crc32_tablegen.c revision 256281
1/////////////////////////////////////////////////////////////////////////////// 2// 3/// \file crc32_tablegen.c 4/// \brief Generate crc32_table_le.h and crc32_table_be.h 5/// 6/// Compiling: gcc -std=c99 -o crc32_tablegen crc32_tablegen.c 7/// Add -DWORDS_BIGENDIAN to generate big endian table. 8/// Add -DLZ_HASH_TABLE to generate lz_encoder_hash_table.h (little endian). 9// 10// Author: Lasse Collin 11// 12// This file has been put into the public domain. 13// You can do whatever you want with this file. 14// 15/////////////////////////////////////////////////////////////////////////////// 16 17#include <stdio.h> 18#include "../../common/tuklib_integer.h" 19 20 21static uint32_t crc32_table[8][256]; 22 23 24static void 25init_crc32_table(void) 26{ 27 static const uint32_t poly32 = UINT32_C(0xEDB88320); 28 29 for (size_t s = 0; s < 8; ++s) { 30 for (size_t b = 0; b < 256; ++b) { 31 uint32_t r = s == 0 ? b : crc32_table[s - 1][b]; 32 33 for (size_t i = 0; i < 8; ++i) { 34 if (r & 1) 35 r = (r >> 1) ^ poly32; 36 else 37 r >>= 1; 38 } 39 40 crc32_table[s][b] = r; 41 } 42 } 43 44#ifdef WORDS_BIGENDIAN 45 for (size_t s = 0; s < 8; ++s) 46 for (size_t b = 0; b < 256; ++b) 47 crc32_table[s][b] = bswap32(crc32_table[s][b]); 48#endif 49 50 return; 51} 52 53 54static void 55print_crc32_table(void) 56{ 57 printf("/* This file has been automatically generated by " 58 "crc32_tablegen.c. */\n\n" 59 "const uint32_t lzma_crc32_table[8][256] = {\n\t{"); 60 61 for (size_t s = 0; s < 8; ++s) { 62 for (size_t b = 0; b < 256; ++b) { 63 if ((b % 4) == 0) 64 printf("\n\t\t"); 65 66 printf("0x%08" PRIX32, crc32_table[s][b]); 67 68 if (b != 255) 69 printf(",%s", (b+1) % 4 == 0 ? "" : " "); 70 } 71 72 if (s == 7) 73 printf("\n\t}\n};\n"); 74 else 75 printf("\n\t}, {"); 76 } 77 78 return; 79} 80 81 82static void 83print_lz_table(void) 84{ 85 printf("/* This file has been automatically generated by " 86 "crc32_tablegen.c. */\n\n" 87 "const uint32_t lzma_lz_hash_table[256] = {"); 88 89 for (size_t b = 0; b < 256; ++b) { 90 if ((b % 4) == 0) 91 printf("\n\t"); 92 93 printf("0x%08" PRIX32, crc32_table[0][b]); 94 95 if (b != 255) 96 printf(",%s", (b+1) % 4 == 0 ? "" : " "); 97 } 98 99 printf("\n};\n"); 100 101 return; 102} 103 104 105int 106main(void) 107{ 108 init_crc32_table(); 109 110#ifdef LZ_HASH_TABLE 111 print_lz_table(); 112#else 113 print_crc32_table(); 114#endif 115 116 return 0; 117} 118