Roll harfbuzz-ng 3b8fd9c48f4bde368bf2d465c148b9743a9216ee

third_party/harfbuzz-ng/src/hb-ot-shape-complex-indic.cc

 /*
- * Copyright © 2011  Google, Inc.
+ * Copyright © 2011,2012  Google, Inc.
  *
  *  This is part of HarfBuzz, a text shaping library.
  *
  * Permission is hereby granted, without written agreement and without
  * license or royalty fees, to use, copy, modify, and distribute this
  * software and its documentation for any purpose, provided that the
  * above copyright notice and the following two paragraphs appear in
  * all copies of this software.
  *
  * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
  * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
  * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
  * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
  * DAMAGE.
  *
  * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
  * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
  * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
  * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
  * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
  *
  * Google Author(s): Behdad Esfahbod
  */
 
-#include "hb-ot-shape-complex-private.hh"
+#include "hb-ot-shape-complex-indic-private.hh"
+#include "hb-ot-shape-private.hh"
 
+static const struct indic_options_t
+{
+  indic_options_t (void)
+  {
+    char *c = getenv ("HB_OT_INDIC_OPTIONS");
+    uniscribe_bug_compatible = c && strstr (c, "uniscribe-bug-compatible");
+  }
 
-
-/* buffer var allocations */
-#define indic_category() complex_var_persistent_u8_0() /* indic_category_t */
-#define indic_position() complex_var_persistent_u8_1() /* indic_matra_category_t */
-
-#define INDIC_TABLE_ELEMENT_TYPE uint8_t
-
-/* Cateories used in the OpenType spec:
- * https://www.microsoft.com/typography/otfntdev/devanot/shaping.aspx
- */
-/* Note: This enum is duplicated in the -machine.rl source file.
- * Not sure how to avoid duplication. */
-enum indic_category_t {
-  OT_X = 0,
-  OT_C,
-  OT_Ra, /* Not explicitly listed in the OT spec, but used in the grammar. */
-  OT_V,
-  OT_N,
-  OT_H,
-  OT_ZWNJ,
-  OT_ZWJ,
-  OT_M,
-  OT_SM,
-  OT_VD,
-  OT_A,
-  OT_NBSP
-};
-
-/* Visual positions in a syllable from left to right. */
-enum indic_position_t {
-  POS_PRE,
-  POS_BASE,
-  POS_ABOVE,
-  POS_BELOW,
-  POS_POST
-};
-
-/* Categories used in IndicSyllabicCategory.txt from UCD */
-/* The assignments are guesswork */
-enum indic_syllabic_category_t {
-  INDIC_SYLLABIC_CATEGORY_OTHER                 = OT_X,
-
-  INDIC_SYLLABIC_CATEGORY_AVAGRAHA              = OT_X,
-  INDIC_SYLLABIC_CATEGORY_BINDU                 = OT_SM,
-  INDIC_SYLLABIC_CATEGORY_CONSONANT             = OT_C,
-  INDIC_SYLLABIC_CATEGORY_CONSONANT_DEAD        = OT_C,
-  INDIC_SYLLABIC_CATEGORY_CONSONANT_FINAL       = OT_C,
-  INDIC_SYLLABIC_CATEGORY_CONSONANT_HEAD_LETTER = OT_C,
-  INDIC_SYLLABIC_CATEGORY_CONSONANT_MEDIAL      = OT_C,
-  INDIC_SYLLABIC_CATEGORY_CONSONANT_PLACEHOLDER = OT_NBSP,
-  INDIC_SYLLABIC_CATEGORY_CONSONANT_SUBJOINED   = OT_C,
-  INDIC_SYLLABIC_CATEGORY_CONSONANT_REPHA       = OT_C,
-  INDIC_SYLLABIC_CATEGORY_MODIFYING_LETTER      = OT_X,
-  INDIC_SYLLABIC_CATEGORY_NUKTA                 = OT_N,
-  INDIC_SYLLABIC_CATEGORY_REGISTER_SHIFTER      = OT_X,
-  INDIC_SYLLABIC_CATEGORY_TONE_LETTER           = OT_X,
-  INDIC_SYLLABIC_CATEGORY_TONE_MARK             = OT_X,
-  INDIC_SYLLABIC_CATEGORY_VIRAMA                = OT_H,
-  INDIC_SYLLABIC_CATEGORY_VISARGA               = OT_SM,
-  INDIC_SYLLABIC_CATEGORY_VOWEL                 = OT_V,
-  INDIC_SYLLABIC_CATEGORY_VOWEL_DEPENDENT       = OT_M,
-  INDIC_SYLLABIC_CATEGORY_VOWEL_INDEPENDENT     = OT_V
-};
-
-/* Categories used in IndicSMatraCategory.txt from UCD */
-enum indic_matra_category_t {
-  INDIC_MATRA_CATEGORY_NOT_APPLICABLE           = POS_BASE,
-
-  INDIC_MATRA_CATEGORY_LEFT                     = POS_PRE,
-  INDIC_MATRA_CATEGORY_TOP                      = POS_ABOVE,
-  INDIC_MATRA_CATEGORY_BOTTOM                   = POS_BELOW,
-  INDIC_MATRA_CATEGORY_RIGHT                    = POS_POST,
-
-  /* We don't really care much about these since we decompose them
-   * in the generic pre-shaping layer.  They will only be used if
-   * the font does not cover the decomposition.  In which case, we
-   * define these as aliases to the place we want the split-matra
-   * glyph to show up.  Quite arbitrary. */
-  INDIC_MATRA_CATEGORY_BOTTOM_AND_RIGHT         = INDIC_MATRA_CATEGORY_BOTTOM,
-  INDIC_MATRA_CATEGORY_LEFT_AND_RIGHT           = INDIC_MATRA_CATEGORY_LEFT,
-  INDIC_MATRA_CATEGORY_TOP_AND_BOTTOM           = INDIC_MATRA_CATEGORY_BOTTOM,
-  INDIC_MATRA_CATEGORY_TOP_AND_BOTTOM_AND_RIGHT = INDIC_MATRA_CATEGORY_BOTTOM,
