Roll HarfBuzz to 0.9.32

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

 /*
  * Copyright © 2010,2012  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.
@@ skipping 39 matching lines @@
 };
 
 /*
  * Joining types:
  */
 
 #include "hb-ot-shape-complex-arabic-table.hh"
 
 static unsigned int get_joining_type (hb_codepoint_t u, hb_unicode_general_category_t gen_cat)
 {
-  if (likely (hb_in_range<hb_codepoint_t> (u, JOINING_TABLE_FIRST, JOINING_TABLE_LAST))) {
-    unsigned int j_type = joining_table[u - JOINING_TABLE_FIRST];
-    if (likely (j_type != JOINING_TYPE_X))
-      return j_type;
-  }
+  unsigned int j_type = joining_type(u);
+  if (likely (j_type != JOINING_TYPE_X))
+    return j_type;
 
-  /* Mongolian joining data is not in ArabicJoining.txt yet. */
-  if (unlikely (hb_in_range<hb_codepoint_t> (u, 0x1800, 0x18AF)))
-  {
-    if (unlikely (hb_in_range<hb_codepoint_t> (u, 0x1880, 0x1886)))
-      return JOINING_TYPE_U;
+  return (FLAG(gen_cat) &
+          (FLAG(HB_UNICODE_GENERAL_CATEGORY_NON_SPACING_MARK) |
+           FLAG(HB_UNICODE_GENERAL_CATEGORY_ENCLOSING_MARK) |
+           FLAG(HB_UNICODE_GENERAL_CATEGORY_FORMAT))
+         ) ?  JOINING_TYPE_T : JOINING_TYPE_U;
+}
 
-    /* All letters, SIBE SYLLABLE BOUNDARY MARKER, and NIRUGU are D */
-    if ((FLAG(gen_cat) & (FLAG (HB_UNICODE_GENERAL_CATEGORY_OTHER_LETTER) |
-                          FLAG (HB_UNICODE_GENERAL_CATEGORY_MODIFIER_LETTER)))
-        || u == 0x1807 || u == 0x180A)
-      return JOINING_TYPE_D;
-  }
-
-  /* 'Phags-pa joining data is not in ArabicJoining.txt yet. */
-  if (unlikely (hb_in_range<hb_codepoint_t> (u, 0xA840, 0xA872)))
-  {
-      if (unlikely (u == 0xA872))
-        return JOINING_TYPE_L;
-
-      return JOINING_TYPE_D;
-  }
-
-  if (unlikely (hb_in_range<hb_codepoint_t> (u, 0x200C, 0x200D)))
-  {
-    return u == 0x200C ? JOINING_TYPE_U : JOINING_TYPE_C;
-  }
-
-  return (FLAG(gen_cat) & (FLAG(HB_UNICODE_GENERAL_CATEGORY_NON_SPACING_MARK) | FLAG(HB_UNICODE_GENERAL_CATEGORY_ENCLOSING_MARK) | FLAG(HB_UNICODE_GENERAL_CATEGORY_FORMAT))) ?
-         JOINING_TYPE_T : JOINING_TYPE_U;
-}
+#define FEATURE_IS_SYRIAC(tag) hb_in_range<unsigned char> ((unsigned char) (tag), '2', '3')
 
 static const hb_tag_t arabic_features[] =
 {
-  HB_TAG('i','n','i','t'),
-  HB_TAG('m','e','d','i'),
+  HB_TAG('i','s','o','l'),
   HB_TAG('f','i','n','a'),
-  HB_TAG('i','s','o','l'),
-  /* Syriac */
-  HB_TAG('m','e','d','2'),
   HB_TAG('f','i','n','2'),
   HB_TAG('f','i','n','3'),
+  HB_TAG('m','e','d','i'),
+  HB_TAG('m','e','d','2'),
+  HB_TAG('i','n','i','t'),
   HB_TAG_NONE
 };
 
