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Changed lfs_crc to match more common API

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In looking at the common CRC APIs out there, this seemed the most
common. At least more common than the current modified-in-place pointer
API. It also seems to have a slightly better code footprint. I'm blaming
pointer optimization issues.

One downside is that lfs_crc can't report errors, however it was already
assumed that lfs_crc can not error.
This commit is contained in:
Christopher Haster
2018-08-07 14:59:44 -05:00
parent 3b3981eb74
commit 10f45ac02f
3 changed files with 17 additions and 15 deletions
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22
lfs.c
View File

@@ -121,7 +121,7 @@ static int lfs_cache_crc(lfs_t *lfs,
return err; return err;
} }
lfs_crc(crc, &c, 1); *crc = lfs_crc(*crc, &c, 1);
} }
return 0; return 0;
@@ -236,7 +236,7 @@ static int lfs_bd_cmp(lfs_t *lfs, lfs_block_t block,
return lfs_cache_cmp(lfs, NULL, &lfs->rcache, block, off, buffer, size); return lfs_cache_cmp(lfs, NULL, &lfs->rcache, block, off, buffer, size);
} }
static int lfs_bd_crc(lfs_t *lfs, lfs_block_t block, static int lfs_bd_crc32(lfs_t *lfs, lfs_block_t block,
lfs_off_t off, lfs_size_t size, uint32_t *crc) { lfs_off_t off, lfs_size_t size, uint32_t *crc) {
return lfs_cache_crc(lfs, NULL, &lfs->rcache, block, off, size, crc); return lfs_cache_crc(lfs, NULL, &lfs->rcache, block, off, size, crc);
} }
@@ -562,7 +562,7 @@ static int lfs_commit_attr(lfs_t *lfs, struct lfs_commit *commit,
// write out tag // write out tag
uint32_t ntag = lfs_tole32((tag & 0x7fffffff) ^ commit->ptag); uint32_t ntag = lfs_tole32((tag & 0x7fffffff) ^ commit->ptag);
lfs_crc(&commit->crc, &ntag, sizeof(ntag)); commit->crc = lfs_crc(commit->crc, &ntag, sizeof(ntag));
int err = lfs_bd_prog(lfs, commit->block, commit->off, int err = lfs_bd_prog(lfs, commit->block, commit->off,
&ntag, sizeof(ntag)); &ntag, sizeof(ntag));
if (err) { if (err) {
@@ -572,7 +572,7 @@ static int lfs_commit_attr(lfs_t *lfs, struct lfs_commit *commit,
if (!(tag & 0x80000000)) { if (!(tag & 0x80000000)) {
// from memory // from memory
lfs_crc(&commit->crc, buffer, size); commit->crc = lfs_crc(commit->crc, buffer, size);
err = lfs_bd_prog(lfs, commit->block, commit->off, buffer, size); err = lfs_bd_prog(lfs, commit->block, commit->off, buffer, size);
if (err) { if (err) {
return err; return err;
@@ -588,7 +588,7 @@ static int lfs_commit_attr(lfs_t *lfs, struct lfs_commit *commit,
return err; return err;
} }
lfs_crc(&commit->crc, &dat, 1); commit->crc = lfs_crc(commit->crc, &dat, 1);
err = lfs_bd_prog(lfs, commit->block, commit->off+i, &dat, 1); err = lfs_bd_prog(lfs, commit->block, commit->off+i, &dat, 1);
if (err) { if (err) {
return err; return err;
@@ -714,7 +714,7 @@ static int lfs_commit_crc(lfs_t *lfs, struct lfs_commit *commit) {
// write out crc // write out crc
uint32_t footer[2]; uint32_t footer[2];
footer[0] = lfs_tole32(tag ^ commit->ptag); footer[0] = lfs_tole32(tag ^ commit->ptag);
lfs_crc(&commit->crc, &footer[0], sizeof(footer[0])); commit->crc = lfs_crc(commit->crc, &footer[0], sizeof(footer[0]));
footer[1] = lfs_tole32(commit->crc); footer[1] = lfs_tole32(commit->crc);
err = lfs_bd_prog(lfs, commit->block, commit->off, footer, sizeof(footer)); err = lfs_bd_prog(lfs, commit->block, commit->off, footer, sizeof(footer));
if (err) { if (err) {
@@ -731,7 +731,7 @@ static int lfs_commit_crc(lfs_t *lfs, struct lfs_commit *commit) {
// successful commit, check checksum to make sure // successful commit, check checksum to make sure
uint32_t crc = 0xffffffff; uint32_t crc = 0xffffffff;
err = lfs_bd_crc(lfs, commit->block, commit->begin, err = lfs_bd_crc32(lfs, commit->block, commit->begin,
commit->off-lfs_tag_size(tag)-commit->begin, &crc); commit->off-lfs_tag_size(tag)-commit->begin, &crc);
if (err) { if (err) {
return err; return err;
@@ -810,7 +810,7 @@ static int32_t lfs_dir_fetchmatch(lfs_t *lfs,
uint32_t crc = 0xffffffff; uint32_t crc = 0xffffffff;
dir->rev = lfs_tole32(rev[0]); dir->rev = lfs_tole32(rev[0]);
lfs_crc(&crc, &dir->rev, sizeof(dir->rev)); crc = lfs_crc(crc, &dir->rev, sizeof(dir->rev));
dir->rev = lfs_fromle32(dir->rev); dir->rev = lfs_fromle32(dir->rev);
dir->off = 0; dir->off = 0;
@@ -835,7 +835,7 @@ static int32_t lfs_dir_fetchmatch(lfs_t *lfs,
return err; return err;
} }
lfs_crc(&crc, &tag, sizeof(tag)); crc = lfs_crc(crc, &tag, sizeof(tag));
tag = lfs_fromle32(tag) ^ ptag; tag = lfs_fromle32(tag) ^ ptag;
// next commit not yet programmed // next commit not yet programmed
@@ -879,7 +879,7 @@ static int32_t lfs_dir_fetchmatch(lfs_t *lfs,
dir->locals = templocals; dir->locals = templocals;
crc = 0xffffffff; crc = 0xffffffff;
} else { } else {
err = lfs_bd_crc(lfs, dir->pair[0], err = lfs_bd_crc32(lfs, dir->pair[0],
off+sizeof(tag), lfs_tag_size(tag), &crc); off+sizeof(tag), lfs_tag_size(tag), &crc);
if (err) { if (err) {
if (err == LFS_ERR_CORRUPT) { if (err == LFS_ERR_CORRUPT) {
@@ -1062,7 +1062,7 @@ static int lfs_dir_compact(lfs_t *lfs,
// write out header // write out header
uint32_t crc = 0xffffffff; uint32_t crc = 0xffffffff;
uint32_t rev = lfs_tole32(dir->rev); uint32_t rev = lfs_tole32(dir->rev);
lfs_crc(&crc, &rev, sizeof(rev)); crc = lfs_crc(crc, &rev, sizeof(rev));
err = lfs_bd_prog(lfs, dir->pair[1], 0, &rev, sizeof(rev)); err = lfs_bd_prog(lfs, dir->pair[1], 0, &rev, sizeof(rev));
if (err) { if (err) {
if (err == LFS_ERR_CORRUPT) { if (err == LFS_ERR_CORRUPT) {

