/******************************************************************************
 *                                                                            *
 * Copyright (c) 1999-2003 Wimba S.A., All Rights Reserved.                   *
 *                                                                            *
 * COPYRIGHT:                                                                 *
 *      This software is the property of Wimba S.A.                           *
 *      This software is redistributed under the Xiph.org variant of          *
 *      the BSD license.                                                      *
 *      Redistribution and use in source and binary forms, with or without    *
 *      modification, are permitted provided that the following conditions    *
 *      are met:                                                              *
 *      - Redistributions of source code must retain the above copyright      *
 *      notice, this list of conditions and the following disclaimer.         *
 *      - Redistributions in binary form must reproduce the above copyright   *
 *      notice, this list of conditions and the following disclaimer in the   *
 *      documentation and/or other materials provided with the distribution.  *
 *      - Neither the name of Wimba, the Xiph.org Foundation nor the names of *
 *      its contributors may be used to endorse or promote products derived   *
 *      from this software without specific prior written permission.         *
 *                                                                            *
 * WARRANTIES:                                                                *
 *      This software is made available by the authors in the hope            *
 *      that it will be useful, but without any warranty.                     *
 *      Wimba S.A. is not liable for any consequence related to the           *
 *      use of the provided software.                                         *
 *                                                                            *
 * Class: SpeexAudioFileReader.java                                           *
 *                                                                            *
 * Author: Marc GIMPEL                                                        *
 *                                                                            *
 * Date: 12th July 2003                                                       *
 *                                                                            *
 ******************************************************************************/

/* $Id: SpeexAudioFileReader.java,v 1.2 2004/10/21 16:21:58 mgimpel Exp $ */

package org.xiph.speex.spi;

import  java.io.File;
import  java.io.InputStream;
import  java.io.IOException;
import  java.io.DataInputStream;
import  java.io.FileInputStream;
import  java.io.SequenceInputStream;
import  java.io.ByteArrayInputStream;
import  java.io.ByteArrayOutputStream;
import  java.net.URL;

import  javax.sound.sampled.AudioSystem;
import  javax.sound.sampled.AudioFormat;
import  javax.sound.sampled.AudioFileFormat;
import  javax.sound.sampled.AudioInputStream;
import  javax.sound.sampled.UnsupportedAudioFileException;
import  javax.sound.sampled.spi.AudioFileReader;

import  org.xiph.speex.OggCrc;

/**
 * Provider for Speex audio file reading services.
 * This implementation can parse the format information from Speex audio file,
 * and can produce audio input streams from files of this type.
 * 
 * @author Marc Gimpel, Wimba S.A. (mgimpel@horizonwimba.com)
 * @version $Revision: 1.2 $
 */
public class SpeexAudioFileReader
  extends AudioFileReader
{
  /** */
  public static final int    OGG_HEADERSIZE   = 27;
  /** The size of the Speex header. */
  public static final int    SPEEX_HEADERSIZE = 80;
  /** */
  public static final int    SEGOFFSET        = 26;
  /** The String that identifies the beginning of an Ogg packet. */
  public static final String OGGID            = "OggS";
  /** The String that identifies the beginning of the Speex header. */
  public static final String SPEEXID          = "Speex   ";

  /**
   * Obtains the audio file format of the File provided.
   * The File must point to valid audio file data.
   * @param file the File from which file format information should be
   * extracted.
   * @return an AudioFileFormat object describing the audio file format.
   * @exception UnsupportedAudioFileException if the File does not point to
   * a valid audio file data recognized by the system.
   * @exception IOException if an I/O exception occurs.
   */
  public AudioFileFormat getAudioFileFormat(final File file)
    throws UnsupportedAudioFileException, IOException
  {
    InputStream inputStream = null;
    try {
      inputStream = new FileInputStream(file);
      return getAudioFileFormat(inputStream, (int) file.length());
    }
    finally {
      inputStream.close();
    }
  }

  /**
   * Obtains an audio input stream from the URL provided.
   * The URL must point to valid audio file data.
   * @param url the URL for which the AudioInputStream should be constructed.
   * @return an AudioInputStream object based on the audio file data pointed to
   * by the URL.
   * @exception UnsupportedAudioFileException if the File does not point to
   * a valid audio file data recognized by the system.
   * @exception IOException if an I/O exception occurs.
   */
  public AudioFileFormat getAudioFileFormat(final URL url)
    throws UnsupportedAudioFileException, IOException
  {
    InputStream inputStream = url.openStream();
    try {
      return getAudioFileFormat(inputStream);
    }
    finally {
      inputStream.close();
    }
  }

  /**
   * Obtains an audio input stream from the input stream provided.
   * @param stream the input stream from which the AudioInputStream should be
   * constructed.
   * @return an AudioInputStream object based on the audio file data contained
   * in the input stream.
   * @exception UnsupportedAudioFileException if the File does not point to
   * a valid audio file data recognized by the system.
   * @exception IOException if an I/O exception occurs.
   */
  public AudioFileFormat getAudioFileFormat(final InputStream stream)
    throws UnsupportedAudioFileException, IOException
  {
    return getAudioFileFormat(stream, AudioSystem.NOT_SPECIFIED);
  }

