1/*
2 * Copyright © 2007,2008,2009,2010  Red Hat, Inc.
3 * Copyright © 2010,2012,2013  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_GSUB_TABLE_HH
30#define HB_OT_LAYOUT_GSUB_TABLE_HH
31
32#include "hb-ot-layout-gsubgpos-private.hh"
33
34
35namespace OT {
36
37
38struct SingleSubstFormat1
39{
40  inline void closure (hb_closure_context_t *c) const
41  {
42    TRACE_CLOSURE (this);
43    Coverage::Iter iter;
44    for (iter.init (this+coverage); iter.more (); iter.next ()) {
45      hb_codepoint_t glyph_id = iter.get_glyph ();
46      if (c->glyphs->has (glyph_id))
47	c->glyphs->add ((glyph_id + deltaGlyphID) & 0xFFFF);
48    }
49  }
50
51  inline void collect_glyphs (hb_collect_glyphs_context_t *c) const
52  {
53    TRACE_COLLECT_GLYPHS (this);
54    Coverage::Iter iter;
55    for (iter.init (this+coverage); iter.more (); iter.next ()) {
56      hb_codepoint_t glyph_id = iter.get_glyph ();
57      c->input->add (glyph_id);
58      c->output->add ((glyph_id + deltaGlyphID) & 0xFFFF);
59    }
60  }
61
62  inline const Coverage &get_coverage (void) const
63  {
64    return this+coverage;
65  }
66
67  inline bool would_apply (hb_would_apply_context_t *c) const
68  {
69    TRACE_WOULD_APPLY (this);
70    return TRACE_RETURN (c->len == 1 && (this+coverage).get_coverage (c->glyphs[0]) != NOT_COVERED);
71  }
72
73  inline bool apply (hb_apply_context_t *c) const
74  {
75    TRACE_APPLY (this);
76    hb_codepoint_t glyph_id = c->buffer->cur().codepoint;
77    unsigned int index = (this+coverage).get_coverage (glyph_id);
78    if (likely (index == NOT_COVERED)) return TRACE_RETURN (false);
79
80    /* According to the Adobe Annotated OpenType Suite, result is always
81     * limited to 16bit. */
82    glyph_id = (glyph_id + deltaGlyphID) & 0xFFFF;
83    c->replace_glyph (glyph_id);
84
85    return TRACE_RETURN (true);
86  }
87
88  inline bool serialize (hb_serialize_context_t *c,
89			 Supplier<GlyphID> &glyphs,
90			 unsigned int num_glyphs,
91			 int delta)
92  {
93    TRACE_SERIALIZE (this);
94    if (unlikely (!c->extend_min (*this))) return TRACE_RETURN (false);
95    if (unlikely (!coverage.serialize (c, this).serialize (c, glyphs, num_glyphs))) return TRACE_RETURN (false);
96    deltaGlyphID.set (delta); /* TODO(serilaize) overflow? */
97    return TRACE_RETURN (true);
98  }
99
100  inline bool sanitize (hb_sanitize_context_t *c) {
101    TRACE_SANITIZE (this);
102    return TRACE_RETURN (coverage.sanitize (c, this) && deltaGlyphID.sanitize (c));
103  }
104
105  protected:
106  USHORT	format;			/* Format identifier--format = 1 */
107  OffsetTo<Coverage>
108		coverage;		/* Offset to Coverage table--from
109					 * beginning of Substitution table */
110  SHORT		deltaGlyphID;		/* Add to original GlyphID to get
111					 * substitute GlyphID */
112  public:
113  DEFINE_SIZE_STATIC (6);
114};
115
116struct SingleSubstFormat2
117{
118  inline void closure (hb_closure_context_t *c) const
119  {
120    TRACE_CLOSURE (this);
121    Coverage::Iter iter;
122    for (iter.init (this+coverage); iter.more (); iter.next ()) {
123      if (c->glyphs->has (iter.get_glyph ()))
124	c->glyphs->add (substitute[iter.get_coverage ()]);
125    }
126  }
127
128  inline void collect_glyphs (hb_collect_glyphs_context_t *c) const
129  {
130    TRACE_COLLECT_GLYPHS (this);
131    Coverage::Iter iter;
132    for (iter.init (this+coverage); iter.more (); iter.next ()) {
133      c->input->add (iter.get_glyph ());
134      c->output->add (substitute[iter.get_coverage ()]);
135    }
136  }
137
138  inline const Coverage &get_coverage (void) const
139  {
140    return this+coverage;
141  }
142
143  inline bool would_apply (hb_would_apply_context_t *c) const
144  {
145    TRACE_WOULD_APPLY (this);
146    return TRACE_RETURN (c->len == 1 && (this+coverage).get_coverage (c->glyphs[0]) != NOT_COVERED);
147  }
148
149  inline bool apply (hb_apply_context_t *c) const
150  {
151    TRACE_APPLY (this);
152    hb_codepoint_t glyph_id = c->buffer->cur().codepoint;
153    unsigned int index = (this+coverage).get_coverage (glyph_id);
154    if (likely (index == NOT_COVERED)) return TRACE_RETURN (false);
155
156    if (unlikely (index >= substitute.len)) return TRACE_RETURN (false);
157
158    glyph_id = substitute[index];
159    c->replace_glyph (glyph_id);
160
161    return TRACE_RETURN (true);
162  }
163
164  inline bool serialize (hb_serialize_context_t *c,
165			 Supplier<GlyphID> &glyphs,
166			 Supplier<GlyphID> &substitutes,
167			 unsigned int num_glyphs)
168  {
169    TRACE_SERIALIZE (this);
170    if (unlikely (!c->extend_min (*this))) return TRACE_RETURN (false);
171    if (unlikely (!substitute.serialize (c, substitutes, num_glyphs))) return TRACE_RETURN (false);
172    if (unlikely (!coverage.serialize (c, this).serialize (c, glyphs, num_glyphs))) return TRACE_RETURN (false);
173    return TRACE_RETURN (true);
174  }
175
176  inline bool sanitize (hb_sanitize_context_t *c) {
177    TRACE_SANITIZE (this);
178    return TRACE_RETURN (coverage.sanitize (c, this) && substitute.sanitize (c));
179  }
180
181  protected:
182  USHORT	format;			/* Format identifier--format = 2 */
183  OffsetTo<Coverage>
184		coverage;		/* Offset to Coverage table--from
185					 * beginning of Substitution table */
186  ArrayOf<GlyphID>
187		substitute;		/* Array of substitute
188					 * GlyphIDs--ordered by Coverage Index */
189  public:
190  DEFINE_SIZE_ARRAY (6, substitute);
191};
192
193struct SingleSubst
194{
195  inline bool serialize (hb_serialize_context_t *c,
196			 Supplier<GlyphID> &glyphs,
197			 Supplier<GlyphID> &substitutes,
198			 unsigned int num_glyphs)
199  {
200    TRACE_SERIALIZE (this);
201    if (unlikely (!c->extend_min (u.format))) return TRACE_RETURN (false);
202    unsigned int format = 2;
203    int delta;
204    if (num_glyphs) {
