lib/littlefs: Add littlefs v1.7.2 source.

5 years ago · 669d1d20ab
4 changed files with 3301 additions and 0 deletions
--- a/lib/littlefs/lfs1.c
+++ b/lib/littlefs/lfs1.c
--- a/lib/littlefs/lfs1.h
+++ b/lib/littlefs/lfs1.h
@ -0,0 +1,501 @@
+/*
+ * The little filesystem
+ *
+ * Copyright (c) 2017, Arm Limited. All rights reserved.
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+#ifndef LFS1_H
+#define LFS1_H
+
+#include <stdint.h>
+#include <stdbool.h>
+
+#ifdef __cplusplus
+extern "C"
+{
+#endif
+
+
+/// Version info ///
+
+// Software library version
+// Major (top-nibble), incremented on backwards incompatible changes
+// Minor (bottom-nibble), incremented on feature additions
+#define LFS1_VERSION 0x00010007
+#define LFS1_VERSION_MAJOR (0xffff & (LFS1_VERSION >> 16))
+#define LFS1_VERSION_MINOR (0xffff & (LFS1_VERSION >>  0))
+
+// Version of On-disk data structures
+// Major (top-nibble), incremented on backwards incompatible changes
+// Minor (bottom-nibble), incremented on feature additions
+#define LFS1_DISK_VERSION 0x00010001
+#define LFS1_DISK_VERSION_MAJOR (0xffff & (LFS1_DISK_VERSION >> 16))
+#define LFS1_DISK_VERSION_MINOR (0xffff & (LFS1_DISK_VERSION >>  0))
+
+
+/// Definitions ///
+
+// Type definitions
+typedef uint32_t lfs1_size_t;
+typedef uint32_t lfs1_off_t;
+
+typedef int32_t  lfs1_ssize_t;
+typedef int32_t  lfs1_soff_t;
+
+typedef uint32_t lfs1_block_t;
+
+// Max name size in bytes
+#ifndef LFS1_NAME_MAX
+#define LFS1_NAME_MAX 255
+#endif
+
+// Max file size in bytes
+#ifndef LFS1_FILE_MAX
+#define LFS1_FILE_MAX 2147483647
+#endif
+
+// Possible error codes, these are negative to allow
+// valid positive return values
+enum lfs1_error {
+    LFS1_ERR_OK       = 0,    // No error
+    LFS1_ERR_IO       = -5,   // Error during device operation
+    LFS1_ERR_CORRUPT  = -52,  // Corrupted
+    LFS1_ERR_NOENT    = -2,   // No directory entry
+    LFS1_ERR_EXIST    = -17,  // Entry already exists
+    LFS1_ERR_NOTDIR   = -20,  // Entry is not a dir
+    LFS1_ERR_ISDIR    = -21,  // Entry is a dir
+    LFS1_ERR_NOTEMPTY = -39,  // Dir is not empty
+    LFS1_ERR_BADF     = -9,   // Bad file number
+    LFS1_ERR_FBIG     = -27,  // File too large
+    LFS1_ERR_INVAL    = -22,  // Invalid parameter
+    LFS1_ERR_NOSPC    = -28,  // No space left on device
+    LFS1_ERR_NOMEM    = -12,  // No more memory available
+};
+
+// File types
+enum lfs1_type {
+    LFS1_TYPE_REG        = 0x11,
+    LFS1_TYPE_DIR        = 0x22,
+    LFS1_TYPE_SUPERBLOCK = 0x2e,
+};
+
+// File open flags
+enum lfs1_open_flags {
+    // open flags
+    LFS1_O_RDONLY = 1,        // Open a file as read only
+    LFS1_O_WRONLY = 2,        // Open a file as write only
+    LFS1_O_RDWR   = 3,        // Open a file as read and write
+    LFS1_O_CREAT  = 0x0100,   // Create a file if it does not exist
+    LFS1_O_EXCL   = 0x0200,   // Fail if a file already exists
+    LFS1_O_TRUNC  = 0x0400,   // Truncate the existing file to zero size
+    LFS1_O_APPEND = 0x0800,   // Move to end of file on every write
+
+    // internally used flags
+    LFS1_F_DIRTY   = 0x10000, // File does not match storage
+    LFS1_F_WRITING = 0x20000, // File has been written since last flush
+    LFS1_F_READING = 0x40000, // File has been read since last flush
+    LFS1_F_ERRED   = 0x80000, // An error occured during write
+};
+
+// File seek flags
+enum lfs1_whence_flags {
+    LFS1_SEEK_SET = 0,   // Seek relative to an absolute position
+    LFS1_SEEK_CUR = 1,   // Seek relative to the current file position
+    LFS1_SEEK_END = 2,   // Seek relative to the end of the file
+};
+
+
+// Configuration provided during initialization of the littlefs
+struct lfs1_config {
+    // Opaque user provided context that can be used to pass
+    // information to the block device operations
+    void *context;
+
+    // Read a region in a block. Negative error codes are propogated
+    // to the user.
