break;
      }
      if (!z) return 0;
      stu__accept(';');
      if (once && stu__tok != ST_into) return z;
   }
}

static int stu__postexpr(int z, int p);
static int stu__dictdef(int end, int *count)
{
   int z,n=0,i,flags=0;
   STB__ARR(short) dict=NULL;
   stu__nexttoken();
   while (stu__tok != end) {
      if (stu__tok == ST_id) {
         stua_obj id = stu__tokval;
         stu__nexttoken();
         if (stu__tok == '=') {
            flags |= 1;
            stb_arr_push(dict, stu__cdv(id));
            z = stu__nexpr(1); if (!z) return 0;
         } else {
            z = stu__cc2(ST_id, stu__cdv(id));
            z = stu__postexpr(z,1); if (!z) return 0;
            flags |= 2;
            stb_arr_push(dict, stu__cdv(stu__makeint(n++)));
         }
      } else {
         z = stu__expr(1); if (!z) return 0;
         flags |= 2;
         stb_arr_push(dict, stu__cdv(stu__makeint(n++)));
      }
      if (end != ')' && flags == 3) { z=stu__err("can't mix initialized and uninitialized defs"); goto done;}
      stb_arr_push(dict, z);
      if (!stu__accept(',')) break;
   }
   if (!stu__demand(end))
      return stu__err(end == ')' ? "Expecting ) at end of function call" 
                                 : "Expecting } at end of dictionary definition");
   z = stu__cc2('{', stb_arr_len(dict)/2);
   for (i=0; i < stb_arr_len(dict); ++i)
      stu__cc(dict[i]);
   if (count) *count = n;
done:
   stb_arr_free(dict);
   return z;
}

static int stu__comp_id(void)
{
   int z,d;
   d = stu__nonlocal_id(stu__tokval);
   if (d == 0)
      return z = stu__cc2(ST_id, stu__cdt());
   // access a non-local frame by naming it with the appropriate int
   assert(d < 0);
   z = stu__cdv(d);            // relative frame # is the 'variable' in our local frame
   z = stu__cc2(ST_id, z);     // now access that dictionary
   return stu__cc3('[', z, stu__cdt()); // now access the variable from that dir
}

static stua_obj stu__funcdef(stua_obj *id, stua_obj *func);
static int stu__expr(int p)
{
   int z;
   // unary
   switch (stu__tok) {
      case ST_number: z = stu__cdt(); break;
      case ST_string: z = stu__cdt(); break;  // @TODO - string concatenation like C
      case ST_id    : z = stu__comp_id(); break;
      case ST__frame: z = stu__cc1(ST__frame); stu__nexttoken(); break;
      case ST_func  : z = stu__funcdef(NULL,NULL); break;
      case ST_if    : z = stu__parse_if(); break;
      case ST_nil   : z = stu__cdv(stua_nil); stu__nexttoken(); break;
      case ST_true  : z = stu__cdv(stua_true); stu__nexttoken(); break;
      case ST_false : z = stu__cdv(stua_false); stu__nexttoken(); break;
      case '-'      : z = stu__nexpr(99); if (z) z=stu__cc2(STU__negate,z); else return z; break;
      case '!'      : z = stu__nexpr(99); if (z) z=stu__cc2('!',z); else return z; break;
      case '~'      : z = stu__nexpr(99); if (z) z=stu__cc2('~',z); else return z; break;
      case '{'      : z = stu__dictdef('}', NULL); break;
      default       : return stu__err("Unexpected token");
      case '('      : stu__nexttoken(); z = stu__statements(0,0); if (!stu__demand(')')) return stu__err("Expecting )");
   }
   return stu__postexpr(z,p);
}

static int stu__postexpr(int z, int p)
{
   int q;
   // postfix
   while (stu__tok == '(' || stu__tok == '[' || stu__tok == '.') {
      if (stu__accept('.')) {
         // MUST be followed by a plain identifier! use [] for other stuff
         if (stu__tok != ST_id) return stu__err("Must follow . with plain name; try [] instead");
         z = stu__cc3('[', z, stu__cdv(stu__tokval));
         stu__nexttoken();
      } else if (stu__accept('[')) {
         while (stu__tok != ']') {
            int r = stu__expr(1); if (!r) return 0;
            z = stu__cc3('[', z, r);
            if (!stu__accept(',')) break;
         }
         if (!stu__demand(']')) return stu__err("Expecting ]");
      } else {
         int n, p = stu__dictdef(')', &n); if (!p) return 0;
         #if 0 // this is incorrect!
         if (z > 0 && stu__pfunc.code[z] == ST_id) {
            stua_obj q = stu__get(stu__globaldict, stu__pfunc.data[-stu__pfunc.code[z+1]-1], stua_nil);
            if (stu__checkt(STU___function, q))
               if ((stu__pf(q))->num_param != n)
                  return stu__err("Incorrect number of parameters");
         }
         #endif
         z = stu__cc3('(', z, p);
      }
   }
   // binop - this implementation taken from lcc
   for (q=stu__prec[stu__tok]; q >= p; --q) {
      while (stu__prec[stu__tok] == q) {
         int o = stu__tok, y = stu__nexpr(p+1); if (!y) return 0;
         z = stu__cc3(o,z,y);
      }
   }
   return z;
}

