src/hb-ot-map.cc

   1 /*
   2  * Copyright © 2009,2010  Red Hat, Inc.
   3  * Copyright © 2010,2011,2013  Google, Inc.
   4  *
   5  *  This is part of HarfBuzz, a text shaping library.
   6  *
   7  * Permission is hereby granted, without written agreement and without
   8  * license or royalty fees, to use, copy, modify, and distribute this
   9  * software and its documentation for any purpose, provided that the
  10  * above copyright notice and the following two paragraphs appear in
  11  * all copies of this software.
  12  *
  13  * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
  14  * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
  15  * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
  16  * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
  17  * DAMAGE.
  18  *
  19  * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
  20  * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
  21  * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
  22  * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
  23  * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
  24  *
  25  * Red Hat Author(s): Behdad Esfahbod
  26  * Google Author(s): Behdad Esfahbod
  27  */
  28
  29 #include "hb.hh"
  30
  31 #ifndef HB_NO_OT_SHAPE
  32
  33 #include "hb-ot-map.hh"
  34 #include "hb-ot-shape.hh"
  35 #include "hb-ot-layout.hh"
  36
  37
  38 void hb_ot_map_t::collect_lookups (unsigned int table_index, hb_set_t *lookups_out) const
  39 {
  40   for (unsigned int i = 0; i < lookups[table_index].length; i++)
  41     lookups_out->add (lookups[table_index][i].index);
  42 }
  43
  44
  45 hb_ot_map_builder_t::hb_ot_map_builder_t (hb_face_t *face_,
  46                                           const hb_segment_properties_t &props_)
  47 {
  48   hb_memset (this, 0, sizeof (*this));
  49
  50   feature_infos.init ();
  51   for (unsigned int table_index = 0; table_index < 2; table_index++)
  52     stages[table_index].init ();
  53
  54   face = face_;
  55   props = props_;
  56
  57   /* Fetch script/language indices for GSUB/GPOS.  We need these later to skip
  58    * features not available in either table and not waste precious bits for them. */
  59
  60   unsigned int script_count = HB_OT_MAX_TAGS_PER_SCRIPT;
  61   unsigned int language_count = HB_OT_MAX_TAGS_PER_LANGUAGE;
  62   hb_tag_t script_tags[HB_OT_MAX_TAGS_PER_SCRIPT];
  63   hb_tag_t language_tags[HB_OT_MAX_TAGS_PER_LANGUAGE];
  64
  65   hb_ot_tags_from_script_and_language (props.script,
  66                                        props.language,
  67                                        &script_count,
  68                                        script_tags,
  69                                        &language_count,
  70                                        language_tags);
  71
  72   for (unsigned int table_index = 0; table_index < 2; table_index++)
  73   {
  74     hb_tag_t table_tag = table_tags[table_index];
  75     found_script[table_index] = (bool) hb_ot_layout_table_select_script (face,
  76                                                                          table_tag,
  77                                                                          script_count,
  78                                                                          script_tags,
  79                                                                          &script_index[table_index],
  80                                                                          &chosen_script[table_index]);
  81     hb_ot_layout_script_select_language (face,
  82                                          table_tag,
  83                                          script_index[table_index],
  84                                          language_count,
  85                                          language_tags,
  86                                          &language_index[table_index]);
  87   }
  88 }
  89
  90 hb_ot_map_builder_t::~hb_ot_map_builder_t ()
  91 {
  92   feature_infos.fini ();
  93   for (unsigned int table_index = 0; table_index < 2; table_index++)
  94     stages[table_index].fini ();
  95 }