-  INDIC_MATRA_CATEGORY_TOP_AND_LEFT             = INDIC_MATRA_CATEGORY_LEFT,
-  INDIC_MATRA_CATEGORY_TOP_AND_LEFT_AND_RIGHT   = INDIC_MATRA_CATEGORY_LEFT,
-  INDIC_MATRA_CATEGORY_TOP_AND_RIGHT            = INDIC_MATRA_CATEGORY_RIGHT,
-
-  INDIC_MATRA_CATEGORY_INVISIBLE                = INDIC_MATRA_CATEGORY_NOT_APPLICABLE,
-  INDIC_MATRA_CATEGORY_OVERSTRUCK               = INDIC_MATRA_CATEGORY_NOT_APPLICABLE,
-  INDIC_MATRA_CATEGORY_VISUAL_ORDER_LEFT        = INDIC_MATRA_CATEGORY_NOT_APPLICABLE
-};
-
-/* Note: We use ASSERT_STATIC_EXPR_ZERO() instead of ASSERT_STATIC_EXPR() and the comma operation
- * because gcc fails to optimize the latter and fills the table in at runtime. */
-#define INDIC_COMBINE_CATEGORIES(S,M) \
-  (ASSERT_STATIC_EXPR_ZERO (M == INDIC_MATRA_CATEGORY_NOT_APPLICABLE || (S == INDIC_SYLLABIC_CATEGORY_VIRAMA || S == INDIC_SYLLABIC_CATEGORY_VOWEL_DEPENDENT)) + \
-   ASSERT_STATIC_EXPR_ZERO (S < 16 && M < 16) + \
-   ((M << 4) | S))
-
-#include "hb-ot-shape-complex-indic-table.hh"
-
-/* XXX
- * This is a hack for now.  We should:
- * 1. Move this data into the main Indic table,
- * and/or
- * 2. Probe font lookups to determine consonant positions.
- */
-static const struct consonant_position_t {
-  hb_codepoint_t u;
-  indic_position_t position;
-} consonant_positions[] = {
-  {0x0930, POS_BELOW},
-  {0x09AC, POS_BELOW},
-  {0x09AF, POS_POST},
-  {0x09B0, POS_BELOW},
-  {0x09F0, POS_BELOW},
-  {0x0A2F, POS_POST},
-  {0x0A30, POS_BELOW},
-  {0x0A35, POS_BELOW},
-  {0x0A39, POS_BELOW},
-  {0x0AB0, POS_BELOW},
-  {0x0B24, POS_BELOW},
-  {0x0B28, POS_BELOW},
-  {0x0B2C, POS_BELOW},
-  {0x0B2D, POS_BELOW},
-  {0x0B2E, POS_BELOW},
-  {0x0B2F, POS_POST},
-  {0x0B30, POS_BELOW},
-  {0x0B32, POS_BELOW},
-  {0x0B33, POS_BELOW},
-  {0x0B5F, POS_POST},
-  {0x0B71, POS_BELOW},
-  {0x0C15, POS_BELOW},
-  {0x0C16, POS_BELOW},
-  {0x0C17, POS_BELOW},
-  {0x0C18, POS_BELOW},
-  {0x0C19, POS_BELOW},
-  {0x0C1A, POS_BELOW},
-  {0x0C1B, POS_BELOW},
-  {0x0C1C, POS_BELOW},
-  {0x0C1D, POS_BELOW},
-  {0x0C1E, POS_BELOW},
-  {0x0C1F, POS_BELOW},
-  {0x0C20, POS_BELOW},
-  {0x0C21, POS_BELOW},
-  {0x0C22, POS_BELOW},
-  {0x0C23, POS_BELOW},
-  {0x0C24, POS_BELOW},
-  {0x0C25, POS_BELOW},
-  {0x0C26, POS_BELOW},
-  {0x0C27, POS_BELOW},
-  {0x0C28, POS_BELOW},
-  {0x0C2A, POS_BELOW},
-  {0x0C2B, POS_BELOW},
-  {0x0C2C, POS_BELOW},
-  {0x0C2D, POS_BELOW},
-  {0x0C2E, POS_BELOW},
-  {0x0C2F, POS_BELOW},
-  {0x0C30, POS_BELOW},
-  {0x0C32, POS_BELOW},
-  {0x0C33, POS_BELOW},
-  {0x0C35, POS_BELOW},
-  {0x0C36, POS_BELOW},
-  {0x0C37, POS_BELOW},
-  {0x0C38, POS_BELOW},
-  {0x0C39, POS_BELOW},
-  {0x0C95, POS_BELOW},
-  {0x0C96, POS_BELOW},
-  {0x0C97, POS_BELOW},
-  {0x0C98, POS_BELOW},
-  {0x0C99, POS_BELOW},
-  {0x0C9A, POS_BELOW},
-  {0x0C9B, POS_BELOW},
-  {0x0C9C, POS_BELOW},
-  {0x0C9D, POS_BELOW},
-  {0x0C9E, POS_BELOW},
-  {0x0C9F, POS_BELOW},
-  {0x0CA0, POS_BELOW},
-  {0x0CA1, POS_BELOW},
-  {0x0CA2, POS_BELOW},
-  {0x0CA3, POS_BELOW},
-  {0x0CA4, POS_BELOW},
-  {0x0CA5, POS_BELOW},
-  {0x0CA6, POS_BELOW},
-  {0x0CA7, POS_BELOW},
-  {0x0CA8, POS_BELOW},
-  {0x0CAA, POS_BELOW},
-  {0x0CAB, POS_BELOW},
-  {0x0CAC, POS_BELOW},
-  {0x0CAD, POS_BELOW},
-  {0x0CAE, POS_BELOW},
-  {0x0CAF, POS_BELOW},
-  {0x0CB0, POS_BELOW},
-  {0x0CB2, POS_BELOW},
-  {0x0CB3, POS_BELOW},
-  {0x0CB5, POS_BELOW},
-  {0x0CB6, POS_BELOW},
-  {0x0CB7, POS_BELOW},
-  {0x0CB8, POS_BELOW},
-  {0x0CB9, POS_BELOW},
-  {0x0CDE, POS_BELOW},
-  {0x0D2F, POS_POST},
-  {0x0D30, POS_POST},
-  {0x0D32, POS_BELOW},
-  {0x0D35, POS_POST},
-};
-
-/* XXX
- * This is a hack for now.  We should move this data into the main Indic table.
- */
-static const hb_codepoint_t ra_chars[] = {
-  0x0930, /* Devanagari */
-  0x09B0, /* Bengali */
-  0x09F0, /* Bengali */
-//0x09F1, /* Bengali */
-//0x0A30, /* Gurmukhi */
-  0x0AB0, /* Gujarati */
-  0x0B30, /* Oriya */
-//0x0BB0, /* Tamil */
-//0x0C30, /* Telugu */
-  0x0CB0, /* Kannada */
-//0x0D30, /* Malayalam */
-};
+  bool uniscribe_bug_compatible;
+} options;
 
 static int
 compare_codepoint (const void *pa, const void *pb)
 {
   hb_codepoint_t a = * (hb_codepoint_t *) pa;
   hb_codepoint_t b = * (hb_codepoint_t *) pb;
 
   return a < b ? -1 : a == b ? 0 : +1;
 }
 
 static indic_position_t
 consonant_position (hb_codepoint_t u)
 {
   consonant_position_t *record;
 
   record = (consonant_position_t *) bsearch (&u, consonant_positions,
                                              ARRAY_LENGTH (consonant_positions),
                                              sizeof (consonant_positions[0]),
                                              compare_codepoint);
 