static stua_obj stu__finish_func(STB__ARR(stua_obj) param, int start)
{
   int n, size;
   stu__func *f = (stu__func *) malloc(sizeof(*f));
   f->closure_source = 0;
   f->num_param = stb_arr_len(param);
   f->param = (int *) stb_copy(param, f->num_param * sizeof(*f->param));
   size = stb_arr_storage(stu__pfunc.code) + stb_arr_storage(stu__pfunc.data) + sizeof(*f) + 8;
   f->f.store = malloc(stb_arr_storage(stu__pfunc.code) + stb_arr_storage(stu__pfunc.data));
   f->code = (short *) ((char *) f->f.store + stb_arr_storage(stu__pfunc.data));
   memcpy(f->code, stu__pfunc.code, stb_arr_storage(stu__pfunc.code));
   f->code[1] = start;
   f->code[0] = stb_arr_len(stu__pfunc.data);
   for (n=0; n < f->code[0]; ++n)
      ((stua_obj *) f->code)[-1-n] = stu__pfunc.data[n];
   return stu__makeobj(STU___function, f, size, 0);
}

static int stu__funcdef(stua_obj *id, stua_obj *result)
{
   int n,z=0,i,q;
   STB__ARR(stua_obj) param = NULL;
   STB__ARR(short) nonlocal;
   stua_obj v,f=stua_nil;
   assert(stu__tok == ST_func);
   stu__nexttoken();
   if (id) { 
      if (!stu__demandv(ST_id, id)) return stu__err("Expecting function name");
   } else
      stu__accept(ST_id);
   if (!stu__demand('(')) return stu__err("Expecting ( for function parameter");
   stu__push_func_comp();
   while (stu__tok != ')') {
      if (!stu__demandv(ST_id, &v)) { z=stu__err("Expecting parameter name"); goto done; }
      stb_idict_add(stu__pfunc.locals, v, 1);
      if (stu__tok == '=') {
         n = stu__nexpr(1); if (!n) { z=0; goto done; }
         z = stu__seq(z, stu__cc3(STU__defaultparm, stu__cdv(v), n));
      } else
         stb_arr_push(param, v);
      if (!stu__accept(',')) break;
   }
   if (!stu__demand(')'))   { z=stu__err("Expecting ) at end of parameter list"); goto done; }
   n = stu__statements(0,0);   if (!n) { z=0; goto done; }
   if (!stu__demand(ST_end)) { z=stu__err("Expecting END at end of function"); goto done; }
   if (n == 1) n = 0;
   n = stu__seq(z,n);
   f = stu__finish_func(param, n);
   if (result) { *result = f; z=1; stu__pop_func_comp(); }
   else {
      nonlocal = stu__pfunc.non_local_refs;
      stu__pfunc.non_local_refs = NULL;
      stu__pop_func_comp();
      z = stu__cdv(f);
      if (nonlocal) {  // build a closure with references to the needed frames
         STB__ARR(short) initcode = NULL;
         for (i=0; i < stb_arr_len(nonlocal); ++i) {
            int k = nonlocal[i], p;
            stb_arr_push(initcode, stu__cdv(k));
            if (k == -1) p = stu__cc1(ST__frame);
            else { p = stu__cdv(stu__makeint(k+1)); p = stu__cc2(ST_id, p); }
            stb_arr_push(initcode, p);
         }
         q = stu__cc2('{', stb_arr_len(nonlocal));
         for (i=0; i < stb_arr_len(initcode); ++i)
            stu__cc(initcode[i]);
         z = stu__cc3('+', z, q);
         stb_arr_free(initcode);
      }
      stb_arr_free(nonlocal);
   }
done:
   stb_arr_free(param);
   if (!z) stu__pop_func_comp();
   return z;
}

static int stu__compile_global_scope(void)
{
   stua_obj o;
   int z=0;