205      format = 1;
206      /* TODO(serialize) check for wrap-around */
207      delta = substitutes[0] - glyphs[0];
208      for (unsigned int i = 1; i < num_glyphs; i++)
209	if (delta != substitutes[i] - glyphs[i]) {
210	  format = 2;
211	  break;
212	}
213    }
214    u.format.set (format);
215    switch (u.format) {
216    case 1: return TRACE_RETURN (u.format1.serialize (c, glyphs, num_glyphs, delta));
217    case 2: return TRACE_RETURN (u.format2.serialize (c, glyphs, substitutes, num_glyphs));
218    default:return TRACE_RETURN (false);
219    }
220  }
221
222  template <typename context_t>
223  inline typename context_t::return_t dispatch (context_t *c) const
224  {
225    TRACE_DISPATCH (this);
226    switch (u.format) {
227    case 1: return TRACE_RETURN (c->dispatch (u.format1));
228    case 2: return TRACE_RETURN (c->dispatch (u.format2));
229    default:return TRACE_RETURN (c->default_return_value ());
230    }
231  }
232
233  inline bool sanitize (hb_sanitize_context_t *c) {
234    TRACE_SANITIZE (this);
235    if (!u.format.sanitize (c)) return TRACE_RETURN (false);
236    switch (u.format) {
237    case 1: return TRACE_RETURN (u.format1.sanitize (c));
238    case 2: return TRACE_RETURN (u.format2.sanitize (c));
239    default:return TRACE_RETURN (true);
240    }
241  }
242
243  protected:
244  union {
245  USHORT		format;		/* Format identifier */
246  SingleSubstFormat1	format1;
247  SingleSubstFormat2	format2;
248  } u;
249};
250
251
252struct Sequence
253{
254  inline void closure (hb_closure_context_t *c) const
255  {
256    TRACE_CLOSURE (this);
257    unsigned int count = substitute.len;
258    for (unsigned int i = 0; i < count; i++)
259      c->glyphs->add (substitute[i]);
260  }
261
262  inline void collect_glyphs (hb_collect_glyphs_context_t *c) const
263  {
264    TRACE_COLLECT_GLYPHS (this);
265    unsigned int count = substitute.len;
266    for (unsigned int i = 0; i < count; i++)
267      c->output->add (substitute[i]);
268  }
269
270  inline bool apply (hb_apply_context_t *c) const
271  {
272    TRACE_APPLY (this);
273    if (unlikely (!substitute.len)) return TRACE_RETURN (false);
274
275    unsigned int klass = _hb_glyph_info_is_ligature (&c->buffer->cur()) ?
276			 HB_OT_LAYOUT_GLYPH_PROPS_BASE_GLYPH : 0;
277    unsigned int count = substitute.len;
278    if (count == 1) /* Special-case to make it in-place. */
279    {
280      c->replace_glyph (substitute.array[0]);
281    }
282    else
283    {
284      for (unsigned int i = 0; i < count; i++) {
285	_hb_glyph_info_set_lig_props_for_component (&c->buffer->cur(), i);
286	c->output_glyph (substitute.array[i], klass);
287      }
288      c->buffer->skip_glyph ();
289    }
290
291    return TRACE_RETURN (true);
292  }
293
294  inline bool serialize (hb_serialize_context_t *c,
295			 Supplier<GlyphID> &glyphs,
296			 unsigned int num_glyphs)
297  {
298    TRACE_SERIALIZE (this);
299    if (unlikely (!c->extend_min (*this))) return TRACE_RETURN (false);
300    if (unlikely (!substitute.serialize (c, glyphs, num_glyphs))) return TRACE_RETURN (false);
301    return TRACE_RETURN (true);
302  }
303
304  inline bool sanitize (hb_sanitize_context_t *c) {
305    TRACE_SANITIZE (this);
306    return TRACE_RETURN (substitute.sanitize (c));
307  }
308
309  protected:
310  ArrayOf<GlyphID>
311		substitute;		/* String of GlyphIDs to substitute */
312  public:
313  DEFINE_SIZE_ARRAY (2, substitute);
314};
315
316struct MultipleSubstFormat1
317{
318  inline void closure (hb_closure_context_t *c) const
319  {
320    TRACE_CLOSURE (this);
321    Coverage::Iter iter;
322    for (iter.init (this+coverage); iter.more (); iter.next ()) {
323      if (c->glyphs->has (iter.get_glyph ()))
324	(this+sequence[iter.get_coverage ()]).closure (c);
325    }
326  }
327
328  inline void collect_glyphs (hb_collect_glyphs_context_t *c) const
329  {
330    TRACE_COLLECT_GLYPHS (this);
331    (this+coverage).add_coverage (c->input);
332    unsigned int count = sequence.len;
333    for (unsigned int i = 0; i < count; i++)
334	(this+sequence[i]).collect_glyphs (c);
335  }
336
337  inline const Coverage &get_coverage (void) const
338  {
339    return this+coverage;
340  }
341
342  inline bool would_apply (hb_would_apply_context_t *c) const
343  {
344    TRACE_WOULD_APPLY (this);
345    return TRACE_RETURN (c->len == 1 && (this+coverage).get_coverage (c->glyphs[0]) != NOT_COVERED);
346  }
347
348  inline bool apply (hb_apply_context_t *c) const
349  {
350    TRACE_APPLY (this);
351
352    unsigned int index = (this+coverage).get_coverage (c->buffer->cur().codepoint);
353    if (likely (index == NOT_COVERED)) return TRACE_RETURN (false);
354
355    return TRACE_RETURN ((this+sequence[index]).apply (c));
356  }
357
358  inline bool serialize (hb_serialize_context_t *c,
359			 Supplier<GlyphID> &glyphs,
360			 Supplier<unsigned int> &substitute_len_list,
361			 unsigned int num_glyphs,
362			 Supplier<GlyphID> &substitute_glyphs_list)
363  {
364    TRACE_SERIALIZE (this);
365    if (unlikely (!c->extend_min (*this))) return TRACE_RETURN (false);
366    if (unlikely (!sequence.serialize (c, num_glyphs))) return TRACE_RETURN (false);
367    for (unsigned int i = 0; i < num_glyphs; i++)
368      if (unlikely (!sequence[i].serialize (c, this).serialize (c,
369								substitute_glyphs_list,
370								substitute_len_list[i]))) return TRACE_RETURN (false);
371    substitute_len_list.advance (num_glyphs);
372    if (unlikely (!coverage.serialize (c, this).serialize (c, glyphs, num_glyphs))) return TRACE_RETURN (false);
373    return TRACE_RETURN (true);
374  }
375
376  inline bool sanitize (hb_sanitize_context_t *c) {
377    TRACE_SANITIZE (this);
378    return TRACE_RETURN (coverage.sanitize (c, this) && sequence.sanitize (c, this));
379  }
380
381  protected:
