/*

 * 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.

 *

 * Adobe Author(s): Michiharu Ariza

 */

#ifndef HB_OT_VAR_GVAR_TABLE_HH

#define HB_OT_VAR_GVAR_TABLE_HH

#include "hb-open-type.hh"

/*

 * gvar -- Glyph Variation Table

 * https://docs.microsoft.com/en-us/typography/opentype/spec/gvar

 */

#define HB_OT_TAG_gvar HB_TAG('g','v','a','r')

namespace OT {

struct contour_point_t

{

  void init (float x_ = 0.f, float y_ = 0.f, bool is_end_point_ = false)

  { flag = 0; x = x_; y = y_; is_end_point = is_end_point_; }

  void translate (const contour_point_t &p) { x += p.x; y += p.y; }

  float x = 0.f;

  float y = 0.f;

  uint8_t flag = 0;

  bool is_end_point = false;

};

struct contour_point_vector_t : hb_vector_t<contour_point_t>

{

  void extend (const hb_array_t<contour_point_t> &a)

  {

    unsigned int old_len = length;

    if (unlikely (!resize (old_len + a.length)))

      return;

    auto arrayZ = this->arrayZ + old_len;

    unsigned count = a.length;

    for (unsigned int i = 0; i < count; i++)

      arrayZ[i] = a.arrayZ[i];

  }

  void transform (const float (&matrix)[4])

  {

    if (matrix[0] == 1.f && matrix[1] == 0.f &&

  matrix[2] == 0.f && matrix[3] == 1.f)

      return;

    auto arrayZ = this->arrayZ;

    unsigned count = length;

    for (unsigned i = 0; i < count; i++)

    {

      contour_point_t &p = arrayZ[i];

      float x_ = p.x * matrix[0] + p.y * matrix[2];

     p.y = p.x * matrix[1] + p.y * matrix[3];

      p.x = x_;

    }

  }

  void translate (const contour_point_t& delta)

  {

    if (delta.x == 0.f && delta.y == 0.f)

      return;

    auto arrayZ = this->arrayZ;

    unsigned count = length;

    for (unsigned i = 0; i < count; i++)

      arrayZ[i].translate (delta);

  }

};

/* https://docs.microsoft.com/en-us/typography/opentype/spec/otvarcommonformats#tuplevariationheader */

struct TupleVariationHeader

{

  unsigned get_size (unsigned axis_count) const

  { return min_size + get_all_tuples (axis_count).get_size (); }

  unsigned get_data_size () const { return varDataSize; }

  const TupleVariationHeader &get_next (unsigned axis_count) const

  { return StructAtOffset<TupleVariationHeader> (this, get_size (axis_count)); }

  float calculate_scalar (hb_array_t<int> coords, unsigned int coord_count,

        const hb_array_t<const F2DOT14> shared_tuples) const

  {

    hb_array_t<const F2DOT14> peak_tuple;

    if (has_peak ())

      peak_tuple = get_peak_tuple (coord_count);

    else

    {

      unsigned int index = get_index ();

      if (unlikely (index * coord_count >= shared_tuples.length))

  return 0.f;

      peak_tuple = shared_tuples.sub_array (coord_count * index, coord_count);

    }

    hb_array_t<const F2DOT14> start_tuple;

    hb_array_t<const F2DOT14> end_tuple;

    if (has_intermediate ())

    {

      start_tuple = get_start_tuple (coord_count);

      end_tuple = get_end_tuple (coord_count);

    }

    float scalar = 1.f;

    for (unsigned int i = 0; i < coord_count; i++)

    {

      int v = coords[i];

      int peak = peak_tuple[i];

      if (!peak || v == peak) continue;

      if (has_intermediate ())

      {

  int start = start_tuple[i];

  int end = end_tuple[i];

  if (unlikely (start > peak || peak > end ||

          (start < 0 && end > 0 && peak))) continue;

  if (v < start || v > end) return 0.f;

  if (v < peak)

  { if (peak != start) scalar *= (float) (v - start) / (peak - start); }

  else

  { if (peak != end) scalar *= (float) (end - v) / (end - peak); }

      }

      else if (!v || v < hb_min (0, peak) || v > hb_max (0, peak)) return 0.f;

      else

  scalar *= (float) v / peak;

    }

    return scalar;

