From 501d564eb0fa96eb66b4ad239a2a56e4fa59c95f Mon Sep 17 00:00:00 2001
From: Frantisek Boranek <frantisek.boranek@firma.seznam.cz>
Date: Thu, 18 Oct 2018 17:19:42 +0200
Subject: [PATCH] use std::hash and C++11

---
 configure.ac          |  3 ++-
 src/Makefile.am       |  2 +-
 src/tengfilesystem.cc | 20 +++++++++++++-------
 3 files changed, 16 insertions(+), 9 deletions(-)

diff --git a/configure.ac b/configure.ac
index d84b558..d56a03a 100644
--- a/configure.ac
+++ b/configure.ac
@@ -53,6 +53,8 @@ AC_CONFIG_FILES([tests/Makefile])
 
 # check for C++ compiler
 AC_PROG_CXX
+AC_LANG_CPLUSPLUS
+AX_CHECK_COMPILE_FLAG([-std=c++11], [],[AC_MSG_ERROR([Compiler without c++11])])
 
 # pkg config
 PKG_PROG_PKG_CONFIG([0.25])
@@ -145,7 +147,6 @@ AC_CHECK_HEADERS(fenv.h)
 AC_CHECK_LIB(m, floor)
 AC_REPLACE_FUNCS([trunc round])
 
-AC_LANG_CPLUSPLUS
 AC_CHECK_LIB([pcre++], [_init],,AC_MSG_ERROR([pcre++ not installed]))
 
 AX_CHECK_COMPILE_FLAG([-std=c++14], [
diff --git a/src/Makefile.am b/src/Makefile.am
index dc2d7c5..d47b41d 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -39,7 +39,7 @@
 AM_CXXFLAGS = -Wall
 
 # extra compiler options
-AM_CPPFLAGS = -D_ISOC99_SOURCE -fPIC ${DEPENS_CFLAGS}
+AM_CPPFLAGS = -std=c++11 -D_ISOC99_SOURCE -fPIC ${DEPENS_CFLAGS}
 
 # these are generated and thus ought to be prepared before anything else
 BUILT_SOURCES = tenglex2.cc tengsyntax.cc
diff --git a/src/tengfilesystem.cc b/src/tengfilesystem.cc
index 3ea9444..1fc2700 100644
--- a/src/tengfilesystem.cc
+++ b/src/tengfilesystem.cc
@@ -20,14 +20,13 @@
 #include <sys/stat.h>
 #include <unistd.h>
 
+#include <functional>
 #include <stdexcept>
 #include <stdio.h>
 
 #include "tengfilesystem.h"
-#include "tengutil.h"
 #include "tengplatform.h"
-
-#include <boost/functional/hash.hpp>
+#include "tengutil.h"
 
 namespace Teng {
     
@@ -42,6 +41,13 @@ static std::string makeFilename(const std::string& root, const std::string& file
     return filename;
 }
 
+template<class S>
+static void hashCombine(std::size_t& seed, S const& value)
+{
+    std::size_t hash = std::hash<S>{}(value);
+    seed ^= hash + 0x9e3779b9 + (seed<<6) + (seed>>2); // or use boost::hash_combine
+}
+
 Filesystem_t::Filesystem_t(const std::string& root_)
     : root(root_)
 {
@@ -96,10 +102,10 @@ size_t Filesystem_t::hash(const std::string& filename_) const
         throw std::runtime_error("File '" + filename + "' is a directory");
     }
 
-    boost::hash_combine(seed, buf.st_ino);
-    boost::hash_combine(seed, buf.st_size);
-    boost::hash_combine(seed, buf.st_mtime);
-    boost::hash_combine(seed, buf.st_ctime);
+    hashCombine(seed, buf.st_ino);   // unsigned long int - inode number
+    hashCombine(seed, buf.st_size);  // long - total size, in bytes
+    hashCombine(seed, buf.st_mtime); // long - time of last modification
+    hashCombine(seed, buf.st_ctime); // long - time of last status change
 
     return seed;
 }