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genget.c revision 1.8 
      1 /*	$NetBSD: genget.c,v 1.8 1998/11/06 19:20:12 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. All advertising materials mentioning features or use of this software
     16  *    must display the following acknowledgement:
     17  *	This product includes software developed by the University of
     18  *	California, Berkeley and its contributors.
     19  * 4. Neither the name of the University nor the names of its contributors
     20  *    may be used to endorse or promote products derived from this software
     21  *    without specific prior written permission.
     22  *
     23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     33  * SUCH DAMAGE.
     34  */
     35 
     36 #include <sys/cdefs.h>
     37 #ifndef lint
     38 #if 0
     39 static char sccsid[] = "@(#)genget.c	8.2 (Berkeley) 5/30/95";
     40 #else
     41 __RCSID("$NetBSD: genget.c,v 1.8 1998/11/06 19:20:12 christos Exp $");
     42 #endif
     43 #endif /* not lint */
     44 
     45 
     46 #include <ctype.h>
     47 #include "misc.h"
     48 
     49 #define	LOWER(x) (isupper((unsigned char)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  */
     56 	int
     57 isprefix(s1, s2)
     58 	register char *s1, *s2;
     59 {
     60 	char *os1;
     61 	register char c1, c2;
     62 
     63 	if (*s1 == '\0')
     64 		return(-1);
     65 	os1 = s1;
     66 	c1 = *s1;
     67 	c2 = *s2;
     68 	while (LOWER(c1) == LOWER(c2)) {
     69 		if (c1 == '\0')
     70 			break;
     71 		c1 = *++s1;
     72 		c2 = *++s2;
     73 	}
     74 	return(*s1 ? 0 : (*s2 ? (s1 - os1) : (os1 - s1)));
     75 }
     76 
     77 static char *ambiguous;		/* special return value for command routines */
     78 
     79 	char **
     80 genget(name, table, stlen)
     81 	char	*name;		/* name to match */
     82 	char	**table;	/* name entry in table */
     83 	int	stlen;
     84 {
     85 	register char **c, **found;
     86 	register int n;
     87 
     88 	if (name == 0)
     89 	    return 0;
     90 
     91 	found = 0;
     92 	for (c = table; *c != 0; c = (char **)((char *)c + stlen)) {
     93 		if ((n = isprefix(name, *c)) == 0)
     94 			continue;
     95 		if (n < 0)		/* exact match */
     96 			return(c);
     97 		if (found)
     98 			return(&ambiguous);
     99 		found = c;
    100 	}
    101 	return(found);
    102 }
    103 
    104 /*
    105  * Function call version of Ambiguous()
    106  */
    107 	int
    108 Ambiguous(s)
    109 	void *s;
    110 {
    111 	return(s == &ambiguous);
    112 }
    113