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-private.hh"
  30
  31 #include "hb-ot-layout-private.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].len; 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   face = face_;
  47   props = *props_;
  48
  49
  50   /* Fetch script/language indices for GSUB/GPOS.  We need these later to skip
  51    * features not available in either table and not waste precious bits for them. */
  52
  53   hb_tag_t script_tags[3] = {HB_TAG_NONE, HB_TAG_NONE, HB_TAG_NONE};
  54   hb_tag_t language_tag;
  55
  56   hb_ot_tags_from_script (props.script, &script_tags[0], &script_tags[1]);
  57   language_tag = hb_ot_tag_from_language (props.language);
  58
  59   for (unsigned int table_index = 0; table_index < 2; table_index++) {
  60     hb_tag_t table_tag = table_tags[table_index];
  61     found_script[table_index] = (bool) hb_ot_layout_table_choose_script (face, table_tag, script_tags, &script_index[table_index], &chosen_script[table_index]);
  62     hb_ot_layout_script_find_language (face, table_tag, script_index[table_index], language_tag, &language_index[table_index]);
  63   }
  64 }
  65
  66 void hb_ot_map_builder_t::add_feature (hb_tag_t tag, unsigned int value,
  67                                        hb_ot_map_feature_flags_t flags)
  68 {
  69   feature_info_t *info = feature_infos.push();
  70   if (unlikely (!info)) return;
  71   if (unlikely (!tag)) return;
  72   info->tag = tag;
  73   info->seq = feature_infos.len;
  74   info->max_value = value;
  75   info->flags = flags;
  76   info->default_value = (flags & F_GLOBAL) ? value : 0;
  77   info->stage[0] = current_stage[0];
  78   info->stage[1] = current_stage[1];
  79 }
  80
  81 void
  82 hb_ot_map_builder_t::add_lookups (hb_ot_map_t  &m,
  83                                   unsigned int  table_index,
  84                                   unsigned int  feature_index,
  85                                   unsigned int  variations_index,
  86                                   hb_mask_t     mask,
  87                                   bool          auto_zwnj,
  88                                   bool          auto_zwj)
  89 {
  90   unsigned int lookup_indices[32];
  91   unsigned int offset, len;
  92   unsigned int table_lookup_count;
  93
  94   table_lookup_count = hb_ot_layout_table_get_lookup_count (face, table_tags[table_index]);
  95
  96   offset = 0;
  97   do {
  98     len = ARRAY_LENGTH (lookup_indices);
  99     hb_ot_layout_feature_with_variations_get_lookups (face,
 100                                                       table_tags[table_index],
 101                                                       feature_index,
 102                                                       variations_index,
 103                                                       offset, &len,
 104                                                       lookup_indices);
 105
 106     for (unsigned int i = 0; i < len; i++)
 107     {
 108       if (lookup_indices[i] >= table_lookup_count)
 109         continue;
 110       hb_ot_map_t::lookup_map_t *lookup = m.lookups[table_index].push ();
 111       if (unlikely (!lookup))
 112         return;
 113       lookup->mask = mask;
 114       lookup->index = lookup_indices[i];
 115       lookup->auto_zwnj = auto_zwnj;
 116       lookup->auto_zwj = auto_zwj;
 117     }
 118
 119     offset += len;
 120   } while (len == ARRAY_LENGTH (lookup_indices));
 121 }
 122
 123
 124 void hb_ot_map_builder_t::add_pause (unsigned int table_index, hb_ot_map_t::pause_func_t pause_func)
 125 {
 126   stage_info_t *s = stages[table_index].push ();
 127   if (likely (s)) {
 128     s->index = current_stage[table_index];
 129     s->pause_func = pause_func;
 130   }
 131
 132   current_stage[table_index]++;
 133 }
 134
 135 void
 136 hb_ot_map_builder_t::compile (hb_ot_map_t  &m,
 137                               const int    *coords,
 138                               unsigned int  num_coords)
 139 {
 140   static_assert ((!(HB_GLYPH_FLAG_DEFINED & (HB_GLYPH_FLAG_DEFINED + 1))), "");
 141   unsigned int global_bit_mask = HB_GLYPH_FLAG_DEFINED + 1;
 142   unsigned int global_bit_shift = _hb_popcount (HB_GLYPH_FLAG_DEFINED);
 143
 144   m.global_mask = global_bit_mask;
 145
 146   unsigned int required_feature_index[2];
 147   hb_tag_t required_feature_tag[2];
 148   /* We default to applying required feature in stage 0.  If the required
 149    * feature has a tag that is known to the shaper, we apply required feature
 150    * in the stage for that tag.
