1 /*-
2 * Copyright (c) 1991 The Regents of the University of California.
3 * 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 #ifndef lint
35 static char sccsid[] = "@(#)genget.c 5.1 (Berkeley) 2/28/91";
36 #endif /* not lint */
37
38
39 #include <ctype.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 */
48 int
isprefix(s1,s2)49 isprefix(s1, s2)
50 register char *s1, *s2;
51 {
52 register int n = 0;
53 char *os1;
54 register char c1, c2;
55
56 if (*s1 == '\0')
57 return(-1);
58 os1 = s1;
59 c1 = *s1;
60 c2 = *s2;
61 while (LOWER(c1) == LOWER(c2)) {
62 if (c1 == '\0')
63 break;
64 c1 = *++s1;
65 c2 = *++s2;
66 }
67 return(*s1 ? 0 : (*s2 ? (s1 - os1) : (os1 - s1)));
68 }
69
70 static char *ambiguous; /* special return value for command routines */
71
72 char **
genget(name,table,stlen)73 genget(name, table, stlen)
74 char *name; /* name to match */
75 char **table; /* name entry in table */
76 int stlen;
77 {
78 register char **c, **found;
79 register int n;
80
81 if (name == 0)
82 return 0;
83
84 found = 0;
85 for (c = table; *c != 0; c = (char **)((char *)c + stlen)) {
86 if ((n = isprefix(name, *c)) == 0)
87 continue;
88 if (n < 0) /* exact match */
89 return(c);
90 if (found)
91 return(&ambiguous);
92 found = c;
93 }
94 return(found);
95 }
96
97 /*
98 * Function call version of Ambiguous()
99 */
100 int
Ambiguous(s)101 Ambiguous(s)
102 char *s;
103 {
104 return((char **)s == &ambiguous);
105 }
106