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subr_optstr.c revision 1.1.16.4 
      1 /*	$NetBSD: subr_optstr.c,v 1.1.16.4 2007/02/26 09:11:15 yamt Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2006 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Julio M. Merino Vidal.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  * 3. All advertising materials mentioning features or use of this software
     19  *    must display the following acknowledgement:
     20  *	This product includes software developed by the NetBSD
     21  *	Foundation, Inc. and its contributors.
     22  * 4. Neither the name of The NetBSD Foundation nor the names of its
     23  *    contributors may be used to endorse or promote products derived
     24  *    from this software without specific prior written permission.
     25  *
     26  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     27  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     28  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     29  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     30  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     31  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     32  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     33  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     34  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     35  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     36  * POSSIBILITY OF SUCH DAMAGE.
     37  */
     38 
     39 #include <sys/cdefs.h>
     40 __KERNEL_RCSID(0, "$NetBSD: subr_optstr.c,v 1.1.16.4 2007/02/26 09:11:15 yamt Exp $");
     41 
     42 #include <sys/param.h>
     43 #include <sys/optstr.h>
     44 
     45 /* --------------------------------------------------------------------- */
     46 
     47 /*
     48  * Given an options string of the form 'a=b c=d ... y=z' and a key,
     49  * looks for the given key's value in the string and returns it in buf
     50  * with a maximum of bufsize bytes.  If the key is found, returns true;
     51  * otherwise FALSE.
     52  */
     53 bool
     54 optstr_get(const char *optstr, const char *key, char *buf, size_t bufsize)
     55 {
     56 	bool found;
     57 
     58 	found = false;
     59 
     60 	/* Skip any initial spaces until we find a word. */
     61 	while (*optstr == ' ' && *optstr != '\0')
     62 		optstr++;
     63 
     64 	/* Search for the given key within the option string. */
     65 	while (!found && *optstr != '\0') {
     66 		const char *keyp;
     67 
     68 		/* Check if the next word matches the key. */
     69 		keyp = key;
     70 		while (*optstr == *keyp) {
     71 			optstr++;
     72 			keyp++;
     73 		}
     74 
     75 		if (*optstr == '=' && *keyp == '\0')
     76 			found = true;
     77 		else {
     78 			/* Key not found; skip until next space. */
     79 			while (*optstr != ' ' && *optstr != '\0')
     80 				optstr++;
     81 
     82 			/* And now skip until next word. */
     83 			while (*optstr == ' ' && *optstr != '\0')
     84 				optstr++;
     85 		}
     86 	}
     87 
     88 	/* If the key was found; copy its value to the target buffer. */
     89 	if (found) {
     90 		const char *lastbuf;
     91 
     92 		lastbuf = buf + (bufsize - 1);
     93 
     94 		optstr++; /* Skip '='. */
     95 		while (buf != lastbuf && *optstr != ' ' && *optstr != '\0')
     96 			*buf++ = *optstr++;
     97 		*buf = '\0';
     98 	}
     99 
    100 	return found;
    101 }
    102