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/*
* 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.FilterInputStream;
import java.io.IOException;
import java.io.InputStream;
/**
*
* @author kitfox
*/
public class Base64InputStream extends FilterInputStream
{
int buf; //Cached bytes to read
int bufSize; //Number of bytes waiting to be read from buffer
boolean drain = false; //After set, read no more chunks
public Base64InputStream(InputStream in)
{
super(in);
}
public int read() throws IOException
{
if (drain && bufSize == 0)
{
return -1;
}
if (bufSize == 0)
{
//Read next chunk into 4 byte buffer
int chunk = in.read();
if (chunk == -1)
{
drain = true;
return -1;
}
//get remaining 3 bytes
for (int i = 0; i < 3; ++i)
{
int value = in.read();
if (value == -1)
{
throw new IOException("Early termination of base64 stream");
}
chunk = (chunk << 8) | (value & 0xff);
}
//Check for special termination characters
if ((chunk & 0xffff) == (((byte)'=' << 8) | (byte)'='))
{
bufSize = 1;
drain = true;
}
else if ((chunk & 0xff) == (byte)'=')
{
bufSize = 2;
drain = true;
}
else
{
bufSize = 3;
}
//Fill buffer with decoded characters
for (int i = 0; i < bufSize + 1; ++i)
{
buf = (buf << 6) | Base64Util.decodeByte((chunk >> 24) & 0xff);
chunk <<= 8;
}
}
//Return nth remaing bte & decrement counter
return (buf >> (--bufSize * 8)) & 0xff;
}
}
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