comparison data/fileio/MatrixFile.h @ 148:1a42221a1522

* Reorganising code base.  This revision will not compile.

+/* -*- 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 Chris Cannam.
+    
+    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, ReadWrite };
+
+    /**
+     * 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 ReadWrite and the file does not exist, it will be
+     * created.  If mode is ReadWrite and the file does exist, the
+     * existing file will be used and the mode will be reset to
+     * ReadOnly.  Call getMode() to check whether this has occurred
+     * after construction.
+     *
+     * 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.
+     *
+     * If eagerCache is true, blocks from the file will be cached for
+     * read.  If eagerCache is false, only columns that have been set
+     * by calling setColumnAt on this MatrixFile (i.e. columns for
+     * which haveSetColumnAt returns true) will be cached.
+     */
+    MatrixFile(QString fileBase, Mode mode, size_t cellSize, bool eagerCache);
+    virtual ~MatrixFile();
+
+    Mode getMode() const { return m_mode; }
+
+    size_t getWidth() const { return m_width; }
+    size_t getHeight() const { return m_height; }
+    size_t getCellSize() const { return m_cellSize; }
+    
+    void resize(size_t width, size_t height);
+    void reset();
+
+    bool haveSetColumnAt(size_t x) const { return m_columnBitset->get(x); }
+    void getColumnAt(size_t x, void *data);
+    void setColumnAt(size_t x, const void *data);
+
+    void suspend();
+
+protected:
+    int     m_fd;
+    Mode    m_mode;
+    int     m_flags;
+    mode_t  m_fmode;
+    size_t  m_cellSize;
+    size_t  m_width;
+    size_t  m_height;
+    size_t  m_headerSize;
+    QString m_fileName;
+    size_t  m_defaultCacheWidth;
+    size_t  m_prevX;
+
+    struct Cache {
+        size_t x;
+        size_t width;
+        char *data;
+    };
+
+    Cache m_cache;
+    bool  m_eagerCache;
+
+    bool getFromCache(size_t x, size_t ystart, size_t ycount, void *data);
+    void primeCache(size_t x, bool left);
+
+    void resume();
+
+    bool seekTo(size_t x, size_t y);
+
+    static FileReadThread *m_readThread;
+    int m_requestToken;
+
+    size_t m_requestingX;
+    size_t m_requestingWidth;
+    char *m_spareData;
+
+    static std::map<QString, int> m_refcount;
+    static QMutex m_refcountMutex;
+    QMutex m_fdMutex;
+    QMutex m_cacheMutex;
+
+    typedef std::map<QString, ResizeableBitset *> ResizeableBitsetMap;
+    static ResizeableBitsetMap m_columnBitsets;
+    static QMutex m_columnBitsetWriteMutex;
+    ResizeableBitset *m_columnBitset;
+};
+
+#endif
+