/*

 * Copyright (c) 1999, 2014, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code 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

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

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

 * @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.

 */

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");

        }

    }

}