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-ot-map.hh"
  30 #include "hb-ot-shape.hh"
  31 #include "hb-ot-layout.hh"
  32
  33
  34 void hb_ot_map_t::collect_lookups (unsigned int table_index, hb_set_t *lookups_out) const
  35 {
  36   for (unsigned int i = 0; i < lookups[table_index].length; i++)
  37     hb_set_add (lookups_out, lookups[table_index][i].index);
  38 }
  39
  40
  41 hb_ot_map_builder_t::hb_ot_map_builder_t (hb_face_t *face_,
  42                                           const hb_segment_properties_t *props_)
  43 {
  44   memset (this, 0, sizeof (*this));
  45
  46   feature_infos.init ();
  47   for (unsigned int table_index = 0; table_index < 2; table_index++)
  48     stages[table_index].init ();
  49
  50   face = face_;
  51   props = *props_;
  52
  53
  54   /* Fetch script/language indices for GSUB/GPOS.  We need these later to skip
  55    * features not available in either table and not waste precious bits for them. */
  56
  57   unsigned int script_count = HB_OT_MAX_TAGS_PER_SCRIPT;
  58   unsigned int language_count = HB_OT_MAX_TAGS_PER_LANGUAGE;
  59   hb_tag_t script_tags[HB_OT_MAX_TAGS_PER_SCRIPT];
  60   hb_tag_t language_tags[HB_OT_MAX_TAGS_PER_LANGUAGE];
  61
  62   hb_ot_tags_from_script_and_language (props.script, props.language, &script_count, script_tags, &language_count, language_tags);
  63
  64   for (unsigned int table_index = 0; table_index < 2; table_index++) {
  65     hb_tag_t table_tag = table_tags[table_index];
  66     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]);
  67     hb_ot_layout_script_select_language (face, table_tag, script_index[table_index], language_count, language_tags, &language_index[table_index]);
  68   }
  69 }
  70
  71 hb_ot_map_builder_t::~hb_ot_map_builder_t ()
  72 {
  73   feature_infos.fini ();
  74   for (unsigned int table_index = 0; table_index < 2; table_index++)
  75     stages[table_index].fini ();
  76 }
  77
  78 void hb_ot_map_builder_t::add_feature (hb_tag_t tag,
  79                                        hb_ot_map_feature_flags_t flags,
  80                                        unsigned int value)
  81 {
  82   if (unlikely (!tag)) return;
  83   feature_info_t *info = feature_infos.push();
  84   info->tag = tag;
  85   info->seq = feature_infos.length;
  86   info->max_value = value;
  87   info->flags = flags;
  88   info->default_value = (flags & F_GLOBAL) ? value : 0;
  89   info->stage[0] = current_stage[0];
  90   info->stage[1] = current_stage[1];
  91 }
  92
  93 void
  94 hb_ot_map_builder_t::add_lookups (hb_ot_map_t  &m,
  95                                   unsigned int  table_index,
  96                                   unsigned int  feature_index,
  97                                   unsigned int  variations_index,
  98                                   hb_mask_t     mask,
  99                                   bool          auto_zwnj,
 100                                   bool          auto_zwj,
 101                                   bool          random)
 102 {
 103   unsigned int lookup_indices[32];
 104   unsigned int offset, len;
 105   unsigned int table_lookup_count;
 106
 107   table_lookup_count = hb_ot_layout_table_get_lookup_count (face, table_tags[table_index]);
 108
 109   offset = 0;
 110   do {
 111     len = ARRAY_LENGTH (lookup_indices);
 112     hb_ot_layout_feature_with_variations_get_lookups (face,
 113                                                       table_tags[table_index],
 114                                                       feature_index,
 115                                                       variations_index,
 116                                                       offset, &len,
 117                                                       lookup_indices);
 118
 119     for (unsigned int i = 0; i < len; i++)
 120     {
 121       if (lookup_indices[i] >= table_lookup_count)
 122         continue;
 123       hb_ot_map_t::lookup_map_t *lookup = m.lookups[table_index].push ();
 124       lookup->mask = mask;
 125       lookup->index = lookup_indices[i];
 126       lookup->auto_zwnj = auto_zwnj;
 127       lookup->auto_zwj = auto_zwj;
 128       lookup->random = random;
 129     }
 130
 131     offset += len;
 132   } while (len == ARRAY_LENGTH (lookup_indices));
 133 }
 134
 135
 136 void hb_ot_map_builder_t::add_pause (unsigned int table_index, hb_ot_map_t::pause_func_t pause_func)
 137 {
 138   stage_info_t *s = stages[table_index].push ();
 139   s->index = current_stage[table_index];
 140   s->pause_func = pause_func;
 141
 142   current_stage[table_index]++;
 143 }
 144
 145 void
 146 hb_ot_map_builder_t::compile (hb_ot_map_t                  &m,
 147                               const hb_ot_shape_plan_key_t &key)
 148 {
 149   static_assert ((!(HB_GLYPH_FLAG_DEFINED & (HB_GLYPH_FLAG_DEFINED + 1))), "");
 150   unsigned int global_bit_mask = HB_GLYPH_FLAG_DEFINED + 1;
 151   unsigned int global_bit_shift = hb_popcount (HB_GLYPH_FLAG_DEFINED);
 152
 153   m.global_mask = global_bit_mask;
 154
 155   unsigned int required_feature_index[2];
 156   hb_tag_t required_feature_tag[2];
 157   /* We default to applying required feature in stage 0.  If the required
 158    * feature has a tag that is known to the shaper, we apply required feature
 159    * in the stage for that tag.