-  return record ? record->position : POS_BASE;
+  return record ? record->position : POS_BASE_C;
 }
 
 static bool
 is_ra (hb_codepoint_t u)
 {
   return !!bsearch (&u, ra_chars,
                     ARRAY_LENGTH (ra_chars),
                     sizeof (ra_chars[0]),
                     compare_codepoint);
 }
 
 static bool
 is_joiner (const hb_glyph_info_t &info)
 {
   return !!(FLAG (info.indic_category()) & (FLAG (OT_ZWJ) | FLAG (OT_ZWNJ)));
 }
 
 static bool
 is_consonant (const hb_glyph_info_t &info)
 {
-  return !!(FLAG (info.indic_category()) & (FLAG (OT_C) | FLAG (OT_Ra)));
+  /* Note:
+   *
+   * We treat Vowels and placeholders as if they were consonants.  This is safe because Vowels
+   * cannot happen in a consonant syllable.  The plus side however is, we can call the
+   * consonant syllable logic from the vowel syllable function and get it all right! */
+  return !!(FLAG (info.indic_category()) & (FLAG (OT_C) | FLAG (OT_Ra) | FLAG (OT_V) | FLAG (OT_NBSP) | FLAG (OT_DOTTEDCIRCLE)));
 }
 
-static const struct {
+struct feature_list_t {
   hb_tag_t tag;
   hb_bool_t is_global;
-} indic_basic_features[] =
+};
+
+static const feature_list_t
+indic_basic_features[] =
 {
   {HB_TAG('n','u','k','t'), true},
   {HB_TAG('a','k','h','n'), false},
   {HB_TAG('r','p','h','f'), false},
-  {HB_TAG('r','k','r','f'), false},
+  {HB_TAG('r','k','r','f'), true},
   {HB_TAG('p','r','e','f'), false},
   {HB_TAG('b','l','w','f'), false},
   {HB_TAG('h','a','l','f'), false},
-  {HB_TAG('v','a','t','u'), true},
   {HB_TAG('p','s','t','f'), false},
   {HB_TAG('c','j','c','t'), false},
+  {HB_TAG('v','a','t','u'), true},
 };
 
 /* Same order as the indic_basic_features array */
 enum {
   _NUKT,
   AKHN,
   RPHF,
-  RKRF,
+  _RKRF,
   PREF,
   BLWF,
   HALF,
-  _VATU,
   PSTF,
-  CJCT
+  CJCT,
+  VATU
 };
 
-static const hb_tag_t indic_other_features[] =
+static const feature_list_t
+indic_other_features[] =
 {
-  HB_TAG('p','r','e','s'),
-  HB_TAG('a','b','v','s'),
-  HB_TAG('b','l','w','s'),
-  HB_TAG('p','s','t','s'),
-  HB_TAG('h','a','l','n'),
+  {HB_TAG('i','n','i','t'), false},
+  {HB_TAG('p','r','e','s'), true},
+  {HB_TAG('a','b','v','s'), true},
+  {HB_TAG('b','l','w','s'), true},
+  {HB_TAG('p','s','t','s'), true},
+  {HB_TAG('h','a','l','n'), true},
 
-  HB_TAG('d','i','s','t'),
-  HB_TAG('a','b','v','m'),
-  HB_TAG('b','l','w','m'),
+  {HB_TAG('d','i','s','t'), true},
+  {HB_TAG('a','b','v','m'), true},
+  {HB_TAG('b','l','w','m'), true},
+};
+
+/* Same order as the indic_other_features array */
+enum {
+  INIT
 };
 
 
 static void
 initial_reordering (const hb_ot_map_t *map,
                     hb_face_t *face,
                     hb_buffer_t *buffer,
                     void *user_data HB_UNUSED);
 static void
 final_reordering (const hb_ot_map_t *map,
                   hb_face_t *face,
                   hb_buffer_t *buffer,
                   void *user_data HB_UNUSED);
 
 void
-_hb_ot_shape_complex_collect_features_indic (hb_ot_map_builder_t *map, const hb_segment_properties_t  *props)
+_hb_ot_shape_complex_collect_features_indic (hb_ot_map_builder_t *map,
+                                             const hb_segment_properties_t *props HB_UNUSED)
 {
   map->add_bool_feature (HB_TAG('l','o','c','l'));
   /* The Indic specs do not require ccmp, but we apply it here since if
    * there is a use of it, it's typically at the beginning. */
   map->add_bool_feature (HB_TAG('c','c','m','p'));
 
   map->add_gsub_pause (initial_reordering, NULL);
 
-  for (unsigned int i = 0; i < ARRAY_LENGTH (indic_basic_features); i++)
+  for (unsigned int i = 0; i < ARRAY_LENGTH (indic_basic_features); i++) {
     map->add_bool_feature (indic_basic_features[i].tag, indic_basic_features[i].is_global);
+    map->add_gsub_pause (NULL, NULL);
+  }
 
   map->add_gsub_pause (final_reordering, NULL);
 
-  for (unsigned int i = 0; i < ARRAY_LENGTH (indic_other_features); i++)
-    map->add_bool_feature (indic_other_features[i], true);
+  for (unsigned int i = 0; i < ARRAY_LENGTH (indic_other_features); i++) {
+    map->add_bool_feature (indic_other_features[i].tag, indic_other_features[i].is_global);
+    map->add_gsub_pause (NULL, NULL);
+  }
 }
 
