[HarfBuzz] slooow HarfBuzz

[Werner LEMBERG]

[harfbuzz 1.3.3]

Behdad,


attached you can find a fuzzed font that exhibits very bad behaviour
of `hb_ot_layout_lookup_collect_glyphs': it iterates a few billion
times while looking up data for `mlym', which is certainly invalid
behaviour.

I've run `ftfuzzer' with

  valgrind --tool=callgrind ftfuzzer slow-unit-0030ddf1f5e8ac716938220235fd61b62e7d5848

(which took about 90 minutes on my not so old Notebook); attached is
its output too so that you can view it with `kcachegrind' or something
similar without running it by yourself.

Please fix :-)


    Werner
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