floatsamplebuffer.java

linux下建立JAVA虚拟机的源码KAFFE

	 */
	public int getByteArrayBufferSize(AudioFormat format) {
		if (!format.getEncoding().equals(AudioFormat.Encoding.PCM_SIGNED) &&
		        !format.getEncoding().equals(AudioFormat.Encoding.PCM_UNSIGNED)) {
			throw new IllegalArgumentException
			("FloatSampleBuffer: only PCM samples are possible.");
		}
		int bytesPerSample=format.getSampleSizeInBits()/8;
		int bytesPerFrame=bytesPerSample*format.getChannels();
		return bytesPerFrame*getSampleCount();
	}

	/**
	 * @return number of bytes copied to buffer
	 * @throws Exception when buffer is too small or <code>format</code> doesn't match
	 */
	public int convertToByteArray(byte[] buffer, int offset, AudioFormat format) {
		int byteCount=getByteArrayBufferSize(format);
		if (offset+byteCount>buffer.length) {
			throw new IllegalArgumentException
			("FloatSampleBuffer.convertToByteArray: buffer too small.");
		}
		boolean signed=format.getEncoding().equals(AudioFormat.Encoding.PCM_SIGNED);
		if (!signed &&
		        !format.getEncoding().equals(AudioFormat.Encoding.PCM_UNSIGNED)) {
			throw new IllegalArgumentException
			("FloatSampleBuffer.convertToByteArray: only PCM samples are allowed.");
		}
		if (format.getSampleRate()!=getSampleRate()) {
			throw new IllegalArgumentException
			("FloatSampleBuffer.convertToByteArray: different samplerates.");
		}
		if (format.getChannels()!=getChannelCount()) {
			throw new IllegalArgumentException
			("FloatSampleBuffer.convertToByteArray: different channel count.");
		}
		int bytesPerSample=format.getSampleSizeInBits()/8;
		int bytesPerFrame=bytesPerSample*format.getChannels();
		int formatType=getFormatType(format.getSampleSizeInBits(),
		                             signed, format.isBigEndian());
		for (int ch=0; ch<format.getChannels(); ch++) {
			convertFloatToByte(getChannel(ch), sampleCount,
			                   buffer, offset,
			                   bytesPerFrame, formatType);
			offset+=bytesPerSample; // next channel
		}
		return getSampleCount()*bytesPerFrame;
	}

	
	/**
	 * Creates a new byte[] buffer and returns it.
	 * Throws an exception when sample rate doesn't match.
	 * @see #convertToByteArray(byte[], int, AudioFormat)
	 */
	public byte[] convertToByteArray(AudioFormat format) {
		// throws exception when sampleRate doesn't match
		// creates a new byte[] buffer and returns it
		byte[] res=new byte[getByteArrayBufferSize(format)];
		convertToByteArray(res, 0, format);
		return res;
	}

	//////////////////////////////// actions /////////////////////////////////

	/**
	 * Resizes this buffer.
	 * <p>If <code>keepOldSamples</code> is true, as much as possible samples are
	 * retained. If the buffer is enlarged, silence is added at the end.
	 * If <code>keepOldSamples</code> is false, existing samples are discarded
	 * and the buffer contains random samples.
	 */
	public void changeSampleCount(int newSampleCount, boolean keepOldSamples) {
		int oldSampleCount=getSampleCount();
		if (oldSampleCount==newSampleCount) {
			return;
		}
		Object[] oldChannels=null;
		if (keepOldSamples) {
			oldChannels=getAllChannels();
		}
		init(getChannelCount(), newSampleCount, getSampleRate());
		if (keepOldSamples) {
			// copy old channels and eventually silence out new samples
			int copyCount=newSampleCount<oldSampleCount?
			              newSampleCount:oldSampleCount;
			for (int ch=0; ch<getChannelCount(); ch++) {
				float[] oldSamples=(float[]) oldChannels[ch];
				float[] newSamples=(float[]) getChannel(ch);
				if (oldSamples!=newSamples) {
					// if this sample array was not object of lazy delete
					System.arraycopy(oldSamples, 0, newSamples, 0, copyCount);
				}
				if (oldSampleCount<newSampleCount) {
					// silence out new samples
					for (int i=oldSampleCount; i<newSampleCount; i++) {
						newSamples[i]=0.0f;
					}
				}
			}
		}
	}

