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

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

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/*
 * Sonitus - FlacIdentifier.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 static net.pterodactylus.sonitus.io.flac.BlockType.STREAMINFO;

import java.io.IOException;
import java.io.InputStream;
import java.util.List;

import net.pterodactylus.sonitus.data.ContentMetadata;
import net.pterodactylus.sonitus.data.FormatMetadata;
import net.pterodactylus.sonitus.data.Metadata;
import net.pterodactylus.sonitus.io.flac.MetadataBlock;
import net.pterodactylus.sonitus.io.flac.Stream;
import net.pterodactylus.sonitus.io.flac.StreamInfo;

import com.google.common.base.Optional;

/**
 * An identifier for FLAC input streams.
 *
 * @author <a href="mailto:bombe@pterodactylus.net">David Bombe Roden</a>
 */
public class FlacIdentifier {

    /**
     * Tries to identify the FLAC file contained in the given stream.
     *
     * @param inputStream
     *       The input stream
     * @return The identified metadata, or {@link Optional#absent()} if the
     *         metadata can not be identified
     * @throws IOException
     *       if an I/O error occurs
     */
    public static Optional<Metadata> identify(InputStream inputStream) throws IOException {
        Optional<Stream> stream = Stream.parse(inputStream);
        if (!stream.isPresent()) {
            return Optional.absent();
        }

        List<MetadataBlock> streamInfos = stream.get().metadataBlocks(STREAMINFO);
        if (streamInfos.isEmpty()) {
            /* FLAC file without STREAMINFO is invalid. */
            return Optional.absent();
        }

        MetadataBlock streamInfoBlock = streamInfos.get(0);
        StreamInfo streamInfo = (StreamInfo) streamInfoBlock.data();

        return Optional
                .of(new Metadata(new FormatMetadata(streamInfo.numberOfChannels(), streamInfo.sampleRate(), "FLAC"),
                        new ContentMetadata()));
    }

}