misc/lsearch.c

   1 /* Linear search functions.
   2    Copyright (C) 1996-2022 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    <https://www.gnu.org/licenses/>.  */
  18
  19 #include <search.h>
  20 #include <string.h>
  21
  22
  23 void *
  24 lsearch (const void *key, void *base, size_t *nmemb, size_t size,
  25          __compar_fn_t compar)
  26 {
  27   void *result;
  28
  29   /* Try to find it.  */
  30   result = lfind (key, base, nmemb, size, compar);
  31   if (result == NULL)
  32     {
  33       /* Not available.  Insert at the end.  */
  34       result = memcpy (base + (*nmemb) * size, key, size);
  35       ++(*nmemb);
  36     }
  37
  38   return result;
  39 }
  40
  41
  42 void *
  43 lfind (const void *key, const void *base, size_t *nmemb, size_t size,
  44        __compar_fn_t compar)
  45 {
  46   const void *result = base;
  47   size_t cnt = 0;
  48
  49   while (cnt < *nmemb && (*compar) (key, result) != 0)
  50     {
  51       result += size;
  52       ++cnt;
  53     }
  54
  55   return cnt < *nmemb ? (void *) result : NULL;
  56 }
  57 libc_hidden_def (lfind)