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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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package com.sun.media.sound;

import java.io.BufferedInputStream;
import java.io.DataInputStream;
import java.io.EOFException;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;

import javax.sound.midi.InvalidMidiDataException;
import javax.sound.midi.MetaMessage;
import javax.sound.midi.MidiEvent;
import javax.sound.midi.MidiFileFormat;
import javax.sound.midi.MidiMessage;
import javax.sound.midi.Sequence;
import javax.sound.midi.SysexMessage;
import javax.sound.midi.Track;
import javax.sound.midi.spi.MidiFileReader;

MIDI file reader.
Author:Kara Kytle, Jan Borgersen, Florian Bomers
/** * MIDI file reader. * * @author Kara Kytle * @author Jan Borgersen * @author Florian Bomers */
public final class StandardMidiFileReader extends MidiFileReader { private static final int MThd_MAGIC = 0x4d546864; // 'MThd' private static final int bisBufferSize = 1024; // buffer size in buffered input streams public MidiFileFormat getMidiFileFormat(InputStream stream) throws InvalidMidiDataException, IOException { return getMidiFileFormatFromStream(stream, MidiFileFormat.UNKNOWN_LENGTH, null); } // $$fb 2002-04-17: part of fix for 4635286: MidiSystem.getMidiFileFormat() // returns format having invalid length private MidiFileFormat getMidiFileFormatFromStream(InputStream stream, int fileLength, SMFParser smfParser) throws InvalidMidiDataException, IOException{ int maxReadLength = 16; int duration = MidiFileFormat.UNKNOWN_LENGTH; DataInputStream dis; if (stream instanceof DataInputStream) { dis = (DataInputStream) stream; } else { dis = new DataInputStream(stream); } if (smfParser == null) { dis.mark(maxReadLength); } else { smfParser.stream = dis; } int type; int numtracks; float divisionType; int resolution; try { int magic = dis.readInt(); if( !(magic == MThd_MAGIC) ) { // not MIDI throw new InvalidMidiDataException("not a valid MIDI file"); } // read header length int bytesRemaining = dis.readInt() - 6; type = dis.readShort(); numtracks = dis.readShort(); int timing = dis.readShort(); // decipher the timing code if (timing > 0) { // tempo based timing. value is ticks per beat. divisionType = Sequence.PPQ; resolution = timing; } else { // SMPTE based timing. first decipher the frame code. int frameCode = -1 * (timing >> 8); switch(frameCode) { case 24: divisionType = Sequence.SMPTE_24; break; case 25: divisionType = Sequence.SMPTE_25; break; case 29: divisionType = Sequence.SMPTE_30DROP; break; case 30: divisionType = Sequence.SMPTE_30; break; default: throw new InvalidMidiDataException("Unknown frame code: " + frameCode); } // now determine the timing resolution in ticks per frame. resolution = timing & 0xFF; } if (smfParser != null) { // remainder of this chunk dis.skip(bytesRemaining); smfParser.tracks = numtracks; } } finally { // if only reading the file format, reset the stream if (smfParser == null) { dis.reset(); } } MidiFileFormat format = new MidiFileFormat(type, divisionType, resolution, fileLength, duration); return format; } public MidiFileFormat getMidiFileFormat(URL url) throws InvalidMidiDataException, IOException { InputStream urlStream = url.openStream(); // throws IOException BufferedInputStream bis = new BufferedInputStream( urlStream, bisBufferSize ); MidiFileFormat fileFormat = null; try { fileFormat = getMidiFileFormat( bis ); // throws InvalidMidiDataException } finally { bis.close(); } return fileFormat; } public MidiFileFormat getMidiFileFormat(File file) throws InvalidMidiDataException, IOException { FileInputStream fis = new FileInputStream(file); // throws IOException BufferedInputStream bis = new BufferedInputStream(fis, bisBufferSize); // $$fb 2002-04-17: part of fix for 4635286: MidiSystem.getMidiFileFormat() returns format having invalid length long length = file.length(); if (length > Integer.MAX_VALUE) { length = MidiFileFormat.UNKNOWN_LENGTH; } MidiFileFormat fileFormat = null; try { fileFormat = getMidiFileFormatFromStream(bis, (int) length, null); } finally { bis.close(); } return fileFormat; } public Sequence getSequence(InputStream stream) throws InvalidMidiDataException, IOException { SMFParser smfParser = new SMFParser(); MidiFileFormat format = getMidiFileFormatFromStream(stream, MidiFileFormat.UNKNOWN_LENGTH, smfParser); // must be MIDI Type 0 or Type 1 if ((format.getType() != 0) && (format.getType() != 1)) { throw new InvalidMidiDataException("Invalid or unsupported file type: " + format.getType()); } // construct the sequence object Sequence sequence = new Sequence(format.getDivisionType(), format.getResolution()); // for each track, go to the beginning and read the track events for (int i = 0; i < smfParser.tracks; i++) { if (smfParser.nextTrack()) { smfParser.readTrack(sequence.createTrack()); } else { break; } } return sequence; } public Sequence getSequence(URL url) throws InvalidMidiDataException, IOException { InputStream is = url.openStream(); // throws IOException is = new BufferedInputStream(is, bisBufferSize); Sequence seq = null; try { seq = getSequence(is); } finally { is.close(); } return seq; } public Sequence getSequence(File file) throws InvalidMidiDataException, IOException { InputStream is = new FileInputStream(file); // throws IOException is = new BufferedInputStream(is, bisBufferSize); Sequence seq = null; try { seq = getSequence(is); } finally { is.close(); } return seq; } } //=============================================================================================================