382  USHORT	format;			/* Format identifier--format = 1 */
383  OffsetTo<Coverage>
384		coverage;		/* Offset to Coverage table--from
385					 * beginning of Substitution table */
386  OffsetArrayOf<Sequence>
387		sequence;		/* Array of Sequence tables
388					 * ordered by Coverage Index */
389  public:
390  DEFINE_SIZE_ARRAY (6, sequence);
391};
392
393struct MultipleSubst
394{
395  inline bool serialize (hb_serialize_context_t *c,
396			 Supplier<GlyphID> &glyphs,
397			 Supplier<unsigned int> &substitute_len_list,
398			 unsigned int num_glyphs,
399			 Supplier<GlyphID> &substitute_glyphs_list)
400  {
401    TRACE_SERIALIZE (this);
402    if (unlikely (!c->extend_min (u.format))) return TRACE_RETURN (false);
403    unsigned int format = 1;
404    u.format.set (format);
405    switch (u.format) {
406    case 1: return TRACE_RETURN (u.format1.serialize (c, glyphs, substitute_len_list, num_glyphs, substitute_glyphs_list));
407    default:return TRACE_RETURN (false);
408    }
409  }
410
411  template <typename context_t>
412  inline typename context_t::return_t dispatch (context_t *c) const
413  {
414    TRACE_DISPATCH (this);
415    switch (u.format) {
416    case 1: return TRACE_RETURN (c->dispatch (u.format1));
417    default:return TRACE_RETURN (c->default_return_value ());
418    }
419  }
420
421  inline bool sanitize (hb_sanitize_context_t *c) {
422    TRACE_SANITIZE (this);
423    if (!u.format.sanitize (c)) return TRACE_RETURN (false);
424    switch (u.format) {
425    case 1: return TRACE_RETURN (u.format1.sanitize (c));
426    default:return TRACE_RETURN (true);
427    }
428  }
429
430  protected:
431  union {
432  USHORT		format;		/* Format identifier */
433  MultipleSubstFormat1	format1;
434  } u;
435};
436
437
438typedef ArrayOf<GlyphID> AlternateSet;	/* Array of alternate GlyphIDs--in
439					 * arbitrary order */
440
441struct AlternateSubstFormat1
442{
443  inline void closure (hb_closure_context_t *c) const
444  {
445    TRACE_CLOSURE (this);
446    Coverage::Iter iter;
447    for (iter.init (this+coverage); iter.more (); iter.next ()) {
448      if (c->glyphs->has (iter.get_glyph ())) {
449	const AlternateSet &alt_set = this+alternateSet[iter.get_coverage ()];
450	unsigned int count = alt_set.len;
451	for (unsigned int i = 0; i < count; i++)
452	  c->glyphs->add (alt_set[i]);
453      }
454    }
455  }
456
457  inline void collect_glyphs (hb_collect_glyphs_context_t *c) const
458  {
459    TRACE_COLLECT_GLYPHS (this);
460    Coverage::Iter iter;
461    for (iter.init (this+coverage); iter.more (); iter.next ()) {
462      c->input->add (iter.get_glyph ());
463      const AlternateSet &alt_set = this+alternateSet[iter.get_coverage ()];
464      unsigned int count = alt_set.len;
465      for (unsigned int i = 0; i < count; i++)
466	c->output->add (alt_set[i]);
467    }
468  }
469
470  inline const Coverage &get_coverage (void) const
471  {
472    return this+coverage;
473  }
474
475  inline bool would_apply (hb_would_apply_context_t *c) const
476  {
477    TRACE_WOULD_APPLY (this);
478    return TRACE_RETURN (c->len == 1 && (this+coverage).get_coverage (c->glyphs[0]) != NOT_COVERED);
479  }
480
481  inline bool apply (hb_apply_context_t *c) const
482  {
483    TRACE_APPLY (this);
484    hb_codepoint_t glyph_id = c->buffer->cur().codepoint;
485
486    unsigned int index = (this+coverage).get_coverage (glyph_id);
487    if (likely (index == NOT_COVERED)) return TRACE_RETURN (false);
488
489    const AlternateSet &alt_set = this+alternateSet[index];
490
491    if (unlikely (!alt_set.len)) return TRACE_RETURN (false);
492
493    hb_mask_t glyph_mask = c->buffer->cur().mask;
494    hb_mask_t lookup_mask = c->lookup_mask;
495
496    /* Note: This breaks badly if two features enabled this lookup together. */
497    unsigned int shift = _hb_ctz (lookup_mask);
498    unsigned int alt_index = ((lookup_mask & glyph_mask) >> shift);
499
500    if (unlikely (alt_index > alt_set.len || alt_index == 0)) return TRACE_RETURN (false);
501
502    glyph_id = alt_set[alt_index - 1];
503
504    c->replace_glyph (glyph_id);
505
506    return TRACE_RETURN (true);
507  }
508
509  inline bool serialize (hb_serialize_context_t *c,
510			 Supplier<GlyphID> &glyphs,
511			 Supplier<unsigned int> &alternate_len_list,
512			 unsigned int num_glyphs,
513			 Supplier<GlyphID> &alternate_glyphs_list)
514  {
515    TRACE_SERIALIZE (this);
516    if (unlikely (!c->extend_min (*this))) return TRACE_RETURN (false);
517    if (unlikely (!alternateSet.serialize (c, num_glyphs))) return TRACE_RETURN (false);
518    for (unsigned int i = 0; i < num_glyphs; i++)
519      if (unlikely (!alternateSet[i].serialize (c, this).serialize (c,
520								    alternate_glyphs_list,
521								    alternate_len_list[i]))) return TRACE_RETURN (false);
522    alternate_len_list.advance (num_glyphs);
523    if (unlikely (!coverage.serialize (c, this).serialize (c, glyphs, num_glyphs))) return TRACE_RETURN (false);
524    return TRACE_RETURN (true);
525  }
526
527  inline bool sanitize (hb_sanitize_context_t *c) {
528    TRACE_SANITIZE (this);
529    return TRACE_RETURN (coverage.sanitize (c, this) && alternateSet.sanitize (c, this));
530  }
531
532  protected:
533  USHORT	format;			/* Format identifier--format = 1 */
534  OffsetTo<Coverage>
535		coverage;		/* Offset to Coverage table--from
536					 * beginning of Substitution table */
537  OffsetArrayOf<AlternateSet>
538		alternateSet;		/* Array of AlternateSet tables
539					 * ordered by Coverage Index */
540  public:
541  DEFINE_SIZE_ARRAY (6, alternateSet);
542};
543
544struct AlternateSubst
545{
546  inline bool serialize (hb_serialize_context_t *c,
547			 Supplier<GlyphID> &glyphs,
548			 Supplier<unsigned int> &alternate_len_list,
549			 unsigned int num_glyphs,
550			 Supplier<GlyphID> &alternate_glyphs_list)
551  {