 160    */
 161   unsigned int required_feature_stage[2] = {0, 0};
 162
 163   for (unsigned int table_index = 0; table_index < 2; table_index++)
 164   {
 165     m.chosen_script[table_index] = chosen_script[table_index];
 166     m.found_script[table_index] = found_script[table_index];
 167
 168     hb_ot_layout_language_get_required_feature (face,
 169                                                 table_tags[table_index],
 170                                                 script_index[table_index],
 171                                                 language_index[table_index],
 172                                                 &required_feature_index[table_index],
 173                                                 &required_feature_tag[table_index]);
 174   }
 175
 176   /* Sort features and merge duplicates */
 177   if (feature_infos.length)
 178   {
 179     feature_infos.qsort ();
 180     unsigned int j = 0;
 181     for (unsigned int i = 1; i < feature_infos.length; i++)
 182       if (feature_infos[i].tag != feature_infos[j].tag)
 183         feature_infos[++j] = feature_infos[i];
 184       else {
 185         if (feature_infos[i].flags & F_GLOBAL) {
 186           feature_infos[j].flags |= F_GLOBAL;
 187           feature_infos[j].max_value = feature_infos[i].max_value;
 188           feature_infos[j].default_value = feature_infos[i].default_value;
 189         } else {
 190           feature_infos[j].flags &= ~F_GLOBAL;
 191           feature_infos[j].max_value = MAX (feature_infos[j].max_value, feature_infos[i].max_value);
 192           /* Inherit default_value from j */
 193         }
 194         feature_infos[j].flags |= (feature_infos[i].flags & F_HAS_FALLBACK);
 195         feature_infos[j].stage[0] = MIN (feature_infos[j].stage[0], feature_infos[i].stage[0]);
 196         feature_infos[j].stage[1] = MIN (feature_infos[j].stage[1], feature_infos[i].stage[1]);
 197       }
 198     feature_infos.shrink (j + 1);
 199   }
 200
 201
 202   /* Allocate bits now */
 203   unsigned int next_bit = global_bit_shift + 1;
 204
 205   for (unsigned int i = 0; i < feature_infos.length; i++)
 206   {
 207     const feature_info_t *info = &feature_infos[i];
 208
 209     unsigned int bits_needed;
 210
 211     if ((info->flags & F_GLOBAL) && info->max_value == 1)
 212       /* Uses the global bit */
 213       bits_needed = 0;
 214     else
 215       /* Limit bits per feature. */
 216       bits_needed = MIN(HB_OT_MAP_MAX_BITS, hb_bit_storage (info->max_value));
 217
 218     if (!info->max_value || next_bit + bits_needed > 8 * sizeof (hb_mask_t))
 219       continue; /* Feature disabled, or not enough bits. */
 220
 221
 222     hb_bool_t found = false;
 223     unsigned int feature_index[2];
 224     for (unsigned int table_index = 0; table_index < 2; table_index++)
 225     {
 226       if (required_feature_tag[table_index] == info->tag)
 227         required_feature_stage[table_index] = info->stage[table_index];
 228
 229       found |= hb_ot_layout_language_find_feature (face,
 230                                                    table_tags[table_index],
 231                                                    script_index[table_index],
 232                                                    language_index[table_index],
 233                                                    info->tag,
 234                                                    &feature_index[table_index]);
 235     }
 236     if (!found && (info->flags & F_GLOBAL_SEARCH))
 237     {
 238       for (unsigned int table_index = 0; table_index < 2; table_index++)
 239       {
 240         found |= hb_ot_layout_table_find_feature (face,
 241                                                   table_tags[table_index],
 242                                                   info->tag,
