1 /*
2 ===========================================================================
3 Copyright (C) 1999 - 2005, Id Software, Inc.
4 Copyright (C) 2000 - 2013, Raven Software, Inc.
5 Copyright (C) 2001 - 2013, Activision, Inc.
6 Copyright (C) 2013 - 2015, OpenJK contributors
7
8 This file is part of the OpenJK source code.
9
10 OpenJK is free software; you can redistribute it and/or modify it
11 under the terms of the GNU General Public License version 2 as
12 published by the Free Software Foundation.
13
14 This program is distributed in the hope that it will be useful,
15 but WITHOUT ANY WARRANTY; without even the implied warranty of
16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 GNU General Public License for more details.
18
19 You should have received a copy of the GNU General Public License
20 along with this program; if not, see <http://www.gnu.org/licenses/>.
21 ===========================================================================
22 */
23
24 /*****************************************************************************
25 * name: l_crc.c
26 *
27 * desc: CRC calculation
28 *
29 * $Archive: /MissionPack/CODE/botlib/l_crc.c $
30 * $Author: Raduffy $
31 * $Revision: 1 $
32 * $Modtime: 12/20/99 8:42p $
33 * $Date: 3/08/00 11:28a $
34 *
35 *****************************************************************************/
36
37 #include <stdlib.h>
38 #include <stdio.h>
39 #include <string.h>
40
41 #include "qcommon/q_shared.h"
42 #include "botlib.h"
43 #include "be_interface.h" //for botimport.Print
44 #include "l_crc.h"
45
46
47 // FIXME: byte swap?
48
49 // this is a 16 bit, non-reflected CRC using the polynomial 0x1021
50 // and the initial and final xor values shown below... in other words, the
51 // CCITT standard CRC used by XMODEM
52
53 #define CRC_INIT_VALUE 0xffff
54 #define CRC_XOR_VALUE 0x0000
55
56 unsigned short crctable[257] =
57 {
58 0x0000, 0x1021, 0x2042, 0x3063, 0x4084, 0x50a5, 0x60c6, 0x70e7,
59 0x8108, 0x9129, 0xa14a, 0xb16b, 0xc18c, 0xd1ad, 0xe1ce, 0xf1ef,
60 0x1231, 0x0210, 0x3273, 0x2252, 0x52b5, 0x4294, 0x72f7, 0x62d6,
61 0x9339, 0x8318, 0xb37b, 0xa35a, 0xd3bd, 0xc39c, 0xf3ff, 0xe3de,
62 0x2462, 0x3443, 0x0420, 0x1401, 0x64e6, 0x74c7, 0x44a4, 0x5485,
63 0xa56a, 0xb54b, 0x8528, 0x9509, 0xe5ee, 0xf5cf, 0xc5ac, 0xd58d,
64 0x3653, 0x2672, 0x1611, 0x0630, 0x76d7, 0x66f6, 0x5695, 0x46b4,
65 0xb75b, 0xa77a, 0x9719, 0x8738, 0xf7df, 0xe7fe, 0xd79d, 0xc7bc,
66 0x48c4, 0x58e5, 0x6886, 0x78a7, 0x0840, 0x1861, 0x2802, 0x3823,
67 0xc9cc, 0xd9ed, 0xe98e, 0xf9af, 0x8948, 0x9969, 0xa90a, 0xb92b,
68 0x5af5, 0x4ad4, 0x7ab7, 0x6a96, 0x1a71, 0x0a50, 0x3a33, 0x2a12,
69 0xdbfd, 0xcbdc, 0xfbbf, 0xeb9e, 0x9b79, 0x8b58, 0xbb3b, 0xab1a,
70 0x6ca6, 0x7c87, 0x4ce4, 0x5cc5, 0x2c22, 0x3c03, 0x0c60, 0x1c41,
71 0xedae, 0xfd8f, 0xcdec, 0xddcd, 0xad2a, 0xbd0b, 0x8d68, 0x9d49,
72 0x7e97, 0x6eb6, 0x5ed5, 0x4ef4, 0x3e13, 0x2e32, 0x1e51, 0x0e70,
73 0xff9f, 0xefbe, 0xdfdd, 0xcffc, 0xbf1b, 0xaf3a, 0x9f59, 0x8f78,
74 0x9188, 0x81a9, 0xb1ca, 0xa1eb, 0xd10c, 0xc12d, 0xf14e, 0xe16f,
75 0x1080, 0x00a1, 0x30c2, 0x20e3, 0x5004, 0x4025, 0x7046, 0x6067,
76 0x83b9, 0x9398, 0xa3fb, 0xb3da, 0xc33d, 0xd31c, 0xe37f, 0xf35e,
77 0x02b1, 0x1290, 0x22f3, 0x32d2, 0x4235, 0x5214, 0x6277, 0x7256,
78 0xb5ea, 0xa5cb, 0x95a8, 0x8589, 0xf56e, 0xe54f, 0xd52c, 0xc50d,
