comparison base/Model.h @ 0:da6937383da8

initial import

+/* -*- c-basic-offset: 4 -*-  vi:set ts=8 sts=4 sw=4: */
+
+/*
+    A waveform viewer and audio annotation editor.
+    Chris Cannam, Queen Mary University of London, 2005
+    
+    This is experimental software.  Not for distribution.
+*/
+
+#ifndef _MODEL_H_
+#define _MODEL_H_
+
+#include <vector>
+#include <QObject>
+
+typedef std::vector<float> SampleBlock;
+
+/** 
+ * Model is the base class for all data models that represent any sort
+ * of data on a time scale based on an audio frame rate.
+ */
+
+class Model : virtual public QObject
+{
+    Q_OBJECT
+
+public:
+    /**
+     * Return true if the model was constructed successfully.  Classes
+     * that refer to the model should always test this before use.
+     */
+    virtual bool isOK() const = 0;
+
+    /**
+     * Return the first audio frame spanned by the model.
+     */
+    virtual size_t getStartFrame() const = 0;
+
+    /**
+     * Return the last audio frame spanned by the model.
+     */
+    virtual size_t getEndFrame() const = 0;
+
+    /**
+     * Return the frame rate in frames per second.
+     */
+    virtual size_t getSampleRate() const = 0;
+
+    /**
+     * Return a copy of this model.
+     *
+     * If the model is not editable, this may be effectively a shallow
+     * copy.  If the model is editable, however, this operation must
+     * properly copy all of the model's editable data.
+     *
+     * In general this operation is not useful for non-editable dense
+     * models such as waveforms, because there may be no efficient
+     * copy operation implemented -- for such models it is better not
+     * to copy at all.
+     *
+     * Caller owns the returned value.
+     */
+    virtual Model *clone() const = 0;
+    
+    /**
+     * Return true if the model has finished loading or calculating
+     * all its data, for a model that is capable of calculating in a
+     * background thread.  The default implementation is appropriate
+     * for a thread that does not background any work but carries out
+     * all its calculation from the constructor or accessors.
+     *
+     * If "completion" is non-NULL, this function should return
+     * through it an estimated percentage value showing how far
+     * through the background operation it thinks it is (for progress
+     * reporting).  If it has no way to calculate progress, it may
+     * return the special value COMPLETION_UNKNOWN.
+     */
+    virtual bool isReady(int *completion = 0) const {
+	bool ok = isOK();
+	if (completion) *completion = (ok ? 100 : 0);
+	return ok;
+    }
+    static const int COMPLETION_UNKNOWN;
+
+signals:
+    /**
+     * Emitted when a model has been edited (or more data retrieved
+     * from cache, in the case of a cached model that generates slowly)
+     */
+    void modelChanged();
+
+    /**
+     * Emitted when a model has been edited (or more data retrieved
+     * from cache, in the case of a cached model that generates slowly)
+     */
+    void modelChanged(size_t startFrame, size_t endFrame);
+
+    /**
+     * Emitted when some internal processing has advanced a stage, but
+     * the model has not changed externally.  Views should respond by
+     * updating any progress meters or other monitoring, but not
+     * refreshing the actual view.
+     */
+    void completionChanged();
+
+protected:
+    Model() { }
+
+    // Not provided.
+    Model(const Model &);
+    Model &operator=(const Model &); 
+};
+
+#endif