tor-browser

hb-coretext-shape.cc (29851B)

---

/*
* Copyright © 2012,2013  Mozilla Foundation.
* Copyright © 2012,2013  Google, Inc.
*
*  This is part of HarfBuzz, a text shaping library.
*
* Permission is hereby granted, without written agreement and without
* license or royalty fees, to use, copy, modify, and distribute this
* software and its documentation for any purpose, provided that the
* above copyright notice and the following two paragraphs appear in
* all copies of this software.
*
* IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
* DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
* ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
* IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
* DAMAGE.
*
* THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
* BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
* FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
* ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
* PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
*
* Mozilla Author(s): Jonathan Kew
* Google Author(s): Behdad Esfahbod
*/

#include "hb.hh"

#ifdef HAVE_CORETEXT

#include "hb-shaper-impl.hh"

#include "hb-coretext.hh"
#include "hb-aat-layout.hh"

hb_coretext_face_data_t *
_hb_coretext_shaper_face_data_create (hb_face_t *face)
{
 CGFontRef cg_font = create_cg_font (face);

 if (unlikely (!cg_font))
 {
   DEBUG_MSG (CORETEXT, face, "CGFont creation failed..");
   return nullptr;
 }

 return (hb_coretext_face_data_t *) cg_font;
}

void
_hb_coretext_shaper_face_data_destroy (hb_coretext_face_data_t *data)
{
 CFRelease ((CGFontRef) data);
}


hb_coretext_font_data_t *
_hb_coretext_shaper_font_data_create (hb_font_t *font)
{
 hb_face_t *face = font->face;
 const hb_coretext_face_data_t *face_data = face->data.coretext;
 if (unlikely (!face_data)) return nullptr;
 CGFontRef cg_font = (CGFontRef) (const void *) face->data.coretext;

 CGFloat font_size = (CGFloat) (font->ptem > 0.f ? font->ptem : HB_CORETEXT_DEFAULT_FONT_SIZE);
 CTFontRef ct_font = create_ct_font (cg_font, font_size);

 if (unlikely (!ct_font))
 {
   DEBUG_MSG (CORETEXT, font, "CGFont creation failed..");
   return nullptr;
 }

 if (font->num_coords)
 {
   CFMutableDictionaryRef variations =
     CFDictionaryCreateMutable (kCFAllocatorDefault,
			 font->num_coords,
			 &kCFTypeDictionaryKeyCallBacks,
			 &kCFTypeDictionaryValueCallBacks);

   unsigned count = font->num_coords;
   for (unsigned i = 0; i < count; i++)
   {
     hb_ot_var_axis_info_t info;
     unsigned int c = 1;
     hb_ot_var_get_axis_infos (font->face, i, &c, &info);

     float v = hb_clamp (font->design_coords[i], info.min_value, info.max_value);

     CFNumberRef tag_number = CFNumberCreate (kCFAllocatorDefault, kCFNumberIntType, &info.tag);
     CFNumberRef value_number = CFNumberCreate (kCFAllocatorDefault, kCFNumberFloatType, &v);
     CFDictionarySetValue (variations, tag_number, value_number);
     CFRelease (tag_number);
     CFRelease (value_number);
   }

   CFDictionaryRef attributes =
     CFDictionaryCreate (kCFAllocatorDefault,
		  (const void **) &kCTFontVariationAttribute,
		  (const void **) &variations,
		  1,
		  &kCFTypeDictionaryKeyCallBacks,
		  &kCFTypeDictionaryValueCallBacks);

   CTFontDescriptorRef varDesc = CTFontDescriptorCreateWithAttributes (attributes);
   CTFontRef new_ct_font = CTFontCreateCopyWithAttributes (ct_font, 0, nullptr, varDesc);

   CFRelease (ct_font);
   CFRelease (attributes);
   CFRelease (variations);
   ct_font = new_ct_font;
 }

 return (hb_coretext_font_data_t *) ct_font;
}

void
_hb_coretext_shaper_font_data_destroy (hb_coretext_font_data_t *data)
{
 CFRelease ((CTFontRef) data);
}

/*
* shaper
*/

struct feature_record_t {
 unsigned int feature;
 unsigned int setting;
};

struct active_feature_t {
 feature_record_t rec;
 unsigned int order;

