Issue 20295: imghdr add openexr support

Add support for detect openexr file (http://www.openexr.com/)
Based on information provided by :  http://www.openexr.com/ReadingAndWritingImageFiles.pdf

I make some tests, on different kind of exr file, to check, the new function.

New patch with formatting correction and documentation update.

I'm not sure about the place of the versionadded directive in the documentation.

Martin, it would be better if you do the check the way it's done in test_rast: h.startswith(b'\x76\x2f\x31\x01')

Otherwise, you need to check that that h has at least 4 elements (if it doesn't you'll get an IndexError).

You're right, i make the correction, in a new patch.

I make other tests, with official sample files : http://download.savannah.nongnu.org/releases/openexr/openexr-images-1.4.0.tar.gz

Hi, Martin.

Please see issue19990, which tries to add unit tests for imghdr module. It would be nice if you could expand on it with an exr file, for your use case.

Here's an updated patch with a small exr test file.

This seems commit ready.

New changeset 71b9a841119a by R David Murray in branch 'default':
#20295: Teach imghdr to recognize OpenEXR format images.
http://hg.python.org/cpython/rev/71b9a841119a

Thanks, Martin and Claudiu.

stage: commit review -> resolved

messages: + msg220991

messages: + msg208498

messages: + msg208467

versions: + Python 3.5, - Python 3.4