API change: all fonts created with hb_font_create() now inherit from
(ie have parent) hb_font_get_empty().

It makes the binary smaller AND faster.  Yumm!

Now that we have a buffer-wide scratch flags facility, use it to
optimize away a few passes.

Used to be 100.  If a tabe needs more than one or two edits, it's
probably completely bogus...

Might help with speeding up fuzzing for
https://github.com/behdad/harfbuzz/issues/157

Test passes now.

U+2011 is <noBreak> equivaent of U+2010, so we should do the fallback
for it.  Currently fails.

See discussion here:
https://github.com/behdad/harfbuzz/commit/81ef4f407d9c7bd98cf62cef951dc538b13442eb

There's no way to disable this fallback, but I don't think it would
be needed.  Let's hope for the best!

Fixes https://github.com/behdad/harfbuzz/issues/153

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