  }

  bool           has_peak () const { return tupleIndex & TuppleIndex::EmbeddedPeakTuple; }

  bool   has_intermediate () const { return tupleIndex & TuppleIndex::IntermediateRegion; }

  bool has_private_points () const { return tupleIndex & TuppleIndex::PrivatePointNumbers; }

  unsigned      get_index () const { return tupleIndex & TuppleIndex::TupleIndexMask; }

  protected:

  struct TuppleIndex : HBUINT16

  {

    enum Flags {

      EmbeddedPeakTuple   = 0x8000u,

      IntermediateRegion  = 0x4000u,

      PrivatePointNumbers = 0x2000u,

      TupleIndexMask      = 0x0FFFu

    };

    DEFINE_SIZE_STATIC (2);

  };

  hb_array_t<const F2DOT14> get_all_tuples (unsigned axis_count) const

  { return StructAfter<UnsizedArrayOf<F2DOT14>> (tupleIndex).as_array ((has_peak () + has_intermediate () * 2) * axis_count); }

  hb_array_t<const F2DOT14> get_peak_tuple (unsigned axis_count) const

  { return get_all_tuples (axis_count).sub_array (0, axis_count); }

  hb_array_t<const F2DOT14> get_start_tuple (unsigned axis_count) const

  { return get_all_tuples (axis_count).sub_array (has_peak () * axis_count, axis_count); }

  hb_array_t<const F2DOT14> get_end_tuple (unsigned axis_count) const

  { return get_all_tuples (axis_count).sub_array (has_peak () * axis_count + axis_count, axis_count); }

  HBUINT16  varDataSize;  /* The size in bytes of the serialized

         * data for this tuple variation table. */

  TuppleIndex tupleIndex; /* A packed field. The high 4 bits are flags (see below).

           The low 12 bits are an index into a shared tuple

           records array. */

  /* UnsizedArrayOf<F2DOT14> peakTuple - optional */

        /* Peak tuple record for this tuple variation table — optional,

         * determined by flags in the tupleIndex value.

         *

         * Note that this must always be included in the 'cvar' table. */

  /* UnsizedArrayOf<F2DOT14> intermediateStartTuple - optional */

        /* Intermediate start tuple record for this tuple variation table — optional,

           determined by flags in the tupleIndex value. */

  /* UnsizedArrayOf<F2DOT14> intermediateEndTuple - optional */

        /* Intermediate end tuple record for this tuple variation table — optional,

         * determined by flags in the tupleIndex value. */

  public:

  DEFINE_SIZE_MIN (4);

};

struct GlyphVariationData

{

  const TupleVariationHeader &get_tuple_var_header (void) const

  { return StructAfter<TupleVariationHeader> (data); }

  struct tuple_iterator_t

  {

    void init (hb_bytes_t var_data_bytes_, unsigned int axis_count_)

    {

      var_data_bytes = var_data_bytes_;

      var_data = var_data_bytes_.as<GlyphVariationData> ();

      index = 0;

      axis_count = axis_count_;

      current_tuple = &var_data->get_tuple_var_header ();

      data_offset = 0;

    }

    bool get_shared_indices (hb_vector_t<unsigned int> &shared_indices /* OUT */)

    {

      if (var_data->has_shared_point_numbers ())

      {

  const HBUINT8 *base = &(var_data+var_data->data);

  const HBUINT8 *p = base;

  if (!unpack_points (p, shared_indices, (const HBUINT8 *) (var_data_bytes.arrayZ + var_data_bytes.length))) return false;

  data_offset = p - base;

      }

      return true;

    }

    bool is_valid () const

    {

      return (index < var_data->tupleVarCount.get_count ()) &&

       var_data_bytes.check_range (current_tuple, TupleVariationHeader::min_size) &&

       var_data_bytes.check_range (current_tuple, hb_max (current_tuple->get_data_size (), current_tuple->get_size (axis_count))) &&

       current_tuple->get_size (axis_count);

    }

    bool move_to_next ()

    {

      data_offset += current_tuple->get_data_size ();

      current_tuple = &current_tuple->get_next (axis_count);

      index++;

      return is_valid ();

    }

    const HBUINT8 *get_serialized_data () const

    { return &(var_data+var_data->data) + data_offset; }

    private:

    const GlyphVariationData *var_data;

    unsigned int index;

    unsigned int axis_count;

    unsigned int data_offset;

    public:

    hb_bytes_t var_data_bytes;

    const TupleVariationHeader *current_tuple;

  };

  static bool get_tuple_iterator (hb_bytes_t var_data_bytes, unsigned axis_count,

          hb_vector_t<unsigned int> &shared_indices /* OUT */,

          tuple_iterator_t *iterator /* OUT */)