State variables during parsing of a MIDI file.
/** * State variables during parsing of a MIDI file. */
final class SMFParser { private static final int MTrk_MAGIC = 0x4d54726b; // 'MTrk' // set to true to not allow corrupt MIDI files tombe loaded private static final boolean STRICT_PARSER = false; private static final boolean DEBUG = false; int tracks; // number of tracks DataInputStream stream; // the stream to read from private int trackLength = 0; // remaining length in track private byte[] trackData = null; private int pos = 0; SMFParser() { } private int readUnsigned() throws IOException { return trackData[pos++] & 0xFF; } private void read(byte[] data) throws IOException { System.arraycopy(trackData, pos, data, 0, data.length); pos += data.length; } private long readVarInt() throws IOException { long value = 0; // the variable-lengh int value int currentByte = 0; do { currentByte = trackData[pos++] & 0xFF; value = (value << 7) + (currentByte & 0x7F); } while ((currentByte & 0x80) != 0); return value; } private int readIntFromStream() throws IOException { try { return stream.readInt(); } catch (EOFException eof) { throw new EOFException("invalid MIDI file"); } } boolean nextTrack() throws IOException, InvalidMidiDataException { int magic; trackLength = 0; do { // $$fb 2003-08-20: fix for 4910986: MIDI file parser breaks up on http connection if (stream.skipBytes(trackLength) != trackLength) { if (!STRICT_PARSER) { return false; } throw new EOFException("invalid MIDI file"); } magic = readIntFromStream(); trackLength = readIntFromStream(); } while (magic != MTrk_MAGIC); if (!STRICT_PARSER) { if (trackLength < 0) { return false; } } // now read track in a byte array try { trackData = new byte[trackLength]; } catch (final OutOfMemoryError oom) { throw new IOException("Track length too big", oom); } try { // $$fb 2003-08-20: fix for 4910986: MIDI file parser breaks up on http connection stream.readFully(trackData); } catch (EOFException eof) { if (!STRICT_PARSER) { return false; } throw new EOFException("invalid MIDI file"); } pos = 0; return true; } private boolean trackFinished() { return pos >= trackLength; } void readTrack(Track track) throws IOException, InvalidMidiDataException { try { // reset current tick to 0 long tick = 0; // reset current status byte to 0 (invalid value). // this should cause us to throw an InvalidMidiDataException if we don't // get a valid status byte from the beginning of the track. int status = 0; boolean endOfTrackFound = false; while (!trackFinished() && !endOfTrackFound) { MidiMessage message; int data1 = -1; // initialize to invalid value int data2 = 0; // each event has a tick delay and then the event data. // first read the delay (a variable-length int) and update our tick value tick += readVarInt(); // check for new status int byteValue = readUnsigned(); if (byteValue >= 0x80) { status = byteValue; } else { data1 = byteValue; } switch (status & 0xF0) { case 0x80: case 0x90: case 0xA0: case 0xB0: case 0xE0: // two data bytes if (data1 == -1) { data1 = readUnsigned(); } data2 = readUnsigned(); message = new FastShortMessage(status | (data1 << 8) | (data2 << 16)); break; case 0xC0: case 0xD0: // one data byte if (data1 == -1) { data1 = readUnsigned(); } message = new FastShortMessage(status | (data1 << 8)); break; case 0xF0: // sys-ex or meta switch(status) { case 0xF0: case 0xF7: // sys ex int sysexLength = (int) readVarInt(); byte[] sysexData = new byte[sysexLength]; read(sysexData); SysexMessage sysexMessage = new SysexMessage(); sysexMessage.setMessage(status, sysexData, sysexLength); message = sysexMessage; break; case 0xFF: // meta int metaType = readUnsigned(); int metaLength = (int) readVarInt(); final byte[] metaData; try { metaData = new byte[metaLength]; } catch (final OutOfMemoryError oom) { throw new IOException("Meta length too big", oom); } read(metaData); MetaMessage metaMessage = new MetaMessage(); metaMessage.setMessage(metaType, metaData, metaLength); message = metaMessage; if (metaType == 0x2F) { // end of track means it! endOfTrackFound = true; } break; default: throw new InvalidMidiDataException("Invalid status byte: " + status); } // switch sys-ex or meta break; default: throw new InvalidMidiDataException("Invalid status byte: " + status); } // switch track.add(new MidiEvent(message, tick)); } // while } catch (ArrayIndexOutOfBoundsException e) { if (DEBUG) e.printStackTrace(); // fix for 4834374 throw new EOFException("invalid MIDI file"); } } }