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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 }