third_party/harfbuzz-ng/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
  35 hb_ot_map_t::add_lookups (hb_face_t    *face,
  36                           unsigned int  table_index,
  37                           unsigned int  feature_index,
  38                           hb_mask_t     mask,
  39                           bool          auto_zwj)
  40 {
  41   unsigned int lookup_indices[32];
  42   unsigned int offset, len;
  43   unsigned int table_lookup_count;
  44
  45   table_lookup_count = hb_ot_layout_table_get_lookup_count (face, table_tags[table_index]);
  46
  47   offset = 0;
  48   do {
  49     len = ARRAY_LENGTH (lookup_indices);
  50     hb_ot_layout_feature_get_lookups (face,
  51                                       table_tags[table_index],
  52                                       feature_index,
  53                                       offset, &len,
  54                                       lookup_indices);
  55
  56     for (unsigned int i = 0; i < len; i++)
  57     {
  58       if (lookup_indices[i] >= table_lookup_count)
  59         continue;
  60       hb_ot_map_t::lookup_map_t *lookup = lookups[table_index].push ();
  61       if (unlikely (!lookup))
  62         return;
  63       lookup->mask = mask;
  64       lookup->index = lookup_indices[i];
  65       lookup->auto_zwj = auto_zwj;
  66     }
  67
  68     offset += len;
  69   } while (len == ARRAY_LENGTH (lookup_indices));
  70 }
  71
  72 hb_ot_map_builder_t::hb_ot_map_builder_t (hb_face_t *face_,
  73                                           const hb_segment_properties_t *props_)
  74 {
  75   memset (this, 0, sizeof (*this));
  76
  77   face = face_;
  78   props = *props_;
  79
  80
  81   /* Fetch script/language indices for GSUB/GPOS.  We need these later to skip
  82    * features not available in either table and not waste precious bits for them. */
  83
  84   hb_tag_t script_tags[3] = {HB_TAG_NONE, HB_TAG_NONE, HB_TAG_NONE};
  85   hb_tag_t language_tag;
  86
  87   hb_ot_tags_from_script (props.script, &script_tags[0], &script_tags[1]);
  88   language_tag = hb_ot_tag_from_language (props.language);
  89
  90   for (unsigned int table_index = 0; table_index < 2; table_index++) {
  91     hb_tag_t table_tag = table_tags[table_index];
  92     found_script[table_index] = hb_ot_layout_table_choose_script (face, table_tag, script_tags, &script_index[table_index], &chosen_script[table_index]);
  93     hb_ot_layout_script_find_language (face, table_tag, script_index[table_index], language_tag, &language_index[table_index]);
  94   }
  95 }
  96
  97 void hb_ot_map_builder_t::add_feature (hb_tag_t tag, unsigned int value,
  98                                        hb_ot_map_feature_flags_t flags)
  99 {
 100   feature_info_t *info = feature_infos.push();
 101   if (unlikely (!info)) return;
 102   if (unlikely (!tag)) return;
 103   info->tag = tag;
 104   info->seq = feature_infos.len;
 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
 113 void hb_ot_map_t::collect_lookups (unsigned int table_index, hb_set_t *lookups_out) const
 114 {
 115   for (unsigned int i = 0; i < lookups[table_index].len; i++)
 116     hb_set_add (lookups_out, lookups[table_index][i].index);
 117 }
 118
 119 void hb_ot_map_builder_t::add_pause (unsigned int table_index, hb_ot_map_t::pause_func_t pause_func)
 120 {
 121   stage_info_t *s = stages[table_index].push ();
 122   if (likely (s)) {
 123     s->index = current_stage[table_index];
 124     s->pause_func = pause_func;
 125   }
 126
 127   current_stage[table_index]++;
 128 }
 129
 130 void
 131 hb_ot_map_builder_t::compile (hb_ot_map_t &m)
 132 {
 133   m.global_mask = 1;
 134
 135   unsigned int required_feature_index[2];
 136   hb_tag_t required_feature_tag[2];
 137   /* We default to applying required feature in stage 0.  If the required
 138    * feature has a tag that is known to the shaper, we apply required feature
 139    * in the stage for that tag.
