package com.streamvantage.BaseUtilities;

import java.io.*;

public class XMLMessage {

	public static final byte EOM = 0x04;
	public static final byte ESC = 0x1b;


	public static class XMLInputStream 
		extends FilterInputStream {
		
		private boolean EOFEncountered = false;
		
		public XMLInputStream (InputStream is) {
			super (is);
		}
		
		public InputStream getUnderlyingStream () {
			return in;
		}
		
		public int read () throws IOException {
			if (EOFEncountered) {
				return -1;
			}
			
			int b = super.read ();
			if (b == EOM) {
				EOFEncountered = true;
				return -1;
			} else if (b == ESC) {
				return super.read ();
			} else {
				return b;
			}
		}
		
		public int read (byte [] b, int off, int len) throws IOException {
			if (b == null) {
			    throw new NullPointerException ();
			} else if ((off < 0) || (off > b.length) || (len < 0) ||
				   ((off + len) > b.length) || ((off + len) < 0)) {
			    throw new IndexOutOfBoundsException ();
			} else if (len == 0) {
				return 0;
			}
			
			int i;
			int c = read ();
			if (c == -1) {
				return -1;
			}
			b [off] = (byte) c;
			
			for (i = 1; i < len; i++) {
				c = read ();
				if (c == -1) {
					return i;
				}
				b [off + i] = (byte) c;
			}
			
			return len;
		}
		
		public void close () throws IOException {
		}
	
	}
	
	public static class XMLOutputStream 
		extends FilterOutputStream {
		
		public XMLOutputStream (OutputStream os) {
			super (os);
		}
		
		public OutputStream getUnderlyingStream () {
			return out;
		}
		
		public void write (int b) throws IOException {
			if (b == EOM) {
				super.write (ESC);
			} else if (b == ESC) {
				super.write (ESC);
			}
			super.write (b);
		}
		
		public void close () throws IOException {
			super.write (EOM);
			super.flush ();
		}
		
	}


}