/*-
 * Copyright (c)1997-2005 by Hartmut Brandt
 * 	All rights reserved.
 *
 * Author: Harti Brandt <harti@freebsd.org>
 * 
 * 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 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 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.
 *
 * $Begemot: libbegemot/xrealloc.c,v 1.4 2005/06/01 07:51:22 brandt_h Exp $
 */
# include <stdio.h>
# include <stdlib.h>
# include "begemot.h"

/*
 * Do a sensible thing:
 *	xrealloc(NULL, 0)	-> malloc(0) or malloc(1)
 *	xrealloc(NULL, s)	-> malloc(s)
 *	xrealloc(p,    0)	-> free(p), malloc(0) or malloc(1)
 *	xrealloc(p,    s)	-> realloc(p, s)
 * The Solaris man page says: 'when realloc returns NULL, the block pointed
 * to by ptr is left intact.' It's not clear whether this means, the block
 * is freed, but you can still read it or it is not touched is not clear.
 * That's why we have to check the boundary cases BEFORE calling realloc.
 */
void *
xrealloc(void *p, size_t s)
{
	void *ptr;

	if(p == NULL) {
		if((ptr=malloc(s)) == NULL && (s!=0 || (ptr=malloc(1)) == NULL))
			panic("out of memory: xrealloc(%lx, %lu)",
				(unsigned long)p, (unsigned long)s);
	} else if(s == 0) {
		free(p);
		if((ptr=malloc(s)) == NULL && (ptr=malloc(1)) == NULL)
			panic("out of memory: xrealloc(%lx, %lu)",
				(unsigned long)p, (unsigned long)s);
	} else {
		if((ptr = realloc(p, s)) == NULL)
			panic("out of memory: xrealloc(%lx, %lu)",
				(unsigned long)p, (unsigned long)s);
	}

	return ptr;
}