tika-parsers/tika-parsers-standard/tika-parsers-standard-modules/tika-parser-audiovideo-module/src/main/java/org/apache/tika/parser/audio/MidiParser.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.tika.parser.audio;

import static java.nio.charset.StandardCharsets.ISO_8859_1;

import java.io.BufferedInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashSet;
import java.util.Set;
import javax.sound.midi.InvalidMidiDataException;
import javax.sound.midi.MetaMessage;
import javax.sound.midi.MidiMessage;
import javax.sound.midi.MidiSystem;
import javax.sound.midi.Patch;
import javax.sound.midi.Sequence;
import javax.sound.midi.Track;

import org.xml.sax.ContentHandler;
import org.xml.sax.SAXException;

import org.apache.tika.exception.TikaException;
import org.apache.tika.metadata.Metadata;
import org.apache.tika.mime.MediaType;
import org.apache.tika.parser.AbstractParser;
import org.apache.tika.parser.ParseContext;
import org.apache.tika.sax.XHTMLContentHandler;

public class MidiParser extends AbstractParser {

    /**
     * Serial version UID
     */
    private static final long serialVersionUID = 6343278584336189432L;

    private static final Set<MediaType> SUPPORTED_TYPES = Collections.unmodifiableSet(
            new HashSet<>(
                    Arrays.asList(MediaType.application("x-midi"), MediaType.audio("midi"))));

    public Set<MediaType> getSupportedTypes(ParseContext context) {
        return SUPPORTED_TYPES;
    }

    public void parse(InputStream stream, ContentHandler handler, Metadata metadata,
                      ParseContext context) throws IOException, SAXException, TikaException {
        metadata.set(Metadata.CONTENT_TYPE, "audio/midi");

        XHTMLContentHandler xhtml = new XHTMLContentHandler(handler, metadata);
        xhtml.startDocument();

        // MidiSystem expects the stream to support the mark feature
        if (!stream.markSupported()) {
            stream = new BufferedInputStream(stream);
        }
        try {
            Sequence sequence = MidiSystem.getSequence(stream);

            Track[] tracks = sequence.getTracks();
            metadata.set("tracks", String.valueOf(tracks.length));
            // TODO: Use XMPDM.TRACKS?

            Patch[] patches = sequence.getPatchList();
            metadata.set("patches", String.valueOf(patches.length));

            float type = sequence.getDivisionType();
            if (type == Sequence.PPQ) {
                metadata.set("divisionType", "PPQ");
            } else if (type == Sequence.SMPTE_24) {
                metadata.set("divisionType", "SMPTE_24");
            } else if (type == Sequence.SMPTE_25) {
                metadata.set("divisionType", "SMPTE_25");
            } else if (type == Sequence.SMPTE_30) {
                metadata.set("divisionType", "SMPTE_30");
            } else if (type == Sequence.SMPTE_30DROP) {
                metadata.set("divisionType", "SMPTE_30DROP");
            } else if (type == Sequence.SMPTE_24) {
                metadata.set("divisionType", String.valueOf(type));
            }

            for (Track track : tracks) {
                xhtml.startElement("p");
                for (int i = 0; i < track.size(); i++) {
                    MidiMessage message = track.get(i).getMessage();
                    if (message instanceof MetaMessage) {
                        MetaMessage meta = (MetaMessage) message;
                        // Types 1-15 are reserved for text events
                        if (meta.getType() >= 1 && meta.getType() <= 15) {
                            // FIXME: What's the encoding?
                            xhtml.characters(new String(meta.getData(), ISO_8859_1));
                        }
                    }
                }
                xhtml.endElement("p");
            }
        } catch (InvalidMidiDataException ignore) {
            // There is no way to know whether this exception was
            // caused by the document being corrupted or by the format
            // just being unsupported. So we do nothing.
        }

        xhtml.endDocument();
    }

}