friend class DB;

public:

const Status allocatePage(int& pageNo); // allocate a new page

const Status disposePage(const int pageNo); // release space for a page

const Status readPage(const int pageNo,

Page* pagePtr) const; // read page from file

const Status writePage(const int pageNo,

const Page* pagePtr); // write page to file

const Status getFirstPage(int& pageNo) const; // returns pageNo of first page

bool operator == (const File & other) const

{

return fileName == other.fileName;

}

bool operator < (const File & other) const

{

return fileName < other.fileName;

}

void printName() const

{

cout << "File: " << fileName << endl;

}

private:

File(const string & fname); // initialize

~File(); // deallocate file object

static const Status create(const string & fileName);

static const Status destroy(const string & fileName);

const Status open();

const Status close();

// Check if the page is on the free list

const Status onFreeList(const int pageNo, bool& onFL) const;

const Status intread(const int pageNo,

Page* pagePtr) const; // internal file read

const Status intwrite(const int pageNo,

const Page* pagePtr); // internal file write

#ifdef DEBUGFREE

void listFree(); // list free pages

#endif

string fileName; // The name of the file

int openCnt; // # times file has been opened

int unixFile; // unix file stream for file

public:

DB(); // initialize open file table

~DB(); // clean up any remaining open files

const Status createFile(const string & fileName) const; // create a new file

const Status destroyFile(const string & fileName) const; // destroy a file,

// release all space

const Status openFile(const string & fileName, File* & file); // open a file

const Status closeFile(File* file); // close a file

private:

typedef map<string, File* > OpenFileMap;

OpenFileMap openFiles; // list of open files