/* $NetBSD: reallocarr.c,v 1.5 2015/08/20 22:27:49 kamil Exp $ */

/*-
* Copyright (c) 2015 Joerg Sonnenberger <[email protected]>.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
*    notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
*    notice, this list of conditions and the following disclaimer in
*    the documentation and/or other materials provided with the
*    distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
* COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/

#if HAVE_NBTOOL_CONFIG_H
#include "nbtool_config.h"
#endif

#include <sys/cdefs.h>
__RCSID("$NetBSD: reallocarr.c,v 1.5 2015/08/20 22:27:49 kamil Exp $");

#include "namespace.h"
#include <errno.h>
/* Old POSIX has SIZE_MAX in limits.h */
#include <limits.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>

#ifdef _LIBC
#ifdef __weak_alias
__weak_alias(reallocarr, _reallocarr)
#endif
#endif

#define SQRT_SIZE_MAX (((size_t)1) << (sizeof(size_t) * CHAR_BIT / 2))

#if !HAVE_REALLOCARR
int
reallocarr(void *ptr, size_t number, size_t size)
{
       int saved_errno, result;
       void *optr;
       void *nptr;

       saved_errno = errno;
       memcpy(&optr, ptr, sizeof(ptr));
       if (number == 0 || size == 0) {
               free(optr);
               nptr = NULL;
               memcpy(ptr, &nptr, sizeof(ptr));
               errno = saved_errno;
               return 0;
       }

       /*
        * Try to avoid division here.
        *
        * It isn't possible to overflow during multiplication if neither
        * operand uses any of the most significant half of the bits.
        */
       if (__predict_false((number|size) >= SQRT_SIZE_MAX &&
                           number > SIZE_MAX / size)) {
               errno = saved_errno;
               return EOVERFLOW;
       }

       nptr = realloc(optr, number * size);
       if (__predict_false(nptr == NULL)) {
               result = errno;
       } else {
               result = 0;
               memcpy(ptr, &nptr, sizeof(ptr));
       }
       errno = saved_errno;
       return result;
}
#endif