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__FBSDID("$FreeBSD: src/contrib/telnet/libtelnet/genget.c,v 1.7 2001/11/30 21:06:34 markm Exp $");
37
38#ifndef lint
39#if 0
40static const char sccsid[] = "@(#)genget.c	8.2 (Berkeley) 5/30/95";
41#endif
42#endif /* not lint */
43
44
45#include <ctype.h>
46
47#include "misc-proto.h"
48
49#define	LOWER(x) (isupper(x) ? tolower(x) : (x))
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 */
56int
57isprefix(char *s1, const 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
76static char *ambiguous;		/* special return value for command routines */
77
78char **
79genget(char *name, char **table, int stlen)
80{
81	char **c, **found;
82	int n;
83
84	if (name == 0)
85	    return 0;
86
87	found = 0;
88	for (c = table; *c != 0; c = (char **)((char *)c + stlen)) {
89		if ((n = isprefix(name, *c)) == 0)
90			continue;
91		if (n < 0)		/* exact match */
92			return(c);
93		if (found)
94			return(&ambiguous);
95		found = c;
96	}
97	return(found);
98}
99
100/*
101 * Function call version of Ambiguous()
102 */
103int
104Ambiguous(char **s)
105{
106	return(s == &ambiguous);
107}
108