 
 /* Same order as the feature array */
 enum {
-  INIT,
-  MEDI,
+  ISOL,
   FINA,
-  ISOL,
-
-  /* Syriac */
-  MED2,
   FIN2,
   FIN3,
+  MEDI,
+  MED2,
+  INIT,
 
   NONE,
 
   ARABIC_NUM_FEATURES = NONE
 };
 
 static const struct arabic_state_table_entry {
         uint8_t prev_action;
         uint8_t curr_action;
         uint16_t next_state;
@@ skipping 32 matching lines @@
 static void
 arabic_fallback_shape (const hb_ot_shape_plan_t *plan,
                        hb_font_t *font,
                        hb_buffer_t *buffer);
 
 static void
 collect_features_arabic (hb_ot_shape_planner_t *plan)
 {
   hb_ot_map_builder_t *map = &plan->map;
 
-  /* For Language forms (in ArabicOT speak), we do the iso/fina/medi/init together,
-   * then rlig and calt each in their own stage.  This makes IranNastaliq's ALLAH
-   * ligature work correctly. It's unfortunate though...
+  /* We apply features according to the Arabic spec, with pauses
+   * in between most.
    *
-   * This also makes Arial Bold in Windows7 work.  See:
+   * The pause between init/medi/... and rlig is required.  See eg:
    * https://bugzilla.mozilla.org/show_bug.cgi?id=644184
    *
-   * TODO: Add test cases for these two.
+   * The pauses between init/medi/... themselves are not necessarily
+   * needed as only one of those features is applied to any character.
+   * The only difference it makes is when fonts have contextual
+   * substitutions.  We now follow the order of the spec, which makes
+   * for better experience if that's what Uniscribe is doing.
+   *
+   * At least for Arabic, looks like Uniscribe has a pause between
+   * rlig and calt.  Otherwise the IranNastaliq's ALLAH ligature won't
+   * work.  However, testing shows that rlig and calt are applied
+   * together for Mongolian in Uniscribe.  As such, we only add a
+   * pause for Arabic, not other scripts.
    */
 
   map->add_gsub_pause (nuke_joiners);
 
   map->add_global_bool_feature (HB_TAG('c','c','m','p'));
   map->add_global_bool_feature (HB_TAG('l','o','c','l'));
 
   map->add_gsub_pause (NULL);
 
   for (unsigned int i = 0; i < ARABIC_NUM_FEATURES; i++)
-    map->add_feature (arabic_features[i], 1, i < 4 ? F_HAS_FALLBACK : F_NONE); /* The first four features have fallback. */
-
-  map->add_gsub_pause (NULL);
+  {
+    bool has_fallback = plan->props.script == HB_SCRIPT_ARABIC && !FEATURE_IS_SYRIAC (arabic_features[i]);
+    map->add_feature (arabic_features[i], 1, has_fallback ? F_HAS_FALLBACK : F_NONE);
+    map->add_gsub_pause (NULL);
+  }
 
   map->add_feature (HB_TAG('r','l','i','g'), 1, F_GLOBAL|F_HAS_FALLBACK);
-  map->add_gsub_pause (arabic_fallback_shape);
+  if (plan->props.script == HB_SCRIPT_ARABIC)
+    map->add_gsub_pause (arabic_fallback_shape);
 
   map->add_global_bool_feature (HB_TAG('c','a','l','t'));
   map->add_gsub_pause (NULL);
 
+  /* The spec includes 'cswh'.  Earlier versions of Windows
+   * used to enable this by default, but testing suggests
+   * that Windows 8 and later do not enable it by default,
+   * and spec now says 'Off by default'.
+   * We disabled this in ae23c24c32.
+   * Note that IranNastaliq uses this feature extensively
+   * to fixup broken glyph sequences.  Oh well...
+   * Test case: U+0643,U+0640,U+0631. */
+  //map->add_global_bool_feature (HB_TAG('c','s','w','h'));
   map->add_global_bool_feature (HB_TAG('m','s','e','t'));
 }
 
