xref: /aosp_15_r20/external/harfbuzz_ng/src/hb-coretext-shape.cc (revision 2d1272b857b1f7575e6e246373e1cb218663db8a)
1 /*
2  * Copyright © 2012,2013  Mozilla Foundation.
3  * Copyright © 2012,2013  Google, Inc.
4  *
5  *  This is part of HarfBuzz, a text shaping library.
6  *
7  * Permission is hereby granted, without written agreement and without
8  * license or royalty fees, to use, copy, modify, and distribute this
9  * software and its documentation for any purpose, provided that the
10  * above copyright notice and the following two paragraphs appear in
11  * all copies of this software.
12  *
13  * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
14  * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
15  * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
16  * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
17  * DAMAGE.
18  *
19  * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
20  * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
21  * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
22  * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
23  * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
24  *
25  * Mozilla Author(s): Jonathan Kew
26  * Google Author(s): Behdad Esfahbod
27  */
28 
29 #include "hb.hh"
30 
31 #ifdef HAVE_CORETEXT
32 
33 #include "hb-shaper-impl.hh"
34 
35 #include "hb-coretext.h"
36 #include "hb-aat-layout.hh"
37 
38 
39 /**
40  * SECTION:hb-coretext
41  * @title: hb-coretext
42  * @short_description: CoreText integration
43  * @include: hb-coretext.h
44  *
45  * Functions for using HarfBuzz with the CoreText fonts.
46  **/
47 
48 /* https://developer.apple.com/documentation/coretext/1508745-ctfontcreatewithgraphicsfont */
49 #define HB_CORETEXT_DEFAULT_FONT_SIZE 12.f
50 
51 static CTFontRef create_ct_font (CGFontRef cg_font, CGFloat font_size);
52 
53 static void
release_table_data(void * user_data)54 release_table_data (void *user_data)
55 {
56   CFDataRef cf_data = reinterpret_cast<CFDataRef> (user_data);
57   CFRelease(cf_data);
58 }
59 
60 static hb_blob_t *
_hb_cg_reference_table(hb_face_t * face HB_UNUSED,hb_tag_t tag,void * user_data)61 _hb_cg_reference_table (hb_face_t *face HB_UNUSED, hb_tag_t tag, void *user_data)
62 {
63   CGFontRef cg_font = reinterpret_cast<CGFontRef> (user_data);
64   CFDataRef cf_data = CGFontCopyTableForTag (cg_font, tag);
65   if (unlikely (!cf_data))
66     return nullptr;
67 
68   const char *data = reinterpret_cast<const char*> (CFDataGetBytePtr (cf_data));
69   const size_t length = CFDataGetLength (cf_data);
70   if (!data || !length)
71   {
72     CFRelease (cf_data);
73     return nullptr;
74   }
75 
76   return hb_blob_create (data, length, HB_MEMORY_MODE_READONLY,
77 			 reinterpret_cast<void *> (const_cast<__CFData *> (cf_data)),
78 			 release_table_data);
79 }
80 
81 static unsigned
_hb_cg_get_table_tags(const hb_face_t * face HB_UNUSED,unsigned int start_offset,unsigned int * table_count,hb_tag_t * table_tags,void * user_data)82 _hb_cg_get_table_tags (const hb_face_t *face HB_UNUSED,
83 		       unsigned int start_offset,
84 		       unsigned int *table_count,
85 		       hb_tag_t *table_tags,
86 		       void *user_data)
87 {
88   CGFontRef cg_font = reinterpret_cast<CGFontRef> (user_data);
89 
90   CTFontRef ct_font = create_ct_font (cg_font, (CGFloat) HB_CORETEXT_DEFAULT_FONT_SIZE);
91 
92   auto arr = CTFontCopyAvailableTables (ct_font, kCTFontTableOptionNoOptions);
93 
94   unsigned population = (unsigned) CFArrayGetCount (arr);
95   unsigned end_offset;
96 
97   if (!table_count)
98     goto done;
99 
100   if (unlikely (start_offset >= population))
101   {
102     *table_count = 0;
103     goto done;
104   }
105 
106   end_offset = start_offset + *table_count;
107   if (unlikely (end_offset < start_offset))
108   {
109     *table_count = 0;
110     goto done;
111   }
112   end_offset= hb_min (end_offset, (unsigned) population);
113 
114   *table_count = end_offset - start_offset;
115   for (unsigned i = start_offset; i < end_offset; i++)
116   {
117     CTFontTableTag tag = (CTFontTableTag)(uintptr_t) CFArrayGetValueAtIndex (arr, i);
118     table_tags[i - start_offset] = tag;
119   }
120 
121 done:
122   CFRelease (arr);
123   CFRelease (ct_font);
124   return population;
125 }
126 
127 static void
_hb_cg_font_release(void * data)128 _hb_cg_font_release (void *data)
129 {
130   CGFontRelease ((CGFontRef) data);
131 }
132 
133 
134 static CTFontDescriptorRef
get_last_resort_font_desc()135 get_last_resort_font_desc ()
136 {
137   // TODO Handle allocation failures?
138   CTFontDescriptorRef last_resort = CTFontDescriptorCreateWithNameAndSize (CFSTR("LastResort"), 0);
139   CFArrayRef cascade_list = CFArrayCreate (kCFAllocatorDefault,
140 					   (const void **) &last_resort,
141 					   1,
142 					   &kCFTypeArrayCallBacks);
143   CFRelease (last_resort);
144   CFDictionaryRef attributes = CFDictionaryCreate (kCFAllocatorDefault,
145 						   (const void **) &kCTFontCascadeListAttribute,
146 						   (const void **) &cascade_list,
147 						   1,
148 						   &kCFTypeDictionaryKeyCallBacks,
149 						   &kCFTypeDictionaryValueCallBacks);
150   CFRelease (cascade_list);
151 
152   CTFontDescriptorRef font_desc = CTFontDescriptorCreateWithAttributes (attributes);
153   CFRelease (attributes);
154   return font_desc;
155 }
156 
157 static void
release_data(void * info,const void * data,size_t size)158 release_data (void *info, const void *data, size_t size)
159 {
160   assert (hb_blob_get_length ((hb_blob_t *) info) == size &&
161 	  hb_blob_get_data ((hb_blob_t *) info, nullptr) == data);
162 
163   hb_blob_destroy ((hb_blob_t *) info);
164 }
165 
166 static CGFontRef
create_cg_font(hb_face_t * face)167 create_cg_font (hb_face_t *face)
168 {
169   CGFontRef cg_font = nullptr;
170   if (face->destroy == _hb_cg_font_release)
171   {
172     cg_font = CGFontRetain ((CGFontRef) face->user_data);
173   }
174   else
175   {
176     hb_blob_t *blob = hb_face_reference_blob (face);
177     unsigned int blob_length;
178     const char *blob_data = hb_blob_get_data (blob, &blob_length);
179     if (unlikely (!blob_length))
180       DEBUG_MSG (CORETEXT, face, "Face has empty blob");
181 
182     CGDataProviderRef provider = CGDataProviderCreateWithData (blob, blob_data, blob_length, &release_data);
183     if (likely (provider))
184     {
185       cg_font = CGFontCreateWithDataProvider (provider);
