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libbb: introduce and use common crc32 routine

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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>
This commit is contained in:
Denys Vlasenko
2010-10-27 15:26:45 +02:00
parent dd88ba88f5
commit 9ce642f974
9 changed files with 49 additions and 73 deletions
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24
libbb/crc32.c
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@@ -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;
}