1
2 /*
3 * Copyright (C) Igor Sysoev
4 */
5
6
7 #ifndef _NGX_CRC32_H_INCLUDED_
8 #define _NGX_CRC32_H_INCLUDED_
9
10
11 #include <ngx_config.h>
12 #include <ngx_core.h>
13
14
15 extern uint32_t *ngx_crc32_table_short;
16 extern uint32_t ngx_crc32_table256[];
17
18
19 static ngx_inline uint32_t
20 ngx_crc32_short(u_char *p, size_t len)
21 {
22 u_char c;
23 uint32_t crc;
24
25 crc = 0xffffffff;
26
27 while (len--) {
28 c = *p++;
29 crc = ngx_crc32_table_short[(crc ^ (c & 0xf)) & 0xf] ^ (crc >> 4);
30 crc = ngx_crc32_table_short[(crc ^ (c >> 4)) & 0xf] ^ (crc >> 4);
31 }
32
33 return crc ^ 0xffffffff;
34 }
35
36
37 static ngx_inline uint32_t
38 ngx_crc32_long(u_char *p, size_t len)
39 {
40 uint32_t crc;
41
42 crc = 0xffffffff;
43
44 while (len--) {
45 crc = ngx_crc32_table256[(crc ^ *p++) & 0xff] ^ (crc >> 8);
46 }
47
48 return crc ^ 0xffffffff;
49 }
50
51
52 #define ngx_crc32_init(crc) \
53 crc = 0xffffffff
54
55
56 static ngx_inline void
57 ngx_crc32_update(uint32_t *crc, u_char *p, size_t len)
58 {
59 uint32_t c;
60
61 c = *crc;
62
63 while (len--) {
64 c = ngx_crc32_table256[(c ^ *p++) & 0xff] ^ (c >> 8);
65 }
66
67 *crc = c;
68 }
69
70
71 #define ngx_crc32_final(crc) \
72 crc ^= 0xffffffff
73
74
75 ngx_int_t ngx_crc32_table_init(void);
76
77
78 #endif /* _NGX_CRC32_H_INCLUDED_ */
79
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