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			91 lines
		
	
	
		
			2.4 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			91 lines
		
	
	
		
			2.4 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
/*	$OpenBSD: recallocarray.c,v 1.1 2017/03/06 18:44:21 otto Exp $	*/
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/*
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 * Copyright (c) 2008, 2017 Otto Moerbeek <otto@drijf.net>
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 *
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 * Permission to use, copy, modify, and distribute this software for any
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 * purpose with or without fee is hereby granted, provided that the above
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 * copyright notice and this permission notice appear in all copies.
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 *
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 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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 */
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/* OPENBSD ORIGINAL: lib/libc/stdlib/recallocarray.c */
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#include "includes.h"
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#ifndef HAVE_RECALLOCARRAY
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#include <errno.h>
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#include <stdlib.h>
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#ifdef HAVE_STDINT_H
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#include <stdint.h>
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#endif
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#include <string.h>
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#include <unistd.h>
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/*
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 * This is sqrt(SIZE_MAX+1), as s1*s2 <= SIZE_MAX
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 * if both s1 < MUL_NO_OVERFLOW and s2 < MUL_NO_OVERFLOW
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 */
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#define MUL_NO_OVERFLOW ((size_t)1 << (sizeof(size_t) * 4))
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void *
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recallocarray(void *ptr, size_t oldnmemb, size_t newnmemb, size_t size)
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{
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	size_t oldsize, newsize;
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	void *newptr;
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	if (ptr == NULL)
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		return calloc(newnmemb, size);
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	if ((newnmemb >= MUL_NO_OVERFLOW || size >= MUL_NO_OVERFLOW) &&
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	    newnmemb > 0 && SIZE_MAX / newnmemb < size) {
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		errno = ENOMEM;
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		return NULL;
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	}
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	newsize = newnmemb * size;
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	if ((oldnmemb >= MUL_NO_OVERFLOW || size >= MUL_NO_OVERFLOW) &&
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	    oldnmemb > 0 && SIZE_MAX / oldnmemb < size) {
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		errno = EINVAL;
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		return NULL;
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	}
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	oldsize = oldnmemb * size;
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	/*
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	 * Don't bother too much if we're shrinking just a bit,
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	 * we do not shrink for series of small steps, oh well.
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	 */
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	if (newsize <= oldsize) {
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		size_t d = oldsize - newsize;
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		if (d < oldsize / 2 && d < (size_t)getpagesize()) {
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			memset((char *)ptr + newsize, 0, d);
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			return ptr;
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		}
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	}
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	newptr = malloc(newsize);
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	if (newptr == NULL)
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		return NULL;
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	if (newsize > oldsize) {
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		memcpy(newptr, ptr, oldsize);
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		memset((char *)newptr + oldsize, 0, newsize - oldsize);
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	} else
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		memcpy(newptr, ptr, newsize);
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	explicit_bzero(ptr, oldsize);
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	free(ptr);
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	return newptr;
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}
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/* DEF_WEAK(recallocarray); */
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#endif /* HAVE_RECALLOCARRAY */
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