+    int (*read)(const struct lfs1_config *c, lfs1_block_t block,
+            lfs1_off_t off, void *buffer, lfs1_size_t size);
+
+    // Program a region in a block. The block must have previously
+    // been erased. Negative error codes are propogated to the user.
+    // May return LFS1_ERR_CORRUPT if the block should be considered bad.
+    int (*prog)(const struct lfs1_config *c, lfs1_block_t block,
+            lfs1_off_t off, const void *buffer, lfs1_size_t size);
+
+    // Erase a block. A block must be erased before being programmed.
+    // The state of an erased block is undefined. Negative error codes
+    // are propogated to the user.
+    // May return LFS1_ERR_CORRUPT if the block should be considered bad.
+    int (*erase)(const struct lfs1_config *c, lfs1_block_t block);
+
+    // Sync the state of the underlying block device. Negative error codes
+    // are propogated to the user.
+    int (*sync)(const struct lfs1_config *c);
+
+    // Minimum size of a block read. This determines the size of read buffers.
+    // This may be larger than the physical read size to improve performance
+    // by caching more of the block device.
+    lfs1_size_t read_size;
+
+    // Minimum size of a block program. This determines the size of program
+    // buffers. This may be larger than the physical program size to improve
+    // performance by caching more of the block device.
+    // Must be a multiple of the read size.
+    lfs1_size_t prog_size;
+
+    // Size of an erasable block. This does not impact ram consumption and
+    // may be larger than the physical erase size. However, this should be
+    // kept small as each file currently takes up an entire block.
+    // Must be a multiple of the program size.
+    lfs1_size_t block_size;
+
+    // Number of erasable blocks on the device.
+    lfs1_size_t block_count;
+
+    // Number of blocks to lookahead during block allocation. A larger
+    // lookahead reduces the number of passes required to allocate a block.
+    // The lookahead buffer requires only 1 bit per block so it can be quite
+    // large with little ram impact. Should be a multiple of 32.
+    lfs1_size_t lookahead;
+
+    // Optional, statically allocated read buffer. Must be read sized.
+    void *read_buffer;
+
+    // Optional, statically allocated program buffer. Must be program sized.
+    void *prog_buffer;
+
+    // Optional, statically allocated lookahead buffer. Must be 1 bit per
+    // lookahead block.
+    void *lookahead_buffer;
+
+    // Optional, statically allocated buffer for files. Must be program sized.
+    // If enabled, only one file may be opened at a time.
+    void *file_buffer;
+};
+
+// Optional configuration provided during lfs1_file_opencfg
+struct lfs1_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 lfs1_info {
+    // Type of the file, either LFS1_TYPE_REG or LFS1_TYPE_DIR
+    uint8_t type;
+
+    // Size of the file, only valid for REG files
+    lfs1_size_t size;
+
+    // Name of the file stored as a null-terminated string
+    char name[LFS1_NAME_MAX+1];
+};
+
+
+/// littlefs data structures ///
+typedef struct lfs1_entry {
+    lfs1_off_t off;
+
+    struct lfs1_disk_entry {
+        uint8_t type;
+        uint8_t elen;
+        uint8_t alen;
+        uint8_t nlen;
+        union {
+            struct {
+                lfs1_block_t head;
+                lfs1_size_t size;
+            } file;
+            lfs1_block_t dir[2];
+        } u;
+    } d;
+} lfs1_entry_t;
+
+typedef struct lfs1_cache {
+    lfs1_block_t block;
+    lfs1_off_t off;
+    uint8_t *buffer;
+} lfs1_cache_t;
+
+typedef struct lfs1_file {
+    struct lfs1_file *next;
+    lfs1_block_t pair[2];
+    lfs1_off_t poff;
+
+    lfs1_block_t head;
+    lfs1_size_t size;
+
+    const struct lfs1_file_config *cfg;
+    uint32_t flags;
+    lfs1_off_t pos;
