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
|
|
11 /* 32-bit crc16 */
|
|
12
|
16
|
13 static ngx_inline uint32_t ngx_crc(char *data, size_t len)
|
0
|
14 {
|
|
15 uint32_t sum;
|
|
16
|
|
17 for (sum = 0; len; len--) {
|
|
18
|
|
19 /*
|
|
20 * gcc 2.95.2 x86 and icc 7.1.006 compile that operator
|
|
21 * into the single "rol" opcode.
|
|
22 * msvc 6.0sp2 compiles it into four opcodes.
|
|
23 */
|
|
24 sum = sum >> 1 | sum << 31;
|
|
25
|
|
26 sum += *data++;
|
|
27 }
|
|
28
|
|
29 return sum;
|
|
30 }
|
|
31
|
|
32
|
|
33 #endif /* _NGX_CRC_H_INCLUDED_ */
|