tor-browser

hb-ot-map.cc (12733B)

---

/*
* Copyright © 2009,2010  Red Hat, Inc.
* Copyright © 2010,2011,2013  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.
*
* Red Hat Author(s): Behdad Esfahbod
* Google Author(s): Behdad Esfahbod
*/

#include "hb.hh"

#ifndef HB_NO_OT_SHAPE

#include "hb-ot-map.hh"
#include "hb-ot-shape.hh"
#include "hb-ot-layout.hh"


void hb_ot_map_t::collect_lookups (unsigned int table_index, hb_set_t *lookups_out) const
{
 for (unsigned int i = 0; i < lookups[table_index].length; i++)
   lookups_out->add (lookups[table_index][i].index);
}


hb_ot_map_builder_t::hb_ot_map_builder_t (hb_face_t *face_,
				  const hb_segment_properties_t &props_)
{
 hb_memset (this, 0, sizeof (*this));

 feature_infos.init ();
 for (unsigned int table_index = 0; table_index < 2; table_index++)
   stages[table_index].init ();

 face = face_;
 props = props_;

 /* Fetch script/language indices for GSUB/GPOS.  We need these later to skip
  * features not available in either table and not waste precious bits for them. */

 unsigned int script_count = HB_OT_MAX_TAGS_PER_SCRIPT;
 unsigned int language_count = HB_OT_MAX_TAGS_PER_LANGUAGE;
 hb_tag_t script_tags[HB_OT_MAX_TAGS_PER_SCRIPT];
 hb_tag_t language_tags[HB_OT_MAX_TAGS_PER_LANGUAGE];

 hb_ot_tags_from_script_and_language (props.script,
			       props.language,
			       &script_count,
			       script_tags,
			       &language_count,
			       language_tags);

 for (unsigned int table_index = 0; table_index < 2; table_index++)
 {
   hb_tag_t table_tag = table_tags[table_index];
   found_script[table_index] = (bool) hb_ot_layout_table_select_script (face,
								 table_tag,
								 script_count,
								 script_tags,
								 &script_index[table_index],
								 &chosen_script[table_index]);
   hb_ot_layout_script_select_language (face,
				 table_tag,
				 script_index[table_index],
				 language_count,
				 language_tags,
				 &language_index[table_index]);
 }
}

hb_ot_map_builder_t::~hb_ot_map_builder_t ()
{
 feature_infos.fini ();
 for (unsigned int table_index = 0; table_index < 2; table_index++)
   stages[table_index].fini ();
}

void hb_ot_map_builder_t::add_feature (hb_tag_t tag,
			       hb_ot_map_feature_flags_t flags,
			       unsigned int value)
{
 if (unlikely (!tag)) return;
 feature_info_t *info = feature_infos.push();
 info->tag = tag;
 info->seq = feature_infos.length;
 info->max_value = value;
 info->flags = flags;
 info->default_value = (flags & F_GLOBAL) ? value : 0;
 info->stage[0] = current_stage[0];
 info->stage[1] = current_stage[1];
}

bool hb_ot_map_builder_t::has_feature (hb_tag_t tag)
{
 for (unsigned int table_index = 0; table_index < 2; table_index++)
 {
   if (hb_ot_layout_language_find_feature (face,
				    table_tags[table_index],
				    script_index[table_index],
				    language_index[table_index],
				    tag,
				    nullptr))
     return true;
 }
 return false;
}

void
hb_ot_map_builder_t::add_lookups (hb_ot_map_t  &m,
			  unsigned int  table_index,
			  unsigned int  feature_index,
			  unsigned int  variations_index,
			  hb_mask_t     mask,
			  bool          auto_zwnj,
			  bool          auto_zwj,
			  bool          random,
			  bool          per_syllable,
			  hb_tag_t      feature_tag)
{
 unsigned int lookup_indices[32];
 unsigned int offset, len;
 unsigned int table_lookup_count;

 table_lookup_count = hb_ot_layout_table_get_lookup_count (face, table_tags[table_index]);

 offset = 0;
 do {
   len = ARRAY_LENGTH (lookup_indices);
   hb_ot_layout_feature_with_variations_get_lookups (face,
					      table_tags[table_index],
					      feature_index,
					      variations_index,
					      offset, &len,
					      lookup_indices);

