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/***************************************************************************
* Copyright (C) 2005 by Joris Guisson *
* joris.guisson@gmail.com *
* *
* 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., *
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. *
***************************************************************************/
#ifndef BTMMAPFILE_H
#define BTMMAPFILE_H
#include <qstring.h>
#include <util/constants.h>
namespace bt
{
/**
* @author Joris Guisson
* @brief Memory mapped file
*
* This class allows to access memory mapped files. It's pretty similar to
* File.
* TODO: make sure large files work (not really needed for the blocklist)
*/
class MMapFile
{
public:
MMapFile();
virtual ~MMapFile();
enum Mode
{
READ,WRITE, RW
};
/**
* Open the file. If mode is write and the file doesn't exist, it will
* be created.
* @param file Filename
* @param mode Mode (READ, WRITE or RW)
* @return true upon succes
*/
bool open(const QString & file,Mode mode);
/**
* Open the file. If mode is write and the file doesn't exist, it will
* be created.
* @param file Filename
* @param mode Mode (READ, WRITE or RW)
* @param size Size of the memory mapping (the file will be enlarged to this value)
* @return true upon succes
*/
bool open(const QString & file,Mode mode,Uint64 size);
/**
* Close the file. Undoes the memory mapping.
*/
void close();
/**
* Flush the file.
*/
void flush();
/**
* Write a bunch of data.
* @param buf The data
* @param size Size of the data
* @return The number of bytes written
*/
Uint32 write(const void* buf,Uint32 size);
/**
* Read a bunch of data
* @param buf The buffer to store the data
* @param size Size of the buffer
* @return The number of bytes read
*/
Uint32 read(void* buf,Uint32 size);
enum SeekPos
{
BEGIN,
END,
CURRENT
};
/**
* Seek in the file.
* @param from Position to seek from
* @param num Number of bytes to move
* @return New position
*/
Uint64 seek(SeekPos from,Int64 num);
/// Check to see if we are at the end of the file.
bool eof() const;
/// Get the current position in the file.
Uint64 tell() const;
/// Get the error string.
QString errorString() const;
/// Get the file size
Uint64 getSize() const;
/**
* Get a pointer to the mmapped region of data.
* @param off Offset into buffer, if invalid 0 will be returned
* @return Pointer to a location in the mmapped region
*/
Uint8* getData(Uint64 off);
/// Gets the data pointer
void* getDataPointer() { return data; }
private:
void growFile(Uint64 new_size);
private:
int fd;
Uint8* data;
Uint64 size; // size of mmapping
Uint64 file_size; // size of file
Uint64 ptr;
QString filename;
Mode mode;
};
}
#endif
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