	public void makeSilence() {
		// silence all channels
		if (getChannelCount()>0) {
			makeSilence(0);
			for (int ch=1; ch<getChannelCount(); ch++) {
				copyChannel(0, ch);
			}
		}
	}

	public void makeSilence(int channel) {
		float[] samples=getChannel(0);
		for (int i=0; i<getSampleCount(); i++) {
			samples[i]=0.0f;
		}
	}

	public void addChannel(boolean silent) {
		// creates new, silent channel
		insertChannel(getChannelCount(), silent);
	}

	/**
	 * lazy insert of a (silent) channel at position <code>index</code>.
	 */
	public void insertChannel(int index, boolean silent) {
		insertChannel(index, silent, LAZY_DEFAULT);
	}

	/**
	 * Inserts a channel at position <code>index</code>.
	 * <p>If <code>silent</code> is true, the new channel will be silent. 
	 * Otherwise it will contain random data.
	 * <p>If <code>lazy</code> is true, hidden channels which have at least getSampleCount()
	 * elements will be examined for reusage as inserted channel.<br>
	 * If <code>lazy</code> is false, still hidden channels are reused,
	 * but it is assured that the inserted channel has exactly getSampleCount() elements,
	 * thus not wasting memory.
	 */
	public void insertChannel(int index, boolean silent, boolean lazy) {
		int physSize=channels.size();
		int virtSize=getChannelCount();
		float[] newChannel=null;
		if (physSize>virtSize) {
			// there are hidden channels. Try to use one.
			for (int ch=virtSize; ch<physSize; ch++) {
				float[] thisChannel=(float[]) channels.get(ch);
				if ((lazy && thisChannel.length>=getSampleCount())
				        || (!lazy && thisChannel.length==getSampleCount())) {
					// we found a matching channel. Use it !
					newChannel=thisChannel;
					channels.remove(ch);
					break;
				}
			}
		}
		if (newChannel==null) {
			newChannel=new float[getSampleCount()];
		}
		channels.add(index, newChannel);
		this.channelCount++;
		if (silent) {
			makeSilence(index);
		}
	}

	/** performs a lazy remove of the channel */
	public void removeChannel(int channel) {
		removeChannel(channel, LAZY_DEFAULT);
	}


	/**
	 * Removes a channel.
	 * If lazy is true, the channel is not physically removed, but only hidden.
	 * These hidden channels are reused by subsequent calls to addChannel 
	 * or insertChannel.
	 */
	public void removeChannel(int channel, boolean lazy) {
		if (!lazy) {
			channels.remove(channel);
		} else if (channel<getChannelCount()-1) {
			// if not already, move this channel at the end
			channels.add(channels.remove(channel));
		}
		channelCount--;
	}

	/**
	 * both source and target channel have to exist. targetChannel
	 * will be overwritten
	 */
	public void copyChannel(int sourceChannel, int targetChannel) {
		float[] source=getChannel(sourceChannel);
		float[] target=getChannel(targetChannel);
		System.arraycopy(source, 0, target, 0, getSampleCount());
	}

	/**
	 * Copies data inside all channel. When the 2 regions
	 * overlap, the behavior is not specified.
	 */
	public void copy(int sourceIndex, int destIndex, int length) {
		for (int i=0; i<getChannelCount(); i++) {
			copy(i, sourceIndex, destIndex, length);
		}
	}

	/**
	 * Copies data inside a channel. When the 2 regions
	 * overlap, the behavior is not specified.
	 */
	public void copy(int channel, int sourceIndex, int destIndex, int length) {
		float[] data=getChannel(channel);
		int bufferCount=getSampleCount();
		if (sourceIndex+length>bufferCount || destIndex+length>bufferCount
			|| sourceIndex<0 || destIndex<0 || length<0) {
				throw new IndexOutOfBoundsException("parameters exceed buffer size");
		}
		System.arraycopy(data, sourceIndex, data, destIndex, length);
	}