  {

    iterator->init (var_data_bytes, axis_count);

    if (!iterator->get_shared_indices (shared_indices))

      return false;

    return iterator->is_valid ();

  }

  bool has_shared_point_numbers () const { return tupleVarCount.has_shared_point_numbers (); }

  static bool unpack_points (const HBUINT8 *&p /* IN/OUT */,

           hb_vector_t<unsigned int> &points /* OUT */,

           const HBUINT8 *end)

  {

    enum packed_point_flag_t

    {

      POINTS_ARE_WORDS     = 0x80,

      POINT_RUN_COUNT_MASK = 0x7F

    };

    if (unlikely (p + 1 > end)) return false;

    uint16_t count = *p++;

    if (count & POINTS_ARE_WORDS)

    {

      if (unlikely (p + 1 > end)) return false;

      count = ((count & POINT_RUN_COUNT_MASK) << 8) | *p++;

    }

    if (unlikely (!points.resize (count))) return false;

    unsigned int n = 0;

    uint16_t i = 0;

    while (i < count)

    {

      if (unlikely (p + 1 > end)) return false;

      uint16_t j;

      uint8_t control = *p++;

      uint16_t run_count = (control & POINT_RUN_COUNT_MASK) + 1;

      if (control & POINTS_ARE_WORDS)

      {

  for (j = 0; j < run_count && i < count; j++, i++)

  {

    if (unlikely (p + HBUINT16::static_size > end)) return false;

    n += *(const HBUINT16 *)p;

    points[i] = n;

    p += HBUINT16::static_size;

  }

      }

      else

      {

  for (j = 0; j < run_count && i < count; j++, i++)

  {

    if (unlikely (p + 1 > end)) return false;

    n += *p++;

    points[i] = n;

  }

      }

      if (j < run_count) return false;

    }

    return true;

  }

  static bool unpack_deltas (const HBUINT8 *&p /* IN/OUT */,

           hb_vector_t<int> &deltas /* IN/OUT */,

           const HBUINT8 *end)

  {

    enum packed_delta_flag_t

    {

      DELTAS_ARE_ZERO      = 0x80,

      DELTAS_ARE_WORDS     = 0x40,

      DELTA_RUN_COUNT_MASK = 0x3F

    };

    unsigned int i = 0;

    unsigned int count = deltas.length;

    while (i < count)

    {

      if (unlikely (p + 1 > end)) return false;

      uint8_t control = *p++;

      unsigned int run_count = (control & DELTA_RUN_COUNT_MASK) + 1;

      unsigned int j;

      if (control & DELTAS_ARE_ZERO)

  for (j = 0; j < run_count && i < count; j++, i++)

    deltas[i] = 0;

      else if (control & DELTAS_ARE_WORDS)

  for (j = 0; j < run_count && i < count; j++, i++)

  {

    if (unlikely (p + HBUINT16::static_size > end)) return false;

    deltas[i] = *(const HBINT16 *) p;

    p += HBUINT16::static_size;

  }

      else

  for (j = 0; j < run_count && i < count; j++, i++)

  {

    if (unlikely (p + 1 > end)) return false;

    deltas[i] = *(const HBINT8 *) p++;

  }

      if (j < run_count)

  return false;

    }

    return true;

  }

  bool has_data () const { return tupleVarCount; }

  protected:

  struct TupleVarCount : HBUINT16

  {

    bool has_shared_point_numbers () const { return ((*this) & SharedPointNumbers); }

    unsigned int get_count () const { return (*this) & CountMask; }

    protected:

    enum Flags

    {

      SharedPointNumbers= 0x8000u,

      CountMask   = 0x0FFFu

    };

    public:

    DEFINE_SIZE_STATIC (2);

  };

  TupleVarCount tupleVarCount;  /* A packed field. The high 4 bits are flags, and the

         * low 12 bits are the number of tuple variation tables

         * for this glyph. The number of tuple variation tables

         * can be any number between 1 and 4095. */

  Offset16To<HBUINT8>

    data;   /* Offset from the start of the GlyphVariationData table

         * to the serialized data. */

  /* TupleVariationHeader tupleVariationHeaders[] *//* Array of tuple variation headers. */

  public:

  DEFINE_SIZE_MIN (4);

};

struct gvar

{

  static constexpr hb_tag_t tableTag = HB_OT_TAG_gvar;

  bool sanitize_shallow (hb_sanitize_context_t *c) const

  {

    TRACE_SANITIZE (this);

    return_trace (c->check_struct (this) && (version.major == 1) &&

      sharedTuples.sanitize (c, this, axisCount * sharedTupleCount) &&

      (is_long_offset () ?

