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 
20 static uint64_t crc64_table[4][256];
21 
22 
23 extern void
24 init_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 
53 static void
54 print_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 
82 int
83 main(void)
84 {
85 	init_crc64_table();
86 	print_crc64_table();
87 	return 0;
88 }
89