The Tor Browser: gfx/harfbuzz/src/hb-ot-layout-gpos-table.hh@925c144e1f1f (annotated)

gfx/harfbuzz/src/hb-ot-layout-gpos-table.hh@925c144e1f1f (annotated)

gfx/harfbuzz/src/hb-ot-layout-gpos-table.hh

Fri, 16 Jan 2015 18:13:44 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Fri, 16 Jan 2015 18:13:44 +0100
branch: TOR_BUG_9701
changeset 14: 925c144e1f1f
permissions: -rw-r--r--

Integrate suggestion from review to improve consistency with existing code.

 /*
  * Copyright © 2007,2008,2009,2010  Red Hat, Inc.
  * Copyright © 2010,2012,2013  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.
  *
  * Red Hat Author(s): Behdad Esfahbod
  * Google Author(s): Behdad Esfahbod
  */
 #ifndef HB_OT_LAYOUT_GPOS_TABLE_HH
 #define HB_OT_LAYOUT_GPOS_TABLE_HH
 #include "hb-ot-layout-gsubgpos-private.hh"
 namespace OT {
 /* buffer **position** var allocations */
 #define attach_lookback() var.u16[0] /* number of glyphs to go back to attach this glyph to its base */
 #define cursive_chain() var.i16[1] /* character to which this connects, may be positive or negative */
 /* Shared Tables: ValueRecord, Anchor Table, and MarkArray */
 typedef USHORT Value;
 typedef Value ValueRecord[VAR];
 struct ValueFormat : USHORT
 {
   enum Flags {
     xPlacement	= 0x0001,	/* Includes horizontal adjustment for placement */
     yPlacement	= 0x0002,	/* Includes vertical adjustment for placement */
     xAdvance	= 0x0004,	/* Includes horizontal adjustment for advance */
     yAdvance	= 0x0008,	/* Includes vertical adjustment for advance */
     xPlaDevice	= 0x0010,	/* Includes horizontal Device table for placement */
     yPlaDevice	= 0x0020,	/* Includes vertical Device table for placement */
     xAdvDevice	= 0x0040,	/* Includes horizontal Device table for advance */
     yAdvDevice	= 0x0080,	/* Includes vertical Device table for advance */
     ignored	= 0x0F00,	/* Was used in TrueType Open for MM fonts */
     reserved	= 0xF000,	/* For future use */
     devices	= 0x00F0	/* Mask for having any Device table */
   };
 /* All fields are options.  Only those available advance the value pointer. */
 #if 0
   SHORT		xPlacement;		/* Horizontal adjustment for
 					 * placement--in design units */
   SHORT		yPlacement;		/* Vertical adjustment for
 					 * placement--in design units */
   SHORT		xAdvance;		/* Horizontal adjustment for
 					 * advance--in design units (only used
 					 * for horizontal writing) */
   SHORT		yAdvance;		/* Vertical adjustment for advance--in
 					 * design units (only used for vertical
 					 * writing) */
   Offset	xPlaDevice;		/* Offset to Device table for
 					 * horizontal placement--measured from
 					 * beginning of PosTable (may be NULL) */
   Offset	yPlaDevice;		/* Offset to Device table for vertical
 					 * placement--measured from beginning
 					 * of PosTable (may be NULL) */
   Offset	xAdvDevice;		/* Offset to Device table for
 					 * horizontal advance--measured from
 					 * beginning of PosTable (may be NULL) */
   Offset	yAdvDevice;		/* Offset to Device table for vertical
 					 * advance--measured from beginning of
 					 * PosTable (may be NULL) */
 #endif
   inline unsigned int get_len (void) const
   { return _hb_popcount32 ((unsigned int) *this); }
   inline unsigned int get_size (void) const
   { return get_len () * Value::static_size; }
   void apply_value (hb_font_t            *font,
 		    hb_direction_t        direction,
 		    const void           *base,
 		    const Value          *values,
 		    hb_glyph_position_t  &glyph_pos) const
   {
     unsigned int x_ppem, y_ppem;
     unsigned int format = *this;
     hb_bool_t horizontal = HB_DIRECTION_IS_HORIZONTAL (direction);
     if (!format) return;
     if (format & xPlacement) glyph_pos.x_offset  += font->em_scale_x (get_short (values++));
     if (format & yPlacement) glyph_pos.y_offset  += font->em_scale_y (get_short (values++));
     if (format & xAdvance) {
       if (likely (horizontal)) glyph_pos.x_advance += font->em_scale_x (get_short (values));
       values++;
     }
     /* y_advance values grow downward but font-space grows upward, hence negation */
     if (format & yAdvance) {
       if (unlikely (!horizontal)) glyph_pos.y_advance -= font->em_scale_y (get_short (values));
       values++;
     }
     if (!has_device ()) return;
     x_ppem = font->x_ppem;
     y_ppem = font->y_ppem;
     if (!x_ppem && !y_ppem) return;
     /* pixel -> fractional pixel */
     if (format & xPlaDevice) {
       if (x_ppem) glyph_pos.x_offset  += (base + get_device (values)).get_x_delta (font);
       values++;
     }
     if (format & yPlaDevice) {
       if (y_ppem) glyph_pos.y_offset  += (base + get_device (values)).get_y_delta (font);
       values++;
     }
     if (format & xAdvDevice) {
       if (horizontal && x_ppem) glyph_pos.x_advance += (base + get_device (values)).get_x_delta (font);
       values++;
     }
     if (format & yAdvDevice) {
       /* y_advance values grow downward but font-space grows upward, hence negation */
       if (!horizontal && y_ppem) glyph_pos.y_advance -= (base + get_device (values)).get_y_delta (font);
       values++;
     }
   }
   private:
   inline bool sanitize_value_devices (hb_sanitize_context_t *c, void *base, Value *values) {
     unsigned int format = *this;
     if (format & xPlacement) values++;
     if (format & yPlacement) values++;
     if (format & xAdvance)   values++;
     if (format & yAdvance)   values++;
     if ((format & xPlaDevice) && !get_device (values++).sanitize (c, base)) return false;
     if ((format & yPlaDevice) && !get_device (values++).sanitize (c, base)) return false;
     if ((format & xAdvDevice) && !get_device (values++).sanitize (c, base)) return false;
     if ((format & yAdvDevice) && !get_device (values++).sanitize (c, base)) return false;
     return true;
   }
   static inline OffsetTo<Device>& get_device (Value* value)
   { return *CastP<OffsetTo<Device> > (value); }
   static inline const OffsetTo<Device>& get_device (const Value* value)
   { return *CastP<OffsetTo<Device> > (value); }
   static inline const SHORT& get_short (const Value* value)
   { return *CastP<SHORT> (value); }
   public:
   inline bool has_device (void) const {
     unsigned int format = *this;
     return (format & devices) != 0;
   }
   inline bool sanitize_value (hb_sanitize_context_t *c, void *base, Value *values) {
     TRACE_SANITIZE (this);
     return TRACE_RETURN (c->check_range (values, get_size ()) && (!has_device () || sanitize_value_devices (c, base, values)));
   }
   inline bool sanitize_values (hb_sanitize_context_t *c, void *base, Value *values, unsigned int count) {