+    lfs1_block_t block;
+    lfs1_off_t off;
+    lfs1_cache_t cache;
+} lfs1_file_t;
+
+typedef struct lfs1_dir {
+    struct lfs1_dir *next;
+    lfs1_block_t pair[2];
+    lfs1_off_t off;
+
+    lfs1_block_t head[2];
+    lfs1_off_t pos;
+
+    struct lfs1_disk_dir {
+        uint32_t rev;
+        lfs1_size_t size;
+        lfs1_block_t tail[2];
+    } d;
+} lfs1_dir_t;
+
+typedef struct lfs1_superblock {
+    lfs1_off_t off;
+
+    struct lfs1_disk_superblock {
+        uint8_t type;
+        uint8_t elen;
+        uint8_t alen;
+        uint8_t nlen;
+        lfs1_block_t root[2];
+        uint32_t block_size;
+        uint32_t block_count;
+        uint32_t version;
+        char magic[8];
+    } d;
+} lfs1_superblock_t;
+
+typedef struct lfs1_free {
+    lfs1_block_t off;
+    lfs1_block_t size;
+    lfs1_block_t i;
+    lfs1_block_t ack;
+    uint32_t *buffer;
+} lfs1_free_t;
+
+// The littlefs type
+typedef struct lfs1 {
+    const struct lfs1_config *cfg;
+
+    lfs1_block_t root[2];
+    lfs1_file_t *files;
+    lfs1_dir_t *dirs;
+
+    lfs1_cache_t rcache;
+    lfs1_cache_t pcache;
+
+    lfs1_free_t free;
+    bool deorphaned;
+    bool moving;
+} lfs1_t;
+
+
+/// Filesystem functions ///
+
+// 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. The config struct must
+// be zeroed for defaults and backwards compatibility.
+//
+// Returns a negative error code on failure.
+int lfs1_format(lfs1_t *lfs1, const struct lfs1_config *config);
+
+// Mounts a littlefs
+//
+// Requires a littlefs object and config struct. Multiple filesystems
+// may be mounted simultaneously with multiple littlefs objects. Both
+// lfs1 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 lfs1_mount(lfs1_t *lfs1, const struct lfs1_config *config);
+
+// Unmounts a littlefs
+//
+// Does nothing besides releasing any allocated resources.
+// Returns a negative error code on failure.
+int lfs1_unmount(lfs1_t *lfs1);
+
+/// General operations ///
+
+// Removes a file or directory
+//
+// If removing a directory, the directory must be empty.
+// Returns a negative error code on failure.
+int lfs1_remove(lfs1_t *lfs1, const char *path);
+
+// Rename or move a file or directory
+//
+// If the destination exists, it must match the source in type.
+// If the destination is a directory, the directory must be empty.
+//
+// Returns a negative error code on failure.
+int lfs1_rename(lfs1_t *lfs1, const char *oldpath, const char *newpath);
+
+// Find info about a file or directory
+//
+// Fills out the info structure, based on the specified file or directory.
+// Returns a negative error code on failure.
+int lfs1_stat(lfs1_t *lfs1, const char *path, struct lfs1_info *info);
+
+
+/// File operations ///
+
+// Open a file
+//
+// The mode that the file is opened in is determined by the flags, which
+// are values from the enum lfs1_open_flags that are bitwise-ored together.
+//
+// Returns a negative error code on failure.
+int lfs1_file_open(lfs1_t *lfs1, lfs1_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 lfs1_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 lfs1_file_opencfg(lfs1_t *lfs1, lfs1_file_t *file,
+        const char *path, int flags,
+        const struct lfs1_file_config *config);
+
+// Close a file
+//
+// Any pending writes are written out to storage as though
+// sync had been called and releases any allocated resources.
+//
+// Returns a negative error code on failure.
+int lfs1_file_close(lfs1_t *lfs1, lfs1_file_t *file);
+
+// Synchronize a file on storage
+//
+// Any pending writes are written out to storage.
+// Returns a negative error code on failure.
+int lfs1_file_sync(lfs1_t *lfs1, lfs1_file_t *file);
+
+// Read data from file
+//
+// Takes a buffer and size indicating where to store the read data.
+// Returns the number of bytes read, or a negative error code on failure.
