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/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*- vi:set ts=8 sts=4 sw=4: */
/*
Sonic Visualiser
An audio file viewer and annotation editor.
Centre for Digital Music, Queen Mary, University of London.
This file copyright 2006-2009 Chris Cannam and QMUL.
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. See the file
COPYING included with this distribution for more information.
*/
#ifndef _MATRIX_FILE_CACHE_H_
#define _MATRIX_FILE_CACHE_H_
#include "base/ResizeableBitset.h"
#include "FileReadThread.h"
#include <sys/types.h>
#include <QString>
#include <QMutex>
#include <map>
class MatrixFile : public QObject
{
Q_OBJECT
public:
enum Mode { ReadOnly, WriteOnly };
/**
* Construct a MatrixFile object reading from and/or writing to
* the matrix file with the given base name in the application's
* temporary directory.
*
* If mode is ReadOnly, the file must exist and be readable.
*
* If mode is WriteOnly, the file must not exist.
*
* cellSize specifies the size in bytes of the object type stored
* in the matrix. For example, use cellSize = sizeof(float) for a
* matrix of floats. The MatrixFile object doesn't care about the
* objects themselves, it just deals with raw data of a given size.
*
* width and height specify the dimensions of the file. These
* cannot be changed after construction.
*
* MatrixFiles are reference counted by name. When the last
* MatrixFile with a given name is destroyed, the file is removed.
* These are temporary files; the normal usage is to have one
* MatrixFile of WriteOnly type creating the file and then
* persisting until all readers are complete.
*
* MatrixFile has no built-in cache and is not thread-safe. Use a
* separate MatrixFile in each thread.
*/
MatrixFile(QString fileBase, Mode mode, int cellSize,
int width, int height);
virtual ~MatrixFile();
Mode getMode() const { return m_mode; }
int getWidth() const { return m_width; }
int getHeight() const { return m_height; }
int getCellSize() const { return m_cellSize; }
/**
* If this is set true on a write-mode MatrixFile, then the file
* will close() itself when all columns have been written.
*/
void setAutoClose(bool a) { m_autoClose = a; }
void close(); // does not decrement ref count; that happens in dtor
bool haveSetColumnAt(int x) const;
void getColumnAt(int x, void *data); // may throw FileReadFailed
void setColumnAt(int x, const void *data);
protected:
int m_fd;
Mode m_mode;
int m_flags;
mode_t m_fmode;
int m_cellSize;
int m_width;
int m_height;
int m_headerSize;
QString m_fileName;
ResizeableBitset *m_setColumns; // only in writer
bool m_autoClose;
// In reader: if this is >= 0, we can read that column directly
// without seeking (and we know that the column exists)
mutable int m_readyToReadColumn;
static std::map<QString, int> m_refcount;
static QMutex m_createMutex;
void initialise();
bool seekTo(int col) const;
};
#endif
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