     TRACE_SANITIZE (this);
     unsigned int len = get_len ();
     if (!c->check_array (values, get_size (), count)) return TRACE_RETURN (false);
     if (!has_device ()) return TRACE_RETURN (true);
     for (unsigned int i = 0; i < count; i++) {
       if (!sanitize_value_devices (c, base, values))
         return TRACE_RETURN (false);
       values += len;
     }
     return TRACE_RETURN (true);
   }
   /* Just sanitize referenced Device tables.  Doesn't check the values themselves. */
   inline bool sanitize_values_stride_unsafe (hb_sanitize_context_t *c, void *base, Value *values, unsigned int count, unsigned int stride) {
     TRACE_SANITIZE (this);
     if (!has_device ()) return TRACE_RETURN (true);
     for (unsigned int i = 0; i < count; i++) {
       if (!sanitize_value_devices (c, base, values))
         return TRACE_RETURN (false);
       values += stride;
     }
     return TRACE_RETURN (true);
   }
 };
 struct AnchorFormat1
 {
   inline void get_anchor (hb_font_t *font, hb_codepoint_t glyph_id HB_UNUSED,
 			  hb_position_t *x, hb_position_t *y) const
   {
       *x = font->em_scale_x (xCoordinate);
       *y = font->em_scale_y (yCoordinate);
   }
   inline bool sanitize (hb_sanitize_context_t *c) {
     TRACE_SANITIZE (this);
     return TRACE_RETURN (c->check_struct (this));
   }
   protected:
   USHORT	format;			/* Format identifier--format = 1 */
   SHORT		xCoordinate;		/* Horizontal value--in design units */
   SHORT		yCoordinate;		/* Vertical value--in design units */
   public:
   DEFINE_SIZE_STATIC (6);
 };
 struct AnchorFormat2
 {
   inline void get_anchor (hb_font_t *font, hb_codepoint_t glyph_id,
 			  hb_position_t *x, hb_position_t *y) const
   {
       unsigned int x_ppem = font->x_ppem;
       unsigned int y_ppem = font->y_ppem;
       hb_position_t cx, cy;
       hb_bool_t ret;
       ret = (x_ppem || y_ppem) &&
              font->get_glyph_contour_point_for_origin (glyph_id, anchorPoint, HB_DIRECTION_LTR, &cx, &cy);
       *x = ret && x_ppem ? cx : font->em_scale_x (xCoordinate);
       *y = ret && y_ppem ? cy : font->em_scale_y (yCoordinate);
   }
   inline bool sanitize (hb_sanitize_context_t *c) {
     TRACE_SANITIZE (this);
     return TRACE_RETURN (c->check_struct (this));
   }
   protected:
   USHORT	format;			/* Format identifier--format = 2 */
   SHORT		xCoordinate;		/* Horizontal value--in design units */
   SHORT		yCoordinate;		/* Vertical value--in design units */
   USHORT	anchorPoint;		/* Index to glyph contour point */
   public:
   DEFINE_SIZE_STATIC (8);
 };
 struct AnchorFormat3
 {
   inline void get_anchor (hb_font_t *font, hb_codepoint_t glyph_id HB_UNUSED,
 			  hb_position_t *x, hb_position_t *y) const
   {
       *x = font->em_scale_x (xCoordinate);
       *y = font->em_scale_y (yCoordinate);
       if (font->x_ppem)
 	*x += (this+xDeviceTable).get_x_delta (font);
       if (font->y_ppem)
 	*y += (this+yDeviceTable).get_x_delta (font);
   }
   inline bool sanitize (hb_sanitize_context_t *c) {
     TRACE_SANITIZE (this);
     return TRACE_RETURN (c->check_struct (this) && xDeviceTable.sanitize (c, this) && yDeviceTable.sanitize (c, this));
   }
   protected:
   USHORT	format;			/* Format identifier--format = 3 */
   SHORT		xCoordinate;		/* Horizontal value--in design units */
   SHORT		yCoordinate;		/* Vertical value--in design units */
   OffsetTo<Device>
 		xDeviceTable;		/* Offset to Device table for X
 					 * coordinate-- from beginning of
 					 * Anchor table (may be NULL) */
   OffsetTo<Device>
 		yDeviceTable;		/* Offset to Device table for Y
 					 * coordinate-- from beginning of
 					 * Anchor table (may be NULL) */
   public:
   DEFINE_SIZE_STATIC (10);
 };
 struct Anchor
 {
   inline void get_anchor (hb_font_t *font, hb_codepoint_t glyph_id,
 			  hb_position_t *x, hb_position_t *y) const
   {
     *x = *y = 0;
     switch (u.format) {
     case 1: u.format1.get_anchor (font, glyph_id, x, y); return;
     case 2: u.format2.get_anchor (font, glyph_id, x, y); return;
     case 3: u.format3.get_anchor (font, glyph_id, x, y); return;
     default:						 return;
     }
   }
   inline bool sanitize (hb_sanitize_context_t *c) {
     TRACE_SANITIZE (this);
     if (!u.format.sanitize (c)) return TRACE_RETURN (false);
     switch (u.format) {
     case 1: return TRACE_RETURN (u.format1.sanitize (c));
     case 2: return TRACE_RETURN (u.format2.sanitize (c));
     case 3: return TRACE_RETURN (u.format3.sanitize (c));
     default:return TRACE_RETURN (true);
     }
   }
   protected:
   union {
   USHORT		format;		/* Format identifier */
   AnchorFormat1		format1;
   AnchorFormat2		format2;
   AnchorFormat3		format3;
   } u;
   public:
   DEFINE_SIZE_UNION (2, format);
 };
 struct AnchorMatrix
 {
   inline const Anchor& get_anchor (unsigned int row, unsigned int col, unsigned int cols, bool *found) const {
     *found = false;
     if (unlikely (row >= rows || col >= cols)) return Null(Anchor);
     *found = !matrix[row * cols + col].is_null ();
     return this+matrix[row * cols + col];
   }
   inline bool sanitize (hb_sanitize_context_t *c, unsigned int cols) {
     TRACE_SANITIZE (this);
     if (!c->check_struct (this)) return TRACE_RETURN (false);
     if (unlikely (rows > 0 && cols >= ((unsigned int) -1) / rows)) return TRACE_RETURN (false);
     unsigned int count = rows * cols;
     if (!c->check_array (matrix, matrix[0].static_size, count)) return TRACE_RETURN (false);
     for (unsigned int i = 0; i < count; i++)
       if (!matrix[i].sanitize (c, this)) return TRACE_RETURN (false);
     return TRACE_RETURN (true);
   }
   USHORT	rows;			/* Number of rows */
   protected:
   OffsetTo<Anchor>
 		matrix[VAR];		/* Matrix of offsets to Anchor tables--
 					 * from beginning of AnchorMatrix table */
   public:
   DEFINE_SIZE_ARRAY (2, matrix);
 };
 struct MarkRecord
 {
   friend struct MarkArray;
   inline bool sanitize (hb_sanitize_context_t *c, void *base) {
     TRACE_SANITIZE (this);
     return TRACE_RETURN (c->check_struct (this) && markAnchor.sanitize (c, base));
   }
   protected:
   USHORT	klass;			/* Class defined for this mark */
   OffsetTo<Anchor>
 		markAnchor;		/* Offset to Anchor table--from
 					 * beginning of MarkArray table */
   public:
   DEFINE_SIZE_STATIC (4);
 };
 struct MarkArray : ArrayOf<MarkRecord>	/* Array of MarkRecords--in Coverage order */
 {
   inline bool apply (hb_apply_context_t *c,
 		     unsigned int mark_index, unsigned int glyph_index,
 		     const AnchorMatrix &anchors, unsigned int class_count,
 		     unsigned int glyph_pos) const
   {
     TRACE_APPLY (this);
     hb_buffer_t *buffer = c->buffer;
