pcompress/lzma/crc64_tablegen.c

114 lines
2.7 KiB
C
Raw Permalink Normal View History

2013-03-07 14:56:48 +00:00
/*
* This file is a part of Pcompress, a chunked parallel multi-
* algorithm lossless compression and decompression program.
*
* Copyright (C) 2012-2013 Moinak Ghosh. All rights reserved.
* Use is subject to license terms.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 3 of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this program.
* If not, see <http://www.gnu.org/licenses/>.
*
* moinakg@belenix.org, http://moinakg.wordpress.com/
*
*/
2012-05-28 14:49:29 +00:00
///////////////////////////////////////////////////////////////////////////////
//
/// \file crc64_tablegen.c
/// \brief Generate crc64_table_le.h and crc64_table_be.h
///
/// Compiling: gcc -std=c99 -o crc64_tablegen crc64_tablegen.c
/// Add -DWORDS_BIGENDIAN to generate big endian table.
//
// 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 uint64_t crc64_table[4][256];
extern void
init_crc64_table(void)
{
static const uint64_t poly64 = UINT64_C(0xC96C5795D7870F42);
for (size_t s = 0; s < 4; ++s) {
for (size_t b = 0; b < 256; ++b) {
uint64_t r = s == 0 ? b : crc64_table[s - 1][b];
for (size_t i = 0; i < 8; ++i) {
if (r & 1)
r = (r >> 1) ^ poly64;
else
r >>= 1;
}
crc64_table[s][b] = r;
}
}
#ifdef WORDS_BIGENDIAN
for (size_t s = 0; s < 4; ++s)
for (size_t b = 0; b < 256; ++b)
crc64_table[s][b] = bswap64(crc64_table[s][b]);
#endif
return;
}
static void
print_crc64_table(void)
{
printf("/* This file has been automatically generated by "
"crc64_tablegen.c. */\n\n"
"const uint64_t lzma_crc64_table[4][256] = {\n\t{");
for (size_t s = 0; s < 4; ++s) {
for (size_t b = 0; b < 256; ++b) {
if ((b % 2) == 0)
printf("\n\t\t");
printf("UINT64_C(0x%016" PRIX64 ")",
crc64_table[s][b]);
if (b != 255)
printf(",%s", (b+1) % 2 == 0 ? "" : " ");
}
if (s == 3)
printf("\n\t}\n};\n");
else
printf("\n\t}, {");
}
return;
}
int
main(void)
{
init_crc64_table();
print_crc64_table();
return 0;
}