filehdr.h

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/////////////////////////////////////////////////////////////
//FileName		: filehdr.h
//
//Creator		: Fang WenBin(0410706)
//CreateTime	: 2006-12-26
//
//File Desc: 
//		the header of filehdr.cc, which implement two class:
//		1. s_Bitmap -- bimap used for allocate disk space
//		2. FileHeader -- the inode!
/////////////////////////////////////////////////////////////

#include "copyright.h"

#ifndef FILEHDR_H
#define FILEHDR_H

#include "disk.h"
#include "bitmap.h"

#define NumDirect 	((SectorSize - 2 * sizeof(int)) / sizeof(int))
#define MaxFileSize 	(NumDirect * SectorSize)

#define s_NUM_OF_INDEX 6			//the total number of inode index slot

///
///use for inode's s_fileMode field
///
#define s_DIR_TYPE	0x00000001		//directory type	
#define s_FILE_TYPE 0x00000002		//file type
#define s_DIR_ONE	0x00000010		//level 1 dir
#define s_DIR_TWO	0x00000020		//level 2 dir
#define s_DIR_THREE 0x00000040		//level 3 dir
#define s_DIR_FOUR	0x00000080		//level 4 dir

///
///use for allocate disk space
///
class s_Bitmap
{
	public:
		s_Bitmap(int nitems);
		~s_Bitmap();
			
		void Mark(int which);
		void Clear(int which);
		bool Test(int which);
		int Find();
		int NumClear();
		void Print();
		void FetchFrom(int startSector, int totalSector);
		void WriteBack(int startSector, int totalSector);

		int numBits;		
		int numBytes;		//total bytes in this bitmap to manage
		char *map;			//the bits buffer
};

///
/// inode!
///
class FileHeader {
  public:
    bool Allocate(BitMap *bitMap, int fileSize);
    void Deallocate(BitMap *bitMap);  	

    void FetchFrom(int sectorNumber, int pos); 
    void WriteBack(int sectorNumber, int pos); 	

    int ByteToSector(int offset);	

    int FileLength();		

    void Print();		

	void s_Allocate(s_Bitmap *zMap, char *data, int size);
	void s_DeAllocate(s_Bitmap *zMap);

	int s_fileMode;							//file attribute
	int s_dataSectors[s_NUM_OF_INDEX];		//data slot numbers
    int numBytes;							//file size
};

#endif // FILEHDR_H