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_GPOS_TABLE_HH
30 #define HB_OT_LAYOUT_GPOS_TABLE_HH
31 
32 #include "hb-ot-layout-gsubgpos.hh"
33 
34 
35 namespace OT {
36 
37 
38 /* buffer **position** var allocations */
39 #define attach_chain() var.i16[0] /* glyph to which this attaches to, relative to current glyphs; negative for going back, positive for forward. */
40 #define attach_type() var.u8[2] /* attachment type */
41 /* Note! if attach_chain() is zero, the value of attach_type() is irrelevant. */
42 
43 enum attach_type_t {
44   ATTACH_TYPE_NONE	= 0X00,
45 
46   /* Each attachment should be either a mark or a cursive; can't be both. */
47   ATTACH_TYPE_MARK	= 0X01,
48   ATTACH_TYPE_CURSIVE	= 0X02,
49 };
50 
51 
52 /* Shared Tables: ValueRecord, Anchor Table, and MarkArray */
53 
54 typedef HBUINT16 Value;
55 
56 typedef UnsizedArrayOf<Value> ValueRecord;
57 
58 struct ValueFormat : HBUINT16
59 {
60   enum Flags {
61     xPlacement	= 0x0001u,	/* Includes horizontal adjustment for placement */
62     yPlacement	= 0x0002u,	/* Includes vertical adjustment for placement */
63     xAdvance	= 0x0004u,	/* Includes horizontal adjustment for advance */
64     yAdvance	= 0x0008u,	/* Includes vertical adjustment for advance */
65     xPlaDevice	= 0x0010u,	/* Includes horizontal Device table for placement */
66     yPlaDevice	= 0x0020u,	/* Includes vertical Device table for placement */
67     xAdvDevice	= 0x0040u,	/* Includes horizontal Device table for advance */
68     yAdvDevice	= 0x0080u,	/* Includes vertical Device table for advance */
69     ignored	= 0x0F00u,	/* Was used in TrueType Open for MM fonts */
70     reserved	= 0xF000u,	/* For future use */
71 
72     devices	= 0x00F0u	/* Mask for having any Device table */
73   };
74 
75 /* All fields are options.  Only those available advance the value pointer. */
76 #if 0
77   HBINT16		xPlacement;		/* Horizontal adjustment for
78 					 * placement--in design units */
79   HBINT16		yPlacement;		/* Vertical adjustment for
80 					 * placement--in design units */
81   HBINT16		xAdvance;		/* Horizontal adjustment for
82 					 * advance--in design units (only used
83 					 * for horizontal writing) */
84   HBINT16		yAdvance;		/* Vertical adjustment for advance--in
85 					 * design units (only used for vertical
86 					 * writing) */
87   OffsetTo<Device>	xPlaDevice;	/* Offset to Device table for
88 					 * horizontal placement--measured from
89 					 * beginning of PosTable (may be NULL) */
90   OffsetTo<Device>	yPlaDevice;	/* Offset to Device table for vertical
91 					 * placement--measured from beginning
92 					 * of PosTable (may be NULL) */
93   OffsetTo<Device>	xAdvDevice;	/* Offset to Device table for
94 					 * horizontal advance--measured from
95 					 * beginning of PosTable (may be NULL) */
96   OffsetTo<Device>	yAdvDevice;	/* Offset to Device table for vertical
97 					 * advance--measured from beginning of
98 					 * PosTable (may be NULL) */
99 #endif
100 
get_lenOT::ValueFormat101   unsigned int get_len () const  { return hb_popcount ((unsigned int) *this); }
get_sizeOT::ValueFormat102   unsigned int get_size () const { return get_len () * Value::static_size; }
103 
apply_valueOT::ValueFormat104   bool apply_value (hb_ot_apply_context_t *c,
105 		    const void            *base,
106 		    const Value           *values,
107 		    hb_glyph_position_t   &glyph_pos) const
108   {
109     bool ret = false;
110     unsigned int format = *this;
111     if (!format) return ret;
112 
113     hb_font_t *font = c->font;
114     bool horizontal = HB_DIRECTION_IS_HORIZONTAL (c->direction);
115 
116     if (format & xPlacement) glyph_pos.x_offset  += font->em_scale_x (get_short (values++, &ret));
117     if (format & yPlacement) glyph_pos.y_offset  += font->em_scale_y (get_short (values++, &ret));
118     if (format & xAdvance) {
119       if (likely (horizontal)) glyph_pos.x_advance += font->em_scale_x (get_short (values, &ret));
120       values++;
121     }
122     /* y_advance values grow downward but font-space grows upward, hence negation */
123     if (format & yAdvance) {
124       if (unlikely (!horizontal)) glyph_pos.y_advance -= font->em_scale_y (get_short (values, &ret));
125       values++;
126     }
127 
128     if (!has_device ()) return ret;
129 
130     bool use_x_device = font->x_ppem || font->num_coords;
131     bool use_y_device = font->y_ppem || font->num_coords;
132 
133     if (!use_x_device && !use_y_device) return ret;
134 
135     const VariationStore &store = c->var_store;
136 
137     /* pixel -> fractional pixel */
138     if (format & xPlaDevice) {
139       if (use_x_device) glyph_pos.x_offset  += (base + get_device (values, &ret)).get_x_delta (font, store);
140       values++;
141     }
142     if (format & yPlaDevice) {
143       if (use_y_device) glyph_pos.y_offset  += (base + get_device (values, &ret)).get_y_delta (font, store);
144       values++;
145     }
146     if (format & xAdvDevice) {
147       if (horizontal && use_x_device) glyph_pos.x_advance += (base + get_device (values, &ret)).get_x_delta (font, store);
148       values++;
149     }
150     if (format & yAdvDevice) {
151       /* y_advance values grow downward but font-space grows upward, hence negation */
152       if (!horizontal && use_y_device) glyph_pos.y_advance -= (base + get_device (values, &ret)).get_y_delta (font, store);
153       values++;
154     }
155     return ret;
156   }
157 
158   private:
sanitize_value_devicesOT::ValueFormat159   bool sanitize_value_devices (hb_sanitize_context_t *c, const void *base, const Value *values) const
160   {
161     unsigned int format = *this;
162 
163     if (format & xPlacement) values++;
164     if (format & yPlacement) values++;
165     if (format & xAdvance)   values++;
166     if (format & yAdvance)   values++;
167 
168     if ((format & xPlaDevice) && !get_device (values++).sanitize (c, base)) return false;
169     if ((format & yPlaDevice) && !get_device (values++).sanitize (c, base)) return false;
170     if ((format & xAdvDevice) && !get_device (values++).sanitize (c, base)) return false;
171     if ((format & yAdvDevice) && !get_device (values++).sanitize (c, base)) return false;
172 
173     return true;
174   }
175 
get_deviceOT::ValueFormat176   HB_INTERNAL static OffsetTo<Device>& get_device (Value* value)
177   { return *CastP<OffsetTo<Device>> (value); }
get_deviceOT::ValueFormat178   HB_INTERNAL static const OffsetTo<Device>& get_device (const Value* value, bool *worked=nullptr)
179   {
180     if (worked) *worked |= bool (*value);
181     return *CastP<OffsetTo<Device>> (value);
182   }
183 
get_shortOT::ValueFormat184   HB_INTERNAL static const HBINT16& get_short (const Value* value, bool *worked=nullptr)
185   {
186     if (worked) *worked |= bool (*value);
187     return *CastP<HBINT16> (value);
188   }
189 
190   public:
191 
has_deviceOT::ValueFormat192   bool has_device () const
193   {
194     unsigned int format = *this;
195     return (format & devices) != 0;
196   }
197 
sanitize_valueOT::ValueFormat198   bool sanitize_value (hb_sanitize_context_t *c, const void *base, const Value *values) const
199   {
200     TRACE_SANITIZE (this);
201     return_trace (c->check_range (values, get_size ()) && (!has_device () || sanitize_value_devices (c, base, values)));
202   }
203 
sanitize_valuesOT::ValueFormat204   bool sanitize_values (hb_sanitize_context_t *c, const void *base, const Value *values, unsigned int count) const
205   {
206     TRACE_SANITIZE (this);
207     unsigned int len = get_len ();
208 
209     if (!c->check_range (values, count, get_size ())) return_trace (false);
210 
211     if (!has_device ()) return_trace (true);
212 
213     for (unsigned int i = 0; i < count; i++) {
214       if (!sanitize_value_devices (c, base, values))
215 	return_trace (false);
216       values += len;
217     }
218 
219     return_trace (true);
220   }
221 
222   /* Just sanitize referenced Device tables.  Doesn't check the values themselves. */
sanitize_values_stride_unsafeOT::ValueFormat223   bool sanitize_values_stride_unsafe (hb_sanitize_context_t *c, const void *base, const Value *values, unsigned int count, unsigned int stride) const
224   {
225     TRACE_SANITIZE (this);
226 
227     if (!has_device ()) return_trace (true);
228 
229     for (unsigned int i = 0; i < count; i++) {
230       if (!sanitize_value_devices (c, base, values))
231 	return_trace (false);
232       values += stride;
233     }
234 
235     return_trace (true);
236   }
237 };
238 
239 template<typename Iterator>
240 static inline void SinglePos_serialize (hb_serialize_context_t *c,
241 					Iterator it,
242 					ValueFormat valFormat);
243 
244 
245 struct AnchorFormat1
246 {
get_anchorOT::AnchorFormat1247   void get_anchor (hb_ot_apply_context_t *c, hb_codepoint_t glyph_id HB_UNUSED,
248 		   float *x, float *y) const
249   {
250     hb_font_t *font = c->font;
251     *x = font->em_fscale_x (xCoordinate);
252     *y = font->em_fscale_y (yCoordinate);
253   }
254 
sanitizeOT::AnchorFormat1255   bool sanitize (hb_sanitize_context_t *c) const
256   {
257     TRACE_SANITIZE (this);
258     return_trace (c->check_struct (this));
259   }
260 
copyOT::AnchorFormat1261   AnchorFormat1* copy (hb_serialize_context_t *c) const
262   {
263     TRACE_SERIALIZE (this);
264     return_trace (c->embed<AnchorFormat1> (this));
265   }
266 
267   protected:
268   HBUINT16	format;			/* Format identifier--format = 1 */
269   FWORD		xCoordinate;		/* Horizontal value--in design units */
270   FWORD		yCoordinate;		/* Vertical value--in design units */
271   public:
272   DEFINE_SIZE_STATIC (6);
273 };
274 
275 struct AnchorFormat2
276 {
get_anchorOT::AnchorFormat2277   void get_anchor (hb_ot_apply_context_t *c, hb_codepoint_t glyph_id,
