compat_reallocarray.c

   1 #include "config.h"
   2
   3 #if HAVE_REALLOCARRAY
   4
   5 int dummy;
   6
   7 #else
   8
   9 /*      $Id: compat_reallocarray.c,v 1.4 2014/12/11 09:05:01 schwarze Exp $     */
  10 /*      $OpenBSD: reallocarray.c,v 1.2 2014/12/08 03:45:00 bcook Exp $  */
  11 /*
  12  * Copyright (c) 2008 Otto Moerbeek <otto@drijf.net>
  13  *
  14  * Permission to use, copy, modify, and distribute this software for any
  15  * purpose with or without fee is hereby granted, provided that the above
  16  * copyright notice and this permission notice appear in all copies.
  17  *
  18  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  19  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  20  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  21  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  22  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  23  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  24  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  25  */
  26
  27 #include <sys/types.h>
  28 #include <errno.h>
  29 #include <stdint.h>
  30 #include <stdlib.h>
  31
  32 /*
  33  * This is sqrt(SIZE_MAX+1), as s1*s2 <= SIZE_MAX
  34  * if both s1 < MUL_NO_OVERFLOW and s2 < MUL_NO_OVERFLOW
  35  */
  36 #define MUL_NO_OVERFLOW ((size_t)1 << (sizeof(size_t) * 4))
  37
  38 void *
  39 reallocarray(void *optr, size_t nmemb, size_t size)
  40 {
  41         if ((nmemb >= MUL_NO_OVERFLOW || size >= MUL_NO_OVERFLOW) &&
  42             nmemb > 0 && SIZE_MAX / nmemb < size) {
  43                 errno = ENOMEM;
  44                 return NULL;
  45         }
  46         return realloc(optr, size * nmemb);
  47 }
  48
  49 #endif /*!HAVE_REALLOCARRAY*/