/*

 * Copyright © 2017  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.

 *

 * Google Author(s): Behdad Esfahbod

 */

#ifndef HB_OT_VAR_AVAR_TABLE_HH

#define HB_OT_VAR_AVAR_TABLE_HH

#include "hb-open-type.hh"

#include "hb-ot-var-common.hh"

/*

 * avar -- Axis Variations

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

 */

#define HB_OT_TAG_avar HB_TAG('a','v','a','r')

namespace OT {

/* "Spec": https://github.com/be-fonts/boring-expansion-spec/issues/14 */

struct avarV2Tail

{

  friend struct avar;

  bool sanitize (hb_sanitize_context_t *c,

     const void *base) const

  {

    TRACE_SANITIZE (this);

    return_trace (varIdxMap.sanitize (c, base) &&

      varStore.sanitize (c, base));

  }

  protected:

  Offset32To<DeltaSetIndexMap>  varIdxMap;  /* Offset from the beginning of 'avar' table. */

  Offset32To<VariationStore>  varStore; /* Offset from the beginning of 'avar' table. */

  public:

  DEFINE_SIZE_STATIC (8);

};

struct AxisValueMap

{

  bool sanitize (hb_sanitize_context_t *c) const

  {

    TRACE_SANITIZE (this);

    return_trace (c->check_struct (this));

  }

  public:

  F2DOT14 coords[2];

//   F2DOT14  fromCoord;  /* A normalized coordinate value obtained using

//         * default normalization. */

//   F2DOT14  toCoord;  /* The modified, normalized coordinate value. */

  public:

  DEFINE_SIZE_STATIC (4);

};

struct SegmentMaps : Array16Of<AxisValueMap>

{

  int map (int value, unsigned int from_offset = 0, unsigned int to_offset = 1) const

  {

#define fromCoord coords[from_offset]

#define toCoord coords[to_offset]

    /* The following special-cases are not part of OpenType, which requires

     * that at least -1, 0, and +1 must be mapped. But we include these as

     * part of a better error recovery scheme. */

    if (len < 2)

    {

      if (!len)

  return value;

      else /* len == 1*/

  return value - arrayZ[0].fromCoord + arrayZ[0].toCoord;

    }

    if (value <= arrayZ[0].fromCoord)

      return value - arrayZ[0].fromCoord + arrayZ[0].toCoord;

    unsigned int i;

    unsigned int count = len - 1;

    for (i = 1; i < count && value > arrayZ[i].fromCoord; i++)

      ;

    if (value >= arrayZ[i].fromCoord)

      return value - arrayZ[i].fromCoord + arrayZ[i].toCoord;

    if (unlikely (arrayZ[i-1].fromCoord == arrayZ[i].fromCoord))

      return arrayZ[i-1].toCoord;

    int denom = arrayZ[i].fromCoord - arrayZ[i-1].fromCoord;

    return roundf (arrayZ[i-1].toCoord + ((float) (arrayZ[i].toCoord - arrayZ[i-1].toCoord) *

            (value - arrayZ[i-1].fromCoord)) / denom);

#undef toCoord

#undef fromCoord

  }

  int unmap (int value) const { return map (value, 1, 0); }

  public:

  DEFINE_SIZE_ARRAY (2, *this);

};

struct avar

{

  static constexpr hb_tag_t tableTag = HB_OT_TAG_avar;

  bool has_data () const { return version.to_int (); }

  const SegmentMaps* get_segment_maps () const

  { return &firstAxisSegmentMaps; }

  unsigned get_axis_count () const

  { return axisCount; }

  bool sanitize (hb_sanitize_context_t *c) const

  {

    TRACE_SANITIZE (this);

    if (!(version.sanitize (c) &&

    (version.major == 1

#ifndef HB_NO_VARIATIONS2

     || version.major == 2

#endif

     ) &&

    c->check_struct (this)))

      return_trace (false);

    const SegmentMaps *map = &firstAxisSegmentMaps;

    unsigned int count = axisCount;

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

    {

      if (unlikely (!map->sanitize (c)))

  return_trace (false);

      map = &StructAfter<SegmentMaps> (*map);

    }

#ifndef HB_NO_VARIATIONS2

    if (version.major == 2)

    {

      const auto *v2 = (const avarV2Tail *) map;

      if (unlikely (!v2->sanitize (c, this)))

  return_trace (false);

    }

#endif

    return_trace (true);

  }

  void map_coords (int *coords, unsigned int coords_length) const

  {

    unsigned int count = hb_min (coords_length, axisCount);

    const SegmentMaps *map = &firstAxisSegmentMaps;

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

    {

      coords[i] = map->map (coords[i]);

      map = &StructAfter<SegmentMaps> (*map);

    }

#ifndef HB_NO_VARIATIONS2

    if (version.major < 2)

      return;

    const auto *v2 = (const avarV2Tail *) map;

    const auto &varidx_map = this+v2->varIdxMap;

    const auto &var_store = this+v2->varStore;

    auto *var_store_cache = var_store.create_cache ();

    hb_vector_t<int> out;

    out.alloc (coords_length);

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

    {

      int v = coords[i];

      uint32_t varidx = varidx_map.map (i);

      float delta = var_store.get_delta (varidx, coords, coords_length, var_store_cache);

      v += roundf (delta);

      v = hb_clamp (v, -(1<<14), +(1<<14));

      out.push (v);

    }

    OT::VariationStore::destroy_cache (var_store_cache);

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

      coords[i] = out[i];

#endif

  }

  void unmap_coords (int *coords, unsigned int coords_length) const

  {

    unsigned int count = hb_min (coords_length, axisCount);

    const SegmentMaps *map = &firstAxisSegmentMaps;

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

    {

      coords[i] = map->unmap (coords[i]);

      map = &StructAfter<SegmentMaps> (*map);

    }

  }

  protected:

  FixedVersion<>version;  /* Version of the avar table

         * initially set to 0x00010000u */

  HBUINT16  reserved; /* This field is permanently reserved. Set to 0. */

  HBUINT16  axisCount;  /* The number of variation axes in the font. This

         * must be the same number as axisCount in the

         * 'fvar' table. */

  SegmentMaps firstAxisSegmentMaps;

  public:

  DEFINE_SIZE_MIN (8);

};

} /* namespace OT */

#endif /* HB_OT_VAR_AVAR_TABLE_HH */