kc3-lang/harfbuzz/src/hb-ot-glyf-table.hh

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• Hash : d67ba649
  Author :
  Date : 2019-12-05T13:15:21
  

  Rename hb_array_t::in_range to hb_array_t::check_range
  

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• src/hb-ot-glyf-table.hh

• /*
   * Copyright © 2015  Google, Inc.
   * Copyright © 2019  Adobe Inc.
   * Copyright © 2019  Ebrahim Byagowi
   *
   *  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.
   *
   * Google Author(s): Behdad Esfahbod, Garret Rieger, Roderick Sheeter
   * Adobe Author(s): Michiharu Ariza
   */
  
  #ifndef HB_OT_GLYF_TABLE_HH
  #define HB_OT_GLYF_TABLE_HH
  
  #include "hb-open-type.hh"
  #include "hb-ot-head-table.hh"
  #include "hb-ot-hmtx-table.hh"
  #include "hb-ot-var-gvar-table.hh"
  
  #include <float.h>
  
  namespace OT {
  
  
  /*
   * loca -- Index to Location
   * https://docs.microsoft.com/en-us/typography/opentype/spec/loca
   */
  #define HB_OT_TAG_loca HB_TAG('l','o','c','a')
  
  
  struct loca
  {
    friend struct glyf;
  
    static constexpr hb_tag_t tableTag = HB_OT_TAG_loca;
  
    bool sanitize (hb_sanitize_context_t *c HB_UNUSED) const
    {
      TRACE_SANITIZE (this);
      return_trace (true);
    }
  
    protected:
    UnsizedArrayOf<HBUINT8>
  		dataZ;	/* Location data. */
    public:
    DEFINE_SIZE_MIN (0);	/* In reality, this is UNBOUNDED() type; but since we always
  			 * check the size externally, allow Null() object of it by
  			 * defining it _MIN instead. */
  };
  
  
  /*
   * glyf -- TrueType Glyph Data
   * https://docs.microsoft.com/en-us/typography/opentype/spec/glyf
   */
  #define HB_OT_TAG_glyf HB_TAG('g','l','y','f')
  
  
  struct glyf
  {
    static constexpr hb_tag_t tableTag = HB_OT_TAG_glyf;
  
    bool sanitize (hb_sanitize_context_t *c HB_UNUSED) const
    {
      TRACE_SANITIZE (this);
      /* Runtime checks as eager sanitizing each glyph is costy */
      return_trace (true);
    }
  
    template<typename Iterator,
  	   hb_requires (hb_is_source_of (Iterator, unsigned int))>
    static bool
    _add_loca_and_head (hb_subset_plan_t * plan, Iterator padded_offsets)
    {
      unsigned max_offset = + padded_offsets | hb_reduce(hb_add, 0);
      unsigned num_offsets = padded_offsets.len () + 1;
      bool use_short_loca = max_offset < 0x1FFFF;
      unsigned entry_size = use_short_loca ? 2 : 4;
      char *loca_prime_data = (char *) calloc (entry_size, num_offsets);
  
      if (unlikely (!loca_prime_data)) return false;
  
      DEBUG_MSG (SUBSET, nullptr, "loca entry_size %d num_offsets %d "
  				"max_offset %d size %d",
  	       entry_size, num_offsets, max_offset, entry_size * num_offsets);
  
      if (use_short_loca)
        _write_loca (padded_offsets, 1, hb_array ((HBUINT16*) loca_prime_data, num_offsets));
      else
        _write_loca (padded_offsets, 0, hb_array ((HBUINT32*) loca_prime_data, num_offsets));
  
      hb_blob_t * loca_blob = hb_blob_create (loca_prime_data,
  					    entry_size * num_offsets,
  					    HB_MEMORY_MODE_WRITABLE,
  					    loca_prime_data,
  					    free);
  
      bool result = plan->add_table (HB_OT_TAG_loca, loca_blob)
  		  && _add_head_and_set_loca_version (plan, use_short_loca);
  
      hb_blob_destroy (loca_blob);
      return result;
    }
  
    template<typename IteratorIn, typename IteratorOut,
  	   hb_requires (hb_is_source_of (IteratorIn, unsigned int)),
  	   hb_requires (hb_is_sink_of (IteratorOut, unsigned))>
    static void
    _write_loca (IteratorIn it, unsigned right_shift, IteratorOut dest)
    {
      unsigned int offset = 0;
      dest << 0;
      + it
      | hb_map ([=, &offset] (unsigned int padded_size)
  	      {
  		offset += padded_size;
  		DEBUG_MSG (SUBSET, nullptr, "loca entry offset %d", offset);
  		return offset >> right_shift;
  	      })
      | hb_sink (dest)
      ;
    }
  
    /* requires source of SubsetGlyph complains the identifier isn't declared */
    template <typename Iterator>
    bool serialize (hb_serialize_context_t *c,
  		  Iterator it,
  		  const hb_subset_plan_t *plan)
    {
      TRACE_SERIALIZE (this);
      for (const auto &_ : it) _.serialize (c, plan);
      return_trace (true);
    }
  