     const MarkRecord &record = ArrayOf<MarkRecord>::operator[](mark_index);
     unsigned int mark_class = record.klass;
     const Anchor& mark_anchor = this + record.markAnchor;
     bool found;
     const Anchor& glyph_anchor = anchors.get_anchor (glyph_index, mark_class, class_count, &found);
     /* If this subtable doesn't have an anchor for this base and this class,
      * return false such that the subsequent subtables have a chance at it. */
     if (unlikely (!found)) return TRACE_RETURN (false);
     hb_position_t mark_x, mark_y, base_x, base_y;
     mark_anchor.get_anchor (c->font, buffer->cur().codepoint, &mark_x, &mark_y);
     glyph_anchor.get_anchor (c->font, buffer->info[glyph_pos].codepoint, &base_x, &base_y);
     hb_glyph_position_t &o = buffer->cur_pos();
     o.x_offset = base_x - mark_x;
     o.y_offset = base_y - mark_y;
     o.attach_lookback() = buffer->idx - glyph_pos;
     buffer->idx++;
     return TRACE_RETURN (true);
   }
   inline bool sanitize (hb_sanitize_context_t *c) {
     TRACE_SANITIZE (this);
     return TRACE_RETURN (ArrayOf<MarkRecord>::sanitize (c, this));
   }
 };
 /* Lookups */
 struct SinglePosFormat1
 {
   inline void collect_glyphs (hb_collect_glyphs_context_t *c) const
   {
     TRACE_COLLECT_GLYPHS (this);
     (this+coverage).add_coverage (c->input);
   }
   inline const Coverage &get_coverage (void) const
   {
     return this+coverage;
   }
   inline bool apply (hb_apply_context_t *c) const
   {
     TRACE_APPLY (this);
     hb_buffer_t *buffer = c->buffer;
     unsigned int index = (this+coverage).get_coverage  (buffer->cur().codepoint);
     if (likely (index == NOT_COVERED)) return TRACE_RETURN (false);
     valueFormat.apply_value (c->font, c->direction, this,
 			     values, buffer->cur_pos());
     buffer->idx++;
     return TRACE_RETURN (true);
   }
   inline bool sanitize (hb_sanitize_context_t *c) {
     TRACE_SANITIZE (this);
     return TRACE_RETURN (c->check_struct (this) && coverage.sanitize (c, this) && valueFormat.sanitize_value (c, this, values));
   }
   protected:
   USHORT	format;			/* Format identifier--format = 1 */
   OffsetTo<Coverage>
 		coverage;		/* Offset to Coverage table--from
 					 * beginning of subtable */
   ValueFormat	valueFormat;		/* Defines the types of data in the
 					 * ValueRecord */
   ValueRecord	values;			/* Defines positioning
 					 * value(s)--applied to all glyphs in
 					 * the Coverage table */
   public:
   DEFINE_SIZE_ARRAY (6, values);
 };
 struct SinglePosFormat2
 {
   inline void collect_glyphs (hb_collect_glyphs_context_t *c) const
   {
     TRACE_COLLECT_GLYPHS (this);
     (this+coverage).add_coverage (c->input);
   }
   inline const Coverage &get_coverage (void) const
   {
     return this+coverage;
   }
   inline bool apply (hb_apply_context_t *c) const
   {
     TRACE_APPLY (this);
     hb_buffer_t *buffer = c->buffer;
     unsigned int index = (this+coverage).get_coverage  (buffer->cur().codepoint);
     if (likely (index == NOT_COVERED)) return TRACE_RETURN (false);
     if (likely (index >= valueCount)) return TRACE_RETURN (false);
     valueFormat.apply_value (c->font, c->direction, this,
 			     &values[index * valueFormat.get_len ()],
 			     buffer->cur_pos());
     buffer->idx++;
     return TRACE_RETURN (true);
   }
   inline bool sanitize (hb_sanitize_context_t *c) {
     TRACE_SANITIZE (this);
     return TRACE_RETURN (c->check_struct (this) && coverage.sanitize (c, this) && valueFormat.sanitize_values (c, this, values, valueCount));
   }
   protected:
   USHORT	format;			/* Format identifier--format = 2 */
   OffsetTo<Coverage>
 		coverage;		/* Offset to Coverage table--from
 					 * beginning of subtable */
   ValueFormat	valueFormat;		/* Defines the types of data in the
 					 * ValueRecord */
   USHORT	valueCount;		/* Number of ValueRecords */
   ValueRecord	values;			/* Array of ValueRecords--positioning
 					 * values applied to glyphs */
   public:
   DEFINE_SIZE_ARRAY (8, values);
 };
 struct SinglePos
 {
   template <typename context_t>
   inline typename context_t::return_t dispatch (context_t *c) const
   {
     TRACE_DISPATCH (this);
     switch (u.format) {
     case 1: return TRACE_RETURN (c->dispatch (u.format1));
     case 2: return TRACE_RETURN (c->dispatch (u.format2));
     default:return TRACE_RETURN (c->default_return_value ());
     }
   }
   inline bool sanitize (hb_sanitize_context_t *c) {
     TRACE_SANITIZE (this);
     if (!u.format.sanitize (c)) return TRACE_RETURN (false);
     switch (u.format) {
     case 1: return TRACE_RETURN (u.format1.sanitize (c));
     case 2: return TRACE_RETURN (u.format2.sanitize (c));
     default:return TRACE_RETURN (true);
     }
   }
   protected:
   union {
   USHORT		format;		/* Format identifier */
   SinglePosFormat1	format1;
   SinglePosFormat2	format2;
   } u;
 };
 struct PairValueRecord
 {
   friend struct PairSet;
   protected:
   GlyphID	secondGlyph;		/* GlyphID of second glyph in the
 					 * pair--first glyph is listed in the
 					 * Coverage table */
   ValueRecord	values;			/* Positioning data for the first glyph
 					 * followed by for second glyph */
   public:
   DEFINE_SIZE_ARRAY (2, values);
 };
 struct PairSet
 {
   friend struct PairPosFormat1;
   inline void collect_glyphs (hb_collect_glyphs_context_t *c,
 			      const ValueFormat *valueFormats) const
   {
     TRACE_COLLECT_GLYPHS (this);
     unsigned int len1 = valueFormats[0].get_len ();
     unsigned int len2 = valueFormats[1].get_len ();
     unsigned int record_size = USHORT::static_size * (1 + len1 + len2);
     const PairValueRecord *record = CastP<PairValueRecord> (array);
     unsigned int count = len;
     for (unsigned int i = 0; i < count; i++)
     {
       c->input->add (record->secondGlyph);
       record = &StructAtOffset<PairValueRecord> (record, record_size);
     }
   }
   inline bool apply (hb_apply_context_t *c,
 		     const ValueFormat *valueFormats,
 		     unsigned int pos) const
   {
     TRACE_APPLY (this);
     hb_buffer_t *buffer = c->buffer;
     unsigned int len1 = valueFormats[0].get_len ();
     unsigned int len2 = valueFormats[1].get_len ();
     unsigned int record_size = USHORT::static_size * (1 + len1 + len2);
     const PairValueRecord *record = CastP<PairValueRecord> (array);
     unsigned int count = len;
     for (unsigned int i = 0; i < count; i++)
     {
       /* TODO bsearch */
       if (buffer->info[pos].codepoint == record->secondGlyph)
       {
 	valueFormats[0].apply_value (c->font, c->direction, this,
 				     &record->values[0], buffer->cur_pos());
