1///////////////////////////////////////////////////////////////////////////////
2//
3/// \file       crc64_tablegen.c
4/// \brief      Generate crc64_table_le.h and crc64_table_be.h
5///
6/// Compiling: gcc -std=c99 -o crc64_tablegen crc64_tablegen.c
7/// Add -DWORDS_BIGENDIAN to generate big endian table.
8//
9//  Author:     Lasse Collin
10//
11//  This file has been put into the public domain.
12//  You can do whatever you want with this file.
13//
14///////////////////////////////////////////////////////////////////////////////
15
16#include <stdio.h>
17#include "../../common/tuklib_integer.h"
18
19
20static uint64_t crc64_table[4][256];
21
22
23extern void
24init_crc64_table(void)
25{
26	static const uint64_t poly64 = UINT64_C(0xC96C5795D7870F42);
27
28	for (size_t s = 0; s < 4; ++s) {
29		for (size_t b = 0; b < 256; ++b) {
30			uint64_t r = s == 0 ? b : crc64_table[s - 1][b];
31
32			for (size_t i = 0; i < 8; ++i) {
33				if (r & 1)
34					r = (r >> 1) ^ poly64;
35				else
36					r >>= 1;
37			}
38
39			crc64_table[s][b] = r;
40		}
41	}
42
43#ifdef WORDS_BIGENDIAN
44	for (size_t s = 0; s < 4; ++s)
45		for (size_t b = 0; b < 256; ++b)
46			crc64_table[s][b] = bswap64(crc64_table[s][b]);
47#endif
48
49	return;
50}
51
52
53static void
54print_crc64_table(void)
55{
56	printf("/* This file has been automatically generated by "
57			"crc64_tablegen.c. */\n\n"
58			"const uint64_t lzma_crc64_table[4][256] = {\n\t{");
59
60	for (size_t s = 0; s < 4; ++s) {
61		for (size_t b = 0; b < 256; ++b) {
62			if ((b % 2) == 0)
63				printf("\n\t\t");
64
65			printf("UINT64_C(0x%016" PRIX64 ")",
66					crc64_table[s][b]);
67
68			if (b != 255)
69				printf(",%s", (b+1) % 2 == 0 ? "" : " ");
70		}
71
72		if (s == 3)
73			printf("\n\t}\n};\n");
74		else
75			printf("\n\t}, {");
76	}
77
78	return;
79}
80
81
82int
83main(void)
84{
85	init_crc64_table();
86	print_crc64_table();
87	return 0;
88}
89