2022.12.09 15:48 "[Tiff] libtiff v4.5.0 release candidate available", by Even Rouault

2022.12.11 19:07 "Re: [Tiff] libtiff v4.5.0 release candidate available", by Bob Friesenhahn

The unfortunate quadratic performance of IFD looping detection is not something new. I can reproduce it with older libtiff too. We'd probably need the equivalent of std::set<uint64_t> setOfIFDOffsets to have good performance

It seems that it is a pre-existing condition. After fixing a stupid performace anomaly in GM, it is now consuming 69% of the execution time, according to valgrind's cachegrind.

But it is not time to fix that at release candidate stage. The priority would be to avoid the regression of the error message when reading the 65535th IFD. I've CC'ed Su Laus who did work in that area during this dev cycle.

I agree with that.


Bob Friesenhahn
bfriesen@simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer, http://www.GraphicsMagick.org/
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