186       if (unlikely (!cg_font))
187 	DEBUG_MSG (CORETEXT, face, "Face CGFontCreateWithDataProvider() failed");
188       CGDataProviderRelease (provider);
189     }
190   }
191   return cg_font;
192 }
193 
194 static CTFontRef
create_ct_font(CGFontRef cg_font,CGFloat font_size)195 create_ct_font (CGFontRef cg_font, CGFloat font_size)
196 {
197   CTFontRef ct_font = nullptr;
198 
199   /* CoreText does not enable trak table usage / tracking when creating a CTFont
200    * using CTFontCreateWithGraphicsFont. The only way of enabling tracking seems
201    * to be through the CTFontCreateUIFontForLanguage call. */
202   CFStringRef cg_postscript_name = CGFontCopyPostScriptName (cg_font);
203   if (CFStringHasPrefix (cg_postscript_name, CFSTR (".SFNSText")) ||
204       CFStringHasPrefix (cg_postscript_name, CFSTR (".SFNSDisplay")))
205   {
206 #if !(defined(TARGET_OS_IPHONE) && TARGET_OS_IPHONE) && MAC_OS_X_VERSION_MIN_REQUIRED < 1080
207 # define kCTFontUIFontSystem kCTFontSystemFontType
208 # define kCTFontUIFontEmphasizedSystem kCTFontEmphasizedSystemFontType
209 #endif
210     CTFontUIFontType font_type = kCTFontUIFontSystem;
211     if (CFStringHasSuffix (cg_postscript_name, CFSTR ("-Bold")))
212       font_type = kCTFontUIFontEmphasizedSystem;
213 
214     ct_font = CTFontCreateUIFontForLanguage (font_type, font_size, nullptr);
215     CFStringRef ct_result_name = CTFontCopyPostScriptName(ct_font);
216     if (CFStringCompare (ct_result_name, cg_postscript_name, 0) != kCFCompareEqualTo)
217     {
218       CFRelease(ct_font);
219       ct_font = nullptr;
220     }
221     CFRelease (ct_result_name);
222   }
223   CFRelease (cg_postscript_name);
224 
225   if (!ct_font)
226     ct_font = CTFontCreateWithGraphicsFont (cg_font, font_size, nullptr, nullptr);
227 
228   if (unlikely (!ct_font)) {
229     DEBUG_MSG (CORETEXT, cg_font, "Font CTFontCreateWithGraphicsFont() failed");
230     return nullptr;
231   }
232 
233   /* crbug.com/576941 and crbug.com/625902 and the investigation in the latter
234    * bug indicate that the cascade list reconfiguration occasionally causes
235    * crashes in CoreText on OS X 10.9, thus let's skip this step on older
236    * operating system versions. Except for the emoji font, where _not_
237    * reconfiguring the cascade list causes CoreText crashes. For details, see
238    * crbug.com/549610 */
239   // 0x00070000 stands for "kCTVersionNumber10_10", see CoreText.h
240 #pragma GCC diagnostic push
241 #pragma GCC diagnostic ignored "-Wdeprecated-declarations"
242   if (&CTGetCoreTextVersion != nullptr && CTGetCoreTextVersion() < 0x00070000) {
243 #pragma GCC diagnostic pop
244     CFStringRef fontName = CTFontCopyPostScriptName (ct_font);
245     bool isEmojiFont = CFStringCompare (fontName, CFSTR("AppleColorEmoji"), 0) == kCFCompareEqualTo;
246     CFRelease (fontName);
247     if (!isEmojiFont)
248       return ct_font;
249   }
250 
251   CFURLRef original_url = nullptr;
252 #if !(defined(TARGET_OS_IPHONE) && TARGET_OS_IPHONE) && MAC_OS_X_VERSION_MIN_REQUIRED < 1060
253   ATSFontRef atsFont;
254   FSRef fsref;
255   OSStatus status;
256   atsFont = CTFontGetPlatformFont (ct_font, NULL);
257   status = ATSFontGetFileReference (atsFont, &fsref);
258   if (status == noErr)
259     original_url = CFURLCreateFromFSRef (NULL, &fsref);
260 #else
261   original_url = (CFURLRef) CTFontCopyAttribute (ct_font, kCTFontURLAttribute);
262 #endif
263 
264   /* Create font copy with cascade list that has LastResort first; this speeds up CoreText
265    * font fallback which we don't need anyway. */
266   {
267     CTFontDescriptorRef last_resort_font_desc = get_last_resort_font_desc ();
268     CTFontRef new_ct_font = CTFontCreateCopyWithAttributes (ct_font, 0.0, nullptr, last_resort_font_desc);
269     CFRelease (last_resort_font_desc);
270     if (new_ct_font)
271     {
272       /* The CTFontCreateCopyWithAttributes call fails to stay on the same font
273        * when reconfiguring the cascade list and may switch to a different font
274        * when there are fonts that go by the same name, since the descriptor is
275        * just name and size.
276        *
277        * Avoid reconfiguring the cascade lists if the new font is outside the
278        * system locations that we cannot access from the sandboxed renderer
279        * process in Blink. This can be detected by the new file URL location
280        * that the newly found font points to. */
281       CFURLRef new_url = nullptr;
282 #if !(defined(TARGET_OS_IPHONE) && TARGET_OS_IPHONE) && MAC_OS_X_VERSION_MIN_REQUIRED < 1060
283       atsFont = CTFontGetPlatformFont (new_ct_font, NULL);
284       status = ATSFontGetFileReference (atsFont, &fsref);
285       if (status == noErr)
286 	new_url = CFURLCreateFromFSRef (NULL, &fsref);
287 #else
288       new_url = (CFURLRef) CTFontCopyAttribute (new_ct_font, kCTFontURLAttribute);
289 #endif
290       // Keep reconfigured font if URL cannot be retrieved (seems to be the case
291       // on Mac OS 10.12 Sierra), speculative fix for crbug.com/625606
292       if (!original_url || !new_url || CFEqual (original_url, new_url)) {
293 	CFRelease (ct_font);
294 	ct_font = new_ct_font;
295       } else {
296 	CFRelease (new_ct_font);
297 	DEBUG_MSG (CORETEXT, ct_font, "Discarding reconfigured CTFont, location changed.");
298       }
299       if (new_url)
300 	CFRelease (new_url);
301     }
302     else
303       DEBUG_MSG (CORETEXT, ct_font, "Font copy with empty cascade list failed");
304   }
305 
306   if (original_url)
307     CFRelease (original_url);
308   return ct_font;
309 }
310 
311 hb_coretext_face_data_t *
_hb_coretext_shaper_face_data_create(hb_face_t * face)312 _hb_coretext_shaper_face_data_create (hb_face_t *face)
313 {
314   CGFontRef cg_font = create_cg_font (face);
315 
316   if (unlikely (!cg_font))
317   {
318     DEBUG_MSG (CORETEXT, face, "CGFont creation failed..");
319     return nullptr;
320   }
321 
322   return (hb_coretext_face_data_t *) cg_font;
323 }
324 
325 void
_hb_coretext_shaper_face_data_destroy(hb_coretext_face_data_t * data)326 _hb_coretext_shaper_face_data_destroy (hb_coretext_face_data_t *data)
327 {
328   CFRelease ((CGFontRef) data);
329 }
330 
331 /**
332  * hb_coretext_face_create:
333  * @cg_font: The CGFontRef to work upon
334  *
335  * Creates an #hb_face_t face object from the specified
336  * CGFontRef.
