third_party/harfbuzz-ng/src/hb-ot-layout-private.hh

   1 /*
   2  * Copyright © 2007,2008,2009  Red Hat, Inc.
   3  * Copyright © 2012,2013  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 #ifndef HB_OT_LAYOUT_PRIVATE_HH
  30 #define HB_OT_LAYOUT_PRIVATE_HH
  31
  32 #include "hb-private.hh"
  33
  34 #include "hb-ot-layout.h"
  35
  36 #include "hb-font-private.hh"
  37 #include "hb-buffer-private.hh"
  38 #include "hb-set-private.hh"
  39
  40
  41 /*
  42  * GDEF
  43  */
  44
  45 typedef enum
  46 {
  47   /* The following three match LookupFlags::Ignore* numbers. */
  48   HB_OT_LAYOUT_GLYPH_PROPS_BASE_GLYPH   = 0x02u,
  49   HB_OT_LAYOUT_GLYPH_PROPS_LIGATURE     = 0x04u,
  50   HB_OT_LAYOUT_GLYPH_PROPS_MARK         = 0x08u,
  51
  52   /* The following are used internally; not derived from GDEF. */
  53   HB_OT_LAYOUT_GLYPH_PROPS_SUBSTITUTED  = 0x10u,
  54   HB_OT_LAYOUT_GLYPH_PROPS_LIGATED      = 0x20u,
  55
  56   HB_OT_LAYOUT_GLYPH_PROPS_PRESERVE     = HB_OT_LAYOUT_GLYPH_PROPS_SUBSTITUTED |
  57                                           HB_OT_LAYOUT_GLYPH_PROPS_LIGATED
  58 } hb_ot_layout_glyph_class_mask_t;
  59
  60
  61 /*
  62  * GSUB/GPOS
  63  */
  64
  65 HB_INTERNAL hb_bool_t
  66 hb_ot_layout_lookup_would_substitute_fast (hb_face_t            *face,
  67                                            unsigned int          lookup_index,
  68                                            const hb_codepoint_t *glyphs,
  69                                            unsigned int          glyphs_length,
  70                                            hb_bool_t             zero_context);
  71
  72
  73 /* Should be called before all the substitute_lookup's are done. */
  74 HB_INTERNAL void
  75 hb_ot_layout_substitute_start (hb_font_t    *font,
  76                                hb_buffer_t  *buffer);
  77
  78
  79 struct hb_ot_layout_lookup_accelerator_t;
  80
  81 namespace OT {
  82   struct hb_apply_context_t;
  83   struct SubstLookup;
  84 }
  85
  86 HB_INTERNAL void
  87 hb_ot_layout_substitute_lookup (OT::hb_apply_context_t *c,
  88                                 const OT::SubstLookup &lookup,
  89                                 const hb_ot_layout_lookup_accelerator_t &accel);
  90
  91
  92 /* Should be called after all the substitute_lookup's are done */
  93 HB_INTERNAL void
  94 hb_ot_layout_substitute_finish (hb_font_t    *font,
  95                                 hb_buffer_t  *buffer);
  96
  97
  98 /* Should be called before all the position_lookup's are done.  Resets positions to zero. */
  99 HB_INTERNAL void
 100 hb_ot_layout_position_start (hb_font_t    *font,
 101                              hb_buffer_t  *buffer);
 102
 103 /* Should be called after all the position_lookup's are done */
 104 HB_INTERNAL void
 105 hb_ot_layout_position_finish (hb_font_t    *font,
 106                               hb_buffer_t  *buffer);
 107
 108
 109
 110 /*
 111  * hb_ot_layout_t
 112  */
 113
 114 namespace OT {
 115   struct GDEF;
 116   struct GSUB;
 117   struct GPOS;
 118 }
 119
 120 struct hb_ot_layout_lookup_accelerator_t
 121 {
 122   template <typename TLookup>
 123   inline void init (const TLookup &lookup)
 124   {
 125     digest.init ();
 126     lookup.add_coverage (&digest);
 127   }
 128
 129   template <typename TLookup>
 130   inline void fini (const TLookup &lookup)
 131   {
 132   }
 133
 134   hb_set_digest_t digest;
 135 };
 136
 137 struct hb_ot_layout_t
 138 {
 139   hb_blob_t *gdef_blob;
 140   hb_blob_t *gsub_blob;
 141   hb_blob_t *gpos_blob;
 142
 143   const struct OT::GDEF *gdef;
 144   const struct OT::GSUB *gsub;
 145   const struct OT::GPOS *gpos;
 146
 147   unsigned int gsub_lookup_count;
 148   unsigned int gpos_lookup_count;
