text: /*
   * Copyright © 2015  Mozilla Foundation.
   * Copyright © 2015  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.
   *
   * Mozilla Author(s): Jonathan Kew
   * Google Author(s): Behdad Esfahbod
   */
  
  #include "hb-ot-shape-complex-use-private.hh"
  #include "hb-ot-shape-complex-arabic-private.hh"
  
  /* buffer var allocations */
  #define use_category() complex_var_u8_0()
  
  
  /*
   * Universal Shaping Engine.
   * https://www.microsoft.com/typography/OpenTypeDev/USE/intro.htm
   */
  
  static const hb_tag_t
  basic_features[] =
  {
    /*
     * Basic features.
     * These features are applied all at once, before reordering.
     */
    HB_TAG('r','k','r','f'),
    HB_TAG('a','b','v','f'),
    HB_TAG('b','l','w','f'),
    HB_TAG('h','a','l','f'),
    HB_TAG('p','s','t','f'),
    HB_TAG('v','a','t','u'),
    HB_TAG('c','j','c','t'),
  };
  static const hb_tag_t
  arabic_features[] =
  {
    HB_TAG('i','s','o','l'),
    HB_TAG('i','n','i','t'),
    HB_TAG('m','e','d','i'),
    HB_TAG('f','i','n','a'),
    /* The spec doesn't specify these but we apply anyway, since our Arabic shaper
     * does.  These are only used in Syriac spec. */
    HB_TAG('m','e','d','2'),
    HB_TAG('f','i','n','2'),
    HB_TAG('f','i','n','3'),
  };
  /* Same order as arabic_features.  Don't need Syriac stuff.*/
  enum joining_form_t {
    ISOL,
    INIT,
    MEDI,
    FINA,
    _NONE
  };
  static const hb_tag_t
  other_features[] =
  {
    /*
     * Other features.
     * These features are applied all at once, after reordering.
     */
    HB_TAG('a','b','v','s'),
    HB_TAG('b','l','w','s'),
    HB_TAG('h','a','l','n'),
    HB_TAG('p','r','e','s'),
    HB_TAG('p','s','t','s'),
    /* Positioning features, though we don't care about the types. */
    HB_TAG('d','i','s','t'),
    HB_TAG('a','b','v','m'),
    HB_TAG('b','l','w','m'),
  };
  
  static void
  setup_syllables (const hb_ot_shape_plan_t *plan,
  		 hb_font_t *font,
  		 hb_buffer_t *buffer);
  static void
  clear_substitution_flags (const hb_ot_shape_plan_t *plan,
  			  hb_font_t *font,
  			  hb_buffer_t *buffer);
  static void
  record_rphf (const hb_ot_shape_plan_t *plan,
  	     hb_font_t *font,
  	     hb_buffer_t *buffer);
  static void
  record_pref (const hb_ot_shape_plan_t *plan,
  	     hb_font_t *font,
  	     hb_buffer_t *buffer);
  static void
  reorder (const hb_ot_shape_plan_t *plan,
  	 hb_font_t *font,
  	 hb_buffer_t *buffer);
  
  static void
  collect_features_use (hb_ot_shape_planner_t *plan)
  {
    hb_ot_map_builder_t *map = &plan->map;
  
    /* Do this before any lookups have been applied. */
    map->add_gsub_pause (setup_syllables);
  
    /* "Default glyph pre-processing group" */
    map->add_global_bool_feature (HB_TAG('l','o','c','l'));
    map->add_global_bool_feature (HB_TAG('c','c','m','p'));
    map->add_global_bool_feature (HB_TAG('n','u','k','t'));
    map->add_global_bool_feature (HB_TAG('a','k','h','n'));
  
    /* "Reordering group" */
    map->add_gsub_pause (clear_substitution_flags);
    map->add_feature (HB_TAG('r','p','h','f'), 1, F_MANUAL_ZWJ);
    map->add_gsub_pause (record_rphf);
    map->add_gsub_pause (clear_substitution_flags);
    map->add_feature (HB_TAG('p','r','e','f'), 1, F_GLOBAL | F_MANUAL_ZWJ);
    map->add_gsub_pause (record_pref);
  
    /* "Orthographic unit shaping group" */
    for (unsigned int i = 0; i < ARRAY_LENGTH (basic_features); i++)
      map->add_feature (basic_features[i], 1, F_GLOBAL | F_MANUAL_ZWJ);
  
    map->add_gsub_pause (reorder);
  
    /* "Topographical features" */
    for (unsigned int i = 0; i < ARRAY_LENGTH (arabic_features); i++)
      map->add_feature (arabic_features[i], 1, F_NONE);
    map->add_gsub_pause (NULL);
  