   stu__push_func_comp();
   while (stu__tok != 0) {
      if (stu__tok == ST_func) {
         stua_obj id, f;
         if (!stu__funcdef(&id,&f))
            goto error;
         stu__set(stu__globaldict, id, f);
      } else if (stu__tok == ST_var) {
         z = stu__varinit(z,1); if (!z) goto error;
      } else {
         int y = stu__statements(1,0); if (!y) goto error;
         z = stu__seq(z,y);
      }
      stu__accept(';');
   }
   o = stu__finish_func(NULL, z);
   stu__pop_func_comp();

   o = stu__funceval(o, stua_globals); // initialize stu__globaldict
   if (stu__flow == FLOW_error)
      printf("Error: %s\n", ((stu__wrapper *) stu__ptr(stu__flow_val))->ptr);
   return 1;
error:
   stu__pop_func_comp();
   return 0;
}

stua_obj stu__myprint(stua_dict *context)
{
   stua_obj x = stu__get(context, stua_string("x"), stua_nil);
   if ((x & 1) == stu__float_tag) printf("%f", stu__getfloat(x));
   else if (stu__tag(x) == stu__int_tag) printf("%d", stu__int(x));
   else {
       stu__wrapper *s = stu__pw(x);
       if (s->type == STU___string || s->type == STU___error)
          printf("%s", s->ptr);
       else if (s->type == STU___dict) printf("{{dictionary}}");
       else if (s->type == STU___function) printf("[[function]]");
       else
          printf("[[ERROR:%s]]", s->ptr);
   }
   return x;
}

void stua_init(void)
{
   if (!stu__globaldict) {
      int i;
      stua_obj s;
      stu__func *f;

      stu__prec[ST_and] = stu__prec[ST_or] =                     1;
      stu__prec[ST_eq ] = stu__prec[ST_ne] = stu__prec[ST_le] =
       stu__prec[ST_ge] = stu__prec['>' ]  = stu__prec['<'] =    2;
      stu__prec[':']    =                                        3;
      stu__prec['&']    = stu__prec['|']   = stu__prec['^'] =    4;
      stu__prec['+']    = stu__prec['-']   =                     5;
      stu__prec['*']    = stu__prec['/']   = stu__prec['%'] =
       stu__prec[ST_shl]= stu__prec[ST_shr]= stu__prec[ST_shru]= 6;

      stu__end[')']   = stu__end[ST_end] = stu__end[ST_else] = 1;
      stu__end[ST_do] = stu__end[ST_elseif] = 1;

      stu__float_init();
      stu__lex_matcher = stb_lex_matcher();
      for (i=0; i < sizeof(stu__lexemes)/sizeof(stu__lexemes[0]); ++i)
         stb_lex_item(stu__lex_matcher, stu__lexemes[i].regex, stu__lexemes[i].stu__tok);

      stu__globaldict = stb_idict_new_size(64);
      stua_globals    = stu__makeobj(STU___dict, stu__globaldict, 0,0);
      stu__strings    = stb_sdict_new(0);

      stu__curbuf = stu__bufstart = "func _print(x) end\n"
      "func print()\n  var x=0 while _frame[x] != nil as x=x+1 do _print(_frame[x]) end end\n";
      stu__nexttoken();
      if (!stu__compile_global_scope())
         printf("Compile error in line %d: %s\n", stu__comp_err_line, stu__comp_err_str);

      s = stu__get(stu__globaldict, stua_string("_print"), stua_nil);
      if (stu__tag(s) == stu__ptr_tag && stu__ptr(s)->type == STU___function) {
         f = stu__pf(s);
         free(f->f.store);
         f->closure_source = 4;
         f->f.func = stu__myprint;
         f->code = NULL;
      }
   }
}

void stua_uninit(void)
{
   if (stu__globaldict) {
      stb_idict_remove_all(stu__globaldict);
      stb_arr_setlen(stu__gc_root_stack, 0);
      stua_gc(1);
      stb_idict_destroy(stu__globaldict);
      stb_sdict_delete(stu__strings);
      stb_matcher_free(stu__lex_matcher);
      stu__gc_ptrlist = stb_arr_free(stu__gc_ptrlist);
      func_stack = stb_arr_free(func_stack);
      stu__gc_root_stack = stb_arr_free(stu__gc_root_stack);
      stu__globaldict = NULL;
   }
}

void stua_run_script(char *s)
{
   stua_init();

   stu__curbuf = stu__bufstart = s;
   stu__nexttoken();

   stu__flow = FLOW_normal;

   if (!stu__compile_global_scope())
      printf("Compile error in line %d: %s\n", stu__comp_err_line, stu__comp_err_str);
   stua_gc(1);
}
#endif // STB_DEFINE

#endif // STB_STUA


#undef STB_EXTERN
#endif // STB_INCLUDE_STB_H