annotate base/Selection.cpp @ 537:3cc4b7cd2aa5

* Merge from one-fftdataserver-per-fftmodel branch.  This bit of
reworking (which is not described very accurately by the title of
the branch) turns the MatrixFile object into something that either
reads or writes, but not both, and separates the FFT file cache
reader and writer implementations separately.  This allows the
FFT data server to have a single thread owning writers and one reader
per "customer" thread, and for all locking to be vastly simplified
and concentrated in the data server alone (because none of the
classes it makes use of is used in more than one thread at a time).
The result is faster and more trustworthy code.

/* -*- 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(size_t startFrame, size_t endFrame) :
    m_startFrame(startFrame),
    m_endFrame(endFrame)
{
    if (m_startFrame > m_endFrame) {
	size_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;
}

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

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

bool
Selection::contains(size_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(size_t &startFrame, size_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(size_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";
}