/*

 * 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-private.hh"

namespace OT {

struct AxisValueMap

{

  inline bool sanitize (hb_sanitize_context_t *c) const

  {

    TRACE_SANITIZE (this);

    return_trace (c->check_struct (this));

  }

  public:

  F2DOT14	fromCoord;	/* A normalized coordinate value obtained using

				 * default normalization. */

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

  public:

  DEFINE_SIZE_STATIC (4);

};

struct SegmentMaps : ArrayOf<AxisValueMap>

{

  inline int map (int value) const

  {

    /* 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 - array[0].fromCoord + array[0].toCoord;

    }

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

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

    unsigned int i;

    unsigned int count = len;

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

      ;

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

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

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

      return array[i-1].toCoord;

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

    return array[i-1].toCoord +

	   ((array[i].toCoord - array[i-1].toCoord) *

	    (value - array[i-1].fromCoord) + denom/2) / denom;

  }

  DEFINE_SIZE_ARRAY (2, array);

};

/*

 * avar — Axis Variations Table

 */

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

struct avar

{

  static const hb_tag_t tableTag	= HB_OT_TAG_avar;

  inline bool sanitize (hb_sanitize_context_t *c) const

  {

    TRACE_SANITIZE (this);

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

		    version.major == 1 &&

		    c->check_struct (this))))

      return_trace (false);

    const SegmentMaps *map = &axisSegmentMapsZ;

    unsigned int count = axisCount;

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

    {

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

        return_trace (false);

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

    }

    return_trace (true);

  }

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

  {

    unsigned int count = MIN<unsigned int> (coords_length, axisCount);

    const SegmentMaps *map = &axisSegmentMapsZ;

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

    {

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

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

    }

  }

  protected:

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

				 * initially set to 0x00010000u */

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

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

				 * must be the same number as axisCount in the

				 * 'fvar' table. */

  SegmentMaps	axisSegmentMapsZ;

  public:

  DEFINE_SIZE_MIN (8);

};

} /* namespace OT */

#endif /* HB_OT_VAR_AVAR_TABLE_HH */