usr/src/cmd/cmd-inet/usr.bin/telnet/genget.c

   1 /*
   2  * Copyright 2002 Sun Microsystems, Inc.  All rights reserved.
   3  * Use is subject to license terms.
   4  */
   5
   6 #pragma ident   "%Z%%M% %I%     %E% SMI"
   7
   8 /*
   9  * Copyright (c) 1991, 1993
  10  *      The Regents of the University of California.  All rights reserved.
  11  *
  12  * Redistribution and use in source and binary forms, with or without
  13  * modification, are permitted provided that the following conditions
  14  * are met:
  15  * 1. Redistributions of source code must retain the above copyright
  16  *    notice, this list of conditions and the following disclaimer.
  17  * 2. Redistributions in binary form must reproduce the above copyright
  18  *    notice, this list of conditions and the following disclaimer in the
  19  *    documentation and/or other materials provided with the distribution.
  20  * 3. All advertising materials mentioning features or use of this software
  21  *    must display the following acknowledgement:
  22  *      This product includes software developed by the University of
  23  *      California, Berkeley and its contributors.
  24  * 4. Neither the name of the University nor the names of its contributors
  25  *    may be used to endorse or promote products derived from this software
  26  *    without specific prior written permission.
  27  *
  28  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  29  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  30  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  31  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  32  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  33  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  34  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  35  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  36  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  37  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  38  * SUCH DAMAGE.
  39  */
  40
  41 static char sccsid[] = "@(#)genget.c    8.1 (Berkeley) 6/4/93";
  42
  43 #include <ctype.h>
  44 #include <sys/types.h>
  45
  46 #define LOWER(x) (isupper(x) ? tolower(x) : (x))
  47
  48 static char *ambiguous;         /* special return value for command routines */
  49
  50 /*
  51  * The prefix function returns 0 if *s1 is not a prefix
  52  * of *s2.  If *s1 exactly matches *s2, the negative of
  53  * the length is returned.  If *s1 is a prefix of *s2,
  54  * the length of *s1 is returned.
  55  */
  56 int
  57 isprefix(char *s1, char *s2)
  58 {
  59         char *os1;
  60         char c1, c2;
  61
  62         if (*s1 == '\0')
  63                 return (-1);
  64         os1 = s1;
  65         c1 = *s1;
  66         c2 = *s2;
  67         while (LOWER(c1) == LOWER(c2)) {
  68                 if (c1 == '\0')
  69                         break;
  70                 c1 = *++s1;
  71                 c2 = *++s2;
  72         }
  73         return (*s1 ? 0 : (*s2 ? (s1 - os1) : (os1 - s1)));
  74 }
  75
  76
  77 /*
  78  * Get an entry from the table, from what might be a prefix
  79  *
  80  * name         = name to match
  81  * table        = name entry in table
  82  */
  83 char **
  84 genget(char *name, char **table, int stlen)
  85 {
  86         register char **c, **found;
  87         register int n;
  88
  89         if (name == 0)
  90             return (0);
  91
  92         found = 0;
  93         /*LINTED*/
  94         for (c = table; *c != NULL; c = (char **)((char *)c + stlen)) {
  95                 if ((n = isprefix(name, *c)) == 0)
  96                         continue;
  97                 if (n < 0)              /* exact match */
  98                         return (c);
  99                 if (found)
 100                         return (&ambiguous);
 101                 found = c;
 102         }
 103         return (found);
 104 }
 105
 106 /*
 107  * Function call version of Ambiguous()
 108  */
 109 boolean_t
 110 Ambiguous(void *s)
 111 {
 112         return ((char **)s == &ambiguous);
 113 }