    /* "Standard typographic presentation" and "Positional feature application" */
    for (unsigned int i = 0; i < ARRAY_LENGTH (other_features); i++)
      map->add_feature (other_features[i], 1, F_GLOBAL | F_MANUAL_ZWJ);
  }
  
  struct use_shape_plan_t
  {
    ASSERT_POD ();
  
    hb_mask_t rphf_mask;
  
    arabic_shape_plan_t *arabic_plan;
  };
  
  static bool
  has_arabic_joining (hb_script_t script)
  {
    /* List of scripts that have data in arabic-table. */
    switch ((int) script)
    {
      /* Unicode-1.1 additions */
      case HB_SCRIPT_ARABIC:
  
      /* Unicode-3.0 additions */
      case HB_SCRIPT_MONGOLIAN:
      case HB_SCRIPT_SYRIAC:
  
      /* Unicode-5.0 additions */
      case HB_SCRIPT_NKO:
      case HB_SCRIPT_PHAGS_PA:
  
      /* Unicode-6.0 additions */
      case HB_SCRIPT_MANDAIC:
  
      /* Unicode-7.0 additions */
      case HB_SCRIPT_MANICHAEAN:
      case HB_SCRIPT_PSALTER_PAHLAVI:
  
        return true;
  
      default:
        return false;
    }
  }
  
  static void *
  data_create_use (const hb_ot_shape_plan_t *plan)
  {
    use_shape_plan_t *use_plan = (use_shape_plan_t *) calloc (1, sizeof (use_shape_plan_t));
    if (unlikely (!use_plan))
      return NULL;
  
    use_plan->rphf_mask = plan->map.get_1_mask (HB_TAG('r','p','h','f'));
  
    if (has_arabic_joining (plan->props.script))
    {
      use_plan->arabic_plan = (arabic_shape_plan_t *) data_create_arabic (plan);
      if (unlikely (!use_plan->arabic_plan))
      {
        free (use_plan);
        return NULL;
      }
    }
  
    return use_plan;
  }
  
  static void
  data_destroy_use (void *data)
  {
    use_shape_plan_t *use_plan = (use_shape_plan_t *) data;
  
    if (use_plan->arabic_plan)
      data_destroy_arabic (use_plan->arabic_plan);
  
    free (data);
  }
  
  enum syllable_type_t {
    independent_cluster,
    virama_terminated_cluster,
    consonant_cluster,
    vowel_cluster,
    number_joiner_terminated_cluster,
    numeral_cluster,
    symbol_cluster,
    broken_cluster,
  };
  
  #include "hb-ot-shape-complex-use-machine.hh"
  
  
  static void
  setup_masks_use (const hb_ot_shape_plan_t *plan,
  		 hb_buffer_t              *buffer,
  		 hb_font_t                *font HB_UNUSED)
  {
    const use_shape_plan_t *use_plan = (const use_shape_plan_t *) plan->data;
  
    /* Do this before allocating use_category(). */
    if (use_plan->arabic_plan)
    {
      setup_masks_arabic_plan (use_plan->arabic_plan, buffer, plan->props.script);
    }
  
    HB_BUFFER_ALLOCATE_VAR (buffer, use_category);
  
    /* We cannot setup masks here.  We save information about characters
     * and setup masks later on in a pause-callback. */
  
    unsigned int count = buffer->len;
    hb_glyph_info_t *info = buffer->info;
    for (unsigned int i = 0; i < count; i++)
      info[i].use_category() = hb_use_get_categories (info[i].codepoint);
  }
  
  static void
  setup_rphf_mask (const hb_ot_shape_plan_t *plan,
  		 hb_buffer_t *buffer)
  {
    const use_shape_plan_t *use_plan = (const use_shape_plan_t *) plan->data;
  
    hb_mask_t mask = use_plan->rphf_mask;
    if (!mask) return;
  
    hb_glyph_info_t *info = buffer->info;
  
    foreach_syllable (buffer, start, end)
    {
      unsigned int limit = info[start].use_category() == USE_R ? 1 : MIN (3u, end - start);
      for (unsigned int i = start; i < start + limit; i++)
        info[i].mask |= mask;
    }
  }
  
  static void
  setup_topographical_masks (const hb_ot_shape_plan_t *plan,
  			   hb_buffer_t *buffer)
  {
    const use_shape_plan_t *use_plan = (const use_shape_plan_t *) plan->data;
    if (use_plan->arabic_plan)
      return;
  
