1 #include <stdio.h>
2 #include "crc32c_defs.h"
3 #include <inttypes.h>
4
5 #define ENTRIES_PER_LINE 4
6
7 #if CRC_LE_BITS <= 8
8 #define LE_TABLE_SIZE (1 << CRC_LE_BITS)
9 #else
10 #define LE_TABLE_SIZE 256
11 #endif
12
13 #if CRC_BE_BITS <= 8
14 #define BE_TABLE_SIZE (1 << CRC_BE_BITS)
15 #else
16 #define BE_TABLE_SIZE 256
17 #endif
18
19 static uint32_t crc32ctable_le[8][256];
20 static uint32_t crc32ctable_be[8][256];
21
22 /**
23 * crc32cinit_le() - allocate and initialize LE table data
24 *
25 * crc is the crc of the byte i; other entries are filled in based on the
26 * fact that crctable[i^j] = crctable[i] ^ crctable[j].
27 *
28 */
crc32cinit_le(void)29 static void crc32cinit_le(void)
30 {
31 unsigned i, j;
32 uint32_t crc = 1;
33
34 crc32ctable_le[0][0] = 0;
35
36 for (i = LE_TABLE_SIZE >> 1; i; i >>= 1) {
37 crc = (crc >> 1) ^ ((crc & 1) ? CRCPOLY_LE : 0);
38 for (j = 0; j < LE_TABLE_SIZE; j += 2 * i)
39 crc32ctable_le[0][i + j] = crc ^ crc32ctable_le[0][j];
40 }
41 for (i = 0; i < LE_TABLE_SIZE; i++) {
42 crc = crc32ctable_le[0][i];
43 for (j = 1; j < 8; j++) {
44 crc = crc32ctable_le[0][crc & 0xff] ^ (crc >> 8);
45 crc32ctable_le[j][i] = crc;
46 }
47 }
48 }
49
50 /**
51 * crc32cinit_be() - allocate and initialize BE table data
52 */
crc32cinit_be(void)53 static void crc32cinit_be(void)
54 {
55 unsigned i, j;
56 uint32_t crc = 0x80000000;
57
58 crc32ctable_be[0][0] = 0;
59
60 for (i = 1; i < BE_TABLE_SIZE; i <<= 1) {
61 crc = (crc << 1) ^ ((crc & 0x80000000) ? CRCPOLY_BE : 0);
62 for (j = 0; j < i; j++)
63 crc32ctable_be[0][i + j] = crc ^ crc32ctable_be[0][j];
64 }
65 for (i = 0; i < BE_TABLE_SIZE; i++) {
66 crc = crc32ctable_be[0][i];
67 for (j = 1; j < 8; j++) {
68 crc = crc32ctable_be[0][(crc >> 24) & 0xff] ^
69 (crc << 8);
70 crc32ctable_be[j][i] = crc;
71 }
72 }
73 }
74
output_table(uint32_t table[8][256],int len,char trans)75 static void output_table(uint32_t table[8][256], int len, char trans)
76 {
77 int i, j;
78
79 for (j = 0 ; j < 8; j++) {
80 printf("static const uint32_t t%d_%ce[] = {", j, trans);
81 for (i = 0; i < len - 1; i++) {
82 if ((i % ENTRIES_PER_LINE) == 0)
83 printf("\n");
84 printf("to%ce(0x%8.8xL),", trans, table[j][i]);
85 if ((i % ENTRIES_PER_LINE) != (ENTRIES_PER_LINE - 1))
86 printf(" ");
87 }
88 printf("to%ce(0x%8.8xL)};\n\n", trans, table[j][len - 1]);
89
90 if (trans == 'l') {
91 if ((j+1)*8 >= CRC_LE_BITS)
92 break;
93 } else {
94 if ((j+1)*8 >= CRC_BE_BITS)
95 break;
96 }
97 }
98 }
99
main(int argc,char ** argv)100 int main(int argc, char **argv)
101 {
102 printf("/*\n");
103 printf(" * crc32ctable.h - CRC32c tables\n");
104 printf(" * this file is generated - do not edit\n");
105 printf(" * # gen_crc32ctable > crc32c_table.h\n");
106 printf(" * with\n");
107 printf(" * CRC_LE_BITS = %d\n", CRC_LE_BITS);
108 printf(" * CRC_BE_BITS = %d\n", CRC_BE_BITS);
109 printf(" */\n");
110 printf("#include <stdint.h>\n");
111
112 if (CRC_LE_BITS > 1) {
113 crc32cinit_le();
114 output_table(crc32ctable_le, LE_TABLE_SIZE, 'l');
115 }
116
117 if (CRC_BE_BITS > 1) {
118 crc32cinit_be();
119 output_table(crc32ctable_be, BE_TABLE_SIZE, 'b');
120 }
121
122 return 0;
123 }
124