Added file config structure and lfs_file_opencfg

The optional config structure options up the possibility of adding
file-level configuration in a backwards compatible manner.

Also adds possibility to open multiple files with LFS_NO_MALLOC
enabled thanks to dpgeorge

Also bumped minor version to v1.5

lfs.c

@@ -1282,8 +1282,9 @@ static int lfs_ctz_traverse(lfs_t *lfs,
 
 
 /// Top level file operations ///
-int lfs_file_open(lfs_t *lfs, lfs_file_t *file,
- const char *path, int flags) {
+int lfs_file_opencfg(lfs_t *lfs, lfs_file_t *file,
+ const char *path, int flags,
+ const struct lfs_file_config *cfg) {
  // deorphan if we haven't yet, needed at most once after poweron
  if ((flags & 3) != LFS_O_RDONLY && !lfs->deorphaned) {
  int err = lfs_deorphan(lfs);
@@ -1323,6 +1324,7 @@ int lfs_file_open(lfs_t *lfs, lfs_file_t *file,
  }
 
  // setup file struct
+ file->cfg = cfg;
  file->pair[0] = cwd.pair[0];
  file->pair[1] = cwd.pair[1];
  file->poff = entry.off;
@@ -1340,7 +1342,10 @@ int lfs_file_open(lfs_t *lfs, lfs_file_t *file,
  }
 
  // allocate buffer if needed
- if (lfs->cfg->file_buffer) {
+ file->cache.block = 0xffffffff;
+ if (file->cfg && file->cfg->buffer) {
+ file->cache.buffer = file->cfg->buffer;
+ } else if (lfs->cfg->file_buffer) {
  if (lfs->files) {
  // already in use
  return LFS_ERR_NOMEM;
@@ -1368,6 +1373,11 @@ int lfs_file_open(lfs_t *lfs, lfs_file_t *file,
  return 0;
 }
 
+int lfs_file_open(lfs_t *lfs, lfs_file_t *file,
+ const char *path, int flags) {
+ return lfs_file_opencfg(lfs, file, path, flags, NULL);
+}
+
 int lfs_file_close(lfs_t *lfs, lfs_file_t *file) {
  int err = lfs_file_sync(lfs, file);
 
@@ -1380,7 +1390,7 @@ int lfs_file_close(lfs_t *lfs, lfs_file_t *file) {
  }
 
  // clean up memory
- if (!lfs->cfg->file_buffer) {
+ if (!(file->cfg && file->cfg->buffer) && !lfs->cfg->file_buffer) {
  lfs_free(file->cache.buffer);
  }
 

lfs.h

@@ -21,7 +21,7 @@ extern "C"
 // Software library version
 // Major (top-nibble), incremented on backwards incompatible changes
 // Minor (bottom-nibble), incremented on feature additions
-#define LFS_VERSION 0x00010004
+#define LFS_VERSION 0x00010005
 #define LFS_VERSION_MAJOR (0xffff & (LFS_VERSION >> 16))
 #define LFS_VERSION_MINOR (0xffff & (LFS_VERSION >> 0))
 
@@ -167,6 +167,12 @@ struct lfs_config {
  void *file_buffer;
 };
 
+// Optional configuration provided during lfs_file_opencfg
+struct lfs_file_config {
+ // Optional, statically allocated buffer for files. Must be program sized.
+ // If NULL, malloc will be used by default.
+ void *buffer;
+};
 
 // File info structure
 struct lfs_info {
@@ -214,6 +220,7 @@ typedef struct lfs_file {
  lfs_block_t head;
  lfs_size_t size;
 
+ const struct lfs_file_config *cfg;
  uint32_t flags;
  lfs_off_t pos;
  lfs_block_t block;
@@ -281,7 +288,8 @@ typedef struct lfs {
 // Format a block device with the littlefs
 //
 // Requires a littlefs object and config struct. This clobbers the littlefs
-// object, and does not leave the filesystem mounted.
+// object, and does not leave the filesystem mounted. The config struct must
+// be zeroed for defaults and backwards compatibility.
 //
 // Returns a negative error code on failure.
 int lfs_format(lfs_t *lfs, const struct lfs_config *config);
@@ -290,7 +298,8 @@ int lfs_format(lfs_t *lfs, const struct lfs_config *config);
 //
 // Requires a littlefs object and config struct. Multiple filesystems
 // may be mounted simultaneously with multiple littlefs objects. Both
-// lfs and config must be allocated while mounted.
+// lfs and config must be allocated while mounted. The config struct must
+// be zeroed for defaults and backwards compatibility.
 //
 // Returns a negative error code on failure.
 int lfs_mount(lfs_t *lfs, const struct lfs_config *config);
@@ -328,14 +337,27 @@ int lfs_stat(lfs_t *lfs, const char *path, struct lfs_info *info);
 
 // Open a file
 //
-// The mode that the file is opened in is determined
-// by the flags, which are values from the enum lfs_open_flags
-// that are bitwise-ored together.
+// The mode that the file is opened in is determined by the flags, which
+// are values from the enum lfs_open_flags that are bitwise-ored together.
 //
 // Returns a negative error code on failure.
 int lfs_file_open(lfs_t *lfs, lfs_file_t *file,
  const char *path, int flags);
 
+// Open a file with extra configuration
+//
+// The mode that the file is opened in is determined by the flags, which
+// are values from the enum lfs_open_flags that are bitwise-ored together.
+//
+// The config struct provides additional config options per file as described
+// above. The config struct must be allocated while the file is open, and the
+// config struct must be zeroed for defaults and backwards compatibility.
+//
+// Returns a negative error code on failure.
+int lfs_file_opencfg(lfs_t *lfs, lfs_file_t *file,
+ const char *path, int flags,
+ const struct lfs_file_config *config);
+
 // Close a file
 //
 // Any pending writes are written out to storage as though