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                                   hb_face_t    *face,
  84                                   unsigned int  table_index,
  85                                   unsigned int  feature_index,
  86                                   unsigned int  variations_index,
  87                                   hb_mask_t     mask,
  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_zwj = auto_zwj;
 116     }
 117
 118     offset += len;
 119   } while (len == ARRAY_LENGTH (lookup_indices));
 120 }
 121
 122
 123 void hb_ot_map_builder_t::add_pause (unsigned int table_index, hb_ot_map_t::pause_func_t pause_func)
 124 {
 125   stage_info_t *s = stages[table_index].push ();
 126   if (likely (s)) {
 127     s->index = current_stage[table_index];
 128     s->pause_func = pause_func;
 129   }
 130
 131   current_stage[table_index]++;
 132 }
 133
 134 void
 135 hb_ot_map_builder_t::compile (hb_ot_map_t  &m,
 136                               const int    *coords,
 137                               unsigned int  num_coords)
 138 {
 139   m.global_mask = 1;
 140
 141   unsigned int required_feature_index[2];
 142   hb_tag_t required_feature_tag[2];
 143   /* We default to applying required feature in stage 0.  If the required
 144    * feature has a tag that is known to the shaper, we apply required feature
 145    * in the stage for that tag.
 146    */
 147   unsigned int required_feature_stage[2] = {0, 0};
 148
 149   for (unsigned int table_index = 0; table_index < 2; table_index++)
 150   {
 151     m.chosen_script[table_index] = chosen_script[table_index];
 152     m.found_script[table_index] = found_script[table_index];
 153
 154     hb_ot_layout_language_get_required_feature (face,
 155                                                 table_tags[table_index],
 156                                                 script_index[table_index],
 157                                                 language_index[table_index],
 158                                                 &required_feature_index[table_index],
 159                                                 &required_feature_tag[table_index]);
 160   }
 161
 162   if (!feature_infos.len)
 163     return;
 164
 165   /* Sort features and merge duplicates */
 166   {
 167     feature_infos.qsort ();
 168     unsigned int j = 0;
 169     for (unsigned int i = 1; i < feature_infos.len; i++)
 170       if (feature_infos[i].tag != feature_infos[j].tag)
 171         feature_infos[++j] = feature_infos[i];
 172       else {
 173         if (feature_infos[i].flags & F_GLOBAL) {
 174           feature_infos[j].flags |= F_GLOBAL;
 175           feature_infos[j].max_value = feature_infos[i].max_value;
 176           feature_infos[j].default_value = feature_infos[i].default_value;
 177         } else {
 178           feature_infos[j].flags &= ~F_GLOBAL;
 179           feature_infos[j].max_value = MAX (feature_infos[j].max_value, feature_infos[i].max_value);
 180           /* Inherit default_value from j */
 181         }
 182         feature_infos[j].flags |= (feature_infos[i].flags & F_HAS_FALLBACK);
 183         feature_infos[j].stage[0] = MIN (feature_infos[j].stage[0], feature_infos[i].stage[0]);
 184         feature_infos[j].stage[1] = MIN (feature_infos[j].stage[1], feature_infos[i].stage[1]);
 185       }
 186     feature_infos.shrink (j + 1);
 187   }
 188
 189
 190   /* Allocate bits now */
 191   unsigned int next_bit = 1;
 192   for (unsigned int i = 0; i < feature_infos.len; i++)
 193   {
 194     const feature_info_t *info = &feature_infos[i];
 195
 196     unsigned int bits_needed;
 197
 198     if ((info->flags & F_GLOBAL) && info->max_value == 1)
 199       /* Uses the global bit */
 200       bits_needed = 0;
 201     else
 202       /* Limit to 8 bits per feature. */
 203       bits_needed = MIN(8u, _hb_bit_storage (info->max_value));
 204
 205     if (!info->max_value || next_bit + bits_needed > 8 * sizeof (hb_mask_t))
 206       continue; /* Feature disabled, or not enough bits. */
 207
 208
 209     hb_bool_t found = false;
 210     unsigned int feature_index[2];
 211     for (unsigned int table_index = 0; table_index < 2; table_index++)
 212     {
 213       if (required_feature_tag[table_index] == info->tag)
 214         required_feature_stage[table_index] = info->stage[table_index];
 215
 216       found |= hb_ot_layout_language_find_feature (face,
 217                                                    table_tags[table_index],
 218                                                    script_index[table_index],