278 		   float *x, float *y) const
279   {
280     hb_font_t *font = c->font;
281 
282 #ifdef HB_NO_HINTING
283     *x = font->em_fscale_x (xCoordinate);
284     *y = font->em_fscale_y (yCoordinate);
285     return;
286 #endif
287 
288     unsigned int x_ppem = font->x_ppem;
289     unsigned int y_ppem = font->y_ppem;
290     hb_position_t cx = 0, cy = 0;
291     bool ret;
292 
293     ret = (x_ppem || y_ppem) &&
294 	  font->get_glyph_contour_point_for_origin (glyph_id, anchorPoint, HB_DIRECTION_LTR, &cx, &cy);
295     *x = ret && x_ppem ? cx : font->em_fscale_x (xCoordinate);
296     *y = ret && y_ppem ? cy : font->em_fscale_y (yCoordinate);
297   }
298 
sanitizeOT::AnchorFormat2299   bool sanitize (hb_sanitize_context_t *c) const
300   {
301     TRACE_SANITIZE (this);
302     return_trace (c->check_struct (this));
303   }
304 
copyOT::AnchorFormat2305   AnchorFormat2* copy (hb_serialize_context_t *c) const
306   {
307     TRACE_SERIALIZE (this);
308     return_trace (c->embed<AnchorFormat2> (this));
309   }
310 
311   protected:
312   HBUINT16	format;			/* Format identifier--format = 2 */
313   FWORD		xCoordinate;		/* Horizontal value--in design units */
314   FWORD		yCoordinate;		/* Vertical value--in design units */
315   HBUINT16	anchorPoint;		/* Index to glyph contour point */
316   public:
317   DEFINE_SIZE_STATIC (8);
318 };
319 
320 struct AnchorFormat3
321 {
get_anchorOT::AnchorFormat3322   void get_anchor (hb_ot_apply_context_t *c, hb_codepoint_t glyph_id HB_UNUSED,
323 		   float *x, float *y) const
324   {
325     hb_font_t *font = c->font;
326     *x = font->em_fscale_x (xCoordinate);
327     *y = font->em_fscale_y (yCoordinate);
328 
329     if (font->x_ppem || font->num_coords)
330       *x += (this+xDeviceTable).get_x_delta (font, c->var_store);
331     if (font->y_ppem || font->num_coords)
332       *y += (this+yDeviceTable).get_y_delta (font, c->var_store);
333   }
334 
sanitizeOT::AnchorFormat3335   bool sanitize (hb_sanitize_context_t *c) const
336   {
337     TRACE_SANITIZE (this);
338     return_trace (c->check_struct (this) && xDeviceTable.sanitize (c, this) && yDeviceTable.sanitize (c, this));
339   }
340 
copyOT::AnchorFormat3341   AnchorFormat3* copy (hb_serialize_context_t *c) const
342   {
343     TRACE_SERIALIZE (this);
344     auto *out = c->embed<AnchorFormat3> (this);
345     if (unlikely (!out)) return_trace (nullptr);
346 
347     out->xDeviceTable.serialize_copy (c, xDeviceTable, this, out);
348     out->yDeviceTable.serialize_copy (c, yDeviceTable, this, out);
349     return_trace (out);
350   }
351 
352   protected:
353   HBUINT16	format;			/* Format identifier--format = 3 */
354   FWORD		xCoordinate;		/* Horizontal value--in design units */
355   FWORD		yCoordinate;		/* Vertical value--in design units */
356   OffsetTo<Device>
357 		xDeviceTable;		/* Offset to Device table for X
358 					 * coordinate-- from beginning of
359 					 * Anchor table (may be NULL) */
360   OffsetTo<Device>
361 		yDeviceTable;		/* Offset to Device table for Y
362 					 * coordinate-- from beginning of
363 					 * Anchor table (may be NULL) */
364   public:
365   DEFINE_SIZE_STATIC (10);
366 };
367 
368 struct Anchor
369 {
get_anchorOT::Anchor370   void get_anchor (hb_ot_apply_context_t *c, hb_codepoint_t glyph_id,
371 		   float *x, float *y) const
372   {
373     *x = *y = 0;
374     switch (u.format) {
375     case 1: u.format1.get_anchor (c, glyph_id, x, y); return;
376     case 2: u.format2.get_anchor (c, glyph_id, x, y); return;
377     case 3: u.format3.get_anchor (c, glyph_id, x, y); return;
378     default:					      return;
379     }
380   }
381 
sanitizeOT::Anchor382   bool sanitize (hb_sanitize_context_t *c) const
383   {
384     TRACE_SANITIZE (this);
385     if (!u.format.sanitize (c)) return_trace (false);
386     switch (u.format) {
387     case 1: return_trace (u.format1.sanitize (c));
388     case 2: return_trace (u.format2.sanitize (c));
389     case 3: return_trace (u.format3.sanitize (c));
390     default:return_trace (true);
391     }
392   }
393 
copyOT::Anchor394   Anchor* copy (hb_serialize_context_t *c) const
395   {
396     TRACE_SERIALIZE (this);
397     switch (u.format) {
398     case 1: return_trace (reinterpret_cast<Anchor *> (u.format1.copy (c)));
399     case 2: return_trace (reinterpret_cast<Anchor *> (u.format2.copy (c)));
400     case 3: return_trace (reinterpret_cast<Anchor *> (u.format3.copy (c)));
401     default:return_trace (nullptr);
402     }
403   }
404 
405   protected:
406   union {
407   HBUINT16		format;		/* Format identifier */
408   AnchorFormat1		format1;
409   AnchorFormat2		format2;
410   AnchorFormat3		format3;
411   } u;
412   public:
413   DEFINE_SIZE_UNION (2, format);
414 };
415 
416 
417 struct AnchorMatrix
418 {
get_anchorOT::AnchorMatrix419   const Anchor& get_anchor (unsigned int row, unsigned int col,
420 			    unsigned int cols, bool *found) const
421   {
422     *found = false;
423     if (unlikely (row >= rows || col >= cols)) return Null(Anchor);
424     *found = !matrixZ[row * cols + col].is_null ();
425     return this+matrixZ[row * cols + col];
426   }
427 
sanitizeOT::AnchorMatrix428   bool sanitize (hb_sanitize_context_t *c, unsigned int cols) const
429   {
430     TRACE_SANITIZE (this);
431     if (!c->check_struct (this)) return_trace (false);
432     if (unlikely (hb_unsigned_mul_overflows (rows, cols))) return_trace (false);
433     unsigned int count = rows * cols;
434     if (!c->check_array (matrixZ.arrayZ, count)) return_trace (false);
435     for (unsigned int i = 0; i < count; i++)
436       if (!matrixZ[i].sanitize (c, this)) return_trace (false);
437     return_trace (true);
438   }
439 
440   HBUINT16	rows;			/* Number of rows */
441   protected:
442   UnsizedArrayOf<OffsetTo<Anchor>>
443 		matrixZ;		/* Matrix of offsets to Anchor tables--
444 					 * from beginning of AnchorMatrix table */
445   public:
446   DEFINE_SIZE_ARRAY (2, matrixZ);
447 };
448 
449 
450 struct MarkRecord
451 {
452   friend struct MarkArray;
453 
sanitizeOT::MarkRecord454   bool sanitize (hb_sanitize_context_t *c, const void *base) const
455   {
456     TRACE_SANITIZE (this);
457     return_trace (c->check_struct (this) && markAnchor.sanitize (c, base));
458   }
459 
460   protected:
461   HBUINT16	klass;			/* Class defined for this mark */
462   OffsetTo<Anchor>
463 		markAnchor;		/* Offset to Anchor table--from
464 					 * beginning of MarkArray table */
465   public:
466   DEFINE_SIZE_STATIC (4);
467 };
468 
469 struct MarkArray : ArrayOf<MarkRecord>	/* Array of MarkRecords--in Coverage order */
470 {
applyOT::MarkArray471   bool apply (hb_ot_apply_context_t *c,
472 	      unsigned int mark_index, unsigned int glyph_index,
473 	      const AnchorMatrix &anchors, unsigned int class_count,
474 	      unsigned int glyph_pos) const
475   {
476     TRACE_APPLY (this);
477     hb_buffer_t *buffer = c->buffer;
478     const MarkRecord &record = ArrayOf<MarkRecord>::operator[](mark_index);
479     unsigned int mark_class = record.klass;
480 
481     const Anchor& mark_anchor = this + record.markAnchor;
482     bool found;
483     const Anchor& glyph_anchor = anchors.get_anchor (glyph_index, mark_class, class_count, &found);
484     /* If this subtable doesn't have an anchor for this base and this class,
485      * return false such that the subsequent subtables have a chance at it. */
486     if (unlikely (!found)) return_trace (false);
487 
488     float mark_x, mark_y, base_x, base_y;
489 
490     buffer->unsafe_to_break (glyph_pos, buffer->idx);
491     mark_anchor.get_anchor (c, buffer->cur().codepoint, &mark_x, &mark_y);
492     glyph_anchor.get_anchor (c, buffer->info[glyph_pos].codepoint, &base_x, &base_y);
493 
494     hb_glyph_position_t &o = buffer->cur_pos();
495     o.x_offset = roundf (base_x - mark_x);
496     o.y_offset = roundf (base_y - mark_y);
497     o.attach_type() = ATTACH_TYPE_MARK;
498     o.attach_chain() = (int) glyph_pos - (int) buffer->idx;
499     buffer->scratch_flags |= HB_BUFFER_SCRATCH_FLAG_HAS_GPOS_ATTACHMENT;
500 
501     buffer->idx++;
502     return_trace (true);
503   }
504 
sanitizeOT::MarkArray505   bool sanitize (hb_sanitize_context_t *c) const
506   {
507     TRACE_SANITIZE (this);
508     return_trace (ArrayOf<MarkRecord>::sanitize (c, this));
509   }
510 };
511 
512 
513 /* Lookups */
514 
515 struct SinglePosFormat1
516 {
intersectsOT::SinglePosFormat1517   bool intersects (const hb_set_t *glyphs) const
518   { return (this+coverage).intersects (glyphs); }
519 
collect_glyphsOT::SinglePosFormat1520   void collect_glyphs (hb_collect_glyphs_context_t *c) const
521   { if (unlikely (!(this+coverage).add_coverage (c->input))) return; }
522 
get_coverageOT::SinglePosFormat1523   const Coverage &get_coverage () const { return this+coverage; }
524 
applyOT::SinglePosFormat1525   bool apply (hb_ot_apply_context_t *c) const
526   {
527     TRACE_APPLY (this);
528     hb_buffer_t *buffer = c->buffer;
529     unsigned int index = (this+coverage).get_coverage  (buffer->cur().codepoint);
530     if (likely (index == NOT_COVERED)) return_trace (false);
531 
532     valueFormat.apply_value (c, this, values, buffer->cur_pos());
533 
534     buffer->idx++;
535     return_trace (true);
536   }
537 
538   template<typename Iterator,
539 	   hb_requires (hb_is_iterator (Iterator))>
serializeOT::SinglePosFormat1540   void serialize (hb_serialize_context_t *c,
541 		  Iterator it,
542 		  ValueFormat valFormat)
543   {
544     if (unlikely (!c->extend_min (*this))) return;
545     if (unlikely (!c->check_assign (valueFormat, valFormat))) return;
546 
547     for (const auto &_ : hb_second (*it))
548       c->copy (_);
549 
550     auto glyphs =
551     + it
552     | hb_map_retains_sorting (hb_first)
