hb-ot-layout-common-private.hh revision 5bd1e95236320aed60fb29ca1e93b9595d4aeeec 
1/*
2 * Copyright (C) 2007,2008,2009  Red Hat, Inc.
3 * Copyright (C) 2010  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_COMMON_PRIVATE_HH
30#define HB_OT_LAYOUT_COMMON_PRIVATE_HH
31
32#include "hb-ot-layout-private.hh"
33
34#include "hb-open-type-private.hh"
35
36
37#define NO_CONTEXT		((unsigned int) 0x110000)
38#define NOT_COVERED		((unsigned int) 0x110000)
39#define MAX_NESTING_LEVEL	8
40
41HB_BEGIN_DECLS
42HB_END_DECLS
43
44
45/*
46 *
47 * OpenType Layout Common Table Formats
48 *
49 */
50
51
52/*
53 * Script, ScriptList, LangSys, Feature, FeatureList, Lookup, LookupList
54 */
55
56template <typename Type>
57struct Record
58{
59  inline int cmp (hb_tag_t b) const {
60    hb_tag_t a = tag;
61    return b < a ? -1 : b == a ? 0 : -1;
62  }
63
64  inline bool sanitize (hb_sanitize_context_t *c, void *base) {
65    TRACE_SANITIZE ();
66    return c->check_struct (this)
67	&& offset.sanitize (c, base);
68  }
69
70  Tag		tag;		/* 4-byte Tag identifier */
71  OffsetTo<Type>
72		offset;		/* Offset from beginning of object holding
73				 * the Record */
74  public:
75  DEFINE_SIZE_STATIC (6);
76};
77
78template <typename Type>
79struct RecordArrayOf : SortedArrayOf<Record<Type> > {
80  inline const Tag& get_tag (unsigned int i) const
81  {
82    if (unlikely (i >= this->len)) return Null(Tag);
83    return (*this)[i].tag;
84  }
85  inline unsigned int get_tags (unsigned int start_offset,
86				unsigned int *record_count /* IN/OUT */,
87				hb_tag_t     *record_tags /* OUT */) const
88  {
89    if (record_count) {
90      const Record<Type> *array = this->sub_array (start_offset, record_count);
91      unsigned int count = *record_count;
92      for (unsigned int i = 0; i < count; i++)
93	record_tags[i] = array[i].tag;
94    }
95    return this->len;
96  }
97  inline bool find_index (hb_tag_t tag, unsigned int *index) const
98  {
99    int i = this->search (tag);
100    if (i != -1) {
101        if (index) *index = i;
102        return true;
103    } else {
104      if (index) *index = Index::NOT_FOUND_INDEX;
105      return false;
106    }
107  }
108};
109
110template <typename Type>
111struct RecordListOf : RecordArrayOf<Type>
112{
113  inline const Type& operator [] (unsigned int i) const
114  { return this+RecordArrayOf<Type>::operator [](i).offset; }
115
116  inline bool sanitize (hb_sanitize_context_t *c) {
117    TRACE_SANITIZE ();
118    return RecordArrayOf<Type>::sanitize (c, this);
119  }
120};
121
122
123struct RangeRecord
124{
125  inline int cmp (hb_codepoint_t g) const {
126    hb_codepoint_t a = start, b = end;
127    return g < a ? -1 : g <= b ? 0 : +1 ;
128  }
129
130  inline bool sanitize (hb_sanitize_context_t *c) {
131    TRACE_SANITIZE ();
132    return c->check_struct (this);
133  }
134
135  GlyphID	start;		/* First GlyphID in the range */
136  GlyphID	end;		/* Last GlyphID in the range */
137  USHORT	value;		/* Value */
138  public:
139  DEFINE_SIZE_STATIC (6);
140};
141DEFINE_NULL_DATA (RangeRecord, "\000\001");
142
143
144struct IndexArray : ArrayOf<Index>
145{
146  inline unsigned int get_indexes (unsigned int start_offset,
147				   unsigned int *_count /* IN/OUT */,
148				   unsigned int *_indexes /* OUT */) const
149  {
150    if (_count) {
151      const USHORT *array = this->sub_array (start_offset, _count);
