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/*
===========================================================================
Return to Castle Wolfenstein single player GPL Source Code
Copyright (C) 1999-2010 id Software LLC, a ZeniMax Media company.
This file is part of the Return to Castle Wolfenstein single player GPL Source Code (RTCW SP Source Code).
RTCW SP Source Code 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 3 of the License, or
(at your option) any later version.
RTCW SP Source Code 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 RTCW SP Source Code. If not, see <http://www.gnu.org/licenses/>.
In addition, the RTCW SP Source Code is also subject to certain additional terms. You should have received a copy of these additional terms immediately following the terms and conditions of the GNU General Public License which accompanied the RTCW SP Source Code. If not, please request a copy in writing from id Software at the address below.
If you have questions concerning this license or the applicable additional terms, you may contact in writing id Software LLC, c/o ZeniMax Media Inc., Suite 120, Rockville, Maryland 20850 USA.
===========================================================================
*/
/*****************************************************************************
* name: l_crc.c
*
* desc: CRC calculation
*
*
*****************************************************************************/
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include "../qcommon/q_shared.h"
#include "botlib.h"
#include "be_interface.h" //for botimport.Print
#include "l_crc.h"
// FIXME: byte swap?
// this is a 16 bit, non-reflected CRC using the polynomial 0x1021
// and the initial and final xor values shown below... in other words, the
// CCITT standard CRC used by XMODEM
#define CRC_INIT_VALUE 0xffff
#define CRC_XOR_VALUE 0x0000
unsigned short crctable[257] =
{
0x0000, 0x1021, 0x2042, 0x3063, 0x4084, 0x50a5, 0x60c6, 0x70e7,
0x8108, 0x9129, 0xa14a, 0xb16b, 0xc18c, 0xd1ad, 0xe1ce, 0xf1ef,
0x1231, 0x0210, 0x3273, 0x2252, 0x52b5, 0x4294, 0x72f7, 0x62d6,
0x9339, 0x8318, 0xb37b, 0xa35a, 0xd3bd, 0xc39c, 0xf3ff, 0xe3de,
0x2462, 0x3443, 0x0420, 0x1401, 0x64e6, 0x74c7, 0x44a4, 0x5485,
0xa56a, 0xb54b, 0x8528, 0x9509, 0xe5ee, 0xf5cf, 0xc5ac, 0xd58d,
0x3653, 0x2672, 0x1611, 0x0630, 0x76d7, 0x66f6, 0x5695, 0x46b4,
0xb75b, 0xa77a, 0x9719, 0x8738, 0xf7df, 0xe7fe, 0xd79d, 0xc7bc,
0x48c4, 0x58e5, 0x6886, 0x78a7, 0x0840, 0x1861, 0x2802, 0x3823,
0xc9cc, 0xd9ed, 0xe98e, 0xf9af, 0x8948, 0x9969, 0xa90a, 0xb92b,
0x5af5, 0x4ad4, 0x7ab7, 0x6a96, 0x1a71, 0x0a50, 0x3a33, 0x2a12,
0xdbfd, 0xcbdc, 0xfbbf, 0xeb9e, 0x9b79, 0x8b58, 0xbb3b, 0xab1a,
0x6ca6, 0x7c87, 0x4ce4, 0x5cc5, 0x2c22, 0x3c03, 0x0c60, 0x1c41,
0xedae, 0xfd8f, 0xcdec, 0xddcd, 0xad2a, 0xbd0b, 0x8d68, 0x9d49,
0x7e97, 0x6eb6, 0x5ed5, 0x4ef4, 0x3e13, 0x2e32, 0x1e51, 0x0e70,
0xff9f, 0xefbe, 0xdfdd, 0xcffc, 0xbf1b, 0xaf3a, 0x9f59, 0x8f78,
0x9188, 0x81a9, 0xb1ca, 0xa1eb, 0xd10c, 0xc12d, 0xf14e, 0xe16f,
0x1080, 0x00a1, 0x30c2, 0x20e3, 0x5004, 0x4025, 0x7046, 0x6067,