552    TRACE_SERIALIZE (this);
553    if (unlikely (!c->extend_min (u.format))) return TRACE_RETURN (false);
554    unsigned int format = 1;
555    u.format.set (format);
556    switch (u.format) {
557    case 1: return TRACE_RETURN (u.format1.serialize (c, glyphs, alternate_len_list, num_glyphs, alternate_glyphs_list));
558    default:return TRACE_RETURN (false);
559    }
560  }
561
562  template <typename context_t>
563  inline typename context_t::return_t dispatch (context_t *c) const
564  {
565    TRACE_DISPATCH (this);
566    switch (u.format) {
567    case 1: return TRACE_RETURN (c->dispatch (u.format1));
568    default:return TRACE_RETURN (c->default_return_value ());
569    }
570  }
571
572  inline bool sanitize (hb_sanitize_context_t *c) {
573    TRACE_SANITIZE (this);
574    if (!u.format.sanitize (c)) return TRACE_RETURN (false);
575    switch (u.format) {
576    case 1: return TRACE_RETURN (u.format1.sanitize (c));
577    default:return TRACE_RETURN (true);
578    }
579  }
580
581  protected:
582  union {
583  USHORT		format;		/* Format identifier */
584  AlternateSubstFormat1	format1;
585  } u;
586};
587
588
589struct Ligature
590{
591  inline void closure (hb_closure_context_t *c) const
592  {
593    TRACE_CLOSURE (this);
594    unsigned int count = component.len;
595    for (unsigned int i = 1; i < count; i++)
596      if (!c->glyphs->has (component[i]))
597        return;
598    c->glyphs->add (ligGlyph);
599  }
600
601  inline void collect_glyphs (hb_collect_glyphs_context_t *c) const
602  {
603    TRACE_COLLECT_GLYPHS (this);
604    unsigned int count = component.len;
605    for (unsigned int i = 1; i < count; i++)
606      c->input->add (component[i]);
607    c->output->add (ligGlyph);
608  }
609
610  inline bool would_apply (hb_would_apply_context_t *c) const
611  {
612    TRACE_WOULD_APPLY (this);
613    if (c->len != component.len)
614      return TRACE_RETURN (false);
615
616    for (unsigned int i = 1; i < c->len; i++)
617      if (likely (c->glyphs[i] != component[i]))
618	return TRACE_RETURN (false);
619
620    return TRACE_RETURN (true);
621  }
622
623  inline bool apply (hb_apply_context_t *c) const
624  {
625    TRACE_APPLY (this);
626    unsigned int count = component.len;
627    if (unlikely (count < 1)) return TRACE_RETURN (false);
628
629    bool is_mark_ligature = false;
630    unsigned int total_component_count = 0;
631
632    unsigned int match_length = 0;
633    unsigned int match_positions[MAX_CONTEXT_LENGTH];
634
635    if (likely (!match_input (c, count,
636			      &component[1],
637			      match_glyph,
638			      NULL,
639			      &match_length,
640			      match_positions,
641			      &is_mark_ligature,
642			      &total_component_count)))
643      return TRACE_RETURN (false);
644
645    ligate_input (c,
646		  count,
647		  match_positions,
648		  match_length,
649		  ligGlyph,
650		  is_mark_ligature,
651		  total_component_count);
652
653    return TRACE_RETURN (true);
654  }
655
656  inline bool serialize (hb_serialize_context_t *c,
657			 GlyphID ligature,
658			 Supplier<GlyphID> &components, /* Starting from second */
659			 unsigned int num_components /* Including first component */)
660  {
661    TRACE_SERIALIZE (this);
662    if (unlikely (!c->extend_min (*this))) return TRACE_RETURN (false);
663    ligGlyph = ligature;
664    if (unlikely (!component.serialize (c, components, num_components))) return TRACE_RETURN (false);
665    return TRACE_RETURN (true);
666  }
667
668  public:
669  inline bool sanitize (hb_sanitize_context_t *c) {
670    TRACE_SANITIZE (this);
671    return TRACE_RETURN (ligGlyph.sanitize (c) && component.sanitize (c));
672  }
673
674  protected:
675  GlyphID	ligGlyph;		/* GlyphID of ligature to substitute */
676  HeadlessArrayOf<GlyphID>
677		component;		/* Array of component GlyphIDs--start
678					 * with the second  component--ordered
679					 * in writing direction */
680  public:
681  DEFINE_SIZE_ARRAY (4, component);
682};
683
684struct LigatureSet
685{
686  inline void closure (hb_closure_context_t *c) const
687  {
688    TRACE_CLOSURE (this);
689    unsigned int num_ligs = ligature.len;
690    for (unsigned int i = 0; i < num_ligs; i++)
691      (this+ligature[i]).closure (c);
692  }
693
694  inline void collect_glyphs (hb_collect_glyphs_context_t *c) const
695  {
696    TRACE_COLLECT_GLYPHS (this);
697    unsigned int num_ligs = ligature.len;
698    for (unsigned int i = 0; i < num_ligs; i++)
699      (this+ligature[i]).collect_glyphs (c);
700  }
701
702  inline bool would_apply (hb_would_apply_context_t *c) const
703  {
704    TRACE_WOULD_APPLY (this);
705    unsigned int num_ligs = ligature.len;
706    for (unsigned int i = 0; i < num_ligs; i++)
707    {
708      const Ligature &lig = this+ligature[i];
709      if (lig.would_apply (c))
710        return TRACE_RETURN (true);
711    }
712    return TRACE_RETURN (false);
713  }
714
715  inline bool apply (hb_apply_context_t *c) const
716  {
717    TRACE_APPLY (this);
718    unsigned int num_ligs = ligature.len;
719    for (unsigned int i = 0; i < num_ligs; i++)
720    {
721      const Ligature &lig = this+ligature[i];
722      if (lig.apply (c)) return TRACE_RETURN (true);
723    }
724
725    return TRACE_RETURN (false);
726  }
727
728  inline bool serialize (hb_serialize_context_t *c,
729			 Supplier<GlyphID> &ligatures,
730			 Supplier<unsigned int> &component_count_list,
731			 unsigned int num_ligatures,
732			 Supplier<GlyphID> &component_list /* Starting from second for each ligature */)
733  {
734    TRACE_SERIALIZE (this);
735    if (unlikely (!c->extend_min (*this))) return TRACE_RETURN (false);
736    if (unlikely (!ligature.serialize (c, num_ligatures))) return TRACE_RETURN (false);
737    for (unsigned int i = 0; i < num_ligatures; i++)
