0
|
1
|
|
2 /*
|
|
3 * Copyright (C) Igor Sysoev
|
|
4 */
|
|
5
|
|
6
|
|
7 #ifndef _NGX_CRC_H_INCLUDED_
|
|
8 #define _NGX_CRC_H_INCLUDED_
|
|
9
|
|
10
|
250
|
11 #include <ngx_config.h>
|
|
12 #include <ngx_core.h>
|
|
13
|
|
14
|
0
|
15 /* 32-bit crc16 */
|
|
16
|
248
|
17 static ngx_inline uint32_t
|
250
|
18 ngx_crc(u_char *data, size_t len)
|
0
|
19 {
|
|
20 uint32_t sum;
|
|
21
|
|
22 for (sum = 0; len; len--) {
|
|
23
|
|
24 /*
|
248
|
25 * gcc 2.95.2 x86 and icc 7.1.006 compile
|
|
26 * that operator into the single "rol" opcode,
|
0
|
27 * msvc 6.0sp2 compiles it into four opcodes.
|
|
28 */
|
|
29 sum = sum >> 1 | sum << 31;
|
|
30
|
|
31 sum += *data++;
|
|
32 }
|
|
33
|
|
34 return sum;
|
|
35 }
|
|
36
|
|
37
|
|
38 #endif /* _NGX_CRC_H_INCLUDED_ */
|