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. Neither the name of the University nor the names of its contributors
14 *    may be used to endorse or promote products derived from this software
15 *    without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 */
29
30#include <sys/cdefs.h>
31
32__FBSDID("$FreeBSD$");
33
34#ifndef lint
35#if 0
36static const char sccsid[] = "@(#)genget.c	8.2 (Berkeley) 5/30/95";
37#endif
38#endif /* not lint */
39
40
41#include <ctype.h>
42
43#include "misc-proto.h"
44
45#define	LOWER(x) (isupper(x) ? tolower(x) : (x))
46/*
47 * The prefix function returns 0 if *s1 is not a prefix
48 * of *s2.  If *s1 exactly matches *s2, the negative of
49 * the length is returned.  If *s1 is a prefix of *s2,
50 * the length of *s1 is returned.
51 */
52int
53isprefix(char *s1, const 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 (LOWER(c1) == LOWER(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
72static char *ambiguous;		/* special return value for command routines */
73
74char **
75genget(char *name, char **table, int stlen)
76{
77	char **c, **found;
78	int n;
79
80	if (name == 0)
81	    return 0;
82
83	found = 0;
84	for (c = table; *c != 0; c = (char **)((char *)c + stlen)) {
85		if ((n = isprefix(name, *c)) == 0)
86			continue;
87		if (n < 0)		/* exact match */
88			return(c);
89		if (found)
90			return(&ambiguous);
91		found = c;
92	}
93	return(found);
94}
95
96/*
97 * Function call version of Ambiguous()
98 */
99int
100Ambiguous(char **s)
101{
102	return(s == &ambiguous);
103}
104