This resurrects the space fallback feature, after I disabled
the compatibility decomposition.  Now I can release HarfBuzz
again without breaking Pango!

It also remembers which space character it was, such that later
on we can approximate the width of this particular space
character.  That part is not implemented yet.

We normalize all GC=Zs chars except for U+1680 OGHA SPACE MARK,
which is better left alone.

Ouch!  Fortunately that function was unused.

Unused so far.

Unused right now.

Exactly the same problem that I fixed in
63ef0b41

I rewrote the table checking yesterday in
67f8821f
and introduced the exact same issue again. :(
Good thing we have ongoing fuzzing going now.  Was discovered
immediately by libFuzzer.  Thanks kcc!

https://github.com/behdad/harfbuzz/issues/139#issuecomment-153449473
Fixes https://github.com/behdad/harfbuzz/issues/156

This has the effect that the font data will end up in a memory
section malloc()ed exactly to its size.  This gives us better
valgrind detection of out-of-bounds access.

Previously, the font data was placed in a mmap()ed section or
GString-allocated area, which didn't have proper protections
at the end when running under valgrind.

I tried moving the is_default_ignorable() function to an INTERNAL
function.  That made the binary size grow by 5k AND things got a
tad bit slower!

Slightly faster.  In prep for more changes.

Saves some time.  Also preparing for reusing the ccc byte for other stuff.

...at compile time.

Also route fuzzing-related tests through hb-ot-font, to reduce dependency
on FreeType behavior for badly-broken fonts.  Fixes failing test with
FreeType master.

Fixes https://github.com/behdad/harfbuzz/issues/152

https://bugzilla.mozilla.org/show_bug.cgi?id=1215894

https://bugzilla.mozilla.org/show_bug.cgi?id=1215894

https://bugzilla.mozilla.org/show_bug.cgi?id=1215894

From https://bugzilla.mozilla.org/show_bug.cgi?id=1215894

Fixes https://github.com/behdad/harfbuzz/issues/146

Or I think it should.

Borrowed from https://bugzilla.mozilla.org/show_bug.cgi?id=1215411

Add BUILD.md based on harfbuzz.org docs

[ci] change to docker infrastructure

The default FreeType load flags where changed from FT_LOAD_NO_HINTING
to FT_LOAD_DEFAULT in 2a9627c5.
This is crashing HarfBuzz-enabled FreeType as I suppose it causes
infinite recursion between HB and FT autohinter...

Revert the behavior change.

Fixes https://github.com/behdad/harfbuzz/issues/143

From:
https://github.com/behdad/harfbuzz/issues/139#issuecomment-147616887
https://github.com/behdad/harfbuzz/issues/139#issuecomment-148289957

Discovered by libFuzzer.  Ouch!

https://github.com/behdad/harfbuzz/issues/139#issuecomment-148289957

We probably should implement better system to catch cyclic lookups.
But for now, this speeds up worst case behavior with broken fonts
considerably without compromising legitimate usecases.

https://github.com/behdad/harfbuzz/issues/139#issuecomment-147788447