 
-bool
-_hb_ot_shape_complex_prefer_decomposed_indic (void)
+hb_ot_shape_normalization_mode_t
+_hb_ot_shape_complex_normalization_preference_indic (void)
 {
   /* We want split matras decomposed by the common shaping logic. */
-  return TRUE;
+  return HB_OT_SHAPE_NORMALIZATION_MODE_DECOMPOSED;
 }
 
 
 void
-_hb_ot_shape_complex_setup_masks_indic (hb_ot_map_t *map, hb_buffer_t *buffer)
+_hb_ot_shape_complex_setup_masks_indic (hb_ot_map_t *map HB_UNUSED,
+                                        hb_buffer_t *buffer,
+                                        hb_font_t *font HB_UNUSED)
 {
   HB_BUFFER_ALLOCATE_VAR (buffer, indic_category);
   HB_BUFFER_ALLOCATE_VAR (buffer, indic_position);
 
   /* We cannot setup masks here.  We save information about characters
    * and setup masks later on in a pause-callback. */
 
   unsigned int count = buffer->len;
   for (unsigned int i = 0; i < count; i++)
   {
-    unsigned int type = get_indic_categories (buffer->info[i].codepoint);
+    hb_glyph_info_t &info = buffer->info[i];
+    unsigned int type = get_indic_categories (info.codepoint);
 
-    buffer->info[i].indic_category() = type & 0x0F;
-    buffer->info[i].indic_position() = type >> 4;
+    info.indic_category() = type & 0x0F;
+    info.indic_position() = type >> 4;
 
-    if (buffer->info[i].indic_category() == OT_C) {
-      buffer->info[i].indic_position() = consonant_position (buffer->info[i].codepoint);
-      if (is_ra (buffer->info[i].codepoint))
-        buffer->info[i].indic_category() = OT_Ra;
-    } else if (buffer->info[i].codepoint == 0x200C)
-      buffer->info[i].indic_category() = OT_ZWNJ;
-    else if (buffer->info[i].codepoint == 0x200D)
-      buffer->info[i].indic_category() = OT_ZWJ;
+    /* The spec says U+0952 is OT_A.  However, testing shows that Uniscribe
+     * treats U+0951..U+0952 all as OT_VD.
+     * TESTS:
+     * U+092E,U+0947,U+0952
+     * U+092E,U+0952,U+0947
+     * U+092E,U+0947,U+0951
+     * U+092E,U+0951,U+0947
+     * */
+    if (unlikely (hb_in_range<hb_codepoint_t> (info.codepoint, 0x0951, 0x0954)))
+      info.indic_category() = OT_VD;
+
+    if (info.indic_category() == OT_C) {
+      info.indic_position() = consonant_position (info.codepoint);
+      if (is_ra (info.codepoint))
+        info.indic_category() = OT_Ra;
+    } else if (info.indic_category() == OT_SM ||
+               info.indic_category() == OT_VD) {
+      info.indic_position() = POS_SMVD;
+    } else if (unlikely (info.codepoint == 0x200C))
+      info.indic_category() = OT_ZWNJ;
+    else if (unlikely (info.codepoint == 0x200D))
+      info.indic_category() = OT_ZWJ;
+    else if (unlikely (info.codepoint == 0x25CC))
+      info.indic_category() = OT_DOTTEDCIRCLE;
   }
 }
 
 static int
 compare_indic_order (const hb_glyph_info_t *pa, const hb_glyph_info_t *pb)
 {
   int a = pa->indic_position();
   int b = pb->indic_position();
 
   return a < b ? -1 : a == b ? 0 : +1;
 }
 
+/* Rules from:
+ * https://www.microsoft.com/typography/otfntdev/devanot/shaping.aspx */
+
 static void
-found_consonant_syllable (const hb_ot_map_t *map, hb_buffer_t *buffer, hb_mask_t *mask_array,
-                          unsigned int start, unsigned int end)
+initial_reordering_consonant_syllable (const hb_ot_map_t *map, hb_buffer_t *buffer, hb_mask_t *mask_array,
+                                       unsigned int start, unsigned int end)
 {
-  unsigned int i;
   hb_glyph_info_t *info = buffer->info;
 
-  /* Comments from:
-   * https://www.microsoft.com/typography/otfntdev/devanot/shaping.aspx */
 
   /* 1. Find base consonant:
    *
    * The shaping engine finds the base consonant of the syllable, using the
    * following algorithm: starting from the end of the syllable, move backwards
    * until a consonant is found that does not have a below-base or post-base
    * form (post-base forms have to follow below-base forms), or that is not a
    * pre-base reordering Ra, or arrive at the first consonant. The consonant
    * stopped at will be the base.
    *
    *   o If the syllable starts with Ra + Halant (in a script that has Reph)
    *     and has more than one consonant, Ra is excluded from candidates for
    *     base consonants.
    */
 
   unsigned int base = end;
+  bool has_reph = false;
 
-  /* -> starting from the end of the syllable, move backwards */
-  i = end;
-  unsigned int limit = start;
-  if (info[start].indic_category() == OT_Ra && start + 2 <= end) {
-    limit += 2;
-    base = start;
-  };
-  do {
-    i--;
-    /* -> until a consonant is found */
-    if (is_consonant (info[i]))
+  {
+    /* -> If the syllable starts with Ra + Halant (in a script that has Reph)
+     *    and has more than one consonant, Ra is excluded from candidates for
+     *    base consonants. */
+    unsigned int limit = start;
+    if (mask_array[RPHF] &&
+        start + 3 <= end &&
+        info[start].indic_category() == OT_Ra &&
+        info[start + 1].indic_category() == OT_H &&
+        !is_joiner (info[start + 2]))
     {
-      /* -> that does not have a below-base or post-base form
-       * (post-base forms have to follow below-base forms), */
-      if (info[i].indic_position() != POS_BELOW &&
-          info[i].indic_position() != POS_POST)
+      limit += 2;
+      base = start;
+      has_reph = true;
+    };
+
+    /* -> starting from the end of the syllable, move backwards */
+    unsigned int i = end;
+    do {
+      i--;
+      /* -> until a consonant is found */
+      if (is_consonant (info[i]))
       {
-        base = i;
-        break;
+        /* -> that does not have a below-base or post-base form
+         * (post-base forms have to follow below-base forms), */
+        if (info[i].indic_position() != POS_BELOW_C &&
+            info[i].indic_position() != POS_POST_C)
+        {
+          base = i;
+          break;
+        }
+
+        /* -> or that is not a pre-base reordering Ra,
+         *
+         * TODO
+         */
+
+        /* -> or arrive at the first consonant. The consonant stopped at will
+         * be the base. */
+        base = i;
       }
+      else
+        if (is_joiner (info[i]))
+          break;
+    } while (i > limit);
+    if (base < start)
+      base = start; /* Just in case... */
 
