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package org.jflac.sound.spi;
/**
* libFLAC - Free Lossless Audio Codec library
* Copyright (C) 2001,2002,2003 Josh Coalson
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library 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
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
import java.io.IOException;
import java.io.InputStream;
import javax.sound.sampled.AudioFormat;
import javax.sound.sampled.AudioInputStream;
import org.jflac.util.RingBuffer;
/**
* 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.
*
* @author Marc Gimpel, Wimba S.A. ([email protected])
* @author Florian Bomers
* @version $Revision: 1.5 $
*/
public abstract class RingedAudioInputStream extends AudioInputStream {
/** The default size of the buffer. */
public static final int DEFAULT_BUFFER_SIZE = 2048;
/** The underlying inputStream. */
protected InputStream in;
/**
* The internal buffer array where the data is stored. When necessary, it
* may be replaced by another array of a different size.
*/
//protected byte[] buf;
/**
* 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.
*/
//protected int count;
/**
* 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 #buf
*/
//protected int pos;
/**
* 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 #mark(int)
* @see #pos
*/
//protected int markpos;
/**
* 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 #mark(int)
* @see #reset()
*/
//protected int marklimit;
/**
* Array of size 1, used by the read method to read just 1 byte.
*/
private final byte[] single = new byte[1];
/**
* The internal buffer array where the unfiltered data is temporarily
* stored.
*/
//protected byte[] prebuf;
/**
* 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.
*/
//protected int precount;
/**
* 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 #prebuf
*/
//protected int prepos;
protected RingBuffer buffer = new RingBuffer();
/**
* Check to make sure that this stream has not been closed.
*
* @exception IOException
*/
private void checkIfStillOpen() throws IOException {
if (in == null) throw new IOException("Stream closed");
}
/**
* Creates a RingedAudioInputStream and saves its argument,
* the input stream in, for later use. An internal buffer
* array is created and stored in buf.
*
* @param in
* the underlying input stream.
* @param format
* the format of this stream's audio data.
* @param length
* the length in sample frames of the data in this stream.
*/
public RingedAudioInputStream(InputStream in, AudioFormat format, long length) {
this(in, format, length, DEFAULT_BUFFER_SIZE);
}
/**
* Creates a RingedAudioInputStream 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.
*
* @param in
* the underlying input stream.
* @param format
* the format of this stream's audio data.
* @param length
* the length in sample frames of the data in this stream.
* @param size
* the buffer sizes.
*/
public RingedAudioInputStream(InputStream in, AudioFormat format, long length, int size) {
this(in, format, length, size, size);
}
/**
* Creates a RingedAudioInputStream 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.
*
* @param in
* the underlying input stream.
* @param format
* the format of this stream's audio data.
* @param length
* the length in sample frames of the data in this stream.
* @param size
* the buffer size.
* @param presize
* the prebuffer size.
*/
public RingedAudioInputStream(InputStream in, AudioFormat format, long length, int size, int presize) {
super(in, format, length);
this.in = in;
if (format.getFrameSize() > 0) buffer.resize(format.getFrameSize() * 2);
}
/**
* 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.
*
* @exception IOException
*/
protected void fill() throws IOException {
}
/**
*
*/
/*
protected void makeSpace() {
if (markpos < 0)
pos = 0; // no mark: throw away the buffer
else if (pos >= buf.length) // no room left in buffer
if (markpos > 0) { // can throw away early part of the buffer
int sz = pos - markpos;
System.arraycopy(buf, markpos, buf, 0, sz);
pos = sz;
markpos = 0;
} else if (buf.length >= marklimit) {
markpos = -1; // buffer got too big, invalidate mark
pos = 0; // drop buffer contents
} else { // grow buffer
int nsz = pos * 2;
if (nsz > marklimit) nsz = marklimit;
byte[] nbuf = new byte[nsz];
System.arraycopy(buf, 0, nbuf, 0, pos);
buf = nbuf;
}
count = pos;
}
*/
/**
* See the general contract of the read method of
* InputStream.
*
* @return the next byte of data, or -1 if the end of the
* stream is reached.
* @exception IOException
* if an I/O error occurs.
*/
public synchronized int read() throws IOException {
fill();
if (buffer.get(single, 0, 1) == -1) {
return (-1);
} else {
return (single[0] & 0xFF);
}
}
/**
* Read characters into a portion of an array, reading from the underlying
* stream at most once if necessary.
*/
//private int read1(byte[] b, int off, int len) throws IOException {
// return buffer.get(b, off, len);
//}
/**
* 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
* {@link InputStream#read(byte[], int, int) read} method of
* the {@link 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.
*
* @param b
* destination buffer.
* @param off
* offset at which to start storing bytes.
* @param len
* maximum number of bytes to read.
* @return the number of bytes read, or -1 if the end of the
* stream has been reached.
* @exception IOException
* if an I/O error occurs.
*/
public synchronized int read(byte[] b, int off, int len) throws IOException {
checkIfStillOpen();
int frameSize = (int) getFrameLength();
int bytesRead = 0;
// can only read integral number of frames
len -= (len % frameSize);
// do a best effort to fill the buffer
while (len > 0) {
int thisLen = len;
if (thisLen > buffer.getAvailable()) {
thisLen = buffer.getAvailable();
}
if (thisLen < frameSize) {
fill();
if (buffer.getAvailable() < frameSize) {
break;
}
continue;
}
// can only read integral number of frames
thisLen -= (thisLen % frameSize);
int thisBytesRead = buffer.get(b, off, thisLen);
if (thisBytesRead < frameSize) {
break;
}
off += thisBytesRead;
len -= thisBytesRead;
bytesRead += thisBytesRead;
}
if (bytesRead == 0 && buffer.isEOF()) {
return -1;
}
return bytesRead;
}
/**
* See the general contract of the skip method of
* InputStream.
*
* @param n
* the number of bytes to be skipped.
* @return the actual number of bytes skipped.
* @exception IOException
* if an I/O error occurs.
*/
public synchronized long skip(long n) throws IOException {
checkIfStillOpen();
throw new IOException("skip not supported");
}
/**
* 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).
*
* @return the number of bytes that can be read from this inputstream
* without blocking.
* @exception IOException
* if an I/O error occurs.
*/
public synchronized int available() throws IOException {
checkIfStillOpen();
if (buffer.getAvailable() < (int) getFrameLength()) {
fill();
}
return buffer.getAvailable();
}
/**
* See the general contract of the mark method of
* InputStream.
*
* @param readlimit
* the maximum limit of bytes that can be read before the mark
* position becomes invalid.
* @see #reset()
*/
public synchronized void mark(int readlimit) {
}
/**
* 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.
*
* @exception IOException
* if this stream has not been marked or if the mark has been
* invalidated.
* @see #mark(int)
*/
public synchronized void reset() throws IOException {
checkIfStillOpen();
throw new IOException("reset not supported");
}
/**
* Tests if this input stream supports the mark and
* reset methods. The markSupported method of
* FilteredAudioInputStream returns true.
*
* @return a boolean indicating if this stream type supports
* the mark and reset methods.
* @see #mark(int)
* @see #reset()
*/
public boolean markSupported() {
return false;
}
/**
* Closes this input stream and releases any system resources associated with
* the stream.
*
* @exception IOException if an I/O error occurs.
*/
public synchronized void close() throws IOException {
if (in == null) return;
in.close();
in = null;
}
}