738      if (unlikely (!ligature[i].serialize (c, this).serialize (c,
739								ligatures[i],
740								component_list,
741								component_count_list[i]))) return TRACE_RETURN (false);
742    ligatures.advance (num_ligatures);
743    component_count_list.advance (num_ligatures);
744    return TRACE_RETURN (true);
745  }
746
747  inline bool sanitize (hb_sanitize_context_t *c) {
748    TRACE_SANITIZE (this);
749    return TRACE_RETURN (ligature.sanitize (c, this));
750  }
751
752  protected:
753  OffsetArrayOf<Ligature>
754		ligature;		/* Array LigatureSet tables
755					 * ordered by preference */
756  public:
757  DEFINE_SIZE_ARRAY (2, ligature);
758};
759
760struct LigatureSubstFormat1
761{
762  inline void closure (hb_closure_context_t *c) const
763  {
764    TRACE_CLOSURE (this);
765    Coverage::Iter iter;
766    for (iter.init (this+coverage); iter.more (); iter.next ()) {
767      if (c->glyphs->has (iter.get_glyph ()))
768	(this+ligatureSet[iter.get_coverage ()]).closure (c);
769    }
770  }
771
772  inline void collect_glyphs (hb_collect_glyphs_context_t *c) const
773  {
774    TRACE_COLLECT_GLYPHS (this);
775    Coverage::Iter iter;
776    for (iter.init (this+coverage); iter.more (); iter.next ()) {
777      c->input->add (iter.get_glyph ());
778      (this+ligatureSet[iter.get_coverage ()]).collect_glyphs (c);
779    }
780  }
781
782  inline const Coverage &get_coverage (void) const
783  {
784    return this+coverage;
785  }
786
787  inline bool would_apply (hb_would_apply_context_t *c) const
788  {
789    TRACE_WOULD_APPLY (this);
790    unsigned int index = (this+coverage).get_coverage (c->glyphs[0]);
791    if (likely (index == NOT_COVERED)) return TRACE_RETURN (false);
792
793    const LigatureSet &lig_set = this+ligatureSet[index];
794    return TRACE_RETURN (lig_set.would_apply (c));
795  }
796
797  inline bool apply (hb_apply_context_t *c) const
798  {
799    TRACE_APPLY (this);
800    hb_codepoint_t glyph_id = c->buffer->cur().codepoint;
801
802    unsigned int index = (this+coverage).get_coverage (glyph_id);
803    if (likely (index == NOT_COVERED)) return TRACE_RETURN (false);
804
805    const LigatureSet &lig_set = this+ligatureSet[index];
806    return TRACE_RETURN (lig_set.apply (c));
807  }
808
809  inline bool serialize (hb_serialize_context_t *c,
810			 Supplier<GlyphID> &first_glyphs,
811			 Supplier<unsigned int> &ligature_per_first_glyph_count_list,
812			 unsigned int num_first_glyphs,
813			 Supplier<GlyphID> &ligatures_list,
814			 Supplier<unsigned int> &component_count_list,
815			 Supplier<GlyphID> &component_list /* Starting from second for each ligature */)
816  {
817    TRACE_SERIALIZE (this);
818    if (unlikely (!c->extend_min (*this))) return TRACE_RETURN (false);
819    if (unlikely (!ligatureSet.serialize (c, num_first_glyphs))) return TRACE_RETURN (false);
820    for (unsigned int i = 0; i < num_first_glyphs; i++)
821      if (unlikely (!ligatureSet[i].serialize (c, this).serialize (c,
822								   ligatures_list,
823								   component_count_list,
824								   ligature_per_first_glyph_count_list[i],
825								   component_list))) return TRACE_RETURN (false);
826    ligature_per_first_glyph_count_list.advance (num_first_glyphs);
827    if (unlikely (!coverage.serialize (c, this).serialize (c, first_glyphs, num_first_glyphs))) return TRACE_RETURN (false);
828    return TRACE_RETURN (true);
829  }
830
831  inline bool sanitize (hb_sanitize_context_t *c) {
832    TRACE_SANITIZE (this);
833    return TRACE_RETURN (coverage.sanitize (c, this) && ligatureSet.sanitize (c, this));
834  }
835
836  protected:
837  USHORT	format;			/* Format identifier--format = 1 */
838  OffsetTo<Coverage>
839		coverage;		/* Offset to Coverage table--from
840					 * beginning of Substitution table */
841  OffsetArrayOf<LigatureSet>
842		ligatureSet;		/* Array LigatureSet tables
843					 * ordered by Coverage Index */
844  public:
845  DEFINE_SIZE_ARRAY (6, ligatureSet);
846};
847
848struct LigatureSubst
849{
850  inline bool serialize (hb_serialize_context_t *c,
851			 Supplier<GlyphID> &first_glyphs,
852			 Supplier<unsigned int> &ligature_per_first_glyph_count_list,
853			 unsigned int num_first_glyphs,
854			 Supplier<GlyphID> &ligatures_list,
855			 Supplier<unsigned int> &component_count_list,
856			 Supplier<GlyphID> &component_list /* Starting from second for each ligature */)
857  {
858    TRACE_SERIALIZE (this);
859    if (unlikely (!c->extend_min (u.format))) return TRACE_RETURN (false);
860    unsigned int format = 1;
861    u.format.set (format);
862    switch (u.format) {
863    case 1: return TRACE_RETURN (u.format1.serialize (c, first_glyphs, ligature_per_first_glyph_count_list, num_first_glyphs,
864						      ligatures_list, component_count_list, component_list));
865    default:return TRACE_RETURN (false);
866    }
867  }
868
869  template <typename context_t>
870  inline typename context_t::return_t dispatch (context_t *c) const
871  {
872    TRACE_DISPATCH (this);
873    switch (u.format) {
874    case 1: return TRACE_RETURN (c->dispatch (u.format1));
875    default:return TRACE_RETURN (c->default_return_value ());
876    }
877  }
878
879  inline bool sanitize (hb_sanitize_context_t *c) {
880    TRACE_SANITIZE (this);
881    if (!u.format.sanitize (c)) return TRACE_RETURN (false);
882    switch (u.format) {
883    case 1: return TRACE_RETURN (u.format1.sanitize (c));
884    default:return TRACE_RETURN (true);
885    }
886  }
887
888  protected:
889  union {
890  USHORT		format;		/* Format identifier */
891  LigatureSubstFormat1	format1;
892  } u;
893};
894
895
896struct ContextSubst : Context {};
897
898struct ChainContextSubst : ChainContext {};
899
900struct ExtensionSubst : Extension<ExtensionSubst>
901{
902  typedef struct SubstLookupSubTable LookupSubTable;
903
904  inline bool is_reverse (void) const;