  96
  97 void hb_ot_map_builder_t::add_feature (hb_tag_t tag,
  98                                        hb_ot_map_feature_flags_t flags,
  99                                        unsigned int value)
 100 {
 101   if (unlikely (!tag)) return;
 102   feature_info_t *info = feature_infos.push();
 103   info->tag = tag;
 104   info->seq = feature_infos.length;
 105   info->max_value = value;
 106   info->flags = flags;
 107   info->default_value = (flags & F_GLOBAL) ? value : 0;
 108   info->stage[0] = current_stage[0];
 109   info->stage[1] = current_stage[1];
 110 }
 111
 112 bool hb_ot_map_builder_t::has_feature (hb_tag_t tag)
 113 {
 114   for (unsigned int table_index = 0; table_index < 2; table_index++)
 115   {
 116     if (hb_ot_layout_language_find_feature (face,
 117                                             table_tags[table_index],
 118                                             script_index[table_index],
 119                                             language_index[table_index],
 120                                             tag,
 121                                             nullptr))
 122       return true;
 123   }
 124   return false;
 125 }
 126
 127 void
 128 hb_ot_map_builder_t::add_lookups (hb_ot_map_t  &m,
 129                                   unsigned int  table_index,
 130                                   unsigned int  feature_index,
 131                                   unsigned int  variations_index,
 132                                   hb_mask_t     mask,
 133                                   bool          auto_zwnj,
 134                                   bool          auto_zwj,
 135                                   bool          random,
 136                                   bool          per_syllable,
 137                                   hb_tag_t      feature_tag)
 138 {
 139   unsigned int lookup_indices[32];
 140   unsigned int offset, len;
 141   unsigned int table_lookup_count;
 142
 143   table_lookup_count = hb_ot_layout_table_get_lookup_count (face, table_tags[table_index]);
 144
 145   offset = 0;
 146   do {
 147     len = ARRAY_LENGTH (lookup_indices);
 148     hb_ot_layout_feature_with_variations_get_lookups (face,
 149                                                       table_tags[table_index],
 150                                                       feature_index,
 151                                                       variations_index,
 152                                                       offset, &len,
 153                                                       lookup_indices);
 154
 155     for (unsigned int i = 0; i < len; i++)
 156     {
 157       if (lookup_indices[i] >= table_lookup_count)
 158         continue;
 159       hb_ot_map_t::lookup_map_t *lookup = m.lookups[table_index].push ();
 160       lookup->mask = mask;
 161       lookup->index = lookup_indices[i];
 162       lookup->auto_zwnj = auto_zwnj;
 163       lookup->auto_zwj = auto_zwj;
 164       lookup->random = random;
 165       lookup->per_syllable = per_syllable;
 166       lookup->feature_tag = feature_tag;
 167     }
 168
 169     offset += len;
 170   } while (len == ARRAY_LENGTH (lookup_indices));
 171 }
 172
 173
 174 void hb_ot_map_builder_t::add_pause (unsigned int table_index, hb_ot_map_t::pause_func_t pause_func)
 175 {
 176   stage_info_t *s = stages[table_index].push ();
 177   s->index = current_stage[table_index];
 178   s->pause_func = pause_func;
 179
 180   current_stage[table_index]++;
 181 }
 182
 183 void
 184 hb_ot_map_builder_t::compile (hb_ot_map_t                  &m,
 185                               const hb_ot_shape_plan_key_t &key)
 186 {
 187   unsigned int global_bit_shift = 8 * sizeof (hb_mask_t) - 1;
 188   unsigned int global_bit_mask = 1u << global_bit_shift;
 189
 190   m.global_mask = global_bit_mask;
 191
 192   unsigned int required_feature_index[2];
 193   hb_tag_t required_feature_tag[2];
 194   /* We default to applying required feature in stage 0.  If the required
 195    * feature has a tag that is known to the shaper, we apply required feature
 196    * in the stage for that tag.