+lfs1_ssize_t lfs1_file_read(lfs1_t *lfs1, lfs1_file_t *file,
+        void *buffer, lfs1_size_t size);
+
+// Write data to file
+//
+// Takes a buffer and size indicating the data to write. The file will not
+// actually be updated on the storage until either sync or close is called.
+//
+// Returns the number of bytes written, or a negative error code on failure.
+lfs1_ssize_t lfs1_file_write(lfs1_t *lfs1, lfs1_file_t *file,
+        const void *buffer, lfs1_size_t size);
+
+// Change the position of the file
+//
+// The change in position is determined by the offset and whence flag.
+// Returns the old position of the file, or a negative error code on failure.
+lfs1_soff_t lfs1_file_seek(lfs1_t *lfs1, lfs1_file_t *file,
+        lfs1_soff_t off, int whence);
+
+// Truncates the size of the file to the specified size
+//
+// Returns a negative error code on failure.
+int lfs1_file_truncate(lfs1_t *lfs1, lfs1_file_t *file, lfs1_off_t size);
+
+// Return the position of the file
+//
+// Equivalent to lfs1_file_seek(lfs1, file, 0, LFS1_SEEK_CUR)
+// Returns the position of the file, or a negative error code on failure.
+lfs1_soff_t lfs1_file_tell(lfs1_t *lfs1, lfs1_file_t *file);
+
+// Change the position of the file to the beginning of the file
+//
+// Equivalent to lfs1_file_seek(lfs1, file, 0, LFS1_SEEK_CUR)
+// Returns a negative error code on failure.
+int lfs1_file_rewind(lfs1_t *lfs1, lfs1_file_t *file);
+
+// Return the size of the file
+//
+// Similar to lfs1_file_seek(lfs1, file, 0, LFS1_SEEK_END)
+// Returns the size of the file, or a negative error code on failure.
+lfs1_soff_t lfs1_file_size(lfs1_t *lfs1, lfs1_file_t *file);
+
+
+/// Directory operations ///
+
+// Create a directory
+//
+// Returns a negative error code on failure.
+int lfs1_mkdir(lfs1_t *lfs1, const char *path);
+
+// Open a directory
+//
+// Once open a directory can be used with read to iterate over files.
+// Returns a negative error code on failure.
+int lfs1_dir_open(lfs1_t *lfs1, lfs1_dir_t *dir, const char *path);
+
+// Close a directory
+//
+// Releases any allocated resources.
+// Returns a negative error code on failure.
+int lfs1_dir_close(lfs1_t *lfs1, lfs1_dir_t *dir);
+
+// Read an entry in the directory
+//
+// Fills out the info structure, based on the specified file or directory.
+// Returns a negative error code on failure.
+int lfs1_dir_read(lfs1_t *lfs1, lfs1_dir_t *dir, struct lfs1_info *info);
+
+// Change the position of the directory
+//
+// The new off must be a value previous returned from tell and specifies
+// an absolute offset in the directory seek.
+//
+// Returns a negative error code on failure.
+int lfs1_dir_seek(lfs1_t *lfs1, lfs1_dir_t *dir, lfs1_off_t off);
+
+// Return the position of the directory
+//
+// The returned offset is only meant to be consumed by seek and may not make
+// sense, but does indicate the current position in the directory iteration.
+//
+// Returns the position of the directory, or a negative error code on failure.
+lfs1_soff_t lfs1_dir_tell(lfs1_t *lfs1, lfs1_dir_t *dir);
+
+// Change the position of the directory to the beginning of the directory
+//
+// Returns a negative error code on failure.
+int lfs1_dir_rewind(lfs1_t *lfs1, lfs1_dir_t *dir);
+
+
+/// Miscellaneous littlefs specific operations ///
+
+// Traverse through all blocks in use by the filesystem
+//
+// The provided callback will be called with each block address that is
+// currently in use by the filesystem. This can be used to determine which
+// blocks are in use or how much of the storage is available.
+//
+// Returns a negative error code on failure.
+int lfs1_traverse(lfs1_t *lfs1, int (*cb)(void*, lfs1_block_t), void *data);
+
+// Prunes any recoverable errors that may have occured in the filesystem
+//
+// Not needed to be called by user unless an operation is interrupted
+// but the filesystem is still mounted. This is already called on first
+// allocation.
+//
+// Returns a negative error code on failure.
