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   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   hb_tag_t script_tags[3] = {HB_TAG_NONE, HB_TAG_NONE, HB_TAG_NONE};
  58   hb_tag_t language_tag;
  59
  60   hb_ot_tags_from_script (props.script, &script_tags[0], &script_tags[1]);
  61   language_tag = hb_ot_tag_from_language (props.language);
  62
  63   for (unsigned int table_index = 0; table_index < 2; table_index++) {
  64     hb_tag_t table_tag = table_tags[table_index];
  65     found_script[table_index] = (bool) hb_ot_layout_table_choose_script (face, table_tag, script_tags, &script_index[table_index], &chosen_script[table_index]);
  66     hb_ot_layout_script_find_language (face, table_tag, script_index[table_index], language_tag, &language_index[table_index]);
  67   }
  68 }
  69
  70 hb_ot_map_builder_t::~hb_ot_map_builder_t (void)
  71 {
  72   feature_infos.fini ();
  73   for (unsigned int table_index = 0; table_index < 2; table_index++)
  74     stages[table_index].fini ();
  75 }
  76
  77 void hb_ot_map_builder_t::add_feature (hb_tag_t tag, unsigned int value,
  78                                        hb_ot_map_feature_flags_t flags)
  79 {
  80   feature_info_t *info = feature_infos.push();
  81   if (unlikely (!tag)) return;
  82   info->tag = tag;
  83   info->seq = feature_infos.len;
  84   info->max_value = value;
  85   info->flags = flags;
  86   info->default_value = (flags & F_GLOBAL) ? value : 0;
  87   info->stage[0] = current_stage[0];
  88   info->stage[1] = current_stage[1];
  89 }
  90
  91 void
  92 hb_ot_map_builder_t::add_lookups (hb_ot_map_t  &m,
  93                                   unsigned int  table_index,
  94                                   unsigned int  feature_index,
  95                                   unsigned int  variations_index,
  96                                   hb_mask_t     mask,
  97                                   bool          auto_zwnj,
  98                                   bool          auto_zwj)
  99 {
 100   unsigned int lookup_indices[32];
 101   unsigned int offset, len;
 102   unsigned int table_lookup_count;
 103
 104   table_lookup_count = hb_ot_layout_table_get_lookup_count (face, table_tags[table_index]);
 105
 106   offset = 0;
 107   do {
 108     len = ARRAY_LENGTH (lookup_indices);
 109     hb_ot_layout_feature_with_variations_get_lookups (face,
 110                                                       table_tags[table_index],
 111                                                       feature_index,
 112                                                       variations_index,
 113                                                       offset, &len,
 114                                                       lookup_indices);
 115
 116     for (unsigned int i = 0; i < len; i++)
 117     {
 118       if (lookup_indices[i] >= table_lookup_count)
 119         continue;
 120       hb_ot_map_t::lookup_map_t *lookup = m.lookups[table_index].push ();
 121       lookup->mask = mask;
 122       lookup->index = lookup_indices[i];
 123       lookup->auto_zwnj = auto_zwnj;
 124       lookup->auto_zwj = auto_zwj;
 125     }
 126
 127     offset += len;
 128   } while (len == ARRAY_LENGTH (lookup_indices));
 129 }
 130
 131
 132 void hb_ot_map_builder_t::add_pause (unsigned int table_index, hb_ot_map_t::pause_func_t pause_func)
 133 {
 134   stage_info_t *s = stages[table_index].push ();
 135   s->index = current_stage[table_index];
 136   s->pause_func = pause_func;
 137
 138   current_stage[table_index]++;
 139 }
 140
 141 void
 142 hb_ot_map_builder_t::compile (hb_ot_map_t  &m,
 143                               const int    *coords,
 144                               unsigned int  num_coords)
 145 {
 146   static_assert ((!(HB_GLYPH_FLAG_DEFINED & (HB_GLYPH_FLAG_DEFINED + 1))), "");
 147   unsigned int global_bit_mask = HB_GLYPH_FLAG_DEFINED + 1;
 148   unsigned int global_bit_shift = _hb_popcount (HB_GLYPH_FLAG_DEFINED);
 149
 150   m.global_mask = global_bit_mask;
 151
 152   unsigned int required_feature_index[2];
 153   hb_tag_t required_feature_tag[2];
 154   /* We default to applying required feature in stage 0.  If the required
 155    * feature has a tag that is known to the shaper, we apply required feature
 156    * in the stage for that tag.
