FastByteArrayInputStream.java

package com.clone;

import java.io.InputStream;

public class FastByteArrayInputStream extends InputStream {
  /**
	 * Our byte buffer
	 */
	protected byte[] buf = null;

	/**
	 * Number of bytes that we can read from the buffer
	 */
	protected int count = 0;

	/**
	 * Number of bytes that have been read from the buffer
	 */
	protected int pos = 0;

	public FastByteArrayInputStream(byte[] buf, int count) {
		this.buf = buf;
		this.count = count;
	}

	public final int available() {
		return count - pos;
	}

	public final int read() {
		return (pos < count) ? (buf[pos++] & 0xff) : -1;
	}

	public final int read(byte[] b, int off, int len) {
		if (pos >= count)
			return -1;

		if ((pos + len) > count)
			len = (count - pos);

		System.arraycopy(buf, pos, b, off, len);
		pos += len;
		return len;
	}

	public final long skip(long n) {
		if ((pos + n) > count)
			n = count - pos;
		if (n < 0)
			return 0;
		pos += n;
		return n;
	}
}

FastByteArrayOutputStream.java

package com.clone;

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

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);
	}

}