/*-
 * Copyright (c) 2015 Taylor R. Campbell
 * 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 AUTHOR 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 AUTHOR 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.
 */

#include <assert.h>
#include <errno.h>
#include <limits.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>

#include "err.h"
#include "emalloc.h"

#include "ereallocarr.h"

void
ereallocarr(void *ptrp, size_t nmemb, size_t elemsize)
{
	static const size_t mask = ~(size_t)0 >> (sizeof(size_t) * CHAR_BIT/2);
	void *optr, *nptr;

	assert(elemsize != 0);

	if (mask & (nmemb | elemsize)) {
		if (SIZE_MAX / elemsize < nmemb) {
			errno = ENOMEM;
			err(1, "Cannot reallocate array");
		}
	}

	(void)memcpy(&optr, ptrp, sizeof optr);
	if (nmemb == 0) {
		free(optr);
		nptr = NULL;
	} else {
		nptr = erealloc(optr, nmemb * elemsize);
	}
	(void)memcpy(ptrp, &nptr, sizeof nptr);
}