 197    */
 198   unsigned int required_feature_stage[2] = {0, 0};
 199
 200   for (unsigned int table_index = 0; table_index < 2; table_index++)
 201   {
 202     m.chosen_script[table_index] = chosen_script[table_index];
 203     m.found_script[table_index] = found_script[table_index];
 204
 205     hb_ot_layout_language_get_required_feature (face,
 206                                                 table_tags[table_index],
 207                                                 script_index[table_index],
 208                                                 language_index[table_index],
 209                                                 &required_feature_index[table_index],
 210                                                 &required_feature_tag[table_index]);
 211   }
 212
 213   /* Sort features and merge duplicates */
 214   if (feature_infos.length)
 215   {
 216     if (!is_simple)
 217       feature_infos.qsort ();
 218     auto *f = feature_infos.arrayZ;
 219     unsigned int j = 0;
 220     unsigned count = feature_infos.length;
 221     for (unsigned int i = 1; i < count; i++)
 222       if (f[i].tag != f[j].tag)
 223         f[++j] = f[i];
 224       else {
 225         if (f[i].flags & F_GLOBAL) {
 226           f[j].flags |= F_GLOBAL;
 227           f[j].max_value = f[i].max_value;
 228           f[j].default_value = f[i].default_value;
 229         } else {
 230           if (f[j].flags & F_GLOBAL)
 231             f[j].flags ^= F_GLOBAL;
 232           f[j].max_value = hb_max (f[j].max_value, f[i].max_value);
 233           /* Inherit default_value from j */
 234         }
 235         f[j].flags |= (f[i].flags & F_HAS_FALLBACK);
 236         f[j].stage[0] = hb_min (f[j].stage[0], f[i].stage[0]);
 237         f[j].stage[1] = hb_min (f[j].stage[1], f[i].stage[1]);
 238       }
 239     feature_infos.shrink (j + 1);
 240   }
 241
 242   hb_map_t feature_indices[2];
 243   for (unsigned int table_index = 0; table_index < 2; table_index++)
 244     hb_ot_layout_collect_features_map (face,
 245                                        table_tags[table_index],
 246                                        script_index[table_index],
 247                                        language_index[table_index],
 248                                        &feature_indices[table_index]);
 249
 250   /* Allocate bits now */
 251   static_assert ((!(HB_GLYPH_FLAG_DEFINED & (HB_GLYPH_FLAG_DEFINED + 1))), "");
 252   unsigned int next_bit = hb_popcount (HB_GLYPH_FLAG_DEFINED) + 1;
 253
 254   unsigned count = feature_infos.length;
 255   for (unsigned int i = 0; i < count; i++)
 256   {
 257     const feature_info_t *info = &feature_infos[i];
 258
 259     unsigned int bits_needed;
 260
 261     if ((info->flags & F_GLOBAL) && info->max_value == 1)
 262       /* Uses the global bit */
 263       bits_needed = 0;
 264     else
 265       /* Limit bits per feature. */
 266       bits_needed = hb_min (HB_OT_MAP_MAX_BITS, hb_bit_storage (info->max_value));
 267
 268     if (!info->max_value || next_bit + bits_needed >= global_bit_shift)
 269       continue; /* Feature disabled, or not enough bits. */
 270
 271     bool found = false;
 272     unsigned int feature_index[2];
 273     for (unsigned int table_index = 0; table_index < 2; table_index++)
 274     {
 275       if (required_feature_tag[table_index] == info->tag)
 276         required_feature_stage[table_index] = info->stage[table_index];
 277
 278       hb_codepoint_t *index;
 279       if (feature_indices[table_index].has (info->tag, &index))
 280       {
 281         feature_index[table_index] = *index;
 282         found = true;
 283       }
 284       else
 285         feature_index[table_index] = HB_OT_LAYOUT_NO_FEATURE_INDEX;
 286     }
 287     if (!found && (info->flags & F_GLOBAL_SEARCH))
 288     {
 289       for (unsigned int table_index = 0; table_index < 2; table_index++)
 290       {
 291         found |= (bool) hb_ot_layout_table_find_feature (face,
 292                                                          table_tags[table_index],
