CCITTFaxDecodeFilter.java

/*
 * 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.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

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 a filter for the CCITTFax Decoder.
 *
 * @author <a href="mailto:ben@benlitchfield.com">Ben Litchfield</a>
 * @author Marcel Kammer
 * @author Paul King
 * @version $Revision: 1.13 $
 */
public class CCITTFaxDecodeFilter implements Filter
{
    /**
     * Log instance.
     */
    private static final Log log = LogFactory.getLog(CCITTFaxDecodeFilter.class);

    /**
     * Constructor.
     */
    public CCITTFaxDecodeFilter()
    {
    }

    /**
     * {@inheritDoc}
     */
    public void decode(InputStream compressedData, OutputStream result, COSDictionary options, int filterIndex) 
    throws IOException
    {
        
        COSBase decodeP = options.getDictionaryObject(COSName.DECODE_PARMS, COSName.DP);
        COSDictionary decodeParms = null;
        if (decodeP instanceof COSDictionary)
        {
            decodeParms = (COSDictionary)decodeP;
        }
        else if (decodeP instanceof COSArray)
        {
            decodeParms =  (COSDictionary)((COSArray)decodeP).get(0);
        }
        int length = options.getInt(COSName.LENGTH, -1);
        byte[] compressed = null;
        if (length != -1) 
        {
            compressed = new byte[length];
            compressedData.read(compressed, 0, length);
        }
        else
        {
            // inline images don't provide the length of the stream so that
            // we have to read until the end of the stream to find out the length
            ByteArrayOutputStream baos = new ByteArrayOutputStream();
            // the streams inline images are stored in are mostly small ones 
            int tempBufferlength = 512;
            byte[] tempBuffer = new byte[tempBufferlength]; 
            int bytesRead = 0;
            while ( (bytesRead = compressedData.read(tempBuffer, 0, tempBufferlength)) != -1) 
            {
                baos.write(tempBuffer, 0, bytesRead);
            }
            compressed = baos.toByteArray();
        }
        int cols = decodeParms.getInt(COSName.COLUMNS, 1728);
        int rows = decodeParms.getInt(COSName.ROWS, 0);
        int height = options.getInt(COSName.HEIGHT, COSName.H, 0); 
        if (rows > 0 && height > 0)
        {
            // ensure that rows doesn't contain implausible data, see PDFBOX-771
            rows = Math.min(rows, height);
        }
        else 
        {
            // at least one of the values has to have a valid value
            rows = Math.max(rows, height);
        }
        int k = decodeParms.getInt(COSName.K, 0);
        int arraySize = (cols + 7) / 8 * rows;
        byte[] decompressed = new byte[arraySize];
        TIFFFaxDecoder faxDecoder = new TIFFFaxDecoder(1, cols, rows);
        // TODO possible options??
        long tiffOptions = 0;
        if (k == 0)
        {
           faxDecoder.decode1D(decompressed, compressed, 0, rows);
        }
        else if (k > 0)
        {
           faxDecoder.decode2D(decompressed, compressed, 0, rows, tiffOptions);
        }
        else if (k < 0)
        {
           faxDecoder.decodeT6(decompressed, compressed, 0, rows, tiffOptions);
        }
        result.write(decompressed);
    }

    /**
     * {@inheritDoc}
     */
    public void encode(InputStream rawData, OutputStream result, COSDictionary options, int filterIndex ) 
        throws IOException
    {
        log.warn("CCITTFaxDecode.encode is not implemented yet, skipping this stream.");
    }
}