FastByteArrayOutputStream.java

package org.overture.codegen.runtime.copying;

import java.io.InputStream;
import java.io.OutputStream;

/**
 * ByteArrayOutputStream implementation that doesn't synchronize methods and doesn't copy the data on toByteArray().
 */
public class FastByteArrayOutputStream extends OutputStream
{
	/**
	 * Buffer and size
	 */
	protected byte[] buf = null;
	protected int size = 0;

	/**
	 * Constructs a stream with buffer capacity size 5K
	 */
	public FastByteArrayOutputStream()
	{
		this(5 * 1024);
	}

	/**
	 * Constructs a stream with the given initial size
	 */
	public FastByteArrayOutputStream(int initSize)
	{
		this.size = 0;
		this.buf = new byte[initSize];
	}

	/**
	 * Ensures that we have a large enough buffer for the given size.
	 */
	private void verifyBufferSize(int sz)
	{
		if (sz > buf.length)
		{
			byte[] old = buf;
			buf = new byte[Math.max(sz, 2 * buf.length)];
			System.arraycopy(old, 0, buf, 0, old.length);
			old = null;
		}
	}

	public int getSize()
	{
		return size;
	}

	/**
	 * Returns the byte array containing the written data. Note that this array will almost always be larger than the
	 * amount of data actually written.
	 */
	public byte[] getByteArray()
	{
		return buf;
	}

	public final void write(byte b[])
	{
		verifyBufferSize(size + b.length);
		System.arraycopy(b, 0, buf, size, b.length);
		size += b.length;
	}

	public final void write(byte b[], int off, int len)
	{
		verifyBufferSize(size + len);
		System.arraycopy(b, off, buf, size, len);
		size += len;
	}

	public final void write(int b)
	{
		verifyBufferSize(size + 1);
		buf[size++] = (byte) b;
	}

	public void reset()
	{
		size = 0;
	}

	/**
	 * Returns a ByteArrayInputStream for reading back the written data
	 */
	public InputStream getInputStream()
	{
		return new FastByteArrayInputStream(buf, size);
	}

}