337  *
338  * Return value: (transfer full): The new face object
339  *
340  * Since: 0.9.10
341  */
342 hb_face_t *
hb_coretext_face_create(CGFontRef cg_font)343 hb_coretext_face_create (CGFontRef cg_font)
344 {
345   hb_face_t *face = hb_face_create_for_tables (_hb_cg_reference_table, CGFontRetain (cg_font), _hb_cg_font_release);
346   hb_face_set_get_table_tags_func (face, _hb_cg_get_table_tags, cg_font, nullptr);
347   return face;
348 }
349 
350 /**
351  * hb_coretext_face_create_from_file_or_fail:
352  * @file_name: A font filename
353  * @index: The index of the face within the file
354  *
355  * Creates an #hb_face_t face object from the specified
356  * font file and face index.
357  *
358  * This is similar in functionality to hb_face_create_from_file_or_fail(),
359  * but uses the CoreText library for loading the font file.
360  *
361  * Return value: (transfer full): The new face object, or `NULL` if
362  * no face is found at the specified index or the file cannot be read.
363  *
364  * Since: 10.1.0
365  */
366 hb_face_t *
hb_coretext_face_create_from_file_or_fail(const char * file_name,unsigned int index)367 hb_coretext_face_create_from_file_or_fail (const char   *file_name,
368 					   unsigned int  index)
369 {
370   auto url = CFURLCreateFromFileSystemRepresentation (nullptr,
371 						      (const UInt8 *) file_name,
372 						      strlen (file_name),
373 						      false);
374   if (unlikely (!url))
375     return nullptr;
376 
377   auto ct_font_desc_array = CTFontManagerCreateFontDescriptorsFromURL (url);
378   if (unlikely (!ct_font_desc_array))
379   {
380     CFRelease (url);
381     return nullptr;
382   }
383   auto ct_font_desc = (CFArrayGetCount (ct_font_desc_array) > index) ?
384 		      (CTFontDescriptorRef) CFArrayGetValueAtIndex (ct_font_desc_array, index) : nullptr;
385   if (unlikely (!ct_font_desc))
386   {
387 	  CFRelease (ct_font_desc_array);
388 	  CFRelease (url);
389 	  return nullptr;
390   }
391   CFRelease (url);
392   auto ct_font = ct_font_desc ? CTFontCreateWithFontDescriptor (ct_font_desc, 0, nullptr) : nullptr;
393   CFRelease (ct_font_desc_array);
394   if (unlikely (!ct_font))
395     return nullptr;
396 
397   auto cg_font = ct_font ? CTFontCopyGraphicsFont (ct_font, nullptr) : nullptr;
398   CFRelease (ct_font);
399   if (unlikely (!cg_font))
400     return nullptr;
401 
402   hb_face_t *face = hb_coretext_face_create (cg_font);
403   if (unlikely (hb_face_is_immutable (face)))
404     return nullptr;
405 
406   return face;
407 }
408 
409 /**
410  * hb_coretext_face_get_cg_font:
411  * @face: The #hb_face_t to work upon
412  *
413  * Fetches the CGFontRef associated with an #hb_face_t
414  * face object
415  *
416  * Return value: the CGFontRef found
417  *
418  * Since: 0.9.10
419  */
420 CGFontRef
hb_coretext_face_get_cg_font(hb_face_t * face)421 hb_coretext_face_get_cg_font (hb_face_t *face)
422 {
423   return (CGFontRef) (const void *) face->data.coretext;
424 }
425 
426 
427 hb_coretext_font_data_t *
_hb_coretext_shaper_font_data_create(hb_font_t * font)428 _hb_coretext_shaper_font_data_create (hb_font_t *font)
429 {
430   hb_face_t *face = font->face;
431   const hb_coretext_face_data_t *face_data = face->data.coretext;
432   if (unlikely (!face_data)) return nullptr;
433   CGFontRef cg_font = (CGFontRef) (const void *) face->data.coretext;
434 
435   CGFloat font_size = (CGFloat) (font->ptem <= 0.f ? HB_CORETEXT_DEFAULT_FONT_SIZE : font->ptem);
436   CTFontRef ct_font = create_ct_font (cg_font, font_size);
437 
438   if (unlikely (!ct_font))
439   {
440     DEBUG_MSG (CORETEXT, font, "CGFont creation failed..");
441     return nullptr;
442   }
443 
444   if (font->num_coords)
445   {
446     CFMutableDictionaryRef variations =
447       CFDictionaryCreateMutable (kCFAllocatorDefault,
448 				 font->num_coords,
449 				 &kCFTypeDictionaryKeyCallBacks,
450 				 &kCFTypeDictionaryValueCallBacks);
451 
452     for (unsigned i = 0; i < font->num_coords; i++)
453     {
454       if (font->coords[i] == 0.) continue;
455 
456       hb_ot_var_axis_info_t info;
457       unsigned int c = 1;
458       hb_ot_var_get_axis_infos (font->face, i, &c, &info);
459       float v = hb_clamp (font->design_coords[i], info.min_value, info.max_value);
460 
461       CFNumberRef tag_number = CFNumberCreate (kCFAllocatorDefault, kCFNumberIntType, &info.tag);
462       CFNumberRef value_number = CFNumberCreate (kCFAllocatorDefault, kCFNumberFloatType, &v);
463       CFDictionarySetValue (variations, tag_number, value_number);
464       CFRelease (tag_number);
465       CFRelease (value_number);
466     }
467 
468     CFDictionaryRef attributes =
469       CFDictionaryCreate (kCFAllocatorDefault,
470 			  (const void **) &kCTFontVariationAttribute,
471 			  (const void **) &variations,
472 			  1,
473 			  &kCFTypeDictionaryKeyCallBacks,
474 			  &kCFTypeDictionaryValueCallBacks);
475 
476     CTFontDescriptorRef varDesc = CTFontDescriptorCreateWithAttributes (attributes);
477     CTFontRef new_ct_font = CTFontCreateCopyWithAttributes (ct_font, 0, nullptr, varDesc);
478 
479     CFRelease (ct_font);
480     CFRelease (attributes);
481     CFRelease (variations);
482     ct_font = new_ct_font;
483   }
484 
485   return (hb_coretext_font_data_t *) ct_font;
486 }
487 
488 void
_hb_coretext_shaper_font_data_destroy(hb_coretext_font_data_t * data)489 _hb_coretext_shaper_font_data_destroy (hb_coretext_font_data_t *data)
490 {
491   CFRelease ((CTFontRef) data);
492 }
493 
494 /**
495  * hb_coretext_font_create:
496  * @ct_font: The CTFontRef to work upon
497  *
498  * Creates an #hb_font_t font object from the specified
499  * CTFontRef.
500  *
501  * The created font uses the default font functions implemented
502  * navitely by HarfBuzz. If you want to use the CoreText font functions
503  * instead (rarely needed), you can do so by calling
504  * by hb_coretext_font_set_funcs().