 151    */
 152   unsigned int required_feature_stage[2] = {0, 0};
 153
 154   for (unsigned int table_index = 0; table_index < 2; table_index++)
 155   {
 156     m.chosen_script[table_index] = chosen_script[table_index];
 157     m.found_script[table_index] = found_script[table_index];
 158
 159     hb_ot_layout_language_get_required_feature (face,
 160                                                 table_tags[table_index],
 161                                                 script_index[table_index],
 162                                                 language_index[table_index],
 163                                                 &required_feature_index[table_index],
 164                                                 &required_feature_tag[table_index]);
 165   }
 166
 167   if (!feature_infos.len)
 168     return;
 169
 170   /* Sort features and merge duplicates */
 171   {
 172     feature_infos.qsort ();
 173     unsigned int j = 0;
 174     for (unsigned int i = 1; i < feature_infos.len; i++)
 175       if (feature_infos[i].tag != feature_infos[j].tag)
 176         feature_infos[++j] = feature_infos[i];
 177       else {
 178         if (feature_infos[i].flags & F_GLOBAL) {
 179           feature_infos[j].flags |= F_GLOBAL;
 180           feature_infos[j].max_value = feature_infos[i].max_value;
 181           feature_infos[j].default_value = feature_infos[i].default_value;
 182         } else {
 183           feature_infos[j].flags &= ~F_GLOBAL;
 184           feature_infos[j].max_value = MAX (feature_infos[j].max_value, feature_infos[i].max_value);
 185           /* Inherit default_value from j */
 186         }
 187         feature_infos[j].flags |= (feature_infos[i].flags & F_HAS_FALLBACK);
 188         feature_infos[j].stage[0] = MIN (feature_infos[j].stage[0], feature_infos[i].stage[0]);
 189         feature_infos[j].stage[1] = MIN (feature_infos[j].stage[1], feature_infos[i].stage[1]);
 190       }
 191     feature_infos.shrink (j + 1);
 192   }
 193
 194
 195   /* Allocate bits now */
 196   unsigned int next_bit = global_bit_shift + 1;
 197
 198   for (unsigned int i = 0; i < feature_infos.len; i++)
 199   {
 200     const feature_info_t *info = &feature_infos[i];
 201
 202     unsigned int bits_needed;
 203
 204     if ((info->flags & F_GLOBAL) && info->max_value == 1)
 205       /* Uses the global bit */
 206       bits_needed = 0;
 207     else
 208       /* Limit to 8 bits per feature. */
 209       bits_needed = MIN(8u, _hb_bit_storage (info->max_value));
 210
 211     if (!info->max_value || next_bit + bits_needed > 8 * sizeof (hb_mask_t))
 212       continue; /* Feature disabled, or not enough bits. */
 213
 214
 215     hb_bool_t found = false;
 216     unsigned int feature_index[2];
 217     for (unsigned int table_index = 0; table_index < 2; table_index++)
 218     {
 219       if (required_feature_tag[table_index] == info->tag)
 220         required_feature_stage[table_index] = info->stage[table_index];
 221
 222       found |= hb_ot_layout_language_find_feature (face,
 223                                                    table_tags[table_index],
 224                                                    script_index[table_index],
 225                                                    language_index[table_index],
 226                                                    info->tag,
 227                                                    &feature_index[table_index]);
 228     }
 229     if (!found && (info->flags & F_GLOBAL_SEARCH))
 230     {
 231       for (unsigned int table_index = 0; table_index < 2; table_index++)
 232       {
 233         found |= hb_ot_layout_table_find_feature (face,
 234                                                   table_tags[table_index],
