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  }