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
  44   offset = 0;
  45   do {
  46     len = ARRAY_LENGTH (lookup_indices);
  47     hb_ot_layout_feature_get_lookups (face,
  48                                       table_tags[table_index],
  49                                       feature_index,
  50                                       offset, &len,
  51                                       lookup_indices);
  52
  53     for (unsigned int i = 0; i < len; i++) {
  54       hb_ot_map_t::lookup_map_t *lookup = lookups[table_index].push ();
  55       if (unlikely (!lookup))
  56         return;
  57       lookup->mask = mask;
  58       lookup->index = lookup_indices[i];
  59       lookup->auto_zwj = auto_zwj;
  60     }
  61
  62     offset += len;
  63   } while (len == ARRAY_LENGTH (lookup_indices));
  64 }
  65
  66 hb_ot_map_builder_t::hb_ot_map_builder_t (hb_face_t *face_,
  67                                           const hb_segment_properties_t *props_)
  68 {
  69   memset (this, 0, sizeof (*this));
  70
  71   face = face_;
  72   props = *props_;
  73
  74
  75   /* Fetch script/language indices for GSUB/GPOS.  We need these later to skip
  76    * features not available in either table and not waste precious bits for them. */
  77
  78   hb_tag_t script_tags[3] = {HB_TAG_NONE, HB_TAG_NONE, HB_TAG_NONE};
  79   hb_tag_t language_tag;
  80
  81   hb_ot_tags_from_script (props.script, &script_tags[0], &script_tags[1]);
  82   language_tag = hb_ot_tag_from_language (props.language);
  83
  84   for (unsigned int table_index = 0; table_index < 2; table_index++) {
  85     hb_tag_t table_tag = table_tags[table_index];
  86     found_script[table_index] = hb_ot_layout_table_choose_script (face, table_tag, script_tags, &script_index[table_index], &chosen_script[table_index]);
  87     hb_ot_layout_script_find_language (face, table_tag, script_index[table_index], language_tag, &language_index[table_index]);
  88   }
  89 }
  90
  91 void hb_ot_map_builder_t::add_feature (hb_tag_t tag, unsigned int value,
  92                                        hb_ot_map_feature_flags_t flags)
  93 {
  94   feature_info_t *info = feature_infos.push();
  95   if (unlikely (!info)) return;
  96   info->tag = tag;
  97   info->seq = feature_infos.len;
  98   info->max_value = value;
  99   info->flags = flags;
 100   info->default_value = (flags & F_GLOBAL) ? value : 0;
 101   info->stage[0] = current_stage[0];
 102   info->stage[1] = current_stage[1];
 103 }
 104
 105 inline void hb_ot_map_t::apply (unsigned int table_index,
 106                                 const hb_ot_shape_plan_t *plan,
 107                                 hb_font_t *font,
 108                                 hb_buffer_t *buffer) const
 109 {
 110   unsigned int i = 0;
 111
 112   for (unsigned int stage_index = 0; stage_index < stages[table_index].len; stage_index++) {
 113     const stage_map_t *stage = &stages[table_index][stage_index];
 114     for (; i < stage->last_lookup; i++)
 115       switch (table_index)
 116       {
 117         case 0:
 118           hb_ot_layout_substitute_lookup (font, buffer, lookups[table_index][i].index,
 119                                           lookups[table_index][i].mask,
 120                                           lookups[table_index][i].auto_zwj);
 121           break;
 122
 123         case 1:
 124           hb_ot_layout_position_lookup (font, buffer, lookups[table_index][i].index,
 125                                         lookups[table_index][i].mask,
 126                                         lookups[table_index][i].auto_zwj);
 127           break;
 128       }
 129
 130     if (stage->pause_func)
 131     {
 132       buffer->clear_output ();
 133       stage->pause_func (plan, font, buffer);
 134     }
 135   }
 136 }
 137
 138 void hb_ot_map_t::substitute (const hb_ot_shape_plan_t *plan, hb_font_t *font, hb_buffer_t *buffer) const
 139 {
 140   apply (0, plan, font, buffer);
 141 }
 142
 143 void hb_ot_map_t::position (const hb_ot_shape_plan_t *plan, hb_font_t *font, hb_buffer_t *buffer) const
 144 {
 145   apply (1, plan, font, buffer);
 146 }
 147
 148
 149 void hb_ot_map_t::collect_lookups (unsigned int table_index, hb_set_t *lookups_out) const
 150 {
 151   for (unsigned int i = 0; i < lookups[table_index].len; i++)
 152     hb_set_add (lookups_out, lookups[table_index][i].index);
 153 }
 154
 155 void hb_ot_map_builder_t::add_pause (unsigned int table_index, hb_ot_map_t::pause_func_t pause_func)
 156 {
 157   stage_info_t *s = stages[table_index].push ();
 158   if (likely (s)) {
 159     s->index = current_stage[table_index];
 160     s->pause_func = pause_func;
 161   }
 162
 163   current_stage[table_index]++;
 164 }
 165
 166 void
 167 hb_ot_map_builder_t::compile (hb_ot_map_t &m)
 168 {
 169   m.global_mask = 1;
 170
 171   for (unsigned int table_index = 0; table_index < 2; table_index++) {
 172     m.chosen_script[table_index] = chosen_script[table_index];
 173     m.found_script[table_index] = found_script[table_index];
 174   }
 175
 176   if (!feature_infos.len)
 177     return;
 178
 179   /* Sort features and merge duplicates */
 180   {
 181     feature_infos.sort ();
 182     unsigned int j = 0;
 183     for (unsigned int i = 1; i < feature_infos.len; i++)
 184       if (feature_infos[i].tag != feature_infos[j].tag)
 185         feature_infos[++j] = feature_infos[i];
 186       else {
 187         if (feature_infos[i].flags & F_GLOBAL) {