         c->check_array (get_long_offset_array (), glyphCount+1) :

         c->check_array (get_short_offset_array (), glyphCount+1)));

  }

  /* GlyphVariationData not sanitized here; must be checked while accessing each glyph variation data */

  bool sanitize (hb_sanitize_context_t *c) const

  { return sanitize_shallow (c); }

  bool subset (hb_subset_context_t *c) const

  {

    TRACE_SUBSET (this);

    gvar *out = c->serializer->allocate_min<gvar> ();

    if (unlikely (!out)) return_trace (false);

    out->version.major = 1;

    out->version.minor = 0;

    out->axisCount = axisCount;

    out->sharedTupleCount = sharedTupleCount;

    unsigned int num_glyphs = c->plan->num_output_glyphs ();

    out->glyphCount = num_glyphs;

    unsigned int subset_data_size = 0;

    for (hb_codepoint_t gid = (c->plan->flags & HB_SUBSET_FLAGS_NOTDEF_OUTLINE) ? 0 : 1;

         gid < num_glyphs;

         gid++)

    {

      hb_codepoint_t old_gid;

      if (!c->plan->old_gid_for_new_gid (gid, &old_gid)) continue;

      subset_data_size += get_glyph_var_data_bytes (c->source_blob, old_gid).length;

    }

    bool long_offset = subset_data_size & ~0xFFFFu;

    out->flags = long_offset ? 1 : 0;

    HBUINT8 *subset_offsets = c->serializer->allocate_size<HBUINT8> ((long_offset ? 4 : 2) * (num_glyphs + 1));

    if (!subset_offsets) return_trace (false);

    /* shared tuples */

    if (!sharedTupleCount || !sharedTuples)

      out->sharedTuples = 0;

    else

    {

      unsigned int shared_tuple_size = F2DOT14::static_size * axisCount * sharedTupleCount;

      F2DOT14 *tuples = c->serializer->allocate_size<F2DOT14> (shared_tuple_size);

      if (!tuples) return_trace (false);

      out->sharedTuples = (char *) tuples - (char *) out;

      memcpy (tuples, this+sharedTuples, shared_tuple_size);

    }

    char *subset_data = c->serializer->allocate_size<char> (subset_data_size);

    if (!subset_data) return_trace (false);

    out->dataZ = subset_data - (char *) out;

    unsigned int glyph_offset = 0;

    for (hb_codepoint_t gid = (c->plan->flags & HB_SUBSET_FLAGS_NOTDEF_OUTLINE) ? 0 : 1;

         gid < num_glyphs;

         gid++)

    {

      hb_codepoint_t old_gid;

      hb_bytes_t var_data_bytes = c->plan->old_gid_for_new_gid (gid, &old_gid)

        ? get_glyph_var_data_bytes (c->source_blob, old_gid)

        : hb_bytes_t ();

      if (long_offset)

  ((HBUINT32 *) subset_offsets)[gid] = glyph_offset;

      else

  ((HBUINT16 *) subset_offsets)[gid] = glyph_offset / 2;

      if (var_data_bytes.length > 0)

  memcpy (subset_data, var_data_bytes.arrayZ, var_data_bytes.length);

      subset_data += var_data_bytes.length;

      glyph_offset += var_data_bytes.length;

    }

    if (long_offset)

      ((HBUINT32 *) subset_offsets)[num_glyphs] = glyph_offset;

    else

      ((HBUINT16 *) subset_offsets)[num_glyphs] = glyph_offset / 2;

    return_trace (true);

  }

  protected:

  const hb_bytes_t get_glyph_var_data_bytes (hb_blob_t *blob, hb_codepoint_t glyph) const

  {

    unsigned start_offset = get_offset (glyph);

    unsigned end_offset = get_offset (glyph+1);

    if (unlikely (end_offset < start_offset)) return hb_bytes_t ();

    unsigned length = end_offset - start_offset;

    hb_bytes_t var_data = blob->as_bytes ().sub_array (((unsigned) dataZ) + start_offset, length);

    return likely (var_data.length >= GlyphVariationData::min_size) ? var_data : hb_bytes_t ();

  }

  bool is_long_offset () const { return flags & 1; }

  unsigned get_offset (unsigned i) const

  {

    if (unlikely (i > glyphCount)) return 0;

    return is_long_offset () ? get_long_offset_array ()[i] : get_short_offset_array ()[i] * 2;

