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

["Andreas Lehmkühler (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/PDFBOX-3990?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Andreas Lehmkühler reassigned PDFBOX-3990:
------------------------------------------

    Assignee: Andreas Lehmkühler

> 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
>            Assignee: Andreas Lehmkühler
>            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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