blob: f1d8449c603a72f10a63883b8143303ac0cecf03 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
|
/*
* @copyright Copyright (c) 2016-2020 TOYOTA MOTOR CORPORATION.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <cstdio>
#include "bkup_crc32.h"
#include "bkup_util.h"
/*
* CRC-32C lookup table
*
* Polynomial 0x1EDC6F41
*/
static const uint32_t kBkupCrc32Lookup[4][256] = {
{
},
{
},
{
},
{
}
};
/**
* compute CRC-32C (Slicing-by-4)
*/
uint32_t BkupCrc32(const void *data, size_t length) {
uint32_t crc = 0xFFFFFFFF;
const uint32_t *current = (const uint32_t *)data;
if (data == NULL) {
return -1;
}
while (length >= 4) {
uint32_t one = *current++ ^ crc;
crc = kBkupCrc32Lookup[0][(one >> 24) & 0xFF] ^
kBkupCrc32Lookup[1][(one >> 16) & 0xFF] ^
kBkupCrc32Lookup[2][(one >> 8) & 0xFF] ^
kBkupCrc32Lookup[3][one & 0xFF];
length -= 4;
}
const uint8_t *current_char = (const uint8_t *)current;
while (length-- > 0) {
crc = (crc >> 8) ^ kBkupCrc32Lookup[0][(crc & 0xFF) ^ *current_char++];
}
return ~crc;
}
|