152      unsigned int count = *_count;
153      for (unsigned int i = 0; i < count; i++)
154	_indexes[i] = array[i];
155    }
156    return this->len;
157  }
158};
159
160
161struct Script;
162struct LangSys;
163struct Feature;
164
165
166struct LangSys
167{
168  inline unsigned int get_feature_count (void) const
169  { return featureIndex.len; }
170  inline hb_tag_t get_feature_index (unsigned int i) const
171  { return featureIndex[i]; }
172  inline unsigned int get_feature_indexes (unsigned int start_offset,
173					   unsigned int *feature_count /* IN/OUT */,
174					   unsigned int *feature_indexes /* OUT */) const
175  { return featureIndex.get_indexes (start_offset, feature_count, feature_indexes); }
176
177  inline bool has_required_feature (void) const { return reqFeatureIndex != 0xffff; }
178  inline unsigned int get_required_feature_index (void) const
179  {
180    if (reqFeatureIndex == 0xffff)
181      return Index::NOT_FOUND_INDEX;
182   return reqFeatureIndex;;
183  }
184
185  inline bool sanitize (hb_sanitize_context_t *c) {
186    TRACE_SANITIZE ();
187    return c->check_struct (this)
188	&& featureIndex.sanitize (c);
189  }
190
191  Offset	lookupOrder;	/* = Null (reserved for an offset to a
192				 * reordering table) */
193  USHORT	reqFeatureIndex;/* Index of a feature required for this
194				 * language system--if no required features
195				 * = 0xFFFF */
196  IndexArray	featureIndex;	/* Array of indices into the FeatureList */
197  public:
198  DEFINE_SIZE_ARRAY (6, featureIndex);
199};
200DEFINE_NULL_DATA (LangSys, "\0\0\xFF\xFF");
201
202
203struct Script
204{
205  inline unsigned int get_lang_sys_count (void) const
206  { return langSys.len; }
207  inline const Tag& get_lang_sys_tag (unsigned int i) const
208  { return langSys.get_tag (i); }
209  inline unsigned int get_lang_sys_tags (unsigned int start_offset,
210					 unsigned int *lang_sys_count /* IN/OUT */,
211					 hb_tag_t     *lang_sys_tags /* OUT */) const
212  { return langSys.get_tags (start_offset, lang_sys_count, lang_sys_tags); }
213  inline const LangSys& get_lang_sys (unsigned int i) const
214  {
215    if (i == Index::NOT_FOUND_INDEX) return get_default_lang_sys ();
216    return this+langSys[i].offset;
217  }
218  inline bool find_lang_sys_index (hb_tag_t tag, unsigned int *index) const
219  { return langSys.find_index (tag, index); }
220
221  inline bool has_default_lang_sys (void) const { return defaultLangSys != 0; }
222  inline const LangSys& get_default_lang_sys (void) const { return this+defaultLangSys; }
223
224  inline bool sanitize (hb_sanitize_context_t *c) {
225    TRACE_SANITIZE ();
226    return defaultLangSys.sanitize (c, this)
227	&& langSys.sanitize (c, this);
228  }
229
230  private:
231  OffsetTo<LangSys>
232		defaultLangSys;	/* Offset to DefaultLangSys table--from
233				 * beginning of Script table--may be Null */
234  RecordArrayOf<LangSys>
235		langSys;	/* Array of LangSysRecords--listed
236				 * alphabetically by LangSysTag */
237  public:
238  DEFINE_SIZE_ARRAY (4, langSys);
239};
240
241typedef RecordListOf<Script> ScriptList;
242
243
244struct Feature
245{
246  inline unsigned int get_lookup_count (void) const
247  { return lookupIndex.len; }
248  inline hb_tag_t get_lookup_index (unsigned int i) const
249  { return lookupIndex[i]; }
250  inline unsigned int get_lookup_indexes (unsigned int start_index,