    /* Byte region(s) per glyph to output
       unpadded, hints removed if so requested
       If we fail to process a glyph we produce an empty (0-length) glyph */
    bool subset (hb_subset_context_t *c) const
    {
      TRACE_SUBSET (this);
  
      glyf *glyf_prime = c->serializer->start_embed <glyf> ();
      if (unlikely (!c->serializer->check_success (glyf_prime))) return_trace (false);
  
      hb_vector_t<SubsetGlyph> glyphs;
      _populate_subset_glyphs (c->plan, &glyphs);
  
      glyf_prime->serialize (c->serializer, hb_iter (glyphs), c->plan);
  
      auto padded_offsets =
      + hb_iter (glyphs)
      | hb_map (&SubsetGlyph::padded_size)
      ;
  
      if (c->serializer->in_error ()) return_trace (false);
      return_trace (c->serializer->check_success (_add_loca_and_head (c->plan,
  								    padded_offsets)));
    }
  
    template <typename SubsetGlyph>
    void
    _populate_subset_glyphs (const hb_subset_plan_t   *plan,
  			   hb_vector_t<SubsetGlyph> *glyphs /* OUT */) const
    {
      OT::glyf::accelerator_t glyf;
      glyf.init (plan->source);
  
      + hb_range (plan->num_output_glyphs ())
      | hb_map ([&] (hb_codepoint_t new_gid)
  	      {
  		SubsetGlyph subset_glyph = {0};
  		subset_glyph.new_gid = new_gid;
  
  		/* should never fail: all old gids should be mapped */
  		if (!plan->old_gid_for_new_gid (new_gid, &subset_glyph.old_gid))
  		  return subset_glyph;
  
  		subset_glyph.source_glyph = glyf.glyph_for_gid (subset_glyph.old_gid, true);
  		if (plan->drop_hints) subset_glyph.drop_hints_bytes ();
  		else subset_glyph.dest_start = subset_glyph.source_glyph.get_bytes ();
  
  		return subset_glyph;
  	      })
      | hb_sink (glyphs)
      ;
  
      glyf.fini ();
    }
  
    static bool
    _add_head_and_set_loca_version (hb_subset_plan_t *plan, bool use_short_loca)
    {
      hb_blob_t *head_blob = hb_sanitize_context_t ().reference_table<head> (plan->source);
      hb_blob_t *head_prime_blob = hb_blob_copy_writable_or_fail (head_blob);
      hb_blob_destroy (head_blob);
  
      if (unlikely (!head_prime_blob))
        return false;
  
      head *head_prime = (head *) hb_blob_get_data_writable (head_prime_blob, nullptr);
      head_prime->indexToLocFormat = use_short_loca ? 0 : 1;
      bool success = plan->add_table (HB_OT_TAG_head, head_prime_blob);
  
      hb_blob_destroy (head_prime_blob);
      return success;
    }
  
    struct CompositeGlyphChain
    {
      enum composite_glyph_flag_t
      {
        ARG_1_AND_2_ARE_WORDS =      0x0001,
        ARGS_ARE_XY_VALUES =         0x0002,
        ROUND_XY_TO_GRID =           0x0004,
        WE_HAVE_A_SCALE =            0x0008,
        MORE_COMPONENTS =            0x0020,
        WE_HAVE_AN_X_AND_Y_SCALE =   0x0040,
        WE_HAVE_A_TWO_BY_TWO =       0x0080,
        WE_HAVE_INSTRUCTIONS =       0x0100,
        USE_MY_METRICS =             0x0200,
        OVERLAP_COMPOUND =           0x0400,
        SCALED_COMPONENT_OFFSET =    0x0800,
        UNSCALED_COMPONENT_OFFSET =  0x1000
      };
  
      unsigned int get_size () const
      {
        unsigned int size = min_size;
        /* arg1 and 2 are int16 */
        if (flags & ARG_1_AND_2_ARE_WORDS) size += 4;
        /* arg1 and 2 are int8 */
        else size += 2;
  
        /* One x 16 bit (scale) */
        if (flags & WE_HAVE_A_SCALE) size += 2;
        /* Two x 16 bit (xscale, yscale) */
        else if (flags & WE_HAVE_AN_X_AND_Y_SCALE) size += 4;
        /* Four x 16 bit (xscale, scale01, scale10, yscale) */
        else if (flags & WE_HAVE_A_TWO_BY_TWO) size += 8;
  
        return size;
      }
  
      bool is_use_my_metrics () const { return   flags & USE_MY_METRICS; }
      bool is_anchored ()       const { return !(flags & ARGS_ARE_XY_VALUES); }
      void get_anchor_points (unsigned int &point1, unsigned int &point2) const
      {
        const HBUINT8 *p = &StructAfter<const HBUINT8> (glyphIndex);
        if (flags & ARG_1_AND_2_ARE_WORDS)
        {
  	point1 = ((const HBUINT16 *) p)[0];
  	point2 = ((const HBUINT16 *) p)[1];
        }
        else
        {
  	point1 = p[0];
  	point2 = p[1];
        }
      }
  
      void transform_points (contour_point_vector_t &points) const
      {
        float matrix[4];
        contour_point_t trans;
        if (get_transformation (matrix, trans))
        {
  	if (scaled_offsets ())
  	{
  	  points.translate (trans);
  	  points.transform (matrix);
  	}
  	else
  	{
  	  points.transform (matrix);
  	  points.translate (trans);
  	}
        }
      }
  
      protected:
      bool scaled_offsets () const
      { return (flags & (SCALED_COMPONENT_OFFSET | UNSCALED_COMPONENT_OFFSET)) == SCALED_COMPONENT_OFFSET; }
  
      bool get_transformation (float (&matrix)[4], contour_point_t &trans) const
      {
        matrix[0] = matrix[3] = 1.f;
        matrix[1] = matrix[2] = 0.f;
  
        int tx, ty;
        const HBINT8 *p = &StructAfter<const HBINT8> (glyphIndex);
        if (flags & ARG_1_AND_2_ARE_WORDS)
        {
  	tx = *(const HBINT16 *) p;
  	p += HBINT16::static_size;
  	ty = *(const HBINT16 *) p;
  	p += HBINT16::static_size;
        }
        else
        {
  	tx = *p++;
  	ty = *p++;
        }
        if (is_anchored ()) tx = ty = 0;
  
        trans.init ((float) tx, (float) ty);
  