505  *
506  * Return value: (transfer full): The new font object
507  *
508  * Since: 1.7.2
509  **/
510 hb_font_t *
hb_coretext_font_create(CTFontRef ct_font)511 hb_coretext_font_create (CTFontRef ct_font)
512 {
513   CGFontRef cg_font = CTFontCopyGraphicsFont (ct_font, nullptr);
514   hb_face_t *face = hb_coretext_face_create (cg_font);
515   CFRelease (cg_font);
516   hb_font_t *font = hb_font_create (face);
517   hb_face_destroy (face);
518 
519   if (unlikely (hb_object_is_immutable (font)))
520     return font;
521 
522   hb_font_set_ptem (font, CTFontGetSize (ct_font));
523 
524   /* Let there be dragons here... */
525   font->data.coretext.cmpexch (nullptr, (hb_coretext_font_data_t *) CFRetain (ct_font));
526 
527   // https://github.com/harfbuzz/harfbuzz/pull/4895#issuecomment-2408471254
528   //hb_coretext_font_set_funcs (font);
529 
530   return font;
531 }
532 
533 /**
534  * hb_coretext_font_get_ct_font:
535  * @font: #hb_font_t to work upon
536  *
537  * Fetches the CTFontRef associated with the specified
538  * #hb_font_t font object.
539  *
540  * Return value: the CTFontRef found
541  *
542  * Since: 0.9.10
543  */
544 CTFontRef
hb_coretext_font_get_ct_font(hb_font_t * font)545 hb_coretext_font_get_ct_font (hb_font_t *font)
546 {
547   CTFontRef ct_font = (CTFontRef) (const void *) font->data.coretext;
548   return ct_font ? (CTFontRef) ct_font : nullptr;
549 }
550 
551 
552 /*
553  * shaper
554  */
555 
556 struct feature_record_t {
557   unsigned int feature;
558   unsigned int setting;
559 };
560 
561 struct active_feature_t {
562   feature_record_t rec;
563   unsigned int order;
564 
cmpactive_feature_t565   HB_INTERNAL static int cmp (const void *pa, const void *pb) {
566     const active_feature_t *a = (const active_feature_t *) pa;
567     const active_feature_t *b = (const active_feature_t *) pb;
568     return a->rec.feature < b->rec.feature ? -1 : a->rec.feature > b->rec.feature ? 1 :
569 	   a->order < b->order ? -1 : a->order > b->order ? 1 :
570 	   a->rec.setting < b->rec.setting ? -1 : a->rec.setting > b->rec.setting ? 1 :
571 	   0;
572   }
operator ==active_feature_t573   bool operator== (const active_feature_t& f) const {
574     return cmp (this, &f) == 0;
575   }
576 };
577 
578 struct feature_event_t {
579   unsigned int index;
580   bool start;
581   active_feature_t feature;
582 
cmpfeature_event_t583   HB_INTERNAL static int cmp (const void *pa, const void *pb) {
584     const feature_event_t *a = (const feature_event_t *) pa;
585     const feature_event_t *b = (const feature_event_t *) pb;
586     return a->index < b->index ? -1 : a->index > b->index ? 1 :
587 	   a->start < b->start ? -1 : a->start > b->start ? 1 :
588 	   active_feature_t::cmp (&a->feature, &b->feature);
589   }
590 };
591 
592 struct range_record_t {
593   CTFontRef font;
594   unsigned int index_first; /* == start */
595   unsigned int index_last;  /* == end - 1 */
596 };
597 
598 
599 hb_bool_t
_hb_coretext_shape(hb_shape_plan_t * shape_plan,hb_font_t * font,hb_buffer_t * buffer,const hb_feature_t * features,unsigned int num_features)600 _hb_coretext_shape (hb_shape_plan_t    *shape_plan,
601 		    hb_font_t          *font,
602 		    hb_buffer_t        *buffer,
603 		    const hb_feature_t *features,
604 		    unsigned int        num_features)
605 {
606   hb_face_t *face = font->face;
607   CGFontRef cg_font = (CGFontRef) (const void *) face->data.coretext;
608   CTFontRef ct_font = (CTFontRef) (const void *) font->data.coretext;
609 
610   CGFloat ct_font_size = CTFontGetSize (ct_font);
611   CGFloat x_mult = (CGFloat) font->x_scale / ct_font_size;
612   CGFloat y_mult = (CGFloat) font->y_scale / ct_font_size;
613 
614   /* Attach marks to their bases, to match the 'ot' shaper.
615    * Adapted from a very old version of hb-ot-shape:hb_form_clusters().
616    * Note that this only makes us be closer to the 'ot' shaper,
617    * but by no means the same.  For example, if there's
618    * B1 M1 B2 M2, and B1-B2 form a ligature, M2's cluster will
619    * continue pointing to B2 even though B2 was merged into B1's
620    * cluster... */
621   if (buffer->cluster_level == HB_BUFFER_CLUSTER_LEVEL_MONOTONE_GRAPHEMES)
622   {
623     hb_unicode_funcs_t *unicode = buffer->unicode;
624     unsigned int count = buffer->len;
625     hb_glyph_info_t *info = buffer->info;
626     for (unsigned int i = 1; i < count; i++)
627       if (HB_UNICODE_GENERAL_CATEGORY_IS_MARK (unicode->general_category (info[i].codepoint)))
628 	buffer->merge_clusters (i - 1, i + 1);
629   }
630 
631   hb_vector_t<range_record_t> range_records;
632 
633   /*
634    * Set up features.
