view base/Selection.cpp @ 1752:6d09d68165a4 by-id

Further review of ById: make IDs only available when adding a model to the ById store, not by querying the item directly. This means any id encountered in the wild must have been added to the store at some point (even if later released), which simplifies reasoning about lifecycles

/* -*- 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.
*/

#include "Selection.h"
#include <QTextStream>

Selection::Selection() :
    m_startFrame(0),
    m_endFrame(0)
{
}

Selection::Selection(sv_frame_t startFrame, sv_frame_t endFrame) :
    m_startFrame(startFrame),
    m_endFrame(endFrame)
{
    if (m_startFrame > m_endFrame) {
        sv_frame_t tmp = m_endFrame;
        m_endFrame = m_startFrame;
        m_startFrame = tmp;
    }
}

Selection::Selection(const Selection &s) :
    m_startFrame(s.m_startFrame),
    m_endFrame(s.m_endFrame)
{
}

Selection &
Selection::operator=(const Selection &s)
{
    if (this != &s) {
        m_startFrame = s.m_startFrame;
        m_endFrame = s.m_endFrame;
    } 
    return *this;
}

Selection::~Selection()
{
}

bool
Selection::isEmpty() const
{
    return m_startFrame == m_endFrame;
}

sv_frame_t
Selection::getStartFrame() const
{
    return m_startFrame;
}

sv_frame_t
Selection::getEndFrame() const
{
    return m_endFrame;
}

bool
Selection::contains(sv_frame_t frame) const
{
    return (frame >= m_startFrame) && (frame < m_endFrame);
}

bool
Selection::operator<(const Selection &s) const
{
    if (isEmpty()) {
        if (s.isEmpty()) return false;
        else return true;
    } else {
        if (s.isEmpty()) return false;
        else return (m_startFrame < s.m_startFrame);
    }
}

bool
Selection::operator==(const Selection &s) const
{
    if (isEmpty()) return s.isEmpty();

    return (m_startFrame == s.m_startFrame &&
            m_endFrame == s.m_endFrame);
}


MultiSelection::MultiSelection()
{
}

MultiSelection::~MultiSelection()
{
}

const MultiSelection::SelectionList &
MultiSelection::getSelections() const
{
    return m_selections;
}

void
MultiSelection::setSelection(const Selection &selection)
{
    clearSelections();
    addSelection(selection);
}

void
MultiSelection::addSelection(const Selection &selection)
{
    m_selections.insert(selection);

    // Cope with a sitation where the new selection overlaps one or
    // more existing ones.  This is a terribly inefficient way to do
    // this, but that probably isn't significant in real life.

    // It's essential for the correct operation of
    // getContainingSelection that the selections do not overlap, so
    // this is not just a frill.

    for (SelectionList::iterator i = m_selections.begin();
         i != m_selections.end(); ) {
        
        SelectionList::iterator j = i;
        if (++j == m_selections.end()) break;

        if (i->getEndFrame() >= j->getStartFrame()) {
            Selection merged(i->getStartFrame(),
                             std::max(i->getEndFrame(), j->getEndFrame()));
            m_selections.erase(i);
            m_selections.erase(j);
            m_selections.insert(merged);
            i = m_selections.begin();
        } else {
            ++i;
        }
    }
}

void
MultiSelection::removeSelection(const Selection &selection)
{
    //!!! Likewise this needs to cope correctly with the situation
    //where selection is not one of the original selection set but
    //simply overlaps one of them (cutting down the original selection
    //appropriately)

    if (m_selections.find(selection) != m_selections.end()) {
        m_selections.erase(selection);
    }
}

void
MultiSelection::clearSelections()
{
    if (!m_selections.empty()) {
        m_selections.clear();
    }
}

void
MultiSelection::getExtents(sv_frame_t &startFrame, sv_frame_t &endFrame) const
{
    startFrame = 0;
    endFrame = 0;
    
    for (SelectionList::const_iterator i = m_selections.begin();
         i != m_selections.end(); ++i) {

        if (i == m_selections.begin() || i->getStartFrame() < startFrame) {
            startFrame = i->getStartFrame();
        }

        if (i == m_selections.begin() || i->getEndFrame() > endFrame) {
            endFrame = i->getEndFrame();
        }
    }
}

Selection
MultiSelection::getContainingSelection(sv_frame_t frame, bool defaultToFollowing) const
{
    // This scales very badly with the number of selections, but it's
    // more efficient for very small numbers of selections than a more
    // scalable method, and I think that may be what we need

    for (SelectionList::const_iterator i = m_selections.begin();
         i != m_selections.end(); ++i) {

        if (i->contains(frame)) return *i;

        if (i->getStartFrame() > frame) {
            if (defaultToFollowing) return *i;
            else return Selection();
        }
    }

    return Selection();
}

void
MultiSelection::toXml(QTextStream &stream, QString indent,
                      QString extraAttributes) const
{
    stream << indent << QString("<selections %1>\n").arg(extraAttributes);
    for (SelectionList::iterator i = m_selections.begin();
         i != m_selections.end(); ++i) {
        stream << indent
               << QString("  <selection start=\"%1\" end=\"%2\"/>\n")
            .arg(i->getStartFrame()).arg(i->getEndFrame());
    }
    stream << indent << "</selections>\n";
}