mirror of
https://gitee.com/openharmony/third_party_littlefs
synced 2024-11-27 09:01:27 +00:00
20b669a23d
Found while testing big-endian support. Basically, if littlefs is really really unlucky, the block allocator could kick in while committing a file's CTZ reference. If this happens, the block allocator will need to traverse all CTZ skip-lists in memory, including the skip-list we're committing. This means we can't convert the CTZ's endianness in place, and need to make a copy on big-endian systems. We rely on dead-code elimination from the compiler to make the conditional behaviour for big-endian vs little-endian system a noop determined by the lfs_tole32 intrinsic.
218 lines
6.0 KiB
C
218 lines
6.0 KiB
C
/*
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* lfs utility functions
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*
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* Copyright (c) 2017, Arm Limited. All rights reserved.
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* SPDX-License-Identifier: BSD-3-Clause
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*/
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#ifndef LFS_UTIL_H
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#define LFS_UTIL_H
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// Users can override lfs_util.h with their own configuration by defining
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// LFS_CONFIG as a header file to include (-DLFS_CONFIG=lfs_config.h).
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//
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// If LFS_CONFIG is used, none of the default utils will be emitted and must be
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// provided by the config file. To start, I would suggest copying lfs_util.h
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// and modifying as needed.
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#ifdef LFS_CONFIG
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#define LFS_STRINGIZE(x) LFS_STRINGIZE2(x)
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#define LFS_STRINGIZE2(x) #x
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#include LFS_STRINGIZE(LFS_CONFIG)
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#else
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// System includes
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#include <stdint.h>
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#include <stdbool.h>
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#include <string.h>
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#include <inttypes.h>
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#ifndef LFS_NO_MALLOC
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#include <stdlib.h>
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#endif
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#ifndef LFS_NO_ASSERT
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#include <assert.h>
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#endif
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#if !defined(LFS_NO_DEBUG) || !defined(LFS_NO_WARN) || !defined(LFS_NO_ERROR)
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#include <stdio.h>
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#endif
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#ifdef __cplusplus
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extern "C"
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{
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#endif
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// Macros, may be replaced by system specific wrappers. Arguments to these
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// macros must not have side-effects as the macros can be removed for a smaller
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// code footprint
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// Logging functions
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#ifndef LFS_NO_DEBUG
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#define LFS_DEBUG(fmt, ...) \
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printf("lfs debug:%d: " fmt "\n", __LINE__, __VA_ARGS__)
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#else
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#define LFS_DEBUG(fmt, ...)
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#endif
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#ifndef LFS_NO_WARN
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#define LFS_WARN(fmt, ...) \
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printf("lfs warn:%d: " fmt "\n", __LINE__, __VA_ARGS__)
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#else
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#define LFS_WARN(fmt, ...)
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#endif
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#ifndef LFS_NO_ERROR
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#define LFS_ERROR(fmt, ...) \
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printf("lfs error:%d: " fmt "\n", __LINE__, __VA_ARGS__)
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#else
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#define LFS_ERROR(fmt, ...)
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#endif
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// Runtime assertions
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#ifndef LFS_NO_ASSERT
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#define LFS_ASSERT(test) assert(test)
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#else
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#define LFS_ASSERT(test)
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#endif
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// Builtin functions, these may be replaced by more efficient
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// toolchain-specific implementations. LFS_NO_INTRINSICS falls back to a more
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// expensive basic C implementation for debugging purposes
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// Min/max functions for unsigned 32-bit numbers
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static inline uint32_t lfs_max(uint32_t a, uint32_t b) {
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return (a > b) ? a : b;
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}
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static inline uint32_t lfs_min(uint32_t a, uint32_t b) {
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return (a < b) ? a : b;
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}
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// Align to nearest multiple of a size
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static inline uint32_t lfs_aligndown(uint32_t a, uint32_t alignment) {
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return a - (a % alignment);
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}
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static inline uint32_t lfs_alignup(uint32_t a, uint32_t alignment) {
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return lfs_aligndown(a + alignment-1, alignment);
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}
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// Find the next smallest power of 2 less than or equal to a
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static inline uint32_t lfs_npw2(uint32_t a) {
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#if !defined(LFS_NO_INTRINSICS) && (defined(__GNUC__) || defined(__CC_ARM))
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return 32 - __builtin_clz(a-1);
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#else
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uint32_t r = 0;
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uint32_t s;
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a -= 1;
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s = (a > 0xffff) << 4; a >>= s; r |= s;
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s = (a > 0xff ) << 3; a >>= s; r |= s;
