Mercurial > hg > nginx
comparison src/core/ngx_crc.h @ 201:267ea1d98683
nginx-0.0.1-2003-11-30-23:03:18 import
| author | Igor Sysoev <igor@sysoev.ru> |
|---|---|
| date | Sun, 30 Nov 2003 20:03:18 +0000 |
| parents | |
| children | 0b67be7d4489 |
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| 200:abeaebe0a33c | 201:267ea1d98683 |
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| 1 #ifndef _NGX_CRC_H_INCLUDED_ | |
| 2 #define _NGX_CRC_H_INCLUDED_ | |
| 3 | |
| 4 | |
| 5 /* 32-bit crc16 */ | |
| 6 | |
| 7 ngx_inline static uint32_t ngx_crc(char *data, size_t len) | |
| 8 { | |
| 9 uint32_t sum; | |
| 10 | |
| 11 for (sum = 0; len; len--) { | |
| 12 /* | |
| 13 * gcc 2.95.2 x86 and icc 7.1.006 compile that operator | |
| 14 * into the single rol opcode. | |
| 15 * msvc 6.0sp2 compiles it into four opcodes. | |
| 16 */ | |
| 17 sum = sum >> 1 | sum << 31; | |
| 18 | |
| 19 sum += *data++; | |
| 20 } | |
| 21 | |
| 22 return sum; | |
| 23 } | |
| 24 | |
| 25 | |
| 26 #endif /* _NGX_CRC_H_INCLUDED_ */ |