        {
  	const F2DOT14 *points = (const F2DOT14 *) p;
  	if (flags & WE_HAVE_A_SCALE)
  	{
  	  matrix[0] = matrix[3] = points[0].to_float ();
  	  return true;
  	}
  	else if (flags & WE_HAVE_AN_X_AND_Y_SCALE)
  	{
  	  matrix[0] = points[0].to_float ();
  	  matrix[3] = points[1].to_float ();
  	  return true;
  	}
  	else if (flags & WE_HAVE_A_TWO_BY_TWO)
  	{
  	  matrix[0] = points[0].to_float ();
  	  matrix[1] = points[1].to_float ();
  	  matrix[2] = points[2].to_float ();
  	  matrix[3] = points[3].to_float ();
  	  return true;
  	}
        }
        return tx || ty;
      }
  
      public:
      HBUINT16	flags;
      HBGlyphID	glyphIndex;
      public:
      DEFINE_SIZE_MIN (4);
    };
  
    struct composite_iter_t : hb_iter_with_fallback_t<composite_iter_t, const CompositeGlyphChain &>
    {
      typedef const CompositeGlyphChain *__item_t__;
      composite_iter_t (hb_bytes_t glyph_, __item_t__ current_) :
        glyph (glyph_), current (current_)
      { if (!check_range (current)) current = nullptr; }
      composite_iter_t () : glyph (hb_bytes_t ()), current (nullptr) {}
  
      const CompositeGlyphChain &__item__ () const { return *current; }
      bool __more__ () const { return current; }
      void __next__ ()
      {
        if (!(current->flags & CompositeGlyphChain::MORE_COMPONENTS)) { current = nullptr; return; }
  
        const CompositeGlyphChain *possible = &StructAfter<CompositeGlyphChain,
  							 CompositeGlyphChain> (*current);
        if (!check_range (possible)) { current = nullptr; return; }
        current = possible;
      }
      bool operator != (const composite_iter_t& o) const
      { return glyph != o.glyph || current != o.current; }
  
      bool check_range (const CompositeGlyphChain *composite) const
      {
        return glyph.check_range (composite, CompositeGlyphChain::min_size)
  	  && glyph.check_range (composite, composite->get_size ());
      }
  
      private:
      hb_bytes_t glyph;
      __item_t__ current;
    };
  
    struct Glyph
    {
      private:
      struct GlyphHeader
      {
        bool has_data () const { return numberOfContours; }
  
        bool get_extents (hb_font_t *font, hb_codepoint_t gid, hb_glyph_extents_t *extents) const
        {
  	/* Undocumented rasterizer behavior: shift glyph to the left by (lsb - xMin), i.e., xMin = lsb */
  	/* extents->x_bearing = hb_min (glyph_header.xMin, glyph_header.xMax); */
  	extents->x_bearing = font->em_scale_x (font->face->table.hmtx->get_side_bearing (gid));
  	extents->y_bearing = font->em_scale_y (hb_max (yMin, yMax));
  	extents->width     = font->em_scale_x (hb_max (xMin, xMax) - hb_min (xMin, xMax));
  	extents->height    = font->em_scale_y (hb_min (yMin, yMax) - hb_max (yMin, yMax));
  
  	return true;
        }
  
        HBINT16	numberOfContours;
  			/* If the number of contours is
  			 * greater than or equal to zero,
  			 * this is a simple glyph; if negative,
  			 * this is a composite glyph. */
        FWORD	xMin;	/* Minimum x for coordinate data. */
        FWORD	yMin;	/* Minimum y for coordinate data. */
        FWORD	xMax;	/* Maximum x for coordinate data. */
        FWORD	yMax;	/* Maximum y for coordinate data. */
        public:
        DEFINE_SIZE_STATIC (10);
      };
  
      struct SimpleGlyph
      {
        const GlyphHeader &header;
        hb_bytes_t bytes;
        SimpleGlyph (const GlyphHeader &header_, hb_bytes_t bytes_) :
  	header (header_), bytes (bytes_) {}
  
        unsigned int instruction_len_offset () const
        { return GlyphHeader::static_size + 2 * header.numberOfContours; }
  
        unsigned int length (unsigned int instruction_len) const
        { return instruction_len_offset () + 2 + instruction_len; }
  
        unsigned int instructions_length () const
        {
  	unsigned int instruction_length_offset = instruction_len_offset ();
  	if (unlikely (instruction_length_offset + 2 > bytes.length)) return 0;
  
