Class FilteredAudioInputStream

All Implemented Interfaces:
Closeable, AutoCloseable
Direct Known Subclasses:
Pcm2SpeexAudioInputStream, Speex2PcmAudioInputStream

public abstract class FilteredAudioInputStream extends AudioInputStream
A FilteredAudioInputStream is an AudioInputStream with buffers to facilitate transcoding the audio. A first byte array can buffer the data from the underlying inputstream until sufficient data for transcoding is present. A second byte array can hold the transcoded audio data, ready to be read out by the stream user.
Version:
$Revision: 1.2 $
Author:
Marc Gimpel, Wimba S.A. (mgimpel@horizonwimba.com)
  • Field Summary

    Fields
    Modifier and Type
    Field
    Description
    protected byte[]
    The internal buffer array where the data is stored.
    protected int
    The index one greater than the index of the last valid byte in the buffer.
    static final int
    The default size of the buffer.
    protected InputStream
    The underlying inputStream.
    protected int
    The maximum read ahead allowed after a call to the mark method before subsequent calls to the reset method fail.
    protected int
    The value of the pos field at the time the last mark method was called.
    protected int
    The current position in the buffer.
    protected byte[]
    The internal buffer array where the unfiltered data is temporarily stored.
    protected int
    The index one greater than the index of the last valid byte in the unfiltered data buffer.
    protected int
    The current position in the unfiltered data buffer.
    private final byte[]
    Array of size 1, used by the read method to read just 1 byte.

    Fields inherited from class javax.sound.sampled.AudioInputStream

    format, frameLength, framePos, frameSize
  • Constructor Summary

    Constructors
    Constructor
    Description
    Creates a FilteredAudioInputStream and saves its argument, the input stream in, for later use.
    FilteredAudioInputStream(InputStream in, AudioFormat format, long length, int size)
    Creates a FilteredAudioInputStream with the specified buffer size, and saves its argument, the inputstream in for later use.
    FilteredAudioInputStream(InputStream in, AudioFormat format, long length, int size, int presize)
    Creates a FilteredAudioInputStream with the specified buffer size, and saves its argument, the inputstream in for later use.
  • Method Summary

    Modifier and Type
    Method
    Description
    int
    Returns the number of bytes that can be read from this inputstream without blocking.
    protected void
    Check to make sure that this stream has not been closed
    void
    Closes this input stream and releases any system resources associated with the stream.
    protected void
    Fills the buffer with more data, taking into account shuffling and other tricks for dealing with marks.
    protected void
    Free up some space in the buffers.
    void
    mark(int readlimit)
    See the general contract of the mark method of InputStream.
    boolean
    Tests if this input stream supports the mark and reset methods.
    int
    See the general contract of the read method of InputStream.
    int
    read(byte[] b, int off, int len)
    Reads bytes from this byte-input stream into the specified byte array, starting at the given offset.
    void
    See the general contract of the reset method of InputStream.
    long
    skip(long n)
    See the general contract of the skip method of InputStream.

    Methods inherited from class javax.sound.sampled.AudioInputStream

    getFormat, getFrameLength, read

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
  • Field Details

    • DEFAULT_BUFFER_SIZE

      public static final int DEFAULT_BUFFER_SIZE
      The default size of the buffer.
      See Also:
    • in

      protected InputStream in
      The underlying inputStream.
    • buf

      protected byte[] buf
      The internal buffer array where the data is stored. When necessary, it may be replaced by another array of a different size.
    • count

      protected int count
      The index one greater than the index of the last valid byte in the buffer. This value is always in the range 0 through buf.length; elements buf[0] through buf[count-1] contain buffered input data obtained and filtered from the underlying inputstream.
    • pos

      protected int pos
      The current position in the buffer. This is the index of the next character to be read from the buf array.

      This value is always in the range 0 through count. If it is less than count, then buf[pos] is the next byte to be supplied as input. If it is equal to count, then the next read or skip operation will require more bytes to be read and filtered from the underlying inputstream.

      See Also:
    • markpos

      protected int markpos
      The value of the pos field at the time the last mark method was called.

      This value is always in the range -1 through pos. If there is no marked position in the inputstream, this field is -1. If there is a marked position in the inputstream, then buf[markpos] is the first byte to be supplied as input after a reset operation. If markpos is not -1, then all bytes from positions buf[markpos] through buf[pos-1] must remain in the buffer array (though they may be moved to another place in the buffer array, with suitable adjustments to the values of count, pos, and markpos); they may not be discarded unless and until the difference between pos and markpos exceeds marklimit.

      See Also:
    • marklimit

      protected int marklimit
      The maximum read ahead allowed after a call to the mark method before subsequent calls to the reset method fail. Whenever the difference between pos and markpos exceeds marklimit, then the mark may be dropped by setting markpos to -1.
      See Also:
    • single

      private final byte[] single
      Array of size 1, used by the read method to read just 1 byte.
    • prebuf

      protected byte[] prebuf
      The internal buffer array where the unfiltered data is temporarily stored.
    • precount

      protected int precount
      The index one greater than the index of the last valid byte in the unfiltered data buffer. This value is always in the range 0 through prebuf.length; elements prebuf[0] through prebuf[count-1] contain buffered input data obtained from the underlying input stream.
    • prepos

      protected int prepos
      The current position in the unfiltered data buffer. This is the index of the next character to be read from the prebuf array.

      This value is always in the range 0 through precount. If it is less than precount, then prebuf[pos] is the next byte to be supplied as input. If it is equal to precount, then the next read or skip operation will require more bytes to be read from the contained inputstream.

