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Viewing changes to TuxGuitar-midi/src/org/herac/tuxguitar/io/midi/MidiFileReader.java

  • Committer: Bazaar Package Importer
  • Author(s): Philippe Coval
  • Date: 2008-06-19 00:30:30 UTC
  • mto: (5.1.2 sid)
  • mto: This revision was merged to the branch mainline in revision 3.
  • Revision ID: james.westby@ubuntu.com-20080619003030-h719szrhsngou7c6
Tags: upstream-1.0
Import upstream version 1.0

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TuxGuitar-midi/src/org/herac/tuxguitar/io/midi/MidiFileReader.java
 
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package org.herac.tuxguitar.io.midi;
 
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import java.io.DataInputStream;
 
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import java.io.IOException;
 
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import java.io.InputStream;
 
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import org.herac.tuxguitar.io.midi.base.MidiEvent;
 
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import org.herac.tuxguitar.io.midi.base.MidiMessage;
 
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import org.herac.tuxguitar.io.midi.base.MidiSequence;
 
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import org.herac.tuxguitar.io.midi.base.MidiTrack;
 
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public class MidiFileReader implements MidiFileHeader{
 
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        public static boolean CANCEL_RUNNING_STATUS_ON_META_AND_SYSEX = true;
 
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        private static final int STATUS_NONE = 0;
 
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        private static final int STATUS_ONE_BYTE = 1;
 
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        private static final int STATUS_TWO_BYTES = 2;
 
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        private static final int STATUS_SYSEX = 3;
 
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        private static final int STATUS_META = 4;
 
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        public MidiSequence getSequence(InputStream stream)throws MidiFileException, IOException{
 
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                DataInputStream in = new DataInputStream(stream);
 
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                if (in.readInt() != HEADER_MAGIC){
 
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                        throw new MidiFileException("not a MIDI file: wrong header magic");
 
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                }
 
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                int headerLength = in.readInt();
 
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                if (headerLength < HEADER_LENGTH){
 
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                        throw new MidiFileException("corrupt MIDI file: wrong header length");
 
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                }
 
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                int type = in.readShort();
 
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                if (type < 0 || type > 2){
 
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                        throw new MidiFileException("corrupt MIDI file: illegal type");
 
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                }
 
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                if (type == 2){
 
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                        throw new MidiFileException("this implementation doesn't support type 2 MIDI files");
 
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                }
 
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                int trackCount = in.readShort();
 
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                if (trackCount <= 0){
 
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                        throw new MidiFileException("corrupt MIDI file: number of tracks must be positive");
 
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                }
 
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                if (type == 0 && trackCount != 1){
 
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                        throw new MidiFileException("corrupt MIDI file:  type 0 files must contain exactely one track");
 
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                }
 
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                float divisionType = -1.0F;
 
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                int resolution = -1;
 
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                int division = in.readUnsignedShort();
 
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                if ((division & 0x8000) != 0){
 
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                        int frameType = -((division >>> 8) & 0xFF);
 
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                        if(frameType == 24){
 
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                                divisionType = MidiSequence.SMPTE_24;
 
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                        }else if(frameType == 25){
 
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                                divisionType = MidiSequence.SMPTE_25;
 
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                        }else if(frameType == 29){
 
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                                divisionType = MidiSequence.SMPTE_30DROP;
 
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                        }else if(frameType == 30){
 
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                                divisionType = MidiSequence.SMPTE_30;
 
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                        }else{
 
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                                throw new MidiFileException("corrupt MIDI file: illegal frame division type");
 
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                        }
 
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                        resolution = division & 0xff;
 
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                }else{
 
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                        divisionType = MidiSequence.PPQ;
 
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                        resolution = division & 0x7fff;
 
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                }
 
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                in.skip(headerLength - HEADER_LENGTH);
 
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                MidiSequence sequence = new MidiSequence(divisionType,resolution);
 
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                for (int i = 0; i < trackCount; i++){
 
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                        MidiTrack track = new MidiTrack();
 
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                        sequence.addTrack(track);
 
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                        readTrack(in, track);
 
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                }
 
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                in.close();
 
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                return sequence;
 
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        }
 
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        private void readTrack(DataInputStream in, MidiTrack track)throws MidiFileException, IOException{
 
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                while (true){
 
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                        if (in.readInt() == TRACK_MAGIC){
 
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                                break;
 
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                        }
 
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                        int chunkLength = in.readInt();
 
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                        if (chunkLength % 2 != 0){
 
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                                chunkLength++;
 
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                        }
 
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                        in.skip(chunkLength);
 
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                }
 
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                MidiTrackReaderHelper helper = new MidiTrackReaderHelper(0,in.readInt(),-1);
 
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                while (helper.remainingBytes > 0){
 
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                        helper.ticks += readVariableLengthQuantity(in, helper);
 
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                        MidiEvent event = readEvent(in, helper);
 
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                        if(event != null){
 
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                                track.add(event);
 
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                        }
 
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                }
 
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        }
 
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        private static MidiEvent readEvent(DataInputStream in, MidiTrackReaderHelper helper)throws MidiFileException, IOException{
 