8
lfs_util.c
View File

@@ -11,7 +11,7 @@
// Software CRC implementation with small lookup table // Software CRC implementation with small lookup table
void lfs_crc(uint32_t *restrict crc, const void *buffer, size_t size) { uint32_t lfs_crc(uint32_t crc, const void *buffer, size_t size) {
static const uint32_t rtable[16] = { static const uint32_t rtable[16] = {
0x00000000, 0x1db71064, 0x3b6e20c8, 0x26d930ac, 0x00000000, 0x1db71064, 0x3b6e20c8, 0x26d930ac,
0x76dc4190, 0x6b6b51f4, 0x4db26158, 0x5005713c, 0x76dc4190, 0x6b6b51f4, 0x4db26158, 0x5005713c,
@@ -22,9 +22,11 @@ void lfs_crc(uint32_t *restrict crc, const void *buffer, size_t size) {
const uint8_t *data = buffer; const uint8_t *data = buffer;
for (size_t i = 0; i < size; i++) { for (size_t i = 0; i < size; i++) {
*crc = (*crc >> 4) ^ rtable[(*crc ^ (data[i] >> 0)) & 0xf]; crc = (crc >> 4) ^ rtable[(crc ^ (data[i] >> 0)) & 0xf];
*crc = (*crc >> 4) ^ rtable[(*crc ^ (data[i] >> 4)) & 0xf]; crc = (crc >> 4) ^ rtable[(crc ^ (data[i] >> 4)) & 0xf];
} }
return crc;
} }

2
lfs_util.h
View File

@@ -187,7 +187,7 @@ static inline uint32_t lfs_alignup(uint32_t a, uint32_t alignment) {
} }
// Calculate CRC-32 with polynomial = 0x04c11db7 // Calculate CRC-32 with polynomial = 0x04c11db7
void lfs_crc(uint32_t *crc, const void *buffer, size_t size); uint32_t lfs_crc(uint32_t crc, const void *buffer, size_t size);
// Allocate memory, only used if buffers are not provided to littlefs // Allocate memory, only used if buffers are not provided to littlefs
static inline void *lfs_malloc(size_t size) { static inline void *lfs_malloc(size_t size) {