buffermgr.h

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/*
 *  Openmysee
 *
 *  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 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 General Public License for more details.
 *
 *  You should have received a copy of the GNU 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
 *
 */
#ifndef __BUFFERMGR_H_
#define __BUFFERMGR_H_

#include "BaseResource.h"

namespace NPLayer1 {

class BufferMgr {
public:
	// 构造函数
	BufferMgr();
	// 析构函数
	~BufferMgr();

	// 是否已经初始化
	bool HasInited() {return (blockArray != NULL);};
	// 取得缓冲文件的大小
	UINT GetBufferFileSize() { return bufferFileSize; };
	// 取得缓冲文件名
	string GetBufferFileName() { return bufferFileName; };

	// 初始化缓冲文件，只能调用一次
	P2P_RETURN_TYPE Init(string fullPath, bool& bufFileModified, UINT randNum, UINT bufferSize = BUFFER_SPACE);

	// 取得一个未使用的块, 并将其置为已使用
	UINT GetEmptyIndex(UINT randNum);
	// 将一个块置为未使用
	void EraseIndex(UINT index);

	// 获取剩余空间大小
	UINT GetEmptySpace();

	// 取得一个块的数据
	P2P_RETURN_TYPE GetIndexData(UINT index, UINT offset, LPVOID data, UINT size);
	// 填充一个块
	P2P_RETURN_TYPE PutIndexData(UINT index, LPVOID data, UINT size);

public:
	static BOOL ExCreateFile(HANDLE&, LPCTSTR lpFileName, DWORD dwDesiredAccess,
		DWORD dwShareMode, LPSECURITY_ATTRIBUTES lpSecurityAttributes,
		DWORD dwCreationDisposition, DWORD dwFlagsAndAttributes, 
		HANDLE hTemplateFile);
	static BOOL ExCreateFile(HANDLE&, LPCTSTR lpFileName, DWORD dwCreationDisposition);
	static UINT ExReadFile(HANDLE, LPVOID buf, UINT toBeRead);
	static UINT ExWriteFile(HANDLE, LPCVOID buf, UINT toBeWrite);
	static BOOL ExSetFilePointer(HANDLE, UINT offset);
	static BOOL ExSetFileSize(HANDLE, UINT size);
	static BOOL GetSelfModulePath(LPTSTR buf, DWORD nSize);

private:
	enum {
		// 默认缓冲文件大小24MB
		BUFFER_SPACE = 1048576*24, 
	};
	// 缓冲文件的句柄
	HANDLE hBufferFile;
	// 缓冲文件名
	string bufferFileName;
	// 缓冲文件大小
	UINT bufferFileSize;
	
	// 记录缓冲文件的使用情况，按分块
	bool* blockArray;
	// 缓冲文件的分块个数
	UINT blockNum;
};
}

#endif