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genget.c revision 1.5 
      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. 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 /* from: static char sccsid[] = "@(#)genget.c	8.2 (Berkeley) 5/30/95"; */
     36 static char *rcsid = "$NetBSD: genget.c,v 1.5 1996/02/24 01:15:21 jtk Exp $";
     37 #endif /* not lint */
     38 
     39 
     40 #include <ctype.h>
     41 #include "misc-proto.h"
     42 
     43 int isprefix __P((char *, char *));
     44 char **genget __P((char *, char **, int));
     45 int Ambiguous __P((char *));
     46 
     47 #define	LOWER(x) (isupper(x) ? tolower(x) : (x))
     48 /*
     49  * The prefix function returns 0 if *s1 is not a prefix
     50  * of *s2.  If *s1 exactly matches *s2, the negative of
     51  * the length is returned.  If *s1 is a prefix of *s2,
     52  * the length of *s1 is returned.
     53  */
     54 	int
     55 isprefix(s1, s2)
     56 	register char *s1, *s2;
     57 {
     58 	register int n = 0;
     59 	char *os1;
     60 	register char c1, c2;
     61 
     62 	if (*s1 == '\0')
     63 		return(-1);
     64 	os1 = s1;
     65 	c1 = *s1;
     66 	c2 = *s2;
     67 	while (LOWER(c1) == LOWER(c2)) {
     68 		if (c1 == '\0')
     69 			break;
     70 		c1 = *++s1;
     71 		c2 = *++s2;
     72 	}
     73 	return(*s1 ? 0 : (*s2 ? (s1 - os1) : (os1 - s1)));
     74 }
     75 
     76 static char *ambiguous;		/* special return value for command routines */
     77 
     78 	char **
     79 genget(name, table, stlen)
     80 	char	*name;		/* name to match */
     81 	char	**table;	/* name entry in table */
     82 	int	stlen;
     83 {
     84 	register char **c, **found;
     85 	register int n;
     86 
     87 	if (name == 0)
     88 	    return 0;
     89 
     90 	found = 0;
     91 	for (c = table; *c != 0; c = (char **)((char *)c + stlen)) {
     92 		if ((n = isprefix(name, *c)) == 0)
     93 			continue;
     94 		if (n < 0)		/* exact match */
     95 			return(c);
     96 		if (found)
     97 			return(&ambiguous);
     98 		found = c;
     99 	}
    100 	return(found);
    101 }
    102 
    103 /*
    104  * Function call version of Ambiguous()
    105  */
    106 	int
    107 Ambiguous(s)
    108 	char *s;
    109 {
    110 	return((char **)s == &ambiguous);
    111 }
    112