src/main/java/net/pterodactylus/sonitus/io/IdentifyingInputStream.java

   1 /*
   2  * Sonitus - IdentifyingStream.java - Copyright © 2013 David Roden
   3  *
   4  * This program is free software: you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation, either version 3 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  16  */
  17
  18 package net.pterodactylus.sonitus.io;
  19
  20 import java.io.FilterInputStream;
  21 import java.io.IOException;
  22 import java.io.InputStream;
  23
  24 import net.pterodactylus.sonitus.data.Metadata;
  25
  26 import com.google.common.base.Optional;
  27 import com.google.common.io.ByteStreams;
  28
  29 /**
  30  * Wrapper around an {@link InputStream} that identifies the {@link Metadata} of
  31  * the wrapped stream.
  32  *
  33  * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
  34  */
  35 public class IdentifyingInputStream extends FilterInputStream {
  36
  37         /** The identified metadata. */
  38         private final Metadata metadata;
  39
  40         /**
  41          * Creates a new identifying input stream.
  42          *
  43          * @param inputStream
  44          *              The input stream to wrap
  45          * @param metadata
  46          *              The metadata of the stream
  47          */
  48         private IdentifyingInputStream(InputStream inputStream, Metadata metadata) {
  49                 super(inputStream);
  50                 this.metadata = metadata;
  51         }
  52
  53         //
  54         // ACCESSORS
  55         //
  56
  57         /**
  58          * Returns the identified metadata.
  59          *
  60          * @return The identified metadata
  61          */
  62         public Metadata metadata() {
  63                 return metadata;
  64         }
  65
  66         //
  67         // STATIC METHODS
  68         //
  69
  70         /**
  71          * Tries to identify the given input stream.
  72          *
  73          * @param inputStream
  74          *              The input stream to identify
  75          * @return An identifying input stream that delivers the original stream and
  76          *         the metadata it detected, or {@link Optional#absent()} if no
  77          *         metadata could be identified
  78          * @throws IOException
  79          *              if an I/O error occurs
  80          */
  81         public static Optional<IdentifyingInputStream> create(InputStream inputStream) throws IOException {
  82
  83                 /* remember everything we read here. */
  84                 RememberingInputStream rememberingInputStream = new RememberingInputStream(inputStream);
  85
  86                 /* try Ogg Vorbis first. */
  87                 Optional<Metadata> metadata = OggVorbisIdentifier.identify(rememberingInputStream);
  88                 if (metadata.isPresent()) {
  89                         return Optional.of(new IdentifyingInputStream(rememberingInputStream.remembered(), metadata.get()));
  90                 }
  91
  92                 /* try MP3 now. */
  93                 rememberingInputStream = new RememberingInputStream(rememberingInputStream.remembered());
  94                 InputStream limitedInputStream = ByteStreams.limit(rememberingInputStream, 1048576);
  95                 metadata = Mp3Identifier.identify(limitedInputStream);
  96                 if (metadata.isPresent()) {
  97                         return Optional.of(new IdentifyingInputStream(rememberingInputStream.remembered(), metadata.get()));
  98                 }
  99
 100                 return Optional.absent();
 101         }
 102
 103 }