Annotation of sbbs/smblib/crc16.c, revision 1.1.1.1

1.1       root        1: /* crc16.c */
                      2: 
                      3: /* CCITT 16-bit CRC table and calculation function */
                      4: 
                      5: /* $Id: crc16.c,v 1.3 2004/02/27 02:30:36 rswindell Exp $ */
                      6: 
                      7: /****************************************************************************
                      8:  * @format.tab-size 4          (Plain Text/Source Code File Header)                    *
                      9:  * @format.use-tabs true       (see http://www.synchro.net/ptsc_hdr.html)              *
                     10:  *                                                                                                                                                     *
                     11:  * Copyright 2003 Rob Swindell - http://www.synchro.net/copyright.html         *
                     12:  *                                                                                                                                                     *
                     13:  * This program is free software; you can redistribute it and/or                       *
                     14:  * modify it under the terms of the GNU General Public License                         *
                     15:  * as published by the Free Software Foundation; either version 2                      *
                     16:  * of the License, or (at your option) any later version.                                      *
                     17:  * See the GNU General Public License for more details: gpl.txt or                     *
                     18:  * http://www.fsf.org/copyleft/gpl.html                                                                                *
                     19:  *                                                                                                                                                     *
                     20:  * Anonymous FTP access to the most recent released source is available at     *
                     21:  * ftp://vert.synchro.net, ftp://cvs.synchro.net and ftp://ftp.synchro.net     *
                     22:  *                                                                                                                                                     *
                     23:  * Anonymous CVS access to the development source and modification history     *
                     24:  * is available at cvs.synchro.net:/cvsroot/sbbs, example:                                     *
                     25:  * cvs -d :pserver:[email protected]:/cvsroot/sbbs login                       *
                     26:  *     (just hit return, no password is necessary)                                                     *
                     27:  * cvs -d :pserver:[email protected]:/cvsroot/sbbs checkout src                *
                     28:  *                                                                                                                                                     *
                     29:  * For Synchronet coding style and modification guidelines, see                                *
                     30:  * http://www.synchro.net/source.html                                                                          *
                     31:  *                                                                                                                                                     *
                     32:  * You are encouraged to submit any modifications (preferably in Unix diff     *
                     33:  * format) via e-mail to [email protected]                                                                      *
                     34:  *                                                                                                                                                     *
