annotate base/Selection.h @ 1376:d9511f9e04d7 dev/refactor-piper-related

Introduce some POD structs for describing an external server application and the desired libraries to load from it, and disambiguating between empty list request and invalid list request. This allows for overriding PiperVampPluginFactory behaviour for using a PluginScan to populate the list request.

/* -*- 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 _SELECTION_H_
#define _SELECTION_H_

#include <cstddef>
#include <set>

#include "XmlExportable.h"
#include "BaseTypes.h"

/**
 * A selection object simply represents a range in time, via start and
 * end frame.
 *
 * The end frame is the index of the frame just *after* the end of the
 * selection. For example a selection of length 10 frames starting at
 * time 0 will have start frame 0 and end frame 10. This will be
 * contiguous with (rather than overlapping with) a selection that
 * starts at frame 10.
 *
 * Any selection with equal start and end frames is empty,
 * representing "no selection". All empty selections are equal under
 * the comparison operators. The default constructor makes an empty
 * selection with start and end frames equal to zero.
 */
class Selection
{
public:
    Selection();
    Selection(sv_frame_t startFrame, sv_frame_t endFrame);
    Selection(const Selection &);
    Selection &operator=(const Selection &);
    virtual ~Selection();

    bool isEmpty() const;
    sv_frame_t getStartFrame() const;
    sv_frame_t getEndFrame() const;
    bool contains(sv_frame_t frame) const;

    bool operator<(const Selection &) const;
    bool operator==(const Selection &) const;
    
protected:
    sv_frame_t m_startFrame;
    sv_frame_t m_endFrame;
};

class MultiSelection : public XmlExportable
{
public:
    MultiSelection();
    virtual ~MultiSelection();

    typedef std::set<Selection> SelectionList;

    const SelectionList &getSelections() const;
    void setSelection(const Selection &selection);
    void addSelection(const Selection &selection);
    void removeSelection(const Selection &selection);
    void clearSelections();

    void getExtents(sv_frame_t &startFrame, sv_frame_t &endFrame) const;

    /**
     * Return the selection that contains a given frame.
     * If defaultToFollowing is true, and if the frame is not in a
     * selected area, return the next selection after the given frame.
     * Return the empty selection if no appropriate selection is found.
     */
    Selection getContainingSelection(sv_frame_t frame, bool defaultToFollowing) const;

    virtual void toXml(QTextStream &stream, QString indent = "",
                       QString extraAttributes = "") const;

protected:
    SelectionList m_selections;
};
    

#endif