PSD reading: don't reject padded thumbnails #3677
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When reading PSD file, if reading the thumbnail doesn't pass basic sanity checks, we consider that a hard error reading the file. One check that we do is to make sure that our computation of the byte width of the uncompressed thumbnail (`bpp/8 * width`) matches what the file says the `widthbytes` is. BUT... it seems that it might round up to an even (or maybe 4-multiple?) of columns, presumably for scanline alignment reasons. And so we were considering whole PDF files unreadable if they fell into this case. This PR primaril loosens the test to allow some padding up to a multiple of 4. Fixes 3658
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…n#3677) When reading PSD file, if reading the thumbnail doesn't pass basic sanity checks, we consider that a hard error reading the file. One check that we do is to make sure that our computation of the byte width of the uncompressed thumbnail (`bpp/8 * width`) matches what the file says the `widthbytes` is. BUT... it seems that it might round up to an even (or maybe 4-multiple?) of columns, presumably for scanline alignment reasons. And so we were considering whole PDF files unreadable if they fell into this case. This PR primarily loosens the test to allow some padding up to a multiple of 4. Fixes AcademySoftwareFoundation#3658
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When reading PSD file, if reading the thumbnail doesn't pass basic sanity checks, we consider that a hard error reading the file. One check that we do is to make sure that our computation of the byte width of the uncompressed thumbnail (
bpp/8 * width) matches what the file says thewidthbytesis.BUT... it seems that it might round up to an even (or maybe 4-multiple?) of columns, presumably for scanline alignment reasons. And so we were considering whole PDF files unreadable if they fell into this case.
This PR primaril loosens the test to allow some padding up to a multiple of 4.
Fixes #3658