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      1 /*
      2  * Copyright 2002 Sun Microsystems, Inc.  All rights reserved.
      3  * Use is subject to license terms.
      4  */
      5 
      6 #pragma ident	"%Z%%M%	%I%	%E% SMI"
      7 
      8 /*
      9  * Copyright (c) 1991, 1993
     10  *	The Regents of the University of California.  All rights reserved.
     11  *
     12  * Redistribution and use in source and binary forms, with or without
     13  * modification, are permitted provided that the following conditions
     14  * are met:
     15  * 1. Redistributions of source code must retain the above copyright
     16  *    notice, this list of conditions and the following disclaimer.
     17  * 2. Redistributions in binary form must reproduce the above copyright
     18  *    notice, this list of conditions and the following disclaimer in the
     19  *    documentation and/or other materials provided with the distribution.
     20  * 3. All advertising materials mentioning features or use of this software
     21  *    must display the following acknowledgement:
     22  *	This product includes software developed by the University of
     23  *	California, Berkeley and its contributors.
     24  * 4. Neither the name of the University nor the names of its contributors
     25  *    may be used to endorse or promote products derived from this software
     26  *    without specific prior written permission.
     27  *
     28  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     29  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     30  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     31  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     32  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     33  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     34  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     35  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     36  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     37  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     38  * SUCH DAMAGE.
     39  */
     40 
     41 #ifndef lint
     42 static char sccsid[] = "@(#)genget.c	8.1 (Berkeley) 6/4/93";
     43 #endif /* not lint */
     44 
     45 #include <ctype.h>
     46 #include <sys/types.h>
     47 
     48 #define	LOWER(x) (isupper(x) ? tolower(x) : (x))
     49 
     50 static char *ambiguous;		/* special return value for command routines */
     51 
     52 /*
     53  * The prefix function returns 0 if *s1 is not a prefix
     54  * of *s2.  If *s1 exactly matches *s2, the negative of
     55  * the length is returned.  If *s1 is a prefix of *s2,
     56  * the length of *s1 is returned.
     57  */
     58 int
     59 isprefix(char *s1, char *s2)
     60 {
     61 	char *os1;
     62 	char c1, c2;
     63 
     64 	if (*s1 == '\0')
     65 		return (-1);
     66 	os1 = s1;
     67 	c1 = *s1;
     68 	c2 = *s2;
     69 	while (LOWER(c1) == LOWER(c2)) {
     70 		if (c1 == '\0')
     71 			break;
     72 		c1 = *++s1;
     73 		c2 = *++s2;
     74 	}
     75 	return (*s1 ? 0 : (*s2 ? (s1 - os1) : (os1 - s1)));
     76 }
     77 
     78 
     79 /*
     80  * Get an entry from the table, from what might be a prefix
     81  *
     82  * name		= name to match
     83  * table	= name entry in table
     84  */
     85 char **
     86 genget(char *name, char **table, int stlen)
     87 {
     88 	register char **c, **found;
     89 	register int n;
     90 
     91 	if (name == 0)
     92 	    return (0);
     93 
     94 	found = 0;
     95 	/*LINTED*/
     96 	for (c = table; *c != NULL; c = (char **)((char *)c + stlen)) {
     97 		if ((n = isprefix(name, *c)) == 0)
     98 			continue;
     99 		if (n < 0)		/* exact match */
    100 			return (c);
    101 		if (found)
    102 			return (&ambiguous);
    103 		found = c;
    104 	}
    105 	return (found);
    106 }
    107 
    108 /*
    109  * Function call version of Ambiguous()
    110  */
    111 boolean_t
    112 Ambiguous(void *s)
    113 {
    114 	return ((char **)s == &ambiguous);
    115 }
    116