 188           feature_infos[j].flags |= F_GLOBAL;
 189           feature_infos[j].max_value = feature_infos[i].max_value;
 190           feature_infos[j].default_value = feature_infos[i].default_value;
 191         } else {
 192           feature_infos[j].flags &= ~F_GLOBAL;
 193           feature_infos[j].max_value = MAX (feature_infos[j].max_value, feature_infos[i].max_value);
 194           /* Inherit default_value from j */
 195         }
 196         feature_infos[j].flags |= (feature_infos[i].flags & F_HAS_FALLBACK);
 197         feature_infos[j].stage[0] = MIN (feature_infos[j].stage[0], feature_infos[i].stage[0]);
 198         feature_infos[j].stage[1] = MIN (feature_infos[j].stage[1], feature_infos[i].stage[1]);
 199       }
 200     feature_infos.shrink (j + 1);
 201   }
 202
 203
 204   /* Allocate bits now */
 205   unsigned int next_bit = 1;
 206   for (unsigned int i = 0; i < feature_infos.len; i++) {
 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       bits_needed = _hb_bit_storage (info->max_value);
 216
 217     if (!info->max_value || next_bit + bits_needed > 8 * sizeof (hb_mask_t))
 218       continue; /* Feature disabled, or not enough bits. */
 219
 220
 221     bool found = false;
 222     unsigned int feature_index[2];
 223     for (unsigned int table_index = 0; table_index < 2; table_index++)
 224       found |= hb_ot_layout_language_find_feature (face,
 225                                                    table_tags[table_index],
 226                                                    script_index[table_index],
 227                                                    language_index[table_index],
 228                                                    info->tag,
 229                                                    &feature_index[table_index]);
 230     if (!found && !(info->flags & F_HAS_FALLBACK))
 231       continue;
 232
 233
 234     hb_ot_map_t::feature_map_t *map = m.features.push ();
 235     if (unlikely (!map))
 236       break;
 237
 238     map->tag = info->tag;
 239     map->index[0] = feature_index[0];
 240     map->index[1] = feature_index[1];
 241     map->stage[0] = info->stage[0];
 242     map->stage[1] = info->stage[1];
 243     map->auto_zwj = !(info->flags & F_MANUAL_ZWJ);
 244     if ((info->flags & F_GLOBAL) && info->max_value == 1) {
 245       /* Uses the global bit */
 246       map->shift = 0;
 247       map->mask = 1;
 248     } else {
 249       map->shift = next_bit;
 250       map->mask = (1 << (next_bit + bits_needed)) - (1 << next_bit);
 251       next_bit += bits_needed;
 252       m.global_mask |= (info->default_value << map->shift) & map->mask;
 253     }
 254     map->_1_mask = (1 << map->shift) & map->mask;
 255     map->needs_fallback = !found;
 256
 257   }
 258   feature_infos.shrink (0); /* Done with these */
 259
 260
 261   add_gsub_pause (NULL);
 262   add_gpos_pause (NULL);
 263
 264   for (unsigned int table_index = 0; table_index < 2; table_index++) {
 265     hb_tag_t table_tag = table_tags[table_index];
 266
 267     /* Collect lookup indices for features */
 268
 269     unsigned int required_feature_index;
 270     if (hb_ot_layout_language_get_required_feature_index (face,
 271                                                           table_tag,
 272                                                           script_index[table_index],
 273                                                           language_index[table_index],
 274                                                           &required_feature_index))
 275       m.add_lookups (face, table_index, required_feature_index, 1, true);
 276
 277     unsigned int stage_index = 0;
 278     unsigned int last_num_lookups = 0;
 279     for (unsigned stage = 0; stage < current_stage[table_index]; stage++)
 280     {
 281       for (unsigned i = 0; i < m.features.len; i++)
 282         if (m.features[i].stage[table_index] == stage)
 283           m.add_lookups (face, table_index,
 284                          m.features[i].index[table_index],
 285                          m.features[i].mask,
 286                          m.features[i].auto_zwj);
 287
 288       /* Sort lookups and merge duplicates */
 289       if (last_num_lookups < m.lookups[table_index].len)
 290       {
 291         m.lookups[table_index].sort (last_num_lookups, m.lookups[table_index].len);
 292
 293         unsigned int j = last_num_lookups;
 294         for (unsigned int i = j + 1; i < m.lookups[table_index].len; i++)
 295           if (m.lookups[table_index][i].index != m.lookups[table_index][j].index)
 296             m.lookups[table_index][++j] = m.lookups[table_index][i];
 297           else
 298           {
 299             m.lookups[table_index][j].mask |= m.lookups[table_index][i].mask;
 300             m.lookups[table_index][j].auto_zwj &= m.lookups[table_index][i].auto_zwj;
 301           }
 302         m.lookups[table_index].shrink (j + 1);
 303       }
 304
 305       last_num_lookups = m.lookups[table_index].len;
 306
 307       if (stage_index < stages[table_index].len && stages[table_index][stage_index].index == stage) {
 308         hb_ot_map_t::stage_map_t *stage_map = m.stages[table_index].push ();
 309         if (likely (stage_map)) {
 310           stage_map->last_lookup = last_num_lookups;
 311           stage_map->pause_func = stages[table_index][stage_index].pause_func;
 312         }
 313
 314         stage_index++;
 315       }
 316     }
 317   }
 318 }