// ============================================================================
//  Copyright (C) 2001-2012 by Jozef Starosczyk
//  ixen@copyhandler.com
//
//  This program is free software; you can redistribute it and/or modify
//  it under the terms of the GNU Library General Public License
//  (version 2) as published by the Free Software Foundation;
//
//  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 Library General Public
//  License along with this program; if not, write to the
//  Free Software Foundation, Inc.,
//  59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
// ============================================================================
/// @file  TDataBuffer.h
/// @date  2012/03/04
/// @brief Contains class representing buffer for data.
// ============================================================================
#ifndef __TDATABUFFER_H__
#define __TDATABUFFER_H__

#include "libchcore.h"
#include <vector>
#include <list>

BEGIN_CHCORE_NAMESPACE

class TDataBufferManager;

class TSimpleDataBuffer
{
public:
	TSimpleDataBuffer();
	~TSimpleDataBuffer();

	LPVOID GetBufferPtr();
	void ReleaseBuffer();

private:
	TSimpleDataBuffer(const TSimpleDataBuffer&);
	TSimpleDataBuffer& operator=(const TSimpleDataBuffer&);

	void Initialize(TDataBufferManager& rBufferManager, LPVOID pBuffer, size_t stBufferSize);

private:
	LPVOID m_pBuffer;
	TDataBufferManager* m_pBufferManager;
	size_t m_stBufferSize;

	friend class TDataBufferManager;
};

class TDataBufferManager
{
public:
	TDataBufferManager();
	~TDataBufferManager();

	static bool CheckBufferConfig(size_t& stMaxMemory, size_t& stPageSize, size_t& stBufferSize);
	static bool CheckBufferConfig(size_t& stMaxMemory);

	// initialization
	void Initialize(size_t stMaxMemory);
	void Initialize(size_t stMaxMemory, size_t stPageSize, size_t stBufferSize);
	bool IsInitialized() const;

	// current settings
	size_t GetMaxMemorySize() const { return m_stMaxMemory; }
	size_t GetPageSize() const { return m_stPageSize; }
	size_t GetBufferSize() const { return m_stBufferSize; }

	// buffer retrieval
	bool HasFreeBuffer() const;		// checks if a buffer is available without allocating any new memory

	bool GetFreeBuffer(TSimpleDataBuffer& rSimpleBuffer);
	void ReleaseBuffer(TSimpleDataBuffer& rSimpleBuffer);

private:
	void FreeBuffers();

	bool AllocNewPage();
	bool CanAllocPage() const;	// checks if a buffer can be returned after allocating new page of memory

private:
	std::vector<LPVOID> m_vVirtualAllocBlocks;
	std::list<LPVOID> m_listUnusedBuffers;
	
	size_t m_stMaxMemory;		// maximum amount of memory to use
	size_t m_stPageSize;		// size of a single page of real memory to be allocated (allocation granularity)
	size_t m_stBufferSize;		// size of a single chunk of memory retrievable by caller
};

END_CHCORE_NAMESPACE

#endif