 HB_INTERNAL static int cmp (const void *pa, const void *pb) {
   const active_feature_t *a = (const active_feature_t *) pa;
   const active_feature_t *b = (const active_feature_t *) pb;
   return a->rec.feature < b->rec.feature ? -1 : a->rec.feature > b->rec.feature ? 1 :
   a->order < b->order ? -1 : a->order > b->order ? 1 :
   a->rec.setting < b->rec.setting ? -1 : a->rec.setting > b->rec.setting ? 1 :
   0;
 }
 bool operator== (const active_feature_t& f) const {
   return cmp (this, &f) == 0;
 }
};

struct feature_event_t {
 unsigned int index;
 bool start;
 active_feature_t feature;

 HB_INTERNAL static int cmp (const void *pa, const void *pb) {
   const feature_event_t *a = (const feature_event_t *) pa;
   const feature_event_t *b = (const feature_event_t *) pb;
   return a->index < b->index ? -1 : a->index > b->index ? 1 :
   a->start < b->start ? -1 : a->start > b->start ? 1 :
   active_feature_t::cmp (&a->feature, &b->feature);
 }
};

struct range_record_t {
 CTFontRef font;
 unsigned int index_first; /* == start */
 unsigned int index_last;  /* == end - 1 */
};


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)
{
 hb_face_t *face = font->face;
 CGFontRef cg_font = (CGFontRef) (const void *) face->data.coretext;
 CTFontRef ct_font = (CTFontRef) (const void *) font->data.coretext;

 CGFloat ct_font_size = CTFontGetSize (ct_font);
 CGFloat x_mult = (CGFloat) font->x_scale / ct_font_size;
 CGFloat y_mult = (CGFloat) font->y_scale / ct_font_size;

 /* Attach marks to their bases, to match the 'ot' shaper.
  * Adapted from a very old version of hb-ot-shape:hb_form_clusters().
  * Note that this only makes us be closer to the 'ot' shaper,
  * but by no means the same.  For example, if there's
  * B1 M1 B2 M2, and B1-B2 form a ligature, M2's cluster will
  * continue pointing to B2 even though B2 was merged into B1's
  * cluster... */
 if (HB_BUFFER_CLUSTER_LEVEL_IS_GRAPHEMES (buffer->cluster_level))
 {
   hb_unicode_funcs_t *unicode = buffer->unicode;
   unsigned int count = buffer->len;
   hb_glyph_info_t *info = buffer->info;
   for (unsigned int i = 1; i < count; i++)
     if (HB_UNICODE_GENERAL_CATEGORY_IS_MARK (unicode->general_category (info[i].codepoint)))
buffer->merge_clusters (i - 1, i + 1);
 }

 hb_vector_t<range_record_t> range_records;

 /*
  * Set up features.
  * (copied + modified from code from hb-uniscribe.cc)
  */
 if (num_features)
 {
   /* Sort features by start/end events. */
   hb_vector_t<feature_event_t> feature_events;
   for (unsigned int i = 0; i < num_features; i++)
   {
     active_feature_t feature;

#if MAC_OS_X_VERSION_MIN_REQUIRED < 101000
     const hb_aat_feature_mapping_t * mapping = hb_aat_layout_find_feature_mapping (features[i].tag);
     if (!mapping)
continue;

     feature.rec.feature = mapping->aatFeatureType;
     feature.rec.setting = features[i].value ? mapping->selectorToEnable : mapping->selectorToDisable;
#else
     feature.rec.feature = features[i].tag;
     feature.rec.setting = features[i].value;
#endif
     feature.order = i;

     feature_event_t *event;

     event = feature_events.push ();
     event->index = features[i].start;
     event->start = true;
     event->feature = feature;

     event = feature_events.push ();
     event->index = features[i].end;
     event->start = false;
     event->feature = feature;
   }
   feature_events.qsort ();
   /* Add a strategic final event. */
   {
     active_feature_t feature;
     feature.rec.feature = HB_TAG_NONE;
     feature.rec.setting = 0;
     feature.order = num_features + 1;

     feature_event_t *event = feature_events.push ();
     event->index = 0; /* This value does magic. */
     event->start = false;
     event->feature = feature;
   }