 149
 150   hb_ot_layout_lookup_accelerator_t *gsub_accels;
 151   hb_ot_layout_lookup_accelerator_t *gpos_accels;
 152 };
 153
 154
 155 HB_INTERNAL hb_ot_layout_t *
 156 _hb_ot_layout_create (hb_face_t *face);
 157
 158 HB_INTERNAL void
 159 _hb_ot_layout_destroy (hb_ot_layout_t *layout);
 160
 161
 162 #define hb_ot_layout_from_face(face) ((hb_ot_layout_t *) face->shaper_data.ot)
 163
 164
 165 /*
 166  * Buffer var routines.
 167  */
 168
 169 /* buffer var allocations, used during the entire shaping process */
 170 #define unicode_props0()        var2.u8[0]
 171 #define unicode_props1()        var2.u8[1]
 172
 173 /* buffer var allocations, used during the GSUB/GPOS processing */
 174 #define glyph_props()           var1.u16[0] /* GDEF glyph properties */
 175 #define lig_props()             var1.u8[2] /* GSUB/GPOS ligature tracking */
 176 #define syllable()              var1.u8[3] /* GSUB/GPOS shaping boundaries */
 177
 178 /* unicode_props */
 179
 180 enum {
 181   MASK0_ZWJ       = 0x20u,
 182   MASK0_ZWNJ      = 0x40u,
 183   MASK0_IGNORABLE = 0x80u,
 184   MASK0_GEN_CAT   = 0x1Fu
 185 };
 186
 187 inline void
 188 _hb_glyph_info_set_unicode_props (hb_glyph_info_t *info, hb_unicode_funcs_t *unicode)
 189 {
 190   /* XXX This shouldn't be inlined, or at least not while is_default_ignorable() is inline. */
 191   info->unicode_props0() = ((unsigned int) unicode->general_category (info->codepoint)) |
 192                            (unicode->is_default_ignorable (info->codepoint) ? MASK0_IGNORABLE : 0) |
 193                            (info->codepoint == 0x200C ? MASK0_ZWNJ : 0) |
 194                            (info->codepoint == 0x200D ? MASK0_ZWJ : 0);
 195   info->unicode_props1() = unicode->modified_combining_class (info->codepoint);
 196 }
 197
 198 inline void
 199 _hb_glyph_info_set_general_category (hb_glyph_info_t *info,
 200                                      hb_unicode_general_category_t gen_cat)
 201 {
 202   info->unicode_props0() = (unsigned int) gen_cat | ((info->unicode_props0()) & ~MASK0_GEN_CAT);
 203 }
 204
 205 inline hb_unicode_general_category_t
 206 _hb_glyph_info_get_general_category (const hb_glyph_info_t *info)
 207 {
 208   return (hb_unicode_general_category_t) (info->unicode_props0() & MASK0_GEN_CAT);
 209 }
 210
 211 inline void
 212 _hb_glyph_info_set_modified_combining_class (hb_glyph_info_t *info,
 213                                              unsigned int modified_class)
 214 {
 215   info->unicode_props1() = modified_class;
 216 }
 217
 218 inline unsigned int
 219 _hb_glyph_info_get_modified_combining_class (const hb_glyph_info_t *info)
 220 {
 221   return info->unicode_props1();
 222 }
 223
 224 inline hb_bool_t
 225 _hb_glyph_info_is_default_ignorable (const hb_glyph_info_t *info)
 226 {
 227   return !!(info->unicode_props0() & MASK0_IGNORABLE);
 228 }
 229
 230 inline hb_bool_t
 231 _hb_glyph_info_is_zwnj (const hb_glyph_info_t *info)
 232 {
 233   return !!(info->unicode_props0() & MASK0_ZWNJ);
 234 }
 235
 236 inline hb_bool_t
 237 _hb_glyph_info_is_zwj (const hb_glyph_info_t *info)
 238 {
 239   return !!(info->unicode_props0() & MASK0_ZWJ);
 240 }
 241
 242 inline void
 243 _hb_glyph_info_flip_joiners (hb_glyph_info_t *info)
 244 {
 245   info->unicode_props0() ^= MASK0_ZWNJ | MASK0_ZWJ;
 246 }
 247
 248 /* lig_props: aka lig_id / lig_comp
 249  *
 250  * When a ligature is formed:
 251  *
 252  *   - The ligature glyph and any marks in between all the same newly allocated
 253  *     lig_id,
 254  *   - The ligature glyph will get lig_num_comps set to the number of components
 255  *   - The marks get lig_comp > 0, reflecting which component of the ligature
 256  *     they were applied to.
