bootx.tproj/libclite.subproj/bsearch.c

   1 /*
   2  * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * The contents of this file constitute Original Code as defined in and
   7  * are subject to the Apple Public Source License Version 1.1 (the
   8  * "License").  You may not use this file except in compliance with the
   9  * License.  Please obtain a copy of the License at
  10  * http://www.apple.com/publicsource and read it before using this file.
  11  *
  12  * This Original Code and all software distributed under the License are
  13  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  14  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  15  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
  17  * License for the specific language governing rights and limitations
  18  * under the License.
  19  *
  20  * @APPLE_LICENSE_HEADER_END@
  21  */
  22 /*
  23  *  bsearch.c - bsearch from libc.
  24  *
  25  *  Copyright (c) 1998-2000 Apple Computer, Inc.
  26  *
  27  *  DRI: Josh de Cesare
  28  */
  29
  30 #include <libclite.h>
  31
  32 void *
  33 bsearch(const void *key, const void *base, size_t nmemb, size_t size,
  34         int (*compar)(const void *, const void *))
  35 {
  36     int l = 0;
  37     int u = nmemb - 1;
  38     int m;
  39     void *mp;
  40     int r;
  41
  42     while (l <= u) {
  43         m = (l + u) / 2;
  44         mp = (void *)(((char *)base) + (m * size));
  45         if ((r = (*compar) (key, mp)) == 0) {
  46             return mp;
  47         } else if (r < 0) {
  48             u = m - 1;
  49         } else {
  50             l = m + 1;
  51         }
  52     }
  53     return NULL;
  54 }
  55