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/*
Copyright (C) 1997-2001 Id Software, Inc.
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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
// Created on 25.01.2004 by RST.
package jake2.qcommon;
public class CRC
{
public final static short CRC_INIT_VALUE= (short) 0xffff;
public final static short CRC_XOR_VALUE= (short) 0x0000;
private static int crctable[] = { 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 };
static int CRC_Block(byte start[], int count)
{
short crc= CRC_INIT_VALUE;
int ndx= 0;
while (count-- > 0)
crc= (short) ((crc << 8) ^ crctable[0xff & ((crc >> 8) ^ start[ndx++])]);
// unsigned short
return crc & 0xFFFF;
}
public static void main(String[] args)
{
byte data[]=
{
(byte) 0x71,
(byte) 0xa9,
(byte) 0x05,
(byte) 0xce,
(byte) 0x8d,
(byte) 0x75,
(byte) 0x28,
(byte) 0xc8,
(byte) 0xba,
(byte) 0x97,
(byte) 0x45,
(byte) 0xe9,
(byte) 0x8a,
(byte) 0xe0,
(byte) 0x37,
(byte) 0xbd,
(byte) 0x6c,
(byte) 0x6d,
(byte) 0x67,
(byte) 0x4a,
(byte) 0x21 };
System.out.println("crc:" + (CRC_Block(data, 21) & 0xffff));
System.out.println("----");
for (int n=0; n < 5; n++)
System.out.println("seq:" + (Com.BlockSequenceCRCByte( data,0, 21,n*10) & 0xff));
}
/* c test:
*
* D:\Rene\gamesrc\quake2-3.21\qcommon>crc
* crc=-12353
* ----
* seq:215
* seq:252
* seq:164
* seq:202
* seq:201
*
int main()
{
byte data[21] =
{
0x71,
0xa9,
0x05,
0xce,
0x8d,
0x75,
0x28,
0xc8,
0xba,
0x97,
0x45,
0xe9,
0x8a,
0xe0,
0x37,
0xbd,
0x6c,
0x6d,
0x67,
0x4a, 0x21 };
int n=0;
printf("crc=%d\n", (short) CRC_Block(&data, 21));
printf("----\n");
for (n=0; n < 5; n++)
printf("seq:%d\n", COM_BlockSequenceCRCByte( &data,21, n*10) );
}
*/
}
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