 257  *   - This is used in GPOS to attach marks to the right component of a ligature
 258  *     in MarkLigPos,
 259  *   - Note that when marks are ligated together, much of the above is skipped
 260  *     and the current lig_id reused.
 261  *
 262  * When a multiple-substitution is done:
 263  *
 264  *   - All resulting glyphs will have lig_id = 0,
 265  *   - The resulting glyphs will have lig_comp = 0, 1, 2, ... respectively.
 266  *   - This is used in GPOS to attach marks to the first component of a
 267  *     multiple substitution in MarkBasePos.
 268  *
 269  * The numbers are also used in GPOS to do mark-to-mark positioning only
 270  * to marks that belong to the same component of the same ligature.
 271  */
 272
 273 static inline void
 274 _hb_glyph_info_clear_lig_props (hb_glyph_info_t *info)
 275 {
 276   info->lig_props() = 0;
 277 }
 278
 279 #define IS_LIG_BASE 0x10
 280
 281 static inline void
 282 _hb_glyph_info_set_lig_props_for_ligature (hb_glyph_info_t *info,
 283                                            unsigned int lig_id,
 284                                            unsigned int lig_num_comps)
 285 {
 286   info->lig_props() = (lig_id << 5) | IS_LIG_BASE | (lig_num_comps & 0x0F);
 287 }
 288
 289 static inline void
 290 _hb_glyph_info_set_lig_props_for_mark (hb_glyph_info_t *info,
 291                                        unsigned int lig_id,
 292                                        unsigned int lig_comp)
 293 {
 294   info->lig_props() = (lig_id << 5) | (lig_comp & 0x0F);
 295 }
 296
 297 static inline void
 298 _hb_glyph_info_set_lig_props_for_component (hb_glyph_info_t *info, unsigned int comp)
 299 {
 300   _hb_glyph_info_set_lig_props_for_mark (info, 0, comp);
 301 }
 302
 303 static inline unsigned int
 304 _hb_glyph_info_get_lig_id (const hb_glyph_info_t *info)
 305 {
 306   return info->lig_props() >> 5;
 307 }
 308
 309 static inline bool
 310 _hb_glyph_info_ligated_internal (const hb_glyph_info_t *info)
 311 {
 312   return !!(info->lig_props() & IS_LIG_BASE);
 313 }
 314
 315 static inline unsigned int
 316 _hb_glyph_info_get_lig_comp (const hb_glyph_info_t *info)
 317 {
 318   if (_hb_glyph_info_ligated_internal (info))
 319     return 0;
 320   else
 321     return info->lig_props() & 0x0F;
 322 }
 323
 324 static inline unsigned int
 325 _hb_glyph_info_get_lig_num_comps (const hb_glyph_info_t *info)
 326 {
 327   if ((info->glyph_props() & HB_OT_LAYOUT_GLYPH_PROPS_LIGATURE) &&
 328       _hb_glyph_info_ligated_internal (info))
 329     return info->lig_props() & 0x0F;
 330   else
 331     return 1;
 332 }
 333
 334 static inline uint8_t
