1 /* $NetBSD: genget.c,v 1.14 2018/12/14 23:42:39 christos Exp $ */
2
3 /*-
4 * Copyright (c) 1991, 1993
5 * The Regents of the University of California. All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the University nor the names of its contributors
16 * may be used to endorse or promote products derived from this software
17 * without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32 #include <sys/cdefs.h>
33 #ifndef lint
34 #if 0
35 static char sccsid[] = "@(#)genget.c 8.2 (Berkeley) 5/30/95";
36 #else
37 __RCSID("$NetBSD: genget.c,v 1.14 2018/12/14 23:42:39 christos Exp $");
38 #endif
39 #endif /* not lint */
40
41
42 #include <ctype.h>
43 #include "misc.h"
44
45 #define LOWER(x) (isupper((unsigned char)x) ? tolower((unsigned char)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 */
52 int
isprefix(const char * s1,const char * s2)53 isprefix(const char *s1, const char *s2)
54 {
55 const 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
72 static char *ambiguous; /* special return value for command routines */
73
74 char **
genget(const char * name,char ** table,int stlen)75 genget(const char *name, /* name to match */
76 char **table, /* name entry in table */
77 int stlen)
78 {
79 register char **c, **found;
80 register int n;
81
82 if (name == 0)
83 return 0;
84
85 found = 0;
86 for (c = table; *c != 0; c = (char **)((char *)c + stlen)) {
87 if ((n = isprefix(name, *c)) == 0)
88 continue;
89 if (n < 0) /* exact match */
90 return(c);
91 if (found)
92 return(&ambiguous);
93 found = c;
94 }
95 return(found);
96 }
97
98 /*
99 * Function call version of Ambiguous()
100 */
101 int
Ambiguous(void * s)102 Ambiguous(void *s)
103 {
104 return(s == &ambiguous);
105 }
106