0x83b9, 0x9398, 0xa3fb, 0xb3da, 0xc33d, 0xd31c, 0xe37f, 0xf35e,
0x02b1, 0x1290, 0x22f3, 0x32d2, 0x4235, 0x5214, 0x6277, 0x7256,
0xb5ea, 0xa5cb, 0x95a8, 0x8589, 0xf56e, 0xe54f, 0xd52c, 0xc50d,
0x34e2, 0x24c3, 0x14a0, 0x0481, 0x7466, 0x6447, 0x5424, 0x4405,
0xa7db, 0xb7fa, 0x8799, 0x97b8, 0xe75f, 0xf77e, 0xc71d, 0xd73c,
0x26d3, 0x36f2, 0x0691, 0x16b0, 0x6657, 0x7676, 0x4615, 0x5634,
0xd94c, 0xc96d, 0xf90e, 0xe92f, 0x99c8, 0x89e9, 0xb98a, 0xa9ab,
0x5844, 0x4865, 0x7806, 0x6827, 0x18c0, 0x08e1, 0x3882, 0x28a3,
0xcb7d, 0xdb5c, 0xeb3f, 0xfb1e, 0x8bf9, 0x9bd8, 0xabbb, 0xbb9a,
0x4a75, 0x5a54, 0x6a37, 0x7a16, 0x0af1, 0x1ad0, 0x2ab3, 0x3a92,
0xfd2e, 0xed0f, 0xdd6c, 0xcd4d, 0xbdaa, 0xad8b, 0x9de8, 0x8dc9,
0x7c26, 0x6c07, 0x5c64, 0x4c45, 0x3ca2, 0x2c83, 0x1ce0, 0x0cc1,
0xef1f, 0xff3e, 0xcf5d, 0xdf7c, 0xaf9b, 0xbfba, 0x8fd9, 0x9ff8,
0x6e17, 0x7e36, 0x4e55, 0x5e74, 0x2e93, 0x3eb2, 0x0ed1, 0x1ef0,
0x0000 // code reaches element 256
};
//===========================================================================
//
// Parameter: -
// Returns: -
// Changes Globals: -
//===========================================================================
void CRC_Init( unsigned short *crcvalue ) {
*crcvalue = CRC_INIT_VALUE;
} //end of the function CRC_Init
//===========================================================================
//
// Parameter: -
// Returns: -
// Changes Globals: -
//===========================================================================
void CRC_ProcessByte( unsigned short *crcvalue, byte data ) {
*crcvalue = ( *crcvalue << 8 ) ^ crctable[( *crcvalue >> 8 ) ^ data];
} //end of the function CRC_ProcessByte
//===========================================================================
//
// Parameter: -
// Returns: -
// Changes Globals: -
//===========================================================================
unsigned short CRC_Value( unsigned short crcvalue ) {
return crcvalue ^ CRC_XOR_VALUE;
} //end of the function CRC_Value
//===========================================================================
//
// Parameter: -
// Returns: -
// Changes Globals: -
//===========================================================================
unsigned short CRC_ProcessString( unsigned char *data, int length ) {
unsigned short crcvalue;
int i, ind;
CRC_Init( &crcvalue );
for ( i = 0; i < length; i++ )
{
ind = ( crcvalue >> 8 ) ^ data[i];
if ( ind < 0 || ind > 256 ) {
ind = 0;
}
crcvalue = ( crcvalue << 8 ) ^ crctable[ind];
} //end for
return CRC_Value( crcvalue );
} //end of the function CRC_ProcessString
//===========================================================================
//
// Parameter: -
// Returns: -
// Changes Globals: -
//===========================================================================
void CRC_ContinueProcessString( unsigned short *crc, char *data, int length ) {
int i;
for ( i = 0; i < length; i++ )
{
*crc = ( *crc << 8 ) ^ crctable[( *crc >> 8 ) ^ data[i]];
} //end for
} //end of the function CRC_ProcessString
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