Order Chakma split vowels in accordance with NFC

Fixes #1105.

src/gen-use-table.py

@@ -328,6 +328,9 @@ def map_to_use(data):
 		# TODO: https://github.com/harfbuzz/harfbuzz/pull/626
 		if U == 0xA8B4: UISC = Consonant_Medial
 
+		# TODO: https://github.com/harfbuzz/harfbuzz/issues/1105
+		if U == 0x11134: UISC = Gemination_Mark
+
 		values = [k for k,v in items if v(U,UISC,UGC)]
 		assert len(values) == 1, "%s %s %s %s" % (hex(U), UISC, UGC, values)
 		USE = values[0]
@@ -356,6 +359,13 @@ def map_to_use(data):
 		# https://github.com/roozbehp/unicode-data/issues/8
 		if U == 0x0A51: UIPC = Bottom
 
+		# TODO: https://github.com/harfbuzz/harfbuzz/pull/982
+		if UBlock == 'Chakma' and is_VOWEL (U, UISC, UGC):
+			if UIPC == Top:
+				UIPC = Bottom
+			elif UIPC == Bottom:
+				UIPC = Top
+
 		assert (UIPC in [Not_Applicable, Visual_Order_Left] or
 			USE in use_positions), "%s %s %s %s %s" % (hex(U), UIPC, USE, UISC, UGC)
 

src/hb-ot-shape-complex-use-table.cc

@@ -510,8 +510,8 @@ static const USE_TABLE_ELEMENT_TYPE use_table[] = {
 
   /* 11100 */ VMAbv, VMAbv, VMAbv,     B,     B,     B,     B,     B,     B,     B,     B,     B,     B,     B,     B,     B,
   /* 11110 */     B,     B,     B,     B,     B,     B,     B,     B,     B,     B,     B,     B,     B,     B,     B,     B,
-  /* 11120 */     B,     B,     B,     B,     B,     B,     B,  VAbv,  VAbv,  VAbv,  VBlw,  VBlw,  VPre,  VAbv,  VAbv,  VAbv,
-  /* 11130 */  VAbv,  VBlw,  VBlw,     H,  VAbv,     O,     B,     B,     B,     B,     B,     B,     B,     B,     B,     B,
+  /* 11120 */     B,     B,     B,     B,     B,     B,     B,  VBlw,  VBlw,  VBlw,  VAbv,  VAbv,  VPre,  VBlw,  VAbv,  VAbv,
+  /* 11130 */  VBlw,  VAbv,  VAbv,     H, CMAbv,     O,     B,     B,     B,     B,     B,     B,     B,     B,     B,     B,
   /* 11140 */     O,     O,     O,     O,     B,  VPst,  VPst,     O,     O,     O,     O,     O,     O,     O,     O,     O,
 
   /* Mahajani */

src/hb-ot-shape-complex-use.cc

@@ -560,25 +560,6 @@ reorder (const hb_ot_shape_plan_t *plan,
   HB_BUFFER_DEALLOCATE_VAR (buffer, use_category);
 }
 
-static bool
-decompose_use (const hb_ot_shape_normalize_context_t *c,
-                hb_codepoint_t  ab,
-                hb_codepoint_t *a,
-                hb_codepoint_t *b)
-{
-  switch (ab)
-  {
-    /* Chakma:
-     * Special case where the Unicode decomp gives matras in the wrong order
-     * for cluster validation.
-     */
-    case 0x1112Eu : *a = 0x11127u; *b= 0x11131u; return true;
-    case 0x1112Fu : *a = 0x11127u; *b= 0x11132u; return true;
-  }
-
-  return (bool) c->unicode->decompose (ab, a, b);
-}
-
 static bool
 compose_use (const hb_ot_shape_normalize_context_t *c,
 	     hb_codepoint_t  a,
@@ -602,7 +583,7 @@ const hb_ot_complex_shaper_t _hb_ot_complex_shaper_use =
   nullptr, /* preprocess_text */
   nullptr, /* postprocess_glyphs */
   HB_OT_SHAPE_NORMALIZATION_MODE_COMPOSED_DIACRITICS_NO_SHORT_CIRCUIT,
-  decompose_use,
+  nullptr, /* decompose */
   compose_use,
   setup_masks_use,
   nullptr, /* disable_otl */

test/shaping/data/in-house/tests/use.tests

@@ -2,4 +2,9 @@
 ../fonts/4cce528e99f600ed9c25a2b69e32eb94a03b4ae8.ttf::U+1A48,U+1A58,U+1A25,U+1A48,U+1A58,U+1A25,U+1A6E,U+1A63:[uni1A48=0+1212|uni1A25=0+1912|uni1A58=0+0|uni1A48=3+1212|uni1A6E=3+0|uni1A25=3+1912|uni1A58=3+0|uni1A63=3+1212]
 ../fonts/f518eb6f6b5eec2946c9fbbbde44e45d46f5e2ac.ttf::U+1A48,U+1A58,U+1A25,U+1A48,U+1A58,U+1A25,U+1A6E,U+1A63:[uni1A48=0+1212|uni1A25=0+1912|uni1A58=0+0|uni1A48=3+1212|uni1A6E=3+1211|uni1A25=3+1912|uni1A58=3+0|uni1A63=3+1212]
 ../fonts/6ff0fbead4462d9f229167b4e6839eceb8465058.ttf:--font-funcs=ot:U+11103,U+11128:[u11103=0+837|u11128=0+0]
+../fonts/2a670df15b73a5dc75a5cc491bde5ac93c5077dc.ttf::U+11124,U+1112E:[u11124=0+514|u11131=0+0|u11127=0+0]
+../fonts/2a670df15b73a5dc75a5cc491bde5ac93c5077dc.ttf::U+11124,U+11131,U+11127:[u11124=0+514|u11131=0+0|u11127=0+0]
+../fonts/2a670df15b73a5dc75a5cc491bde5ac93c5077dc.ttf::U+11124,U+11127,U+11131:[u11124=0+514|u11127=0+0|uni25CC=0+547|u11131=0+0]
+../fonts/2a670df15b73a5dc75a5cc491bde5ac93c5077dc.ttf::U+11124,U+11134,U+11131:[u11124=0+514|u11134=0+0|u11131=0+0]
+../fonts/2a670df15b73a5dc75a5cc491bde5ac93c5077dc.ttf::U+11124,U+11131,U+11134:[u11124=0+514|u11131=0+0|uni25CC=0+547|u11134=0+0]
 ../fonts/573d3a3177c9a8646e94c8a0d7b224334340946a.ttf:--font-funcs=ft:U+11410,U+11442,U+11411,U+11440,U+11443,U+11410,U+11442,U+11411,U+11441,U+11443:[E_dv.alt=0+275|Ga.icd=0+367|Gha.diag=0@100,0+386|AA_dv.alt=0+208|Candrabindu=0@17,-8+0|E_dv.alt=5+275|Ga.icd=5+367|Gha.diag=5@100,0+386|AU_dv_part.alt=5+213|Candrabindu.sm=5@-52,179+0]