   /* Scan events and save features for each range. */
   hb_vector_t<active_feature_t> active_features;
   unsigned int last_index = 0;
   for (unsigned int i = 0; i < feature_events.length; i++)
   {
     feature_event_t *event = &feature_events[i];

     if (event->index != last_index)
     {
/* Save a snapshot of active features and the range. */
range_record_t *range = range_records.push ();

if (active_features.length)
{
  CFMutableArrayRef features_array = CFArrayCreateMutable(kCFAllocatorDefault, 0, &kCFTypeArrayCallBacks);

  /* TODO sort and resolve conflicting features? */
  /* active_features.qsort (); */
  for (unsigned int j = 0; j < active_features.length; j++)
  {
#if MAC_OS_X_VERSION_MIN_REQUIRED < 101000
    CFStringRef keys[] = {
      kCTFontFeatureTypeIdentifierKey,
      kCTFontFeatureSelectorIdentifierKey
    };
    CFNumberRef values[] = {
      CFNumberCreate (kCFAllocatorDefault, kCFNumberIntType, &active_features[j].rec.feature),
      CFNumberCreate (kCFAllocatorDefault, kCFNumberIntType, &active_features[j].rec.setting)
    };
#else
    char tag[5] = {HB_UNTAG (active_features[j].rec.feature)};
    CFTypeRef keys[] = {
      kCTFontOpenTypeFeatureTag,
      kCTFontOpenTypeFeatureValue
    };
    CFTypeRef values[] = {
      CFStringCreateWithCString (kCFAllocatorDefault, tag, kCFStringEncodingASCII),
      CFNumberCreate (kCFAllocatorDefault, kCFNumberIntType, &active_features[j].rec.setting)
    };
#endif
    static_assert ((ARRAY_LENGTH_CONST (keys) == ARRAY_LENGTH_CONST (values)), "");
    CFDictionaryRef dict = CFDictionaryCreate (kCFAllocatorDefault,
					       (const void **) keys,
					       (const void **) values,
					       ARRAY_LENGTH (keys),
					       &kCFTypeDictionaryKeyCallBacks,
					       &kCFTypeDictionaryValueCallBacks);
    for (unsigned int i = 0; i < ARRAY_LENGTH (values); i++)
      CFRelease (values[i]);

    CFArrayAppendValue (features_array, dict);
    CFRelease (dict);

  }

  CFDictionaryRef attributes = CFDictionaryCreate (kCFAllocatorDefault,
						   (const void **) &kCTFontFeatureSettingsAttribute,
						   (const void **) &features_array,
						   1,
						   &kCFTypeDictionaryKeyCallBacks,
						   &kCFTypeDictionaryValueCallBacks);
  CFRelease (features_array);

  CTFontDescriptorRef font_desc = CTFontDescriptorCreateWithAttributes (attributes);
  CFRelease (attributes);

  range->font = CTFontCreateCopyWithAttributes (ct_font, 0.0, nullptr, font_desc);
  CFRelease (font_desc);
}
else
{
  range->font = nullptr;
}

range->index_first = last_index;
range->index_last  = event->index - 1;

last_index = event->index;
     }

     if (event->start)
     {
active_features.push (event->feature);
     } else {
active_feature_t *feature = active_features.lsearch (event->feature);
if (feature)
  active_features.remove_ordered (feature - active_features.arrayZ);
     }
   }
 }

 unsigned int scratch_size;
 hb_buffer_t::scratch_buffer_t *scratch = buffer->get_scratch_buffer (&scratch_size);

#define ALLOCATE_ARRAY(Type, name, len, on_no_room) \
 Type *name = (Type *) scratch; \
 do { \
   unsigned int _consumed = DIV_CEIL ((len) * sizeof (Type), sizeof (*scratch)); \
   if (unlikely (_consumed > scratch_size)) \
   { \
     on_no_room; \
     assert (0); \
   } \
   scratch += _consumed; \
   scratch_size -= _consumed; \
 } while (0)

