Base64OutputStream.java

/*
 * SVG Salamander
 * Copyright (c) 2004, Mark McKay
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or 
 * without modification, are permitted provided that the following
 * conditions are met:
 *
 *   - Redistributions of source code must retain the above 
 *     copyright notice, this list of conditions and the following
 *     disclaimer.
 *   - Redistributions in binary form must reproduce the above
 *     copyright notice, this list of conditions and the following
 *     disclaimer in the documentation and/or other materials 
 *     provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE. 
 * 
 * Mark McKay can be contacted at mark@kitfox.com.  Salamander and other
 * projects can be found at http://www.kitfox.com
 */

package com.kitfox.svg.xml;

import java.io.FilterOutputStream;
import java.io.IOException;
import java.io.OutputStream;

/**
 *
 * @author kitfox
 */
public class Base64OutputStream extends FilterOutputStream {
	int buf;
	int numBytes;
	int numChunks;

	public Base64OutputStream(OutputStream out) {
		super(out);
	}

	@Override
	public void flush() throws IOException {
		out.flush();
	}

	@Override
	public void close() throws IOException {
		switch (numBytes) {
		case 1:
			buf <<= 4;
			out.write(getBase64Byte(1));
			out.write(getBase64Byte(0));
			out.write('=');
			out.write('=');
			break;
		case 2:
			buf <<= 2;
			out.write(getBase64Byte(2));
			out.write(getBase64Byte(1));
			out.write(getBase64Byte(0));
			out.write('=');
			break;
		case 3:
			out.write(getBase64Byte(3));
			out.write(getBase64Byte(2));
			out.write(getBase64Byte(1));
			out.write(getBase64Byte(0));
			break;
		default:
			assert false;
		}

		out.close();
	}

	@Override
	public void write(int b) throws IOException {
		buf = (buf << 8) | (0xff & b);
		numBytes++;

		if (numBytes == 3) {
			out.write(getBase64Byte(3));
			out.write(getBase64Byte(2));
			out.write(getBase64Byte(1));
			out.write(getBase64Byte(0));

			numBytes = 0;
			numChunks++;
			if (numChunks == 16) {
				// out.write('\r');
				// out.write('\n');
				numChunks = 0;
			}
		}
	}

	public byte getBase64Byte(int index) {
		return Base64Util.encodeByte((buf >> (index * 6)) & 0x3f);
	}
}