553     ;
554 
555     coverage.serialize (c, this).serialize (c, glyphs);
556   }
557 
subsetOT::SinglePosFormat1558   bool subset (hb_subset_context_t *c) const
559   {
560     TRACE_SUBSET (this);
561     const hb_set_t &glyphset = *c->plan->glyphset ();
562     const hb_map_t &glyph_map = *c->plan->glyph_map;
563 
564     auto it =
565     + hb_iter (this+coverage)
566     | hb_filter (glyphset)
567     | hb_map_retains_sorting (glyph_map)
568     | hb_zip (hb_repeat (values.as_array (valueFormat.get_len ())))
569     ;
570 
571     bool ret = bool (it);
572     SinglePos_serialize (c->serializer, it, valueFormat);
573     return_trace (ret);
574   }
575 
sanitizeOT::SinglePosFormat1576   bool sanitize (hb_sanitize_context_t *c) const
577   {
578     TRACE_SANITIZE (this);
579     return_trace (c->check_struct (this) &&
580 		  coverage.sanitize (c, this) &&
581 		  valueFormat.sanitize_value (c, this, values));
582   }
583 
584   protected:
585   HBUINT16	format;			/* Format identifier--format = 1 */
586   OffsetTo<Coverage>
587 		coverage;		/* Offset to Coverage table--from
588 					 * beginning of subtable */
589   ValueFormat	valueFormat;		/* Defines the types of data in the
590 					 * ValueRecord */
591   ValueRecord	values;			/* Defines positioning
592 					 * value(s)--applied to all glyphs in
593 					 * the Coverage table */
594   public:
595   DEFINE_SIZE_ARRAY (6, values);
596 };
597 
598 struct SinglePosFormat2
599 {
intersectsOT::SinglePosFormat2600   bool intersects (const hb_set_t *glyphs) const
601   { return (this+coverage).intersects (glyphs); }
602 
collect_glyphsOT::SinglePosFormat2603   void collect_glyphs (hb_collect_glyphs_context_t *c) const
604   { if (unlikely (!(this+coverage).add_coverage (c->input))) return; }
605 
get_coverageOT::SinglePosFormat2606   const Coverage &get_coverage () const { return this+coverage; }
607 
applyOT::SinglePosFormat2608   bool apply (hb_ot_apply_context_t *c) const
609   {
610     TRACE_APPLY (this);
611     hb_buffer_t *buffer = c->buffer;
612     unsigned int index = (this+coverage).get_coverage  (buffer->cur().codepoint);
613     if (likely (index == NOT_COVERED)) return_trace (false);
614 
615     if (likely (index >= valueCount)) return_trace (false);
616 
617     valueFormat.apply_value (c, this,
618 			     &values[index * valueFormat.get_len ()],
619 			     buffer->cur_pos());
620 
621     buffer->idx++;
622     return_trace (true);
623   }
624 
625   template<typename Iterator,
626 	   hb_requires (hb_is_iterator (Iterator))>
serializeOT::SinglePosFormat2627   void serialize (hb_serialize_context_t *c,
628 		  Iterator it,
629 		  ValueFormat valFormat)
630   {
631     if (unlikely (!c->extend_min (*this))) return;
632     if (unlikely (!c->check_assign (valueFormat, valFormat))) return;
633     if (unlikely (!c->check_assign (valueCount, it.len ()))) return;
634 
635     for (const auto iter : it)
636       for (const auto &_ : iter.second)
637 	c->copy (_);
638 
639     auto glyphs =
640     + it
641     | hb_map_retains_sorting (hb_first)
642     ;
643 
644     coverage.serialize (c, this).serialize (c, glyphs);
645   }
646 
subsetOT::SinglePosFormat2647   bool subset (hb_subset_context_t *c) const
648   {
649     TRACE_SUBSET (this);
650     const hb_set_t &glyphset = *c->plan->glyphset ();
651     const hb_map_t &glyph_map = *c->plan->glyph_map;
652 
653     unsigned sub_length = valueFormat.get_len ();
654     auto values_array = values.as_array (valueCount * sub_length);
655 
656     auto it =
657     + hb_zip (this+coverage, hb_range ((unsigned) valueCount))
658     | hb_filter (glyphset, hb_first)
659     | hb_map_retains_sorting ([&] (const hb_pair_t<hb_codepoint_t, unsigned>& _)
660 			      {
661 				return hb_pair (glyph_map[_.first],
662 						values_array.sub_array (_.second * sub_length,
663 									sub_length));
664 			      })
665     ;
666 
667     bool ret = bool (it);
668     SinglePos_serialize (c->serializer, it, valueFormat);
669     return_trace (ret);
670   }
671 
sanitizeOT::SinglePosFormat2672   bool sanitize (hb_sanitize_context_t *c) const
673   {
674     TRACE_SANITIZE (this);
675     return_trace (c->check_struct (this) &&
676 		  coverage.sanitize (c, this) &&
677 		  valueFormat.sanitize_values (c, this, values, valueCount));
678   }
679 
680   protected:
681   HBUINT16	format;			/* Format identifier--format = 2 */
682   OffsetTo<Coverage>
683 		coverage;		/* Offset to Coverage table--from
684 					 * beginning of subtable */
685   ValueFormat	valueFormat;		/* Defines the types of data in the
686 					 * ValueRecord */
687   HBUINT16	valueCount;		/* Number of ValueRecords */
688   ValueRecord	values;			/* Array of ValueRecords--positioning
689 					 * values applied to glyphs */
690   public:
691   DEFINE_SIZE_ARRAY (8, values);
692 };
693 
694 struct SinglePos
695 {
696   template<typename Iterator,
697 	   hb_requires (hb_is_iterator (Iterator))>
get_formatOT::SinglePos698   unsigned get_format (Iterator glyph_val_iter_pairs)
699   {
700     hb_array_t<const Value> first_val_iter = hb_second (*glyph_val_iter_pairs);
701 
702     for (const auto iter : glyph_val_iter_pairs)
703       for (const auto _ : hb_zip (iter.second, first_val_iter))
704 	if (_.first != _.second)
705 	  return 2;
706 
707     return 1;
708   }
709 
710 
711   template<typename Iterator,
712 	   hb_requires (hb_is_iterator (Iterator))>
serializeOT::SinglePos713   void serialize (hb_serialize_context_t *c,
714 		  Iterator glyph_val_iter_pairs,
715 		  ValueFormat valFormat)
716   {
717     if (unlikely (!c->extend_min (u.format))) return;
718     unsigned format = 2;
719 
720     if (glyph_val_iter_pairs) format = get_format (glyph_val_iter_pairs);
721 
722     u.format = format;
723     switch (u.format) {
724     case 1: u.format1.serialize (c, glyph_val_iter_pairs, valFormat);
725 	    return;
726     case 2: u.format2.serialize (c, glyph_val_iter_pairs, valFormat);
727 	    return;
728     default:return;
729     }
730   }
731 
732   template <typename context_t, typename ...Ts>
dispatchOT::SinglePos733   typename context_t::return_t dispatch (context_t *c, Ts&&... ds) const
734   {
735     TRACE_DISPATCH (this, u.format);
736     if (unlikely (!c->may_dispatch (this, &u.format))) return_trace (c->no_dispatch_return_value ());
737     switch (u.format) {
738     case 1: return_trace (c->dispatch (u.format1, hb_forward<Ts> (ds)...));
739     case 2: return_trace (c->dispatch (u.format2, hb_forward<Ts> (ds)...));
740     default:return_trace (c->default_return_value ());
741     }
742   }
743 
744   protected:
745   union {
746   HBUINT16		format;		/* Format identifier */
747   SinglePosFormat1	format1;
748   SinglePosFormat2	format2;
749   } u;
750 };
751 
752 template<typename Iterator>
753 static inline void
SinglePos_serialize(hb_serialize_context_t * c,Iterator it,ValueFormat valFormat)754 SinglePos_serialize (hb_serialize_context_t *c,
755 		     Iterator it,
756 		     ValueFormat valFormat)
757 { c->start_embed<SinglePos> ()->serialize (c, it, valFormat); }
758 
759 
760 struct PairValueRecord
761 {
762   friend struct PairSet;
763 
serializeOT::PairValueRecord764   bool serialize (hb_serialize_context_t *c,
765                   unsigned length,
766                   const hb_map_t &glyph_map) const
767   {
768     TRACE_SERIALIZE (this);
769     auto *out = c->start_embed (*this);
770     if (unlikely (!c->extend_min (out))) return_trace (false);
771 
772     out->secondGlyph = glyph_map[secondGlyph];
773     return_trace (c->copy (values, length));
774   }
775 
776   protected:
777   HBGlyphID	secondGlyph;		/* GlyphID of second glyph in the
778 					 * pair--first glyph is listed in the
779 					 * Coverage table */
780   ValueRecord	values;			/* Positioning data for the first glyph
781 					 * followed by for second glyph */
782   public:
783   DEFINE_SIZE_ARRAY (2, values);
784 };
785 
786 struct PairSet
787 {
788   friend struct PairPosFormat1;
789 
intersectsOT::PairSet790   bool intersects (const hb_set_t *glyphs,
791 		   const ValueFormat *valueFormats) const
792   {
793     unsigned int len1 = valueFormats[0].get_len ();
794     unsigned int len2 = valueFormats[1].get_len ();
795     unsigned int record_size = HBUINT16::static_size * (1 + len1 + len2);
796 
797     const PairValueRecord *record = &firstPairValueRecord;
798     unsigned int count = len;
799     for (unsigned int i = 0; i < count; i++)
800     {
801       if (glyphs->has (record->secondGlyph))
802 	return true;
803       record = &StructAtOffset<const PairValueRecord> (record, record_size);
804     }
805     return false;
806   }
807 
collect_glyphsOT::PairSet808   void collect_glyphs (hb_collect_glyphs_context_t *c,
809 			      const ValueFormat *valueFormats) const
810   {
811     unsigned int len1 = valueFormats[0].get_len ();
812     unsigned int len2 = valueFormats[1].get_len ();
813     unsigned int record_size = HBUINT16::static_size * (1 + len1 + len2);
814 
815     const PairValueRecord *record = &firstPairValueRecord;
816     c->input->add_array (&record->secondGlyph, len, record_size);
817   }
818 
applyOT::PairSet819   bool apply (hb_ot_apply_context_t *c,
820 		     const ValueFormat *valueFormats,
821 		     unsigned int pos) const
822   {
823     TRACE_APPLY (this);
824     hb_buffer_t *buffer = c->buffer;
825     unsigned int len1 = valueFormats[0].get_len ();
826     unsigned int len2 = valueFormats[1].get_len ();
827     unsigned int record_size = HBUINT16::static_size * (1 + len1 + len2);
828 
829     unsigned int count = len;
830 
831     /* Hand-coded bsearch. */
832     if (unlikely (!count))
833       return_trace (false);
834     hb_codepoint_t x = buffer->info[pos].codepoint;
835     int min = 0, max = (int) count - 1;
