[jira] [Created] (PDFBOX-3990) Rendering will never complete

["Kristian Jörg (JIRA)" <ji...@apache.org>]

Kristian Jörg created PDFBOX-3990:
-------------------------------------

             Summary: Rendering will never complete
                 Key: PDFBOX-3990
                 URL: https://issues.apache.org/jira/browse/PDFBOX-3990
             Project: PDFBox
          Issue Type: Bug
          Components: Rendering
    Affects Versions: 2.0.7
         Environment: Java 1.8
            Reporter: Kristian Jörg
            Priority: Critical
         Attachments: D90296482_20171102.PDF

I have a PDF file that I am attempting to render with:

{code:java}
PDFRenderer renderer = new PDFRenderer(document);
for (int i = 0; i < 2; i++ ) { // the document is two pages, code simplified
    BufferedImage image = renderer.renderImageWithDPI(i, dpi, ImageType.RGB); 
}
{code}
However, the code never returns. When I pause execution (in Eclipse) I see that execution never leaves the decode() method of org.apache.pdfbox.filter.RunLengthDecodeFilter.

The problem is that the inner loop of while (amountToCopy > 0) in bold below is never executed because the stream has come to EOF! That means that the int compressedRead get a negative value and amountToCopy is _*added *_to instead of being subtracted from.
The loop seems to eventually step out of itself, Probably when the integer warps around when reaching it's max (?)
The problem is easy to catch if setting a conditional breakpoint on compressedRead == -1.

I'll include the PDF. The problem arises on page 2.  

{code:java}
    public DecodeResult decode(InputStream encoded, OutputStream decoded,
                                         COSDictionary parameters, int index) throws IOException
    {
        int dupAmount;
        byte[] buffer = new byte[128];
        while ((dupAmount = encoded.read()) != -1 && dupAmount != RUN_LENGTH_EOD)
        {
            if (dupAmount <= 127)
            {
                int amountToCopy = dupAmount + 1;
                int compressedRead;
               * while(amountToCopy > 0)
                {
                    compressedRead = encoded.read(buffer, 0, amountToCopy);
                    decoded.write(buffer, 0, compressedRead);
                    amountToCopy -= compressedRead;
                }*
            }
            else
            {
                int dupByte = encoded.read();
                for (int i = 0; i < 257 - dupAmount; i++)
                {
                    decoded.write(dupByte);
                }
            }
        }
        return new DecodeResult(parameters);
    }
{code}




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