package ants;

public class ByteArray
{
  byte[] buf;
  int offset;
  int len;

  public ByteArray(int len)
  {
    buf = new byte[len];
    offset = 0;
    this.len = len;
  }

  public ByteArray(byte[] buf)
  {
    this.buf = buf;
    this.offset = 0;
    this.len = buf.length;
  }

  public ByteArray(byte[] buf, int offset)
  {
    this(buf, offset, buf.length-offset);
  }

  public ByteArray(byte[] buf, int offset, int len) 
       throws IndexOutOfBoundsException
  {
    if (offset + len > buf.length || offset < 0 || len < 0)
      throw new IndexOutOfBoundsException();
    this.buf = buf;
    this.offset = offset;
    this.len = len;
  }
  
  public ByteArray(ByteArray parent, int offset)
  {
    this(parent, offset, parent.len-offset);
  }

  public ByteArray(ByteArray parent, int offset, int len)
       throws IndexOutOfBoundsException
  {
    if (offset < 0 || offset + len > parent.len || len < 0)
      throw new IndexOutOfBoundsException();
    buf = parent.buf;
    this.offset = parent.offset + offset;
    this.len = len;
  }

  public final int length()
  {
    return len;
  }

  public final byte getByte(int index) throws IndexOutOfBoundsException
  {
    if (index >= len || index < 0) throw new IndexOutOfBoundsException();
    return buf[offset + index];
  }

  public final void setByte(int index, byte val) 
       throws IndexOutOfBoundsException
  {
    if (index >= len || index < 0) throw new IndexOutOfBoundsException();
    buf[offset+index] = val;
  }

  public final void getBytes(int srcBegin, byte[] dst, int dstBegin, 
			     int length)
  {
    System.arraycopy(buf, offset + srcBegin, dst, dstBegin, length);
  }

  public final void setBytes(int dstBegin, byte[] src, int srcBegin,
			     int length)
  {
    System.arraycopy(src, srcBegin, buf, offset + dstBegin, length);
  }

  public final void setBytes(int dstBegin, ByteArray src, int srcBegin,
			     int length)
  {
    System.arraycopy(src.buf, src.offset + srcBegin, buf, offset + dstBegin, 
		     length);
  }

  public final void setBytes(int dstBegin, String src, int srcBegin,
			     int length)
  {
    src.getBytes(srcBegin, srcBegin + length, buf, offset + dstBegin);
  }

  public final String getString(int hibyte, int offset, int count)
  {
    return new String(buf, hibyte, this.offset + offset, count);
  }

  public final byte[] toBytes()
  {
    if (offset == 0 && len == buf.length)
      return buf;
    else 
      {
	byte[] newbuf = new byte[len];
	System.arraycopy(buf, offset, newbuf, 0, len);
	this.buf = newbuf;
	this.offset = 0;
	return buf;
      }
  }
}