  /**
   * Return the AudioFileFormat from the given InputStream.
   * @param stream the input stream from which the AudioInputStream should be
   * constructed.
   * @param medialength
   * @return an AudioInputStream object based on the audio file data contained
   * in the input stream.
   * @exception UnsupportedAudioFileException if the File does not point to
   * a valid audio file data recognized by the system.
   * @exception IOException if an I/O exception occurs.
   */
  protected AudioFileFormat getAudioFileFormat(final InputStream stream,
                                               final int medialength)
    throws UnsupportedAudioFileException, IOException
  {
    return getAudioFileFormat(stream, null, medialength);
  }

  /**
   * Return the AudioFileFormat from the given InputStream. Implementation.
   * @param bitStream
   * @param baos
   * @param mediaLength
   * @return an AudioInputStream object based on the audio file data contained
   * in the input stream.
   * @exception UnsupportedAudioFileException if the File does not point to
   * a valid audio file data recognized by the system.
   * @exception IOException if an I/O exception occurs.
   */
  protected AudioFileFormat getAudioFileFormat(final InputStream bitStream,
                                               ByteArrayOutputStream baos,
                                               final int mediaLength)
    throws UnsupportedAudioFileException, IOException
  {
    AudioFormat format;
    try {
      // If we can't read the format of this stream, we must restore stream to
      // beginning so other providers can attempt to read the stream.
      if (bitStream.markSupported()) {
        // maximum number of bytes to determine the stream encoding:
        // Size of 1st Ogg Packet (Speex header) = OGG_HEADERSIZE + SPEEX_HEADERSIZE + 1
        // Size of 2nd Ogg Packet (Comment)      = OGG_HEADERSIZE + comment_size + 1
        // Size of 3rd Ogg Header (First data)   = OGG_HEADERSIZE + number_of_frames
        // where number_of_frames < 256 and comment_size < 256 (if within 1 frame)
        bitStream.mark(3*OGG_HEADERSIZE + SPEEX_HEADERSIZE + 256 + 256 + 2);
      }

      int mode        = -1;
      int sampleRate  = 0;
      int channels    = 0;
      int frameSize   = AudioSystem.NOT_SPECIFIED;
      float frameRate = AudioSystem.NOT_SPECIFIED;
      byte[] header   = new byte[128];
      int segments    = 0;
      int bodybytes   = 0; 
      DataInputStream dis = new DataInputStream(bitStream);
      if (baos == null)
        baos = new ByteArrayOutputStream(128);
      int origchksum;
      int chksum;
      // read the OGG header
      dis.readFully(header, 0, OGG_HEADERSIZE);
      baos.write(header, 0, OGG_HEADERSIZE);
      origchksum = readInt(header, 22);
      header[22] = 0;
      header[23] = 0;
      header[24] = 0;
      header[25] = 0;
      chksum=OggCrc.checksum(0, header, 0, OGG_HEADERSIZE);
      // make sure its a OGG header
      if (!OGGID.equals(new String(header, 0, 4))) {
        throw new UnsupportedAudioFileException("missing ogg id!");
      }
      // how many segments are there?
      segments = header[SEGOFFSET] & 0xFF;
      if (segments > 1) {
        throw new UnsupportedAudioFileException("Corrupt Speex Header: more than 1 segments");
      }
      dis.readFully(header, OGG_HEADERSIZE, segments);
      baos.write(header, OGG_HEADERSIZE, segments);
      chksum=OggCrc.checksum(chksum, header, OGG_HEADERSIZE, segments);
      // get the number of bytes in the segment
      bodybytes = header[OGG_HEADERSIZE] & 0xFF;
      if (bodybytes!=SPEEX_HEADERSIZE) {
        throw new UnsupportedAudioFileException("Corrupt Speex Header: size=" + bodybytes);
      }
      // read the Speex header
      dis.readFully(header, OGG_HEADERSIZE+1, bodybytes);
      baos.write(header, OGG_HEADERSIZE+1, bodybytes);
      chksum=OggCrc.checksum(chksum, header, OGG_HEADERSIZE+1, bodybytes);
      // make sure its a Speex header
      if (!SPEEXID.equals(new String(header, OGG_HEADERSIZE+1, 8))) {
        throw new UnsupportedAudioFileException("Corrupt Speex Header: missing Speex ID");
      }
      mode        = readInt(header, OGG_HEADERSIZE+1+40);
      sampleRate  = readInt(header, OGG_HEADERSIZE+1+36);
      channels    = readInt(header, OGG_HEADERSIZE+1+48);
      int nframes = readInt(header, OGG_HEADERSIZE+1+64);
      boolean vbr = readInt(header, OGG_HEADERSIZE+1+60) == 1;
      // Checksum
      if (chksum != origchksum)
        throw new IOException("Ogg CheckSums do not match");
      // Calculate frameSize
      if (!vbr) {
        // Frames size is a constant so:
        // Read Comment Packet the Ogg Header of 1st data packet;
        // the array table_segment repeats the frame size over and over.
      }
      // Calculate frameRate
      if (mode >= 0 && mode <= 2 && nframes > 0) {
        frameRate = ((float) sampleRate) /
                    ((mode == 0 ? 160f : (mode == 1 ? 320f : 640f)) * ((float) nframes));
      }
      format = new AudioFormat(SpeexEncoding.SPEEX, (float)sampleRate,
                               AudioSystem.NOT_SPECIFIED, channels, frameSize,
                               frameRate, false);
    }
    catch(UnsupportedAudioFileException e) {
      // reset the stream for other providers
      if (bitStream.markSupported()) {
        bitStream.reset();
      }
      // just rethrow this exception
      throw e;
    }
    catch (IOException ioe) {
      // reset the stream for other providers
      if (bitStream.markSupported()) {
        bitStream.reset();
      }
      throw new UnsupportedAudioFileException(ioe.getMessage());
    }
    return new AudioFileFormat(SpeexFileFormatType.SPEEX, format,
                               AudioSystem.NOT_SPECIFIED);
  }