 	valueFormats[1].apply_value (c->font, c->direction, this,
 				     &record->values[len1], buffer->pos[pos]);
 	if (len2)
 	  pos++;
 	buffer->idx = pos;
 	return TRACE_RETURN (true);
       }
       record = &StructAtOffset<PairValueRecord> (record, record_size);
     }
     return TRACE_RETURN (false);
   }
   struct sanitize_closure_t {
     void *base;
     ValueFormat *valueFormats;
     unsigned int len1; /* valueFormats[0].get_len() */
     unsigned int stride; /* 1 + len1 + len2 */
   };
   inline bool sanitize (hb_sanitize_context_t *c, const sanitize_closure_t *closure) {
     TRACE_SANITIZE (this);
     if (!(c->check_struct (this)
        && c->check_array (array, USHORT::static_size * closure->stride, len))) return TRACE_RETURN (false);
     unsigned int count = len;
     PairValueRecord *record = CastP<PairValueRecord> (array);
     return TRACE_RETURN (closure->valueFormats[0].sanitize_values_stride_unsafe (c, closure->base, &record->values[0], count, closure->stride)
 		      && closure->valueFormats[1].sanitize_values_stride_unsafe (c, closure->base, &record->values[closure->len1], count, closure->stride));
   }
   protected:
   USHORT	len;			/* Number of PairValueRecords */
   USHORT	array[VAR];		/* Array of PairValueRecords--ordered
 					 * by GlyphID of the second glyph */
   public:
   DEFINE_SIZE_ARRAY (2, array);
 };
 struct PairPosFormat1
 {
   inline void collect_glyphs (hb_collect_glyphs_context_t *c) const
   {
     TRACE_COLLECT_GLYPHS (this);
     (this+coverage).add_coverage (c->input);
     unsigned int count = pairSet.len;
     for (unsigned int i = 0; i < count; i++)
       (this+pairSet[i]).collect_glyphs (c, &valueFormat1);
   }
   inline const Coverage &get_coverage (void) const
   {
     return this+coverage;
   }
   inline bool apply (hb_apply_context_t *c) const
   {
     TRACE_APPLY (this);
     hb_buffer_t *buffer = c->buffer;
     hb_apply_context_t::skipping_forward_iterator_t skippy_iter (c, buffer->idx, 1);
     if (skippy_iter.has_no_chance ()) return TRACE_RETURN (false);
     unsigned int index = (this+coverage).get_coverage  (buffer->cur().codepoint);
     if (likely (index == NOT_COVERED)) return TRACE_RETURN (false);
     if (!skippy_iter.next ()) return TRACE_RETURN (false);
     return TRACE_RETURN ((this+pairSet[index]).apply (c, &valueFormat1, skippy_iter.idx));
   }
   inline bool sanitize (hb_sanitize_context_t *c) {
     TRACE_SANITIZE (this);
     unsigned int len1 = valueFormat1.get_len ();
     unsigned int len2 = valueFormat2.get_len ();
     PairSet::sanitize_closure_t closure = {
       this,
       &valueFormat1,
       len1,
 + len1 + len2
     };
     return TRACE_RETURN (c->check_struct (this) && coverage.sanitize (c, this) && pairSet.sanitize (c, this, &closure));
   }
   protected:
   USHORT	format;			/* Format identifier--format = 1 */
   OffsetTo<Coverage>
 		coverage;		/* Offset to Coverage table--from
 					 * beginning of subtable */
   ValueFormat	valueFormat1;		/* Defines the types of data in
 					 * ValueRecord1--for the first glyph
 					 * in the pair--may be zero (0) */
   ValueFormat	valueFormat2;		/* Defines the types of data in
 					 * ValueRecord2--for the second glyph
 					 * in the pair--may be zero (0) */
   OffsetArrayOf<PairSet>
 		pairSet;		/* Array of PairSet tables
 					 * ordered by Coverage Index */
   public:
   DEFINE_SIZE_ARRAY (10, pairSet);
 };
 struct PairPosFormat2
 {
   inline void collect_glyphs (hb_collect_glyphs_context_t *c) const
   {
     TRACE_COLLECT_GLYPHS (this);
     /* (this+coverage).add_coverage (c->input); // Don't need this. */
     unsigned int count1 = class1Count;
     const ClassDef &klass1 = this+classDef1;
     for (unsigned int i = 0; i < count1; i++)
       klass1.add_class (c->input, i);
     unsigned int count2 = class2Count;
     const ClassDef &klass2 = this+classDef2;
     for (unsigned int i = 0; i < count2; i++)
       klass2.add_class (c->input, i);
   }
   inline const Coverage &get_coverage (void) const
   {
     return this+coverage;
   }
   inline bool apply (hb_apply_context_t *c) const
   {
     TRACE_APPLY (this);
     hb_buffer_t *buffer = c->buffer;
     hb_apply_context_t::skipping_forward_iterator_t skippy_iter (c, buffer->idx, 1);
     if (skippy_iter.has_no_chance ()) return TRACE_RETURN (false);
     unsigned int index = (this+coverage).get_coverage  (buffer->cur().codepoint);
     if (likely (index == NOT_COVERED)) return TRACE_RETURN (false);
     if (!skippy_iter.next ()) return TRACE_RETURN (false);
     unsigned int len1 = valueFormat1.get_len ();
     unsigned int len2 = valueFormat2.get_len ();
     unsigned int record_len = len1 + len2;
     unsigned int klass1 = (this+classDef1).get_class (buffer->cur().codepoint);
     unsigned int klass2 = (this+classDef2).get_class (buffer->info[skippy_iter.idx].codepoint);
     if (unlikely (klass1 >= class1Count || klass2 >= class2Count)) return TRACE_RETURN (false);
     const Value *v = &values[record_len * (klass1 * class2Count + klass2)];
     valueFormat1.apply_value (c->font, c->direction, this,
 			      v, buffer->cur_pos());
     valueFormat2.apply_value (c->font, c->direction, this,
 			      v + len1, buffer->pos[skippy_iter.idx]);
     buffer->idx = skippy_iter.idx;
     if (len2)
       buffer->idx++;
     return TRACE_RETURN (true);
   }
   inline bool sanitize (hb_sanitize_context_t *c) {
     TRACE_SANITIZE (this);
     if (!(c->check_struct (this)
        && coverage.sanitize (c, this)
        && classDef1.sanitize (c, this)
        && classDef2.sanitize (c, this))) return TRACE_RETURN (false);
     unsigned int len1 = valueFormat1.get_len ();
     unsigned int len2 = valueFormat2.get_len ();
     unsigned int stride = len1 + len2;
     unsigned int record_size = valueFormat1.get_size () + valueFormat2.get_size ();
     unsigned int count = (unsigned int) class1Count * (unsigned int) class2Count;
     return TRACE_RETURN (c->check_array (values, record_size, count) &&
 			 valueFormat1.sanitize_values_stride_unsafe (c, this, &values[0], count, stride) &&
 			 valueFormat2.sanitize_values_stride_unsafe (c, this, &values[len1], count, stride));
   }
   protected:
   USHORT	format;			/* Format identifier--format = 2 */
   OffsetTo<Coverage>
 		coverage;		/* Offset to Coverage table--from
 					 * beginning of subtable */
   ValueFormat	valueFormat1;		/* ValueRecord definition--for the
 					 * first glyph of the pair--may be zero
 					 * (0) */
   ValueFormat	valueFormat2;		/* ValueRecord definition--for the
 					 * second glyph of the pair--may be
 					 * zero (0) */
   OffsetTo<ClassDef>