   for (unsigned int i = 0; i < len; i++)
   {
     if (lookup_indices[i] >= table_lookup_count)
continue;
     hb_ot_map_t::lookup_map_t *lookup = m.lookups[table_index].push ();
     lookup->mask = mask;
     lookup->index = lookup_indices[i];
     lookup->auto_zwnj = auto_zwnj;
     lookup->auto_zwj = auto_zwj;
     lookup->random = random;
     lookup->per_syllable = per_syllable;
     lookup->feature_tag = feature_tag;
   }

   offset += len;
 } while (len == ARRAY_LENGTH (lookup_indices));
}


void hb_ot_map_builder_t::add_pause (unsigned int table_index, hb_ot_map_t::pause_func_t pause_func)
{
 stage_info_t *s = stages[table_index].push ();
 s->index = current_stage[table_index];
 s->pause_func = pause_func;

 current_stage[table_index]++;
}

void
hb_ot_map_builder_t::compile (hb_ot_map_t                  &m,
		      const hb_ot_shape_plan_key_t &key)
{
 unsigned int global_bit_shift = 8 * sizeof (hb_mask_t) - 1;
 unsigned int global_bit_mask = 1u << global_bit_shift;

 m.global_mask = global_bit_mask;

 unsigned int required_feature_index[2];
 hb_tag_t required_feature_tag[2];
 /* We default to applying required feature in stage 0.  If the required
  * feature has a tag that is known to the shaper, we apply required feature
  * in the stage for that tag.
  */
 unsigned int required_feature_stage[2] = {0, 0};

 for (unsigned int table_index = 0; table_index < 2; table_index++)
 {
   m.chosen_script[table_index] = chosen_script[table_index];
   m.found_script[table_index] = found_script[table_index];

   hb_ot_layout_language_get_required_feature (face,
					table_tags[table_index],
					script_index[table_index],
					language_index[table_index],
					&required_feature_index[table_index],
					&required_feature_tag[table_index]);
 }

 /* Sort features and merge duplicates */
 if (feature_infos.length)
 {
   if (!is_simple)
     feature_infos.qsort ();
   auto *f = feature_infos.arrayZ;
   unsigned int j = 0;
   unsigned count = feature_infos.length;
   for (unsigned int i = 1; i < count; i++)
     if (f[i].tag != f[j].tag)
f[++j] = f[i];
     else {
if (f[i].flags & F_GLOBAL) {
  f[j].flags |= F_GLOBAL;
  f[j].max_value = f[i].max_value;
  f[j].default_value = f[i].default_value;
} else {
  if (f[j].flags & F_GLOBAL)
    f[j].flags ^= F_GLOBAL;
  f[j].max_value = hb_max (f[j].max_value, f[i].max_value);
  /* Inherit default_value from j */
}
f[j].flags |= (f[i].flags & F_HAS_FALLBACK);
f[j].stage[0] = hb_min (f[j].stage[0], f[i].stage[0]);
f[j].stage[1] = hb_min (f[j].stage[1], f[i].stage[1]);
     }
   feature_infos.shrink (j + 1);
 }

 hb_map_t feature_indices[2];
 for (unsigned int table_index = 0; table_index < 2; table_index++)
   hb_ot_layout_collect_features_map (face,
			       table_tags[table_index],
			       script_index[table_index],
			       language_index[table_index],
			       &feature_indices[table_index]);

 /* Allocate bits now */
 static_assert ((!(HB_GLYPH_FLAG_DEFINED & (HB_GLYPH_FLAG_DEFINED + 1))), "");
 unsigned int next_bit = hb_popcount (HB_GLYPH_FLAG_DEFINED) + 1;

 unsigned count = feature_infos.length;
 for (unsigned int i = 0; i < count; i++)
 {
   const feature_info_t *info = &feature_infos[i];

   unsigned int bits_needed;

   if ((info->flags & F_GLOBAL) && info->max_value == 1)
     /* Uses the global bit */
     bits_needed = 0;
   else
     /* Limit bits per feature. */
     bits_needed = hb_min (HB_OT_MAP_MAX_BITS, hb_bit_storage (info->max_value));

   if (!info->max_value || next_bit + bits_needed >= global_bit_shift)
     continue; /* Feature disabled, or not enough bits. */

   bool found = false;
   unsigned int feature_index[2];
   for (unsigned int table_index = 0; table_index < 2; table_index++)
   {
     if (required_feature_tag[table_index] == info->tag)
required_feature_stage[table_index] = info->stage[table_index];