-      /* -> or that is not a pre-base reordering Ra,
-       *
-       * TODO
-       */
 
-      /* ->  o If the syllable starts with Ra + Halant (in a script that has Reph)
-       *       and has more than one consonant, Ra is excluded from candidates for
-       *       base consonants.
-       *
-       * IMPLEMENTATION NOTES:
-       *
-       * We do this by adjusting limit accordingly before entering the loop.
-       */
-
-      /* -> or arrive at the first consonant. The consonant stopped at will
-       * be the base. */
-      base = i;
+    /* -> If the syllable starts with Ra + Halant (in a script that has Reph)
+     *    and has more than one consonant, Ra is excluded from candidates for
+     *    base consonants. */
+    if (has_reph && base == start) {
+      /* Have no other consonant, so Reph is not formed and Ra becomes base. */
+      has_reph = false;
     }
-    else
-      if (is_joiner (info[i]))
-        break;
-  } while (i > limit);
-  if (base < start)
-    base = start; /* Just in case... */
+  }
 
 
   /* 2. Decompose and reorder Matras:
    *
    * Each matra and any syllable modifier sign in the cluster are moved to the
    * appropriate position relative to the consonant(s) in the cluster. The
    * shaping engine decomposes two- or three-part matras into their constituent
    * parts before any repositioning. Matra characters are classified by which
    * consonant in a conjunct they have affinity for and are reordered to the
    * following positions:
@@ skipping 16 matching lines @@
    * if necessary, so that the nukta is first.
    *
    * IMPLEMENTATION NOTES:
    *
    * We don't need to do this: the normalize() routine already did this for us.
    */
 
 
   /* Reorder characters */
 
-  for (i = start; i < base; i++)
-    info[i].indic_position() = POS_PRE;
-  info[base].indic_position() = POS_BASE;
-
+  for (unsigned int i = start; i < base; i++)
+    info[i].indic_position() = POS_PRE_C;
+  info[base].indic_position() = POS_BASE_C;
 
   /* Handle beginning Ra */
-  if (start + 3 <= end &&
-      info[start].indic_category() == OT_Ra &&
-      info[start + 1].indic_category() == OT_H &&
-      !is_joiner (info[start + 2]))
-   {
-    info[start].indic_position() = POS_POST;
-    info[start].mask = mask_array[RPHF];
-   }
+  if (has_reph)
+    info[start].indic_position() = POS_RA_TO_BECOME_REPH;
 
   /* For old-style Indic script tags, move the first post-base Halant after
    * last consonant. */
   if ((map->get_chosen_script (0) & 0x000000FF) != '2') {
     /* We should only do this for Indic scripts which have a version two I guess. */
-    for (i = base + 1; i < end; i++)
+    for (unsigned int i = base + 1; i < end; i++)
       if (info[i].indic_category() == OT_H) {
         unsigned int j;
         for (j = end - 1; j > i; j--)
-          if ((FLAG (info[j].indic_category()) & (FLAG (OT_C) | FLAG (OT_Ra))))
+          if (is_consonant (info[j]))
             break;
         if (j > i) {
           /* Move Halant to after last consonant. */
           hb_glyph_info_t t = info[i];
           memmove (&info[i], &info[i + 1], (j - i) * sizeof (info[0]));
           info[j] = t;
         }
         break;
       }
   }
 
   /* Attach ZWJ, ZWNJ, nukta, and halant to previous char to move with them. */
-  for (i = start + 1; i < end; i++)
-    if ((FLAG (info[i].indic_category()) &
-         (FLAG (OT_ZWNJ) | FLAG (OT_ZWJ) | FLAG (OT_N) | FLAG (OT_H))))
-      info[i].indic_position() = info[i - 1].indic_position();
+  if (!options.uniscribe_bug_compatible)
+  {
+    /* Please update the Uniscribe branch when touching this! */
+    for (unsigned int i = start + 1; i < end; i++)
+      if ((FLAG (info[i].indic_category()) & (FLAG (OT_ZWNJ) | FLAG (OT_ZWJ) | FLAG (OT_N) | FLAG (OT_H))))
+        info[i].indic_position() = info[i - 1].indic_position();
+  } else {
+    /*
+     * Uniscribe doesn't move the Halant with Left Matra.
+     * TEST: U+092B,U+093F,U+094DE
+     */
+    /* Please update the non-Uniscribe branch when touching this! */
+    for (unsigned int i = start + 1; i < end; i++)
+      if ((FLAG (info[i].indic_category()) & (FLAG (OT_ZWNJ) | FLAG (OT_ZWJ) | FLAG (OT_N) | FLAG (OT_H)))) {
+        info[i].indic_position() = info[i - 1].indic_position();
+        if (info[i].indic_category() == OT_H && info[i].indic_position() == POS_PRE_M)
+          for (unsigned int j = i; j > start; j--)
+            if (info[j - 1].indic_position() != POS_PRE_M) {
+              info[i].indic_position() = info[j - 1].indic_position();
+              break;
+            }
+      }
+  }
 
   /* We do bubble-sort, skip malicious clusters attempts */
-  if (end - start > 20)
-    return;
-
-  /* Sit tight, rock 'n roll! */
-  hb_bubble_sort (info + start, end - start, compare_indic_order);
+  if (end - start < 64)
+  {
+    /* Sit tight, rock 'n roll! */
+    hb_bubble_sort (info + start, end - start, compare_indic_order);
+    /* Find base again */
+    base = end;
+    for (unsigned int i = start; i < end; i++)
+      if (info[i].indic_position() == POS_BASE_C) {
+        base = i;
+        break;
+      }
+  }
 
   /* Setup masks now */
 
   {
     hb_mask_t mask;
 
+    /* Reph */
+    for (unsigned int i = start; i < end && info[i].indic_position() == POS_RA_TO_BECOME_REPH; i++)
+      info[i].mask |= mask_array[RPHF];
+
     /* Pre-base */
     mask = mask_array[HALF] | mask_array[AKHN] | mask_array[CJCT];
-    for (i = start; i < base; i++)
+    for (unsigned int i = start; i < base; i++)
       info[i].mask  |= mask;
     /* Base */
     mask = mask_array[AKHN] | mask_array[CJCT];
     info[base].mask |= mask;
     /* Post-base */
     mask = mask_array[BLWF] | mask_array[PSTF] | mask_array[CJCT];
-    for (i = base + 1; i < end; i++)
+    for (unsigned int i = base + 1; i < end; i++)
       info[i].mask  |= mask;
   }
 