251					  unsigned int *lookup_count /* IN/OUT */,
252					  unsigned int *lookup_tags /* OUT */) const
253  { return lookupIndex.get_indexes (start_index, lookup_count, lookup_tags); }
254
255  inline bool sanitize (hb_sanitize_context_t *c) {
256    TRACE_SANITIZE ();
257    return c->check_struct (this)
258	&& lookupIndex.sanitize (c);
259  }
260
261  /* LONGTERMTODO: implement get_feature_parameters() */
262  /* LONGTERMTODO: implement FeatureSize and other special features? */
263  Offset	featureParams;	/* Offset to Feature Parameters table (if one
264				 * has been defined for the feature), relative
265				 * to the beginning of the Feature Table; = Null
266				 * if not required */
267  IndexArray	 lookupIndex;	/* Array of LookupList indices */
268  public:
269  DEFINE_SIZE_ARRAY (4, lookupIndex);
270};
271
272typedef RecordListOf<Feature> FeatureList;
273
274
275struct LookupFlag : USHORT
276{
277  enum {
278    RightToLeft		= 0x0001u,
279    IgnoreBaseGlyphs	= 0x0002u,
280    IgnoreLigatures	= 0x0004u,
281    IgnoreMarks		= 0x0008u,
282    IgnoreFlags		= 0x000Eu,
283    UseMarkFilteringSet	= 0x0010u,
284    Reserved		= 0x00E0u,
285    MarkAttachmentType	= 0xFF00u
286  };
287  public:
288  DEFINE_SIZE_STATIC (2);
289};
290
291struct Lookup
292{
293  inline unsigned int get_subtable_count (void) const { return subTable.len; }
294
295  inline unsigned int get_type (void) const { return lookupType; }
296  inline unsigned int get_flag (void) const
297  {
298    unsigned int flag = lookupFlag;
299    if (unlikely (flag & LookupFlag::UseMarkFilteringSet))
300    {
301      const USHORT &markFilteringSet = StructAfter<USHORT> (subTable);
302      flag += (markFilteringSet << 16);
303    }
304    return flag;
305  }
306
307  inline bool sanitize (hb_sanitize_context_t *c) {
308    TRACE_SANITIZE ();
309    /* Real sanitize of the subtables is done by GSUB/GPOS/... */
310    if (!(c->check_struct (this)
311       && subTable.sanitize (c))) return false;
312    if (unlikely (lookupFlag & LookupFlag::UseMarkFilteringSet))
313    {
314      USHORT &markFilteringSet = StructAfter<USHORT> (subTable);
315      if (!markFilteringSet.sanitize (c)) return false;
316    }
317    return true;
318  }
319
320  USHORT	lookupType;		/* Different enumerations for GSUB and GPOS */
321  USHORT	lookupFlag;		/* Lookup qualifiers */
322  ArrayOf<Offset>
323		subTable;		/* Array of SubTables */
324  USHORT	markFilteringSetX[VAR];	/* Index (base 0) into GDEF mark glyph sets
325					 * structure. This field is only present if bit
326					 * UseMarkFilteringSet of lookup flags is set. */
327  public:
328  DEFINE_SIZE_ARRAY2 (6, subTable, markFilteringSetX);
329};
330
331typedef OffsetListOf<Lookup> LookupList;
332
333
334/*
335 * Coverage Table
336 */
337
338struct CoverageFormat1
339{
340  friend struct Coverage;
341
342  private:
343  inline unsigned int get_coverage (hb_codepoint_t glyph_id) const
344  {
345    int i = glyphArray.search (glyph_id);
346    if (i != -1)
347        return i;
348    return NOT_COVERED;
349  }
350
351  inline bool sanitize (hb_sanitize_context_t *c) {
352    TRACE_SANITIZE ();
353    return glyphArray.sanitize (c);
354  }
355
356  private:
357  USHORT	coverageFormat;	/* Format identifier--format = 1 */
358  SortedArrayOf<GlyphID>
359		glyphArray;	/* Array of GlyphIDs--in numerical order */
