lib/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 <sys/cdefs.h>
  35
  36 #ifdef __FBSDID
  37 __FBSDID("$FreeBSD: src/crypto/telnet/libtelnet/genget.c,v 1.2.8.2 2002/04/13 10:59:07 markm Exp $");
  38 #endif
  39
  40 #ifndef lint
  41 #if 0
  42 static const char sccsid[] = "@(#)genget.c      8.2 (Berkeley) 5/30/95";
  43 #endif
  44 #endif /* not lint */
  45
  46
  47 #include <ctype.h>
  48
  49 #include "misc-proto.h"
  50
  51 #define LOWER(x) (isupper(x) ? tolower(x) : (x))
  52 /*
  53  * The prefix function returns 0 if *s1 is not a prefix
  54  * of *s2.  If *s1 exactly matches *s2, the negative of
  55  * the length is returned.  If *s1 is a prefix of *s2,
  56  * the length of *s1 is returned.
  57  */
  58 int
  59 isprefix(char *s1, const char *s2)
  60 {
  61         char *os1;
  62         char c1, c2;
  63
  64         if (*s1 == '\0')
  65                 return(-1);
  66         os1 = s1;
  67         c1 = *s1;
  68         c2 = *s2;
  69         while (LOWER(c1) == LOWER(c2)) {
  70                 if (c1 == '\0')
  71                         break;
  72                 c1 = *++s1;
  73                 c2 = *++s2;
  74         }
  75         return(*s1 ? 0 : (*s2 ? (s1 - os1) : (os1 - s1)));
  76 }
  77
  78 static char *ambiguous;         /* special return value for command routines */
  79
  80 char **
  81 genget(char *name, char **table, int stlen)
  82 {
  83         char **c, **found;
  84         int n;
  85
  86         if (name == 0)
  87             return 0;
  88
  89         found = 0;
  90         for (c = table; *c != 0; c = (char **)((char *)c + stlen)) {
  91                 if ((n = isprefix(name, *c)) == 0)
  92                         continue;
  93                 if (n < 0)              /* exact match */
  94                         return(c);
  95                 if (found)
  96                         return(&ambiguous);
  97                 found = c;
  98         }
  99         return(found);
 100 }
 101
 102 /*
 103  * Function call version of Ambiguous()
 104  */
 105 int
 106 Ambiguous(char **s)
 107 {
 108         return(s == &ambiguous);
 109 }