79 0x34e2, 0x24c3, 0x14a0, 0x0481, 0x7466, 0x6447, 0x5424, 0x4405,
80 0xa7db, 0xb7fa, 0x8799, 0x97b8, 0xe75f, 0xf77e, 0xc71d, 0xd73c,
81 0x26d3, 0x36f2, 0x0691, 0x16b0, 0x6657, 0x7676, 0x4615, 0x5634,
82 0xd94c, 0xc96d, 0xf90e, 0xe92f, 0x99c8, 0x89e9, 0xb98a, 0xa9ab,
83 0x5844, 0x4865, 0x7806, 0x6827, 0x18c0, 0x08e1, 0x3882, 0x28a3,
84 0xcb7d, 0xdb5c, 0xeb3f, 0xfb1e, 0x8bf9, 0x9bd8, 0xabbb, 0xbb9a,
85 0x4a75, 0x5a54, 0x6a37, 0x7a16, 0x0af1, 0x1ad0, 0x2ab3, 0x3a92,
86 0xfd2e, 0xed0f, 0xdd6c, 0xcd4d, 0xbdaa, 0xad8b, 0x9de8, 0x8dc9,
87 0x7c26, 0x6c07, 0x5c64, 0x4c45, 0x3ca2, 0x2c83, 0x1ce0, 0x0cc1,
88 0xef1f, 0xff3e, 0xcf5d, 0xdf7c, 0xaf9b, 0xbfba, 0x8fd9, 0x9ff8,
89 0x6e17, 0x7e36, 0x4e55, 0x5e74, 0x2e93, 0x3eb2, 0x0ed1, 0x1ef0
90 };
91
92 //===========================================================================
93 //
94 // Parameter: -
95 // Returns: -
96 // Changes Globals: -
97 //===========================================================================
CRC_Init(unsigned short * crcvalue)98 void CRC_Init(unsigned short *crcvalue)
99 {
100 *crcvalue = CRC_INIT_VALUE;
101 } //end of the function CRC_Init
102 //===========================================================================
103 //
104 // Parameter: -
105 // Returns: -
106 // Changes Globals: -
107 //===========================================================================
CRC_ProcessByte(unsigned short * crcvalue,byte data)108 void CRC_ProcessByte(unsigned short *crcvalue, byte data)
109 {
110 *crcvalue = (*crcvalue << 8) ^ crctable[(*crcvalue >> 8) ^ data];
111 } //end of the function CRC_ProcessByte
112 //===========================================================================
113 //
114 // Parameter: -
115 // Returns: -
116 // Changes Globals: -
117 //===========================================================================
CRC_Value(unsigned short crcvalue)118 unsigned short CRC_Value(unsigned short crcvalue)
119 {
120 return crcvalue ^ CRC_XOR_VALUE;
121 } //end of the function CRC_Value
122 //===========================================================================
123 //
124 // Parameter: -
125 // Returns: -
126 // Changes Globals: -
127 //===========================================================================
CRC_ProcessString(unsigned char * data,int length)128 unsigned short CRC_ProcessString(unsigned char *data, int length)
129 {
130 unsigned short crcvalue;
131 int i, ind;
132
133 CRC_Init(&crcvalue);
134
135 for (i = 0; i < length; i++)
136 {
137 ind = (crcvalue >> 8) ^ data[i];
138 if (ind < 0 || ind > 256) ind = 0;
139 crcvalue = (crcvalue << 8) ^ crctable[ind];
140 } //end for
141 return CRC_Value(crcvalue);
142 } //end of the function CRC_ProcessString
143 //===========================================================================
144 //
145 // Parameter: -
146 // Returns: -
147 // Changes Globals: -
148 //===========================================================================
CRC_ContinueProcessString(unsigned short * crc,char * data,int length)149 void CRC_ContinueProcessString(unsigned short *crc, char *data, int length)
150 {
151 int i;
152
153 for (i = 0; i < length; i++)
154 {
155 *crc = (*crc << 8) ^ crctable[(*crc >> 8) ^ data[i]];
156 } //end for
157 } //end of the function CRC_ProcessString
158