4.3BSD - /usr/src/new/icon/functions/match.c

   1: #include "../h/rt.h"
   2: 
   3: /*
   4:  * match(s1,s2,i,j) - test if s1 is prefix of s2[i:j].
   5:  */
   6: Xmatch(nargs, arg4, arg3, arg2, arg1, arg0)
   7: int nargs;
   8: struct descrip arg4, arg3, arg2, arg1, arg0;
   9:    {
  10:    register int i;
  11:    register char *s1, *s2;
  12:    int j, t;
  13:    long l1, l2;
  14:    char sbuf1[MAXSTRING], sbuf2[MAXSTRING];
  15: 
  16:    /*
  17:     * s1 must be a string.  s2 defaults to &subject;  i defaults to &pos
  18:     *  if s defaulted, 1 otherwise; j defaults to 0.
  19:     */
  20:    if (cvstr(&arg1, sbuf1) == NULL)
  21:       runerr(103, &arg1);
  22:    if (defstr(&arg2, sbuf2, &k_subject))
  23:       defint(&arg3, &l1, k_pos);
  24:    else
  25:       defint(&arg3, &l1, 1);
  26:    defint(&arg4, &l2, 0);
  27: 
  28:    /*
  29:     * Convert i and j to absolute positions and then make i the smaller
  30:     *  of the two positions and make j the length of the substring.
  31:     */
  32:    i = cvpos(l1, STRLEN(arg2));
  33:    j = cvpos(l2, STRLEN(arg2));
  34:    if (i > j) {
  35:       t = i;
  36:       i = j;
  37:       j = t - j;
  38:       }
  39:    else
  40:       j = j - i;
  41: 
  42:    /*
  43:     * Can't match unless s1 is as long as s2[i:j].
  44:     */
  45:    if (j < STRLEN(arg1))
  46:       fail();
  47: 
  48:    /*
  49:     * Compare s1 with s2[i:j] for *s1 characters; fail if an inequality
  50:     *  if found.
  51:     */
  52:    s1 = STRLOC(arg1);
  53:    s2 = STRLOC(arg2) + i - 1;
  54:    for (j = STRLEN(arg1); j > 0; j--)
  55:       if (*s1++ != *s2++)
  56:          fail();
  57: 
  58:    /*
  59:     * Return position of end of matched string in s2.
  60:     */
  61:    arg0.type = D_INTEGER;
  62:    INTVAL(arg0) = i + STRLEN(arg1);
  63:    }
  64: 
  65: Procblock(match,4)

Defined functions