]>
Commit | Line | Data |
---|---|---|
bd20f8f4 | 1 | //----------------------------------------------------------------------------- |
2 | // This code is licensed to you under the terms of the GNU GPL, version 2 or, | |
3 | // at your option, any later version. See the LICENSE.txt file for the text of | |
4 | // the license. | |
5 | //----------------------------------------------------------------------------- | |
6 | // Generic CRC calculation code. | |
7 | //----------------------------------------------------------------------------- | |
68d9d60a | 8 | #include "crc.h" |
73d04bb4 | 9 | #include <stdint.h> |
10 | #include <stddef.h> | |
68d9d60a | 11 | |
12 | void crc_init(crc_t *crc, int order, uint32_t polynom, uint32_t initial_value, uint32_t final_xor) | |
13 | { | |
14 | crc->order = order; | |
15 | crc->polynom = polynom; | |
16 | crc->initial_value = initial_value; | |
17 | crc->final_xor = final_xor; | |
18 | crc->mask = (1L<<order)-1; | |
19 | crc_clear(crc); | |
20 | } | |
21 | ||
22 | void crc_update(crc_t *crc, uint32_t data, int data_width) | |
23 | { | |
24 | int i; | |
25 | for(i=0; i<data_width; i++) { | |
26 | int oldstate = crc->state; | |
27 | crc->state = crc->state >> 1; | |
28 | if( (oldstate^data) & 1 ) { | |
29 | crc->state ^= crc->polynom; | |
30 | } | |
31 | data >>= 1; | |
32 | } | |
33 | } | |
34 | ||
35 | void crc_clear(crc_t *crc) | |
36 | { | |
37 | crc->state = crc->initial_value & crc->mask; | |
38 | } | |
39 | ||
40 | uint32_t crc_finish(crc_t *crc) | |
41 | { | |
42 | return ( crc->state ^ crc->final_xor ) & crc->mask; | |
43 | } | |
73d04bb4 | 44 | |
e74fc2ec | 45 | //credits to iceman |
46 | uint32_t CRC8Maxim(uint8_t *buff, size_t size) | |
73d04bb4 | 47 | { |
48 | crc_t crc; | |
49 | crc_init(&crc, 9, 0x8c, 0x00, 0x00); | |
50 | crc_clear(&crc); | |
51 | ||
52 | for (size_t i=0; i < size; ++i){ | |
53 | crc_update(&crc, buff[i], 8); | |
54 | } | |
55 | return crc_finish(&crc); | |
56 | } |