 ALLOCATE_ARRAY (UniChar, pchars, buffer->len * 2, ((void)nullptr) /*nothing*/);
 unsigned int chars_len = 0;
 for (unsigned int i = 0; i < buffer->len; i++) {
   hb_codepoint_t c = buffer->info[i].codepoint;
   if (likely (c <= 0xFFFFu))
     pchars[chars_len++] = c;
   else if (unlikely (c > 0x10FFFFu))
     pchars[chars_len++] = 0xFFFDu;
   else {
     pchars[chars_len++] = 0xD800u + ((c - 0x10000u) >> 10);
     pchars[chars_len++] = 0xDC00u + ((c - 0x10000u) & ((1u << 10) - 1));
   }
 }

 ALLOCATE_ARRAY (unsigned int, log_clusters, chars_len, ((void)nullptr) /*nothing*/);
 chars_len = 0;
 for (unsigned int i = 0; i < buffer->len; i++)
 {
   hb_codepoint_t c = buffer->info[i].codepoint;
   unsigned int cluster = buffer->info[i].cluster;
   log_clusters[chars_len++] = cluster;
   if (hb_in_range (c, 0x10000u, 0x10FFFFu))
     log_clusters[chars_len++] = cluster; /* Surrogates. */
 }

#define FAIL(...) \
 HB_STMT_START { \
   DEBUG_MSG (CORETEXT, nullptr, __VA_ARGS__); \
   ret = false; \
   goto fail; \
 } HB_STMT_END

 bool ret = true;
 CFStringRef string_ref = nullptr;
 CTLineRef line = nullptr;

 if (false)
 {
resize_and_retry:
   DEBUG_MSG (CORETEXT, buffer, "Buffer resize");
   /* string_ref uses the scratch-buffer for backing store, and line references
    * string_ref (via attr_string).  We must release those before resizing buffer. */
   assert (string_ref);
   assert (line);
   CFRelease (string_ref);
   CFRelease (line);
   string_ref = nullptr;
   line = nullptr;

   /* Get previous start-of-scratch-area, that we use later for readjusting
    * our existing scratch arrays. */
   unsigned int old_scratch_used;
   hb_buffer_t::scratch_buffer_t *old_scratch;
   old_scratch = buffer->get_scratch_buffer (&old_scratch_used);
   old_scratch_used = scratch - old_scratch;

   if (unlikely (!buffer->ensure (buffer->allocated * 2)))
     FAIL ("Buffer resize failed");

   /* Adjust scratch, pchars, and log_cluster arrays.  This is ugly, but really the
    * cleanest way to do without completely restructuring the rest of this shaper. */
   scratch = buffer->get_scratch_buffer (&scratch_size);
   pchars = reinterpret_cast<UniChar *> (((char *) scratch + ((char *) pchars - (char *) old_scratch)));
   log_clusters = reinterpret_cast<unsigned int *> (((char *) scratch + ((char *) log_clusters - (char *) old_scratch)));
   scratch += old_scratch_used;
   scratch_size -= old_scratch_used;
 }
 {
   string_ref = CFStringCreateWithCharactersNoCopy (nullptr,
					     pchars, chars_len,
					     kCFAllocatorNull);
   if (unlikely (!string_ref))
     FAIL ("CFStringCreateWithCharactersNoCopy failed");

   /* Create an attributed string, populate it, and create a line from it, then release attributed string. */
   {
     CFMutableAttributedStringRef attr_string = CFAttributedStringCreateMutable (kCFAllocatorDefault,
									  chars_len);
     if (unlikely (!attr_string))
FAIL ("CFAttributedStringCreateMutable failed");
     CFAttributedStringReplaceString (attr_string, CFRangeMake (0, 0), string_ref);
     if (HB_DIRECTION_IS_VERTICAL (buffer->props.direction))
     {
CFAttributedStringSetAttribute (attr_string, CFRangeMake (0, chars_len),
				kCTVerticalFormsAttributeName, kCFBooleanTrue);
     }