   /* Apply ZWJ/ZWNJ effects */
-  for (i = start + 1; i < end; i++)
+  for (unsigned int i = start + 1; i < end; i++)
     if (is_joiner (info[i])) {
       bool non_joiner = info[i].indic_category() == OT_ZWNJ;
       unsigned int j = i;
 
       do {
         j--;
 
-        /* Reading the Unicode and OpenType specs, I think the following line
-         * is correct, but this is not what the test suite expects currently.
-         * The test suite has been drinking, not me...  But disable while
-         * investigating.
-         */
-        //info[j].mask &= !mask_array[CJCT];
+        info[j].mask &= ~mask_array[CJCT];
         if (non_joiner)
-          info[j].mask &= !mask_array[HALF];
+          info[j].mask &= ~mask_array[HALF];
 
       } while (j > start && !is_consonant (info[j]));
     }
 }
 
 
 static void
-found_vowel_syllable (const hb_ot_map_t *map, hb_buffer_t *buffer, hb_mask_t *mask_array,
-                      unsigned int start, unsigned int end)
+initial_reordering_vowel_syllable (const hb_ot_map_t *map,
+                                   hb_buffer_t *buffer,
+                                   hb_mask_t *mask_array,
+                                   unsigned int start, unsigned int end)
 {
-  /* TODO
-   * Not clear to me how this should work.  Do the matras move to before the
-   * independent vowel?  No idea.
-   */
+  /* We made the vowels look like consonants.  So let's call the consonant logic! */
+  initial_reordering_consonant_syllable (map, buffer, mask_array, start, end);
 }
 
 static void
-found_standalone_cluster (const hb_ot_map_t *map, hb_buffer_t *buffer, hb_mask_t *mask_array,
-                          unsigned int start, unsigned int end)
+initial_reordering_standalone_cluster (const hb_ot_map_t *map,
+                                       hb_buffer_t *buffer,
+                                       hb_mask_t *mask_array,
+                                       unsigned int start, unsigned int end)
 {
-  /* TODO
-   * Easiest thing to do here is to convert the NBSP to consonant and
-   * call found_consonant_syllable.
-   */
+  /* We treat NBSP/dotted-circle as if they are consonants, so we should just chain.
+   * Only if not in compatibility mode that is... */
+
+  if (options.uniscribe_bug_compatible)
+  {
+    /* For dotted-circle, this is what Uniscribe does:
+     * If dotted-circle is the last glyph, it just does nothing.
+     * Ie. It doesn't form Reph. */
+    if (buffer->info[end - 1].indic_category() == OT_DOTTEDCIRCLE)
+      return;
+  }
+
+  initial_reordering_consonant_syllable (map, buffer, mask_array, start, end);
 }
 
 static void
-found_non_indic (const hb_ot_map_t *map, hb_buffer_t *buffer, hb_mask_t *mask_array,
-                 unsigned int start, unsigned int end)
+initial_reordering_non_indic (const hb_ot_map_t *map HB_UNUSED,
+                              hb_buffer_t *buffer HB_UNUSED,
+                              hb_mask_t *mask_array HB_UNUSED,
+                              unsigned int start HB_UNUSED, unsigned int end HB_UNUSED)
 {
   /* Nothing to do right now.  If we ever switch to using the output
    * buffer in the reordering process, we'd need to next_glyph() here. */
 }
 
 #include "hb-ot-shape-complex-indic-machine.hh"
 
 static void
-remove_joiners (hb_buffer_t *buffer)
-{
-  /* For now we remove joiners.  However, Uniscbire seems to keep them
-   * and output a zero-width space glyph for them.  It is not clear to
-   * me how that is supposed to interact with GSUB. */
-
-  buffer->clear_output ();
-  unsigned int count = buffer->len;
-  for (buffer->idx = 0; buffer->idx < count;)
-    if (unlikely (is_joiner (buffer->info[buffer->idx])))
-      buffer->skip_glyph ();
-    else
-      buffer->next_glyph ();
-
-  buffer->swap_buffers ();
-}
-
-static void
 initial_reordering (const hb_ot_map_t *map,
-                    hb_face_t *face,
+                    hb_face_t *face HB_UNUSED,
                     hb_buffer_t *buffer,
                     void *user_data HB_UNUSED)
 {
   hb_mask_t mask_array[ARRAY_LENGTH (indic_basic_features)] = {0};
   unsigned int num_masks = ARRAY_LENGTH (indic_basic_features);
   for (unsigned int i = 0; i < num_masks; i++)
     mask_array[i] = map->get_1_mask (indic_basic_features[i].tag);
 
