appl/telnet/libtelnet/genget.c

   1 /*-
   2  * Copyright (c) 1991, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. All advertising materials mentioning features or use of this software
  14  *    must display the following acknowledgement:
  15  *      This product includes software developed by the University of
  16  *      California, Berkeley and its contributors.
  17  * 4. Neither the name of the University nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  */
  33
  34 #include <config.h>
  35 #ifdef HAVE_SYS_TYPES_H
  36 #include <sys/types.h>
  37 #endif
  38 #include <ctype.h>
  39 #include "misc-proto.h"
  40
  41 RCSID("$Id$");
  42
  43
  44 #define LOWER(x) (isupper(x) ? tolower(x) : (x))
  45 /*
  46  * The prefix function returns 0 if *s1 is not a prefix
  47  * of *s2.  If *s1 exactly matches *s2, the negative of
  48  * the length is returned.  If *s1 is a prefix of *s2,
  49  * the length of *s1 is returned.
  50  */
  51
  52 int
  53 isprefix(char *s1, char *s2)
  54 {
  55     char *os1;
  56     char c1, c2;
  57
  58     if (*s1 == '\0')
  59         return(-1);
  60     os1 = s1;
  61     c1 = *s1;
  62     c2 = *s2;
  63     while (tolower((unsigned char)c1) == tolower((unsigned char)c2)) {
  64         if (c1 == '\0')
  65             break;
  66         c1 = *++s1;
  67         c2 = *++s2;
  68     }
  69     return(*s1 ? 0 : (*s2 ? (s1 - os1) : (os1 - s1)));
  70 }
  71
  72 static char *ambiguous;         /* special return value for command routines */
  73
  74 char **
  75 genget(char *name, char **table, int stlen)
  76      /* name to match */
  77      /* name entry in table */
  78
  79 {
  80     char **c, **found;
  81     int n;
  82
  83     if (name == 0)
  84         return 0;
  85
  86     found = 0;
  87     for (c = table; *c != 0; c = (char **)((char *)c + stlen)) {
  88         if ((n = isprefix(name, *c)) == 0)
  89             continue;
  90         if (n < 0)              /* exact match */
  91             return(c);
  92         if (found)
  93             return(&ambiguous);
  94         found = c;
  95     }
  96     return(found);
  97 }
  98
  99 /*
 100  * Function call version of Ambiguous()
 101  */
 102 int
 103 Ambiguous(void *s)
 104 {
 105     return((char **)s == &ambiguous);
 106 }