bits/stdlib-bsearch.h

   1 /* Perform binary search - inline version.
   2    Copyright (C) 1991-2017 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 __extern_inline void *
  20 bsearch (const void *__key, const void *__base, size_t __nmemb, size_t __size,
  21          __compar_fn_t __compar)
  22 {
  23   size_t __l, __u, __idx;
  24   const void *__p;
  25   int __comparison;
  26
  27   __l = 0;
  28   __u = __nmemb;
  29   while (__l < __u)
  30     {
  31       __idx = (__l + __u) / 2;
  32       __p = (void *) (((const char *) __base) + (__idx * __size));
  33       __comparison = (*__compar) (__key, __p);
  34       if (__comparison < 0)
  35         __u = __idx;
  36       else if (__comparison > 0)
  37         __l = __idx + 1;
  38       else
  39         return (void *) __p;
  40     }
  41
  42   return NULL;
  43 }