836     while (min <= max)
837     {
838       int mid = ((unsigned int) min + (unsigned int) max) / 2;
839       const PairValueRecord *record = &StructAtOffset<PairValueRecord> (&firstPairValueRecord, record_size * mid);
840       hb_codepoint_t mid_x = record->secondGlyph;
841       if (x < mid_x)
842 	max = mid - 1;
843       else if (x > mid_x)
844 	min = mid + 1;
845       else
846       {
847 	/* Note the intentional use of "|" instead of short-circuit "||". */
848 	if (valueFormats[0].apply_value (c, this, &record->values[0], buffer->cur_pos()) |
849 	    valueFormats[1].apply_value (c, this, &record->values[len1], buffer->pos[pos]))
850 	  buffer->unsafe_to_break (buffer->idx, pos + 1);
851 	if (len2)
852 	  pos++;
853 	buffer->idx = pos;
854 	return_trace (true);
855       }
856     }
857 
858     return_trace (false);
859   }
860 
subsetOT::PairSet861   bool subset (hb_subset_context_t *c,
862                const ValueFormat valueFormats[2]) const
863   {
864     TRACE_SUBSET (this);
865     auto snap = c->serializer->snapshot ();
866 
867     auto *out = c->serializer->start_embed (*this);
868     if (unlikely (!c->serializer->extend_min (out))) return_trace (false);
869     out->len = 0;
870 
871     const hb_set_t &glyphset = *c->plan->glyphset ();
872     const hb_map_t &glyph_map = *c->plan->glyph_map;
873 
874     unsigned len1 = valueFormats[0].get_len ();
875     unsigned len2 = valueFormats[1].get_len ();
876     unsigned record_size = HBUINT16::static_size + Value::static_size * (len1 + len2);
877 
878     const PairValueRecord *record = &firstPairValueRecord;
879     unsigned count = len, num = 0;
880     for (unsigned i = 0; i < count; i++)
881     {
882       if (!glyphset.has (record->secondGlyph)) continue;
883       if (record->serialize (c->serializer, len1 + len2, glyph_map)) num++;
884       record = &StructAtOffset<const PairValueRecord> (record, record_size);
885     }
886 
887     out->len = num;
888     if (!num) c->serializer->revert (snap);
889     return_trace (num);
890   }
891 
892   struct sanitize_closure_t
893   {
894     const void *base;
895     const ValueFormat *valueFormats;
896     unsigned int len1; /* valueFormats[0].get_len() */
897     unsigned int stride; /* 1 + len1 + len2 */
898   };
899 
sanitizeOT::PairSet900   bool sanitize (hb_sanitize_context_t *c, const sanitize_closure_t *closure) const
901   {
902     TRACE_SANITIZE (this);
903     if (!(c->check_struct (this)
904        && c->check_range (&firstPairValueRecord,
905 			  len,
906 			  HBUINT16::static_size,
907 			  closure->stride))) return_trace (false);
908 
909     unsigned int count = len;
910     const PairValueRecord *record = &firstPairValueRecord;
911     return_trace (closure->valueFormats[0].sanitize_values_stride_unsafe (c, closure->base, &record->values[0], count, closure->stride) &&
912 		  closure->valueFormats[1].sanitize_values_stride_unsafe (c, closure->base, &record->values[closure->len1], count, closure->stride));
913   }
914 
915   protected:
916   HBUINT16		len;	/* Number of PairValueRecords */
917   PairValueRecord	firstPairValueRecord;
918 				/* Array of PairValueRecords--ordered
919 				 * by GlyphID of the second glyph */
920   public:
921   DEFINE_SIZE_MIN (2);
922 };
923 
924 struct PairPosFormat1
925 {
intersectsOT::PairPosFormat1926   bool intersects (const hb_set_t *glyphs) const
927   {
928     return
929     + hb_zip (this+coverage, pairSet)
930     | hb_filter (*glyphs, hb_first)
931     | hb_map (hb_second)
932     | hb_map ([glyphs, this] (const OffsetTo<PairSet> &_)
933 	      { return (this+_).intersects (glyphs, valueFormat); })
934     | hb_any
935     ;
936   }
937 
collect_glyphsOT::PairPosFormat1938   void collect_glyphs (hb_collect_glyphs_context_t *c) const
939   {
940     if (unlikely (!(this+coverage).add_coverage (c->input))) return;
941     unsigned int count = pairSet.len;
942     for (unsigned int i = 0; i < count; i++)
943       (this+pairSet[i]).collect_glyphs (c, valueFormat);
944   }
945 
get_coverageOT::PairPosFormat1946   const Coverage &get_coverage () const { return this+coverage; }
947 
applyOT::PairPosFormat1948   bool apply (hb_ot_apply_context_t *c) const
949   {
950     TRACE_APPLY (this);
951     hb_buffer_t *buffer = c->buffer;
952     unsigned int index = (this+coverage).get_coverage  (buffer->cur().codepoint);
953     if (likely (index == NOT_COVERED)) return_trace (false);
954 
955     hb_ot_apply_context_t::skipping_iterator_t &skippy_iter = c->iter_input;
956     skippy_iter.reset (buffer->idx, 1);
957     if (!skippy_iter.next ()) return_trace (false);
958 
959     return_trace ((this+pairSet[index]).apply (c, valueFormat, skippy_iter.idx));
960   }
961 
subsetOT::PairPosFormat1962   bool subset (hb_subset_context_t *c) const
963   {
964     TRACE_SUBSET (this);
965 
966     const hb_set_t &glyphset = *c->plan->glyphset ();
967     const hb_map_t &glyph_map = *c->plan->glyph_map;
968 
969     auto *out = c->serializer->start_embed (*this);
970     if (unlikely (!c->serializer->extend_min (out))) return_trace (false);
971     out->format = format;
972     out->valueFormat[0] = valueFormat[0];
973     out->valueFormat[1] = valueFormat[1];
974 
975     hb_sorted_vector_t<hb_codepoint_t> new_coverage;
976 
977     + hb_zip (this+coverage, pairSet)
978     | hb_filter (glyphset, hb_first)
979     | hb_filter ([this, c, out] (const OffsetTo<PairSet>& _)
980 		 {
981 		   auto *o = out->pairSet.serialize_append (c->serializer);
982 		   if (unlikely (!o)) return false;
983 		   auto snap = c->serializer->snapshot ();
984 		   bool ret = o->serialize_subset (c, _, this, out, valueFormat);
985 		   if (!ret)
986 		   {
987 		     out->pairSet.pop ();
988 		     c->serializer->revert (snap);
989 		   }
990 		   return ret;
991 		 },
992 		 hb_second)
993     | hb_map (hb_first)
994     | hb_map (glyph_map)
995     | hb_sink (new_coverage)
996     ;
997 
998     out->coverage.serialize (c->serializer, out)
999 		 .serialize (c->serializer, new_coverage.iter ());
1000 
1001     return_trace (bool (new_coverage));
1002   }
1003 
sanitizeOT::PairPosFormat11004   bool sanitize (hb_sanitize_context_t *c) const
1005   {
1006     TRACE_SANITIZE (this);
1007 
1008     if (!c->check_struct (this)) return_trace (false);
1009 
1010     unsigned int len1 = valueFormat[0].get_len ();
1011     unsigned int len2 = valueFormat[1].get_len ();
1012     PairSet::sanitize_closure_t closure =
1013     {
1014       this,
1015       valueFormat,
1016       len1,
1017       1 + len1 + len2
1018     };
1019 
1020     return_trace (coverage.sanitize (c, this) && pairSet.sanitize (c, this, &closure));
1021   }
1022 
1023   protected:
1024   HBUINT16	format;			/* Format identifier--format = 1 */
1025   OffsetTo<Coverage>
1026 		coverage;		/* Offset to Coverage table--from
1027 					 * beginning of subtable */
1028   ValueFormat	valueFormat[2];		/* [0] Defines the types of data in
1029 					 * ValueRecord1--for the first glyph
1030 					 * in the pair--may be zero (0) */
1031 					/* [1] Defines the types of data in
1032 					 * ValueRecord2--for the second glyph
1033 					 * in the pair--may be zero (0) */
1034   OffsetArrayOf<PairSet>
1035 		pairSet;		/* Array of PairSet tables
1036 					 * ordered by Coverage Index */
1037   public:
1038   DEFINE_SIZE_ARRAY (10, pairSet);
1039 };
1040 
1041 struct PairPosFormat2
1042 {
intersectsOT::PairPosFormat21043   bool intersects (const hb_set_t *glyphs) const
1044   {
1045     return (this+coverage).intersects (glyphs) &&
1046 	   (this+classDef2).intersects (glyphs);
1047   }
1048 
collect_glyphsOT::PairPosFormat21049   void collect_glyphs (hb_collect_glyphs_context_t *c) const
1050   {
1051     if (unlikely (!(this+coverage).add_coverage (c->input))) return;
1052     if (unlikely (!(this+classDef2).add_coverage (c->input))) return;
1053   }
1054 
get_coverageOT::PairPosFormat21055   const Coverage &get_coverage () const { return this+coverage; }
1056 
applyOT::PairPosFormat21057   bool apply (hb_ot_apply_context_t *c) const
1058   {
1059     TRACE_APPLY (this);
1060     hb_buffer_t *buffer = c->buffer;
1061     unsigned int index = (this+coverage).get_coverage  (buffer->cur().codepoint);
1062     if (likely (index == NOT_COVERED)) return_trace (false);
1063 
1064     hb_ot_apply_context_t::skipping_iterator_t &skippy_iter = c->iter_input;
1065     skippy_iter.reset (buffer->idx, 1);
1066     if (!skippy_iter.next ()) return_trace (false);
1067 
1068     unsigned int len1 = valueFormat1.get_len ();
1069     unsigned int len2 = valueFormat2.get_len ();
1070     unsigned int record_len = len1 + len2;
1071 
1072     unsigned int klass1 = (this+classDef1).get_class (buffer->cur().codepoint);
1073     unsigned int klass2 = (this+classDef2).get_class (buffer->info[skippy_iter.idx].codepoint);
1074     if (unlikely (klass1 >= class1Count || klass2 >= class2Count)) return_trace (false);
1075 
1076     const Value *v = &values[record_len * (klass1 * class2Count + klass2)];
1077     /* Note the intentional use of "|" instead of short-circuit "||". */
1078     if (valueFormat1.apply_value (c, this, v, buffer->cur_pos()) |
1079 	valueFormat2.apply_value (c, this, v + len1, buffer->pos[skippy_iter.idx]))
1080       buffer->unsafe_to_break (buffer->idx, skippy_iter.idx + 1);
1081 
1082     buffer->idx = skippy_iter.idx;
1083     if (len2)
1084       buffer->idx++;
1085 
1086     return_trace (true);
1087   }
1088 
subsetOT::PairPosFormat21089   bool subset (hb_subset_context_t *c) const
1090   {
1091     TRACE_SUBSET (this);
1092     auto *out = c->serializer->start_embed (*this);
1093     if (unlikely (!c->serializer->extend_min (out))) return_trace (false);
1094     out->format = format;
1095     out->valueFormat1 = valueFormat1;