 140    */
 141   unsigned int required_feature_stage[2] = {0, 0};
 142
 143   for (unsigned int table_index = 0; table_index < 2; table_index++)
 144   {
 145     m.chosen_script[table_index] = chosen_script[table_index];
 146     m.found_script[table_index] = found_script[table_index];
 147
 148     hb_ot_layout_language_get_required_feature (face,
 149                                                 table_tags[table_index],
 150                                                 script_index[table_index],
 151                                                 language_index[table_index],
 152                                                 &required_feature_index[table_index],
 153                                                 &required_feature_tag[table_index]);
 154   }
 155
 156   if (!feature_infos.len)
 157     return;
 158
 159   /* Sort features and merge duplicates */
 160   {
 161     feature_infos.qsort ();
 162     unsigned int j = 0;
 163     for (unsigned int i = 1; i < feature_infos.len; i++)
 164       if (feature_infos[i].tag != feature_infos[j].tag)
 165         feature_infos[++j] = feature_infos[i];
 166       else {
 167         if (feature_infos[i].flags & F_GLOBAL) {
 168           feature_infos[j].flags |= F_GLOBAL;
 169           feature_infos[j].max_value = feature_infos[i].max_value;
 170           feature_infos[j].default_value = feature_infos[i].default_value;
 171         } else {
 172           feature_infos[j].flags &= ~F_GLOBAL;
 173           feature_infos[j].max_value = MAX (feature_infos[j].max_value, feature_infos[i].max_value);
 174           /* Inherit default_value from j */
 175         }
 176         feature_infos[j].flags |= (feature_infos[i].flags & F_HAS_FALLBACK);
 177         feature_infos[j].stage[0] = MIN (feature_infos[j].stage[0], feature_infos[i].stage[0]);
 178         feature_infos[j].stage[1] = MIN (feature_infos[j].stage[1], feature_infos[i].stage[1]);
 179       }
 180     feature_infos.shrink (j + 1);
 181   }
 182
 183
 184   /* Allocate bits now */
 185   unsigned int next_bit = 1;
 186   for (unsigned int i = 0; i < feature_infos.len; i++)
 187   {
 188     const feature_info_t *info = &feature_infos[i];
 189
 190     unsigned int bits_needed;
 191
 192     if ((info->flags & F_GLOBAL) && info->max_value == 1)
 193       /* Uses the global bit */
 194       bits_needed = 0;
 195     else
 196       bits_needed = _hb_bit_storage (info->max_value);
 197
 198     if (!info->max_value || next_bit + bits_needed > 8 * sizeof (hb_mask_t))
 199       continue; /* Feature disabled, or not enough bits. */
 200
 201
 202     hb_bool_t found = false;
 203     unsigned int feature_index[2];
 204     for (unsigned int table_index = 0; table_index < 2; table_index++)
 205     {
 206       if (required_feature_tag[table_index] == info->tag)
 207       {
 208         required_feature_stage[table_index] = info->stage[table_index];
 209         found = true;
 210         continue;
 211       }
 212       found |= hb_ot_layout_language_find_feature (face,
 213                                                    table_tags[table_index],
 214                                                    script_index[table_index],
 215                                                    language_index[table_index],
 216                                                    info->tag,
 217                                                    &feature_index[table_index]);
 218     }
 219     if (!found && !(info->flags & F_HAS_FALLBACK))
 220       continue;
 221
 222
 223     hb_ot_map_t::feature_map_t *map = m.features.push ();
 224     if (unlikely (!map))
 225       break;
 226
 227     map->tag = info->tag;
 228     map->index[0] = feature_index[0];
 229     map->index[1] = feature_index[1];
 230     map->stage[0] = info->stage[0];
 231     map->stage[1] = info->stage[1];
 232     map->auto_zwj = !(info->flags & F_MANUAL_ZWJ);
 233     if ((info->flags & F_GLOBAL) && info->max_value == 1) {
 234       /* Uses the global bit */
 235       map->shift = 0;
 236       map->mask = 1;
 237     } else {
 238       map->shift = next_bit;
 239       map->mask = (1 << (next_bit + bits_needed)) - (1 << next_bit);
 240       next_bit += bits_needed;
 241       m.global_mask |= (info->default_value << map->shift) & map->mask;
 242     }
 243     map->_1_mask = (1 << map->shift) & map->mask;
 244     map->needs_fallback = !found;
 245
 246   }
 247   feature_infos.shrink (0); /* Done with these */
 248
 249
 250   add_gsub_pause (NULL);
 251   add_gpos_pause (NULL);
 252
 253   for (unsigned int table_index = 0; table_index < 2; table_index++)
 254   {
 255     /* Collect lookup indices for features */
 256
 257     unsigned int stage_index = 0;
 258     unsigned int last_num_lookups = 0;
 259     for (unsigned stage = 0; stage < current_stage[table_index]; stage++)
 260     {
 261       if (required_feature_index[table_index] != HB_OT_LAYOUT_NO_FEATURE_INDEX &&
 262           required_feature_stage[table_index] == stage)
 263         m.add_lookups (face, table_index,
 264                        required_feature_index[table_index],
 265                        1 /* mask */,
 266                        true /* auto_zwj */);
 267
 268       for (unsigned i = 0; i < m.features.len; i++)
 269         if (m.features[i].stage[table_index] == stage)
 270           m.add_lookups (face, table_index,
 271                          m.features[i].index[table_index],
 272                          m.features[i].mask,
 273                          m.features[i].auto_zwj);
 274
 275       /* Sort lookups and merge duplicates */
 276       if (last_num_lookups < m.lookups[table_index].len)
 277       {
 278         m.lookups[table_index].qsort (last_num_lookups, m.lookups[table_index].len);
 279
 280         unsigned int j = last_num_lookups;
 281         for (unsigned int i = j + 1; i < m.lookups[table_index].len; i++)
 282           if (m.lookups[table_index][i].index != m.lookups[table_index][j].index)
 283             m.lookups[table_index][++j] = m.lookups[table_index][i];
 284           else
 285           {
 286             m.lookups[table_index][j].mask |= m.lookups[table_index][i].mask;
 287             m.lookups[table_index][j].auto_zwj &= m.lookups[table_index][i].auto_zwj;
 288           }
 289         m.lookups[table_index].shrink (j + 1);
 290       }
 291
 292       last_num_lookups = m.lookups[table_index].len;
 293
 294       if (stage_index < stages[table_index].len && stages[table_index][stage_index].index == stage) {
 295         hb_ot_map_t::stage_map_t *stage_map = m.stages[table_index].push ();
 296         if (likely (stage_map)) {
 297           stage_map->last_lookup = last_num_lookups;
 298           stage_map->pause_func = stages[table_index][stage_index].pause_func;
 299         }
 300
 301         stage_index++;
 302       }
 303     }
 304   }
 305 }