gonzui

    1: /*      $OpenBSD: lsearch.c,v 1.4 2009/10/27 23:59:59 deraadt 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, const 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: }