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s = (a > 0xf ) << 2; a >>= s; r |= s;
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s = (a > 0x3 ) << 1; a >>= s; r |= s;
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return (r | (a >> 1)) + 1;
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#endif
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}
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// Count the number of trailing binary zeros in a
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// lfs_ctz(0) may be undefined
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static inline uint32_t lfs_ctz(uint32_t a) {
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#if !defined(LFS_NO_INTRINSICS) && defined(__GNUC__)
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return __builtin_ctz(a);
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#else
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return lfs_npw2((a & -a) + 1) - 1;
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#endif
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}
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// Count the number of binary ones in a
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static inline uint32_t lfs_popc(uint32_t a) {
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#if !defined(LFS_NO_INTRINSICS) && (defined(__GNUC__) || defined(__CC_ARM))
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return __builtin_popcount(a);
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#else
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a = a - ((a >> 1) & 0x55555555);
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a = (a & 0x33333333) + ((a >> 2) & 0x33333333);
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return (((a + (a >> 4)) & 0xf0f0f0f) * 0x1010101) >> 24;
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#endif
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}
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// Find the sequence comparison of a and b, this is the distance
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// between a and b ignoring overflow
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static inline int lfs_scmp(uint32_t a, uint32_t b) {
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return (int)(unsigned)(a - b);
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}
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// Convert between 32-bit little-endian and native order
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static inline uint32_t lfs_fromle32(uint32_t a) {
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#if !defined(LFS_NO_INTRINSICS) && ( \
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(defined( BYTE_ORDER ) && BYTE_ORDER == ORDER_LITTLE_ENDIAN ) || \
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(defined(__BYTE_ORDER ) && __BYTE_ORDER == __ORDER_LITTLE_ENDIAN ) || \
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(defined(__BYTE_ORDER__) && __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__))
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return a;
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#elif !defined(LFS_NO_INTRINSICS) && ( \
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(defined( BYTE_ORDER ) && BYTE_ORDER == ORDER_BIG_ENDIAN ) || \
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(defined(__BYTE_ORDER ) && __BYTE_ORDER == __ORDER_BIG_ENDIAN ) || \
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(defined(__BYTE_ORDER__) && __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__))
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return __builtin_bswap32(a);
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#else
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return (((uint8_t*)&a)[0] << 0) |
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(((uint8_t*)&a)[1] << 8) |
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(((uint8_t*)&a)[2] << 16) |
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(((uint8_t*)&a)[3] << 24);
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#endif
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}
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static inline uint32_t lfs_tole32(uint32_t a) {
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return lfs_fromle32(a);
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}
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// Convert between 16-bit little-endian and native order
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static inline uint16_t lfs_fromle16(uint16_t a) {
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#if !defined(LFS_NO_INTRINSICS) && ( \
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(defined( BYTE_ORDER ) && BYTE_ORDER == ORDER_LITTLE_ENDIAN ) || \
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(defined(__BYTE_ORDER ) && __BYTE_ORDER == __ORDER_LITTLE_ENDIAN ) || \
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(defined(__BYTE_ORDER__) && __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__))
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return a;
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#elif !defined(LFS_NO_INTRINSICS) && ( \
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(defined( BYTE_ORDER ) && BYTE_ORDER == ORDER_BIG_ENDIAN ) || \
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(defined(__BYTE_ORDER ) && __BYTE_ORDER == __ORDER_BIG_ENDIAN ) || \
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(defined(__BYTE_ORDER__) && __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__))
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return __builtin_bswap16(a);
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#else
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return (((uint8_t*)&a)[0] << 0) |
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(((uint8_t*)&a)[1] << 8);
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#endif
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}
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static inline uint16_t lfs_tole16(uint16_t a) {
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return lfs_fromle16(a);
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}
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// Calculate CRC-32 with polynomial = 0x04c11db7
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uint32_t lfs_crc(uint32_t crc, const void *buffer, size_t size);
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// Allocate memory, only used if buffers are not provided to littlefs
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static inline void *lfs_malloc(size_t size) {
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#ifndef LFS_NO_MALLOC
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return malloc(size);
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#else
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(void)size;
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return NULL;
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#endif
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}
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// Deallocate memory, only used if buffers are not provided to littlefs
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static inline void lfs_free(void *p) {
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#ifndef LFS_NO_MALLOC
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free(p);
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#else
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(void)p;
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#endif
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}
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#ifdef __cplusplus
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} /* extern "C" */
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#endif
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#endif
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#endif
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