      See Also:
  • Constructor Details

    • FilteredAudioInputStream

      public FilteredAudioInputStream(InputStream in, AudioFormat format, long length)
      Creates a FilteredAudioInputStream and saves its argument, the input stream in, for later use. An internal buffer array is created and stored in buf.
      Parameters:
      in - the underlying input stream.
      format - the format of this stream's audio data.
      length - the length in sample frames of the data in this stream.
      Throws:
      IllegalArgumentException - if size invalid input: '<'= 0 or presize invalid input: '<'= 0.
    • FilteredAudioInputStream

      public FilteredAudioInputStream(InputStream in, AudioFormat format, long length, int size)
      Creates a FilteredAudioInputStream with the specified buffer size, and saves its argument, the inputstream in for later use. An internal buffer array of length size is created and stored in buf.
      Parameters:
      in - the underlying input stream.
      format - the format of this stream's audio data.
      length - the length in sample frames of the data in this stream.
      size - the buffer sizes.
      Throws:
      IllegalArgumentException - if size invalid input: '<'= 0.
    • FilteredAudioInputStream

      public FilteredAudioInputStream(InputStream in, AudioFormat format, long length, int size, int presize)
      Creates a FilteredAudioInputStream with the specified buffer size, and saves its argument, the inputstream in for later use. An internal buffer array of length size is created and stored in buf.
      Parameters:
      in - the underlying input stream.
      format - the format of this stream's audio data.
      length - the length in sample frames of the data in this stream.
      size - the buffer size.
      presize - the prebuffer size.
      Throws:
      IllegalArgumentException - if size invalid input: '<'= 0 or presize invalid input: '<'= 0.
  • Method Details

    • checkIfStillOpen

      protected void checkIfStillOpen() throws IOException
      Check to make sure that this stream has not been closed
      Throws:
      IOException
    • fill

      protected void fill() throws IOException
      Fills the buffer with more data, taking into account shuffling and other tricks for dealing with marks. Assumes that it is being called by a synchronized method. This method also assumes that all data has already been read in, hence pos > count.
      Throws:
      IOException
    • makeSpace

      protected void makeSpace()
      Free up some space in the buffers.
    • read

      public int read() throws IOException
      See the general contract of the read method of InputStream.
      Overrides:
      read in class AudioInputStream
      Returns:
      the next byte of data, or -1 if the end of the stream is reached.
      Throws:
      IOException - if an I/O error occurs.
      See Also:
    • read

      public int read(byte[] b, int off, int len) throws IOException
      Reads bytes from this byte-input stream into the specified byte array, starting at the given offset.

      This method implements the general contract of the corresponding read method of the InputStream class. As an additional convenience, it attempts to read as many bytes as possible by repeatedly invoking the read method of the underlying stream. This iterated read continues until one of the following conditions becomes true:

      • The specified number of bytes have been read,
      • The read method of the underlying stream returns -1, indicating end-of-file, or
      • The available method of the underlying stream returns zero, indicating that further input requests would block.
      If the first read on the underlying stream returns -1 to indicate end-of-file then this method returns -1. Otherwise this method returns the number of bytes actually read.

      Subclasses of this class are encouraged, but not required, to attempt to read as many bytes as possible in the same fashion.

      Overrides:
      read in class AudioInputStream
      Parameters:
      b - destination buffer.
      off - offset at which to start storing bytes.
      len - maximum number of bytes to read.
      Returns:
      the number of bytes read, or -1 if the end of the stream has been reached.
      Throws:
      IOException - if an I/O error occurs.
    • skip

      public long skip(long n) throws IOException
      See the general contract of the skip method of InputStream.
      Overrides:
      skip in class AudioInputStream
      Parameters:
      n - the number of bytes to be skipped.
      Returns:
      the actual number of bytes skipped.
      Throws:
      IOException - if an I/O error occurs.
    • available

      public int available() throws IOException
      Returns the number of bytes that can be read from this inputstream without blocking.

      The available method of FilteredAudioInputStream returns the sum of the the number of bytes remaining to be read in the buffer (count - pos). The result of calling the available method of the underlying inputstream is not used, as this data will have to be filtered, and thus may not be the same size after processing (although subclasses that do the filtering should override this method and use the amount of data available in the underlying inputstream).

      Overrides:
      available in class AudioInputStream
      Returns:
      the number of bytes that can be read from this inputstream without blocking.
      Throws:
      IOException - if an I/O error occurs.
      See Also:
    • mark

      public void mark(int readlimit)
      See the general contract of the mark method of InputStream.
      Overrides:
      mark in class AudioInputStream
      Parameters:
      readlimit - the maximum limit of bytes that can be read before the mark position becomes invalid.
      See Also:
    • reset

      public void reset() throws IOException
      See the general contract of the reset method of InputStream.

      If markpos is -1 (no mark has been set or the mark has been invalidated), an IOException is thrown. Otherwise, pos is set equal to markpos.

      Overrides:
      reset in class AudioInputStream
      Throws:
      IOException - if this stream has not been marked or if the mark has been invalidated.
      See Also:
    • markSupported

      public boolean markSupported()
      Tests if this input stream supports the mark and reset methods. The markSupported method of FilteredAudioInputStream returns true.
      Overrides:
      markSupported in class AudioInputStream
      Returns:
      a boolean indicating if this stream type supports the mark and reset methods.
      See Also:
    • close

      public void close() throws IOException
      Closes this input stream and releases any system resources associated with the stream.
      Specified by:
      close in interface AutoCloseable
      Specified by:
      close in interface Closeable
      Overrides:
      close in class AudioInputStream
      Throws:
      IOException - if an I/O error occurs.