     if (buffer->props.language)
     {
/* What's the iOS equivalent of this check?
* The symbols was introduced in iOS 7.0.
* At any rate, our fallback is safe and works fine. */
#if !(defined(TARGET_OS_IPHONE) && TARGET_OS_IPHONE) && MAC_OS_X_VERSION_MIN_REQUIRED < 1090
#  define kCTLanguageAttributeName CFSTR ("NSLanguage")
#endif
CFStringRef lang = CFStringCreateWithCStringNoCopy (kCFAllocatorDefault,
						    hb_language_to_string (buffer->props.language),
						    kCFStringEncodingUTF8,
						    kCFAllocatorNull);
if (unlikely (!lang))
{
  CFRelease (attr_string);
  FAIL ("CFStringCreateWithCStringNoCopy failed");
}
CFAttributedStringSetAttribute (attr_string, CFRangeMake (0, chars_len),
				kCTLanguageAttributeName, lang);
CFRelease (lang);
     }
     CFAttributedStringSetAttribute (attr_string, CFRangeMake (0, chars_len),
			      kCTFontAttributeName, ct_font);

     if (num_features && range_records.length)
     {
unsigned int start = 0;
range_record_t *last_range = &range_records[0];
for (unsigned int k = 0; k < chars_len; k++)
{
  range_record_t *range = last_range;
  while (log_clusters[k] < range->index_first)
    range--;
  while (log_clusters[k] > range->index_last)
    range++;
  if (range != last_range)
  {
    if (last_range->font)
      CFAttributedStringSetAttribute (attr_string, CFRangeMake (start, k - start),
				      kCTFontAttributeName, last_range->font);

    start = k;
  }

  last_range = range;
}
if (start != chars_len && last_range->font)
  CFAttributedStringSetAttribute (attr_string, CFRangeMake (start, chars_len - start),
				  kCTFontAttributeName, last_range->font);
     }
     /* Enable/disable kern if requested.
      *
      * Note: once kern is disabled, reenabling it doesn't currently seem to work in CoreText.
      */
     if (num_features)
     {
unsigned int zeroint = 0;
CFNumberRef zero = CFNumberCreate (kCFAllocatorDefault, kCFNumberIntType, &zeroint);
for (unsigned int i = 0; i < num_features; i++)
{
  const hb_feature_t &feature = features[i];
  if (feature.tag == HB_TAG('k','e','r','n') &&
      feature.start < chars_len && feature.start < feature.end)
  {
    CFRange feature_range = CFRangeMake (feature.start,
					 hb_min (feature.end, chars_len) - feature.start);
    if (feature.value)
      CFAttributedStringRemoveAttribute (attr_string, feature_range, kCTKernAttributeName);
    else
      CFAttributedStringSetAttribute (attr_string, feature_range, kCTKernAttributeName, zero);
  }
}
CFRelease (zero);
     }

     int level = HB_DIRECTION_IS_FORWARD (buffer->props.direction) ? 0 : 1;
     CFNumberRef level_number = CFNumberCreate (kCFAllocatorDefault, kCFNumberIntType, &level);
#if !(defined(TARGET_OS_IPHONE) && TARGET_OS_IPHONE) && MAC_OS_X_VERSION_MIN_REQUIRED < 1060
     extern const CFStringRef kCTTypesetterOptionForcedEmbeddingLevel;
#endif
     CFDictionaryRef options = CFDictionaryCreate (kCFAllocatorDefault,
					    (const void **) &kCTTypesetterOptionForcedEmbeddingLevel,
					    (const void **) &level_number,
					    1,
					    &kCFTypeDictionaryKeyCallBacks,
					    &kCFTypeDictionaryValueCallBacks);
     CFRelease (level_number);
     if (unlikely (!options))
     {
CFRelease (attr_string);
FAIL ("CFDictionaryCreate failed");
     }

     CTTypesetterRef typesetter = CTTypesetterCreateWithAttributedStringAndOptions (attr_string, options);
     CFRelease (options);
     CFRelease (attr_string);
     if (unlikely (!typesetter))
FAIL ("CTTypesetterCreateWithAttributedStringAndOptions failed");

     line = CTTypesetterCreateLine (typesetter, CFRangeMake(0, 0));
     CFRelease (typesetter);
     if (unlikely (!line))
FAIL ("CTTypesetterCreateLine failed");
   }

