JDK8/Java8源码在线阅读
/*
* Copyright (c) 1999, 2013, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code 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
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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package com.sun.media.sound;
import java.io.IOException;
import java.util.Vector;
import javax.sound.sampled.AudioFormat;
import javax.sound.sampled.AudioSystem;
import javax.sound.sampled.AudioInputStream;
/**
* U-law encodes linear data, and decodes u-law data to linear data.
*
* @author Kara Kytle
*/
public final class UlawCodec extends SunCodec {
/* Tables used for U-law decoding */
private final static byte[] ULAW_TABH = new byte[256];
private final static byte[] ULAW_TABL = new byte[256];
private static final AudioFormat.Encoding[] ulawEncodings = {AudioFormat.Encoding.ULAW,
AudioFormat.Encoding.PCM_SIGNED};
private static final short seg_end [] = {0xFF, 0x1FF, 0x3FF,
0x7FF, 0xFFF, 0x1FFF, 0x3FFF, 0x7FFF};
/**
* Initializes the decode tables
*/
static {
for (int i=0;i<256;i++) {
int ulaw = ~i;
int t;
ulaw &= 0xFF;
t = ((ulaw & 0xf)<<3) + 132;
t <<= ((ulaw & 0x70) >> 4);
t = ( (ulaw&0x80) != 0 ) ? (132-t) : (t-132);
ULAW_TABL[i] = (byte) (t&0xff);
ULAW_TABH[i] = (byte) ((t>>8) & 0xff);
}
}
/**
* Constructs a new ULAW codec object.
*/
public UlawCodec() {
super(ulawEncodings, ulawEncodings);
}
/**
*/
public AudioFormat.Encoding[] getTargetEncodings(AudioFormat sourceFormat){
if( AudioFormat.Encoding.PCM_SIGNED.equals(sourceFormat.getEncoding()) ) {
if( sourceFormat.getSampleSizeInBits() == 16 ) {
AudioFormat.Encoding enc[] = new AudioFormat.Encoding[1];
enc[0] = AudioFormat.Encoding.ULAW;
return enc;
} else {
return new AudioFormat.Encoding[0];
}
} else if (AudioFormat.Encoding.ULAW.equals(sourceFormat.getEncoding())) {
if (sourceFormat.getSampleSizeInBits() == 8) {
AudioFormat.Encoding enc[] = new AudioFormat.Encoding[1];
enc[0] = AudioFormat.Encoding.PCM_SIGNED;
return enc;
} else {
return new AudioFormat.Encoding[0];
}
} else {
return new AudioFormat.Encoding[0];
}
}
/**
*/
public AudioFormat[] getTargetFormats(AudioFormat.Encoding targetEncoding, AudioFormat sourceFormat){
if( (AudioFormat.Encoding.PCM_SIGNED.equals(targetEncoding)
&& AudioFormat.Encoding.ULAW.equals(sourceFormat.getEncoding()))
||
(AudioFormat.Encoding.ULAW.equals(targetEncoding)
&& AudioFormat.Encoding.PCM_SIGNED.equals(sourceFormat.getEncoding()))) {
return getOutputFormats(sourceFormat);
} else {
return new AudioFormat[0];
}
}
/**
*/
public AudioInputStream getAudioInputStream(AudioFormat.Encoding targetEncoding, AudioInputStream sourceStream){
AudioFormat sourceFormat = sourceStream.getFormat();
AudioFormat.Encoding sourceEncoding = sourceFormat.getEncoding();
if (sourceEncoding.equals(targetEncoding)) {
return sourceStream;
} else {
AudioFormat targetFormat = null;
if (!isConversionSupported(targetEncoding,sourceStream.getFormat())) {
throw new IllegalArgumentException("Unsupported conversion: " + sourceStream.getFormat().toString() + " to " + targetEncoding.toString());
}
if (AudioFormat.Encoding.ULAW.equals(sourceEncoding) &&
AudioFormat.Encoding.PCM_SIGNED.equals(targetEncoding) ) {
targetFormat = new AudioFormat( targetEncoding,
sourceFormat.getSampleRate(),
16,
sourceFormat.getChannels(),
2*sourceFormat.getChannels(),
sourceFormat.getSampleRate(),
sourceFormat.isBigEndian());
} else if (AudioFormat.Encoding.PCM_SIGNED.equals(sourceEncoding) &&
AudioFormat.Encoding.ULAW.equals(targetEncoding)) {
targetFormat = new AudioFormat( targetEncoding,
sourceFormat.getSampleRate(),
8,
sourceFormat.getChannels(),
sourceFormat.getChannels(),
sourceFormat.getSampleRate(),
false);
} else {
throw new IllegalArgumentException("Unsupported conversion: " + sourceStream.getFormat().toString() + " to " + targetEncoding.toString());
}
return getAudioInputStream( targetFormat, sourceStream );
}
}
/**
* use old code...
*/
public AudioInputStream getAudioInputStream(AudioFormat targetFormat, AudioInputStream sourceStream){
return getConvertedStream(targetFormat, sourceStream);
}
// OLD CODE
/**
* Opens the codec with the specified parameters.
* @param stream stream from which data to be processed should be read
* @param outputFormat desired data format of the stream after processing
* @return stream from which processed data may be read
* @throws IllegalArgumentException if the format combination supplied is
* not supported.
*/
/* public AudioInputStream getConvertedStream(AudioFormat outputFormat, AudioInputStream stream) { */
private AudioInputStream getConvertedStream(AudioFormat outputFormat, AudioInputStream stream) {
AudioInputStream cs = null;
AudioFormat inputFormat = stream.getFormat();
if( inputFormat.matches(outputFormat) ) {
cs = stream;
} else {
cs = (AudioInputStream) (new UlawCodecStream(stream, outputFormat));
}
return cs;
}
/**
* Obtains the set of output formats supported by the codec
* given a particular input format.