 243                                                   &feature_index[table_index]);
 244       }
 245     }
 246     if (!found && !(info->flags & F_HAS_FALLBACK))
 247       continue;
 248
 249
 250     hb_ot_map_t::feature_map_t *map = m.features.push ();
 251
 252     map->tag = info->tag;
 253     map->index[0] = feature_index[0];
 254     map->index[1] = feature_index[1];
 255     map->stage[0] = info->stage[0];
 256     map->stage[1] = info->stage[1];
 257     map->auto_zwnj = !(info->flags & F_MANUAL_ZWNJ);
 258     map->auto_zwj = !(info->flags & F_MANUAL_ZWJ);
 259     map->random = !!(info->flags & F_RANDOM);
 260     if ((info->flags & F_GLOBAL) && info->max_value == 1) {
 261       /* Uses the global bit */
 262       map->shift = global_bit_shift;
 263       map->mask = global_bit_mask;
 264     } else {
 265       map->shift = next_bit;
 266       map->mask = (1u << (next_bit + bits_needed)) - (1u << next_bit);
 267       next_bit += bits_needed;
 268       m.global_mask |= (info->default_value << map->shift) & map->mask;
 269     }
 270     map->_1_mask = (1u << map->shift) & map->mask;
 271     map->needs_fallback = !found;
 272
 273   }
 274   feature_infos.shrink (0); /* Done with these */
 275
 276
 277   add_gsub_pause (nullptr);
 278   add_gpos_pause (nullptr);
 279
 280   for (unsigned int table_index = 0; table_index < 2; table_index++)
 281   {
 282     /* Collect lookup indices for features */
 283
 284     unsigned int stage_index = 0;
 285     unsigned int last_num_lookups = 0;
 286     for (unsigned stage = 0; stage < current_stage[table_index]; stage++)
 287     {
 288       if (required_feature_index[table_index] != HB_OT_LAYOUT_NO_FEATURE_INDEX &&
 289           required_feature_stage[table_index] == stage)
 290         add_lookups (m, table_index,
 291                      required_feature_index[table_index],
 292                      key.variations_index[table_index],
 293                      global_bit_mask);
 294
 295       for (unsigned i = 0; i < m.features.length; i++)
 296         if (m.features[i].stage[table_index] == stage)
 297           add_lookups (m, table_index,
 298                        m.features[i].index[table_index],
 299                        key.variations_index[table_index],
 300                        m.features[i].mask,
 301                        m.features[i].auto_zwnj,
 302                        m.features[i].auto_zwj,
 303                        m.features[i].random);
 304
 305       /* Sort lookups and merge duplicates */
 306       if (last_num_lookups < m.lookups[table_index].length)
 307       {
 308         m.lookups[table_index].qsort (last_num_lookups, m.lookups[table_index].length);
 309
 310         unsigned int j = last_num_lookups;
 311         for (unsigned int i = j + 1; i < m.lookups[table_index].length; i++)
 312           if (m.lookups[table_index][i].index != m.lookups[table_index][j].index)
 313             m.lookups[table_index][++j] = m.lookups[table_index][i];
 314           else
 315           {
 316             m.lookups[table_index][j].mask |= m.lookups[table_index][i].mask;
 317             m.lookups[table_index][j].auto_zwnj &= m.lookups[table_index][i].auto_zwnj;
 318             m.lookups[table_index][j].auto_zwj &= m.lookups[table_index][i].auto_zwj;
 319           }
 320         m.lookups[table_index].shrink (j + 1);
 321       }
 322
 323       last_num_lookups = m.lookups[table_index].length;
 324
 325       if (stage_index < stages[table_index].length && stages[table_index][stage_index].index == stage) {
 326         hb_ot_map_t::stage_map_t *stage_map = m.stages[table_index].push ();
 327         stage_map->last_lookup = last_num_lookups;
 328         stage_map->pause_func = stages[table_index][stage_index].pause_func;
 329
 330         stage_index++;
 331       }
 332     }
 333   }
 334 }