905};
906
907
908struct ReverseChainSingleSubstFormat1
909{
910  inline void closure (hb_closure_context_t *c) const
911  {
912    TRACE_CLOSURE (this);
913    const OffsetArrayOf<Coverage> &lookahead = StructAfter<OffsetArrayOf<Coverage> > (backtrack);
914
915    unsigned int count;
916
917    count = backtrack.len;
918    for (unsigned int i = 0; i < count; i++)
919      if (!(this+backtrack[i]).intersects (c->glyphs))
920        return;
921
922    count = lookahead.len;
923    for (unsigned int i = 0; i < count; i++)
924      if (!(this+lookahead[i]).intersects (c->glyphs))
925        return;
926
927    const ArrayOf<GlyphID> &substitute = StructAfter<ArrayOf<GlyphID> > (lookahead);
928    Coverage::Iter iter;
929    for (iter.init (this+coverage); iter.more (); iter.next ()) {
930      if (c->glyphs->has (iter.get_glyph ()))
931	c->glyphs->add (substitute[iter.get_coverage ()]);
932    }
933  }
934
935  inline void collect_glyphs (hb_collect_glyphs_context_t *c) const
936  {
937    TRACE_COLLECT_GLYPHS (this);
938
939    const OffsetArrayOf<Coverage> &lookahead = StructAfter<OffsetArrayOf<Coverage> > (backtrack);
940
941    unsigned int count;
942
943    (this+coverage).add_coverage (c->input);
944
945    count = backtrack.len;
946    for (unsigned int i = 0; i < count; i++)
947      (this+backtrack[i]).add_coverage (c->before);
948
949    count = lookahead.len;
950    for (unsigned int i = 0; i < count; i++)
951      (this+lookahead[i]).add_coverage (c->after);
952
953    const ArrayOf<GlyphID> &substitute = StructAfter<ArrayOf<GlyphID> > (lookahead);
954    count = substitute.len;
955    for (unsigned int i = 0; i < count; i++)
956      c->output->add (substitute[i]);
957  }
958
959  inline const Coverage &get_coverage (void) const
960  {
961    return this+coverage;
962  }
963
964  inline bool would_apply (hb_would_apply_context_t *c) const
965  {
966    TRACE_WOULD_APPLY (this);
967    return TRACE_RETURN (c->len == 1 && (this+coverage).get_coverage (c->glyphs[0]) != NOT_COVERED);
968  }
969
970  inline bool apply (hb_apply_context_t *c) const
971  {
972    TRACE_APPLY (this);
973    if (unlikely (c->nesting_level_left != MAX_NESTING_LEVEL))
974      return TRACE_RETURN (false); /* No chaining to this type */
975
976    unsigned int index = (this+coverage).get_coverage (c->buffer->cur().codepoint);
977    if (likely (index == NOT_COVERED)) return TRACE_RETURN (false);
978
979    const OffsetArrayOf<Coverage> &lookahead = StructAfter<OffsetArrayOf<Coverage> > (backtrack);
980    const ArrayOf<GlyphID> &substitute = StructAfter<ArrayOf<GlyphID> > (lookahead);
981
982    if (match_backtrack (c,
983			 backtrack.len, (USHORT *) backtrack.array,
984			 match_coverage, this) &&
985        match_lookahead (c,
986			 lookahead.len, (USHORT *) lookahead.array,
987			 match_coverage, this,
988			 1))
989    {
990      c->replace_glyph_inplace (substitute[index]);
991      /* Note: We DON'T decrease buffer->idx.  The main loop does it
992       * for us.  This is useful for preventing surprises if someone
993       * calls us through a Context lookup. */
994      return TRACE_RETURN (true);
995    }
996
997    return TRACE_RETURN (false);
998  }
999
1000  inline bool sanitize (hb_sanitize_context_t *c) {
1001    TRACE_SANITIZE (this);
1002    if (!(coverage.sanitize (c, this) && backtrack.sanitize (c, this)))
1003      return TRACE_RETURN (false);
1004    OffsetArrayOf<Coverage> &lookahead = StructAfter<OffsetArrayOf<Coverage> > (backtrack);
1005    if (!lookahead.sanitize (c, this))
1006      return TRACE_RETURN (false);
1007    ArrayOf<GlyphID> &substitute = StructAfter<ArrayOf<GlyphID> > (lookahead);
1008    return TRACE_RETURN (substitute.sanitize (c));
1009  }
1010
1011  protected:
1012  USHORT	format;			/* Format identifier--format = 1 */
1013  OffsetTo<Coverage>
1014		coverage;		/* Offset to Coverage table--from
1015					 * beginning of table */
1016  OffsetArrayOf<Coverage>
1017		backtrack;		/* Array of coverage tables
1018					 * in backtracking sequence, in  glyph
1019					 * sequence order */
1020  OffsetArrayOf<Coverage>
1021		lookaheadX;		/* Array of coverage tables
1022					 * in lookahead sequence, in glyph
1023					 * sequence order */
1024  ArrayOf<GlyphID>
1025		substituteX;		/* Array of substitute
1026					 * GlyphIDs--ordered by Coverage Index */
1027  public:
1028  DEFINE_SIZE_MIN (10);
1029};
1030
1031struct ReverseChainSingleSubst
1032{
1033  template <typename context_t>
1034  inline typename context_t::return_t dispatch (context_t *c) const
1035  {
1036    TRACE_DISPATCH (this);
1037    switch (u.format) {
1038    case 1: return TRACE_RETURN (c->dispatch (u.format1));
1039    default:return TRACE_RETURN (c->default_return_value ());
1040    }
1041  }
1042
1043  inline bool sanitize (hb_sanitize_context_t *c) {
1044    TRACE_SANITIZE (this);
1045    if (!u.format.sanitize (c)) return TRACE_RETURN (false);
1046    switch (u.format) {
1047    case 1: return TRACE_RETURN (u.format1.sanitize (c));
1048    default:return TRACE_RETURN (true);
1049    }
1050  }
1051
1052  protected:
1053  union {
1054  USHORT				format;		/* Format identifier */
1055  ReverseChainSingleSubstFormat1	format1;
1056  } u;
1057};
1058
1059
1060
1061/*
1062 * SubstLookup
1063 */
1064
1065struct SubstLookupSubTable
1066{
1067  friend struct SubstLookup;
1068
1069  enum Type {
1070    Single		= 1,
1071    Multiple		= 2,
1072    Alternate		= 3,
1073    Ligature		= 4,
1074    Context		= 5,
1075    ChainContext	= 6,
1076    Extension		= 7,
1077    ReverseChainSingle	= 8
1078  };
1079
1080  template <typename context_t>
1081  inline typename context_t::return_t dispatch (context_t *c, unsigned int lookup_type) const
1082  {
1083    TRACE_DISPATCH (this);
1084    switch (lookup_type) {
