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| author | Denys Vlasenko | 2010-10-27 15:26:45 +0200 |
|---|---|---|
| committer | Denys Vlasenko | 2010-10-27 15:26:45 +0200 |
| commit | 9ce642f9746dfc29d119d0680b769677e3ea6da6 (patch) | |
| tree | f8d2bcd08c691979058b610b32573a742a3e3024 /libbb/crc32.c | |
| parent | dd88ba88f5082b1785539b1fb87af7320515b8c9 (diff) | |
| download | busybox-9ce642f9746dfc29d119d0680b769677e3ea6da6.zip busybox-9ce642f9746dfc29d119d0680b769677e3ea6da6.tar.gz | |
libbb: introduce and use common crc32 routine
function old new delta
crc32_block_endian1 - 37 +37
crc32_block_endian0 - 34 +34
global_crc32_table - 8 +8
file_read 82 87 +5
gzip_main 211 214 +3
xz_crc32 40 35 -5
crc32_table 8 - -8
calculate_gunzip_crc 54 34 -20
lzo_crc32 54 25 -29
cksum_main 298 211 -87
------------------------------------------------------------------------------
(add/remove: 3/1 grow/shrink: 2/4 up/down: 87/-149) Total: -62 bytes
Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
Diffstat (limited to 'libbb/crc32.c')
| -rw-r--r-- | libbb/crc32.c | 24 |
1 files changed, 24 insertions, 0 deletions
diff --git a/libbb/crc32.c b/libbb/crc32.c index 520b1ff..2cc6ea7 100644 --- a/libbb/crc32.c +++ b/libbb/crc32.c @@ -18,6 +18,8 @@ #include "libbb.h" +uint32_t *global_crc32_table; + uint32_t* FAST_FUNC crc32_filltable(uint32_t *crc_table, int endian) { uint32_t polynomial = endian ? 0x04c11db7 : 0xedb88320; @@ -40,3 +42,25 @@ uint32_t* FAST_FUNC crc32_filltable(uint32_t *crc_table, int endian) return crc_table - 256; } + +uint32_t FAST_FUNC crc32_block_endian1(uint32_t val, const void *buf, unsigned len, uint32_t *crc_table) +{ + const void *end = (uint8_t*)buf + len; + + while (buf != end) { + val = (val << 8) ^ crc_table[(val >> 24) ^ *(uint8_t*)buf]; + buf = (uint8_t*)buf + 1; + } + return val; +} + +uint32_t FAST_FUNC crc32_block_endian0(uint32_t val, const void *buf, unsigned len, uint32_t *crc_table) +{ + const void *end = (uint8_t*)buf + len; + + while (buf != end) { + val = crc_table [(uint8_t)val ^ *(uint8_t*)buf] ^ (val >> 8); + buf = (uint8_t*)buf + 1; + } + return val; +} |