   CFArrayRef glyph_runs = CTLineGetGlyphRuns (line);
   unsigned int num_runs = CFArrayGetCount (glyph_runs);
   DEBUG_MSG (CORETEXT, nullptr, "Num runs: %u", num_runs);

   buffer->len = 0;
   uint32_t status_or = 0;
   CGFloat advances_so_far = 0;
   /* For right-to-left runs, CoreText returns the glyphs positioned such that
    * any trailing whitespace is to the left of (0,0).  Adjust coordinate system
    * to fix for that.  Test with any RTL string with trailing spaces.
    * https://crbug.com/469028
    */
   if (HB_DIRECTION_IS_BACKWARD (buffer->props.direction))
   {
     advances_so_far -= CTLineGetTrailingWhitespaceWidth (line);
     if (HB_DIRECTION_IS_VERTICAL (buffer->props.direction))
  advances_so_far = -advances_so_far;
   }

   const CFRange range_all = CFRangeMake (0, 0);

   for (unsigned int i = 0; i < num_runs; i++)
   {
     CTRunRef run = static_cast<CTRunRef>(CFArrayGetValueAtIndex (glyph_runs, i));
     CTRunStatus run_status = CTRunGetStatus (run);
     status_or  |= run_status;
     DEBUG_MSG (CORETEXT, run, "CTRunStatus: %x", run_status);
     CGFloat run_advance = CTRunGetTypographicBounds (run, range_all, nullptr, nullptr, nullptr);
     if (HB_DIRECTION_IS_VERTICAL (buffer->props.direction))
  run_advance = -run_advance;
     DEBUG_MSG (CORETEXT, run, "Run advance: %g", (double) run_advance);

     /* CoreText does automatic font fallback (AKA "cascading") for  characters
      * not supported by the requested font, and provides no way to turn it off,
      * so we must detect if the returned run uses a font other than the requested
      * one and fill in the buffer with .notdef glyphs instead of random glyph
      * indices from a different font.
      */
     CFDictionaryRef attributes = CTRunGetAttributes (run);
     CTFontRef run_ct_font = static_cast<CTFontRef>(CFDictionaryGetValue (attributes, kCTFontAttributeName));
     if (!CFEqual (run_ct_font, ct_font))
     {
/* The run doesn't use our main font instance.  We have to figure out
 * whether font fallback happened, or this is just CoreText giving us
 * another CTFont using the same underlying CGFont.  CoreText seems
 * to do that in a variety of situations, one of which being vertical
 * text, but also perhaps for caching reasons.
 *
 * First, see if it uses any of our subfonts created to set font features...
 *
 * Next, compare the CGFont to the one we used to create our fonts.
 * Even this doesn't work all the time.
 *
 * Finally, we compare PS names, which I don't think are unique...
 *
 * Looks like if we really want to be sure here we have to modify the
 * font to change the name table, similar to what we do in the uniscribe
 * backend.
 *
 * However, even that wouldn't work if we were passed in the CGFont to
 * construct a hb_face to begin with.
 *
 * See: https://github.com/harfbuzz/harfbuzz/pull/36
 *
 * Also see: https://bugs.chromium.org/p/chromium/issues/detail?id=597098
 */
bool matched = false;
for (unsigned int i = 0; i < range_records.length; i++)
  if (range_records[i].font && CFEqual (run_ct_font, range_records[i].font))
  {
    matched = true;
    break;
  }
if (!matched)
{
  CGFontRef run_cg_font = CTFontCopyGraphicsFont (run_ct_font, nullptr);
  if (run_cg_font)
  {
    matched = CFEqual (run_cg_font, cg_font);
    CFRelease (run_cg_font);
  }
}
if (!matched)
{
  CFStringRef font_ps_name = CTFontCopyName (ct_font, kCTFontPostScriptNameKey);
  CFStringRef run_ps_name = CTFontCopyName (run_ct_font, kCTFontPostScriptNameKey);
  CFComparisonResult result = CFStringCompare (run_ps_name, font_ps_name, 0);
  CFRelease (run_ps_name);
  CFRelease (font_ps_name);
  if (result == kCFCompareEqualTo)
    matched = true;
}
if (!matched)
{
  CFRange range = CTRunGetStringRange (run);
  DEBUG_MSG (CORETEXT, run, "Run used fallback font: %ld..%ld",
	     range.location, range.location + range.length);
  if (!buffer->ensure_inplace (buffer->len + range.length))
    goto resize_and_retry;
  hb_glyph_info_t *info = buffer->info + buffer->len;