	/** 
	 * Mix up of 1 channel to n channels.<br>
	 * It copies the first channel to all newly created channels.
	 * @param targetChannelCount the number of channels that this sample buffer
	 *                        will have after expanding. NOT the number of 
	 *                        channels to add !
	 * @exception IllegalArgumentException if this buffer does not have one 
	 *            channel before calling this method.
	 */
	public void expandChannel(int targetChannelCount) {
		// even more sanity...
		if (getChannelCount()!=1) {
			throw new IllegalArgumentException(
			    "FloatSampleBuffer: can only expand channels for mono signals.");
		}
		for (int ch=1; ch<targetChannelCount; ch++) {
			addChannel(false);
			copyChannel(0, ch);
		}
	}

	/** 
	 * Mix down of n channels to one channel.<br>
	 * It uses a simple mixdown: all other channels are added to first channel.<br>
	 * The volume is NOT lowered !
	 * Be aware, this might cause clipping when converting back
	 * to integer samples.
	 */
	public void mixDownChannels() {
		float[] firstChannel=getChannel(0);
		int sampleCount=getSampleCount();
		int channelCount=getChannelCount();
		for (int ch=channelCount-1; ch>0; ch--) {
			float[] thisChannel=getChannel(ch);
			for (int i=0; i<sampleCount; i++) {
				firstChannel[i]+=thisChannel[i];
			}
			removeChannel(ch);
		}
	}
	
	public void setSamplesFromBytes(byte[] srcBuffer, int srcOffset, AudioFormat format, 
	                                int destOffset, int lengthInSamples) {
		int bytesPerSample = (format.getSampleSizeInBits() + 7)/8;
		int bytesPerFrame = bytesPerSample * format.getChannels();
		
		if (srcOffset + (lengthInSamples * bytesPerFrame) > srcBuffer.length) {
			throw new IllegalArgumentException
			("FloatSampleBuffer.setSamplesFromBytes: srcBuffer too small.");
		}
		if (destOffset + lengthInSamples > getSampleCount()) {
			throw new IllegalArgumentException
			("FloatSampleBuffer.setSamplesFromBytes: destBuffer too small.");
		}
		boolean signed = format.getEncoding().equals(AudioFormat.Encoding.PCM_SIGNED);
		boolean unsigned = format.getEncoding().equals(AudioFormat.Encoding.PCM_UNSIGNED);
		if (!signed && !unsigned) {
			throw new IllegalArgumentException
			("FloatSampleBuffer: only PCM samples are possible.");
		}
		int formatType = getFormatType(format.getSampleSizeInBits(),
		                               signed, format.isBigEndian());

		for (int ch = 0; ch < format.getChannels(); ch++) {
			convertByteToFloat(srcBuffer, srcOffset, bytesPerFrame, formatType,
			                   getChannel(ch), destOffset, lengthInSamples);
			srcOffset += bytesPerSample; // next channel
		}
	}

	//////////////////////////////// properties /////////////////////////////////

	public int getChannelCount() {
		return channelCount;
	}

	public int getSampleCount() {
		return sampleCount;
	}

	public float getSampleRate() {
		return sampleRate;
	}

	/**
	 * Sets the sample rate of this buffer.
	 * NOTE: no conversion is done. The samples are only re-interpreted.
	 */
	public void setSampleRate(float sampleRate) {
		if (sampleRate<=0) {
			throw new IllegalArgumentException
			("Invalid samplerate for FloatSampleBuffer.");
		}
		this.sampleRate=sampleRate;
	}

	/**
	 * NOTE: the returned array may be larger than sampleCount. So in any case, 
	 * sampleCount is to be respected.
	 */
	public float[] getChannel(int channel) {
		if (channel<0 || channel>=getChannelCount()) {
			throw new IllegalArgumentException(