1096     out->valueFormat2 = valueFormat2;
1097 
1098     hb_map_t klass1_map;
1099     out->classDef1.serialize_subset (c, classDef1, this, out, &klass1_map);
1100     out->class1Count = klass1_map.get_population ();
1101 
1102     hb_map_t klass2_map;
1103     out->classDef2.serialize_subset (c, classDef2, this, out, &klass2_map);
1104     out->class2Count = klass2_map.get_population ();
1105 
1106     unsigned record_len = valueFormat1.get_len () + valueFormat2.get_len ();
1107 
1108     + hb_range ((unsigned) class1Count)
1109     | hb_filter (klass1_map)
1110     | hb_apply ([&] (const unsigned class1_idx)
1111                 {
1112                   + hb_range ((unsigned) class2Count)
1113                   | hb_filter (klass2_map)
1114                   | hb_apply ([&] (const unsigned class2_idx)
1115                               {
1116                                 unsigned idx = (class1_idx * (unsigned) class2Count + class2_idx) * record_len;
1117                                 for (unsigned i = 0; i < record_len; i++)
1118                                   c->serializer->copy (values[idx+i]);
1119                               })
1120                   ;
1121                 })
1122     ;
1123 
1124     const hb_set_t &glyphset = *c->plan->glyphset ();
1125     const hb_map_t &glyph_map = *c->plan->glyph_map;
1126 
1127     auto it =
1128     + hb_iter (this+coverage)
1129     | hb_filter (glyphset)
1130     | hb_map_retains_sorting (glyph_map)
1131     ;
1132 
1133     out->coverage.serialize (c->serializer, out).serialize (c->serializer, it);
1134     return_trace (out->class1Count && out->class2Count && bool (it));
1135   }
1136 
sanitizeOT::PairPosFormat21137   bool sanitize (hb_sanitize_context_t *c) const
1138   {
1139     TRACE_SANITIZE (this);
1140     if (!(c->check_struct (this)
1141        && coverage.sanitize (c, this)
1142        && classDef1.sanitize (c, this)
1143        && classDef2.sanitize (c, this))) return_trace (false);
1144 
1145     unsigned int len1 = valueFormat1.get_len ();
1146     unsigned int len2 = valueFormat2.get_len ();
1147     unsigned int stride = len1 + len2;
1148     unsigned int record_size = valueFormat1.get_size () + valueFormat2.get_size ();
1149     unsigned int count = (unsigned int) class1Count * (unsigned int) class2Count;
1150     return_trace (c->check_range ((const void *) values,
1151 				  count,
1152 				  record_size) &&
1153 		  valueFormat1.sanitize_values_stride_unsafe (c, this, &values[0], count, stride) &&
1154 		  valueFormat2.sanitize_values_stride_unsafe (c, this, &values[len1], count, stride));
1155   }
1156 
1157   protected:
1158   HBUINT16	format;			/* Format identifier--format = 2 */
1159   OffsetTo<Coverage>
1160 		coverage;		/* Offset to Coverage table--from
1161 					 * beginning of subtable */
1162   ValueFormat	valueFormat1;		/* ValueRecord definition--for the
1163 					 * first glyph of the pair--may be zero
1164 					 * (0) */
1165   ValueFormat	valueFormat2;		/* ValueRecord definition--for the
1166 					 * second glyph of the pair--may be
1167 					 * zero (0) */
1168   OffsetTo<ClassDef>
1169 		classDef1;		/* Offset to ClassDef table--from
1170 					 * beginning of PairPos subtable--for
1171 					 * the first glyph of the pair */
1172   OffsetTo<ClassDef>
1173 		classDef2;		/* Offset to ClassDef table--from
1174 					 * beginning of PairPos subtable--for
1175 					 * the second glyph of the pair */
1176   HBUINT16	class1Count;		/* Number of classes in ClassDef1
1177 					 * table--includes Class0 */
1178   HBUINT16	class2Count;		/* Number of classes in ClassDef2
1179 					 * table--includes Class0 */
1180   ValueRecord	values;			/* Matrix of value pairs:
1181 					 * class1-major, class2-minor,
1182 					 * Each entry has value1 and value2 */
1183   public:
1184   DEFINE_SIZE_ARRAY (16, values);
1185 };
1186 
1187 struct PairPos
1188 {
1189   template <typename context_t, typename ...Ts>
dispatchOT::PairPos1190   typename context_t::return_t dispatch (context_t *c, Ts&&... ds) const
1191   {
1192     TRACE_DISPATCH (this, u.format);
1193     if (unlikely (!c->may_dispatch (this, &u.format))) return_trace (c->no_dispatch_return_value ());
1194     switch (u.format) {
1195     case 1: return_trace (c->dispatch (u.format1, hb_forward<Ts> (ds)...));
1196     case 2: return_trace (c->dispatch (u.format2, hb_forward<Ts> (ds)...));
1197     default:return_trace (c->default_return_value ());
1198     }
1199   }
1200 
1201   protected:
1202   union {
1203   HBUINT16		format;		/* Format identifier */
1204   PairPosFormat1	format1;
1205   PairPosFormat2	format2;
1206   } u;
1207 };
1208 
1209 
1210 struct EntryExitRecord
1211 {
1212   friend struct CursivePosFormat1;
1213 
sanitizeOT::EntryExitRecord1214   bool sanitize (hb_sanitize_context_t *c, const void *base) const
1215   {
1216     TRACE_SANITIZE (this);
1217     return_trace (entryAnchor.sanitize (c, base) && exitAnchor.sanitize (c, base));
1218   }
1219 
copyOT::EntryExitRecord1220   EntryExitRecord* copy (hb_serialize_context_t *c,
1221 			 const void *src_base,
1222 			 const void *dst_base) const
1223   {
1224     TRACE_SERIALIZE (this);
1225     auto *out = c->embed (this);
1226     if (unlikely (!out)) return_trace (nullptr);
1227 
1228     out->entryAnchor.serialize_copy (c, entryAnchor, src_base, dst_base);
1229     out->exitAnchor.serialize_copy (c, exitAnchor, src_base, dst_base);
1230     return_trace (out);
1231   }
1232 
1233   protected:
1234   OffsetTo<Anchor>
1235 		entryAnchor;		/* Offset to EntryAnchor table--from
1236 					 * beginning of CursivePos
1237 					 * subtable--may be NULL */
1238   OffsetTo<Anchor>
1239 		exitAnchor;		/* Offset to ExitAnchor table--from
1240 					 * beginning of CursivePos
1241 					 * subtable--may be NULL */
1242   public:
1243   DEFINE_SIZE_STATIC (4);
1244 };
1245 
1246 static void
1247 reverse_cursive_minor_offset (hb_glyph_position_t *pos, unsigned int i, hb_direction_t direction, unsigned int new_parent);
1248 
1249 struct CursivePosFormat1
1250 {
intersectsOT::CursivePosFormat11251   bool intersects (const hb_set_t *glyphs) const
1252   { return (this+coverage).intersects (glyphs); }
1253 
collect_glyphsOT::CursivePosFormat11254   void collect_glyphs (hb_collect_glyphs_context_t *c) const
1255   { if (unlikely (!(this+coverage).add_coverage (c->input))) return; }
1256 
get_coverageOT::CursivePosFormat11257   const Coverage &get_coverage () const { return this+coverage; }
1258 
applyOT::CursivePosFormat11259   bool apply (hb_ot_apply_context_t *c) const
1260   {
1261     TRACE_APPLY (this);
1262     hb_buffer_t *buffer = c->buffer;
1263 
1264     const EntryExitRecord &this_record = entryExitRecord[(this+coverage).get_coverage  (buffer->cur().codepoint)];
1265     if (!this_record.entryAnchor) return_trace (false);
1266 
1267     hb_ot_apply_context_t::skipping_iterator_t &skippy_iter = c->iter_input;
1268     skippy_iter.reset (buffer->idx, 1);
1269     if (!skippy_iter.prev ()) return_trace (false);
1270 
1271     const EntryExitRecord &prev_record = entryExitRecord[(this+coverage).get_coverage  (buffer->info[skippy_iter.idx].codepoint)];
1272     if (!prev_record.exitAnchor) return_trace (false);
1273 
1274     unsigned int i = skippy_iter.idx;
1275     unsigned int j = buffer->idx;
1276 
1277     buffer->unsafe_to_break (i, j);
1278     float entry_x, entry_y, exit_x, exit_y;
1279     (this+prev_record.exitAnchor).get_anchor (c, buffer->info[i].codepoint, &exit_x, &exit_y);
1280     (this+this_record.entryAnchor).get_anchor (c, buffer->info[j].codepoint, &entry_x, &entry_y);
1281 
1282     hb_glyph_position_t *pos = buffer->pos;
1283 
1284     hb_position_t d;
1285     /* Main-direction adjustment */
1286     switch (c->direction) {
1287       case HB_DIRECTION_LTR:
1288 	pos[i].x_advance  = roundf (exit_x) + pos[i].x_offset;
1289 
1290 	d = roundf (entry_x) + pos[j].x_offset;
1291 	pos[j].x_advance -= d;
1292 	pos[j].x_offset  -= d;
1293 	break;
1294       case HB_DIRECTION_RTL:
1295 	d = roundf (exit_x) + pos[i].x_offset;
1296 	pos[i].x_advance -= d;
1297 	pos[i].x_offset  -= d;
1298 
1299 	pos[j].x_advance  = roundf (entry_x) + pos[j].x_offset;
1300 	break;
1301       case HB_DIRECTION_TTB:
1302 	pos[i].y_advance  = roundf (exit_y) + pos[i].y_offset;
1303 
1304 	d = roundf (entry_y) + pos[j].y_offset;
1305 	pos[j].y_advance -= d;
1306 	pos[j].y_offset  -= d;
1307 	break;
1308       case HB_DIRECTION_BTT:
1309 	d = roundf (exit_y) + pos[i].y_offset;
1310 	pos[i].y_advance -= d;
1311 	pos[i].y_offset  -= d;
1312 
1313 	pos[j].y_advance  = roundf (entry_y);
1314 	break;
1315       case HB_DIRECTION_INVALID:
1316       default:
1317 	break;
1318     }
1319 
1320     /* Cross-direction adjustment */
1321 
1322     /* We attach child to parent (think graph theory and rooted trees whereas
1323      * the root stays on baseline and each node aligns itself against its
1324      * parent.
1325      *
1326      * Optimize things for the case of RightToLeft, as that's most common in
1327      * Arabic. */
1328     unsigned int child  = i;
1329     unsigned int parent = j;
1330     hb_position_t x_offset = entry_x - exit_x;
1331     hb_position_t y_offset = entry_y - exit_y;
1332     if  (!(c->lookup_props & LookupFlag::RightToLeft))
1333     {
1334       unsigned int k = child;
1335       child = parent;
1336       parent = k;
1337       x_offset = -x_offset;
1338       y_offset = -y_offset;
1339     }
1340 
1341     /* If child was already connected to someone else, walk through its old
1342      * chain and reverse the link direction, such that the whole tree of its
1343      * previous connection now attaches to new parent.  Watch out for case
1344      * where new parent is on the path from old chain...