 #include "hb-ot-shape-complex-arabic-fallback.hh"
 
 struct arabic_shape_plan_t
 {
   ASSERT_POD ();
 
   /* The "+ 1" in the next array is to accommodate for the "NONE" command,
    * which is not an OpenType feature, but this simplifies the code by not
    * having to do a "if (... < NONE) ..." and just rely on the fact that
    * mask_array[NONE] == 0. */
   hb_mask_t mask_array[ARABIC_NUM_FEATURES + 1];
 
   bool do_fallback;
   arabic_fallback_plan_t *fallback_plan;
 };
 
 static void *
 data_create_arabic (const hb_ot_shape_plan_t *plan)
 {
   arabic_shape_plan_t *arabic_plan = (arabic_shape_plan_t *) calloc (1, sizeof (arabic_shape_plan_t));
   if (unlikely (!arabic_plan))
     return NULL;
 
   arabic_plan->do_fallback = plan->props.script == HB_SCRIPT_ARABIC;
   for (unsigned int i = 0; i < ARABIC_NUM_FEATURES; i++) {
     arabic_plan->mask_array[i] = plan->map.get_1_mask (arabic_features[i]);
-    if (i < 4)
-      arabic_plan->do_fallback = arabic_plan->do_fallback && plan->map.needs_fallback (arabic_features[i]);
+    arabic_plan->do_fallback = arabic_plan->do_fallback &&
+                               !FEATURE_IS_SYRIAC (arabic_features[i]) &&
+                               plan->map.needs_fallback (arabic_features[i]);
   }
 
   return arabic_plan;
 }
 
 static void
 data_destroy_arabic (void *data)
 {
   arabic_shape_plan_t *arabic_plan = (arabic_shape_plan_t *) data;
 
   arabic_fallback_plan_destroy (arabic_plan->fallback_plan);
 
   free (data);
 }
 
 static void
 arabic_joining (hb_buffer_t *buffer)
 {
   unsigned int count = buffer->len;
+  hb_glyph_info_t *info = buffer->info;
   unsigned int prev = (unsigned int) -1, state = 0;
 
-  HB_BUFFER_ALLOCATE_VAR (buffer, arabic_shaping_action);
-
   /* Check pre-context */
   if (!(buffer->flags & HB_BUFFER_FLAG_BOT))
     for (unsigned int i = 0; i < buffer->context_len[0]; i++)
     {
       unsigned int this_type = get_joining_type (buffer->context[0][i], buffer->unicode->general_category (buffer->context[0][i]));
 
       if (unlikely (this_type == JOINING_TYPE_T))
         continue;
 
       const arabic_state_table_entry *entry = &arabic_state_table[state][this_type];
       state = entry->next_state;
       break;
     }
 
   for (unsigned int i = 0; i < count; i++)
   {
-    unsigned int this_type = get_joining_type (buffer->info[i].codepoint, _hb_glyph_info_get_general_category (&buffer->info[i]));
+    unsigned int this_type = get_joining_type (info[i].codepoint, _hb_glyph_info_get_general_category (&info[i]));
 
     if (unlikely (this_type == JOINING_TYPE_T)) {
-      buffer->info[i].arabic_shaping_action() = NONE;
+      info[i].arabic_shaping_action() = NONE;
       continue;
     }
 
     const arabic_state_table_entry *entry = &arabic_state_table[state][this_type];
 
     if (entry->prev_action != NONE && prev != (unsigned int) -1)
-      for (; prev < i; prev++)
-        buffer->info[prev].arabic_shaping_action() = entry->prev_action;
+      info[prev].arabic_shaping_action() = entry->prev_action;
 
