/* AUReader.java -- Read AU files.
   Copyright (C) 2006 Free Software Foundation, Inc.

This file is part of GNU Classpath.

GNU Classpath 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 2, or (at your option)
any later version.

GNU Classpath 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 GNU Classpath; see the file COPYING.  If not, write to the
Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301 USA.

Linking this library statically or dynamically with other modules is
making a combined work based on this library.  Thus, the terms and
conditions of the GNU General Public License cover the whole
combination.

As a special exception, the copyright holders of this library give you
permission to link this library with independent modules to produce an
executable, regardless of the license terms of these independent
modules, and to copy and distribute the resulting executable under
terms of your choice, provided that you also meet, for each linked
independent module, the terms and conditions of the license of that
module.  An independent module is a module which is not derived from
or based on this library.  If you modify this library, you may extend
this exception to your version of the library, but you are not
obligated to do so.  If you do not wish to do so, delete this
exception statement from your version. */

package gnu.javax.sound.sampled.AU;

import javax.sound.sampled.AudioFormat;
import javax.sound.sampled.AudioSystem;
import javax.sound.sampled.AudioFileFormat;
import javax.sound.sampled.AudioInputStream;
import javax.sound.sampled.UnsupportedAudioFileException;
import javax.sound.sampled.spi.AudioFileReader;
import java.io.File;
import java.io.IOException;
import java.io.BufferedInputStream;
import java.io.InputStream;
import java.io.DataInputStream;
import java.io.FileInputStream;
import java.net.URL;
import java.nio.ByteBuffer;

public class AUReader extends AudioFileReader
{
  private static class AUHeader
  {
    // Magic number identifying the file. '.snd' 
    private static final int MAGIC = 0x2e736e64;
    
    public static final int SIZE = 24; // size of the header
    
    // Encoding types
    public static final int ULAW = 1; // 8-bit u-law
    public static final int PCM8 = 2; // 8-bit PCM
    public static final int PCM16 = 3; // 16-bit PCM
    public static final int PCM24 = 4; // 24-bit PCM
    public static final int PCM32 = 5; // 32-bit PCM
    public static final int IEEE32 = 6; // 32-bit IEEE f.p.
    public static final int IEEE64 = 7; // 64-bit IEEE f.p.
    public static final int G721 = 23; 
    public static final int G722 = 24; 
    public static final int G723 = 25; 
    public static final int G723_5BIT = 26; 
    public static final int ALAW = 27; // 8-bit a-law

    // Header data.
    public int headerSize;
    public int fileSize; // this value may not be set.
    public int encoding;
    public int sampleRate;
    public int channels;
    public int sampleSizeInBits;

    public AUHeader(InputStream stream)
      throws IOException, UnsupportedAudioFileException
    {
      byte[] hdr = new byte[24];
      stream.read( hdr );
      ByteBuffer buf = ByteBuffer.wrap(hdr);

      if( buf.getInt() != MAGIC )
	throw new UnsupportedAudioFileException("Not an AU format audio file.");
      headerSize = buf.getInt(); 
      fileSize = buf.getInt(); 
      encoding = buf.getInt(); 
      sampleRate = buf.getInt();
      channels = buf.getInt(); 

      switch(encoding)
	{
	case ULAW: 
	case PCM8: 
	case ALAW: 
	  sampleSizeInBits = 8;
	  break;
	case PCM16:
	  sampleSizeInBits = 16;
	  break;
	case PCM24:
	  sampleSizeInBits = 24;
	  break;
	case PCM32:
	  sampleSizeInBits = 32;
	  break;
	default:   // other types exist but are not supported. Yet.
	  throw new UnsupportedAudioFileException("Unsupported encoding.");
	}
    }

  public AudioFormat getAudioFormat()
    {
      AudioFormat.Encoding encType = AudioFormat.Encoding.PCM_SIGNED;
      if(encoding == 1)
	encType = AudioFormat.Encoding.ULAW;
      if(encoding == 27)
	encType = AudioFormat.Encoding.ALAW;
      
      return new AudioFormat(encType, 
			     (float)sampleRate, 
			     sampleSizeInBits, 
			     channels, 
			     (sampleSizeInBits >> 3) * channels, 
			     (float)sampleRate, 
			     true);
    }

  public AudioFileFormat getAudioFileFormat()
    {
      return new AudioFileFormat(new AUFormatType(), 
				 getAudioFormat(), 
				 AudioSystem.NOT_SPECIFIED);
    }
  }

  public static class AUFormatType extends AudioFileFormat.Type
  {
    public AUFormatType()
    {
      super("AU", ".au");
    }
  }

  public AudioFileFormat getAudioFileFormat(File file)
    throws IOException, UnsupportedAudioFileException
  {
    return getAudioFileFormat(new FileInputStream(file));
  }

  public AudioFileFormat getAudioFileFormat(InputStream stream)
    throws IOException, UnsupportedAudioFileException
  {
    if(!stream.markSupported()) 
      throw new IOException("Stream must support marking.");    

    stream.mark(25);
    AUHeader header = new AUHeader(stream);
    stream.reset();

    return header.getAudioFileFormat();
  }
  
  public AudioFileFormat getAudioFileFormat(URL url)
    throws IOException, UnsupportedAudioFileException
  {        
    return getAudioFileFormat(new BufferedInputStream(url.openStream()));
  }

  public AudioInputStream getAudioInputStream(File file)
    throws IOException, UnsupportedAudioFileException
  {
    InputStream stream = new FileInputStream(file);
    long length = file.length();

    AUHeader header = new AUHeader( stream );
    if( header.headerSize > AUHeader.SIZE )
      stream.skip(header.headerSize - AUHeader.SIZE);

    length -= header.headerSize;

    return new AudioInputStream(stream, header.getAudioFormat(), length);
  }

  public AudioInputStream getAudioInputStream(InputStream stream)
    throws IOException, UnsupportedAudioFileException
  {
    AUHeader header = new AUHeader( stream );
    if( header.headerSize > AUHeader.SIZE )
      stream.skip(header.headerSize - AUHeader.SIZE);

    return new AudioInputStream(stream, header.getAudioFormat(), 
				AudioSystem.NOT_SPECIFIED);
  }

  public AudioInputStream getAudioInputStream(URL url)
    throws IOException, UnsupportedAudioFileException
  {
    return getAudioInputStream(new BufferedInputStream(url.openStream()));
  }
}