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compat/reallocarray.c
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/* $NetBSD: reallocarr.c,v 1.4 2015/08/20 20:08:04 joerg Exp $ */ | |||||
/*- | |||||
* Copyright (c) 2015 Joerg Sonnenberger <joerg@NetBSD.org>. | |||||
* 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. | |||||
*/ | |||||
#include <errno.h> | |||||
#include <limits.h> | |||||
#include <stddef.h> | |||||
#include <stdint.h> | |||||
#include <stdlib.h> | |||||
/* | |||||
* To be clear, this is NetBSD's more refined reallocarr(3) function | |||||
* made to look like OpenBSD's more useable reallocarray(3) interface. | |||||
*/ | |||||
#include "reallocarray.h" | |||||
#define SQRT_SIZE_MAX (((size_t)1) << (sizeof(size_t) * CHAR_BIT / 2)) | |||||
void * | |||||
reallocarray(void *ptr, size_t n, size_t size) | |||||
{ | |||||
/* | |||||
* 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 ((n | size) >= SQRT_SIZE_MAX && n > SIZE_MAX / size) { | |||||
errno = EOVERFLOW; | |||||
return NULL; | |||||
} | |||||
return realloc(ptr, n * size); | |||||
} |