  	const HBUINT16 &instructionLength = StructAtOffset<HBUINT16> (&bytes, instruction_length_offset);
  	/* Out of bounds of the current glyph */
  	if (unlikely (length (instructionLength) > bytes.length)) return 0;
  	return instructionLength;
        }
  
        enum simple_glyph_flag_t
        {
  	FLAG_ON_CURVE  = 0x01,
  	FLAG_X_SHORT   = 0x02,
  	FLAG_Y_SHORT   = 0x04,
  	FLAG_REPEAT    = 0x08,
  	FLAG_X_SAME    = 0x10,
  	FLAG_Y_SAME    = 0x20,
  	FLAG_RESERVED1 = 0x40,
  	FLAG_RESERVED2 = 0x80
        };
  
        const Glyph trim_padding () const
        {
  	/* based on FontTools _g_l_y_f.py::trim */
  	const char *glyph = bytes.arrayZ;
  	const char *glyph_end = glyph + bytes.length;
  	/* simple glyph w/contours, possibly trimmable */
  	glyph += instruction_len_offset ();
  
  	if (unlikely (glyph + 2 >= glyph_end)) return Glyph ();
  	unsigned int num_coordinates = StructAtOffset<HBUINT16> (glyph - 2, 0) + 1;
  	unsigned int num_instructions = StructAtOffset<HBUINT16> (glyph, 0);
  
  	glyph += 2 + num_instructions;
  	if (unlikely (glyph + 2 >= glyph_end)) return Glyph ();
  
  	unsigned int coord_bytes = 0;
  	unsigned int coords_with_flags = 0;
  	while (glyph < glyph_end)
  	{
  	  uint8_t flag = *glyph;
  	  glyph++;
  
  	  unsigned int repeat = 1;
  	  if (flag & FLAG_REPEAT)
  	  {
  	    if (unlikely (glyph >= glyph_end)) return Glyph ();
  	    repeat = *glyph + 1;
  	    glyph++;
  	  }
  
  	  unsigned int xBytes, yBytes;
  	  xBytes = yBytes = 0;
  	  if (flag & FLAG_X_SHORT) xBytes = 1;
  	  else if ((flag & FLAG_X_SAME) == 0) xBytes = 2;
  
  	  if (flag & FLAG_Y_SHORT) yBytes = 1;
  	  else if ((flag & FLAG_Y_SAME) == 0) yBytes = 2;
  
  	  coord_bytes += (xBytes + yBytes) * repeat;
  	  coords_with_flags += repeat;
  	  if (coords_with_flags >= num_coordinates) break;
  	}
  
  	if (unlikely (coords_with_flags != num_coordinates)) return Glyph ();
  	return Glyph (bytes.sub_array (0, bytes.length + coord_bytes - (glyph_end - glyph)));
        }
  
        /* zero instruction length */
        void drop_hints ()
        {
  	GlyphHeader &glyph_header = const_cast<GlyphHeader &> (header);
  	(HBUINT16 &) StructAtOffset<HBUINT16> (&glyph_header, instruction_len_offset ()) = 0;
        }
  
        void drop_hints_bytes (hb_bytes_t &dest_start, hb_bytes_t &dest_end) const
        {
  	unsigned int instructions_len = instructions_length ();
  	unsigned int glyph_length = length (instructions_len);
  	dest_start = bytes.sub_array (0, glyph_length - instructions_len);
  	dest_end = bytes.sub_array (glyph_length, bytes.length - glyph_length);
        }
  
        struct x_setter_t
        {
  	void set (contour_point_t &point, float v) const { point.x = v; }
  	bool is_short (uint8_t flag) const { return flag & FLAG_X_SHORT; }
  	bool is_same  (uint8_t flag) const { return flag & FLAG_X_SAME; }
        };
  
        struct y_setter_t
        {
  	void set (contour_point_t &point, float v) const { point.y = v; }
  	bool is_short (uint8_t flag) const { return flag & FLAG_Y_SHORT; }
  	bool is_same  (uint8_t flag) const { return flag & FLAG_Y_SAME; }
        };
  
        template <typename T>
        static bool read_points (const HBUINT8 *&p /* IN/OUT */,
  			       contour_point_vector_t &points_ /* IN/OUT */,
  			       const hb_bytes_t &bytes)
        {
  	T coord_setter;
  	float v = 0;
  	for (unsigned int i = 0; i < points_.length - PHANTOM_COUNT; i++)
  	{
  	  uint8_t flag = points_[i].flag;
  	  if (coord_setter.is_short (flag))
  	  {
  	    if (unlikely (!bytes.check_range (p))) return false;
  	    if (coord_setter.is_same (flag))
  	      v += *p++;
  	    else
  	      v -= *p++;
  	  }
  	  else
  	  {
  	    if (!coord_setter.is_same (flag))
  	    {
  	      if (unlikely (!bytes.check_range ((const HBUINT16 *) p))) return false;
  	      v += *(const HBINT16 *) p;
  	      p += HBINT16::static_size;
  	    }
  	  }
  	  coord_setter.set (points_[i], v);
  	}
  	return true;
        }
  
        bool get_contour_points (contour_point_vector_t &points_ /* OUT */,
  			       hb_vector_t<unsigned int> &end_points_ /* OUT */,
  			       const bool phantom_only=false) const
        {
  	const HBUINT16 *endPtsOfContours = &StructAfter<HBUINT16> (header);
  	int num_contours = header.numberOfContours;
  	if (unlikely (!bytes.check_range (&endPtsOfContours[num_contours + 1]))) return false;
  	unsigned int num_points = endPtsOfContours[num_contours - 1] + 1;
  
  	points_.resize (num_points + PHANTOM_COUNT);
  	for (unsigned int i = 0; i < points_.length; i++) points_[i].init ();
  	if (phantom_only) return true;
  
