ByteArrayBuffer

gistfile1.txt

public class ByteArrayBuffer {
	private byte[] buffer;
	private int len;

	public ByteArrayBuffer() {
		this(4096);
	}

	public ByteArrayBuffer(int capacity) {
		if (capacity < 0) {
			throw new IllegalArgumentException("capacity can not be negative");
		}
		this.buffer = new byte[capacity];
	}

	public void append(byte[] b, int off, int len) {
		if (b == null) {
			return;
		}
		if (off >= 0 && off <= b.length && len >= 0 && off + len >= 0 && off + len <= b.length) {
			if (len != 0) {
				int newLen = this.len + len;
				if (newLen > this.buffer.length) {
					this.expand(newLen);
				}
				System.arraycopy(b, off, this.buffer, this.len, len);
				this.len = newLen;
			}
		} else {
			throw new IndexOutOfBoundsException("off: " + off + " len: " + len + " b.length: " + b.length);
		}

	}

	private void expand(int newLen) {
		byte[] newBuffer = new byte[Math.max(this.buffer.length << 1, newLen)];
		System.arraycopy(this.buffer, 0, newBuffer, 0, this.len);
		this.buffer = newBuffer;
	}

	public byte[] toByteArray() {
		byte[] b = new byte[this.len];
		System.arraycopy(this.buffer, 0, b, 0, this.len);
		return b;
	}
}