 157    */
 158   unsigned int required_feature_stage[2] = {0, 0};
 159
 160   for (unsigned int table_index = 0; table_index < 2; table_index++)
 161   {
 162     m.chosen_script[table_index] = chosen_script[table_index];
 163     m.found_script[table_index] = found_script[table_index];
 164
 165     hb_ot_layout_language_get_required_feature (face,
 166                                                 table_tags[table_index],
 167                                                 script_index[table_index],
 168                                                 language_index[table_index],
 169                                                 &required_feature_index[table_index],
 170                                                 &required_feature_tag[table_index]);
 171   }
 172
 173   /* Sort features and merge duplicates */
 174   {
 175     feature_infos.qsort ();
 176     unsigned int j = 0;
 177     for (unsigned int i = 1; i < feature_infos.len; i++)
 178       if (feature_infos[i].tag != feature_infos[j].tag)
 179         feature_infos[++j] = feature_infos[i];
 180       else {
 181         if (feature_infos[i].flags & F_GLOBAL) {
 182           feature_infos[j].flags |= F_GLOBAL;
 183           feature_infos[j].max_value = feature_infos[i].max_value;
 184           feature_infos[j].default_value = feature_infos[i].default_value;
 185         } else {
 186           feature_infos[j].flags &= ~F_GLOBAL;
 187           feature_infos[j].max_value = MAX (feature_infos[j].max_value, feature_infos[i].max_value);
 188           /* Inherit default_value from j */
 189         }
 190         feature_infos[j].flags |= (feature_infos[i].flags & F_HAS_FALLBACK);
 191         feature_infos[j].stage[0] = MIN (feature_infos[j].stage[0], feature_infos[i].stage[0]);
 192         feature_infos[j].stage[1] = MIN (feature_infos[j].stage[1], feature_infos[i].stage[1]);
 193       }
 194     feature_infos.shrink (j + 1);
 195   }
 196
 197
 198   /* Allocate bits now */
 199   unsigned int next_bit = global_bit_shift + 1;
 200
 201   for (unsigned int i = 0; i < feature_infos.len; i++)
 202   {
 203     const feature_info_t *info = &feature_infos[i];
 204
 205     unsigned int bits_needed;
 206
 207     if ((info->flags & F_GLOBAL) && info->max_value == 1)
 208       /* Uses the global bit */
 209       bits_needed = 0;
 210     else
 211       /* Limit to 8 bits per feature. */
 212       bits_needed = MIN(8u, _hb_bit_storage (info->max_value));
 213
 214     if (!info->max_value || next_bit + bits_needed > 8 * sizeof (hb_mask_t))
 215       continue; /* Feature disabled, or not enough bits. */
 216
 217
 218     hb_bool_t found = false;
 219     unsigned int feature_index[2];
 220     for (unsigned int table_index = 0; table_index < 2; table_index++)
 221     {
 222       if (required_feature_tag[table_index] == info->tag)
 223         required_feature_stage[table_index] = info->stage[table_index];
 224
 225       found |= hb_ot_layout_language_find_feature (face,
 226                                                    table_tags[table_index],
 227                                                    script_index[table_index],
 228                                                    language_index[table_index],
 229                                                    info->tag,
 230                                                    &feature_index[table_index]);
 231     }
 232     if (!found && (info->flags & F_GLOBAL_SEARCH))
 233     {
 234       for (unsigned int table_index = 0; table_index < 2; table_index++)
 235       {
 236         found |= hb_ot_layout_table_find_feature (face,
 237                                                   table_tags[table_index],
 238                                                   info->tag,
 239                                                   &feature_index[table_index]);
 240       }
 241     }
 242     if (!found && !(info->flags & F_HAS_FALLBACK))