+int lfs1_deorphan(lfs1_t *lfs1);
+
+
+#ifdef __cplusplus
+} /* extern "C" */
+#endif
+
+#endif
--- a/lib/littlefs/lfs1_util.c
+++ b/lib/littlefs/lfs1_util.c
@ -0,0 +1,31 @@
+/*
+ * lfs1 util functions
+ *
+ * Copyright (c) 2017, Arm Limited. All rights reserved.
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+#include "lfs1_util.h"
+
+// Only compile if user does not provide custom config
+#ifndef LFS1_CONFIG
+
+
+// Software CRC implementation with small lookup table
+void lfs1_crc(uint32_t *restrict crc, const void *buffer, size_t size) {
+    static const uint32_t rtable[16] = {
+        0x00000000, 0x1db71064, 0x3b6e20c8, 0x26d930ac,
+        0x76dc4190, 0x6b6b51f4, 0x4db26158, 0x5005713c,
+        0xedb88320, 0xf00f9344, 0xd6d6a3e8, 0xcb61b38c,
+        0x9b64c2b0, 0x86d3d2d4, 0xa00ae278, 0xbdbdf21c,
+    };
+
+    const uint8_t *data = buffer;
+
+    for (size_t i = 0; i < size; i++) {
+        *crc = (*crc >> 4) ^ rtable[(*crc ^ (data[i] >> 0)) & 0xf];
+        *crc = (*crc >> 4) ^ rtable[(*crc ^ (data[i] >> 4)) & 0xf];
+    }
+}
+
+
+#endif
--- a/lib/littlefs/lfs1_util.h
+++ b/lib/littlefs/lfs1_util.h
@ -0,0 +1,186 @@
+/*
+ * lfs1 utility functions
+ *
+ * Copyright (c) 2017, Arm Limited. All rights reserved.
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+#ifndef LFS1_UTIL_H
+#define LFS1_UTIL_H
+
+// Users can override lfs1_util.h with their own configuration by defining
+// LFS1_CONFIG as a header file to include (-DLFS1_CONFIG=lfs1_config.h).
+//
+// If LFS1_CONFIG is used, none of the default utils will be emitted and must be
+// provided by the config file. To start I would suggest copying lfs1_util.h and
+// modifying as needed.
+#ifdef LFS1_CONFIG
+#define LFS1_STRINGIZE(x) LFS1_STRINGIZE2(x)
+#define LFS1_STRINGIZE2(x) #x
+#include LFS1_STRINGIZE(LFS1_CONFIG)
+#else
+
+// System includes
+#include <stdint.h>
+#include <stdbool.h>
+#include <string.h>
+
+#ifndef LFS1_NO_MALLOC
+#include <stdlib.h>
+#endif
+#ifndef LFS1_NO_ASSERT
+#include <assert.h>
+#endif
+#if !defined(LFS1_NO_DEBUG) || !defined(LFS1_NO_WARN) || !defined(LFS1_NO_ERROR)
+#include <stdio.h>
+#endif
+
+#ifdef __cplusplus
+extern "C"
+{
+#endif
+
+
+// Macros, may be replaced by system specific wrappers. Arguments to these
+// macros must not have side-effects as the macros can be removed for a smaller
+// code footprint
+
+// Logging functions
+#ifndef LFS1_NO_DEBUG
+#define LFS1_DEBUG(fmt, ...) \
+    printf("lfs1 debug:%d: " fmt "\n", __LINE__, __VA_ARGS__)
+#else
+#define LFS1_DEBUG(fmt, ...)
+#endif
+
+#ifndef LFS1_NO_WARN
+#define LFS1_WARN(fmt, ...) \
+    printf("lfs1 warn:%d: " fmt "\n", __LINE__, __VA_ARGS__)
+#else
+#define LFS1_WARN(fmt, ...)
+#endif
+
+#ifndef LFS1_NO_ERROR
+#define LFS1_ERROR(fmt, ...) \
+    printf("lfs1 error:%d: " fmt "\n", __LINE__, __VA_ARGS__)
+#else
+#define LFS1_ERROR(fmt, ...)
