//////////////////////////////////////////////////////////////////////
//
//                             Pixie
//
// Copyright © 1999 - 2003, Okan Arikan
//
// Contact: okan@cs.berkeley.edu
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public
// License as published by the Free Software Foundation; either
// version 2 of the License, or (at your option) any later version.
// 
// This library 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
// General Public License for more details.
// 
// You should have received a copy of the GNU 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
//
///////////////////////////////////////////////////////////////////////
///////////////////////////////////////////////////////////////////////
//
//  File				:	memory.cpp
//  Classes				:	-
//  Description			:	This file defines the misc. memory interface routines
//
////////////////////////////////////////////////////////////////////////
#include "common/os.h"
#include "memory.h"
#include "stats.h"

// The default zone size
#define	INIT_ZONE_SIZE	500000				// The intial size of the memory zone

// Some global variables
static	int					allocatedZoneMemory		=	0;
static	int					freedZoneMemory			=	0;
static	int					allocatedPages			=	0;
static	int					freedPages				=	0;
static	int					memoryPageSize			=	1000000;
static	float				lastPagingTime			=	0;
		CMemPage			*currentMemoryPage		=	NULL;


///////////////////////////////////////////////////////////////////////
// Function				:	memoryInit
// Description			:	Initialize the memory manager
// Return Value			:
// Comments				:
// Date last edited		:	1/14/2002
void			memoryInit() {
	currentMemoryPage	=	memoryNewPage(INIT_ZONE_SIZE);
}

///////////////////////////////////////////////////////////////////////
// Function				:	memoryTini
// Description			:	Destroy memory manager
// Return Value			:
// Comments				:
// Date last edited		:	1/14/2002
void			memoryTini() {
	CMemPage	*cPage;

	// We must be the first page
	assert(currentMemoryPage->prev == NULL);

	while(currentMemoryPage != NULL) {
		cPage				=	currentMemoryPage;
		currentMemoryPage	=	cPage->next;

		memoryDeletePage(cPage);
	}

	assert(allocatedZoneMemory	==	freedZoneMemory);
	assert(allocatedPages		==	freedPages);
	assert(stats.zoneMemory		==	0);
}

///////////////////////////////////////////////////////////////////////
// Function				:	memoryNewPage
// Description			:	Allocate a new memory page whose size is at least "size"
// Return Value			:
// Comments				:
// Date last edited		:	1/14/2002
CMemPage		*memoryNewPage(int size) {
	CMemPage	*newPage	=	new CMemPage;
	float		time		=	osCPUTime();

	// Are we allocating/deallocating too often ?
	if ((time - lastPagingTime) < 1) {
		memoryPageSize		+=	100000;	// Increase the zone size at 100k increments
	}
	lastPagingTime			=	time;

	size					+=	memoryPageSize;

	newPage->availableSize	=	size;
	newPage->totalSize		=	size;
	newPage->base			=	new char[size];
	newPage->memory			=	newPage->base;
	newPage->next			=	NULL;
	newPage->prev			=	NULL;

	// Stats update
	allocatedPages++;
	allocatedZoneMemory		+=	size;
	stats.zoneMemory		+=	size;

	if (stats.zoneMemory > stats.peakZoneMemory)
		stats.peakZoneMemory	=	stats.zoneMemory;

	return newPage;
}


///////////////////////////////////////////////////////////////////////
// Function				:	memoryDeletePage
// Description			:	Dealoocate memory page
// Return Value			:
// Comments				:
// Date last edited		:	1/14/2002
void		memoryDeletePage(CMemPage *cPage) {
	// Stats update
	freedPages++;
	freedZoneMemory			+=	cPage->totalSize;
	stats.zoneMemory		-=	cPage->totalSize;

	delete [] cPage->base;
	delete cPage;
}