comparison base/MatrixFileCache.h @ 87:7de62a884810

* Start factoring out the spectrogram's FFT cache into a separate set of
  classes that will permit a choice of disk or memory cache strategies

+/* -*- 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 <sys/types.h>
+#include <QString>
+
+// This class is _not_ thread safe.  Each instance must only be used
+// within a single thread.  You may however have as many instances as
+// you like referring to the same file in separate threads.
+
+class MatrixFileCache
+{
+public:
+    enum Mode { ReadOnly, ReadWrite };
+
+    MatrixFileCache(QString fileBase, Mode mode);
+    virtual ~MatrixFileCache();
+
+    size_t getWidth() const;
+    size_t getHeight() const;
+    
+    void resize(size_t width, size_t height);
+    void reset();
+
+    void setRangeOfInterest(size_t x, size_t width);
+
+    float getValueAt(size_t x, size_t y) const;
+    void getColumnAt(size_t x, float *values) const;
+//    float getColumnMaximum(size_t x) const;
+//    float getColumnMinimum(size_t x) const;
+
+    void setValueAt(size_t x, size_t y, float value);
+    void setColumnAt(size_t x, float *values);
+    
+protected:
+    int     m_fd;
+    Mode    m_mode;
+    size_t  m_width;
+    size_t  m_height;
+    size_t  m_rx;
+    size_t  m_rw;
+    float **m_range;
+    size_t  m_headerSize;
+
+    mutable off_t m_off;
+
+    bool seekTo(size_t x, size_t y) const;
+};
+
+#endif
+