   find_syllables (map, buffer, mask_array);
-
-  remove_joiners (buffer);
 }
 
 static void
-final_reordering (const hb_ot_map_t *map,
-                  hb_face_t *face,
-                  hb_buffer_t *buffer,
-                  void *user_data HB_UNUSED)
+final_reordering_syllable (hb_buffer_t *buffer, hb_mask_t *mask_array,
+                           unsigned int start, unsigned int end)
 {
+  hb_glyph_info_t *info = buffer->info;
+
   /* 4. Final reordering:
    *
    * After the localized forms and basic shaping forms GSUB features have been
    * applied (see below), the shaping engine performs some final glyph
    * reordering before applying all the remaining font features to the entire
    * cluster.
-   *
-   *   o Reorder matras:
+   */
+
+  /* Find base again */
+  unsigned int base = end;
+  for (unsigned int i = start; i < end; i++)
+    if (info[i].indic_position() == POS_BASE_C) {
+      base = i;
+      break;
+    }
+
+  if (base == start) {
+    /* There's no Reph, and no left Matra to reposition.  Just merge the cluster
+     * and go home. */
+    buffer->merge_clusters (start, end);
+    return;
+  }
+
+  unsigned int start_of_last_cluster = base;
+
+  /*   o Reorder matras:
    *
    *     If a pre-base matra character had been reordered before applying basic
    *     features, the glyph can be moved closer to the main consonant based on
    *     whether half-forms had been formed. Actual position for the matra is
    *     defined as “after last standalone halant glyph, after initial matra
    *     position and before the main consonant”. If ZWJ or ZWNJ follow this
    *     halant, position is moved after it.
-   *
-   *   o Reorder reph:
+   */
+
+  {
+    unsigned int new_matra_pos = base - 1;
+    while (new_matra_pos > start &&
+           !(FLAG (info[new_matra_pos].indic_category()) & (FLAG (OT_M) | FLAG (OT_H))))
+      new_matra_pos--;
+    /* If we found no Halant we are done.  Otherwise only proceed if the Halant does
+     * not belong to the Matra itself! */
+    if (info[new_matra_pos].indic_category() == OT_H &&
+        info[new_matra_pos].indic_position() != POS_PRE_M) {
+      /* -> If ZWJ or ZWNJ follow this halant, position is moved after it. */
+      if (new_matra_pos + 1 < end && is_joiner (info[new_matra_pos + 1]))
+        new_matra_pos++;
+
+      /* Now go see if there's actually any matras... */
+      for (unsigned int i = new_matra_pos; i > start; i--)
+        if (info[i - 1].indic_position () == POS_PRE_M)
+        {
+          unsigned int old_matra_pos = i - 1;
+          hb_glyph_info_t matra = info[old_matra_pos];
+          memmove (&info[old_matra_pos], &info[old_matra_pos + 1], (new_matra_pos - old_matra_pos) * sizeof (info[0]));
+          info[new_matra_pos] = matra;
+          start_of_last_cluster = MIN (new_matra_pos, start_of_last_cluster);
+          new_matra_pos--;
+        }
+    }
+  }
+
+
+  /*   o Reorder reph:
    *
    *     Reph’s original position is always at the beginning of the syllable,
    *     (i.e. it is not reordered at the character reordering stage). However,
    *     it will be reordered according to the basic-forms shaping results.
    *     Possible positions for reph, depending on the script, are; after main,
    *     before post-base consonant forms, and after post-base consonant forms.
-   *
-   *       1. If reph should be positioned after post-base consonant forms,
-   *          proceed to step 5.
-   *
-   *       2. If the reph repositioning class is not after post-base: target
-   *          position is after the first explicit halant glyph between the
-   *          first post-reph consonant and last main consonant. If ZWJ or ZWNJ
-   *          are following this halant, position is moved after it. If such
-   *          position is found, this is the target position. Otherwise,
-   *          proceed to the next step.
-   *
-   *          Note: in old-implementation fonts, where classifications were
-   *          fixed in shaping engine, there was no case where reph position
-   *          will be found on this step.
-   *
-   *       3. If reph should be repositioned after the main consonant: from the
-   *          first consonant not ligated with main, or find the first
-   *          consonant that is not a potential pre-base reordering Ra.
-   *
-   *
-   *       4. If reph should be positioned before post-base consonant, find
-   *          first post-base classified consonant not ligated with main. If no
-   *          consonant is found, the target position should be before the
-   *          first matra, syllable modifier sign or vedic sign.
-   *
-   *       5. If no consonant is found in steps 3 or 4, move reph to a position
-   *          immediately before the first post-base matra, syllable modifier
-   *          sign or vedic sign that has a reordering class after the intended
-   *          reph position. For example, if the reordering position for reph
-   *          is post-main, it will skip above-base matras that also have a
-   *          post-main position.
-   *
-   *       6. Otherwise, reorder reph to the end of the syllable.
-   *
-   *   o Reorder pre-base reordering consonants:
+   */
+
+  /* If there's anything after the Ra that has the REPH pos, it ought to be halant.
+   * Which means that the font has failed to ligate the Reph.  In which case, we
+   * shouldn't move. */
+  if (start + 1 < end &&
+      info[start].indic_position() == POS_RA_TO_BECOME_REPH &&
+      info[start + 1].indic_position() != POS_RA_TO_BECOME_REPH)
+  {
+      unsigned int new_reph_pos;
+
+     enum reph_position_t {
+       REPH_AFTER_MAIN,
+       REPH_BEFORE_SUBSCRIPT,
+       REPH_AFTER_SUBSCRIPT,
+       REPH_BEFORE_POSTSCRIPT,
+       REPH_AFTER_POSTSCRIPT,
+     } reph_pos;
+
+     /* XXX Figure out old behavior too */
+     switch ((hb_tag_t) buffer->props.script)
+     {
+       case HB_SCRIPT_MALAYALAM:
+       case HB_SCRIPT_ORIYA:
+         reph_pos = REPH_AFTER_MAIN;
+         break;
+
+       case HB_SCRIPT_GURMUKHI:
+         reph_pos = REPH_BEFORE_SUBSCRIPT;
+         break;
+
+       case HB_SCRIPT_BENGALI:
+         reph_pos = REPH_AFTER_SUBSCRIPT;
+         break;
+
+       default:
+       case HB_SCRIPT_DEVANAGARI:
+       case HB_SCRIPT_GUJARATI:
+         reph_pos = REPH_BEFORE_POSTSCRIPT;
+         break;
+
+       case HB_SCRIPT_KANNADA:
+       case HB_SCRIPT_TAMIL:
+       case HB_SCRIPT_TELUGU:
+         reph_pos = REPH_AFTER_POSTSCRIPT;
+         break;
+     }
+
+    /*       1. If reph should be positioned after post-base consonant forms,
+     *          proceed to step 5.
+     */
+    if (reph_pos == REPH_AFTER_POSTSCRIPT)
+    {
+      goto reph_step_5;
+    }
+
+    /*       2. If the reph repositioning class is not after post-base: target
+     *          position is after the first explicit halant glyph between the
+     *          first post-reph consonant and last main consonant. If ZWJ or ZWNJ
+     *          are following this halant, position is moved after it. If such
+     *          position is found, this is the target position. Otherwise,
+     *          proceed to the next step.
+     *
+     *          Note: in old-implementation fonts, where classifications were
+     *          fixed in shaping engine, there was no case where reph position
+     *          will be found on this step.
+     */
+    {
+      new_reph_pos = start + 1;
+      while (new_reph_pos < base && info[new_reph_pos].indic_category() != OT_H)
+        new_reph_pos++;
+
+      if (new_reph_pos < base && info[new_reph_pos].indic_category() == OT_H) {
+        /* ->If ZWJ or ZWNJ are following this halant, position is moved after it. */
+        if (new_reph_pos + 1 < base && is_joiner (info[new_reph_pos + 1]))
+          new_reph_pos++;
+        goto reph_move;
+      }
+    }
+
+    /*       3. If reph should be repositioned after the main consonant: find the
+     *          first consonant not ligated with main, or find the first
+     *          consonant that is not a potential pre-base reordering Ra.
+     */
+    if (reph_pos == REPH_AFTER_MAIN)
+    {
+      /* XXX */
+    }
+
+    /*       4. If reph should be positioned before post-base consonant, find
+     *          first post-base classified consonant not ligated with main. If no
+     *          consonant is found, the target position should be before the
+     *          first matra, syllable modifier sign or vedic sign.
+     */
+    /* This is our take on what step 4 is trying to say (and failing, BADLY). */
+    if (reph_pos == REPH_AFTER_SUBSCRIPT)
+    {
+      new_reph_pos = base;
+      while (new_reph_pos < end &&
+             !( FLAG (info[new_reph_pos + 1].indic_position()) & (FLAG (POS_POST_C) | FLAG (POS_POST_M) | FLAG (POS_SMVD))))
+        new_reph_pos++;
+      if (new_reph_pos < end)
+        goto reph_move;
+    }
+
+    /*       5. If no consonant is found in steps 3 or 4, move reph to a position
+     *          immediately before the first post-base matra, syllable modifier
+     *          sign or vedic sign that has a reordering class after the intended
+     *          reph position. For example, if the reordering position for reph
+     *          is post-main, it will skip above-base matras that also have a
+     *          post-main position.
+     */
+    reph_step_5:
+    {
+      /* XXX */
+    }
+
+    /*       6. Otherwise, reorder reph to the end of the syllable.
+     */
+    {
+      new_reph_pos = end - 1;
+      while (new_reph_pos > start && info[new_reph_pos].indic_position() == POS_SMVD)
+        new_reph_pos--;
+
+      /*
+       * If the Reph is to be ending up after a Matra,Halant sequence,
+       * position it before that Halant so it can interact with the Matra.
+       * However, if it's a plain Consonant,Halant we shouldn't do that.
+       * Uniscribe doesn't do this.
+       * TEST: U+0930,U+094D,U+0915,U+094B,U+094D
+       */
+      if (!options.uniscribe_bug_compatible &&
+          unlikely (info[new_reph_pos].indic_category() == OT_H)) {
+        for (unsigned int i = base + 1; i < new_reph_pos; i++)
+          if (info[i].indic_category() == OT_M) {
+            /* Ok, got it. */
+            new_reph_pos--;
+          }
+      }
+      goto reph_move;
+    }
+
+    reph_move:
+    {
+      /* Move */
+      hb_glyph_info_t reph = info[start];
+      memmove (&info[start], &info[start + 1], (new_reph_pos - start) * sizeof (info[0]));
+      info[new_reph_pos] = reph;
+      start_of_last_cluster = start; /* Yay, one big cluster! */
+    }
+  }
+
+
+  /*   o Reorder pre-base reordering consonants:
    *
    *     If a pre-base reordering consonant is found, reorder it according to
    *     the following rules:
    *
    *       1. Only reorder a glyph produced by substitution during application
    *          of the feature. (Note that a font may shape a Ra consonant with
    *          the feature generally but block it in certain contexts.)
    *
    *       2. Try to find a target position the same way as for pre-base matra.
    *          If it is found, reorder pre-base consonant glyph.
    *
    *       3. If position is not found, reorder immediately before main
    *          consonant.
    */
 
