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
19static uint32_t crc32ctable_le[8][256];
20static 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 */
29static 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 */
53static 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
75static 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
100int 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