635    * (copied + modified from code from hb-uniscribe.cc)
636    */
637   if (num_features)
638   {
639     /* Sort features by start/end events. */
640     hb_vector_t<feature_event_t> feature_events;
641     for (unsigned int i = 0; i < num_features; i++)
642     {
643       active_feature_t feature;
644 
645 #if MAC_OS_X_VERSION_MIN_REQUIRED < 101000
646       const hb_aat_feature_mapping_t * mapping = hb_aat_layout_find_feature_mapping (features[i].tag);
647       if (!mapping)
648 	continue;
649 
650       feature.rec.feature = mapping->aatFeatureType;
651       feature.rec.setting = features[i].value ? mapping->selectorToEnable : mapping->selectorToDisable;
652 #else
653       feature.rec.feature = features[i].tag;
654       feature.rec.setting = features[i].value;
655 #endif
656       feature.order = i;
657 
658       feature_event_t *event;
659 
660       event = feature_events.push ();
661       event->index = features[i].start;
662       event->start = true;
663       event->feature = feature;
664 
665       event = feature_events.push ();
666       event->index = features[i].end;
667       event->start = false;
668       event->feature = feature;
669     }
670     feature_events.qsort ();
671     /* Add a strategic final event. */
672     {
673       active_feature_t feature;
674       feature.rec.feature = HB_TAG_NONE;
675       feature.rec.setting = 0;
676       feature.order = num_features + 1;
677 
678       feature_event_t *event = feature_events.push ();
679       event->index = 0; /* This value does magic. */
680       event->start = false;
681       event->feature = feature;
682     }
683 
684     /* Scan events and save features for each range. */
685     hb_vector_t<active_feature_t> active_features;
686     unsigned int last_index = 0;
687     for (unsigned int i = 0; i < feature_events.length; i++)
688     {
689       feature_event_t *event = &feature_events[i];
690 
691       if (event->index != last_index)
692       {
693 	/* Save a snapshot of active features and the range. */
694 	range_record_t *range = range_records.push ();
695 
696 	if (active_features.length)
697 	{
698 	  CFMutableArrayRef features_array = CFArrayCreateMutable(kCFAllocatorDefault, 0, &kCFTypeArrayCallBacks);
699 
700 	  /* TODO sort and resolve conflicting features? */
701 	  /* active_features.qsort (); */
702 	  for (unsigned int j = 0; j < active_features.length; j++)
703 	  {
704 #if MAC_OS_X_VERSION_MIN_REQUIRED < 101000
705 	    CFStringRef keys[] = {
706 	      kCTFontFeatureTypeIdentifierKey,
707 	      kCTFontFeatureSelectorIdentifierKey
708 	    };
709 	    CFNumberRef values[] = {
710 	      CFNumberCreate (kCFAllocatorDefault, kCFNumberIntType, &active_features[j].rec.feature),
711 	      CFNumberCreate (kCFAllocatorDefault, kCFNumberIntType, &active_features[j].rec.setting)
712 	    };
713 #else
714 	    char tag[5] = {HB_UNTAG (active_features[j].rec.feature)};
715 	    CFTypeRef keys[] = {
716 	      kCTFontOpenTypeFeatureTag,
717 	      kCTFontOpenTypeFeatureValue
718 	    };
719 	    CFTypeRef values[] = {
720 	      CFStringCreateWithCString (kCFAllocatorDefault, tag, kCFStringEncodingASCII),
721 	      CFNumberCreate (kCFAllocatorDefault, kCFNumberIntType, &active_features[j].rec.setting)
722 	    };
723 #endif
724 	    static_assert ((ARRAY_LENGTH_CONST (keys) == ARRAY_LENGTH_CONST (values)), "");
725 	    CFDictionaryRef dict = CFDictionaryCreate (kCFAllocatorDefault,
726 						       (const void **) keys,
727 						       (const void **) values,
728 						       ARRAY_LENGTH (keys),
729 						       &kCFTypeDictionaryKeyCallBacks,
730 						       &kCFTypeDictionaryValueCallBacks);
731 	    for (unsigned int i = 0; i < ARRAY_LENGTH (values); i++)
732 	      CFRelease (values[i]);
733 
734 	    CFArrayAppendValue (features_array, dict);
735 	    CFRelease (dict);
736 
737 	  }
738 
739 	  CFDictionaryRef attributes = CFDictionaryCreate (kCFAllocatorDefault,
740 							   (const void **) &kCTFontFeatureSettingsAttribute,
741 							   (const void **) &features_array,
742 							   1,
743 							   &kCFTypeDictionaryKeyCallBacks,
744 							   &kCFTypeDictionaryValueCallBacks);
745 	  CFRelease (features_array);
746 
747 	  CTFontDescriptorRef font_desc = CTFontDescriptorCreateWithAttributes (attributes);
748 	  CFRelease (attributes);
749 
750 	  range->font = CTFontCreateCopyWithAttributes (ct_font, 0.0, nullptr, font_desc);
751 	  CFRelease (font_desc);
752 	}
753 	else
754 	{
755 	  range->font = nullptr;
756 	}
757 
758 	range->index_first = last_index;
759 	range->index_last  = event->index - 1;
760 
761 	last_index = event->index;
762       }
763 
764       if (event->start)
765       {
766 	active_features.push (event->feature);
767       } else {
768 	active_feature_t *feature = active_features.lsearch (event->feature);
769 	if (feature)
770 	  active_features.remove_ordered (feature - active_features.arrayZ);
771       }
772     }
773   }
774 
775   unsigned int scratch_size;
776   hb_buffer_t::scratch_buffer_t *scratch = buffer->get_scratch_buffer (&scratch_size);
777 
778 #define ALLOCATE_ARRAY(Type, name, len, on_no_room) \
779   Type *name = (Type *) scratch; \
780   do { \
781     unsigned int _consumed = DIV_CEIL ((len) * sizeof (Type), sizeof (*scratch)); \
782     if (unlikely (_consumed > scratch_size)) \
783     { \
784       on_no_room; \
785       assert (0); \
786     } \
787     scratch += _consumed; \
788     scratch_size -= _consumed; \
789   } while (0)
790 
791   ALLOCATE_ARRAY (UniChar, pchars, buffer->len * 2, ((void)nullptr) /*nothing*/);
792   unsigned int chars_len = 0;
793   for (unsigned int i = 0; i < buffer->len; i++) {
794     hb_codepoint_t c = buffer->info[i].codepoint;
795     if (likely (c <= 0xFFFFu))
796       pchars[chars_len++] = c;
797     else if (unlikely (c > 0x10FFFFu))
798       pchars[chars_len++] = 0xFFFDu;
799     else {
800       pchars[chars_len++] = 0xD800u + ((c - 0x10000u) >> 10);
801       pchars[chars_len++] = 0xDC00u + ((c - 0x10000u) & ((1u << 10) - 1));
802     }
803   }
804 
805   ALLOCATE_ARRAY (unsigned int, log_clusters, chars_len, ((void)nullptr) /*nothing*/);
806   chars_len = 0;
807   for (unsigned int i = 0; i < buffer->len; i++)
808   {
809     hb_codepoint_t c = buffer->info[i].codepoint;
810     unsigned int cluster = buffer->info[i].cluster;
811     log_clusters[chars_len++] = cluster;
812     if (hb_in_range (c, 0x10000u, 0x10FFFFu))
813       log_clusters[chars_len++] = cluster; /* Surrogates. */
814   }
815 
816 #define FAIL(...) \
817   HB_STMT_START { \
818     DEBUG_MSG (CORETEXT, nullptr, __VA_ARGS__); \
819     ret = false; \
820     goto fail; \
821   } HB_STMT_END
822 
823   bool ret = true;
824   CFStringRef string_ref = nullptr;
825   CTLineRef line = nullptr;
826 
827   if (false)
828   {
829 resize_and_retry:
830     DEBUG_MSG (CORETEXT, buffer, "Buffer resize");
831     /* string_ref uses the scratch-buffer for backing store, and line references
832      * string_ref (via attr_string).  We must release those before resizing buffer. */
833     assert (string_ref);
834     assert (line);
835     CFRelease (string_ref);
836     CFRelease (line);
837     string_ref = nullptr;
838     line = nullptr;
839 
840     /* Get previous start-of-scratch-area, that we use later for readjusting
841      * our existing scratch arrays. */
842     unsigned int old_scratch_used;
843     hb_buffer_t::scratch_buffer_t *old_scratch;
844     old_scratch = buffer->get_scratch_buffer (&old_scratch_used);
845     old_scratch_used = scratch - old_scratch;
846 
847     if (unlikely (!buffer->ensure (buffer->allocated * 2)))
848       FAIL ("Buffer resize failed");
849 
850     /* Adjust scratch, pchars, and log_cluster arrays.  This is ugly, but really the
851      * cleanest way to do without completely restructuring the rest of this shaper. */
852     scratch = buffer->get_scratch_buffer (&scratch_size);
853     pchars = reinterpret_cast<UniChar *> (((char *) scratch + ((char *) pchars - (char *) old_scratch)));
854     log_clusters = reinterpret_cast<unsigned int *> (((char *) scratch + ((char *) log_clusters - (char *) old_scratch)));
855     scratch += old_scratch_used;
856     scratch_size -= old_scratch_used;
857   }
858   {
859     string_ref = CFStringCreateWithCharactersNoCopy (nullptr,
860 						     pchars, chars_len,
861 						     kCFAllocatorNull);
862     if (unlikely (!string_ref))
863       FAIL ("CFStringCreateWithCharactersNoCopy failed");
864 
865     /* Create an attributed string, populate it, and create a line from it, then release attributed string. */
866     {
867       CFMutableAttributedStringRef attr_string = CFAttributedStringCreateMutable (kCFAllocatorDefault,
868 										  chars_len);
869       if (unlikely (!attr_string))
870 	FAIL ("CFAttributedStringCreateMutable failed");
871       CFAttributedStringReplaceString (attr_string, CFRangeMake (0, 0), string_ref);
872       if (HB_DIRECTION_IS_VERTICAL (buffer->props.direction))
873       {
874 	CFAttributedStringSetAttribute (attr_string, CFRangeMake (0, chars_len),
875 					kCTVerticalFormsAttributeName, kCFBooleanTrue);
876       }
877 
878       if (buffer->props.language)
879       {
880 /* What's the iOS equivalent of this check?