 243       continue;
 244
 245
 246     hb_ot_map_t::feature_map_t *map = m.features.push ();
 247
 248     map->tag = info->tag;
 249     map->index[0] = feature_index[0];
 250     map->index[1] = feature_index[1];
 251     map->stage[0] = info->stage[0];
 252     map->stage[1] = info->stage[1];
 253     map->auto_zwnj = !(info->flags & F_MANUAL_ZWNJ);
 254     map->auto_zwj = !(info->flags & F_MANUAL_ZWJ);
 255     if ((info->flags & F_GLOBAL) && info->max_value == 1) {
 256       /* Uses the global bit */
 257       map->shift = global_bit_shift;
 258       map->mask = global_bit_mask;
 259     } else {
 260       map->shift = next_bit;
 261       map->mask = (1u << (next_bit + bits_needed)) - (1u << next_bit);
 262       next_bit += bits_needed;
 263       m.global_mask |= (info->default_value << map->shift) & map->mask;
 264     }
 265     map->_1_mask = (1u << map->shift) & map->mask;
 266     map->needs_fallback = !found;
 267
 268   }
 269   feature_infos.shrink (0); /* Done with these */
 270
 271
 272   add_gsub_pause (nullptr);
 273   add_gpos_pause (nullptr);
 274
 275   for (unsigned int table_index = 0; table_index < 2; table_index++)
 276   {
 277     /* Collect lookup indices for features */
 278
 279     unsigned int variations_index;
 280     hb_ot_layout_table_find_feature_variations (face,
 281                                                 table_tags[table_index],
 282                                                 coords,
 283                                                 num_coords,
 284                                                 &variations_index);
 285
 286     unsigned int stage_index = 0;
 287     unsigned int last_num_lookups = 0;
 288     for (unsigned stage = 0; stage < current_stage[table_index]; stage++)
 289     {
 290       if (required_feature_index[table_index] != HB_OT_LAYOUT_NO_FEATURE_INDEX &&
 291           required_feature_stage[table_index] == stage)
 292         add_lookups (m, table_index,
 293                      required_feature_index[table_index],
 294                      variations_index,
 295                      global_bit_mask);
 296
 297       for (unsigned i = 0; i < m.features.len; i++)
 298         if (m.features[i].stage[table_index] == stage)
 299           add_lookups (m, table_index,
 300                        m.features[i].index[table_index],
 301                        variations_index,
 302                        m.features[i].mask,
 303                        m.features[i].auto_zwnj,
 304                        m.features[i].auto_zwj);
 305
 306       /* Sort lookups and merge duplicates */
 307       if (last_num_lookups < m.lookups[table_index].len)
 308       {
 309         m.lookups[table_index].qsort (last_num_lookups, m.lookups[table_index].len);
 310
 311         unsigned int j = last_num_lookups;
 312         for (unsigned int i = j + 1; i < m.lookups[table_index].len; i++)
 313           if (m.lookups[table_index][i].index != m.lookups[table_index][j].index)
 314             m.lookups[table_index][++j] = m.lookups[table_index][i];
 315           else
 316           {
 317             m.lookups[table_index][j].mask |= m.lookups[table_index][i].mask;
 318             m.lookups[table_index][j].auto_zwnj &= m.lookups[table_index][i].auto_zwnj;
 319             m.lookups[table_index][j].auto_zwj &= m.lookups[table_index][i].auto_zwj;
 320           }
 321         m.lookups[table_index].shrink (j + 1);
 322       }
 323
 324       last_num_lookups = m.lookups[table_index].len;
 325
 326       if (stage_index < stages[table_index].len && stages[table_index][stage_index].index == stage) {
 327         hb_ot_map_t::stage_map_t *stage_map = m.stages[table_index].push ();
 328         stage_map->last_lookup = last_num_lookups;
 329         stage_map->pause_func = stages[table_index][stage_index].pause_func;
 330
 331         stage_index++;
 332       }
 333     }
 334   }
 335 }