360  public:
361  DEFINE_SIZE_ARRAY (4, glyphArray);
362};
363
364struct CoverageFormat2
365{
366  friend struct Coverage;
367
368  private:
369  inline unsigned int get_coverage (hb_codepoint_t glyph_id) const
370  {
371    int i = rangeRecord.search (glyph_id);
372    if (i != -1) {
373      const RangeRecord &range = rangeRecord[i];
374      return (unsigned int) range.value + (glyph_id - range.start);
375    }
376    return NOT_COVERED;
377  }
378
379  inline bool sanitize (hb_sanitize_context_t *c) {
380    TRACE_SANITIZE ();
381    return rangeRecord.sanitize (c);
382  }
383
384  private:
385  USHORT	coverageFormat;	/* Format identifier--format = 2 */
386  SortedArrayOf<RangeRecord>
387		rangeRecord;	/* Array of glyph ranges--ordered by
388				 * Start GlyphID. rangeCount entries
389				 * long */
390  public:
391  DEFINE_SIZE_ARRAY (4, rangeRecord);
392};
393
394struct Coverage
395{
396  inline unsigned int operator () (hb_codepoint_t glyph_id) const { return get_coverage (glyph_id); }
397
398  inline unsigned int get_coverage (hb_codepoint_t glyph_id) const
399  {
400    switch (u.format) {
401    case 1: return u.format1.get_coverage(glyph_id);
402    case 2: return u.format2.get_coverage(glyph_id);
403    default:return NOT_COVERED;
404    }
405  }
406
407  inline bool sanitize (hb_sanitize_context_t *c) {
408    TRACE_SANITIZE ();
409    if (!u.format.sanitize (c)) return false;
410    switch (u.format) {
411    case 1: return u.format1.sanitize (c);
412    case 2: return u.format2.sanitize (c);
413    default:return true;
414    }
415  }
416
417  private:
418  union {
419  USHORT		format;		/* Format identifier */
420  CoverageFormat1	format1;
421  CoverageFormat2	format2;
422  } u;
423  public:
424  DEFINE_SIZE_UNION (2, format);
425};
426
427
428/*
429 * Class Definition Table
430 */
431
432struct ClassDefFormat1
433{
434  friend struct ClassDef;
435
436  private:
437  inline hb_ot_layout_class_t get_class (hb_codepoint_t glyph_id) const
438  {
439    if ((unsigned int) (glyph_id - startGlyph) < classValue.len)
440      return classValue[glyph_id - startGlyph];
441    return 0;
442  }
443
444  inline bool sanitize (hb_sanitize_context_t *c) {
445    TRACE_SANITIZE ();
446    return c->check_struct (this)
447	&& classValue.sanitize (c);
448  }
449
450  USHORT	classFormat;		/* Format identifier--format = 1 */
451  GlyphID	startGlyph;		/* First GlyphID of the classValueArray */
452  ArrayOf<USHORT>
453		classValue;		/* Array of Class Values--one per GlyphID */
454  public:
455  DEFINE_SIZE_ARRAY (6, classValue);
456};
457
458struct ClassDefFormat2
459{
460  friend struct ClassDef;
461
462  private:
463  inline hb_ot_layout_class_t get_class (hb_codepoint_t glyph_id) const
464  {
465    int i = rangeRecord.search (glyph_id);
466    if (i != -1)
467      return rangeRecord[i].value;
468    return 0;
469  }
470
471  inline bool sanitize (hb_sanitize_context_t *c) {
472    TRACE_SANITIZE ();
473    return rangeRecord.sanitize (c);
474  }
475
476  USHORT	classFormat;	/* Format identifier--format = 2 */
477  SortedArrayOf<RangeRecord>
478		rangeRecord;	/* Array of glyph ranges--ordered by
479				 * Start GlyphID */
480  public:
481  DEFINE_SIZE_ARRAY (4, rangeRecord);
482};
483
484struct ClassDef
485{
486  inline hb_ot_layout_class_t operator () (hb_codepoint_t glyph_id) const { return get_class (glyph_id); }
