Fail if blob start plus length overflows; or if blob length
is greater than 2GB. It takes a while for fonts to get to that
size. In the mean time, it protects against bugs like this:
http://www.icu-project.org/trac/ticket/11450
Also avoids some weird issues with 32bit vs 64bit systems
as we accept length as unsigned int. As such, a length of
-1 will cause overflow on 32bit machines, but happily
accepted on a 64bit machine. Avoid that.
In Oriya, a ZWJ/ZWNJ might be added before candrabindu to encourage
or stop ligation of the candrabindu. This is clearly specified in
the Unicode section on Oriya. Allow it there. Note that Uniscribe
doesn't allow this.
Micro tests added using Noto Sans Oriya draft.
No changes in numbers. Currently at:
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: 1048147 out of 1048334 tests passed. 187 failed (0.0178378%)
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%)
Otherwise, we might process a lookup thousands of times, with no
benefit. This pathological case was hit by Noto Nastaliq Urdu Draft
in Firefox's code to determine whether space glyph is involved in
any GSUB/GPOS rules. A test page is at http://behdad.org/urdu
See:
https://bugzilla.mozilla.org/show_bug.cgi?id=1090869
Behdad Esfahbod