1 /* $OpenBSD: lsearch.c,v 1.5 2014/07/18 04:16:09 matthew Exp $ */ 2 3 /* 4 * Copyright (c) 1989, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from software contributed to Berkeley by 8 * Roger L. Snyder. 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. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 */ 34 35 #include <sys/types.h> 36 #include <string.h> 37 #include <search.h> 38 39 typedef int (*cmp_fn_t)(const void *, const void *); 40 static void *linear_base(const void *, const void *, size_t *, size_t, 41 cmp_fn_t, int); 42 43 void * 44 lsearch(const void *key, void *base, size_t *nelp, size_t width, 45 cmp_fn_t compar) 46 { 47 48 return(linear_base(key, base, nelp, width, compar, 1)); 49 } 50 51 void * 52 lfind(const void *key, const void *base, size_t *nelp, size_t width, 53 cmp_fn_t compar) 54 { 55 return(linear_base(key, base, nelp, width, compar, 0)); 56 } 57 58 static void * 59 linear_base(const void *key, const void *base, size_t *nelp, size_t width, 60 cmp_fn_t compar, int add_flag) 61 { 62 const char *element, *end; 63 64 end = (const char *)base + *nelp * width; 65 for (element = base; element < end; element += width) 66 if (!compar(key, element)) /* key found */ 67 return((void *)element); 68 69 if (!add_flag) /* key not found */ 70 return(NULL); 71 72 /* 73 * The UNIX System User's Manual, 1986 edition claims that 74 * a NULL pointer is returned by lsearch with errno set 75 * appropriately, if there is not enough room in the table 76 * to add a new item. This can't be done as none of these 77 * routines have any method of determining the size of the 78 * table. This comment isn't in the 1986-87 System V 79 * manual. 80 */ 81 ++*nelp; 82 memcpy((void *)end, key, width); 83 return((void *)end); 84 } 85