  hb_codepoint_t notdef = 0;
  hb_direction_t dir = buffer->props.direction;
  hb_position_t x_advance, y_advance, x_offset, y_offset;
  hb_font_get_glyph_advance_for_direction (font, notdef, dir, &x_advance, &y_advance);
  hb_font_get_glyph_origin_for_direction (font, notdef, dir, &x_offset, &y_offset);
  hb_position_t advance = x_advance + y_advance;
  x_offset = -x_offset;
  y_offset = -y_offset;

  unsigned int old_len = buffer->len;
  for (CFIndex j = range.location; j < range.location + range.length; j++)
  {
      UniChar ch = CFStringGetCharacterAtIndex (string_ref, j);
      if (hb_in_range<UniChar> (ch, 0xDC00u, 0xDFFFu) && range.location < j)
      {
	ch = CFStringGetCharacterAtIndex (string_ref, j - 1);
	if (hb_in_range<UniChar> (ch, 0xD800u, 0xDBFFu))
	  /* This is the second of a surrogate pair.  Don't need .notdef
	   * for this one. */
	  continue;
      }
      if (buffer->unicode->is_default_ignorable (ch))
	continue;

      info->codepoint = notdef;
      info->cluster = log_clusters[j];

      info->mask = advance;
      info->var1.i32 = x_offset;
      info->var2.i32 = y_offset;

      info++;
      buffer->len++;
  }
  if (HB_DIRECTION_IS_BACKWARD (buffer->props.direction))
    buffer->reverse_range (old_len, buffer->len);
  advances_so_far += run_advance;
  continue;
}
     }

     unsigned int num_glyphs = CTRunGetGlyphCount (run);
     if (num_glyphs == 0)
continue;

     if (!buffer->ensure_inplace (buffer->len + num_glyphs))
goto resize_and_retry;

     hb_glyph_info_t *run_info = buffer->info + buffer->len;

     /* Testing used to indicate that CTRunGetGlyphsPtr, etc (almost?) always
      * succeed, and so copying data to our own buffer will be rare.  Reports
      * have it that this changed in OS X 10.10 Yosemite, and nullptr is returned
      * frequently.  At any rate, we can test that codepath by setting USE_PTR
      * to false. */

#define USE_PTR true

#define SCRATCH_SAVE() \
 unsigned int scratch_size_saved = scratch_size; \
 hb_buffer_t::scratch_buffer_t *scratch_saved = scratch

#define SCRATCH_RESTORE() \
 scratch_size = scratch_size_saved; \
 scratch = scratch_saved