1345      */
1346     reverse_cursive_minor_offset (pos, child, c->direction, parent);
1347 
1348     pos[child].attach_type() = ATTACH_TYPE_CURSIVE;
1349     pos[child].attach_chain() = (int) parent - (int) child;
1350     buffer->scratch_flags |= HB_BUFFER_SCRATCH_FLAG_HAS_GPOS_ATTACHMENT;
1351     if (likely (HB_DIRECTION_IS_HORIZONTAL (c->direction)))
1352       pos[child].y_offset = y_offset;
1353     else
1354       pos[child].x_offset = x_offset;
1355 
1356     buffer->idx++;
1357     return_trace (true);
1358   }
1359 
1360   template <typename Iterator,
1361 	    hb_requires (hb_is_iterator (Iterator))>
serializeOT::CursivePosFormat11362   void serialize (hb_serialize_context_t *c,
1363 		  Iterator it,
1364 		  const void *src_base)
1365   {
1366     if (unlikely (!c->extend_min ((*this)))) return;
1367     this->format = 1;
1368     this->entryExitRecord.len = it.len ();
1369 
1370     for (const EntryExitRecord& entry_record : + it
1371 					       | hb_map (hb_second))
1372       c->copy (entry_record, src_base, this);
1373 
1374     auto glyphs =
1375     + it
1376     | hb_map_retains_sorting (hb_first)
1377     ;
1378 
1379     coverage.serialize (c, this).serialize (c, glyphs);
1380   }
1381 
subsetOT::CursivePosFormat11382   bool subset (hb_subset_context_t *c) const
1383   {
1384     TRACE_SUBSET (this);
1385     const hb_set_t &glyphset = *c->plan->glyphset ();
1386     const hb_map_t &glyph_map = *c->plan->glyph_map;
1387 
1388     auto *out = c->serializer->start_embed (*this);
1389     if (unlikely (!out)) return_trace (false);
1390 
1391     auto it =
1392     + hb_zip (this+coverage, entryExitRecord)
1393     | hb_filter (glyphset, hb_first)
1394     | hb_map_retains_sorting ([&] (hb_pair_t<hb_codepoint_t, const EntryExitRecord&> p) -> hb_pair_t<hb_codepoint_t, const EntryExitRecord&>
1395 			      { return hb_pair (glyph_map[p.first], p.second);})
1396     ;
1397 
1398     bool ret = bool (it);
1399     out->serialize (c->serializer, it, this);
1400     return_trace (ret);
1401   }
1402 
sanitizeOT::CursivePosFormat11403   bool sanitize (hb_sanitize_context_t *c) const
1404   {
1405     TRACE_SANITIZE (this);
1406     return_trace (coverage.sanitize (c, this) && entryExitRecord.sanitize (c, this));
1407   }
1408 
1409   protected:
1410   HBUINT16	format;			/* Format identifier--format = 1 */
1411   OffsetTo<Coverage>
1412 		coverage;		/* Offset to Coverage table--from
1413 					 * beginning of subtable */
1414   ArrayOf<EntryExitRecord>
1415 		entryExitRecord;	/* Array of EntryExit records--in
1416 					 * Coverage Index order */
1417   public:
1418   DEFINE_SIZE_ARRAY (6, entryExitRecord);
1419 };
1420 
1421 struct CursivePos
1422 {
1423   template <typename context_t, typename ...Ts>
dispatchOT::CursivePos1424   typename context_t::return_t dispatch (context_t *c, Ts&&... ds) const
1425   {
1426     TRACE_DISPATCH (this, u.format);
1427     if (unlikely (!c->may_dispatch (this, &u.format))) return_trace (c->no_dispatch_return_value ());
1428     switch (u.format) {
1429     case 1: return_trace (c->dispatch (u.format1, hb_forward<Ts> (ds)...));
1430     default:return_trace (c->default_return_value ());
1431     }
1432   }
1433 
1434   protected:
1435   union {
1436   HBUINT16		format;		/* Format identifier */
1437   CursivePosFormat1	format1;
1438   } u;
1439 };
1440 
1441 
1442 typedef AnchorMatrix BaseArray;		/* base-major--
1443 					 * in order of BaseCoverage Index--,
1444 					 * mark-minor--
1445 					 * ordered by class--zero-based. */
1446 
1447 struct MarkBasePosFormat1
1448 {
intersectsOT::MarkBasePosFormat11449   bool intersects (const hb_set_t *glyphs) const
1450   { return (this+markCoverage).intersects (glyphs) &&
1451 	   (this+baseCoverage).intersects (glyphs); }
1452 
collect_glyphsOT::MarkBasePosFormat11453   void collect_glyphs (hb_collect_glyphs_context_t *c) const
1454   {
1455     if (unlikely (!(this+markCoverage).add_coverage (c->input))) return;
1456     if (unlikely (!(this+baseCoverage).add_coverage (c->input))) return;
1457   }
1458 
get_coverageOT::MarkBasePosFormat11459   const Coverage &get_coverage () const { return this+markCoverage; }
1460 
applyOT::MarkBasePosFormat11461   bool apply (hb_ot_apply_context_t *c) const
1462   {
1463     TRACE_APPLY (this);
1464     hb_buffer_t *buffer = c->buffer;
1465     unsigned int mark_index = (this+markCoverage).get_coverage  (buffer->cur().codepoint);
1466     if (likely (mark_index == NOT_COVERED)) return_trace (false);
1467 
1468     /* Now we search backwards for a non-mark glyph */
1469     hb_ot_apply_context_t::skipping_iterator_t &skippy_iter = c->iter_input;
1470     skippy_iter.reset (buffer->idx, 1);
1471     skippy_iter.set_lookup_props (LookupFlag::IgnoreMarks);
1472     do {
1473       if (!skippy_iter.prev ()) return_trace (false);
1474       /* We only want to attach to the first of a MultipleSubst sequence.
1475        * https://github.com/harfbuzz/harfbuzz/issues/740
1476        * Reject others...
1477        * ...but stop if we find a mark in the MultipleSubst sequence:
1478        * https://github.com/harfbuzz/harfbuzz/issues/1020 */
1479       if (!_hb_glyph_info_multiplied (&buffer->info[skippy_iter.idx]) ||
1480 	  0 == _hb_glyph_info_get_lig_comp (&buffer->info[skippy_iter.idx]) ||
1481 	  (skippy_iter.idx == 0 ||
1482 	   _hb_glyph_info_is_mark (&buffer->info[skippy_iter.idx - 1]) ||
1483 	   _hb_glyph_info_get_lig_id (&buffer->info[skippy_iter.idx]) !=
1484 	   _hb_glyph_info_get_lig_id (&buffer->info[skippy_iter.idx - 1]) ||
1485 	   _hb_glyph_info_get_lig_comp (&buffer->info[skippy_iter.idx]) !=
1486 	   _hb_glyph_info_get_lig_comp (&buffer->info[skippy_iter.idx - 1]) + 1
1487 	   ))
1488 	break;
1489       skippy_iter.reject ();
1490     } while (true);
1491 
1492     /* Checking that matched glyph is actually a base glyph by GDEF is too strong; disabled */
1493     //if (!_hb_glyph_info_is_base_glyph (&buffer->info[skippy_iter.idx])) { return_trace (false); }
1494 
1495     unsigned int base_index = (this+baseCoverage).get_coverage  (buffer->info[skippy_iter.idx].codepoint);
1496     if (base_index == NOT_COVERED) return_trace (false);
1497 
1498     return_trace ((this+markArray).apply (c, mark_index, base_index, this+baseArray, classCount, skippy_iter.idx));
1499   }
1500 
subsetOT::MarkBasePosFormat11501   bool subset (hb_subset_context_t *c) const
1502   {
1503     TRACE_SUBSET (this);
1504     // TODO(subset)
1505     return_trace (false);
1506   }
1507 
sanitizeOT::MarkBasePosFormat11508   bool sanitize (hb_sanitize_context_t *c) const
1509   {
1510     TRACE_SANITIZE (this);
1511     return_trace (c->check_struct (this) &&
1512 		  markCoverage.sanitize (c, this) &&
1513 		  baseCoverage.sanitize (c, this) &&
1514 		  markArray.sanitize (c, this) &&
1515 		  baseArray.sanitize (c, this, (unsigned int) classCount));
1516   }
1517 
1518   protected:
1519   HBUINT16	format;			/* Format identifier--format = 1 */
1520   OffsetTo<Coverage>
1521 		markCoverage;		/* Offset to MarkCoverage table--from
1522 					 * beginning of MarkBasePos subtable */
1523   OffsetTo<Coverage>
1524 		baseCoverage;		/* Offset to BaseCoverage table--from
1525 					 * beginning of MarkBasePos subtable */
1526   HBUINT16	classCount;		/* Number of classes defined for marks */
1527   OffsetTo<MarkArray>
1528 		markArray;		/* Offset to MarkArray table--from
1529 					 * beginning of MarkBasePos subtable */
1530   OffsetTo<BaseArray>
1531 		baseArray;		/* Offset to BaseArray table--from
1532 					 * beginning of MarkBasePos subtable */
1533   public:
1534   DEFINE_SIZE_STATIC (12);
1535 };
1536 
1537 struct MarkBasePos
1538 {
1539   template <typename context_t, typename ...Ts>
dispatchOT::MarkBasePos1540   typename context_t::return_t dispatch (context_t *c, Ts&&... ds) const
1541   {
1542     TRACE_DISPATCH (this, u.format);
1543     if (unlikely (!c->may_dispatch (this, &u.format))) return_trace (c->no_dispatch_return_value ());
1544     switch (u.format) {
1545     case 1: return_trace (c->dispatch (u.format1, hb_forward<Ts> (ds)...));
1546     default:return_trace (c->default_return_value ());
1547     }
1548   }
1549 
1550   protected:
1551   union {
1552   HBUINT16		format;		/* Format identifier */
1553   MarkBasePosFormat1	format1;
1554   } u;
1555 };
1556 
1557 
1558 typedef AnchorMatrix LigatureAttach;	/* component-major--
1559 					 * in order of writing direction--,
1560 					 * mark-minor--
1561 					 * ordered by class--zero-based. */
1562 
1563 typedef OffsetListOf<LigatureAttach> LigatureArray;
1564 					/* Array of LigatureAttach
1565 					 * tables ordered by
1566 					 * LigatureCoverage Index */
1567 
1568 struct MarkLigPosFormat1
1569 {
intersectsOT::MarkLigPosFormat11570   bool intersects (const hb_set_t *glyphs) const
1571   { return (this+markCoverage).intersects (glyphs) &&
1572 	   (this+ligatureCoverage).intersects (glyphs); }
1573 
collect_glyphsOT::MarkLigPosFormat11574   void collect_glyphs (hb_collect_glyphs_context_t *c) const
1575   {
1576     if (unlikely (!(this+markCoverage).add_coverage (c->input))) return;
1577     if (unlikely (!(this+ligatureCoverage).add_coverage (c->input))) return;
1578   }
1579 
get_coverageOT::MarkLigPosFormat11580   const Coverage &get_coverage () const { return this+markCoverage; }
1581 
applyOT::MarkLigPosFormat11582   bool apply (hb_ot_apply_context_t *c) const
1583   {
1584     TRACE_APPLY (this);
1585     hb_buffer_t *buffer = c->buffer;
1586     unsigned int mark_index = (this+markCoverage).get_coverage  (buffer->cur().codepoint);
