/*     crc.c    Copyright (C) Christian Wolff for convergence integrated media.    This program is free software; you can redistribute it and/or modify    it under the terms of the GNU General Public License as published by    the Free Software Foundation; either version 2 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 General Public License for more details.    You should have received a copy of the GNU General Public License    along with this program; if not, write to the Free Software    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.*//*---------------------------------------------------------Cyclic Redundancy Check 16 and 32 BitChristian Wolff, 19990122---------------------------------------------------------*/#define __NO_VERSION__#include "crc.h"unsigned short crc_16_table[256];unsigned long crc_32_table[256];// generate the tables of CRC-16 and CRC-32 remainders for all possible bytesvoid gen_crc_table(){	register int i, j;	register unsigned short crc16;	register unsigned long crc32;	for (i = 0; i < 256; i++) {		crc16 = (unsigned short) i << 8;		crc32 = (unsigned long) i << 24;		for (j = 0; j < 8; j++) {			if (crc16 & 0x8000)				crc16 = (crc16 << 1) ^ POLYNOMIAL_16;			else				crc16 = (crc16 << 1);			if (crc32 & 0x80000000L)				crc32 = (crc32 << 1) ^ POLYNOMIAL_32;			else				crc32 = (crc32 << 1);		}		crc_16_table[i] = crc16;		crc_32_table[i] = crc32;	}}// update the CRC on the data block one byte at a timeunsigned short update_crc_16_block(unsigned short crc,				   char *data_block_ptr,				   int data_block_size){	register int i;	for (i = 0; i < data_block_size; i++)		crc = update_crc_16(crc, *data_block_ptr++);	return crc;}unsigned long update_crc_32_block(unsigned long crc, char *data_block_ptr,				  int data_block_size){	register int i;	for (i = 0; i < data_block_size; i++)		crc = update_crc_32(crc, *data_block_ptr++);	return crc;}