pcompress/lzma/crc32_tablegen.c
2012-05-28 20:19:29 +05:30

117 lines
2.2 KiB
C

///////////////////////////////////////////////////////////////////////////////
//
/// \file crc32_tablegen.c
/// \brief Generate crc32_table_le.h and crc32_table_be.h
///
/// Compiling: gcc -std=c99 -o crc32_tablegen crc32_tablegen.c
/// Add -DWORDS_BIGENDIAN to generate big endian table.
/// Add -DLZ_HASH_TABLE to generate lz_encoder_hash_table.h (little endian).
//
// Author: Lasse Collin
//
// This file has been put into the public domain.
// You can do whatever you want with this file.
//
///////////////////////////////////////////////////////////////////////////////
#include <stdio.h>
#include "../../common/tuklib_integer.h"
static uint32_t crc32_table[8][256];
static void
init_crc32_table(void)
{
static const uint32_t poly32 = UINT32_C(0xEDB88320);
for (size_t s = 0; s < 8; ++s) {
for (size_t b = 0; b < 256; ++b) {
uint32_t r = s == 0 ? b : crc32_table[s - 1][b];
for (size_t i = 0; i < 8; ++i) {
if (r & 1)
r = (r >> 1) ^ poly32;
else
r >>= 1;
}
crc32_table[s][b] = r;
}
}
#ifdef WORDS_BIGENDIAN
for (size_t s = 0; s < 8; ++s)
for (size_t b = 0; b < 256; ++b)
crc32_table[s][b] = bswap32(crc32_table[s][b]);
#endif
return;
}
static void
print_crc32_table(void)
{
printf("/* This file has been automatically generated by "
"crc32_tablegen.c. */\n\n"
"const uint32_t lzma_crc32_table[8][256] = {\n\t{");
for (size_t s = 0; s < 8; ++s) {
for (size_t b = 0; b < 256; ++b) {
if ((b % 4) == 0)
printf("\n\t\t");
printf("0x%08" PRIX32, crc32_table[s][b]);
if (b != 255)
printf(",%s", (b+1) % 4 == 0 ? "" : " ");
}
if (s == 7)
printf("\n\t}\n};\n");
else
printf("\n\t}, {");
}
return;
}
static void
print_lz_table(void)
{
printf("/* This file has been automatically generated by "
"crc32_tablegen.c. */\n\n"
"const uint32_t lzma_lz_hash_table[256] = {");
for (size_t b = 0; b < 256; ++b) {
if ((b % 4) == 0)
printf("\n\t");
printf("0x%08" PRIX32, crc32_table[0][b]);
if (b != 255)
printf(",%s", (b+1) % 4 == 0 ? "" : " ");
}
printf("\n};\n");
return;
}
int
main(void)
{
init_crc32_table();
#ifdef LZ_HASH_TABLE
print_lz_table();
#else
print_crc32_table();
#endif
return 0;
}