* If no output formats are supported for this input format,
* returns an array of length 0.
* @return array of supported output formats.
*/
/* public AudioFormat[] getOutputFormats(AudioFormat inputFormat) { */
private AudioFormat[] getOutputFormats(AudioFormat inputFormat) {
Vector formats = new Vector();
AudioFormat format;
if ((inputFormat.getSampleSizeInBits() == 16)
&& AudioFormat.Encoding.PCM_SIGNED.equals(inputFormat.getEncoding())) {
format = new AudioFormat(AudioFormat.Encoding.ULAW,
inputFormat.getSampleRate(),
8,
inputFormat.getChannels(),
inputFormat.getChannels(),
inputFormat.getSampleRate(),
false );
formats.addElement(format);
}
if (AudioFormat.Encoding.ULAW.equals(inputFormat.getEncoding())) {
format = new AudioFormat(AudioFormat.Encoding.PCM_SIGNED,
inputFormat.getSampleRate(),
16,
inputFormat.getChannels(),
inputFormat.getChannels()*2,
inputFormat.getSampleRate(),
false );
formats.addElement(format);
format = new AudioFormat(AudioFormat.Encoding.PCM_SIGNED,
inputFormat.getSampleRate(),
16,
inputFormat.getChannels(),
inputFormat.getChannels()*2,
inputFormat.getSampleRate(),
true );
formats.addElement(format);
}
AudioFormat[] formatArray = new AudioFormat[formats.size()];
for (int i = 0; i < formatArray.length; i++) {
formatArray[i] = (AudioFormat)(formats.elementAt(i));
}
return formatArray;
}
class UlawCodecStream extends AudioInputStream {
private static final int tempBufferSize = 64;
private byte tempBuffer [] = null;
/**
* True to encode to u-law, false to decode to linear
*/
boolean encode = false;
AudioFormat encodeFormat;
AudioFormat decodeFormat;
byte tabByte1[] = null;
byte tabByte2[] = null;
int highByte = 0;
int lowByte = 1;
UlawCodecStream(AudioInputStream stream, AudioFormat outputFormat) {
super(stream, outputFormat, AudioSystem.NOT_SPECIFIED);
AudioFormat inputFormat = stream.getFormat();
// throw an IllegalArgumentException if not ok
if (!(isConversionSupported(outputFormat, inputFormat))) {
throw new IllegalArgumentException("Unsupported conversion: " + inputFormat.toString() + " to " + outputFormat.toString());
}
//$$fb 2002-07-18: fix for 4714846: JavaSound ULAW (8-bit) encoder erroneously depends on endian-ness
boolean PCMIsBigEndian;
// determine whether we are encoding or decoding
if (AudioFormat.Encoding.ULAW.equals(inputFormat.getEncoding())) {
encode = false;
encodeFormat = inputFormat;
decodeFormat = outputFormat;
PCMIsBigEndian = outputFormat.isBigEndian();
} else {
encode = true;
encodeFormat = outputFormat;
decodeFormat = inputFormat;
PCMIsBigEndian = inputFormat.isBigEndian();
tempBuffer = new byte[tempBufferSize];
}
// setup tables according to byte order
if (PCMIsBigEndian) {
tabByte1 = ULAW_TABH;
tabByte2 = ULAW_TABL;
highByte = 0;
lowByte = 1;
} else {
tabByte1 = ULAW_TABL;
tabByte2 = ULAW_TABH;
highByte = 1;
lowByte = 0;
}
// set the AudioInputStream length in frames if we know it
if (stream instanceof AudioInputStream) {
frameLength = ((AudioInputStream)stream).getFrameLength();
}
// set framePos to zero
framePos = 0;
frameSize = inputFormat.getFrameSize();
if (frameSize == AudioSystem.NOT_SPECIFIED) {
frameSize = 1;
}
}
/*
* $$jb 2/23/99
* Used to determine segment number in uLaw encoding
*/
private short search(short val, short table[], short size) {
for(short i = 0; i < size; i++) {
if (val <= table[i]) { return i; }
}
return size;
}
/**
* Note that this won't actually read anything; must read in
* two-byte units.
*/
public int read() throws IOException {
byte[] b = new byte[1];
if (read(b, 0, b.length) == 1) {
return b[1] & 0xFF;
}
return -1;
}
public int read(byte[] b) throws IOException {
return read(b, 0, b.length);
}
public int read(byte[] b, int off, int len) throws IOException {
// don't read fractional frames
if( len%frameSize != 0 ) {
len -= (len%frameSize);
}
if (encode) {
short BIAS = 0x84;
short mask;
short seg;
int i;
short sample;
byte enc;
int readCount = 0;
int currentPos = off;
int readLeft = len*2;
int readLen = ( (readLeft>tempBufferSize) ? tempBufferSize : readLeft );
while ((readCount = super.read(tempBuffer,0,readLen))>0) {
for(i = 0; i < readCount; i+=2) {
/* Get the sample from the tempBuffer */
sample = (short)(( (tempBuffer[i + highByte]) << 8) & 0xFF00);
sample |= (short)( (short) (tempBuffer[i + lowByte]) & 0xFF);
/* Get the sign and the magnitude of the value. */
if(sample < 0) {
sample = (short) (BIAS - sample);
mask = 0x7F;
} else {
sample += BIAS;
mask = 0xFF;
}
/* Convert the scaled magnitude to segment number. */
seg = search(sample, seg_end, (short) 8);
/*
* Combine the sign, segment, quantization bits;
* and complement the code word.
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