  	/* Read simple glyph points if !phantom_only */
  	end_points_.resize (num_contours);
  
  	for (int i = 0; i < num_contours; i++)
  	  end_points_[i] = endPtsOfContours[i];
  
  	/* Skip instructions */
  	const HBUINT8 *p = &StructAtOffset<HBUINT8> (&endPtsOfContours[num_contours + 1],
  						     endPtsOfContours[num_contours]);
  
  	/* Read flags */
  	for (unsigned int i = 0; i < num_points; i++)
  	{
  	  if (unlikely (!bytes.check_range (p))) return false;
  	  uint8_t flag = *p++;
  	  points_[i].flag = flag;
  	  if (flag & FLAG_REPEAT)
  	  {
  	    if (unlikely (!bytes.check_range (p))) return false;
  	    unsigned int repeat_count = *p++;
  	    while ((repeat_count-- > 0) && (++i < num_points))
  	      points_[i].flag = flag;
  	  }
  	}
  
  	/* Read x & y coordinates */
  	return (read_points<x_setter_t> (p, points_, bytes) &&
  		read_points<y_setter_t> (p, points_, bytes));
        }
      };
  
      struct CompositeGlyph
      {
        const GlyphHeader &header;
        hb_bytes_t bytes;
        CompositeGlyph (const GlyphHeader &header_, hb_bytes_t bytes_) :
  	header (header_), bytes (bytes_) {}
  
        composite_iter_t get_iterator () const
        { return composite_iter_t (bytes, &StructAfter<CompositeGlyphChain, GlyphHeader> (header)); }
  
        unsigned int instructions_length (hb_bytes_t bytes) const
        {
  	unsigned int start = bytes.length;
  	unsigned int end = bytes.length;
  	const CompositeGlyphChain *last = nullptr;
  	for (auto &item : get_iterator ())
  	  last = &item;
  	if (unlikely (!last)) return 0;
  
  	if ((uint16_t) last->flags & CompositeGlyphChain::WE_HAVE_INSTRUCTIONS)
  	  start = (char *) last - &bytes + last->get_size ();
  	if (unlikely (start > end)) return 0;
  	return end - start;
        }
  
        /* Trimming for composites not implemented.
         * If removing hints it falls out of that. */
        const Glyph trim_padding () const { return Glyph (bytes); }
  
        /* remove WE_HAVE_INSTRUCTIONS flag from composite glyph */
        void drop_hints ()
        {
  	for (const auto &_ : get_iterator ())
  	  *const_cast<OT::HBUINT16 *> (&_.flags) = (uint16_t) _.flags & ~OT::glyf::CompositeGlyphChain::WE_HAVE_INSTRUCTIONS;
        }
  
        /* Chop instructions off the end */
        void drop_hints_bytes (hb_bytes_t &dest_start) const
        { dest_start = bytes.sub_array (0, bytes.length - instructions_length (bytes)); }
  
        bool get_contour_points (contour_point_vector_t &points_ /* OUT */,
  			       hb_vector_t<unsigned int> &end_points_ /* OUT */,
  			       const bool phantom_only=false) const
        {
  	/* add one pseudo point for each component in composite glyph */
  	unsigned int num_points = hb_len (get_iterator ());
  	points_.resize (num_points + PHANTOM_COUNT);
  	for (unsigned int i = 0; i < points_.length; i++) points_[i].init ();
  	return true;
        }
      };
  
      enum glyph_type_t { EMPTY, SIMPLE, COMPOSITE };
  
      enum phantom_point_index_t
      {
        PHANTOM_LEFT   = 0,
        PHANTOM_RIGHT  = 1,
        PHANTOM_TOP    = 2,
        PHANTOM_BOTTOM = 3,
        PHANTOM_COUNT  = 4
      };
  
      public:
      composite_iter_t get_composite_iterator () const
      {
        if (type != COMPOSITE) return composite_iter_t ();
        return CompositeGlyph (*header, bytes).get_iterator ();
      }
  
      const Glyph trim_padding () const
      {
        switch (type) {
        case COMPOSITE: return CompositeGlyph (*header, bytes).trim_padding ();
        case SIMPLE:    return SimpleGlyph (*header, bytes).trim_padding ();
        default:        return bytes;
        }
      }
  
      void drop_hints ()
      {
        switch (type) {
        case COMPOSITE: CompositeGlyph (*header, bytes).drop_hints (); return;
        case SIMPLE:    SimpleGlyph (*header, bytes).drop_hints (); return;
        default:        return;
        }
      }
  
      void drop_hints_bytes (hb_bytes_t &dest_start, hb_bytes_t &dest_end) const
      {
        switch (type) {
        case COMPOSITE: CompositeGlyph (*header, bytes).drop_hints_bytes (dest_start); return;
        case SIMPLE:    SimpleGlyph (*header, bytes).drop_hints_bytes (dest_start, dest_end); return;
        default:        return;
        }
      }
  