 		classDef1;		/* Offset to ClassDef table--from
 					 * beginning of PairPos subtable--for
 					 * the first glyph of the pair */
   OffsetTo<ClassDef>
 		classDef2;		/* Offset to ClassDef table--from
 					 * beginning of PairPos subtable--for
 					 * the second glyph of the pair */
   USHORT	class1Count;		/* Number of classes in ClassDef1
 					 * table--includes Class0 */
   USHORT	class2Count;		/* Number of classes in ClassDef2
 					 * table--includes Class0 */
   ValueRecord	values;			/* Matrix of value pairs:
 					 * class1-major, class2-minor,
 					 * Each entry has value1 and value2 */
   public:
   DEFINE_SIZE_ARRAY (16, values);
 };
 struct PairPos
 {
   template <typename context_t>
   inline typename context_t::return_t dispatch (context_t *c) const
   {
     TRACE_DISPATCH (this);
     switch (u.format) {
     case 1: return TRACE_RETURN (c->dispatch (u.format1));
     case 2: return TRACE_RETURN (c->dispatch (u.format2));
     default:return TRACE_RETURN (c->default_return_value ());
     }
   }
   inline bool sanitize (hb_sanitize_context_t *c) {
     TRACE_SANITIZE (this);
     if (!u.format.sanitize (c)) return TRACE_RETURN (false);
     switch (u.format) {
     case 1: return TRACE_RETURN (u.format1.sanitize (c));
     case 2: return TRACE_RETURN (u.format2.sanitize (c));
     default:return TRACE_RETURN (true);
     }
   }
   protected:
   union {
   USHORT		format;		/* Format identifier */
   PairPosFormat1	format1;
   PairPosFormat2	format2;
   } u;
 };
 struct EntryExitRecord
 {
   friend struct CursivePosFormat1;
   inline bool sanitize (hb_sanitize_context_t *c, void *base) {
     TRACE_SANITIZE (this);
     return TRACE_RETURN (entryAnchor.sanitize (c, base) && exitAnchor.sanitize (c, base));
   }
   protected:
   OffsetTo<Anchor>
 		entryAnchor;		/* Offset to EntryAnchor table--from
 					 * beginning of CursivePos
 					 * subtable--may be NULL */
   OffsetTo<Anchor>
 		exitAnchor;		/* Offset to ExitAnchor table--from
 					 * beginning of CursivePos
 					 * subtable--may be NULL */
   public:
   DEFINE_SIZE_STATIC (4);
 };
 struct CursivePosFormat1
 {
   inline void collect_glyphs (hb_collect_glyphs_context_t *c) const
   {
     TRACE_COLLECT_GLYPHS (this);
     (this+coverage).add_coverage (c->input);
   }
   inline const Coverage &get_coverage (void) const
   {
     return this+coverage;
   }
   inline bool apply (hb_apply_context_t *c) const
   {
     TRACE_APPLY (this);
     hb_buffer_t *buffer = c->buffer;
     /* We don't handle mark glyphs here. */
     if (unlikely (_hb_glyph_info_is_mark (&buffer->cur()))) return TRACE_RETURN (false);
     hb_apply_context_t::skipping_forward_iterator_t skippy_iter (c, buffer->idx, 1);
     if (skippy_iter.has_no_chance ()) return TRACE_RETURN (false);
     const EntryExitRecord &this_record = entryExitRecord[(this+coverage).get_coverage  (buffer->cur().codepoint)];
     if (!this_record.exitAnchor) return TRACE_RETURN (false);
     if (!skippy_iter.next ()) return TRACE_RETURN (false);
     const EntryExitRecord &next_record = entryExitRecord[(this+coverage).get_coverage  (buffer->info[skippy_iter.idx].codepoint)];
     if (!next_record.entryAnchor) return TRACE_RETURN (false);
     unsigned int i = buffer->idx;
     unsigned int j = skippy_iter.idx;
     hb_position_t entry_x, entry_y, exit_x, exit_y;
     (this+this_record.exitAnchor).get_anchor (c->font, buffer->info[i].codepoint, &exit_x, &exit_y);
     (this+next_record.entryAnchor).get_anchor (c->font, buffer->info[j].codepoint, &entry_x, &entry_y);
     hb_glyph_position_t *pos = buffer->pos;
     hb_position_t d;
     /* Main-direction adjustment */
     switch (c->direction) {
       case HB_DIRECTION_LTR:
 	pos[i].x_advance  =  exit_x + pos[i].x_offset;
 	d = entry_x + pos[j].x_offset;
 	pos[j].x_advance -= d;
 	pos[j].x_offset  -= d;
 	break;
       case HB_DIRECTION_RTL:
 	d = exit_x + pos[i].x_offset;
 	pos[i].x_advance -= d;
 	pos[i].x_offset  -= d;
 	pos[j].x_advance  =  entry_x + pos[j].x_offset;
 	break;
       case HB_DIRECTION_TTB:
 	pos[i].y_advance  =  exit_y + pos[i].y_offset;
 	d = entry_y + pos[j].y_offset;
 	pos[j].y_advance -= d;
 	pos[j].y_offset  -= d;
 	break;
       case HB_DIRECTION_BTT:
 	d = exit_y + pos[i].y_offset;
 	pos[i].y_advance -= d;
 	pos[i].y_offset  -= d;
 	pos[j].y_advance  =  entry_y;
 	break;
       case HB_DIRECTION_INVALID:
       default:
 	break;
     }
     /* Cross-direction adjustment */
     if  (c->lookup_props & LookupFlag::RightToLeft) {
       pos[i].cursive_chain() = j - i;
       if (likely (HB_DIRECTION_IS_HORIZONTAL (c->direction)))
 	pos[i].y_offset = entry_y - exit_y;
       else
 	pos[i].x_offset = entry_x - exit_x;
     } else {
       pos[j].cursive_chain() = i - j;
       if (likely (HB_DIRECTION_IS_HORIZONTAL (c->direction)))
 	pos[j].y_offset = exit_y - entry_y;
       else
 	pos[j].x_offset = exit_x - entry_x;
     }
     buffer->idx = j;
     return TRACE_RETURN (true);
   }
   inline bool sanitize (hb_sanitize_context_t *c) {
     TRACE_SANITIZE (this);
     return TRACE_RETURN (coverage.sanitize (c, this) && entryExitRecord.sanitize (c, this));
   }
   protected:
   USHORT	format;			/* Format identifier--format = 1 */
   OffsetTo<Coverage>
 		coverage;		/* Offset to Coverage table--from
 					 * beginning of subtable */
   ArrayOf<EntryExitRecord>
 		entryExitRecord;	/* Array of EntryExit records--in
 					 * Coverage Index order */
   public:
   DEFINE_SIZE_ARRAY (6, entryExitRecord);
 };
 struct CursivePos
 {
   template <typename context_t>
   inline typename context_t::return_t dispatch (context_t *c) const
   {
     TRACE_DISPATCH (this);
     switch (u.format) {
     case 1: return TRACE_RETURN (c->dispatch (u.format1));
     default:return TRACE_RETURN (c->default_return_value ());
     }
   }
   inline bool sanitize (hb_sanitize_context_t *c) {
     TRACE_SANITIZE (this);
     if (!u.format.sanitize (c)) return TRACE_RETURN (false);
     switch (u.format) {
     case 1: return TRACE_RETURN (u.format1.sanitize (c));
     default:return TRACE_RETURN (true);
     }
   }
   protected:
   union {
   USHORT		format;		/* Format identifier */
   CursivePosFormat1	format1;
   } u;
 };
 typedef AnchorMatrix BaseArray;		/* base-major--
 					 * in order of BaseCoverage Index--,
 					 * mark-minor--
 					 * ordered by class--zero-based. */
 struct MarkBasePosFormat1
 {
   inline void collect_glyphs (hb_collect_glyphs_context_t *c) const
   {
     TRACE_COLLECT_GLYPHS (this);
     (this+markCoverage).add_coverage (c->input);
     (this+baseCoverage).add_coverage (c->input);
   }
   inline const Coverage &get_coverage (void) const
