Annotation of embedaddon/nginx/src/core/ngx_crc.h, revision 1.1.1.1
1.1 misho 1:
2: /*
3: * Copyright (C) Igor Sysoev
4: * Copyright (C) Nginx, Inc.
5: */
6:
7:
8: #ifndef _NGX_CRC_H_INCLUDED_
9: #define _NGX_CRC_H_INCLUDED_
10:
11:
12: #include <ngx_config.h>
13: #include <ngx_core.h>
14:
15:
16: /* 32-bit crc16 */
17:
18: static ngx_inline uint32_t
19: ngx_crc(u_char *data, size_t len)
20: {
21: uint32_t sum;
22:
23: for (sum = 0; len; len--) {
24:
25: /*
26: * gcc 2.95.2 x86 and icc 7.1.006 compile
27: * that operator into the single "rol" opcode,
28: * msvc 6.0sp2 compiles it into four opcodes.
29: */
30: sum = sum >> 1 | sum << 31;
31:
32: sum += *data++;
33: }
34:
35: return sum;
36: }
37:
38:
39: #endif /* _NGX_CRC_H_INCLUDED_ */
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