  }

  const HBUINT32 * get_long_offset_array () const { return (const HBUINT32 *) &offsetZ; }

  const HBUINT16 *get_short_offset_array () const { return (const HBUINT16 *) &offsetZ; }

  public:

  struct accelerator_t

  {

    accelerator_t (hb_face_t *face)

    { table = hb_sanitize_context_t ().reference_table<gvar> (face); }

    ~accelerator_t () { table.destroy (); }

    private:

    static float infer_delta (const hb_array_t<contour_point_t> points,

            const hb_array_t<contour_point_t> deltas,

            unsigned int target, unsigned int prev, unsigned int next,

            float contour_point_t::*m)

    {

      float target_val = points[target].*m;

      float prev_val = points[prev].*m;

      float next_val = points[next].*m;

      float prev_delta =  deltas[prev].*m;

      float next_delta =  deltas[next].*m;

      if (prev_val == next_val)

  return (prev_delta == next_delta) ? prev_delta : 0.f;

      else if (target_val <= hb_min (prev_val, next_val))

  return (prev_val < next_val) ? prev_delta : next_delta;

      else if (target_val >= hb_max (prev_val, next_val))

  return (prev_val > next_val) ? prev_delta : next_delta;

      /* linear interpolation */

      float r = (target_val - prev_val) / (next_val - prev_val);

      return prev_delta + r * (next_delta - prev_delta);

    }

    static unsigned int next_index (unsigned int i, unsigned int start, unsigned int end)

    { return (i >= end) ? start : (i + 1); }

    public:

    bool apply_deltas_to_points (hb_codepoint_t glyph, hb_font_t *font,

         const hb_array_t<contour_point_t> points) const

    {

      if (!font->num_coords) return true;

      if (unlikely (glyph >= table->glyphCount)) return true;

      hb_bytes_t var_data_bytes = table->get_glyph_var_data_bytes (table.get_blob (), glyph);

      if (!var_data_bytes.as<GlyphVariationData> ()->has_data ()) return true;

      hb_vector_t<unsigned int> shared_indices;

      GlyphVariationData::tuple_iterator_t iterator;

      if (!GlyphVariationData::get_tuple_iterator (var_data_bytes, table->axisCount,

               shared_indices, &iterator))

  return true; /* so isn't applied at all */

      /* Save original points for inferred delta calculation */

      contour_point_vector_t orig_points;

      if (unlikely (!orig_points.resize (points.length))) return false;

      for (unsigned int i = 0; i < orig_points.length; i++)

  orig_points.arrayZ[i] = points.arrayZ[i];

      contour_point_vector_t deltas; /* flag is used to indicate referenced point */

      if (unlikely (!deltas.resize (points.length))) return false;

      hb_vector_t<unsigned> end_points;

      for (unsigned i = 0; i < points.length; ++i)

  if (points[i].is_end_point)

    end_points.push (i);

      auto coords = hb_array (font->coords, font->num_coords);

      unsigned num_coords = table->axisCount;

      hb_array_t<const F2DOT14> shared_tuples = (table+table->sharedTuples).as_array (table->sharedTupleCount * table->axisCount);

      hb_vector_t<unsigned int> private_indices;

      hb_vector_t<int> x_deltas;

      hb_vector_t<int> y_deltas;

      do

      {

  float scalar = iterator.current_tuple->calculate_scalar (coords, num_coords, shared_tuples);

  if (scalar == 0.f) continue;

  const HBUINT8 *p = iterator.get_serialized_data ();

  unsigned int length = iterator.current_tuple->get_data_size ();

  if (unlikely (!iterator.var_data_bytes.check_range (p, length)))

    return false;

  const HBUINT8 *end = p + length;

  bool has_private_points = iterator.current_tuple->has_private_points ();

  if (has_private_points &&

      !GlyphVariationData::unpack_points (p, private_indices, end))

    return false;

  const hb_array_t<unsigned int> &indices = has_private_points ? private_indices : shared_indices;

  bool apply_to_all = (indices.length == 0);

  unsigned int num_deltas = apply_to_all ? points.length : indices.length;

  if (unlikely (!x_deltas.resize (num_deltas))) return false;

  if (unlikely (!GlyphVariationData::unpack_deltas (p, x_deltas, end))) return false;

  if (unlikely (!y_deltas.resize (num_deltas))) return false;

  if (unlikely (!GlyphVariationData::unpack_deltas (p, y_deltas, end))) return false;

  for (unsigned int i = 0; i < deltas.length; i++)

    deltas[i].init ();

  for (unsigned int i = 0; i < num_deltas; i++)

