#ifndef lint
static const char	RCSid[] = "$Id: bmalloc.c,v 2.3 2003/02/22 02:07:21 greg Exp $";
#endif
/*
 * Bmalloc provides basic memory allocation without overhead (no free lists).
 * Use only to take the load off of malloc for all those
 * piddling little requests that you never expect to free.
 * Bmalloc defers to malloc for big requests.
 * Bfree should hand memory to bmalloc, but it usually fails here.
 *
 *  External symbols declared in standard.h
 */

/* ====================================================================
 * The Radiance Software License, Version 1.0
 *
 * Copyright (c) 1990 - 2002 The Regents of the University of California,
 * through Lawrence Berkeley National Laboratory.   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.
 *
 * 3. The end-user documentation included with the redistribution,
 *           if any, must include the following acknowledgment:
 *             "This product includes Radiance software
 *                 (http://radsite.lbl.gov/)
 *                 developed by the Lawrence Berkeley National Laboratory
 *               (http://www.lbl.gov/)."
 *       Alternately, this acknowledgment may appear in the software itself,
 *       if and wherever such third-party acknowledgments normally appear.
 *
 * 4. The names "Radiance," "Lawrence Berkeley National Laboratory"
 *       and "The Regents of the University of California" must
 *       not be used to endorse or promote products derived from this
 *       software without prior written permission. For written
 *       permission, please contact radiance@radsite.lbl.gov.
 *
 * 5. Products derived from this software may not be called "Radiance",
 *       nor may "Radiance" appear in their name, without prior written
 *       permission of Lawrence Berkeley National Laboratory.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED 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 Lawrence Berkeley National Laboratory OR
 * ITS 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.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of Lawrence Berkeley National Laboratory.   For more
 * information on Lawrence Berkeley National Laboratory, please see
 * <http://www.lbl.gov/>.
 */

#include <stdlib.h>

#ifndef  MBLKSIZ
#define  MBLKSIZ	16376		/* size of memory allocation block */
#endif
#define  WASTEFRAC	12		/* don't waste more than a fraction */
#ifndef  ALIGNT
#define  ALIGNT		double		/* type for alignment */
#endif
#define  BYTES_WORD	sizeof(ALIGNT)

static char  *bposition = NULL;
static unsigned int  nremain = 0;


char *
bmalloc(n)		/* allocate a block of n bytes */
register unsigned int  n;
{
	if (n > nremain && (n > MBLKSIZ || nremain > MBLKSIZ/WASTEFRAC))
		return(malloc(n));			/* too big */

	n = (n+(BYTES_WORD-1))&~(BYTES_WORD-1);		/* word align */

	if (n > nremain && (bposition = (char *)malloc(nremain = MBLKSIZ)) == NULL) {
		nremain = 0;
		return(NULL);
	}
	bposition += n;
	nremain -= n;
	return(bposition - n);
}


void
bfree(p, n)			/* free random memory */
register char	*p;
register unsigned int	n;
{
	register unsigned int	bsiz;
					/* check alignment */
	bsiz = BYTES_WORD - ((unsigned int)p&(BYTES_WORD-1));
	if (bsiz < BYTES_WORD) {
		p += bsiz;
		n -= bsiz;
	}
	if (p + n == bposition) {	/* just allocated? */
		bposition = p;
		nremain += n;
		return;
	}
	if (n > nremain) {		/* better than what we've got? */
		bposition = p;
		nremain = n;
		return;
	}
				/* just throw it away, then */
}