net.pterodactylus.sonitus.io.IdentifyingInputStream.java Source code

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Here is the source code for net.pterodactylus.sonitus.io.IdentifyingInputStream.java

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/*
 * Sonitus - IdentifyingStream.java - Copyright  2013 David Roden
 *
 * 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 3 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, see <http://www.gnu.org/licenses/>.
 */

package net.pterodactylus.sonitus.io;

import java.io.EOFException;
import java.io.FilterInputStream;
import java.io.IOException;
import java.io.InputStream;

import net.pterodactylus.sonitus.data.Metadata;

import com.google.common.base.Optional;
import com.google.common.io.ByteStreams;

/**
 * Wrapper around an {@link InputStream} that identifies the {@link Metadata} of
 * the wrapped stream.
 *
 * @author <a href="mailto:bombe@pterodactylus.net">David Bombe Roden</a>
 */
public class IdentifyingInputStream extends FilterInputStream {

    /** The identified metadata. */
    private final Metadata metadata;

    /**
     * Creates a new identifying input stream.
     *
     * @param inputStream
     *       The input stream to wrap
     * @param metadata
     *       The metadata of the stream
     */
    private IdentifyingInputStream(InputStream inputStream, Metadata metadata) {
        super(inputStream);
        this.metadata = metadata;
    }

    //
    // ACCESSORS
    //

    /**
     * Returns the identified metadata.
     *
     * @return The identified metadata
     */
    public Metadata metadata() {
        return metadata;
    }

    //
    // STATIC METHODS
    //

    /**
     * Tries to identify the given input stream.
     *
     * @param inputStream
     *       The input stream to identify
     * @return An identifying input stream that delivers the original stream and
     *         the metadata it detected, or {@link Optional#absent()} if no
     *         metadata could be identified
     * @throws IOException
     *       if an I/O error occurs
     */
    public static Optional<IdentifyingInputStream> create(InputStream inputStream) throws IOException {

        /* remember everything we read here. */
        RememberingInputStream rememberingInputStream = new RememberingInputStream(inputStream);

        /* first, try formats with unambiguous layouts. */
        try {
            Optional<Metadata> metadata = FlacIdentifier.identify(rememberingInputStream);
            if (metadata.isPresent()) {
                return Optional.of(new IdentifyingInputStream(rememberingInputStream.remembered(), metadata.get()));
            }
        } catch (EOFException eofe1) {
            /* ignore. */
        }

        /* try Ogg Vorbis next. */
        try {
            rememberingInputStream = new RememberingInputStream(rememberingInputStream.remembered());
            Optional<Metadata> metadata = OggVorbisIdentifier.identify(rememberingInputStream);
            if (metadata.isPresent()) {
                return Optional.of(new IdentifyingInputStream(rememberingInputStream.remembered(), metadata.get()));
            }
        } catch (EOFException eofe1) {
            /* ignore. */
        }

        /* finally, try MP3. */
        try {
            rememberingInputStream = new RememberingInputStream(rememberingInputStream.remembered());
            InputStream limitedInputStream = ByteStreams.limit(rememberingInputStream, 1048576);
            Optional<Metadata> metadata = Mp3Identifier.identify(limitedInputStream);
            if (metadata.isPresent()) {
                return Optional.of(new IdentifyingInputStream(rememberingInputStream.remembered(), metadata.get()));
            }
        } catch (EOFException eofe1) {
            /* ignore. */
        }

        return Optional.absent();
    }

}