881  * The symbols was introduced in iOS 7.0.
882  * At any rate, our fallback is safe and works fine. */
883 #if !(defined(TARGET_OS_IPHONE) && TARGET_OS_IPHONE) && MAC_OS_X_VERSION_MIN_REQUIRED < 1090
884 #  define kCTLanguageAttributeName CFSTR ("NSLanguage")
885 #endif
886 	CFStringRef lang = CFStringCreateWithCStringNoCopy (kCFAllocatorDefault,
887 							    hb_language_to_string (buffer->props.language),
888 							    kCFStringEncodingUTF8,
889 							    kCFAllocatorNull);
890 	if (unlikely (!lang))
891 	{
892 	  CFRelease (attr_string);
893 	  FAIL ("CFStringCreateWithCStringNoCopy failed");
894 	}
895 	CFAttributedStringSetAttribute (attr_string, CFRangeMake (0, chars_len),
896 					kCTLanguageAttributeName, lang);
897 	CFRelease (lang);
898       }
899       CFAttributedStringSetAttribute (attr_string, CFRangeMake (0, chars_len),
900 				      kCTFontAttributeName, ct_font);
901 
902       if (num_features && range_records.length)
903       {
904 	unsigned int start = 0;
905 	range_record_t *last_range = &range_records[0];
906 	for (unsigned int k = 0; k < chars_len; k++)
907 	{
908 	  range_record_t *range = last_range;
909 	  while (log_clusters[k] < range->index_first)
910 	    range--;
911 	  while (log_clusters[k] > range->index_last)
912 	    range++;
913 	  if (range != last_range)
914 	  {
915 	    if (last_range->font)
916 	      CFAttributedStringSetAttribute (attr_string, CFRangeMake (start, k - start),
917 					      kCTFontAttributeName, last_range->font);
918 
919 	    start = k;
920 	  }
921 
922 	  last_range = range;
923 	}
924 	if (start != chars_len && last_range->font)
925 	  CFAttributedStringSetAttribute (attr_string, CFRangeMake (start, chars_len - start),
926 					  kCTFontAttributeName, last_range->font);
927       }
928       /* Enable/disable kern if requested.
929        *
930        * Note: once kern is disabled, reenabling it doesn't currently seem to work in CoreText.
931        */
932       if (num_features)
933       {
934 	unsigned int zeroint = 0;
935 	CFNumberRef zero = CFNumberCreate (kCFAllocatorDefault, kCFNumberIntType, &zeroint);
936 	for (unsigned int i = 0; i < num_features; i++)
937 	{
938 	  const hb_feature_t &feature = features[i];
939 	  if (feature.tag == HB_TAG('k','e','r','n') &&
940 	      feature.start < chars_len && feature.start < feature.end)
941 	  {
942 	    CFRange feature_range = CFRangeMake (feature.start,
943 						 hb_min (feature.end, chars_len) - feature.start);
944 	    if (feature.value)
945 	      CFAttributedStringRemoveAttribute (attr_string, feature_range, kCTKernAttributeName);
946 	    else
947 	      CFAttributedStringSetAttribute (attr_string, feature_range, kCTKernAttributeName, zero);
948 	  }
949 	}
950 	CFRelease (zero);
951       }
952 
953       int level = HB_DIRECTION_IS_FORWARD (buffer->props.direction) ? 0 : 1;
954       CFNumberRef level_number = CFNumberCreate (kCFAllocatorDefault, kCFNumberIntType, &level);
955 #if !(defined(TARGET_OS_IPHONE) && TARGET_OS_IPHONE) && MAC_OS_X_VERSION_MIN_REQUIRED < 1060
956       extern const CFStringRef kCTTypesetterOptionForcedEmbeddingLevel;
957 #endif
958       CFDictionaryRef options = CFDictionaryCreate (kCFAllocatorDefault,
959 						    (const void **) &kCTTypesetterOptionForcedEmbeddingLevel,
960 						    (const void **) &level_number,
961 						    1,
962 						    &kCFTypeDictionaryKeyCallBacks,
963 						    &kCFTypeDictionaryValueCallBacks);
964       CFRelease (level_number);
965       if (unlikely (!options))
966       {
967 	CFRelease (attr_string);
968 	FAIL ("CFDictionaryCreate failed");
969       }
970 
971       CTTypesetterRef typesetter = CTTypesetterCreateWithAttributedStringAndOptions (attr_string, options);
972       CFRelease (options);
973       CFRelease (attr_string);
974       if (unlikely (!typesetter))
975 	FAIL ("CTTypesetterCreateWithAttributedStringAndOptions failed");
976 
977       line = CTTypesetterCreateLine (typesetter, CFRangeMake(0, 0));
978       CFRelease (typesetter);
979       if (unlikely (!line))
980 	FAIL ("CTTypesetterCreateLine failed");
981     }
982 
983     CFArrayRef glyph_runs = CTLineGetGlyphRuns (line);
984     unsigned int num_runs = CFArrayGetCount (glyph_runs);
985     DEBUG_MSG (CORETEXT, nullptr, "Num runs: %d", num_runs);
986 
987     buffer->len = 0;
988     uint32_t status_or = 0;
989     CGFloat advances_so_far = 0;
990     /* For right-to-left runs, CoreText returns the glyphs positioned such that
991      * any trailing whitespace is to the left of (0,0).  Adjust coordinate system
992      * to fix for that.  Test with any RTL string with trailing spaces.
