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
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
|
#include <stdio.h>
#include "crc32defs.h"
#include <inttypes.h>
#define ENTRIES_PER_LINE 4
#define LE_TABLE_SIZE (1 << CRC_LE_BITS)
#define BE_TABLE_SIZE (1 << CRC_BE_BITS)
static uint32_t crc32table_le[4][256];
static uint32_t crc32table_be[4][256];
/**
* crc32init_le() - allocate and initialize LE table data
*
* crc is the crc of the byte i; other entries are filled in based on the
* fact that crctable[i^j] = crctable[i] ^ crctable[j].
*
*/
static void crc32init_le(void)
{
unsigned i, j;
uint32_t crc = 1;
crc32table_le[0][0] = 0;
for (i = 1 << (CRC_LE_BITS - 1); i; i >>= 1) {
crc = (crc >> 1) ^ ((crc & 1) ? CRCPOLY_LE : 0);
for (j = 0; j < LE_TABLE_SIZE; j += 2 * i)
crc32table_le[0][i + j] = crc ^ crc32table_le[0][j];
}
for (i = 0; i < LE_TABLE_SIZE; i++) {
crc = crc32table_le[0][i];
for (j = 1; j < 4; j++) {
crc = crc32table_le[0][crc & 0xff] ^ (crc >> 8);
crc32table_le[j][i] = crc;
}
}
}
/**
* crc32init_be() - allocate and initialize BE table data
*/
static void crc32init_be(void)
{
unsigned i, j;
uint32_t crc = 0x80000000;
crc32table_be[0][0] = 0;
for (i = 1; i < BE_TABLE_SIZE; i <<= 1) {
crc = (crc << 1) ^ ((crc & 0x80000000) ? CRCPOLY_BE : 0);
for (j = 0; j < i; j++)
crc32table_be[0][i + j] = crc ^ crc32table_be[0][j];
}
for (i = 0; i < BE_TABLE_SIZE; i++) {
crc = crc32table_be[0][i];
for (j = 1; j < 4; j++) {
crc = crc32table_be[0][(crc >> 24) & 0xff] ^ (crc << 8);
crc32table_be[j][i] = crc;
}
}
}
static void output_table(uint32_t (*table)[256], int len, char *trans)
{
int i, j;
for (j = 0 ; j < 4; j++) {
printf("{");
for (i = 0; i < len - 1; i++) {
if (i % ENTRIES_PER_LINE == 0)
printf("\n");
printf("%s(0x%8.8xL), ", trans, table[j][i]);
}
printf("%s(0x%8.8xL)},\n", trans, table[j][len - 1]);
}
}
int main(int argc, char** argv)
{
printf("/* this file is generated - do not edit */\n\n");
if (CRC_LE_BITS > 1) {
crc32init_le();
printf("static const u32 crc32table_le[4][256] = {");
output_table(crc32table_le, LE_TABLE_SIZE, "tole");
printf("};\n");
}
if (CRC_BE_BITS > 1) {
crc32init_be();
printf("static const u32 crc32table_be[4][256] = {");
output_table(crc32table_be, BE_TABLE_SIZE, "tobe");
printf("};\n");
}
return 0;
}
|
