001/*
002 * SVG Salamander
003 * Copyright (c) 2004, Mark McKay
004 * All rights reserved.
005 *
006 * Redistribution and use in source and binary forms, with or 
007 * without modification, are permitted provided that the following
008 * conditions are met:
009 *
010 *   - Redistributions of source code must retain the above 
011 *     copyright notice, this list of conditions and the following
012 *     disclaimer.
013 *   - Redistributions in binary form must reproduce the above
014 *     copyright notice, this list of conditions and the following
015 *     disclaimer in the documentation and/or other materials 
016 *     provided with the distribution.
017 *
018 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
019 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
020 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
021 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
022 * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
023 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
024 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
025 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
026 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
027 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
028 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
029 * OF THE POSSIBILITY OF SUCH DAMAGE. 
030 * 
031 * Mark McKay can be contacted at mark@kitfox.com.  Salamander and other
032 * projects can be found at http://www.kitfox.com
033 *
034 * Created on July 23, 2007
035 */
036
037package com.kitfox.svg.util;
038
039import java.io.FilterOutputStream;
040import java.io.IOException;
041import java.io.OutputStream;
042
043/**
044 *
045 * @author kitfox
046 */
047public class Base64OutputStream extends FilterOutputStream implements Base64Consts
048{
049    int buf;
050    int bitsUsed;
051    int charsPrinted;
052    
053    /** Creates a new instance of Base64OutputSream */
054    public Base64OutputStream(OutputStream out)
055    {
056        super(out);
057    }
058
059    @Override
060    public void close() throws IOException
061    {
062        writeBits();
063        super.close();
064    }
065    
066    @Override
067    public void write(int b) throws IOException
068    {
069        buf = buf << 8 | (b & 0xff);
070        bitsUsed += 8;
071        if (bitsUsed == 24)
072        {
073            writeBits();
074        }
075    }
076
077    private void writeBits() throws IOException
078    {
079        int padSize;
080        //Pad unused bits with 0
081        switch (bitsUsed)
082        {
083            case 8:
084            {
085                bitsUsed = 12;
086                buf <<= 4;
087                padSize = 2;
088                break;
089            }
090            case 16:
091            {
092                bitsUsed = 18;
093                buf <<= 2;
094                padSize = 1;
095                break;
096            }
097            default:
098            {
099                padSize = 0;
100                break;
101            }
102        }
103        
104        if (charsPrinted == 76)
105        {
106            out.write('\r');
107            out.write('\n');
108            charsPrinted = 0;
109        } 
110        
111        for (; bitsUsed > 0; bitsUsed -= 6)
112        {
113            int b = buf >> (bitsUsed - 6) & 0x3f;
114            out.write(BASE64_CHARS.charAt(b));
115        }
116        
117        for (int i = 0; i < padSize; i++)
118        {
119            out.write('=');
120        }
121        
122        charsPrinted += 4;
123    }
124}