993      * https://crbug.com/469028
994      */
995     if (HB_DIRECTION_IS_BACKWARD (buffer->props.direction))
996     {
997       advances_so_far -= CTLineGetTrailingWhitespaceWidth (line);
998       if (HB_DIRECTION_IS_VERTICAL (buffer->props.direction))
999 	  advances_so_far = -advances_so_far;
1000     }
1001 
1002     const CFRange range_all = CFRangeMake (0, 0);
1003 
1004     for (unsigned int i = 0; i < num_runs; i++)
1005     {
1006       CTRunRef run = static_cast<CTRunRef>(CFArrayGetValueAtIndex (glyph_runs, i));
1007       CTRunStatus run_status = CTRunGetStatus (run);
1008       status_or  |= run_status;
1009       DEBUG_MSG (CORETEXT, run, "CTRunStatus: %x", run_status);
1010       CGFloat run_advance = CTRunGetTypographicBounds (run, range_all, nullptr, nullptr, nullptr);
1011       if (HB_DIRECTION_IS_VERTICAL (buffer->props.direction))
1012 	  run_advance = -run_advance;
1013       DEBUG_MSG (CORETEXT, run, "Run advance: %g", (double) run_advance);
1014 
1015       /* CoreText does automatic font fallback (AKA "cascading") for  characters
1016        * not supported by the requested font, and provides no way to turn it off,
1017        * so we must detect if the returned run uses a font other than the requested
1018        * one and fill in the buffer with .notdef glyphs instead of random glyph
1019        * indices from a different font.
1020        */
1021       CFDictionaryRef attributes = CTRunGetAttributes (run);
1022       CTFontRef run_ct_font = static_cast<CTFontRef>(CFDictionaryGetValue (attributes, kCTFontAttributeName));
1023       if (!CFEqual (run_ct_font, ct_font))
1024       {
1025 	/* The run doesn't use our main font instance.  We have to figure out
1026 	 * whether font fallback happened, or this is just CoreText giving us
1027 	 * another CTFont using the same underlying CGFont.  CoreText seems
1028 	 * to do that in a variety of situations, one of which being vertical
1029 	 * text, but also perhaps for caching reasons.
1030 	 *
1031 	 * First, see if it uses any of our subfonts created to set font features...
1032 	 *
1033 	 * Next, compare the CGFont to the one we used to create our fonts.
1034 	 * Even this doesn't work all the time.
1035 	 *
1036 	 * Finally, we compare PS names, which I don't think are unique...
1037 	 *
1038 	 * Looks like if we really want to be sure here we have to modify the
1039 	 * font to change the name table, similar to what we do in the uniscribe
1040 	 * backend.
1041 	 *
1042 	 * However, even that wouldn't work if we were passed in the CGFont to
1043 	 * construct a hb_face to begin with.
1044 	 *
1045 	 * See: https://github.com/harfbuzz/harfbuzz/pull/36
1046 	 *
1047 	 * Also see: https://bugs.chromium.org/p/chromium/issues/detail?id=597098
1048 	 */
1049 	bool matched = false;
1050 	for (unsigned int i = 0; i < range_records.length; i++)
1051 	  if (range_records[i].font && CFEqual (run_ct_font, range_records[i].font))
1052 	  {
1053 	    matched = true;
1054 	    break;
1055 	  }
1056 	if (!matched)
1057 	{
1058 	  CGFontRef run_cg_font = CTFontCopyGraphicsFont (run_ct_font, nullptr);
1059 	  if (run_cg_font)
1060 	  {
1061 	    matched = CFEqual (run_cg_font, cg_font);
1062 	    CFRelease (run_cg_font);
1063 	  }
1064 	}
1065 	if (!matched)
1066 	{
1067 	  CFStringRef font_ps_name = CTFontCopyName (ct_font, kCTFontPostScriptNameKey);
1068 	  CFStringRef run_ps_name = CTFontCopyName (run_ct_font, kCTFontPostScriptNameKey);
1069 	  CFComparisonResult result = CFStringCompare (run_ps_name, font_ps_name, 0);
1070 	  CFRelease (run_ps_name);
1071 	  CFRelease (font_ps_name);
1072 	  if (result == kCFCompareEqualTo)
1073 	    matched = true;
1074 	}
1075 	if (!matched)
1076 	{
1077 	  CFRange range = CTRunGetStringRange (run);
1078 	  DEBUG_MSG (CORETEXT, run, "Run used fallback font: %ld..%ld",
1079 		     range.location, range.location + range.length);
1080 	  if (!buffer->ensure_inplace (buffer->len + range.length))
1081 	    goto resize_and_retry;
1082 	  hb_glyph_info_t *info = buffer->info + buffer->len;
1083 
1084 	  hb_codepoint_t notdef = 0;
1085 	  hb_direction_t dir = buffer->props.direction;
1086 	  hb_position_t x_advance, y_advance, x_offset, y_offset;
1087 	  hb_font_get_glyph_advance_for_direction (font, notdef, dir, &x_advance, &y_advance);
1088 	  hb_font_get_glyph_origin_for_direction (font, notdef, dir, &x_offset, &y_offset);
1089 	  hb_position_t advance = x_advance + y_advance;
1090 	  x_offset = -x_offset;
1091 	  y_offset = -y_offset;
1092 
1093 	  unsigned int old_len = buffer->len;
1094 	  for (CFIndex j = range.location; j < range.location + range.length; j++)
1095 	  {
1096 	      UniChar ch = CFStringGetCharacterAtIndex (string_ref, j);
1097 	      if (hb_in_range<UniChar> (ch, 0xDC00u, 0xDFFFu) && range.location < j)
1098 	      {
1099 		ch = CFStringGetCharacterAtIndex (string_ref, j - 1);
1100 		if (hb_in_range<UniChar> (ch, 0xD800u, 0xDBFFu))
1101 		  /* This is the second of a surrogate pair.  Don't need .notdef
1102 		   * for this one. */
1103 		  continue;
1104 	      }
1105 	      if (buffer->unicode->is_default_ignorable (ch))
1106 		continue;
1107 
1108 	      info->codepoint = notdef;
1109 	      info->cluster = log_clusters[j];
1110 
1111 	      info->mask = advance;
1112 	      info->var1.i32 = x_offset;
1113 	      info->var2.i32 = y_offset;
1114 
1115 	      info++;
1116 	      buffer->len++;
1117 	  }
1118 	  if (HB_DIRECTION_IS_BACKWARD (buffer->props.direction))
1119 	    buffer->reverse_range (old_len, buffer->len);
1120 	  advances_so_far += run_advance;
1121 	  continue;
1122 	}
1123       }
1124 
1125       unsigned int num_glyphs = CTRunGetGlyphCount (run);
1126       if (num_glyphs == 0)
1127 	continue;
1128 
1129       if (!buffer->ensure_inplace (buffer->len + num_glyphs))
1130 	goto resize_and_retry;
1131 
1132       hb_glyph_info_t *run_info = buffer->info + buffer->len;
1133 
1134       /* Testing used to indicate that CTRunGetGlyphsPtr, etc (almost?) always
1135        * succeed, and so copying data to our own buffer will be rare.  Reports
1136        * have it that this changed in OS X 10.10 Yosemite, and nullptr is returned
1137        * frequently.  At any rate, we can test that codepath by setting USE_PTR
1138        * to false. */
1139 
1140 #define USE_PTR true
1141 
1142 #define SCRATCH_SAVE() \
1143   unsigned int scratch_size_saved = scratch_size; \
1144   hb_buffer_t::scratch_buffer_t *scratch_saved = scratch
1145 
1146 #define SCRATCH_RESTORE() \
1147   scratch_size = scratch_size_saved; \
1148   scratch = scratch_saved
1149 
1150       { /* Setup glyphs */
1151 	SCRATCH_SAVE();
1152 	const CGGlyph* glyphs = USE_PTR ? CTRunGetGlyphsPtr (run) : nullptr;
1153 	if (!glyphs) {
1154 	  ALLOCATE_ARRAY (CGGlyph, glyph_buf, num_glyphs, goto resize_and_retry);
1155 	  CTRunGetGlyphs (run, range_all, glyph_buf);
1156 	  glyphs = glyph_buf;
1157 	}
1158 	const CFIndex* string_indices = USE_PTR ? CTRunGetStringIndicesPtr (run) : nullptr;
1159 	if (!string_indices) {
1160 	  ALLOCATE_ARRAY (CFIndex, index_buf, num_glyphs, goto resize_and_retry);
1161 	  CTRunGetStringIndices (run, range_all, index_buf);
1162 	  string_indices = index_buf;
1163 	}
1164 	hb_glyph_info_t *info = run_info;
1165 	for (unsigned int j = 0; j < num_glyphs; j++)
1166 	{
1167 	  info->codepoint = glyphs[j];
1168 	  info->cluster = log_clusters[string_indices[j]];
1169 	  info++;
1170 	}
1171 	SCRATCH_RESTORE();
1172       }
1173       {
1174 	/* Setup positions.
