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Annotation of 43BSD/contrib/icon/functions/find.c, revision 1.1

1.1     ! root        1: #include "../h/rt.h"
        !             2: 
        !             3: /*
        !             4:  * find(s1,s2,i,j) - find string s1 in s2[i:j] and return position in
        !             5:  *  s2 of beginning of s1.
        !             6:  * Generates successive positions.
        !             7:  */
        !             8: 
        !             9: Xfind(nargs, arg4, arg3, arg2, arg1, arg0)
        !            10: int nargs;
        !            11: struct descrip arg4, arg3, arg2, arg1, arg0;
        !            12:    {
        !            13:    register int l;
        !            14:    register char *s1, *s2;
        !            15:    int i, j, t;
        !            16:    long l1, l2;
        !            17:    char sbuf1[MAXSTRING], sbuf2[MAXSTRING];
        !            18: 
        !            19:    /*
        !            20:     * s1 must be a string.  s2 defaults to &subject; i defaults to &pos
        !            21:     *  if s defaulted, 1 otherwise;  j defaults to 0.
        !            22:     */
        !            23:    if (cvstr(&arg1, sbuf1) == NULL)
        !            24:       runerr(103, &arg1);
        !            25:    if (defstr(&arg2, sbuf2, &k_subject))
        !            26:       defint(&arg3, &l1, k_pos);
        !            27:    else
        !            28:       defint(&arg3, &l1, 1);
        !            29:    defint(&arg4, &l2, 0);
        !            30: 
        !            31:    /*
        !            32:     * Convert i and j to absolute positions in s2 and order them so i <= j.
        !            33:     */
        !            34:    i = cvpos(l1, STRLEN(arg2));
        !            35:    j = cvpos(l2, STRLEN(arg2));
        !            36:    if (i > j) {
        !            37:       t = i;
        !            38:       i = j;
        !            39:       j = t;
        !            40:       }
        !            41: 
        !            42:    /*
        !            43:     * Loop through s2[i:j] trying to find s1 at each point, stopping
        !            44:     *  when the remaining portion s2[i:j] is too short to contain s1.
        !            45:     */
        !            46:    while (i <= j - STRLEN(arg1)) {
        !            47:       s1 = STRLOC(arg1);
        !            48:       s2 = STRLOC(arg2) + i - 1;
        !            49:       l = STRLEN(arg1);
        !            50:       /*
        !            51:        * Compare strings on bytewise basis; if end is reached before
        !            52:        *  inequality is found, suspend the position of the string.
        !            53:        */
        !            54:       do {
        !            55:          if (l-- <= 0) {
        !            56:             arg0.type = D_INTEGER;
        !            57:             INTVAL(arg0) = i;
        !            58:             suspend();
        !            59:             break;
        !            60:             }
        !            61:          } while (*s1++ == *s2++);
        !            62:       i++;
        !            63:       }
        !            64: 
        !            65:    fail();
        !            66:    }
        !            67: 
        !            68: Procblock(find,4)

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