MIDISongPlayer.cxx

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/*
 * Copyright (c) 2001-2004 MUSIC TECHNOLOGY GROUP (MTG)
 * UNIVERSITAT POMPEU FABRA
 *
 * 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.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 *
 * MIDIFileReader C++ classes
 * This code is part of the CLAM library, but also usable stand-alone.
 * Maarten de Boer <mdeboer@iua.upf.es>
 *
 */
#include <vector>
#include "MIDISongPlayer.hxx"
#include "MIDITrack.hxx"
#include "MIDISong.hxx"


namespace MIDI
{

        class TrackPlayer
        /* a helper class for SongPlayerImpl to iterate through each track */
        {
        friend class SongPlayerImpl;
        private:
                Track* mTrack;
                std::list<Event*>::const_iterator mIterator;
        public:
                TrackPlayer(Track* track);

        };

        TrackPlayer::TrackPlayer(Track* track)
        {
                mTrack = track;
                mIterator =  mTrack->Begin();
        }

        class SongPlayerImpl
        {
        /* hidden implementation of class SongPlayer */
        friend class SongPlayer;
        private:
                Song* mSong;
                std::vector<TrackPlayer*> mTrackPlayerList;
                SongPlayerImpl(Song* song)
                {
                        Init(song);
                }
                
                void Init(Song* song)
                {
                        mTrackPlayerList.clear();
                        mSong = song;
                        if (mSong)
                        {
                                for (int i=0;i<mSong->Tracks();i++)
                                {
                                        mTrackPlayerList.push_back(
                                                new TrackPlayer(mSong->GetTrack(i)));
                                }
                        }
                }

                bool GetEvent(Event& event,int& trackId)
                {
                        Ticks smallest = 0;
                        int smallestId = -1;

                        for (unsigned int i=0;i<mTrackPlayerList.size();i++)
                        /* look for the track with the next event */
                        {
                                if (mTrackPlayerList[i]->mIterator != 
                                        mTrackPlayerList[i]->mTrack->End())
                                {
                                        Event* ev = *mTrackPlayerList[i]->mIterator;
                                        if (smallestId==-1 || ev->GetTicks()<smallest)
                                        {
                                                smallest = ev->GetTicks();
                                                smallestId = i;
                                        }
                                }
                        }
                        if (smallestId != -1)
                        {
                                /* return it and increment the iterator of that track */
                                event = *(*(mTrackPlayerList[smallestId]->mIterator));
                                trackId = smallestId;
                                mTrackPlayerList[smallestId]->mIterator++;
                                return true;
                        }
                        return false;
                }

        };
        
        SongPlayer::SongPlayer(Song* song)
        {
                mImpl = new SongPlayerImpl(song);
        }

        void SongPlayer::Init(Song* song)
        {
                mImpl->Init(song);
        }
        
        SongPlayer::~SongPlayer()
        {
                delete mImpl;
        }

        bool SongPlayer::GetEvent(Event& event,int& trackId)
        {
                return mImpl->GetEvent(event,trackId);
        }
        
}