[OpenJDK 2D-Dev] REG : JDK-8160943 : [PIT] new failure of closed/javax/imageio/ReadAllThumbnailsTest.java

Phil Race philip.race at oracle.com
Fri Jul 8 19:07:10 UTC 2016


On 07/08/2016 04:08 AM, Jayathirth D V wrote:
>
> Hi,
>
> In JDK-8152672 <https://bugs.openjdk.java.net/browse/JDK-8152672> we 
> modified skipImage() in JpegImageReader.java and added tighter checks 
> for parsing Jpeg data.
>
> We have to find any marker,0 or EOF after we find "FF" while parsing 
> JPEG data.
>
> But in JDK-8160943 <https://bugs.openjdk.java.net/browse/JDK-8160943> 
> we have gap between APP0 marker and DQT(FF DB) marker which contains 
> data "00 FF".
>
> APP0_End -> 00 FF -> FF DB(DQT)
>
> So after we skip APP0 marker we find two bytes of data which is "FF 
> FF". In the present code we consider this as invalid marker.
>

See https://www.w3.org/Graphics/JPEG/itu-t81.pdf

B.1.1.2 Markers
Markers serve to identify the various structural parts of the compressed 
data formats.
Most markers start marker segments containing a related group of parameters;
some markers stand alone. All markers are assigned two-byte codes: an
X'FF' byte followed by a byte which is not equal to 0 or X'FF' (see 
Table B.1).
Any marker may optionally be preceded by any number of fill bytes,
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
which are bytes assigned code X'FF
^^^^^^^^^^^^^^^^^^^^^^

-phil.

> Because of this JDK-8160943 
> <https://bugs.openjdk.java.net/browse/JDK-8160943> is failing.
>
> Is the length of APP0 marker not valid in the image or we should not 
> consider "FF FF" as invalid maker?
>
> Please let me know your input.
>
> Thanks,
>
> Jay
>

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