/*
WAVOutputStream - writes a WAV file.
see http://www.mediatel.lu/workshop/audio/fileformat for format spec.
*/
import java.io.*;

public class WAVOutputStream extends java.io.FilterOutputStream
{
	private static final int RIFFid = ('R' << 24) | ('I' << 16) + ('F' << 8) + 'F';
	private static final int WAVEid = ('W' << 24) | ('A' << 16) + ('V' << 8) + 'E';
	private static final int fmtid = ('f' << 24) | ('m' << 16) + ('t' << 8) + ' ';
	private static final int dataid = ('d' << 24) | ('a' << 16) + ('t' << 8) + 'a';

	private int numChannels;
	private int sampleDepth;
	private int sampleRate;
	private int numSamples;

	//for intel byte order. YAY!
	private void writeShort(short val) throws IOException
	{
		out.write((int)(val & 0xFF));
		out.write((int)((val >> 8) & 0xFF));
	}

	private void writeInt(int val) throws IOException
	{
		out.write(val & 0xFF);
		out.write((val >> 8) & 0xFF);
		out.write((val >> 16) & 0xFF);
		out.write((val >> 24) & 0xFF);
	}

	//this allows us to write binary data to the stream
	private DataOutputStream DataOut;

	public WAVOutputStream(OutputStream _out, int channels, int rate, int depth, int length) throws IOException, Exception
	{
		super(_out);

		numChannels = channels;
		sampleRate = rate;
		sampleDepth = depth;
		numSamples = length;
		
		DataOut = new DataOutputStream(out);

		//write "RIFF"
		DataOut.writeInt(RIFFid);
		//write chunk size
		writeInt(4 + 4 + 4 + 24 + 4 + 4 + channels * depth * length / 8);
		//read "WAVE"
		DataOut.writeInt(WAVEid);
		//write format chunk
		DataOut.writeInt(fmtid);
		writeInt(16);
		writeShort(1);
		writeShort((short)channels);
		writeInt(rate);
		writeInt(rate * channels * depth / 8);
		writeShort((short) (channels * depth / 8));
		writeShort((short) depth);
		DataOut.writeInt(dataid);
		writeInt(channels * depth * length / 8);
	}

	public void writeSample(byte b[], int start, int length) throws IOException
	{
		out.write(b, start * numChannels, length * numChannels);
	}

	public void writeSample(short b[], int start, int length) throws IOException
	{
		for(int off = 0; off < length; off++)
			for(int channel = 0; channel < numChannels; channel++)
				writeShort(b[channel + (start + off) * numChannels]);
	}

	public void readSample(int b[], int start, int length) throws IOException
	{
		for(int off = 0; off < length; off++)
			for(int channel = 0; channel < numChannels; channel++)
				writeInt(b[channel + (start + off) * numChannels]);
	}
}