1587     if (likely (mark_index == NOT_COVERED)) return_trace (false);
1588 
1589     /* Now we search backwards for a non-mark glyph */
1590     hb_ot_apply_context_t::skipping_iterator_t &skippy_iter = c->iter_input;
1591     skippy_iter.reset (buffer->idx, 1);
1592     skippy_iter.set_lookup_props (LookupFlag::IgnoreMarks);
1593     if (!skippy_iter.prev ()) return_trace (false);
1594 
1595     /* Checking that matched glyph is actually a ligature by GDEF is too strong; disabled */
1596     //if (!_hb_glyph_info_is_ligature (&buffer->info[skippy_iter.idx])) { return_trace (false); }
1597 
1598     unsigned int j = skippy_iter.idx;
1599     unsigned int lig_index = (this+ligatureCoverage).get_coverage  (buffer->info[j].codepoint);
1600     if (lig_index == NOT_COVERED) return_trace (false);
1601 
1602     const LigatureArray& lig_array = this+ligatureArray;
1603     const LigatureAttach& lig_attach = lig_array[lig_index];
1604 
1605     /* Find component to attach to */
1606     unsigned int comp_count = lig_attach.rows;
1607     if (unlikely (!comp_count)) return_trace (false);
1608 
1609     /* We must now check whether the ligature ID of the current mark glyph
1610      * is identical to the ligature ID of the found ligature.  If yes, we
1611      * can directly use the component index.  If not, we attach the mark
1612      * glyph to the last component of the ligature. */
1613     unsigned int comp_index;
1614     unsigned int lig_id = _hb_glyph_info_get_lig_id (&buffer->info[j]);
1615     unsigned int mark_id = _hb_glyph_info_get_lig_id (&buffer->cur());
1616     unsigned int mark_comp = _hb_glyph_info_get_lig_comp (&buffer->cur());
1617     if (lig_id && lig_id == mark_id && mark_comp > 0)
1618       comp_index = hb_min (comp_count, _hb_glyph_info_get_lig_comp (&buffer->cur())) - 1;
1619     else
1620       comp_index = comp_count - 1;
1621 
1622     return_trace ((this+markArray).apply (c, mark_index, comp_index, lig_attach, classCount, j));
1623   }
1624 
subsetOT::MarkLigPosFormat11625   bool subset (hb_subset_context_t *c) const
1626   {
1627     TRACE_SUBSET (this);
1628     // TODO(subset)
1629     return_trace (false);
1630   }
1631 
sanitizeOT::MarkLigPosFormat11632   bool sanitize (hb_sanitize_context_t *c) const
1633   {
1634     TRACE_SANITIZE (this);
1635     return_trace (c->check_struct (this) &&
1636 		  markCoverage.sanitize (c, this) &&
1637 		  ligatureCoverage.sanitize (c, this) &&
1638 		  markArray.sanitize (c, this) &&
1639 		  ligatureArray.sanitize (c, this, (unsigned int) classCount));
1640   }
1641 
1642   protected:
1643   HBUINT16	format;			/* Format identifier--format = 1 */
1644   OffsetTo<Coverage>
1645 		markCoverage;		/* Offset to Mark Coverage table--from
1646 					 * beginning of MarkLigPos subtable */
1647   OffsetTo<Coverage>
1648 		ligatureCoverage;	/* Offset to Ligature Coverage
1649 					 * table--from beginning of MarkLigPos
1650 					 * subtable */
1651   HBUINT16	classCount;		/* Number of defined mark classes */
1652   OffsetTo<MarkArray>
1653 		markArray;		/* Offset to MarkArray table--from
1654 					 * beginning of MarkLigPos subtable */
1655   OffsetTo<LigatureArray>
1656 		ligatureArray;		/* Offset to LigatureArray table--from
1657 					 * beginning of MarkLigPos subtable */
1658   public:
1659   DEFINE_SIZE_STATIC (12);
1660 };
1661 
1662 struct MarkLigPos
1663 {
1664   template <typename context_t, typename ...Ts>
dispatchOT::MarkLigPos1665   typename context_t::return_t dispatch (context_t *c, Ts&&... ds) const
1666   {
1667     TRACE_DISPATCH (this, u.format);
1668     if (unlikely (!c->may_dispatch (this, &u.format))) return_trace (c->no_dispatch_return_value ());
1669     switch (u.format) {
1670     case 1: return_trace (c->dispatch (u.format1, hb_forward<Ts> (ds)...));
1671     default:return_trace (c->default_return_value ());
1672     }
1673   }
1674 
1675   protected:
1676   union {
1677   HBUINT16		format;		/* Format identifier */
1678   MarkLigPosFormat1	format1;
1679   } u;
1680 };
1681 
1682 
1683 typedef AnchorMatrix Mark2Array;	/* mark2-major--
1684 					 * in order of Mark2Coverage Index--,
1685 					 * mark1-minor--
1686 					 * ordered by class--zero-based. */
1687 
1688 struct MarkMarkPosFormat1
1689 {
intersectsOT::MarkMarkPosFormat11690   bool intersects (const hb_set_t *glyphs) const
1691   { return (this+mark1Coverage).intersects (glyphs) &&
1692 	   (this+mark2Coverage).intersects (glyphs); }
1693 
collect_glyphsOT::MarkMarkPosFormat11694   void collect_glyphs (hb_collect_glyphs_context_t *c) const
1695   {
1696     if (unlikely (!(this+mark1Coverage).add_coverage (c->input))) return;
1697     if (unlikely (!(this+mark2Coverage).add_coverage (c->input))) return;
1698   }
1699 
get_coverageOT::MarkMarkPosFormat11700   const Coverage &get_coverage () const { return this+mark1Coverage; }
1701 
applyOT::MarkMarkPosFormat11702   bool apply (hb_ot_apply_context_t *c) const
1703   {
1704     TRACE_APPLY (this);
1705     hb_buffer_t *buffer = c->buffer;
1706     unsigned int mark1_index = (this+mark1Coverage).get_coverage  (buffer->cur().codepoint);
1707     if (likely (mark1_index == NOT_COVERED)) return_trace (false);
1708 
1709     /* now we search backwards for a suitable mark glyph until a non-mark glyph */
1710     hb_ot_apply_context_t::skipping_iterator_t &skippy_iter = c->iter_input;
1711     skippy_iter.reset (buffer->idx, 1);
1712     skippy_iter.set_lookup_props (c->lookup_props & ~LookupFlag::IgnoreFlags);
1713     if (!skippy_iter.prev ()) return_trace (false);
1714 
1715     if (!_hb_glyph_info_is_mark (&buffer->info[skippy_iter.idx])) { return_trace (false); }
1716 
1717     unsigned int j = skippy_iter.idx;
1718 
1719     unsigned int id1 = _hb_glyph_info_get_lig_id (&buffer->cur());
1720     unsigned int id2 = _hb_glyph_info_get_lig_id (&buffer->info[j]);
1721     unsigned int comp1 = _hb_glyph_info_get_lig_comp (&buffer->cur());
1722     unsigned int comp2 = _hb_glyph_info_get_lig_comp (&buffer->info[j]);
1723 
1724     if (likely (id1 == id2)) {
1725       if (id1 == 0) /* Marks belonging to the same base. */
1726 	goto good;
1727       else if (comp1 == comp2) /* Marks belonging to the same ligature component. */
1728 	goto good;
1729     } else {
1730       /* If ligature ids don't match, it may be the case that one of the marks
1731        * itself is a ligature.  In which case match. */
1732       if ((id1 > 0 && !comp1) || (id2 > 0 && !comp2))
1733 	goto good;
1734     }
1735 
1736     /* Didn't match. */
1737     return_trace (false);
1738 
1739     good:
1740     unsigned int mark2_index = (this+mark2Coverage).get_coverage  (buffer->info[j].codepoint);
1741     if (mark2_index == NOT_COVERED) return_trace (false);
1742 
1743     return_trace ((this+mark1Array).apply (c, mark1_index, mark2_index, this+mark2Array, classCount, j));
1744   }
1745 
subsetOT::MarkMarkPosFormat11746   bool subset (hb_subset_context_t *c) const
1747   {
1748     TRACE_SUBSET (this);
1749     // TODO(subset)
1750     return_trace (false);
1751   }
1752 
sanitizeOT::MarkMarkPosFormat11753   bool sanitize (hb_sanitize_context_t *c) const
1754   {
1755     TRACE_SANITIZE (this);
1756     return_trace (c->check_struct (this) &&
1757 		  mark1Coverage.sanitize (c, this) &&
1758 		  mark2Coverage.sanitize (c, this) &&
1759 		  mark1Array.sanitize (c, this) &&
1760 		  mark2Array.sanitize (c, this, (unsigned int) classCount));
1761   }
1762 
1763   protected:
1764   HBUINT16	format;			/* Format identifier--format = 1 */
1765   OffsetTo<Coverage>
1766 		mark1Coverage;		/* Offset to Combining Mark1 Coverage
1767 					 * table--from beginning of MarkMarkPos
1768 					 * subtable */
1769   OffsetTo<Coverage>
1770 		mark2Coverage;		/* Offset to Combining Mark2 Coverage
1771 					 * table--from beginning of MarkMarkPos
1772 					 * subtable */
1773   HBUINT16	classCount;		/* Number of defined mark classes */
1774   OffsetTo<MarkArray>
1775 		mark1Array;		/* Offset to Mark1Array table--from
1776 					 * beginning of MarkMarkPos subtable */
1777   OffsetTo<Mark2Array>
1778 		mark2Array;		/* Offset to Mark2Array table--from
1779 					 * beginning of MarkMarkPos subtable */
1780   public:
1781   DEFINE_SIZE_STATIC (12);
1782 };
1783 
1784 struct MarkMarkPos
1785 {
1786   template <typename context_t, typename ...Ts>
dispatchOT::MarkMarkPos1787   typename context_t::return_t dispatch (context_t *c, Ts&&... ds) const
1788   {
1789     TRACE_DISPATCH (this, u.format);
1790     if (unlikely (!c->may_dispatch (this, &u.format))) return_trace (c->no_dispatch_return_value ());
1791     switch (u.format) {
1792     case 1: return_trace (c->dispatch (u.format1, hb_forward<Ts> (ds)...));
1793     default:return_trace (c->default_return_value ());
1794     }
1795   }
1796 
1797   protected:
1798   union {
1799   HBUINT16		format;		/* Format identifier */
1800   MarkMarkPosFormat1	format1;
1801   } u;
1802 };
1803 
1804 
1805 struct ContextPos : Context {};
1806 
1807 struct ChainContextPos : ChainContext {};
1808 
1809 struct ExtensionPos : Extension<ExtensionPos>
1810 {
1811   typedef struct PosLookupSubTable SubTable;
1812 };
1813 
1814 
1815 
1816 /*
1817  * PosLookup
1818  */
1819 
1820 
1821 struct PosLookupSubTable
1822 {
1823   friend struct Lookup;
1824   friend struct PosLookup;
1825 
1826   enum Type {
1827     Single		= 1,
1828     Pair		= 2,
1829     Cursive		= 3,
1830     MarkBase		= 4,
1831     MarkLig		= 5,
1832     MarkMark		= 6,
1833     Context		= 7,
1834     ChainContext	= 8,