    ASSERT_STATIC (INIT < 4 && ISOL < 4 && MEDI < 4 && FINA < 4);
    hb_mask_t masks[4], all_masks = 0;
    for (unsigned int i = 0; i < 4; i++)
    {
      masks[i] = plan->map.get_1_mask (arabic_features[i]);
      if (masks[i] == plan->map.get_global_mask ())
        masks[i] = 0;
      all_masks |= masks[i];
    }
    if (!all_masks)
      return;
    hb_mask_t other_masks = ~all_masks;
  
    unsigned int last_start = 0;
    joining_form_t last_form = _NONE;
    hb_glyph_info_t *info = buffer->info;
    foreach_syllable (buffer, start, end)
    {
      syllable_type_t syllable_type = (syllable_type_t) (info[start].syllable() & 0x0F);
      switch (syllable_type)
      {
        case independent_cluster:
        case symbol_cluster:
  	/* These don't join.  Nothing to do. */
  	last_form = _NONE;
  	break;
  
        case virama_terminated_cluster:
        case consonant_cluster:
        case vowel_cluster:
        case number_joiner_terminated_cluster:
        case numeral_cluster:
        case broken_cluster:
  
  	bool join = last_form == FINA || last_form == ISOL;
  
  	if (join)
  	{
  	  /* Fixup previous syllable's form. */
  	  last_form = last_form == FINA ? MEDI : INIT;
  	  for (unsigned int i = last_start; i < start; i++)
  	    info[i].mask = (info[i].mask & other_masks) | masks[last_form];
  	}
  
  	/* Form for this syllable. */
  	last_form = join ? FINA : ISOL;
  	for (unsigned int i = start; i < end; i++)
  	  info[i].mask = (info[i].mask & other_masks) | masks[last_form];
  
  	break;
      }
  
      last_start = start;
    }
  }
  
  static void
  setup_syllables (const hb_ot_shape_plan_t *plan,
  		 hb_font_t *font HB_UNUSED,
  		 hb_buffer_t *buffer)
  {
    find_syllables (buffer);
    setup_rphf_mask (plan, buffer);
    setup_topographical_masks (plan, buffer);
  }
  
  static void
  clear_substitution_flags (const hb_ot_shape_plan_t *plan,
  			  hb_font_t *font HB_UNUSED,
  			  hb_buffer_t *buffer)
  {
    hb_glyph_info_t *info = buffer->info;
    unsigned int count = buffer->len;
    for (unsigned int i = 0; i < count; i++)
      _hb_glyph_info_clear_substituted (&info[i]);
  }
  
  static void
  record_rphf (const hb_ot_shape_plan_t *plan,
  	     hb_font_t *font,
  	     hb_buffer_t *buffer)
  {
    const use_shape_plan_t *use_plan = (const use_shape_plan_t *) plan->data;
  
    hb_mask_t mask = use_plan->rphf_mask;
    if (!mask) return;
    hb_glyph_info_t *info = buffer->info;
  
    foreach_syllable (buffer, start, end)
    {
      /* Mark a substituted repha as USE_R. */
      for (unsigned int i = start; i < end && (info[i].mask & mask); i++)
        if (_hb_glyph_info_substituted (&info[i]))
        {
  	info[i].use_category() = USE_R;
  	break;
        }
    }
  }
  
  static void
  record_pref (const hb_ot_shape_plan_t *plan,
  	     hb_font_t *font,
  	     hb_buffer_t *buffer)
  {
    hb_glyph_info_t *info = buffer->info;
  
    foreach_syllable (buffer, start, end)
    {
      /* Mark a substituted pref as VPre, as they behave the same way. */
      for (unsigned int i = start; i < end; i++)
        if (_hb_glyph_info_substituted (&info[i]))
        {
  	info[i].use_category() = USE_VPre;
  	break;
        }
    }
  }
  
  static inline bool
  is_halant (const hb_glyph_info_t &info)
  {
    return info.use_category() == USE_H && !_hb_glyph_info_ligated (&info);
  }
  
  static void
  reorder_syllable (hb_buffer_t *buffer, unsigned int start, unsigned int end)
  {
    syllable_type_t syllable_type = (syllable_type_t) (buffer->info[start].syllable() & 0x0F);
    /* Only a few syllable types need reordering. */
    if (unlikely (!(FLAG_SAFE (syllable_type) &
  		  (FLAG (virama_terminated_cluster) |
  		   FLAG (consonant_cluster) |
  		   FLAG (vowel_cluster) |
  		   FLAG (broken_cluster) |
  		   0))))
      return;
  
    hb_glyph_info_t *info = buffer->info;
  
  #define BASE_FLAGS (FLAG (USE_B) | FLAG (USE_GB) | FLAG (USE_IV))
  