     hb_codepoint_t *index;
     if (feature_indices[table_index].has (info->tag, &index))
     {
       feature_index[table_index] = *index;
       found = true;
     }
     else
       feature_index[table_index] = HB_OT_LAYOUT_NO_FEATURE_INDEX;
   }
   if (!found && (info->flags & F_GLOBAL_SEARCH))
   {
     for (unsigned int table_index = 0; table_index < 2; table_index++)
     {
found |= (bool) hb_ot_layout_table_find_feature (face,
						 table_tags[table_index],
						 info->tag,
						 &feature_index[table_index]);
     }
   }
   if (!found && !(info->flags & F_HAS_FALLBACK))
     continue;


   hb_ot_map_t::feature_map_t *map = m.features.push ();

   map->tag = info->tag;
   map->index[0] = feature_index[0];
   map->index[1] = feature_index[1];
   map->stage[0] = info->stage[0];
   map->stage[1] = info->stage[1];
   map->auto_zwnj = !(info->flags & F_MANUAL_ZWNJ);
   map->auto_zwj = !(info->flags & F_MANUAL_ZWJ);
   map->random = !!(info->flags & F_RANDOM);
   map->per_syllable = !!(info->flags & F_PER_SYLLABLE);
   if ((info->flags & F_GLOBAL) && info->max_value == 1) {
     /* Uses the global bit */
     map->shift = global_bit_shift;
     map->mask = global_bit_mask;
   } else {
     map->shift = next_bit;
     map->mask = (1u << (next_bit + bits_needed)) - (1u << next_bit);
     next_bit += bits_needed;
     m.global_mask |= (info->default_value << map->shift) & map->mask;
   }
   map->_1_mask = (1u << map->shift) & map->mask;
   map->needs_fallback = !found;
 }
 //feature_infos.shrink (0); /* Done with these */
 if (is_simple)
   m.features.qsort ();

 add_gsub_pause (nullptr);
 add_gpos_pause (nullptr);

 for (unsigned int table_index = 0; table_index < 2; table_index++)
 {
   /* Collect lookup indices for features */
   auto &lookups = m.lookups[table_index];

   unsigned int stage_index = 0;
   unsigned int last_num_lookups = 0;
   for (unsigned stage = 0; stage < current_stage[table_index]; stage++)
   {
     if (required_feature_index[table_index] != HB_OT_LAYOUT_NO_FEATURE_INDEX &&
  required_feature_stage[table_index] == stage)
add_lookups (m, table_index,
	     required_feature_index[table_index],
	     key.variations_index[table_index],
	     global_bit_mask);

     for (auto &feature : m.features)
     {
if (feature.stage[table_index] == stage)
  add_lookups (m, table_index,
	       feature.index[table_index],
	       key.variations_index[table_index],
	       feature.mask,
	       feature.auto_zwnj,
	       feature.auto_zwj,
	       feature.random,
	       feature.per_syllable,
	       feature.tag);
     }

     /* Sort lookups and merge duplicates */
     if (last_num_lookups + 1 < lookups.length)
     {
lookups.as_array ().sub_array (last_num_lookups, lookups.length - last_num_lookups).qsort ();

unsigned int j = last_num_lookups;
for (unsigned int i = j + 1; i < lookups.length; i++)
  if (lookups.arrayZ[i].index != lookups.arrayZ[j].index)
    lookups.arrayZ[++j] = lookups.arrayZ[i];
  else
  {
    lookups.arrayZ[j].mask |= lookups.arrayZ[i].mask;
    lookups.arrayZ[j].auto_zwnj &= lookups.arrayZ[i].auto_zwnj;
    lookups.arrayZ[j].auto_zwj &= lookups.arrayZ[i].auto_zwj;
  }
lookups.shrink (j + 1);
     }

     last_num_lookups = lookups.length;

     if (stage_index < stages[table_index].length && stages[table_index][stage_index].index == stage) {
hb_ot_map_t::stage_map_t *stage_map = m.stages[table_index].push ();
stage_map->last_lookup = last_num_lookups;
stage_map->pause_func = stages[table_index][stage_index].pause_func;

stage_index++;
     }
   }
 }
}

unsigned int hb_ot_map_t::get_feature_tags (unsigned int start_offset, unsigned int *tag_count, hb_tag_t *tags) const
{
 if (tag_count)
 {
   auto sub_features = features.as_array ().sub_array (start_offset, tag_count);
   if (tags)
   {
     for (unsigned int i = 0; i < sub_features.length; i++)
       tags[i] = sub_features[i].tag;
   }
 }

 return features.length;
}

#endif