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https://issues.apache.org/jira/browse/PDFBOX-3990?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16238941#comment-16238941
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Andreas Lehmkühler commented on PDFBOX-3990:
--------------------------------------------
bq. Maybe the author, Ben Litchfield, should be contacted to confirm this?
Ben is the founder of PDFBox but no longer active. We, the members of the
Apache PDFBox project, are maintaining the code for about 9 years now, you can
be sure that we know what we are doing.
> 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: 2.0.8
> Environment: Java 1.8
> Reporter: Kristian Jörg
> Assignee: Andreas Lehmkühler
> Priority: Critical
> Fix For: 2.0.9
>
> 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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