1175 	 * Note that CoreText does not return advances for glyphs.  As such,
1176 	 * for all but last glyph, we use the delta position to next glyph as
1177 	 * advance (in the advance direction only), and for last glyph we set
1178 	 * whatever is needed to make the whole run's advance add up. */
1179 	SCRATCH_SAVE();
1180 	const CGPoint* positions = USE_PTR ? CTRunGetPositionsPtr (run) : nullptr;
1181 	if (!positions) {
1182 	  ALLOCATE_ARRAY (CGPoint, position_buf, num_glyphs, goto resize_and_retry);
1183 	  CTRunGetPositions (run, range_all, position_buf);
1184 	  positions = position_buf;
1185 	}
1186 	hb_glyph_info_t *info = run_info;
1187 	if (HB_DIRECTION_IS_HORIZONTAL (buffer->props.direction))
1188 	{
1189 	  hb_position_t x_offset = round ((positions[0].x - advances_so_far) * x_mult);
1190 	  for (unsigned int j = 0; j < num_glyphs; j++)
1191 	  {
1192 	    CGFloat advance;
1193 	    if (likely (j + 1 < num_glyphs))
1194 	      advance = positions[j + 1].x - positions[j].x;
1195 	    else /* last glyph */
1196 	      advance = run_advance - (positions[j].x - positions[0].x);
1197 	    /* int cast necessary to pass through negative values. */
1198 	    info->mask = (int) round (advance * x_mult);
1199 	    info->var1.i32 = x_offset;
1200 	    info->var2.i32 = round (positions[j].y * y_mult);
1201 	    info++;
1202 	  }
1203 	}
1204 	else
1205 	{
1206 	  hb_position_t y_offset = round ((positions[0].y - advances_so_far) * y_mult);
1207 	  for (unsigned int j = 0; j < num_glyphs; j++)
1208 	  {
1209 	    CGFloat advance;
1210 	    if (likely (j + 1 < num_glyphs))
1211 	      advance = positions[j + 1].y - positions[j].y;
1212 	    else /* last glyph */
1213 	      advance = run_advance - (positions[j].y - positions[0].y);
1214 	    /* int cast necessary to pass through negative values. */
1215 	    info->mask = (int) round (advance * y_mult);
1216 	    info->var1.i32 = round (positions[j].x * x_mult);
1217 	    info->var2.i32 = y_offset;
1218 	    info++;
1219 	  }
1220 	}
1221 	SCRATCH_RESTORE();
1222 	advances_so_far += run_advance;
1223       }
1224 #undef SCRATCH_RESTORE
1225 #undef SCRATCH_SAVE
1226 #undef USE_PTR
1227 #undef ALLOCATE_ARRAY
1228 
1229       buffer->len += num_glyphs;
1230     }
1231 
1232     buffer->clear_positions ();
1233 
1234     unsigned int count = buffer->len;
1235     hb_glyph_info_t *info = buffer->info;
1236     hb_glyph_position_t *pos = buffer->pos;
1237     if (HB_DIRECTION_IS_HORIZONTAL (buffer->props.direction))
1238       for (unsigned int i = 0; i < count; i++)
1239       {
1240 	pos->x_advance = info->mask;
1241 	pos->x_offset = info->var1.i32;
1242 	pos->y_offset = info->var2.i32;
1243 
1244 	info++; pos++;
1245       }
1246     else
1247       for (unsigned int i = 0; i < count; i++)
1248       {
1249 	pos->y_advance = info->mask;
1250 	pos->x_offset = info->var1.i32;
1251 	pos->y_offset = info->var2.i32;
1252 
1253 	info++; pos++;
1254       }
1255 
1256     /* Fix up clusters so that we never return out-of-order indices;
1257      * if core text has reordered glyphs, we'll merge them to the
1258      * beginning of the reordered cluster.  CoreText is nice enough
1259      * to tell us whenever it has produced nonmonotonic results...
1260      * Note that we assume the input clusters were nonmonotonic to
1261      * begin with.
1262      *
1263      * This does *not* mean we'll form the same clusters as Uniscribe
1264      * or the native OT backend, only that the cluster indices will be
1265      * monotonic in the output buffer. */
1266     if (count > 1 && (status_or & kCTRunStatusNonMonotonic) &&
1267 	buffer->cluster_level != HB_BUFFER_CLUSTER_LEVEL_CHARACTERS)
1268     {
1269       hb_glyph_info_t *info = buffer->info;
1270       if (HB_DIRECTION_IS_FORWARD (buffer->props.direction))
1271       {
1272 	unsigned int cluster = info[count - 1].cluster;
1273 	for (unsigned int i = count - 1; i > 0; i--)
1274 	{
1275 	  cluster = hb_min (cluster, info[i - 1].cluster);
1276 	  info[i - 1].cluster = cluster;
1277 	}
1278       }
1279       else
1280       {
1281 	unsigned int cluster = info[0].cluster;
1282 	for (unsigned int i = 1; i < count; i++)
1283 	{
1284 	  cluster = hb_min (cluster, info[i].cluster);
1285 	  info[i].cluster = cluster;
1286 	}
1287       }
1288     }
1289   }
1290 
1291   /* TODO: Sometimes the above positioning code generates negative
1292    * advance values. Fix them up. Example, with NotoNastaliqUrdu
1293    * font and sequence ابهد. */
1294 
1295   buffer->clear_glyph_flags ();
1296   buffer->unsafe_to_break ();
1297 
1298 #undef FAIL
1299 
1300 fail:
1301   if (string_ref)
1302     CFRelease (string_ref);
1303   if (line)
1304     CFRelease (line);
1305 
1306   for (unsigned int i = 0; i < range_records.length; i++)
1307     if (range_records[i].font)
1308       CFRelease (range_records[i].font);
1309 
1310   return ret;
1311 }
1312 
1313 
1314 #endif
1315