xref: /freebsd/crypto/heimdal/appl/telnet/libtelnet/genget.c (revision 8ddb146abcdf061be9f2c0db7e391697dafad85c)
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 }
107