glibc/misc/lsearch.c

/* Linear search functions.
   Copyright (C) 1996-2022 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, see
   <https://www.gnu.org/licenses/>.  */

#include <search.h>
#include <string.h>


void *
lsearch (const void *key, void *base, size_t *nmemb, size_t size,
	 __compar_fn_t compar)
{
  void *result;

  /* Try to find it.  */
  result = lfind (key, base, nmemb, size, compar);
  if (result == NULL)
    {
      /* Not available.  Insert at the end.  */
      result = memcpy (base + (*nmemb) * size, key, size);
      ++(*nmemb);
    }

  return result;
}


void *
lfind (const void *key, const void *base, size_t *nmemb, size_t size,
       __compar_fn_t compar)
{
  const void *result = base;
  size_t cnt = 0;

  while (cnt < *nmemb && (*compar) (key, result) != 0)
    {
      result += size;
      ++cnt;
    }

  return cnt < *nmemb ? (void *) result : NULL;
}
libc_hidden_def (lfind)