    /* 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. */
      for (unsigned int i = start + 1; i < end; i++)
        if ((FLAG_UNSAFE (info[i].use_category()) & (BASE_FLAGS)) || is_halant (info[i]))
        {
  	/* If we hit a halant, move before it; otherwise it's a base: move to it's
  	 * place, and shift things in between backward. */
  
  	if (is_halant (info[i]))
  	  i--;
  
  	buffer->merge_clusters (start, i + 1);
  	hb_glyph_info_t t = info[start];
  	memmove (&info[start], &info[start + 1], (i - start) * sizeof (info[0]));
  	info[i] = t;
  
  	break;
        }
    }
  
    /* Move things back. */
    unsigned int j = end;
    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 we hit a halant, move after it; otherwise it's a base: move to it's
         * place, and shift things in between backward. */
        if (is_halant (info[i]))
  	j = i + 1;
        else
  	j = i;
      }
      else if (((flag) & (FLAG (USE_VPre) | FLAG (USE_VMPre))) &&
  	     /* Only move the first component of a MultipleSubst. */
  	     0 == _hb_glyph_info_get_lig_comp (&info[i]) &&
  	     j < i)
      {
        buffer->merge_clusters (j, i + 1);
        hb_glyph_info_t t = info[i];
        memmove (&info[j + 1], &info[j], (i - j) * sizeof (info[0]));
        info[j] = t;
      }
    }
  }
  
  static inline void
  insert_dotted_circles (const hb_ot_shape_plan_t *plan HB_UNUSED,
  		       hb_font_t *font,
  		       hb_buffer_t *buffer)
  {
    /* Note: This loop is extra overhead, but should not be measurable. */
    bool has_broken_syllables = false;
    unsigned int count = buffer->len;
    hb_glyph_info_t *info = buffer->info;
    for (unsigned int i = 0; i < count; i++)
      if ((info[i].syllable() & 0x0F) == broken_cluster)
      {
        has_broken_syllables = true;
        break;
      }
    if (likely (!has_broken_syllables))
      return;
  
    hb_glyph_info_t dottedcircle = {0};
    if (!font->get_nominal_glyph (0x25CCu, &dottedcircle.codepoint))
      return;
    dottedcircle.use_category() = hb_use_get_categories (0x25CC);
  
    buffer->clear_output ();
  
    buffer->idx = 0;
    unsigned int last_syllable = 0;
    while (buffer->idx < buffer->len && !buffer->in_error)
    {
      unsigned int syllable = buffer->cur().syllable();
      syllable_type_t syllable_type = (syllable_type_t) (syllable & 0x0F);
      if (unlikely (last_syllable != syllable && syllable_type == broken_cluster))
      {
        last_syllable = syllable;
  
        hb_glyph_info_t ginfo = dottedcircle;
        ginfo.cluster = buffer->cur().cluster;
        ginfo.mask = buffer->cur().mask;
        ginfo.syllable() = buffer->cur().syllable();
        /* TODO Set glyph_props? */
  
        /* Insert dottedcircle after possible Repha. */
        while (buffer->idx < buffer->len && !buffer->in_error &&
  	     last_syllable == buffer->cur().syllable() &&
  	     buffer->cur().use_category() == USE_R)
          buffer->next_glyph ();
  
        buffer->output_info (ginfo);
      }
      else
        buffer->next_glyph ();
    }
  
    buffer->swap_buffers ();
  }
  
  static void
  reorder (const hb_ot_shape_plan_t *plan,
  	 hb_font_t *font,
  	 hb_buffer_t *buffer)
  {
    insert_dotted_circles (plan, font, buffer);
  
    hb_glyph_info_t *info = buffer->info;
  
    foreach_syllable (buffer, start, end)
      reorder_syllable (buffer, start, end);
  
    /* Zero syllables now... */
    unsigned int count = buffer->len;
    for (unsigned int i = 0; i < count; i++)
      info[i].syllable() = 0;
  
    HB_BUFFER_DEALLOCATE_VAR (buffer, use_category);
  }
  
  static bool
  compose_use (const hb_ot_shape_normalize_context_t *c,
  	     hb_codepoint_t  a,
  	     hb_codepoint_t  b,
  	     hb_codepoint_t *ab)
  {
    /* Avoid recomposing split matras. */
    if (HB_UNICODE_GENERAL_CATEGORY_IS_MARK (c->unicode->general_category (a)))
      return false;
  
    return (bool)c->unicode->compose (a, b, ab);
  }
  
  
  const hb_ot_complex_shaper_t _hb_ot_complex_shaper_use =
  {
    "use",
    collect_features_use,
    NULL, /* override_features */
    data_create_use,
    data_destroy_use,
    NULL, /* preprocess_text */
    NULL, /* postprocess_glyphs */
    HB_OT_SHAPE_NORMALIZATION_MODE_COMPOSED_DIACRITICS_NO_SHORT_CIRCUIT,
    NULL, /* decompose */
    compose_use,
    setup_masks_use,
    HB_OT_SHAPE_ZERO_WIDTH_MARKS_BY_GDEF_EARLY,
    false, /* fallback_position */
  };
  