      /* for a simple glyph, return contour end points, flags, along with coordinate points
       * for a composite glyph, return pseudo component points
       * in both cases points trailed with four phantom points
       */
      bool get_contour_points (contour_point_vector_t &points_ /* OUT */,
  			     hb_vector_t<unsigned int> &end_points_ /* OUT */,
  			     const bool phantom_only=false) const
      {
        switch (type) {
        case COMPOSITE: return CompositeGlyph (*header, bytes).get_contour_points (points_, end_points_, phantom_only);
        case SIMPLE:    return SimpleGlyph (*header, bytes).get_contour_points (points_, end_points_, phantom_only);
        default:
  	/* empty glyph */
  	points_.resize (PHANTOM_COUNT);
  	for (unsigned int i = 0; i < points_.length; i++) points_[i].init ();
  	return true;
        }
      }
  
      bool is_simple_glyph ()    const { return type == SIMPLE; }
      bool is_composite_glyph () const { return type == COMPOSITE; }
  
      bool get_extents (hb_font_t *font, hb_codepoint_t gid, hb_glyph_extents_t *extents) const
      {
        if (type == EMPTY) return true; /* Empty glyph; zero extents. */
        return header->get_extents (font, gid, extents);
      }
  
      hb_bytes_t get_bytes ()          const { return bytes; }
      const GlyphHeader &get_header () const { return *header; }
  
      Glyph (hb_bytes_t bytes_ = hb_bytes_t ()) :
        bytes (bytes_), header (bytes.as<GlyphHeader> ())
      {
        int num_contours = header->numberOfContours;
        if (unlikely (num_contours == 0)) type = EMPTY;
        else if (num_contours > 0) type = SIMPLE;
        else type = COMPOSITE; /* negative numbers */
      }
  
      protected:
      hb_bytes_t bytes;
      const GlyphHeader *header;
      unsigned type;
    };
  
    struct accelerator_t
    {
      void init (hb_face_t *face_)
      {
        short_offset = false;
        num_glyphs = 0;
        loca_table = nullptr;
        glyf_table = nullptr;
        face = face_;
        const OT::head &head = *face->table.head;
        if (head.indexToLocFormat > 1 || head.glyphDataFormat > 0)
  	/* Unknown format.  Leave num_glyphs=0, that takes care of disabling us. */
  	return;
        short_offset = 0 == head.indexToLocFormat;
  
        loca_table = hb_sanitize_context_t ().reference_table<loca> (face);
        glyf_table = hb_sanitize_context_t ().reference_table<glyf> (face);
  
        num_glyphs = hb_max (1u, loca_table.get_length () / (short_offset ? 2 : 4)) - 1;
      }
  
      void fini ()
      {
        loca_table.destroy ();
        glyf_table.destroy ();
      }
  
      enum phantom_point_index_t
      {
        PHANTOM_LEFT   = 0,
        PHANTOM_RIGHT  = 1,
        PHANTOM_TOP    = 2,
        PHANTOM_BOTTOM = 3,
        PHANTOM_COUNT  = 4
      };
  
      protected:
  
      void init_phantom_points (hb_codepoint_t gid, hb_array_t<contour_point_t> &phantoms /* IN/OUT */) const
      {
        const Glyph &glyph = glyph_for_gid (gid);
        int h_delta = (int) glyph.get_header ().xMin - face->table.hmtx->get_side_bearing (gid);
        int v_orig  = (int) glyph.get_header ().yMax + face->table.vmtx->get_side_bearing (gid);
        unsigned int h_adv = face->table.hmtx->get_advance (gid);
        unsigned int v_adv = face->table.vmtx->get_advance (gid);
  
        phantoms[PHANTOM_LEFT].x = h_delta;
        phantoms[PHANTOM_RIGHT].x = h_adv + h_delta;
        phantoms[PHANTOM_TOP].y = v_orig;
        phantoms[PHANTOM_BOTTOM].y = v_orig - (int) v_adv;
      }
  
      struct contour_bounds_t
      {
        contour_bounds_t () { min_x = min_y = FLT_MAX; max_x = max_y = -FLT_MAX; }
  
        void add (const contour_point_t &p)
        {
  	min_x = hb_min (min_x, p.x);
  	min_y = hb_min (min_y, p.y);
  	max_x = hb_max (max_x, p.x);
  	max_y = hb_max (max_y, p.y);
        }
  
        bool empty () const { return (min_x >= max_x) || (min_y >= max_y); }
  
        void get_extents (hb_font_t *font, hb_glyph_extents_t *extents)
        {
  	if (unlikely (empty ()))
  	{
  	  extents->width = 0;
  	  extents->x_bearing = 0;
  	  extents->height = 0;
  	  extents->y_bearing = 0;
  	  return;
  	}
  	extents->x_bearing = font->em_scalef_x (min_x);
  	extents->width = font->em_scalef_x (max_x - min_x);
  	extents->y_bearing = font->em_scalef_y (max_y);
  	extents->height = font->em_scalef_y (min_y - max_y);
        }
  
        protected:
        float min_x, min_y, max_x, max_y;
      };
  
