Do NOT ignore Mongolian Free Variation Selectors during matching
Fixes https://github.com/behdad/harfbuzz/issues/234
diff --git a/src/hb-ot-layout-private.hh b/src/hb-ot-layout-private.hh
index 22faa48..778b2c4 100644
--- a/src/hb-ot-layout-private.hh
+++ b/src/hb-ot-layout-private.hh
@@ -218,7 +218,8 @@
* - General_Category: 5 bits.
* - A bit each for:
* * Is it Default_Ignorable(); we have a modified Default_Ignorable().
- * * Two free bits right now.
+ * * Whether it's one of the three Mongolian Free Variation Selectors.
+ * * One free bit right now.
*
* The high-byte has different meanings, switched by the Gen-Cat:
* - For Mn,Mc,Me: the modified Combining_Class.
@@ -230,6 +231,7 @@
enum hb_unicode_props_flags_t {
UPROPS_MASK_GEN_CAT = 0x001Fu,
UPROPS_MASK_IGNORABLE = 0x0020u,
+ UPROPS_MASK_FVS = 0x0040u, /* MONGOLIAN FREE VARIATION SELECTOR 1..3 */
/* If GEN_CAT=FORMAT, top byte masks: */
UPROPS_MASK_Cf_ZWJ = 0x0100u,
@@ -254,6 +256,15 @@
props |= UPROPS_MASK_IGNORABLE;
if (u == 0x200Cu) props |= UPROPS_MASK_Cf_ZWNJ;
if (u == 0x200Du) props |= UPROPS_MASK_Cf_ZWJ;
+ /* Mongolian Free Variation Selectors need to be remembered
+ * because although we need to hide them like default-ignorables,
+ * they need to non-ignorable during shaping. This is similar to
+ * what we do for joiners in Indic-like shapers, but since the
+ * FVSes are GC=Mn, we have use a separate bit to remember them.
+ * Fixes:
+ * https://github.com/behdad/harfbuzz/issues/234
+ */
+ if (unlikely (hb_in_range (u, 0x180Bu, 0x180Du))) props |= UPROPS_MASK_FVS;
}
else if (unlikely (HB_UNICODE_GENERAL_CATEGORY_IS_NON_ENCLOSING_MARK_OR_MODIFIER_SYMBOL (gen_cat)))
{
@@ -349,7 +360,15 @@
static inline hb_bool_t
_hb_glyph_info_is_default_ignorable (const hb_glyph_info_t *info)
{
- return (info->unicode_props() & UPROPS_MASK_IGNORABLE) && !_hb_glyph_info_ligated (info);
+ return (info->unicode_props() & UPROPS_MASK_IGNORABLE) &&
+ !_hb_glyph_info_ligated (info);
+}
+static inline hb_bool_t
+_hb_glyph_info_is_default_ignorable_and_not_fvs (const hb_glyph_info_t *info)
+{
+ return ((info->unicode_props() & (UPROPS_MASK_IGNORABLE|UPROPS_MASK_FVS))
+ == UPROPS_MASK_IGNORABLE) &&
+ !_hb_glyph_info_ligated (info);
}
static inline bool