   {
     return this+markCoverage;
   }
   inline bool apply (hb_apply_context_t *c) const
   {
     TRACE_APPLY (this);
     hb_buffer_t *buffer = c->buffer;
     unsigned int mark_index = (this+markCoverage).get_coverage  (buffer->cur().codepoint);
     if (likely (mark_index == NOT_COVERED)) return TRACE_RETURN (false);
     /* now we search backwards for a non-mark glyph */
     hb_apply_context_t::skipping_backward_iterator_t skippy_iter (c, buffer->idx, 1);
     skippy_iter.set_lookup_props (LookupFlag::IgnoreMarks);
     do {
       if (!skippy_iter.prev ()) return TRACE_RETURN (false);
       /* We only want to attach to the first of a MultipleSubst sequence.  Reject others. */
       if (0 == _hb_glyph_info_get_lig_comp (&buffer->info[skippy_iter.idx])) break;
       skippy_iter.reject ();
     } while (1);
     /* Checking that matched glyph is actually a base glyph by GDEF is too strong; disabled */
     if (!_hb_glyph_info_is_base_glyph (&buffer->info[skippy_iter.idx])) { /*return TRACE_RETURN (false);*/ }
     unsigned int base_index = (this+baseCoverage).get_coverage  (buffer->info[skippy_iter.idx].codepoint);
     if (base_index == NOT_COVERED) return TRACE_RETURN (false);
     return TRACE_RETURN ((this+markArray).apply (c, mark_index, base_index, this+baseArray, classCount, skippy_iter.idx));
   }
   inline bool sanitize (hb_sanitize_context_t *c) {
     TRACE_SANITIZE (this);
     return TRACE_RETURN (c->check_struct (this) && markCoverage.sanitize (c, this) && baseCoverage.sanitize (c, this) &&
 			 markArray.sanitize (c, this) && baseArray.sanitize (c, this, (unsigned int) classCount));
   }
   protected:
   USHORT	format;			/* Format identifier--format = 1 */
   OffsetTo<Coverage>
 		markCoverage;		/* Offset to MarkCoverage table--from
 					 * beginning of MarkBasePos subtable */
   OffsetTo<Coverage>
 		baseCoverage;		/* Offset to BaseCoverage table--from
 					 * beginning of MarkBasePos subtable */
   USHORT	classCount;		/* Number of classes defined for marks */
   OffsetTo<MarkArray>
 		markArray;		/* Offset to MarkArray table--from
 					 * beginning of MarkBasePos subtable */
   OffsetTo<BaseArray>
 		baseArray;		/* Offset to BaseArray table--from
 					 * beginning of MarkBasePos subtable */
   public:
   DEFINE_SIZE_STATIC (12);
 };
 struct MarkBasePos
 {
   template <typename context_t>
   inline typename context_t::return_t dispatch (context_t *c) const
   {
     TRACE_DISPATCH (this);
     switch (u.format) {
     case 1: return TRACE_RETURN (c->dispatch (u.format1));
     default:return TRACE_RETURN (c->default_return_value ());
     }
   }
   inline bool sanitize (hb_sanitize_context_t *c) {
     TRACE_SANITIZE (this);
     if (!u.format.sanitize (c)) return TRACE_RETURN (false);
     switch (u.format) {
     case 1: return TRACE_RETURN (u.format1.sanitize (c));
     default:return TRACE_RETURN (true);
     }
   }
   protected:
   union {
   USHORT		format;		/* Format identifier */
   MarkBasePosFormat1	format1;
   } u;
 };
 typedef AnchorMatrix LigatureAttach;	/* component-major--
 					 * in order of writing direction--,
 					 * mark-minor--
 					 * ordered by class--zero-based. */
 typedef OffsetListOf<LigatureAttach> LigatureArray;
 					/* Array of LigatureAttach
 					 * tables ordered by
 					 * LigatureCoverage Index */
 struct MarkLigPosFormat1
 {
   inline void collect_glyphs (hb_collect_glyphs_context_t *c) const
   {
     TRACE_COLLECT_GLYPHS (this);
     (this+markCoverage).add_coverage (c->input);
     (this+ligatureCoverage).add_coverage (c->input);
   }
   inline const Coverage &get_coverage (void) const
   {
     return this+markCoverage;
   }
   inline bool apply (hb_apply_context_t *c) const
   {
     TRACE_APPLY (this);
     hb_buffer_t *buffer = c->buffer;
     unsigned int mark_index = (this+markCoverage).get_coverage  (buffer->cur().codepoint);
     if (likely (mark_index == NOT_COVERED)) return TRACE_RETURN (false);
     /* now we search backwards for a non-mark glyph */
     hb_apply_context_t::skipping_backward_iterator_t skippy_iter (c, buffer->idx, 1);
     skippy_iter.set_lookup_props (LookupFlag::IgnoreMarks);
     if (!skippy_iter.prev ()) return TRACE_RETURN (false);
     /* Checking that matched glyph is actually a ligature by GDEF is too strong; disabled */
     if (!_hb_glyph_info_is_ligature (&buffer->info[skippy_iter.idx])) { /*return TRACE_RETURN (false);*/ }
     unsigned int j = skippy_iter.idx;
     unsigned int lig_index = (this+ligatureCoverage).get_coverage  (buffer->info[j].codepoint);
     if (lig_index == NOT_COVERED) return TRACE_RETURN (false);
     const LigatureArray& lig_array = this+ligatureArray;
     const LigatureAttach& lig_attach = lig_array[lig_index];
     /* Find component to attach to */
     unsigned int comp_count = lig_attach.rows;
     if (unlikely (!comp_count)) return TRACE_RETURN (false);
     /* We must now check whether the ligature ID of the current mark glyph
      * is identical to the ligature ID of the found ligature.  If yes, we
      * can directly use the component index.  If not, we attach the mark
      * glyph to the last component of the ligature. */
     unsigned int comp_index;
     unsigned int lig_id = _hb_glyph_info_get_lig_id (&buffer->info[j]);
     unsigned int mark_id = _hb_glyph_info_get_lig_id (&buffer->cur());
     unsigned int mark_comp = _hb_glyph_info_get_lig_comp (&buffer->cur());
     if (lig_id && lig_id == mark_id && mark_comp > 0)
       comp_index = MIN (comp_count, _hb_glyph_info_get_lig_comp (&buffer->cur())) - 1;
     else
       comp_index = comp_count - 1;
     return TRACE_RETURN ((this+markArray).apply (c, mark_index, comp_index, lig_attach, classCount, j));
   }
   inline bool sanitize (hb_sanitize_context_t *c) {
     TRACE_SANITIZE (this);
     return TRACE_RETURN (c->check_struct (this) && markCoverage.sanitize (c, this) && ligatureCoverage.sanitize (c, this) &&
 			 markArray.sanitize (c, this) && ligatureArray.sanitize (c, this, (unsigned int) classCount));
   }
   protected:
   USHORT	format;			/* Format identifier--format = 1 */
   OffsetTo<Coverage>
 		markCoverage;		/* Offset to Mark Coverage table--from
 					 * beginning of MarkLigPos subtable */
   OffsetTo<Coverage>
 		ligatureCoverage;	/* Offset to Ligature Coverage
 					 * table--from beginning of MarkLigPos
 					 * subtable */
   USHORT	classCount;		/* Number of defined mark classes */
   OffsetTo<MarkArray>
 		markArray;		/* Offset to MarkArray table--from
 					 * beginning of MarkLigPos subtable */
   OffsetTo<LigatureArray>
 		ligatureArray;		/* Offset to LigatureArray table--from