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                int statusByte = readUnsignedByte(in, helper);
 
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                int savedByte = 0;
 
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                boolean runningStatusApplies = false;
 
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                if (statusByte < 0x80){
 
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                        if (helper.runningStatusByte != -1){
 
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                                runningStatusApplies = true;
 
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                                savedByte = statusByte;
 
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                                statusByte = helper.runningStatusByte;
 
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                        }else{
 
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                                throw new MidiFileException("corrupt MIDI file: status byte missing");
 
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                        }
 
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                }
 
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                int type = getType(statusByte);
 
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                if(type == STATUS_ONE_BYTE){
 
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                        int data = 0;
 
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                        if (runningStatusApplies){
 
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                                data = savedByte;
 
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                        }else{
 
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                                data = readUnsignedByte(in, helper);
 
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                                helper.runningStatusByte = statusByte;
 
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                        }
 
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                        return new MidiEvent(MidiMessage.shortMessage((statusByte & 0xF0),(statusByte & 0x0F) , data), helper.ticks);
 
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                }else if(type == STATUS_TWO_BYTES){
 
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                        int     data1 = 0;
 
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                        if (runningStatusApplies){
 
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                                data1 = savedByte;
 
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                        }else{
 
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                                data1 = readUnsignedByte(in, helper);
 
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                                helper.runningStatusByte = statusByte;
 
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                        }
 
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                        return new MidiEvent(MidiMessage.shortMessage((statusByte & 0xF0),(statusByte & 0x0F) , data1, readUnsignedByte(in, helper)), helper.ticks);
 
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                }else if(type == STATUS_SYSEX){
 
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                        if (CANCEL_RUNNING_STATUS_ON_META_AND_SYSEX){
 
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                                helper.runningStatusByte = -1;
 
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                        }
 
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                        int dataLength = (int) readVariableLengthQuantity(in, helper);
 
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                        byte[] data = new byte[dataLength];
 
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                        for (int i = 0; i < dataLength; i++){
 
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                                data[i] = (byte) readUnsignedByte(in, helper);
 
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                        }
 
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                }else if(type == STATUS_META){
 
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                        if (CANCEL_RUNNING_STATUS_ON_META_AND_SYSEX){
 
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                                helper.runningStatusByte = -1;
 
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                        }
 
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                        int typeByte = readUnsignedByte(in, helper);
 
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                        int dataLength = (int) readVariableLengthQuantity(in, helper);
 
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                        byte[] data = new byte[dataLength];
 
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                        for (int i = 0; i < dataLength; i++){
 
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                                data[i] = (byte) readUnsignedByte(in, helper);
 
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                        }
 
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                        return new MidiEvent(MidiMessage.metaMessage(typeByte, data), helper.ticks);
 
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                }
 
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                return null;
 
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        }
 
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        private static int getType(int statusByte){
 
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                if (statusByte < 0xf0) {
 
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                        int command = statusByte & 0xf0;
 
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                        if(command == 0x80 || command == 0x90 || command == 0xa0 || command == 0xb0 || command == 0xe0){
 
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                                return STATUS_TWO_BYTES;
 
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                        }
 
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                        else if(command == 0xc0 || command == 0xd0){
 
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                                return STATUS_ONE_BYTE;
 
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                        }
 
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                        return STATUS_NONE;
 
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                }
 
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                else if (statusByte == 0xf0 || statusByte == 0xf7){
 
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                        return STATUS_SYSEX;
 
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                }
 
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                else if (statusByte == 0xff){
 
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                        return STATUS_META;
 
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                }
 
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                else{
 
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                        return STATUS_NONE;
 
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                }
 
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        }
 
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        public static long readVariableLengthQuantity(DataInputStream in, MidiTrackReaderHelper helper)throws MidiFileException, IOException{
 
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                int     count = 0;
 
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                long value = 0;
 
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                while (count < 4){
 
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                        int     data = readUnsignedByte(in, helper);
 
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                        count++;
 
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                        value <<= 7;
 
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                        value |= (data & 0x7f);
 
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                        if (data < 128){
 
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                                return value;
 
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                        }
 
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                }
 
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                throw new MidiFileException("not a MIDI file: unterminated variable-length quantity");
 
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        }
 
201
        
 
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        public static int readUnsignedByte(DataInputStream dataInputStream, MidiTrackReaderHelper helper)throws IOException{
 
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                helper.remainingBytes--;
 
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                return dataInputStream.readUnsignedByte();
 
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        }
 
206
        
 
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        private class MidiTrackReaderHelper{
 
208
                protected long ticks = 0;
 
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                protected long remainingBytes;
 
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                protected int runningStatusByte;
 
211
                
 
212
                protected MidiTrackReaderHelper(long ticks,long remainingBytes,int runningStatusByte){
 
213
                        this.ticks = ticks;
 
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                        this.remainingBytes = remainingBytes;
 
215
                        this.runningStatusByte = runningStatusByte;
 
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                }
 
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        }
 
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}
 
 
b'\\ No newline at end of file'