https://github.com/behdad/harfbuzz/pull/590#issuecomment-340967271

These are CFF fonts and ot functions don’t support CFF glyph names yet.
The next commit will run all tests with ot functions.

Turns out we already have support for “post” table, it just needed to be
activated and put in use.

We might want to tweak this some more.  For now, never skipping over
it is better behavior than always skipping.

Part of https://github.com/behdad/harfbuzz/issues/554

Fixes https://github.com/behdad/harfbuzz/issues/435

Fixes https://github.com/behdad/harfbuzz/issues/509

Apparently a base glyph can also become an attached component of a
ligature if the ligature-forming lookup used IgnoreBase.  This was
being confused with a non-first component of a MultipleSubst and
hence not matched for mark-attachment.  Tweak test to fix.

Fixes https://github.com/behdad/harfbuzz/issues/543

Fixes https://github.com/behdad/harfbuzz/issues/551

New Indic numbers are:

BENGALI: 353725 out of 354188 tests passed. 463 failed (0.130722%)
DEVANAGARI: 707307 out of 707394 tests passed. 87 failed (0.0122987%)
GUJARATI: 366355 out of 366457 tests passed. 102 failed (0.0278341%)
GURMUKHI: 60729 out of 60747 tests passed. 18 failed (0.0296311%)
KANNADA: 951201 out of 951913 tests passed. 712 failed (0.0747968%)
KHMER: 299071 out of 299124 tests passed. 53 failed (0.0177184%)
MALAYALAM: 1048136 out of 1048334 tests passed. 198 failed (0.0188871%)
ORIYA: 42320 out of 42329 tests passed. 9 failed (0.021262%)
SINHALA: 271662 out of 271847 tests passed. 185 failed (0.068053%)
TAMIL: 1091754 out of 1091754 tests passed. 0 failed (0%)
TELUGU: 970555 out of 970573 tests passed. 18 failed (0.00185457%)

Before 71c0a142 GURMUKHI used to be at 15,
because Uniscribe seems to allow this character standalone, but that looks
wrong.

If two marks want to ligate and they belong to different components of the
same ligature glyph, and said ligature glyph is to be ignored according to
mark-filtering rules, then allow.

Example Burmese senquence:

  U+1004,U+103A,U+1039,U+101B,U+103D,U+102D

Test font provided by Norbert Lindenberg.

Fixes https://github.com/behdad/harfbuzz/issues/545

Mark it as matra below to allow the sequence U+0A15, U+0A51, U+0A47.
Oh well...

Fixes https://github.com/behdad/harfbuzz/issues/524

https://github.com/behdad/harfbuzz/issues/538

Fixes https://github.com/behdad/harfbuzz/issues/528
"Kannada JIHVAMULIYA and UPADHMANIYA insert dotted circles"

Fixes https://github.com/behdad/harfbuzz/issues/505

Fixes https://github.com/behdad/harfbuzz/issues/376

Part of https://github.com/behdad/harfbuzz/issues/376
Also see https://github.com/roozbehp/unicode-data/issues/6

Test added, using NotoSansCham built from Noto Phase III sources.

Fixes https://github.com/behdad/harfbuzz/issues/294

Also fixes a bunch of other Indic issues.  Test results after:

BENGALI: 353725 out of 354188 tests passed. 463 failed (0.130722%)
DEVANAGARI: 707307 out of 707394 tests passed. 87 failed (0.0122987%)
GUJARATI: 366355 out of 366457 tests passed. 102 failed (0.0278341%)
GURMUKHI: 60732 out of 60747 tests passed. 15 failed (0.0246926%)
KANNADA: 951201 out of 951913 tests passed. 712 failed (0.0747968%)
KHMER: 299071 out of 299124 tests passed. 53 failed (0.0177184%)
MALAYALAM: 1048136 out of 1048334 tests passed. 198 failed (0.0188871%)
ORIYA: 42320 out of 42329 tests passed. 9 failed (0.021262%)
SINHALA: 271662 out of 271847 tests passed. 185 failed (0.068053%)
TAMIL: 1091754 out of 1091754 tests passed. 0 failed (0%)
TELUGU: 970555 out of 970573 tests passed. 18 failed (0.00185457%)

Before:

BENGALI: 353725 out of 354188 tests passed. 463 failed (0.130722%)
DEVANAGARI: 707307 out of 707394 tests passed. 87 failed (0.0122987%)
GUJARATI: 366349 out of 366457 tests passed. 108 failed (0.0294714%)
GURMUKHI: 60732 out of 60747 tests passed. 15 failed (0.0246926%)
KANNADA: 951190 out of 951913 tests passed. 723 failed (0.0759523%)
KHMER: 299070 out of 299124 tests passed. 54 failed (0.0180527%)
MALAYALAM: 1048136 out of 1048334 tests passed. 198 failed (0.0188871%)
ORIYA: 42320 out of 42329 tests passed. 9 failed (0.021262%)
SINHALA: 271662 out of 271847 tests passed. 185 failed (0.068053%)
TAMIL: 1091753 out of 1091754 tests passed. 1 failed (9.15957e-05%)
TELUGU: 970555 out of 970573 tests passed. 18 failed (0.00185457%)

* Shaping tests for Tibetan vowels

* Test-cases for the Dzongkha contractions with multiple vowel-signs added.

* going to be removed

* Extended contraction-test-cases to all test cases in contractions.txt that actually use multiple-vowels (113 cases)

Hide them like Mongolian Free Variation Selectors instead.

Fixes https://github.com/behdad/harfbuzz/issues/463

This reverts commit b9b005f3.

This introduced invalid access cases. Revert until I fix correctly.

This was broken forever, since days that we did not allow moving
tape backwards. Works now. Reported by Doug Felt.

* Guard against underflow when adjusting length

With the fuzz-testcase in mozilla bug 1295299, we end up with a recursed lookup that removes 3 items, when `match_positions[idx]` is 0, which results in (unsigned) `end` wrapping to a huge value.

Making `end` a signed int is probably the simplest route to a fix.

Fixes https://bugzilla.mozilla.org/show_bug.cgi?id=1295299.

* Add testcase for #421.

* [indic] Add support for Grantha marks that may be used in Tamil to the Indic table.

See https://bugzilla.mozilla.org/show_bug.cgi?id=1331339.

Testcase: U+0BA4,U+0BC6,U+1133c,U+0BAA,U+1133c,U+0BC6,U+1133c

* [indic] Add test for Grantha nukta that is allowed in Tamil by ScriptExtensions.txt

Fixes joined Adlam rendering.

Fixes https://github.com/googlei18n/noto-fonts/issues/828

The numbers for right-to-left scripts are processed also from right to
left, so the order of applying “numr” and “dnom” features should be
reversed in such case.

Fixes https://github.com/behdad/harfbuzz/issues/395

From http://www.babelstone.co.uk/Fonts/Marchen.html

As discovered by libFuzzer / Chromium fuzzing.

Fixes https://bugs.chromium.org/p/chromium/issues/detail?id=659496
CC https://github.com/behdad/harfbuzz/issues/139

Using font from https://github.com/behdad/harfbuzz/issues/300