 					 * beginning of MarkLigPos subtable */
   public:
   DEFINE_SIZE_STATIC (12);
 };
 struct MarkLigPos
 {
   template <typename context_t>
   inline typename context_t::return_t dispatch (context_t *c) const
   {
     TRACE_DISPATCH (this);
     switch (u.format) {
     case 1: return TRACE_RETURN (c->dispatch (u.format1));
     default:return TRACE_RETURN (c->default_return_value ());
     }
   }
   inline bool sanitize (hb_sanitize_context_t *c) {
     TRACE_SANITIZE (this);
     if (!u.format.sanitize (c)) return TRACE_RETURN (false);
     switch (u.format) {
     case 1: return TRACE_RETURN (u.format1.sanitize (c));
     default:return TRACE_RETURN (true);
     }
   }
   protected:
   union {
   USHORT		format;		/* Format identifier */
   MarkLigPosFormat1	format1;
   } u;
 };
 typedef AnchorMatrix Mark2Array;	/* mark2-major--
 					 * in order of Mark2Coverage Index--,
 					 * mark1-minor--
 					 * ordered by class--zero-based. */
 struct MarkMarkPosFormat1
 {
   inline void collect_glyphs (hb_collect_glyphs_context_t *c) const
   {
     TRACE_COLLECT_GLYPHS (this);
     (this+mark1Coverage).add_coverage (c->input);
     (this+mark2Coverage).add_coverage (c->input);
   }
   inline const Coverage &get_coverage (void) const
   {
     return this+mark1Coverage;
   }
   inline bool apply (hb_apply_context_t *c) const
   {
     TRACE_APPLY (this);
     hb_buffer_t *buffer = c->buffer;
     unsigned int mark1_index = (this+mark1Coverage).get_coverage  (buffer->cur().codepoint);
     if (likely (mark1_index == NOT_COVERED)) return TRACE_RETURN (false);
     /* now we search backwards for a suitable mark glyph until a non-mark glyph */
     hb_apply_context_t::skipping_backward_iterator_t skippy_iter (c, buffer->idx, 1);
     skippy_iter.set_lookup_props (c->lookup_props & ~LookupFlag::IgnoreFlags);
     if (!skippy_iter.prev ()) return TRACE_RETURN (false);
     if (!_hb_glyph_info_is_mark (&buffer->info[skippy_iter.idx])) { return TRACE_RETURN (false); }
     unsigned int j = skippy_iter.idx;
     unsigned int id1 = _hb_glyph_info_get_lig_id (&buffer->cur());
     unsigned int id2 = _hb_glyph_info_get_lig_id (&buffer->info[j]);
     unsigned int comp1 = _hb_glyph_info_get_lig_comp (&buffer->cur());
     unsigned int comp2 = _hb_glyph_info_get_lig_comp (&buffer->info[j]);
     if (likely (id1 == id2)) {
       if (id1 == 0) /* Marks belonging to the same base. */
 	goto good;
       else if (comp1 == comp2) /* Marks belonging to the same ligature component. */
         goto good;
     } else {
       /* If ligature ids don't match, it may be the case that one of the marks
        * itself is a ligature.  In which case match. */
       if ((id1 > 0 && !comp1) || (id2 > 0 && !comp2))
 	goto good;
     }
     /* Didn't match. */
     return TRACE_RETURN (false);
     good:
     unsigned int mark2_index = (this+mark2Coverage).get_coverage  (buffer->info[j].codepoint);
     if (mark2_index == NOT_COVERED) return TRACE_RETURN (false);
     return TRACE_RETURN ((this+mark1Array).apply (c, mark1_index, mark2_index, this+mark2Array, classCount, j));
   }
   inline bool sanitize (hb_sanitize_context_t *c) {
     TRACE_SANITIZE (this);
     return TRACE_RETURN (c->check_struct (this) && mark1Coverage.sanitize (c, this) &&
 			 mark2Coverage.sanitize (c, this) && mark1Array.sanitize (c, this)
 			 && mark2Array.sanitize (c, this, (unsigned int) classCount));
   }
   protected:
   USHORT	format;			/* Format identifier--format = 1 */
   OffsetTo<Coverage>
 		mark1Coverage;		/* Offset to Combining Mark1 Coverage
 					 * table--from beginning of MarkMarkPos
 					 * subtable */
   OffsetTo<Coverage>
 		mark2Coverage;		/* Offset to Combining Mark2 Coverage
 					 * table--from beginning of MarkMarkPos
 					 * subtable */
   USHORT	classCount;		/* Number of defined mark classes */
   OffsetTo<MarkArray>
 		mark1Array;		/* Offset to Mark1Array table--from
 					 * beginning of MarkMarkPos subtable */
   OffsetTo<Mark2Array>
 		mark2Array;		/* Offset to Mark2Array table--from
 					 * beginning of MarkMarkPos subtable */
   public:
   DEFINE_SIZE_STATIC (12);
 };
 struct MarkMarkPos
 {
   template <typename context_t>
   inline typename context_t::return_t dispatch (context_t *c) const
   {
     TRACE_DISPATCH (this);
     switch (u.format) {
     case 1: return TRACE_RETURN (c->dispatch (u.format1));
     default:return TRACE_RETURN (c->default_return_value ());
     }
   }
   inline bool sanitize (hb_sanitize_context_t *c) {
     TRACE_SANITIZE (this);
     if (!u.format.sanitize (c)) return TRACE_RETURN (false);
     switch (u.format) {
     case 1: return TRACE_RETURN (u.format1.sanitize (c));
     default:return TRACE_RETURN (true);
     }
   }
   protected:
   union {
   USHORT		format;		/* Format identifier */
   MarkMarkPosFormat1	format1;
   } u;
 };
 struct ContextPos : Context {};
 struct ChainContextPos : ChainContext {};
 struct ExtensionPos : Extension<ExtensionPos>
 {
   typedef struct PosLookupSubTable LookupSubTable;
 };
 /*
  * PosLookup
  */
 struct PosLookupSubTable
 {
   friend struct PosLookup;
   enum Type {
     Single		= 1,
     Pair		= 2,
     Cursive		= 3,
     MarkBase		= 4,
     MarkLig		= 5,
     MarkMark		= 6,
     Context		= 7,
     ChainContext	= 8,
     Extension		= 9
   };
   template <typename context_t>
   inline typename context_t::return_t dispatch (context_t *c, unsigned int lookup_type) const
   {
     TRACE_DISPATCH (this);
     switch (lookup_type) {
     case Single:		return TRACE_RETURN (u.single.dispatch (c));
     case Pair:			return TRACE_RETURN (u.pair.dispatch (c));
     case Cursive:		return TRACE_RETURN (u.cursive.dispatch (c));
     case MarkBase:		return TRACE_RETURN (u.markBase.dispatch (c));
     case MarkLig:		return TRACE_RETURN (u.markLig.dispatch (c));
     case MarkMark:		return TRACE_RETURN (u.markMark.dispatch (c));
     case Context:		return TRACE_RETURN (u.context.dispatch (c));
     case ChainContext:		return TRACE_RETURN (u.chainContext.dispatch (c));
     case Extension:		return TRACE_RETURN (u.extension.dispatch (c));
     default:			return TRACE_RETURN (c->default_return_value ());
     }
   }
   inline bool sanitize (hb_sanitize_context_t *c, unsigned int lookup_type) {
     TRACE_SANITIZE (this);
     if (!u.header.sub_format.sanitize (c))
       return TRACE_RETURN (false);
     switch (lookup_type) {
     case Single:		return TRACE_RETURN (u.single.sanitize (c));
     case Pair:			return TRACE_RETURN (u.pair.sanitize (c));
     case Cursive:		return TRACE_RETURN (u.cursive.sanitize (c));
     case MarkBase:		return TRACE_RETURN (u.markBase.sanitize (c));