487
488  inline hb_ot_layout_class_t get_class (hb_codepoint_t glyph_id) const
489  {
490    switch (u.format) {
491    case 1: return u.format1.get_class(glyph_id);
492    case 2: return u.format2.get_class(glyph_id);
493    default:return 0;
494    }
495  }
496
497  inline bool sanitize (hb_sanitize_context_t *c) {
498    TRACE_SANITIZE ();
499    if (!u.format.sanitize (c)) return false;
500    switch (u.format) {
501    case 1: return u.format1.sanitize (c);
502    case 2: return u.format2.sanitize (c);
503    default:return true;
504    }
505  }
506
507  private:
508  union {
509  USHORT		format;		/* Format identifier */
510  ClassDefFormat1	format1;
511  ClassDefFormat2	format2;
512  } u;
513  public:
514  DEFINE_SIZE_UNION (2, format);
515};
516
517
518/*
519 * Device Tables
520 */
521
522struct Device
523{
524
525  inline hb_position_t get_x_delta (hb_ot_layout_context_t *c) const
526  { return get_delta (c->font->x_ppem, c->font->x_scale); }
527
528  inline hb_position_t get_y_delta (hb_ot_layout_context_t *c) const
529  { return get_delta (c->font->y_ppem, c->font->y_scale); }
530
531  inline int get_delta (unsigned int ppem, unsigned int scale) const
532  {
533    if (!ppem) return 0;
534
535    int pixels = get_delta_pixels (ppem);
536
537    if (!pixels) return 0;
538
539    /* pixels is at most in the -8..7 range.  So 64-bit arithmetic is
540     * not really necessary here.  A simple cast to int may just work
541     * as well.  But since this code is not reached that often and
542     * for the sake of correctness, we do a 64bit operation. */
543    return pixels * (int64_t) scale / ppem;
544  }
545
546
547  inline int get_delta_pixels (unsigned int ppem_size) const
548  {
549    unsigned int f = deltaFormat;
550    if (unlikely (f < 1 || f > 3))
551      return 0;
552
553    if (ppem_size < startSize || ppem_size > endSize)
554      return 0;
555
556    unsigned int s = ppem_size - startSize;
557
558    unsigned int byte = deltaValue[s >> (4 - f)];
559    unsigned int bits = (byte >> (16 - (((s & ((1 << (4 - f)) - 1)) + 1) << f)));
560    unsigned int mask = (0xFFFF >> (16 - (1 << f)));
561
562    int delta = bits & mask;
563
564    if ((unsigned int) delta >= ((mask + 1) >> 1))
565      delta -= mask + 1;
566
567    return delta;
568  }
569
570  inline unsigned int get_size () const
571  {
572    unsigned int f = deltaFormat;
573    if (unlikely (f < 1 || f > 3 || startSize > endSize)) return 3 * USHORT::static_size;
574    return USHORT::static_size * (4 + ((endSize - startSize) >> (4 - f)));
575  }
576
577  inline bool sanitize (hb_sanitize_context_t *c) {
578    TRACE_SANITIZE ();
579    return c->check_struct (this)
580	&& c->check_range (this, this->get_size ());
581  }
582
583  private:
584  USHORT	startSize;		/* Smallest size to correct--in ppem */
585  USHORT	endSize;		/* Largest size to correct--in ppem */
586  USHORT	deltaFormat;		/* Format of DeltaValue array data: 1, 2, or 3
587					 * 1	Signed 2-bit value, 8 values per uint16
588					 * 2	Signed 4-bit value, 4 values per uint16
589					 * 3	Signed 8-bit value, 2 values per uint16
590					 */
591  USHORT	deltaValue[VAR];	/* Array of compressed data */
592  public:
593  DEFINE_SIZE_ARRAY (6, deltaValue);
594};
595
596
597HB_BEGIN_DECLS
598HB_END_DECLS
599
600#endif /* HB_OT_LAYOUT_COMMON_PRIVATE_HH */
601