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  
      21  static uint32_t crc32_table[8][256];
      22  
      23  
      24  static void
      25  init_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  
      54  static void
      55  print_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  
      82  static void
      83  print_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  
     105  int
     106  main(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  }