+#endif
+
+// Runtime assertions
+#ifndef LFS1_NO_ASSERT
+#define LFS1_ASSERT(test) assert(test)
+#else
+#define LFS1_ASSERT(test)
+#endif
+
+
+// Builtin functions, these may be replaced by more efficient
+// toolchain-specific implementations. LFS1_NO_INTRINSICS falls back to a more
+// expensive basic C implementation for debugging purposes
+
+// Min/max functions for unsigned 32-bit numbers
+static inline uint32_t lfs1_max(uint32_t a, uint32_t b) {
+    return (a > b) ? a : b;
+}
+
+static inline uint32_t lfs1_min(uint32_t a, uint32_t b) {
+    return (a < b) ? a : b;
+}
+
+// Find the next smallest power of 2 less than or equal to a
+static inline uint32_t lfs1_npw2(uint32_t a) {
+#if !defined(LFS1_NO_INTRINSICS) && (defined(__GNUC__) || defined(__CC_ARM))
+    return 32 - __builtin_clz(a-1);
+#else
+    uint32_t r = 0;
+    uint32_t s;
+    a -= 1;
+    s = (a > 0xffff) << 4; a >>= s; r |= s;
+    s = (a > 0xff  ) << 3; a >>= s; r |= s;
+    s = (a > 0xf   ) << 2; a >>= s; r |= s;
+    s = (a > 0x3   ) << 1; a >>= s; r |= s;
+    return (r | (a >> 1)) + 1;
+#endif
+}
+
+// Count the number of trailing binary zeros in a
+// lfs1_ctz(0) may be undefined
+static inline uint32_t lfs1_ctz(uint32_t a) {
+#if !defined(LFS1_NO_INTRINSICS) && defined(__GNUC__)
+    return __builtin_ctz(a);
+#else
+    return lfs1_npw2((a & -a) + 1) - 1;
+#endif
+}
+
+// Count the number of binary ones in a
+static inline uint32_t lfs1_popc(uint32_t a) {
+#if !defined(LFS1_NO_INTRINSICS) && (defined(__GNUC__) || defined(__CC_ARM))
+    return __builtin_popcount(a);
+#else
+    a = a - ((a >> 1) & 0x55555555);
+    a = (a & 0x33333333) + ((a >> 2) & 0x33333333);
+    return (((a + (a >> 4)) & 0xf0f0f0f) * 0x1010101) >> 24;
+#endif
+}
+
+// Find the sequence comparison of a and b, this is the distance
+// between a and b ignoring overflow
+static inline int lfs1_scmp(uint32_t a, uint32_t b) {
+    return (int)(unsigned)(a - b);
+}
+
+// Convert from 32-bit little-endian to native order
+static inline uint32_t lfs1_fromle32(uint32_t a) {
+#if !defined(LFS1_NO_INTRINSICS) && ( \
+    (defined(  BYTE_ORDER  ) &&   BYTE_ORDER   ==   ORDER_LITTLE_ENDIAN  ) || \
+    (defined(__BYTE_ORDER  ) && __BYTE_ORDER   == __ORDER_LITTLE_ENDIAN  ) || \
+    (defined(__BYTE_ORDER__) && __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__))
+    return a;
+#elif !defined(LFS1_NO_INTRINSICS) && ( \
+    (defined(  BYTE_ORDER  ) &&   BYTE_ORDER   ==   ORDER_BIG_ENDIAN  ) || \
+    (defined(__BYTE_ORDER  ) && __BYTE_ORDER   == __ORDER_BIG_ENDIAN  ) || \
+    (defined(__BYTE_ORDER__) && __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__))
+    return __builtin_bswap32(a);
+#else
+    return (((uint8_t*)&a)[0] <<  0) |
+           (((uint8_t*)&a)[1] <<  8) |
+           (((uint8_t*)&a)[2] << 16) |
+           (((uint8_t*)&a)[3] << 24);
+#endif
+}
+
+// Convert to 32-bit little-endian from native order
+static inline uint32_t lfs1_tole32(uint32_t a) {
+    return lfs1_fromle32(a);
+}
+
+// Calculate CRC-32 with polynomial = 0x04c11db7
+void lfs1_crc(uint32_t *crc, const void *buffer, size_t size);
+
+// Allocate memory, only used if buffers are not provided to littlefs
+static inline void *lfs1_malloc(size_t size) {
+#ifndef LFS1_NO_MALLOC
+    return malloc(size);
+#else
+    (void)size;
+    return NULL;
+#endif
+}
+
+// Deallocate memory, only used if buffers are not provided to littlefs
+static inline void lfs1_free(void *p) {
+#ifndef LFS1_NO_MALLOC
+    free(p);
+#else
+    (void)p;
+#endif
+}
+
+
+#ifdef __cplusplus
+} /* extern "C" */
+#endif
+
+#endif
+#endif