  {

    unsigned int pt_index = apply_to_all ? i : indices[i];

    if (unlikely (pt_index >= deltas.length)) continue;

    deltas.arrayZ[pt_index].flag = 1; /* this point is referenced, i.e., explicit deltas specified */

    deltas.arrayZ[pt_index].x += x_deltas.arrayZ[i] * scalar;

    deltas.arrayZ[pt_index].y += y_deltas.arrayZ[i] * scalar;

  }

  /* infer deltas for unreferenced points */

  unsigned start_point = 0;

  for (unsigned c = 0; c < end_points.length; c++)

  {

    unsigned end_point = end_points[c];

    /* Check the number of unreferenced points in a contour. If no unref points or no ref points, nothing to do. */

    unsigned unref_count = 0;

    for (unsigned i = start_point; i <= end_point; i++)

      if (!deltas[i].flag) unref_count++;

    unsigned j = start_point;

    if (unref_count == 0 || unref_count > end_point - start_point)

      goto no_more_gaps;

    for (;;)

    {

      /* Locate the next gap of unreferenced points between two referenced points prev and next.

       * Note that a gap may wrap around at left (start_point) and/or at right (end_point).

       */

      unsigned int prev, next, i;

      for (;;)

      {

        i = j;

        j = next_index (i, start_point, end_point);

        if (deltas[i].flag && !deltas[j].flag) break;

      }

      prev = j = i;

      for (;;)

      {

        i = j;

        j = next_index (i, start_point, end_point);

        if (!deltas[i].flag && deltas[j].flag) break;

      }

      next = j;

      /* Infer deltas for all unref points in the gap between prev and next */

      i = prev;

      for (;;)

      {

        i = next_index (i, start_point, end_point);

        if (i == next) break;

        deltas[i].x = infer_delta (orig_points.as_array (), deltas.as_array (), i, prev, next, &contour_point_t::x);

        deltas[i].y = infer_delta (orig_points.as_array (), deltas.as_array (), i, prev, next, &contour_point_t::y);

        if (--unref_count == 0) goto no_more_gaps;

      }

    }

  no_more_gaps:

    start_point = end_point + 1;

  }

  /* apply specified / inferred deltas to points */

  for (unsigned int i = 0; i < points.length; i++)

  {

    points.arrayZ[i].x += deltas.arrayZ[i].x;

    points.arrayZ[i].y += deltas.arrayZ[i].y;

  }

      } while (iterator.move_to_next ());

      return true;

    }

    unsigned int get_axis_count () const { return table->axisCount; }

    private:

    hb_blob_ptr_t<gvar> table;

  };

  protected:

  FixedVersion<>version;  /* Version number of the glyph variations table

         * Set to 0x00010000u. */

  HBUINT16  axisCount;  /* The number of variation axes for this font. This must be

         * the same number as axisCount in the 'fvar' table. */

  HBUINT16  sharedTupleCount;

        /* The number of shared tuple records. Shared tuple records

         * can be referenced within glyph variation data tables for

         * multiple glyphs, as opposed to other tuple records stored

         * directly within a glyph variation data table. */

  NNOffset32To<UnsizedArrayOf<F2DOT14>>

    sharedTuples; /* Offset from the start of this table to the shared tuple records.

         * Array of tuple records shared across all glyph variation data tables. */

  HBUINT16  glyphCount; /* The number of glyphs in this font. This must match the number of

         * glyphs stored elsewhere in the font. */

  HBUINT16  flags;    /* Bit-field that gives the format of the offset array that follows.

         * If bit 0 is clear, the offsets are uint16; if bit 0 is set, the

         * offsets are uint32. */

  Offset32To<GlyphVariationData>

    dataZ;    /* Offset from the start of this table to the array of

         * GlyphVariationData tables. */

  UnsizedArrayOf<HBUINT8>

    offsetZ;  /* Offsets from the start of the GlyphVariationData array

         * to each GlyphVariationData table. */

  public:

  DEFINE_SIZE_ARRAY (20, offsetZ);

};

struct gvar_accelerator_t : gvar::accelerator_t {

  gvar_accelerator_t (hb_face_t *face) : gvar::accelerator_t (face) {}

};

} /* namespace OT */

#endif /* HB_OT_VAR_GVAR_TABLE_HH */