 293                                                          info->tag,
 294                                                          &feature_index[table_index]);
 295       }
 296     }
 297     if (!found && !(info->flags & F_HAS_FALLBACK))
 298       continue;
 299
 300
 301     hb_ot_map_t::feature_map_t *map = m.features.push ();
 302
 303     map->tag = info->tag;
 304     map->index[0] = feature_index[0];
 305     map->index[1] = feature_index[1];
 306     map->stage[0] = info->stage[0];
 307     map->stage[1] = info->stage[1];
 308     map->auto_zwnj = !(info->flags & F_MANUAL_ZWNJ);
 309     map->auto_zwj = !(info->flags & F_MANUAL_ZWJ);
 310     map->random = !!(info->flags & F_RANDOM);
 311     map->per_syllable = !!(info->flags & F_PER_SYLLABLE);
 312     if ((info->flags & F_GLOBAL) && info->max_value == 1) {
 313       /* Uses the global bit */
 314       map->shift = global_bit_shift;
 315       map->mask = global_bit_mask;
 316     } else {
 317       map->shift = next_bit;
 318       map->mask = (1u << (next_bit + bits_needed)) - (1u << next_bit);
 319       next_bit += bits_needed;
 320       m.global_mask |= (info->default_value << map->shift) & map->mask;
 321     }
 322     map->_1_mask = (1u << map->shift) & map->mask;
 323     map->needs_fallback = !found;
 324   }
 325   //feature_infos.shrink (0); /* Done with these */
 326   if (is_simple)
 327     m.features.qsort ();
 328
 329   add_gsub_pause (nullptr);
 330   add_gpos_pause (nullptr);
 331
 332   for (unsigned int table_index = 0; table_index < 2; table_index++)
 333   {
 334     /* Collect lookup indices for features */
 335     auto &lookups = m.lookups[table_index];
 336
 337     unsigned int stage_index = 0;
 338     unsigned int last_num_lookups = 0;
 339     for (unsigned stage = 0; stage < current_stage[table_index]; stage++)
 340     {
 341       if (required_feature_index[table_index] != HB_OT_LAYOUT_NO_FEATURE_INDEX &&
 342           required_feature_stage[table_index] == stage)
 343         add_lookups (m, table_index,
 344                      required_feature_index[table_index],
 345                      key.variations_index[table_index],
 346                      global_bit_mask);
 347
 348       for (auto &feature : m.features)
 349       {
 350         if (feature.stage[table_index] == stage)
 351           add_lookups (m, table_index,
 352                        feature.index[table_index],
 353                        key.variations_index[table_index],
 354                        feature.mask,
 355                        feature.auto_zwnj,
 356                        feature.auto_zwj,
 357                        feature.random,
 358                        feature.per_syllable,
 359                        feature.tag);
 360       }
 361
 362       /* Sort lookups and merge duplicates */
 363       if (last_num_lookups + 1 < lookups.length)
 364       {
 365         lookups.as_array ().sub_array (last_num_lookups, lookups.length - last_num_lookups).qsort ();
 366
 367         unsigned int j = last_num_lookups;
 368         for (unsigned int i = j + 1; i < lookups.length; i++)
 369           if (lookups.arrayZ[i].index != lookups.arrayZ[j].index)
 370             lookups.arrayZ[++j] = lookups.arrayZ[i];
 371           else
 372           {
 373             lookups.arrayZ[j].mask |= lookups.arrayZ[i].mask;
 374             lookups.arrayZ[j].auto_zwnj &= lookups.arrayZ[i].auto_zwnj;
 375             lookups.arrayZ[j].auto_zwj &= lookups.arrayZ[i].auto_zwj;
 376           }
 377         lookups.shrink (j + 1);
 378       }
 379
 380       last_num_lookups = lookups.length;
 381
 382       if (stage_index < stages[table_index].length && stages[table_index][stage_index].index == stage) {
 383         hb_ot_map_t::stage_map_t *stage_map = m.stages[table_index].push ();
 384         stage_map->last_lookup = last_num_lookups;
 385         stage_map->pause_func = stages[table_index][stage_index].pause_func;
 386
 387         stage_index++;
 388       }
 389     }
 390   }
 391 }
 392
 393
 394 #endif