   /* TODO */
 
 
 
+  /* Apply 'init' to the Left Matra if it's a word start. */
+  if (info[start].indic_position () == POS_PRE_M &&
+      (!start ||
+       !(FLAG (_hb_glyph_info_get_general_category (&info[start - 1])) &
+         (FLAG (HB_UNICODE_GENERAL_CATEGORY_LOWERCASE_LETTER) |
+          FLAG (HB_UNICODE_GENERAL_CATEGORY_MODIFIER_LETTER) |
+          FLAG (HB_UNICODE_GENERAL_CATEGORY_OTHER_LETTER) |
+          FLAG (HB_UNICODE_GENERAL_CATEGORY_TITLECASE_LETTER) |
+          FLAG (HB_UNICODE_GENERAL_CATEGORY_UPPERCASE_LETTER) |
+          FLAG (HB_UNICODE_GENERAL_CATEGORY_SPACING_MARK) |
+          FLAG (HB_UNICODE_GENERAL_CATEGORY_ENCLOSING_MARK) |
+          FLAG (HB_UNICODE_GENERAL_CATEGORY_NON_SPACING_MARK)))))
+    info[start].mask |= mask_array[INIT];
+
+
+
+  /* Finish off the clusters and go home! */
+
+  if (!options.uniscribe_bug_compatible)
+  {
+    /* This is what Uniscribe does.  Ie. add cluster boundaries after Halant,ZWNJ.
+     * This means, half forms are submerged into the main consonants cluster.
+     * This is unnecessary, and makes cursor positioning harder, but that's what
+     * Uniscribe does. */
+    unsigned int cluster_start = start;
+    for (unsigned int i = start + 1; i < start_of_last_cluster; i++)
+      if (info[i - 1].indic_category() == OT_H && info[i].indic_category() == OT_ZWNJ) {
+        i++;
+        buffer->merge_clusters (cluster_start, i);
+        cluster_start = i;
+      }
+    start_of_last_cluster = cluster_start;
+  }
+
+  buffer->merge_clusters (start_of_last_cluster, end);
+}
+
+
+static void
+final_reordering (const hb_ot_map_t *map,
+                  hb_face_t *face HB_UNUSED,
+                  hb_buffer_t *buffer,
+                  void *user_data HB_UNUSED)
+{
+  unsigned int count = buffer->len;
+  if (!count) return;
+
+  hb_mask_t mask_array[ARRAY_LENGTH (indic_other_features)] = {0};
+  unsigned int num_masks = ARRAY_LENGTH (indic_other_features);
+  for (unsigned int i = 0; i < num_masks; i++)
+    mask_array[i] = map->get_1_mask (indic_other_features[i].tag);
+
+  hb_glyph_info_t *info = buffer->info;
+  unsigned int last = 0;
+  unsigned int last_syllable = info[0].syllable();
+  for (unsigned int i = 1; i < count; i++)
+    if (last_syllable != info[i].syllable()) {
+      final_reordering_syllable (buffer, mask_array, last, i);
+      last = i;
+      last_syllable = info[last].syllable();
+    }
+  final_reordering_syllable (buffer, mask_array, last, count);
+
   HB_BUFFER_DEALLOCATE_VAR (buffer, indic_category);
   HB_BUFFER_DEALLOCATE_VAR (buffer, indic_position);
 }