[use] Fix reordering

Fixes #1235.

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

@@ -432,7 +432,8 @@ record_pref (const hb_ot_shape_plan_t *plan HB_UNUSED,
 static inline bool
 is_halant (const hb_glyph_info_t &info)
 {
-  return info.use_category() == USE_H && !_hb_glyph_info_ligated (&info);
+  return (info.use_category() == USE_H || info.use_category() == USE_HVM) &&
+	 !_hb_glyph_info_ligated (&info);
 }
 
 static void
@@ -449,19 +450,38 @@ reorder_syllable (hb_buffer_t *buffer, unsigned int start, unsigned int end)
 
   hb_glyph_info_t *info = buffer->info;
 
-#define BASE_FLAGS (FLAG (USE_B) | FLAG (USE_GB))
+#define POST_BASE_FLAGS (FLAG64 (USE_FM) | \
+			 FLAG64 (USE_FAbv) | \
+			 FLAG64 (USE_FBlw) | \
+			 FLAG64 (USE_FPst) | \
+			 FLAG64 (USE_MAbv) | \
+			 FLAG64 (USE_MBlw) | \
+			 FLAG64 (USE_MPst) | \
+			 FLAG64 (USE_MPre) | \
+			 FLAG64 (USE_VAbv) | \
+			 FLAG64 (USE_VBlw) | \
+			 FLAG64 (USE_VPst) | \
+			 FLAG64 (USE_VPre) | \
+			 FLAG64 (USE_VMAbv) | \
+			 FLAG64 (USE_VMBlw) | \
+			 FLAG64 (USE_VMPst) | \
+			 FLAG64 (USE_VMPre))
 
   /* Move things forward. */
   if (info[start].use_category() == USE_R && end - start > 1)
   {
-    /* Got a repha.  Reorder it to after first base, before first halant. */
+    /* Got a repha.  Reorder it towards the end, but before the first post-base
+     * glyph. */
     for (unsigned int i = start + 1; i < end; i++)
-      if ((FLAG_UNSAFE (info[i].use_category()) & (BASE_FLAGS)) || is_halant (info[i]))
+    {
+      bool is_post_base_glyph = (FLAG64_UNSAFE (info[i].use_category()) & POST_BASE_FLAGS) ||
+				is_halant (info[i]);
+      if (is_post_base_glyph || i == end - 1)
       {
-	/* If we hit a halant, move before it; otherwise it's a base: move to it's
+	/* If we hit a post-base glyph, move before it; otherwise move to the
-	 * place, and shift things in between backward. */
+	 * end. Shift things in between backward. */
 
-	if (is_halant (info[i]))
+	if (is_post_base_glyph)
 	  i--;
 
 	buffer->merge_clusters (start, i + 1);
@@ -471,21 +491,19 @@ reorder_syllable (hb_buffer_t *buffer, unsigned int start, unsigned int end)
 
 	break;
       }
+    }
   }
 
   /* Move things back. */
-  unsigned int j = end;
+  unsigned int j = start;
   for (unsigned int i = start; i < end; i++)
   {
     uint32_t flag = FLAG_UNSAFE (info[i].use_category());
-    if ((flag & (BASE_FLAGS)) || is_halant (info[i]))
+    if (is_halant (info[i]))
     {
-      /* If we hit a halant, move after it; otherwise it's a base: move to it's
+      /* If we hit a halant, move after it; otherwise move to the beginning, and
-       * place, and shift things in between backward. */
+       * shift things in between forward. */
-      if (is_halant (info[i]))
+      j = i + 1;
-	j = i + 1;
-      else
-	j = i;
     }
     else if (((flag) & (FLAG (USE_VPre) | FLAG (USE_VMPre))) &&
 	     /* Only move the first component of a MultipleSubst. */

src/hb.hh

@@ -446,6 +446,8 @@ typedef uint64_t hb_vector_size_impl_t;
 #define FLAG(x) (ASSERT_STATIC_EXPR_ZERO ((unsigned int)(x) < 32) + (1U << (unsigned int)(x)))
 #define FLAG_UNSAFE(x) ((unsigned int)(x) < 32 ? (1U << (unsigned int)(x)) : 0)
 #define FLAG_RANGE(x,y) (ASSERT_STATIC_EXPR_ZERO ((x) < (y)) + FLAG(y+1) - FLAG(x))
+#define FLAG64(x) (ASSERT_STATIC_EXPR_ZERO ((unsigned long long)(x) < 64) + (1ULL << (unsigned long long)(x)))
+#define FLAG64_UNSAFE(x) ((unsigned long long)(x) < 64 ? (1ULL << (unsigned long long)(x)) : 0)
 
 
 /* Size signifying variable-sized array */

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

@@ -9,3 +9,6 @@
 ../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]
 ../fonts/dcf774ca21062e7439f98658b18974ea8b956d0c.ttf::U+11328,U+1134D,U+1CF4:[gid1=0+793|gid2=0+0|gid3=0+0]
+../fonts/4afb0e8b9a86bb9bd73a1247de4e33fbe3c1fd93.ttf::U+1C00,U+1C27,U+1C28,U+1C34,U+1C35:[uni1C35=0+500|uni1C34=0+500|uni1C28=0+500|uni1C27=0+500|uni1C00=0+500]
+../fonts/4afb0e8b9a86bb9bd73a1247de4e33fbe3c1fd93.ttf::U+0D4E,U+0D15,U+0D4D,U+0D15,U+0D46:[uni0D15=0+500|uni0D4E=0+500|uni0D4D=0+500|uni0D46=3+500|uni0D15=3+500]
+../fonts/4afb0e8b9a86bb9bd73a1247de4e33fbe3c1fd93.ttf::U+1102D,U+11046,U+11013,U+11046,U+11013,U+11046:[u11013=0+500|u11046_u11013=0+500|u1102D_u11046=0+500|u11046=0+500]