  #ifndef HB_NO_VAR
      /* Note: Recursively calls itself.
       * all_points includes phantom points
       */
      bool get_points_var (hb_codepoint_t gid,
  			 const int *coords, unsigned int coord_count,
  			 contour_point_vector_t &all_points /* OUT */,
  			 unsigned int depth = 0) const
      {
        if (unlikely (depth++ > HB_MAX_NESTING_LEVEL)) return false;
        contour_point_vector_t points;
        hb_vector_t<unsigned int> end_points;
        const Glyph &glyph = glyph_for_gid (gid);
        if (unlikely (!glyph.get_contour_points (points, end_points))) return false;
        hb_array_t<contour_point_t> phantoms = points.sub_array (points.length - PHANTOM_COUNT, PHANTOM_COUNT);
        init_phantom_points (gid, phantoms);
        if (unlikely (!face->table.gvar->apply_deltas_to_points (gid, coords, coord_count, points.as_array (), end_points.as_array ()))) return false;
  
        unsigned int comp_index = 0;
        if (glyph.is_simple_glyph ())
  	all_points.extend (points.as_array ());
        else if (glyph.is_composite_glyph ())
        {
  	for (auto &item : glyph.get_composite_iterator ())
  	{
  	  contour_point_vector_t comp_points;
  	  if (unlikely (!get_points_var (item.glyphIndex, coords, coord_count,
  					 comp_points, depth))
  			|| comp_points.length < PHANTOM_COUNT)
  	    return false;
  
  	  /* Copy phantom points from component if USE_MY_METRICS flag set */
  	  if (item.is_use_my_metrics ())
  	    for (unsigned int i = 0; i < PHANTOM_COUNT; i++)
  	      phantoms[i] = comp_points[comp_points.length - PHANTOM_COUNT + i];
  
  	  /* Apply component transformation & translation */
  	  item.transform_points (comp_points);
  
  	  /* Apply translatation from gvar */
  	  comp_points.translate (points[comp_index]);
  
  	  if (item.is_anchored ())
  	  {
  	    unsigned int p1, p2;
  	    item.get_anchor_points (p1, p2);
  	    if (likely (p1 < all_points.length && p2 < comp_points.length))
  	    {
  	      contour_point_t delta;
  	      delta.init (all_points[p1].x - comp_points[p2].x,
  			  all_points[p1].y - comp_points[p2].y);
  
  	      comp_points.translate (delta);
  	    }
  	  }
  
  	  all_points.extend (comp_points.sub_array (0, comp_points.length - PHANTOM_COUNT));
  
  	  comp_index++;
  	}
  
  	all_points.extend (phantoms);
        }
        else return false;
  
        return true;
      }
  
      bool get_points_bearing_applied (hb_font_t *font, hb_codepoint_t gid, contour_point_vector_t &all_points) const
      {
        if (unlikely (!get_points_var (gid, font->coords, font->num_coords, all_points) ||
  		    all_points.length < PHANTOM_COUNT)) return false;
  
        /* Undocumented rasterizer behavior:
         * Shift points horizontally by the updated left side bearing
         */
        contour_point_t delta;
        delta.init (-all_points[all_points.length - PHANTOM_COUNT + PHANTOM_LEFT].x, 0.f);
        if (delta.x) all_points.translate (delta);
        return true;
      }
  
      protected:
  
      bool get_var_extents_and_phantoms (hb_font_t *font, hb_codepoint_t gid,
  				       hb_glyph_extents_t *extents=nullptr /* OUT */,
  				       contour_point_vector_t *phantoms=nullptr /* OUT */) const
      {
        contour_point_vector_t all_points;
        if (!unlikely (get_points_bearing_applied (font, gid, all_points))) return false;
        if (extents)
        {
  	contour_bounds_t bounds;
  	for (unsigned int i = 0; i + PHANTOM_COUNT < all_points.length; i++)
  	  bounds.add (all_points[i]);
  	bounds.get_extents (font, extents);
        }
        if (phantoms)
  	for (unsigned int i = 0; i < PHANTOM_COUNT; i++)
  	  (*phantoms)[i] = all_points[all_points.length - PHANTOM_COUNT + i];
        return true;
      }
  
      bool get_var_metrics (hb_font_t *font, hb_codepoint_t gid,
  			  contour_point_vector_t &phantoms) const
      { return get_var_extents_and_phantoms (font, gid, nullptr, &phantoms); }
  
      bool get_extents_var (hb_font_t *font, hb_codepoint_t gid,
  			  hb_glyph_extents_t *extents) const
      { return get_var_extents_and_phantoms (font, gid, extents); }
  #endif
  
      public:
  #ifndef HB_NO_VAR
      unsigned int get_advance_var (hb_font_t *font, hb_codepoint_t gid,
  				  bool is_vertical) const
      {
        bool success = false;
        contour_point_vector_t phantoms;
        phantoms.resize (PHANTOM_COUNT);
  
        if (likely (font->num_coords == face->table.gvar->get_axis_count ()))
  	success = get_var_metrics (font, gid, phantoms);
  
        if (unlikely (!success))
  	return is_vertical ? face->table.vmtx->get_advance (gid) : face->table.hmtx->get_advance (gid);
  
        if (is_vertical)
  	return roundf (phantoms[PHANTOM_TOP].y - phantoms[PHANTOM_BOTTOM].y);
        else
  	return roundf (phantoms[PHANTOM_RIGHT].x - phantoms[PHANTOM_LEFT].x);
      }
  
      int get_side_bearing_var (hb_font_t *font, hb_codepoint_t gid, bool is_vertical) const
      {
        hb_glyph_extents_t extents;
        contour_point_vector_t phantoms;
        phantoms.resize (PHANTOM_COUNT);
  
