/* ScummVM - Graphic Adventure Engine
 *
 * ScummVM is the legal property of its developers, whose names
 * are too numerous to list here. Please refer to the COPYRIGHT
 * file distributed with this source distribution.
 *
 * This program 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 3 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 */

#ifndef ELF_MEMORY_MANAGER_H
#define ELF_MEMORY_MANAGER_H

#include "common/scummsys.h"

#if defined(DYNAMIC_MODULES) && defined(USE_ELF_LOADER)

#include "common/singleton.h"
#include "common/list.h"
#include "common/mutex.h"

/**
 * A 'foolproof' way to prevent memory fragmentation. This class is used to
 * serve as a permanent allocation to prevent the process of loading and
 * unloading plugins from causing heavy fragmentation.
 **/

#define ELFMemMan		ELFMemoryManager::instance()

class ELFMemoryManager : public Common::Singleton<ELFMemoryManager> {
public:
	void trackPlugin(bool value);
	void trackAlloc(uint32 align, uint32 size);

	void allocateHeap();

	void *pluginAllocate(uint32 size);
	void *pluginAllocate(uint32 align, uint32 size);
	void pluginDeallocate(void *ptr);

private:
   friend class Common::Singleton<ELFMemoryManager>;

	ELFMemoryManager();
	~ELFMemoryManager();

	void *allocateOnHeap(uint32 align, uint32 size);
	void deallocateFromHeap(void *ptr);

	struct Allocation {
		byte *start;
		uint32 size;
		byte *end() { return start + size; }
		Allocation(byte *a, uint32 b) : start(a), size(b) {}
	};

	// heap
	void *_heap;
	uint32 _heapAlign;			// alignment of the heap
	uint32 _heapSize;			// size of the heap

	// tracking allocations
	bool _trackAllocs;		// whether we are currently tracking
	uint32 _measuredSize;
	uint32 _measuredAlign;

	// real allocations
	Common::List<Allocation> _allocList;
	uint32 _bytesAllocated;
};

#endif /* defined(DYNAMIC_MODULES) && defined(USE_ELF_LOADER) */

#endif /* ELF_MEMORY_MANAGER_H */
