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Annotation of sbbs/sbbs2/smb/crc16.c, revision 1.1

1.1     ! root        1: /* CRC16.C */
        !             2: 
        !             3: /* Developed 1990-1997 by Rob Swindell; PO Box 501, Yorba Linda, CA 92885 */
        !             4: 
        !             5: /* 16-bit CRC routines */
        !             6: 
        !             7: #include "smblib.h"
        !             8: 
        !             9: /****************************************************************************/
        !            10: /* Updates 16-bit "rcrc" with character 'ch'                                */
        !            11: /****************************************************************************/
        !            12: void ucrc16(uchar ch, ushort *rcrc) {
        !            13:     ushort i, cy;
        !            14:     uchar nch=ch;
        !            15:  
        !            16: for (i=0; i<8; i++) {
        !            17:     cy=*rcrc & 0x8000;
        !            18:     *rcrc<<=1;
        !            19:     if (nch & 0x80) *rcrc |= 1;
        !            20:     nch<<=1;
        !            21:     if (cy) *rcrc ^= 0x1021; }
        !            22: }
        !            23: 
        !            24: /****************************************************************************/
        !            25: /* Returns 16-crc of string (not counting terminating NULL)                 */
        !            26: /****************************************************************************/
        !            27: ushort SMBCALL crc16(char *str)
        !            28: {
        !            29:     int     i=0;
        !            30:     ushort  crc=0;
        !            31: 
        !            32: ucrc16(0,&crc);
        !            33: while(str[i])
        !            34:     ucrc16(str[i++],&crc);
        !            35: ucrc16(0,&crc);
        !            36: ucrc16(0,&crc);
        !            37: return(crc);
        !            38: }
        !            39: 

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