        if (unlikely (!get_var_extents_and_phantoms (font, gid, &extents, &phantoms)))
  	return is_vertical ? face->table.vmtx->get_side_bearing (gid) : face->table.hmtx->get_side_bearing (gid);
  
        return is_vertical ? ceil (phantoms[PHANTOM_TOP].y) - extents.y_bearing : floor (phantoms[PHANTOM_LEFT].x);
      }
  #endif
  
      bool get_extents (hb_font_t *font, hb_codepoint_t gid, hb_glyph_extents_t *extents) const
      {
  #ifndef HB_NO_VAR
        unsigned int coord_count;
        const int *coords = hb_font_get_var_coords_normalized (font, &coord_count);
        if (coords && coord_count > 0 && coord_count == face->table.gvar->get_axis_count ())
  	return get_extents_var (font, gid, extents);
  #endif
  
        if (unlikely (gid >= num_glyphs)) return false;
  
        return glyph_for_gid (gid).get_extents (font, gid, extents);
      }
  
      const Glyph
      glyph_for_gid (hb_codepoint_t gid, bool needs_padding_removal = false) const
      {
        unsigned int start_offset, end_offset;
        if (unlikely (gid >= num_glyphs)) return Glyph ();
  
        if (short_offset)
        {
  	const HBUINT16 *offsets = (const HBUINT16 *) loca_table->dataZ.arrayZ;
  	start_offset = 2 * offsets[gid];
  	end_offset   = 2 * offsets[gid + 1];
        }
        else
        {
  	const HBUINT32 *offsets = (const HBUINT32 *) loca_table->dataZ.arrayZ;
  	start_offset = offsets[gid];
  	end_offset   = offsets[gid + 1];
        }
  
        if (unlikely (start_offset > end_offset || end_offset > glyf_table.get_length ()))
  	return Glyph ();
  
        Glyph glyph (hb_bytes_t ((const char *) this->glyf_table + start_offset,
  			       end_offset - start_offset));
        return needs_padding_removal ? glyph.trim_padding () : glyph;
      }
  
      void
      add_gid_and_children (hb_codepoint_t gid, hb_set_t *gids_to_retain,
  			  unsigned int depth = 0) const
      {
        if (unlikely (depth++ > HB_MAX_NESTING_LEVEL)) return;
        /* Check if is already visited */
        if (gids_to_retain->has (gid)) return;
  
        gids_to_retain->add (gid);
  
        for (auto &item : glyph_for_gid (gid).get_composite_iterator ())
          add_gid_and_children (item.glyphIndex, gids_to_retain, depth);
      }
  
      private:
      bool short_offset;
      unsigned int num_glyphs;
      hb_blob_ptr_t<loca> loca_table;
      hb_blob_ptr_t<glyf> glyf_table;
      hb_face_t *face;
    };
  
    struct SubsetGlyph
    {
      hb_codepoint_t new_gid;
      hb_codepoint_t old_gid;
      Glyph source_glyph;
      hb_bytes_t dest_start;  /* region of source_glyph to copy first */
      hb_bytes_t dest_end;    /* region of source_glyph to copy second */
  
      bool serialize (hb_serialize_context_t *c,
  		    const hb_subset_plan_t *plan) const
      {
        TRACE_SERIALIZE (this);
  
        hb_bytes_t dest_glyph = dest_start.copy (c);
        dest_glyph = hb_bytes_t (&dest_glyph, dest_glyph.length + dest_end.copy (c).length);
        unsigned int pad_length = padding ();
        DEBUG_MSG (SUBSET, nullptr, "serialize %d byte glyph, width %d pad %d", dest_glyph.length, dest_glyph.length  + pad_length, pad_length);
  
        HBUINT8 pad;
        pad = 0;
        while (pad_length > 0)
        {
  	c->embed (pad);
  	pad_length--;
        }
  
        if (!unlikely (dest_glyph.length)) return_trace (true);
  
        /* update components gids */
        for (auto &_ : Glyph (dest_glyph).get_composite_iterator ())
        {
  	hb_codepoint_t new_gid;
  	if (plan->new_gid_for_old_gid (_.glyphIndex, &new_gid))
  	  ((OT::glyf::CompositeGlyphChain *) &_)->glyphIndex = new_gid;
        }
  
        if (plan->drop_hints) Glyph (dest_glyph).drop_hints ();
  
        return_trace (true);
      }
  
      void drop_hints_bytes ()
      { source_glyph.drop_hints_bytes (dest_start, dest_end); }
  
      unsigned int      length () const { return dest_start.length + dest_end.length; }
      /* pad to 2 to ensure 2-byte loca will be ok */
      unsigned int     padding () const { return length () % 2; }
      unsigned int padded_size () const { return length () + padding (); }
    };
  
    protected:
    UnsizedArrayOf<HBUINT8>
  		dataZ;	/* Glyphs data. */
    public:
    DEFINE_SIZE_MIN (0);	/* In reality, this is UNBOUNDED() type; but since we always
  			 * check the size externally, allow Null() object of it by
  			 * defining it _MIN instead. */
  };
  
  struct glyf_accelerator_t : glyf::accelerator_t {};
  
  } /* namespace OT */
  
  
  #endif /* HB_OT_GLYF_TABLE_HH */
  

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