 235                                                   info->tag,
 236                                                   &feature_index[table_index]);
 237       }
 238     }
 239     if (!found && !(info->flags & F_HAS_FALLBACK))
 240       continue;
 241
 242
 243     hb_ot_map_t::feature_map_t *map = m.features.push ();
 244     if (unlikely (!map))
 245       break;
 246
 247     map->tag = info->tag;
 248     map->index[0] = feature_index[0];
 249     map->index[1] = feature_index[1];
 250     map->stage[0] = info->stage[0];
 251     map->stage[1] = info->stage[1];
 252     map->auto_zwnj = !(info->flags & F_MANUAL_ZWNJ);
 253     map->auto_zwj = !(info->flags & F_MANUAL_ZWJ);
 254     if ((info->flags & F_GLOBAL) && info->max_value == 1) {
 255       /* Uses the global bit */
 256       map->shift = global_bit_shift;
 257       map->mask = global_bit_mask;
 258     } else {
 259       map->shift = next_bit;
 260       map->mask = (1u << (next_bit + bits_needed)) - (1u << next_bit);
 261       next_bit += bits_needed;
 262       m.global_mask |= (info->default_value << map->shift) & map->mask;
 263     }
 264     map->_1_mask = (1u << map->shift) & map->mask;
 265     map->needs_fallback = !found;
 266
 267   }
 268   feature_infos.shrink (0); /* Done with these */
 269
 270
 271   add_gsub_pause (nullptr);
 272   add_gpos_pause (nullptr);
 273
 274   for (unsigned int table_index = 0; table_index < 2; table_index++)
 275   {
 276     /* Collect lookup indices for features */
 277
 278     unsigned int variations_index;
 279     hb_ot_layout_table_find_feature_variations (face,
 280                                                 table_tags[table_index],
 281                                                 coords,
 282                                                 num_coords,
 283                                                 &variations_index);
 284
 285     unsigned int stage_index = 0;
 286     unsigned int last_num_lookups = 0;
 287     for (unsigned stage = 0; stage < current_stage[table_index]; stage++)
 288     {
 289       if (required_feature_index[table_index] != HB_OT_LAYOUT_NO_FEATURE_INDEX &&
 290           required_feature_stage[table_index] == stage)
 291         add_lookups (m, table_index,
 292                      required_feature_index[table_index],
 293                      variations_index,
 294                      global_bit_mask);
 295
 296       for (unsigned i = 0; i < m.features.len; i++)
 297         if (m.features[i].stage[table_index] == stage)
 298           add_lookups (m, table_index,
 299                        m.features[i].index[table_index],
 300                        variations_index,
 301                        m.features[i].mask,
 302                        m.features[i].auto_zwnj,
 303                        m.features[i].auto_zwj);
 304
 305       /* Sort lookups and merge duplicates */
 306       if (last_num_lookups < m.lookups[table_index].len)
 307       {
 308         m.lookups[table_index].qsort (last_num_lookups, m.lookups[table_index].len);
 309
 310         unsigned int j = last_num_lookups;
 311         for (unsigned int i = j + 1; i < m.lookups[table_index].len; 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].len;
 324
 325       if (stage_index < stages[table_index].len && stages[table_index][stage_index].index == stage) {
 326         hb_ot_map_t::stage_map_t *stage_map = m.stages[table_index].push ();
 327         if (likely (stage_map)) {
 328           stage_map->last_lookup = last_num_lookups;
 329           stage_map->pause_func = stages[table_index][stage_index].pause_func;
 330         }
 331
 332         stage_index++;
 333       }
 334     }
 335   }
 336 }