misc/lsearch.c

   1 /* Linear search functions.
   2    Copyright (C) 1996-2017 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4    Contributed by Ulrich Drepper <drepper@cygnus.com>, 1996.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Lesser General Public
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library; if not, see
  18    <http://www.gnu.org/licenses/>.  */
  19
  20 #include <search.h>
  21 #include <string.h>
  22
  23
  24 void *
  25 lsearch (const void *key, void *base, size_t *nmemb, size_t size,
  26          __compar_fn_t compar)
  27 {
  28   void *result;
  29
  30   /* Try to find it.  */
  31   result = lfind (key, base, nmemb, size, compar);
  32   if (result == NULL)
  33     {
  34       /* Not available.  Insert at the end.  */
  35       result = memcpy (base + (*nmemb) * size, key, size);
  36       ++(*nmemb);
  37     }
  38
  39   return result;
  40 }
  41
  42
  43 void *
  44 lfind (const void *key, const void *base, size_t *nmemb, size_t size,
  45        __compar_fn_t compar)
  46 {
  47   const void *result = base;
  48   size_t cnt = 0;
  49
  50   while (cnt < *nmemb && (*compar) (key, result) != 0)
  51     {
  52       result += size;
  53       ++cnt;
  54     }
  55
  56   return cnt < *nmemb ? (void *) result : NULL;
  57 }
  58 libc_hidden_def (lfind)