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subr_optstr.c revision 1.4.40.1 
      1 /*	$NetBSD: subr_optstr.c,v 1.4.40.1 2008/05/18 12:35:09 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  *
     19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     29  * POSSIBILITY OF SUCH DAMAGE.
     30  */
     31 
     32 #include <sys/cdefs.h>
     33 __KERNEL_RCSID(0, "$NetBSD: subr_optstr.c,v 1.4.40.1 2008/05/18 12:35:09 yamt Exp $");
     34 
     35 #include <sys/param.h>
     36 #include <sys/optstr.h>
     37 
     38 /* --------------------------------------------------------------------- */
     39 
     40 /*
     41  * Given an options string of the form 'a=b c=d ... y=z' and a key,
     42  * looks for the given key's value in the string and returns it in buf
     43  * with a maximum of bufsize bytes.  If the key is found, returns true;
     44  * otherwise FALSE.
     45  */
     46 bool
     47 optstr_get(const char *optstr, const char *key, char *buf, size_t bufsize)
     48 {
     49 	bool found;
     50 
     51 	found = false;
     52 
     53 	/* Skip any initial spaces until we find a word. */
     54 	while (*optstr == ' ' && *optstr != '\0')
     55 		optstr++;
     56 
     57 	/* Search for the given key within the option string. */
     58 	while (!found && *optstr != '\0') {
     59 		const char *keyp;
     60 
     61 		/* Check if the next word matches the key. */
     62 		keyp = key;
     63 		while (*optstr == *keyp) {
     64 			optstr++;
     65 			keyp++;
     66 		}
     67 
     68 		if (*optstr == '=' && *keyp == '\0')
     69 			found = true;
     70 		else {
     71 			/* Key not found; skip until next space. */
     72 			while (*optstr != ' ' && *optstr != '\0')
     73 				optstr++;
     74 
     75 			/* And now skip until next word. */
     76 			while (*optstr == ' ' && *optstr != '\0')
     77 				optstr++;
     78 		}
     79 	}
     80 
     81 	/* If the key was found; copy its value to the target buffer. */
     82 	if (found) {
     83 		const char *lastbuf;
     84 
     85 		lastbuf = buf + (bufsize - 1);
     86 
     87 		optstr++; /* Skip '='. */
     88 		while (buf != lastbuf && *optstr != ' ' && *optstr != '\0')
     89 			*buf++ = *optstr++;
     90 		*buf = '\0';
     91 	}
     92 
     93 	return found;
     94 }
     95