/*
  File: high_water_alloc.c

  Copyright (C) 2001-2002 Silicon Graphics, Inc.  All Rights Reserved.

  This program is free software; you can redistribute it and/or
  modify it under the terms of the GNU Lesser General Public
  License as published by the Free Software Foundation; either
  version 2 of the License, or (at your option) any later version.

  This program is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General Public
  License along with this library; if not, write to the Free Software
  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/

#include <stdio.h>
#include <stdlib.h>
#include "misc.h"

int high_water_alloc(void **buf, size_t *bufsize, size_t newsize)
{
#define CHUNK_SIZE	256
	/*
	 * Goal here is to avoid unnecessary memory allocations by
	 * using static buffers which only grow when necessary.
	 * Size is increased in fixed size chunks (CHUNK_SIZE).
	 */
	if (*bufsize < newsize) {
		void *newbuf;

		newsize = (newsize + CHUNK_SIZE-1) & ~(CHUNK_SIZE-1);
		newbuf = realloc(*buf, newsize);
		if (!newbuf)
			return 1;
		
		*buf = newbuf;
		*bufsize = newsize;
	}
	return 0;
}