-    buffer->info[i].arabic_shaping_action() = entry->curr_action;
+    info[i].arabic_shaping_action() = entry->curr_action;
 
     prev = i;
     state = entry->next_state;
   }
 
   if (!(buffer->flags & HB_BUFFER_FLAG_EOT))
     for (unsigned int i = 0; i < buffer->context_len[1]; i++)
     {
       unsigned int this_type = get_joining_type (buffer->context[1][i], buffer->unicode->general_category (buffer->context[1][i]));
 
       if (unlikely (this_type == JOINING_TYPE_T))
         continue;
 
       const arabic_state_table_entry *entry = &arabic_state_table[state][this_type];
       if (entry->prev_action != NONE && prev != (unsigned int) -1)
-        buffer->info[prev].arabic_shaping_action() = entry->prev_action;
+        info[prev].arabic_shaping_action() = entry->prev_action;
       break;
     }
-
-
-  HB_BUFFER_DEALLOCATE_VAR (buffer, arabic_shaping_action);
 }
 
 static void
+mongolian_variation_selectors (hb_buffer_t *buffer)
+{
+  /* Copy arabic_shaping_action() from base to Mongolian variation selectors. */
+  unsigned int count = buffer->len;
+  hb_glyph_info_t *info = buffer->info;
+  for (unsigned int i = 1; i < count; i++)
+    if (unlikely (hb_in_range (info[i].codepoint, 0x180Bu, 0x180Du)))
+      info[i].arabic_shaping_action() = info[i - 1].arabic_shaping_action();
+}
+
+static void
 setup_masks_arabic (const hb_ot_shape_plan_t *plan,
                     hb_buffer_t              *buffer,
                     hb_font_t                *font HB_UNUSED)
 {
+  HB_BUFFER_ALLOCATE_VAR (buffer, arabic_shaping_action);
+
   const arabic_shape_plan_t *arabic_plan = (const arabic_shape_plan_t *) plan->data;
 
   arabic_joining (buffer);
+  if (plan->props.script == HB_SCRIPT_MONGOLIAN)
+    mongolian_variation_selectors (buffer);
+
   unsigned int count = buffer->len;
+  hb_glyph_info_t *info = buffer->info;
   for (unsigned int i = 0; i < count; i++)
-    buffer->info[i].mask |= arabic_plan->mask_array[buffer->info[i].arabic_shaping_action()];
+    info[i].mask |= arabic_plan->mask_array[info[i].arabic_shaping_action()];
+
+  HB_BUFFER_DEALLOCATE_VAR (buffer, arabic_shaping_action);
 }
 
 
 static void
 nuke_joiners (const hb_ot_shape_plan_t *plan HB_UNUSED,
               hb_font_t *font HB_UNUSED,
               hb_buffer_t *buffer)
 {
   unsigned int count = buffer->len;
+  hb_glyph_info_t *info = buffer->info;
   for (unsigned int i = 0; i < count; i++)
-    if (_hb_glyph_info_is_zwj (&buffer->info[i]))
-      _hb_glyph_info_flip_joiners (&buffer->info[i]);
+    if (_hb_glyph_info_is_zwj (&info[i]))
+      _hb_glyph_info_flip_joiners (&info[i]);
 }
 
 static void
 arabic_fallback_shape (const hb_ot_shape_plan_t *plan,
                        hb_font_t *font,
                        hb_buffer_t *buffer)
 {
   const arabic_shape_plan_t *arabic_plan = (const arabic_shape_plan_t *) plan->data;
 
   if (!arabic_plan->do_fallback)
@@ skipping 23 matching lines @@
   data_create_arabic,
   data_destroy_arabic,
   NULL, /* preprocess_text_arabic */
   HB_OT_SHAPE_NORMALIZATION_MODE_DEFAULT,
   NULL, /* decompose */
   NULL, /* compose */
   setup_masks_arabic,
   HB_OT_SHAPE_ZERO_WIDTH_MARKS_BY_GDEF_LATE,
   true, /* fallback_position */
 };