     { /* Setup glyphs */
SCRATCH_SAVE();
const CGGlyph* glyphs = USE_PTR ? CTRunGetGlyphsPtr (run) : nullptr;
if (!glyphs) {
  ALLOCATE_ARRAY (CGGlyph, glyph_buf, num_glyphs, goto resize_and_retry);
  CTRunGetGlyphs (run, range_all, glyph_buf);
  glyphs = glyph_buf;
}
const CFIndex* string_indices = USE_PTR ? CTRunGetStringIndicesPtr (run) : nullptr;
if (!string_indices) {
  ALLOCATE_ARRAY (CFIndex, index_buf, num_glyphs, goto resize_and_retry);
  CTRunGetStringIndices (run, range_all, index_buf);
  string_indices = index_buf;
}
hb_glyph_info_t *info = run_info;
for (unsigned int j = 0; j < num_glyphs; j++)
{
  info->codepoint = glyphs[j];
  info->cluster = log_clusters[string_indices[j]];
  info++;
}
SCRATCH_RESTORE();
     }
     {
/* Setup positions.
 * Note that CoreText does not return advances for glyphs.  As such,
 * for all but last glyph, we use the delta position to next glyph as
 * advance (in the advance direction only), and for last glyph we set
 * whatever is needed to make the whole run's advance add up. */
SCRATCH_SAVE();
const CGPoint* positions = USE_PTR ? CTRunGetPositionsPtr (run) : nullptr;
if (!positions) {
  ALLOCATE_ARRAY (CGPoint, position_buf, num_glyphs, goto resize_and_retry);
  CTRunGetPositions (run, range_all, position_buf);
  positions = position_buf;
}
hb_glyph_info_t *info = run_info;
if (HB_DIRECTION_IS_HORIZONTAL (buffer->props.direction))
{
  hb_position_t x_offset = round ((positions[0].x - advances_so_far) * x_mult);
  for (unsigned int j = 0; j < num_glyphs; j++)
  {
    CGFloat advance;
    if (likely (j + 1 < num_glyphs))
      advance = positions[j + 1].x - positions[j].x;
    else /* last glyph */
      advance = run_advance - (positions[j].x - positions[0].x);
    /* int cast necessary to pass through negative values. */
    info->mask = (int) round (advance * x_mult);
    info->var1.i32 = x_offset;
    info->var2.i32 = round (positions[j].y * y_mult);
    info++;
  }
}
else
{
  hb_position_t y_offset = round ((positions[0].y - advances_so_far) * y_mult);
  for (unsigned int j = 0; j < num_glyphs; j++)
  {
    CGFloat advance;
    if (likely (j + 1 < num_glyphs))
      advance = positions[j + 1].y - positions[j].y;
    else /* last glyph */
      advance = run_advance - (positions[j].y - positions[0].y);
    /* int cast necessary to pass through negative values. */
    info->mask = (int) round (advance * y_mult);
    info->var1.i32 = round (positions[j].x * x_mult);
    info->var2.i32 = y_offset;
    info++;
  }
}
SCRATCH_RESTORE();
advances_so_far += run_advance;
     }
#undef SCRATCH_RESTORE
#undef SCRATCH_SAVE
#undef USE_PTR
#undef ALLOCATE_ARRAY

     buffer->len += num_glyphs;
   }

   buffer->clear_positions ();

   unsigned int count = buffer->len;
   hb_glyph_info_t *info = buffer->info;
   hb_glyph_position_t *pos = buffer->pos;
   if (HB_DIRECTION_IS_HORIZONTAL (buffer->props.direction))
     for (unsigned int i = 0; i < count; i++)
     {
pos->x_advance = info->mask;
pos->x_offset = info->var1.i32;
pos->y_offset = info->var2.i32;

info++; pos++;
     }
   else
     for (unsigned int i = 0; i < count; i++)
     {
pos->y_advance = info->mask;
pos->x_offset = info->var1.i32;
pos->y_offset = info->var2.i32;

info++; pos++;
     }

   /* Fix up clusters so that we never return out-of-order indices;
    * if core text has reordered glyphs, we'll merge them to the
    * beginning of the reordered cluster.  CoreText is nice enough
    * to tell us whenever it has produced nonmonotonic results...
    * Note that we assume the input clusters were nonmonotonic to
    * begin with.
    *
    * This does *not* mean we'll form the same clusters as Uniscribe
    * or the native OT backend, only that the cluster indices will be
    * monotonic in the output buffer. */
   if (count > 1 && (status_or & kCTRunStatusNonMonotonic) &&
HB_BUFFER_CLUSTER_LEVEL_IS_MONOTONE (buffer->cluster_level))
   {
     hb_glyph_info_t *info = buffer->info;
     if (HB_DIRECTION_IS_FORWARD (buffer->props.direction))
     {
unsigned int cluster = info[count - 1].cluster;
for (unsigned int i = count - 1; i > 0; i--)
{
  cluster = hb_min (cluster, info[i - 1].cluster);
  info[i - 1].cluster = cluster;
}
     }
     else
     {
unsigned int cluster = info[0].cluster;
for (unsigned int i = 1; i < count; i++)
{
  cluster = hb_min (cluster, info[i].cluster);
  info[i].cluster = cluster;
}
     }
   }
 }

 /* TODO: Sometimes the above positioning code generates negative
  * advance values. Fix them up. Example, with NotoNastaliqUrdu
  * font and sequence ابهد. */

 buffer->clear_glyph_flags ();
 buffer->unsafe_to_break ();

#undef FAIL

fail:
 if (string_ref)
   CFRelease (string_ref);
 if (line)
   CFRelease (line);

 for (unsigned int i = 0; i < range_records.length; i++)
   if (range_records[i].font)
     CFRelease (range_records[i].font);

 return ret;
}


#endif