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#ifndef lint
31#if 0
32static const char sccsid[] = "@(#)genget.c	8.2 (Berkeley) 5/30/95";
33#endif
34#endif /* not lint */
35
36
37#include <ctype.h>
38
39#include "misc-proto.h"
40
41#define	LOWER(x) (isupper(x) ? tolower(x) : (x))
42/*
43 * The prefix function returns 0 if *s1 is not a prefix
44 * of *s2.  If *s1 exactly matches *s2, the negative of
45 * the length is returned.  If *s1 is a prefix of *s2,
46 * the length of *s1 is returned.
47 */
48int
49isprefix(char *s1, const char *s2)
50{
51	char *os1;
52	char c1, c2;
53
54	if (*s1 == '\0')
55		return(-1);
56	os1 = s1;
57	c1 = *s1;
58	c2 = *s2;
59	while (LOWER(c1) == LOWER(c2)) {
60		if (c1 == '\0')
61			break;
62		c1 = *++s1;
63		c2 = *++s2;
64	}
65	return(*s1 ? 0 : (*s2 ? (s1 - os1) : (os1 - s1)));
66}
67
68static char *ambiguous;		/* special return value for command routines */
69
70char **
71genget(char *name, char **table, int stlen)
72{
73	char **c, **found;
74	int n;
75
76	if (name == 0)
77	    return 0;
78
79	found = 0;
80	for (c = table; *c != 0; c = (char **)((char *)c + stlen)) {
81		if ((n = isprefix(name, *c)) == 0)
82			continue;
83		if (n < 0)		/* exact match */
84			return(c);
85		if (found)
86			return(&ambiguous);
87		found = c;
88	}
89	return(found);
90}
91
92/*
93 * Function call version of Ambiguous()
94 */
95int
96Ambiguous(char **s)
97{
98	return(s == &ambiguous);
99}
100