 335 _hb_allocate_lig_id (hb_buffer_t *buffer) {
 336   uint8_t lig_id = buffer->next_serial () & 0x07;
 337   if (unlikely (!lig_id))
 338     lig_id = _hb_allocate_lig_id (buffer); /* in case of overflow */
 339   return lig_id;
 340 }
 341
 342 /* glyph_props: */
 343
 344 inline void
 345 _hb_glyph_info_set_glyph_props (hb_glyph_info_t *info, unsigned int props)
 346 {
 347   info->glyph_props() = props;
 348 }
 349
 350 inline unsigned int
 351 _hb_glyph_info_get_glyph_props (const hb_glyph_info_t *info)
 352 {
 353   return info->glyph_props();
 354 }
 355
 356 inline bool
 357 _hb_glyph_info_is_base_glyph (const hb_glyph_info_t *info)
 358 {
 359   return !!(info->glyph_props() & HB_OT_LAYOUT_GLYPH_PROPS_BASE_GLYPH);
 360 }
 361
 362 inline bool
 363 _hb_glyph_info_is_ligature (const hb_glyph_info_t *info)
 364 {
 365   return !!(info->glyph_props() & HB_OT_LAYOUT_GLYPH_PROPS_LIGATURE);
 366 }
 367
 368 inline bool
 369 _hb_glyph_info_is_mark (const hb_glyph_info_t *info)
 370 {
 371   return !!(info->glyph_props() & HB_OT_LAYOUT_GLYPH_PROPS_MARK);
 372 }
 373
 374 static inline bool
 375 _hb_glyph_info_substituted (const hb_glyph_info_t *info)
 376 {
 377   return !!(info->glyph_props() & HB_OT_LAYOUT_GLYPH_PROPS_SUBSTITUTED);
 378 }
 379
 380 static inline bool
 381 _hb_glyph_info_ligated (const hb_glyph_info_t *info)
 382 {
 383   return !!(info->glyph_props() & HB_OT_LAYOUT_GLYPH_PROPS_LIGATED);
 384 }
 385
 386 /* Allocation / deallocation. */
 387
 388 inline void
 389 _hb_buffer_allocate_unicode_vars (hb_buffer_t *buffer)
 390 {
 391   HB_BUFFER_ALLOCATE_VAR (buffer, unicode_props0);
 392   HB_BUFFER_ALLOCATE_VAR (buffer, unicode_props1);
 393 }
 394
 395 inline void
 396 _hb_buffer_deallocate_unicode_vars (hb_buffer_t *buffer)
 397 {
 398   HB_BUFFER_DEALLOCATE_VAR (buffer, unicode_props0);
 399   HB_BUFFER_DEALLOCATE_VAR (buffer, unicode_props1);
 400 }
 401
 402 inline void
 403 _hb_buffer_allocate_gsubgpos_vars (hb_buffer_t *buffer)
 404 {
 405   HB_BUFFER_ALLOCATE_VAR (buffer, glyph_props);
 406   HB_BUFFER_ALLOCATE_VAR (buffer, lig_props);
 407   HB_BUFFER_ALLOCATE_VAR (buffer, syllable);
 408 }
 409
 410 inline void
 411 _hb_buffer_deallocate_gsubgpos_vars (hb_buffer_t *buffer)
 412 {
 413   HB_BUFFER_DEALLOCATE_VAR (buffer, syllable);
 414   HB_BUFFER_DEALLOCATE_VAR (buffer, lig_props);
 415   HB_BUFFER_DEALLOCATE_VAR (buffer, glyph_props);
 416 }
 417
 418 /* Make sure no one directly touches our props... */
 419 #undef unicode_props0
 420 #undef unicode_props1
 421 #undef lig_props
 422 #undef glyph_props
 423
 424
 425 #endif /* HB_OT_LAYOUT_PRIVATE_HH */