 219                                                    language_index[table_index],
 220                                                    info->tag,
 221                                                    &feature_index[table_index]);
 222     }
 223     if (!found && (info->flags & F_GLOBAL_SEARCH))
 224     {
 225       for (unsigned int table_index = 0; table_index < 2; table_index++)
 226       {
 227         found |= hb_ot_layout_table_find_feature (face,
 228                                                   table_tags[table_index],
 229                                                   info->tag,
 230                                                   &feature_index[table_index]);
 231       }
 232     }
 233     if (!found && !(info->flags & F_HAS_FALLBACK))
 234       continue;
 235
 236
 237     hb_ot_map_t::feature_map_t *map = m.features.push ();
 238     if (unlikely (!map))
 239       break;
 240
 241     map->tag = info->tag;
 242     map->index[0] = feature_index[0];
 243     map->index[1] = feature_index[1];
 244     map->stage[0] = info->stage[0];
 245     map->stage[1] = info->stage[1];
 246     map->auto_zwj = !(info->flags & F_MANUAL_ZWJ);
 247     if ((info->flags & F_GLOBAL) && info->max_value == 1) {
 248       /* Uses the global bit */
 249       map->shift = 0;
 250       map->mask = 1;
 251     } else {
 252       map->shift = next_bit;
 253       map->mask = (1u << (next_bit + bits_needed)) - (1u << next_bit);
 254       next_bit += bits_needed;
 255       m.global_mask |= (info->default_value << map->shift) & map->mask;
 256     }
 257     map->_1_mask = (1u << map->shift) & map->mask;
 258     map->needs_fallback = !found;
 259
 260   }
 261   feature_infos.shrink (0); /* Done with these */
 262
 263
 264   add_gsub_pause (NULL);
 265   add_gpos_pause (NULL);
 266
 267   for (unsigned int table_index = 0; table_index < 2; table_index++)
 268   {
 269     /* Collect lookup indices for features */
 270
 271     unsigned int variations_index;
 272     hb_ot_layout_table_find_feature_variations (face,
 273                                                 table_tags[table_index],
 274                                                 coords,
 275                                                 num_coords,
 276                                                 &variations_index);
 277
 278     unsigned int stage_index = 0;
 279     unsigned int last_num_lookups = 0;
 280     for (unsigned stage = 0; stage < current_stage[table_index]; stage++)
 281     {
 282       if (required_feature_index[table_index] != HB_OT_LAYOUT_NO_FEATURE_INDEX &&
 283           required_feature_stage[table_index] == stage)
 284         add_lookups (m, face, table_index,
 285                      required_feature_index[table_index],
 286                      variations_index,
 287                      1 /* mask */,
 288                      true /* auto_zwj */);
 289
 290       for (unsigned i = 0; i < m.features.len; i++)
 291         if (m.features[i].stage[table_index] == stage)
 292           add_lookups (m, face, table_index,
 293                        m.features[i].index[table_index],
 294                        variations_index,
 295                        m.features[i].mask,
 296                        m.features[i].auto_zwj);
 297
 298       /* Sort lookups and merge duplicates */
 299       if (last_num_lookups < m.lookups[table_index].len)
 300       {
 301         m.lookups[table_index].qsort (last_num_lookups, m.lookups[table_index].len);
 302
 303         unsigned int j = last_num_lookups;
 304         for (unsigned int i = j + 1; i < m.lookups[table_index].len; i++)
 305           if (m.lookups[table_index][i].index != m.lookups[table_index][j].index)
 306             m.lookups[table_index][++j] = m.lookups[table_index][i];
 307           else
 308           {
 309             m.lookups[table_index][j].mask |= m.lookups[table_index][i].mask;
 310             m.lookups[table_index][j].auto_zwj &= m.lookups[table_index][i].auto_zwj;
 311           }
 312         m.lookups[table_index].shrink (j + 1);
 313       }
 314
 315       last_num_lookups = m.lookups[table_index].len;
 316
 317       if (stage_index < stages[table_index].len && stages[table_index][stage_index].index == stage) {
 318         hb_ot_map_t::stage_map_t *stage_map = m.stages[table_index].push ();
 319         if (likely (stage_map)) {
 320           stage_map->last_lookup = last_num_lookups;
 321           stage_map->pause_func = stages[table_index][stage_index].pause_func;
 322         }
 323
 324         stage_index++;
 325       }
 326     }
 327   }
 328 }