1085    case Single:		return TRACE_RETURN (u.single.dispatch (c));
1086    case Multiple:		return TRACE_RETURN (u.multiple.dispatch (c));
1087    case Alternate:		return TRACE_RETURN (u.alternate.dispatch (c));
1088    case Ligature:		return TRACE_RETURN (u.ligature.dispatch (c));
1089    case Context:		return TRACE_RETURN (u.context.dispatch (c));
1090    case ChainContext:		return TRACE_RETURN (u.chainContext.dispatch (c));
1091    case Extension:		return TRACE_RETURN (u.extension.dispatch (c));
1092    case ReverseChainSingle:	return TRACE_RETURN (u.reverseChainContextSingle.dispatch (c));
1093    default:			return TRACE_RETURN (c->default_return_value ());
1094    }
1095  }
1096
1097  inline bool sanitize (hb_sanitize_context_t *c, unsigned int lookup_type) {
1098    TRACE_SANITIZE (this);
1099    if (!u.header.sub_format.sanitize (c))
1100      return TRACE_RETURN (false);
1101    switch (lookup_type) {
1102    case Single:		return TRACE_RETURN (u.single.sanitize (c));
1103    case Multiple:		return TRACE_RETURN (u.multiple.sanitize (c));
1104    case Alternate:		return TRACE_RETURN (u.alternate.sanitize (c));
1105    case Ligature:		return TRACE_RETURN (u.ligature.sanitize (c));
1106    case Context:		return TRACE_RETURN (u.context.sanitize (c));
1107    case ChainContext:		return TRACE_RETURN (u.chainContext.sanitize (c));
1108    case Extension:		return TRACE_RETURN (u.extension.sanitize (c));
1109    case ReverseChainSingle:	return TRACE_RETURN (u.reverseChainContextSingle.sanitize (c));
1110    default:			return TRACE_RETURN (true);
1111    }
1112  }
1113
1114  protected:
1115  union {
1116  struct {
1117    USHORT			sub_format;
1118  } header;
1119  SingleSubst			single;
1120  MultipleSubst			multiple;
1121  AlternateSubst		alternate;
1122  LigatureSubst			ligature;
1123  ContextSubst			context;
1124  ChainContextSubst		chainContext;
1125  ExtensionSubst		extension;
1126  ReverseChainSingleSubst	reverseChainContextSingle;
1127  } u;
1128  public:
1129  DEFINE_SIZE_UNION (2, header.sub_format);
1130};
1131
1132
1133struct SubstLookup : Lookup
1134{
1135  inline const SubstLookupSubTable& get_subtable (unsigned int i) const
1136  { return this+CastR<OffsetArrayOf<SubstLookupSubTable> > (subTable)[i]; }
1137
1138  inline static bool lookup_type_is_reverse (unsigned int lookup_type)
1139  { return lookup_type == SubstLookupSubTable::ReverseChainSingle; }
1140
1141  inline bool is_reverse (void) const
1142  {
1143    unsigned int type = get_type ();
1144    if (unlikely (type == SubstLookupSubTable::Extension))
1145      return CastR<ExtensionSubst> (get_subtable(0)).is_reverse ();
1146    return lookup_type_is_reverse (type);
1147  }
1148
1149  inline hb_closure_context_t::return_t closure (hb_closure_context_t *c) const
1150  {
1151    TRACE_CLOSURE (this);
1152    c->set_recurse_func (dispatch_recurse_func<hb_closure_context_t>);
1153    return TRACE_RETURN (dispatch (c));
1154  }
1155
1156  inline hb_collect_glyphs_context_t::return_t collect_glyphs (hb_collect_glyphs_context_t *c) const
1157  {
1158    TRACE_COLLECT_GLYPHS (this);
1159    c->set_recurse_func (dispatch_recurse_func<hb_collect_glyphs_context_t>);
1160    return TRACE_RETURN (dispatch (c));
1161  }
1162
1163  template <typename set_t>
1164  inline void add_coverage (set_t *glyphs) const
1165  {
1166    hb_get_coverage_context_t c;
1167    const Coverage *last = NULL;
1168    unsigned int count = get_subtable_count ();
1169    for (unsigned int i = 0; i < count; i++) {
1170      const Coverage *coverage = &get_subtable (i).dispatch (&c, get_type ());
1171      if (coverage != last) {
1172        coverage->add_coverage (glyphs);
1173        last = coverage;
1174      }
1175    }
1176  }
1177
1178  inline bool would_apply (hb_would_apply_context_t *c, const hb_set_digest_t *digest) const
1179  {
1180    TRACE_WOULD_APPLY (this);
1181    if (unlikely (!c->len))  return TRACE_RETURN (false);
1182    if (!digest->may_have (c->glyphs[0]))  return TRACE_RETURN (false);
1183      return TRACE_RETURN (dispatch (c));
1184  }
1185
1186  inline bool apply_once (hb_apply_context_t *c) const
1187  {
1188    TRACE_APPLY (this);
1189    if (!c->check_glyph_property (&c->buffer->cur(), c->lookup_props))
1190      return TRACE_RETURN (false);
1191    return TRACE_RETURN (dispatch (c));
1192  }
1193
1194  static bool apply_recurse_func (hb_apply_context_t *c, unsigned int lookup_index);
1195
1196  inline SubstLookupSubTable& serialize_subtable (hb_serialize_context_t *c,
1197						  unsigned int i)
1198  { return CastR<OffsetArrayOf<SubstLookupSubTable> > (subTable)[i].serialize (c, this); }
1199
1200  inline bool serialize_single (hb_serialize_context_t *c,
1201				uint32_t lookup_props,
1202			        Supplier<GlyphID> &glyphs,
1203			        Supplier<GlyphID> &substitutes,
1204			        unsigned int num_glyphs)
1205  {
1206    TRACE_SERIALIZE (this);
1207    if (unlikely (!Lookup::serialize (c, SubstLookupSubTable::Single, lookup_props, 1))) return TRACE_RETURN (false);
1208    return TRACE_RETURN (serialize_subtable (c, 0).u.single.serialize (c, glyphs, substitutes, num_glyphs));
1209  }
1210
1211  inline bool serialize_multiple (hb_serialize_context_t *c,
1212				  uint32_t lookup_props,
1213				  Supplier<GlyphID> &glyphs,
1214				  Supplier<unsigned int> &substitute_len_list,
1215				  unsigned int num_glyphs,
1216				  Supplier<GlyphID> &substitute_glyphs_list)
1217  {
1218    TRACE_SERIALIZE (this);
1219    if (unlikely (!Lookup::serialize (c, SubstLookupSubTable::Multiple, lookup_props, 1))) return TRACE_RETURN (false);
1220    return TRACE_RETURN (serialize_subtable (c, 0).u.multiple.serialize (c, glyphs, substitute_len_list, num_glyphs,
1221									 substitute_glyphs_list));
1222  }
1223
1224  inline bool serialize_alternate (hb_serialize_context_t *c,
1225				   uint32_t lookup_props,