  /**
   * Obtains an audio input stream from the File provided.
   * The File must point to valid audio file data.
   * @param file the File for which the AudioInputStream should be constructed.
   * @return an AudioInputStream object based on the audio file data pointed to
   * by the File.
   * @exception UnsupportedAudioFileException if the File does not point to
   * a valid audio file data recognized by the system.
   * @exception IOException if an I/O exception occurs.
   */
  public AudioInputStream getAudioInputStream(final File file)
    throws UnsupportedAudioFileException, IOException
  {
    InputStream inputStream = new FileInputStream(file);
    try {
      return getAudioInputStream(inputStream, (int) file.length());
    }
    catch (UnsupportedAudioFileException e) {
      inputStream.close();
      throw e;
    }
    catch (IOException e) {
      inputStream.close();
      throw e;
    }
  }

  /**
   * Obtains an audio input stream from the URL provided.
   * The URL must point to valid audio file data.
   * @param url the URL for which the AudioInputStream should be constructed.
   * @return an AudioInputStream object based on the audio file data pointed to
   * by the URL.
   * @exception UnsupportedAudioFileException if the File does not point to
   * a valid audio file data recognized by the system.
   * @exception IOException if an I/O exception occurs.
   */
  public AudioInputStream getAudioInputStream(final URL url)
    throws UnsupportedAudioFileException, IOException
  {
    InputStream inputStream = url.openStream();
    try {
      return getAudioInputStream(inputStream);
    }
    catch (UnsupportedAudioFileException e) {
      inputStream.close();
      throw e;
    }
    catch (IOException e) {
      inputStream.close();
      throw e;
    }
  }

  /**
   * Obtains an audio input stream from the input stream provided.
   * The stream must point to valid audio file data.
   * @param stream the input stream from which the AudioInputStream should be
   * constructed.
   * @return an AudioInputStream object based on the audio file data contained
   * in the input stream.
   * @exception UnsupportedAudioFileException if the File does not point to
   * a valid audio file data recognized by the system.
   * @exception IOException if an I/O exception occurs.
   */
  public AudioInputStream getAudioInputStream(final InputStream stream)
    throws UnsupportedAudioFileException, IOException
  {
    return getAudioInputStream(stream, AudioSystem.NOT_SPECIFIED);
  }

  /**
   * Obtains an audio input stream from the input stream provided.
   * The stream must point to valid audio file data.
   * @param inputStream the input stream from which the AudioInputStream should
   * be constructed.
   * @param medialength
   * @return an AudioInputStream object based on the audio file data contained
   * in the input stream.
   * @exception UnsupportedAudioFileException if the File does not point to
   * a valid audio file data recognized by the system.
   * @exception IOException if an I/O exception occurs.
   */
  protected AudioInputStream getAudioInputStream(final InputStream inputStream,
                                                 final int medialength)
    throws UnsupportedAudioFileException, IOException
  {
    ByteArrayOutputStream baos = new ByteArrayOutputStream(128);
    AudioFileFormat audioFileFormat = getAudioFileFormat(inputStream,
                                                         baos,
                                                         medialength);
    ByteArrayInputStream bais = new ByteArrayInputStream(baos.toByteArray());
    SequenceInputStream sequenceInputStream = new SequenceInputStream(bais, inputStream);
    return new AudioInputStream(sequenceInputStream,
                                audioFileFormat.getFormat(),
                                audioFileFormat.getFrameLength());
  }

  /**
   * Converts Little Endian (Windows) bytes to an int (Java uses Big Endian).
   * @param data the data to read.
   * @param offset the offset from which to start reading.
   * @return the integer value of the reassembled bytes.
   */
  private static int readInt(final byte[] data, final int offset)
  {
    return (data[offset] & 0xff) |
           ((data[offset+1] & 0xff) <<  8) |
           ((data[offset+2] & 0xff) << 16) |
           (data[offset+3] << 24); // no & 0xff at the end to keep the sign
  }
}