crc64_tablegen.c revision 256281
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