     case MarkLig:		return TRACE_RETURN (u.markLig.sanitize (c));
     case MarkMark:		return TRACE_RETURN (u.markMark.sanitize (c));
     case Context:		return TRACE_RETURN (u.context.sanitize (c));
     case ChainContext:		return TRACE_RETURN (u.chainContext.sanitize (c));
     case Extension:		return TRACE_RETURN (u.extension.sanitize (c));
     default:			return TRACE_RETURN (true);
     }
   }
   protected:
   union {
   struct {
     USHORT		sub_format;
   } header;
   SinglePos		single;
   PairPos		pair;
   CursivePos		cursive;
   MarkBasePos		markBase;
   MarkLigPos		markLig;
   MarkMarkPos		markMark;
   ContextPos		context;
   ChainContextPos	chainContext;
   ExtensionPos		extension;
   } u;
   public:
   DEFINE_SIZE_UNION (2, header.sub_format);
 };
 struct PosLookup : Lookup
 {
   inline const PosLookupSubTable& get_subtable (unsigned int i) const
   { return this+CastR<OffsetArrayOf<PosLookupSubTable> > (subTable)[i]; }
   inline bool is_reverse (void) const
   {
     return false;
   }
   inline hb_collect_glyphs_context_t::return_t collect_glyphs (hb_collect_glyphs_context_t *c) const
   {
     TRACE_COLLECT_GLYPHS (this);
     c->set_recurse_func (NULL);
     return TRACE_RETURN (dispatch (c));
   }
   template <typename set_t>
   inline void add_coverage (set_t *glyphs) const
   {
     hb_get_coverage_context_t c;
     const Coverage *last = NULL;
     unsigned int count = get_subtable_count ();
     for (unsigned int i = 0; i < count; i++) {
       const Coverage *coverage = &get_subtable (i).dispatch (&c, get_type ());
       if (coverage != last) {
         coverage->add_coverage (glyphs);
         last = coverage;
       }
     }
   }
   inline bool apply_once (hb_apply_context_t *c) const
   {
     TRACE_APPLY (this);
     if (!c->check_glyph_property (&c->buffer->cur(), c->lookup_props))
       return TRACE_RETURN (false);
     return TRACE_RETURN (dispatch (c));
   }
   static bool apply_recurse_func (hb_apply_context_t *c, unsigned int lookup_index);
   template <typename context_t>
   static inline typename context_t::return_t dispatch_recurse_func (context_t *c, unsigned int lookup_index);
   template <typename context_t>
   inline typename context_t::return_t dispatch (context_t *c) const
   {
     TRACE_DISPATCH (this);
     unsigned int lookup_type = get_type ();
     unsigned int count = get_subtable_count ();
     for (unsigned int i = 0; i < count; i++) {
       typename context_t::return_t r = get_subtable (i).dispatch (c, lookup_type);
       if (c->stop_sublookup_iteration (r))
         return TRACE_RETURN (r);
     }
     return TRACE_RETURN (c->default_return_value ());
   }
   inline bool sanitize (hb_sanitize_context_t *c) {
     TRACE_SANITIZE (this);
     if (unlikely (!Lookup::sanitize (c))) return TRACE_RETURN (false);
     OffsetArrayOf<PosLookupSubTable> &list = CastR<OffsetArrayOf<PosLookupSubTable> > (subTable);
     return TRACE_RETURN (list.sanitize (c, this, get_type ()));
   }
 };
 typedef OffsetListOf<PosLookup> PosLookupList;
 /*
  * GPOS -- The Glyph Positioning Table
  */
 struct GPOS : GSUBGPOS
 {
   static const hb_tag_t tableTag	= HB_OT_TAG_GPOS;
   inline const PosLookup& get_lookup (unsigned int i) const
   { return CastR<PosLookup> (GSUBGPOS::get_lookup (i)); }
   static inline void position_start (hb_font_t *font, hb_buffer_t *buffer);
   static inline void position_finish (hb_font_t *font, hb_buffer_t *buffer);
   inline bool sanitize (hb_sanitize_context_t *c) {
     TRACE_SANITIZE (this);
     if (unlikely (!GSUBGPOS::sanitize (c))) return TRACE_RETURN (false);
     OffsetTo<PosLookupList> &list = CastR<OffsetTo<PosLookupList> > (lookupList);
     return TRACE_RETURN (list.sanitize (c, this));
   }
   public:
   DEFINE_SIZE_STATIC (10);
 };
 static void
 fix_cursive_minor_offset (hb_glyph_position_t *pos, unsigned int i, hb_direction_t direction)
 {
   unsigned int j = pos[i].cursive_chain();
   if (likely (!j))
     return;
   j += i;
   pos[i].cursive_chain() = 0;
   fix_cursive_minor_offset (pos, j, direction);
   if (HB_DIRECTION_IS_HORIZONTAL (direction))
     pos[i].y_offset += pos[j].y_offset;
   else
     pos[i].x_offset += pos[j].x_offset;
 }
 static void
 fix_mark_attachment (hb_glyph_position_t *pos, unsigned int i, hb_direction_t direction)
 {
   if (likely (!(pos[i].attach_lookback())))
     return;
   unsigned int j = i - pos[i].attach_lookback();
   pos[i].x_offset += pos[j].x_offset;
   pos[i].y_offset += pos[j].y_offset;
   if (HB_DIRECTION_IS_FORWARD (direction))
     for (unsigned int k = j; k < i; k++) {
       pos[i].x_offset -= pos[k].x_advance;
       pos[i].y_offset -= pos[k].y_advance;
     }
   else
     for (unsigned int k = j + 1; k < i + 1; k++) {
       pos[i].x_offset += pos[k].x_advance;
       pos[i].y_offset += pos[k].y_advance;
     }
 }
 void
 GPOS::position_start (hb_font_t *font HB_UNUSED, hb_buffer_t *buffer)
 {
   buffer->clear_positions ();
   unsigned int count = buffer->len;
   for (unsigned int i = 0; i < count; i++)
     buffer->pos[i].attach_lookback() = buffer->pos[i].cursive_chain() = 0;
 }
 void
 GPOS::position_finish (hb_font_t *font HB_UNUSED, hb_buffer_t *buffer)
 {
   unsigned int len;
   hb_glyph_position_t *pos = hb_buffer_get_glyph_positions (buffer, &len);
   hb_direction_t direction = buffer->props.direction;
   /* Handle cursive connections */
   for (unsigned int i = 0; i < len; i++)
     fix_cursive_minor_offset (pos, i, direction);
   /* Handle attachments */
   for (unsigned int i = 0; i < len; i++)
     fix_mark_attachment (pos, i, direction);
   _hb_buffer_deallocate_gsubgpos_vars (buffer);
 }
 /* Out-of-class implementation for methods recursing */
 template <typename context_t>
 inline typename context_t::return_t PosLookup::dispatch_recurse_func (context_t *c, unsigned int lookup_index)
 {
   const GPOS &gpos = *(hb_ot_layout_from_face (c->face)->gpos);
   const PosLookup &l = gpos.get_lookup (lookup_index);
   return l.dispatch (c);
 }
 inline bool PosLookup::apply_recurse_func (hb_apply_context_t *c, unsigned int lookup_index)
 {
   const GPOS &gpos = *(hb_ot_layout_from_face (c->face)->gpos);
   const PosLookup &l = gpos.get_lookup (lookup_index);
   unsigned int saved_lookup_props = c->lookup_props;
   c->set_lookup (l);
   bool ret = l.apply_once (c);
   c->lookup_props = saved_lookup_props;
   return ret;
 }
 #undef attach_lookback
 #undef cursive_chain
 } /* namespace OT */
 #endif /* HB_OT_LAYOUT_GPOS_TABLE_HH */

The Tor Browser / annotate

gfx/harfbuzz/src/hb-ot-layout-gpos-table.hh@925c144e1f1f (annotated)

gfx/harfbuzz/src/hb-ot-layout-gpos-table.hh