1226				   Supplier<GlyphID> &glyphs,
1227				   Supplier<unsigned int> &alternate_len_list,
1228				   unsigned int num_glyphs,
1229				   Supplier<GlyphID> &alternate_glyphs_list)
1230  {
1231    TRACE_SERIALIZE (this);
1232    if (unlikely (!Lookup::serialize (c, SubstLookupSubTable::Alternate, lookup_props, 1))) return TRACE_RETURN (false);
1233    return TRACE_RETURN (serialize_subtable (c, 0).u.alternate.serialize (c, glyphs, alternate_len_list, num_glyphs,
1234									  alternate_glyphs_list));
1235  }
1236
1237  inline bool serialize_ligature (hb_serialize_context_t *c,
1238				  uint32_t lookup_props,
1239				  Supplier<GlyphID> &first_glyphs,
1240				  Supplier<unsigned int> &ligature_per_first_glyph_count_list,
1241				  unsigned int num_first_glyphs,
1242				  Supplier<GlyphID> &ligatures_list,
1243				  Supplier<unsigned int> &component_count_list,
1244				  Supplier<GlyphID> &component_list /* Starting from second for each ligature */)
1245  {
1246    TRACE_SERIALIZE (this);
1247    if (unlikely (!Lookup::serialize (c, SubstLookupSubTable::Ligature, lookup_props, 1))) return TRACE_RETURN (false);
1248    return TRACE_RETURN (serialize_subtable (c, 0).u.ligature.serialize (c, first_glyphs, ligature_per_first_glyph_count_list, num_first_glyphs,
1249									 ligatures_list, component_count_list, component_list));
1250  }
1251
1252  template <typename context_t>
1253  static inline typename context_t::return_t dispatch_recurse_func (context_t *c, unsigned int lookup_index);
1254
1255  template <typename context_t>
1256  inline typename context_t::return_t dispatch (context_t *c) const
1257  {
1258    TRACE_DISPATCH (this);
1259    unsigned int lookup_type = get_type ();
1260    unsigned int count = get_subtable_count ();
1261    for (unsigned int i = 0; i < count; i++) {
1262      typename context_t::return_t r = get_subtable (i).dispatch (c, lookup_type);
1263      if (c->stop_sublookup_iteration (r))
1264        return TRACE_RETURN (r);
1265    }
1266    return TRACE_RETURN (c->default_return_value ());
1267  }
1268
1269  inline bool sanitize (hb_sanitize_context_t *c)
1270  {
1271    TRACE_SANITIZE (this);
1272    if (unlikely (!Lookup::sanitize (c))) return TRACE_RETURN (false);
1273    OffsetArrayOf<SubstLookupSubTable> &list = CastR<OffsetArrayOf<SubstLookupSubTable> > (subTable);
1274    if (unlikely (!list.sanitize (c, this, get_type ()))) return TRACE_RETURN (false);
1275
1276    if (unlikely (get_type () == SubstLookupSubTable::Extension))
1277    {
1278      /* The spec says all subtables of an Extension lookup should
1279       * have the same type.  This is specially important if one has
1280       * a reverse type! */
1281      unsigned int type = get_subtable (0).u.extension.get_type ();
1282      unsigned int count = get_subtable_count ();
1283      for (unsigned int i = 1; i < count; i++)
1284        if (get_subtable (i).u.extension.get_type () != type)
1285	  return TRACE_RETURN (false);
1286    }
1287    return TRACE_RETURN (true);
1288  }
1289};
1290
1291typedef OffsetListOf<SubstLookup> SubstLookupList;
1292
1293/*
1294 * GSUB -- The Glyph Substitution Table
1295 */
1296
1297struct GSUB : GSUBGPOS
1298{
1299  static const hb_tag_t tableTag	= HB_OT_TAG_GSUB;
1300
1301  inline const SubstLookup& get_lookup (unsigned int i) const
1302  { return CastR<SubstLookup> (GSUBGPOS::get_lookup (i)); }
1303
1304  static inline void substitute_start (hb_font_t *font, hb_buffer_t *buffer);
1305  static inline void substitute_finish (hb_font_t *font, hb_buffer_t *buffer);
1306
1307  inline bool sanitize (hb_sanitize_context_t *c) {
1308    TRACE_SANITIZE (this);
1309    if (unlikely (!GSUBGPOS::sanitize (c))) return TRACE_RETURN (false);
1310    OffsetTo<SubstLookupList> &list = CastR<OffsetTo<SubstLookupList> > (lookupList);
1311    return TRACE_RETURN (list.sanitize (c, this));
1312  }
1313  public:
1314  DEFINE_SIZE_STATIC (10);
1315};
1316
1317
1318void
1319GSUB::substitute_start (hb_font_t *font, hb_buffer_t *buffer)
1320{
1321  _hb_buffer_allocate_gsubgpos_vars (buffer);
1322
1323  const GDEF &gdef = *hb_ot_layout_from_face (font->face)->gdef;
1324  unsigned int count = buffer->len;
1325  for (unsigned int i = 0; i < count; i++)
1326  {
1327    _hb_glyph_info_set_glyph_props (&buffer->info[i], gdef.get_glyph_props (buffer->info[i].codepoint));
1328    _hb_glyph_info_clear_lig_props (&buffer->info[i]);
1329    buffer->info[i].syllable() = 0;
1330  }
1331}
1332
1333void
1334GSUB::substitute_finish (hb_font_t *font HB_UNUSED, hb_buffer_t *buffer HB_UNUSED)
1335{
1336}
1337
1338
1339/* Out-of-class implementation for methods recursing */
1340
1341inline bool ExtensionSubst::is_reverse (void) const
1342{
1343  unsigned int type = get_type ();
1344  if (unlikely (type == SubstLookupSubTable::Extension))
1345    return CastR<ExtensionSubst> (get_subtable<SubstLookupSubTable>()).is_reverse ();
1346  return SubstLookup::lookup_type_is_reverse (type);
1347}
1348
1349template <typename context_t>
1350inline typename context_t::return_t SubstLookup::dispatch_recurse_func (context_t *c, unsigned int lookup_index)
1351{
1352  const GSUB &gsub = *(hb_ot_layout_from_face (c->face)->gsub);
1353  const SubstLookup &l = gsub.get_lookup (lookup_index);
1354  return l.dispatch (c);
1355}
1356
1357inline bool SubstLookup::apply_recurse_func (hb_apply_context_t *c, unsigned int lookup_index)
1358{
1359  const GSUB &gsub = *(hb_ot_layout_from_face (c->face)->gsub);
1360  const SubstLookup &l = gsub.get_lookup (lookup_index);
1361  unsigned int saved_lookup_props = c->lookup_props;
1362  c->set_lookup (l);
1363  bool ret = l.apply_once (c);
1364  c->lookup_props = saved_lookup_props;
1365  return ret;
1366}
1367
1368
1369} /* namespace OT */
1370
1371
1372#endif /* HB_OT_LAYOUT_GSUB_TABLE_HH */
1373