1835     Extension		= 9
1836   };
1837 
1838   template <typename context_t, typename ...Ts>
dispatchOT::PosLookupSubTable1839   typename context_t::return_t dispatch (context_t *c, unsigned int lookup_type, Ts&&... ds) const
1840   {
1841     TRACE_DISPATCH (this, lookup_type);
1842     switch (lookup_type) {
1843     case Single:		return_trace (u.single.dispatch (c, hb_forward<Ts> (ds)...));
1844     case Pair:			return_trace (u.pair.dispatch (c, hb_forward<Ts> (ds)...));
1845     case Cursive:		return_trace (u.cursive.dispatch (c, hb_forward<Ts> (ds)...));
1846     case MarkBase:		return_trace (u.markBase.dispatch (c, hb_forward<Ts> (ds)...));
1847     case MarkLig:		return_trace (u.markLig.dispatch (c, hb_forward<Ts> (ds)...));
1848     case MarkMark:		return_trace (u.markMark.dispatch (c, hb_forward<Ts> (ds)...));
1849     case Context:		return_trace (u.context.dispatch (c, hb_forward<Ts> (ds)...));
1850     case ChainContext:		return_trace (u.chainContext.dispatch (c, hb_forward<Ts> (ds)...));
1851     case Extension:		return_trace (u.extension.dispatch (c, hb_forward<Ts> (ds)...));
1852     default:			return_trace (c->default_return_value ());
1853     }
1854   }
1855 
1856   protected:
1857   union {
1858   SinglePos		single;
1859   PairPos		pair;
1860   CursivePos		cursive;
1861   MarkBasePos		markBase;
1862   MarkLigPos		markLig;
1863   MarkMarkPos		markMark;
1864   ContextPos		context;
1865   ChainContextPos	chainContext;
1866   ExtensionPos		extension;
1867   } u;
1868   public:
1869   DEFINE_SIZE_MIN (0);
1870 };
1871 
1872 
1873 struct PosLookup : Lookup
1874 {
1875   typedef struct PosLookupSubTable SubTable;
1876 
get_subtableOT::PosLookup1877   const SubTable& get_subtable (unsigned int i) const
1878   { return Lookup::get_subtable<SubTable> (i); }
1879 
is_reverseOT::PosLookup1880   bool is_reverse () const
1881   {
1882     return false;
1883   }
1884 
applyOT::PosLookup1885   bool apply (hb_ot_apply_context_t *c) const
1886   {
1887     TRACE_APPLY (this);
1888     return_trace (dispatch (c));
1889   }
1890 
intersectsOT::PosLookup1891   bool intersects (const hb_set_t *glyphs) const
1892   {
1893     hb_intersects_context_t c (glyphs);
1894     return dispatch (&c);
1895   }
1896 
collect_glyphsOT::PosLookup1897   hb_collect_glyphs_context_t::return_t collect_glyphs (hb_collect_glyphs_context_t *c) const
1898   { return dispatch (c); }
1899 
1900   template <typename set_t>
add_coverageOT::PosLookup1901   void add_coverage (set_t *glyphs) const
1902   {
1903     hb_add_coverage_context_t<set_t> c (glyphs);
1904     dispatch (&c);
1905   }
1906 
1907   HB_INTERNAL static bool apply_recurse_func (hb_ot_apply_context_t *c, unsigned int lookup_index);
1908 
1909   template <typename context_t>
1910   static typename context_t::return_t dispatch_recurse_func (context_t *c, unsigned int lookup_index);
1911 
1912   template <typename context_t, typename ...Ts>
dispatchOT::PosLookup1913   typename context_t::return_t dispatch (context_t *c, Ts&&... ds) const
1914   { return Lookup::dispatch<SubTable> (c, hb_forward<Ts> (ds)...); }
1915 
subsetOT::PosLookup1916   bool subset (hb_subset_context_t *c) const
1917   { return Lookup::subset<SubTable> (c); }
1918 
sanitizeOT::PosLookup1919   bool sanitize (hb_sanitize_context_t *c) const
1920   { return Lookup::sanitize<SubTable> (c); }
1921 };
1922 
1923 /*
1924  * GPOS -- Glyph Positioning
1925  * https://docs.microsoft.com/en-us/typography/opentype/spec/gpos
1926  */
1927 
1928 struct GPOS : GSUBGPOS
1929 {
1930   static constexpr hb_tag_t tableTag = HB_OT_TAG_GPOS;
1931 
get_lookupOT::GPOS1932   const PosLookup& get_lookup (unsigned int i) const
1933   { return CastR<PosLookup> (GSUBGPOS::get_lookup (i)); }
1934 
1935   static inline void position_start (hb_font_t *font, hb_buffer_t *buffer);
1936   static inline void position_finish_advances (hb_font_t *font, hb_buffer_t *buffer);
1937   static inline void position_finish_offsets (hb_font_t *font, hb_buffer_t *buffer);
1938 
subsetOT::GPOS1939   bool subset (hb_subset_context_t *c) const
1940   { return GSUBGPOS::subset<PosLookup> (c); }
1941 
sanitizeOT::GPOS1942   bool sanitize (hb_sanitize_context_t *c) const
1943   { return GSUBGPOS::sanitize<PosLookup> (c); }
1944 
1945   HB_INTERNAL bool is_blacklisted (hb_blob_t *blob,
1946 				   hb_face_t *face) const;
1947 
1948   typedef GSUBGPOS::accelerator_t<GPOS> accelerator_t;
1949 };
1950 
1951 
1952 static void
reverse_cursive_minor_offset(hb_glyph_position_t * pos,unsigned int i,hb_direction_t direction,unsigned int new_parent)1953 reverse_cursive_minor_offset (hb_glyph_position_t *pos, unsigned int i, hb_direction_t direction, unsigned int new_parent)
1954 {
1955   int chain = pos[i].attach_chain(), type = pos[i].attach_type();
1956   if (likely (!chain || 0 == (type & ATTACH_TYPE_CURSIVE)))
1957     return;
1958 
1959   pos[i].attach_chain() = 0;
1960 
1961   unsigned int j = (int) i + chain;
1962 
1963   /* Stop if we see new parent in the chain. */
1964   if (j == new_parent)
1965     return;
1966 
1967   reverse_cursive_minor_offset (pos, j, direction, new_parent);
1968 
1969   if (HB_DIRECTION_IS_HORIZONTAL (direction))
1970     pos[j].y_offset = -pos[i].y_offset;
1971   else
1972     pos[j].x_offset = -pos[i].x_offset;
1973 
1974   pos[j].attach_chain() = -chain;
1975   pos[j].attach_type() = type;
1976 }
1977 static void
propagate_attachment_offsets(hb_glyph_position_t * pos,unsigned int len,unsigned int i,hb_direction_t direction)1978 propagate_attachment_offsets (hb_glyph_position_t *pos,
1979 			      unsigned int len,
1980 			      unsigned int i,
1981 			      hb_direction_t direction)
1982 {
1983   /* Adjusts offsets of attached glyphs (both cursive and mark) to accumulate
1984    * offset of glyph they are attached to. */
1985   int chain = pos[i].attach_chain(), type = pos[i].attach_type();
1986   if (likely (!chain))
1987     return;
1988 
1989   pos[i].attach_chain() = 0;
1990 
1991   unsigned int j = (int) i + chain;
1992 
1993   if (unlikely (j >= len))
1994     return;
1995 
1996   propagate_attachment_offsets (pos, len, j, direction);
1997 
1998   assert (!!(type & ATTACH_TYPE_MARK) ^ !!(type & ATTACH_TYPE_CURSIVE));
1999 
2000   if (type & ATTACH_TYPE_CURSIVE)
2001   {
2002     if (HB_DIRECTION_IS_HORIZONTAL (direction))
2003       pos[i].y_offset += pos[j].y_offset;
2004     else
2005       pos[i].x_offset += pos[j].x_offset;
2006   }
2007   else /*if (type & ATTACH_TYPE_MARK)*/
2008   {
2009     pos[i].x_offset += pos[j].x_offset;
2010     pos[i].y_offset += pos[j].y_offset;
2011 
2012     assert (j < i);
2013     if (HB_DIRECTION_IS_FORWARD (direction))
2014       for (unsigned int k = j; k < i; k++) {
2015 	pos[i].x_offset -= pos[k].x_advance;
2016 	pos[i].y_offset -= pos[k].y_advance;
2017       }
2018     else
2019       for (unsigned int k = j + 1; k < i + 1; k++) {
2020 	pos[i].x_offset += pos[k].x_advance;
2021 	pos[i].y_offset += pos[k].y_advance;
2022       }
2023   }
2024 }
2025 
2026 void
position_start(hb_font_t * font HB_UNUSED,hb_buffer_t * buffer)2027 GPOS::position_start (hb_font_t *font HB_UNUSED, hb_buffer_t *buffer)
2028 {
2029   unsigned int count = buffer->len;
2030   for (unsigned int i = 0; i < count; i++)
2031     buffer->pos[i].attach_chain() = buffer->pos[i].attach_type() = 0;
2032 }
2033 
2034 void
position_finish_advances(hb_font_t * font HB_UNUSED,hb_buffer_t * buffer HB_UNUSED)2035 GPOS::position_finish_advances (hb_font_t *font HB_UNUSED, hb_buffer_t *buffer HB_UNUSED)
2036 {
2037   //_hb_buffer_assert_gsubgpos_vars (buffer);
2038 }
2039 
2040 void
position_finish_offsets(hb_font_t * font HB_UNUSED,hb_buffer_t * buffer)2041 GPOS::position_finish_offsets (hb_font_t *font HB_UNUSED, hb_buffer_t *buffer)
2042 {
2043   _hb_buffer_assert_gsubgpos_vars (buffer);
2044 
2045   unsigned int len;
2046   hb_glyph_position_t *pos = hb_buffer_get_glyph_positions (buffer, &len);
2047   hb_direction_t direction = buffer->props.direction;
2048 
2049   /* Handle attachments */
2050   if (buffer->scratch_flags & HB_BUFFER_SCRATCH_FLAG_HAS_GPOS_ATTACHMENT)
2051     for (unsigned int i = 0; i < len; i++)
2052       propagate_attachment_offsets (pos, len, i, direction);
2053 }
2054 
2055 
2056 struct GPOS_accelerator_t : GPOS::accelerator_t {};
2057 
2058 
2059 /* Out-of-class implementation for methods recursing */
2060 
2061 #ifndef HB_NO_OT_LAYOUT
2062 template <typename context_t>
dispatch_recurse_func(context_t * c,unsigned int lookup_index)2063 /*static*/ inline typename context_t::return_t PosLookup::dispatch_recurse_func (context_t *c, unsigned int lookup_index)
2064 {
2065   const PosLookup &l = c->face->table.GPOS.get_relaxed ()->table->get_lookup (lookup_index);
2066   return l.dispatch (c);
2067 }
apply_recurse_func(hb_ot_apply_context_t * c,unsigned int lookup_index)2068 /*static*/ inline bool PosLookup::apply_recurse_func (hb_ot_apply_context_t *c, unsigned int lookup_index)
2069 {
2070   const PosLookup &l = c->face->table.GPOS.get_relaxed ()->table->get_lookup (lookup_index);
2071   unsigned int saved_lookup_props = c->lookup_props;
2072   unsigned int saved_lookup_index = c->lookup_index;
2073   c->set_lookup_index (lookup_index);
2074   c->set_lookup_props (l.get_props ());
2075   bool ret = l.dispatch (c);
2076   c->set_lookup_index (saved_lookup_index);
2077   c->set_lookup_props (saved_lookup_props);
2078   return ret;
2079 }
2080 #endif
2081 
2082 
2083 } /* namespace OT */
2084 
2085 
2086 #endif /* HB_OT_LAYOUT_GPOS_TABLE_HH */
2087