/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.pdfbox.filter;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.zip.DataFormatException;
import java.util.zip.DeflaterOutputStream;
import java.util.zip.Inflater;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.pdfbox.cos.COSArray;
import org.apache.pdfbox.cos.COSBase;
import org.apache.pdfbox.cos.COSDictionary;
import org.apache.pdfbox.cos.COSName;
/**
* This is the used for the FlateDecode filter.
*
* @author <a href="mailto:ben@benlitchfield.com">Ben Litchfield</a>
* @author Marcel Kammer
* @version $Revision: 1.12 $
*/
public class FlateFilter implements Filter
{
/**
* Log instance.
*/
private static final Log LOG = LogFactory.getLog(FlateFilter.class);
private static final int BUFFER_SIZE = 16348;
/**
* {@inheritDoc}
*/
public void decode(InputStream compressedData, OutputStream result, COSDictionary options, int filterIndex )
throws IOException
{
COSBase baseObj = options.getDictionaryObject(COSName.DECODE_PARMS, COSName.DP);
COSDictionary dict = null;
if (baseObj instanceof COSDictionary)
{
dict = (COSDictionary) baseObj;
}
else if (baseObj instanceof COSArray)
{
COSArray paramArray = (COSArray) baseObj;
if (filterIndex < paramArray.size())
{
dict = (COSDictionary) paramArray.getObject(filterIndex);
}
}
else if (baseObj != null)
{
throw new IOException("Error: Expected COSArray or COSDictionary and not "
+ baseObj.getClass().getName());
}
int predictor = -1;
if (dict != null)
{
predictor = dict.getInt(COSName.PREDICTOR);
}
try
{
// Decode data using given predictor
if (predictor > 1)
{
int colors = Math.min(dict.getInt(COSName.COLORS, 1), 32);
int bitsPerPixel = dict.getInt(COSName.BITS_PER_COMPONENT, 8);
int columns = dict.getInt(COSName.COLUMNS, 1);
ByteArrayOutputStream baos = new ByteArrayOutputStream();
decompress(compressedData, baos);
ByteArrayInputStream bais = new ByteArrayInputStream(baos.toByteArray());
Predictor.decodePredictor(predictor, colors, bitsPerPixel, columns, bais, result);
result.flush();
baos.reset();
bais.reset();
}
else
{
decompress(compressedData, result);
}
}
catch (DataFormatException exception)
{
// if the stream is corrupt a DataFormatException may occur
LOG.error("FlateFilter: stop reading corrupt stream due to a DataFormatException");
// re-throw the exception, caller has to handle it
IOException io = new IOException();
io.initCause(exception);
throw io;
}
}
// Use Inflater instead of InflateInputStream to avoid an EOFException due to a probably
// missing Z_STREAM_END, see PDFBOX-1232 for details
private void decompress(InputStream in, OutputStream out) throws IOException, DataFormatException
{
byte[] buf = new byte[2048];
int read = in.read(buf);
if(read > 0)
{
Inflater inflater = new Inflater();
inflater.setInput(buf,0,read);
byte[] res = new byte[2048];
while(true)
{
int resRead = inflater.inflate(res);
if(resRead != 0)
{
out.write(res,0,resRead);
continue;
}
if(inflater.finished() || inflater.needsDictionary() || in.available() == 0)
{
break;
}
read = in.read(buf);
inflater.setInput(buf,0,read);
}
}
out.close();
}
/**
* {@inheritDoc}
*/
public void encode(InputStream rawData, OutputStream result, COSDictionary options, int filterIndex )
throws IOException
{
DeflaterOutputStream out = new DeflaterOutputStream(result);
int amountRead = 0;
int mayRead = rawData.available();
if (mayRead > 0)
{
byte[] buffer = new byte[Math.min(mayRead,BUFFER_SIZE)];
while ((amountRead = rawData.read(buffer, 0, Math.min(mayRead,BUFFER_SIZE))) != -1)
{
out.write(buffer, 0, amountRead);
}
}
out.close();
result.flush();
}
}