                     35:  * Note: If this box doesn't appear square, then you need to fix your tabs.    *
                     36:  ****************************************************************************/
                     37: 
                     38: #include <string.h>    /* strlen */
                     39: #include "crc16.h"
                     40: 
                     41: unsigned short crc16tbl[] = {
                     42: 0x0000, 0x1021, 0x2042, 0x3063, 0x4084, 0x50A5, 0x60C6, 0x70E7,
                     43: 0x8108, 0x9129, 0xA14A, 0xB16B, 0xC18C, 0xD1AD, 0xE1CE, 0xF1EF,
                     44: 0x1231, 0x0210, 0x3273, 0x2252, 0x52B5, 0x4294, 0x72F7, 0x62D6,
                     45: 0x9339, 0x8318, 0xB37B, 0xA35A, 0xD3BD, 0xC39C, 0xF3FF, 0xE3DE,
                     46: 0x2462, 0x3443, 0x0420, 0x1401, 0x64E6, 0x74C7, 0x44A4, 0x5485,
                     47: 0xA56A, 0xB54B, 0x8528, 0x9509, 0xE5EE, 0xF5CF, 0xC5AC, 0xD58D,
                     48: 0x3653, 0x2672, 0x1611, 0x0630, 0x76D7, 0x66F6, 0x5695, 0x46B4,
                     49: 0xB75B, 0xA77A, 0x9719, 0x8738, 0xF7DF, 0xE7FE, 0xD79D, 0xC7BC,
                     50: 0x48C4, 0x58E5, 0x6886, 0x78A7, 0x0840, 0x1861, 0x2802, 0x3823,
                     51: 0xC9CC, 0xD9ED, 0xE98E, 0xF9AF, 0x8948, 0x9969, 0xA90A, 0xB92B,
                     52: 0x5AF5, 0x4AD4, 0x7AB7, 0x6A96, 0x1A71, 0x0A50, 0x3A33, 0x2A12,
                     53: 0xDBFD, 0xCBDC, 0xFBBF, 0xEB9E, 0x9B79, 0x8B58, 0xBB3B, 0xAB1A,
                     54: 0x6CA6, 0x7C87, 0x4CE4, 0x5CC5, 0x2C22, 0x3C03, 0x0C60, 0x1C41,
                     55: 0xEDAE, 0xFD8F, 0xCDEC, 0xDDCD, 0xAD2A, 0xBD0B, 0x8D68, 0x9D49,
                     56: 0x7E97, 0x6EB6, 0x5ED5, 0x4EF4, 0x3E13, 0x2E32, 0x1E51, 0x0E70,
                     57: 0xFF9F, 0xEFBE, 0xDFDD, 0xCFFC, 0xBF1B, 0xAF3A, 0x9F59, 0x8F78,
                     58: 0x9188, 0x81A9, 0xB1CA, 0xA1EB, 0xD10C, 0xC12D, 0xF14E, 0xE16F,
                     59: 0x1080, 0x00A1, 0x30C2, 0x20E3, 0x5004, 0x4025, 0x7046, 0x6067,
                     60: 0x83B9, 0x9398, 0xA3FB, 0xB3DA, 0xC33D, 0xD31C, 0xE37F, 0xF35E,
                     61: 0x02B1, 0x1290, 0x22F3, 0x32D2, 0x4235, 0x5214, 0x6277, 0x7256,
                     62: 0xB5EA, 0xA5CB, 0x95A8, 0x8589, 0xF56E, 0xE54F, 0xD52C, 0xC50D,
                     63: 0x34E2, 0x24C3, 0x14A0, 0x0481, 0x7466, 0x6447, 0x5424, 0x4405,
                     64: 0xA7DB, 0xB7FA, 0x8799, 0x97B8, 0xE75F, 0xF77E, 0xC71D, 0xD73C,
                     65: 0x26D3, 0x36F2, 0x0691, 0x16B0, 0x6657, 0x7676, 0x4615, 0x5634,
                     66: 0xD94C, 0xC96D, 0xF90E, 0xE92F, 0x99C8, 0x89E9, 0xB98A, 0xA9AB,
                     67: 0x5844, 0x4865, 0x7806, 0x6827, 0x18C0, 0x08E1, 0x3882, 0x28A3,
                     68: 0xCB7D, 0xDB5C, 0xEB3F, 0xFB1E, 0x8BF9, 0x9BD8, 0xABBB, 0xBB9A,
                     69: 0x4A75, 0x5A54, 0x6A37, 0x7A16, 0x0AF1, 0x1AD0, 0x2AB3, 0x3A92,
                     70: 0xFD2E, 0xED0F, 0xDD6C, 0xCD4D, 0xBDAA, 0xAD8B, 0x9DE8, 0x8DC9,
                     71: 0x7C26, 0x6C07, 0x5C64, 0x4C45, 0x3CA2, 0x2C83, 0x1CE0, 0x0CC1,
                     72: 0xEF1F, 0xFF3E, 0xCF5D, 0xDF7C, 0xAF9B, 0xBFBA, 0x8FD9, 0x9FF8,
                     73: 0x6E17, 0x7E36, 0x4E55, 0x5E74, 0x2E93, 0x3EB2, 0x0ED1, 0x1EF0
                     74: };
                     75: 
                     76: unsigned short crc16(char* data, unsigned long len)
                     77: {
                     78:        unsigned short crc = 0;
                     79:        unsigned long l;
                     80: 
                     81:        if(len==0 && data!=NULL)
                     82:                len=strlen(data);
                     83:        for(l=0;l<len;l++)
                     84:                crc = ucrc16(data[l],crc);
                     85:  
                     86:     return(crc);
                     87: }
                     88: 

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