/*

 * 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_FVAR_TABLE_HH

#define HB_OT_VAR_FVAR_TABLE_HH

#include "hb-open-type-private.hh"

namespace OT {

struct InstanceRecord

{

  inline bool sanitize (hb_sanitize_context_t *c, unsigned int axis_count) const

  {

    TRACE_SANITIZE (this);

    return_trace (c->check_struct (this) &&

		  c->check_array (coordinates, coordinates[0].static_size, axis_count));

  }

  protected:

  USHORT	subfamilyNameID;/* The name ID for entries in the 'name' table

				 * that provide subfamily names for this instance. */

  USHORT	reserved;	/* Reserved for future use — set to 0. */

  Fixed		coordinates[VAR];/* The coordinates array for this instance. */

  //USHORT	postScriptNameIDX;/*Optional. The name ID for entries in the 'name'

  //				  * table that provide PostScript names for this

  //				  * instance. */

  public:

  DEFINE_SIZE_ARRAY (4, coordinates);

};

struct AxisRecord

{

  inline bool sanitize (hb_sanitize_context_t *c) const

  {

    TRACE_SANITIZE (this);

    return_trace (c->check_struct (this));

  }

  public:

  Tag		axisTag;	/* Tag identifying the design variation for the axis. */

  Fixed		minValue;	/* The minimum coordinate value for the axis. */

  Fixed		defaultValue;	/* The default coordinate value for the axis. */

  Fixed		maxValue;	/* The maximum coordinate value for the axis. */

  USHORT	reserved;	/* Reserved for future use — set to 0. */

  USHORT	axisNameID;	/* The name ID for entries in the 'name' table that

				 * provide a display name for this axis. */

  public:

  DEFINE_SIZE_STATIC (20);

};

/*

 * fvar — Font Variations Table

 */

#define HB_OT_TAG_fvar HB_TAG('f','v','a','r')

struct fvar

{

  static const hb_tag_t tableTag	= HB_OT_TAG_fvar;

  inline bool sanitize (hb_sanitize_context_t *c) const

  {

    TRACE_SANITIZE (this);

    return_trace (version.sanitize (c) &&

		  likely (version.major == 1) &&

		  c->check_struct (this) &&

		  instanceSize >= axisCount * 4 + 4 &&

		  axisSize <= 1024 && /* Arbitrary, just to simplify overflow checks. */

		  instanceSize <= 1024 && /* Arbitrary, just to simplify overflow checks. */

		  c->check_range (this, things) &&

		  c->check_range (&StructAtOffset<char> (this, things),

				  axisCount * axisSize + instanceCount * instanceSize));

  }

  inline unsigned int get_axis_count (void) const

  { return axisCount; }

  inline bool get_axis (unsigned int index, hb_ot_var_axis_t *info) const

  {

    if (unlikely (index >= axisCount))

      return false;

    if (info)

    {

      const AxisRecord &axis = get_axes ()[index];

      info->tag = axis.axisTag;

      info->name_id =  axis.axisNameID;

      info->default_value = axis.defaultValue / 65536.;

      /* Ensure order, to simplify client math. */

      info->min_value = MIN<float> (info->default_value, axis.minValue / 65536.);

      info->max_value = MAX<float> (info->default_value, axis.maxValue / 65536.);

    }

    return true;

  }

  inline unsigned int get_axis_infos (unsigned int      start_offset,

				      unsigned int     *axes_count /* IN/OUT */,

				      hb_ot_var_axis_t *axes_array /* OUT */) const

  {

    if (axes_count)

    {

      unsigned int count = axisCount;

      start_offset = MIN (start_offset, count);

      count -= start_offset;

      axes_array += start_offset;

      count = MIN (count, *axes_count);

      *axes_count = count;

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

	get_axis (start_offset + i, axes_array + i);

    }

    return axisCount;

  }

  inline bool find_axis (hb_tag_t tag, unsigned int *index, hb_ot_var_axis_t *info) const

  {

    const AxisRecord *axes = get_axes ();

    unsigned int count = get_axis_count ();

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

      if (axes[i].axisTag == tag)

      {

        if (index)

	  *index = i;

	return get_axis (i, info);

      }

    if (index)

      *index = HB_OT_VAR_NO_AXIS_INDEX;

    return false;

  }

  inline int normalize_axis_value (unsigned int axis_index, float v) const

  {

    hb_ot_var_axis_t axis;

    if (!get_axis (axis_index, &axis))

      return 0;

    v = MAX (MIN (v, axis.max_value), axis.min_value); /* Clamp. */

    if (v == axis.default_value)

      return 0;

    else if (v < axis.default_value)

      v = (v - axis.default_value) / (axis.default_value - axis.min_value);

    else

      v = (v - axis.default_value) / (axis.max_value - axis.default_value);

    return (int) (v * 16384. + (v >= 0. ? .5 : -.5));

  }

  protected:

  inline const AxisRecord * get_axes (void) const

  { return &StructAtOffset<AxisRecord> (this, things); }

  inline const InstanceRecord * get_instances (void) const

  { return &StructAtOffset<InstanceRecord> (get_axes () + axisCount, 0); }

  protected:

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

				 * initially set to 0x00010000u */

  Offset<>	things;		/* Offset in bytes from the beginning of the table

				 * to the start of the AxisRecord array. */

  USHORT	reserved;	/* This field is permanently reserved. Set to 2. */

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

				 * number of records in the axes array). */

  USHORT	axisSize;	/* The size in bytes of each VariationAxisRecord —

				 * set to 20 (0x0014) for this version. */

  USHORT	instanceCount;	/* The number of named instances defined in the font

				 * (the number of records in the instances array). */

  USHORT	instanceSize;	/* The size in bytes of each InstanceRecord — set

				 * to either axisCount * sizeof(Fixed) + 4, or to

				 * axisCount * sizeof(Fixed) + 6. */

  public:

  DEFINE_SIZE_STATIC (16);

};

} /* namespace OT */

#endif /* HB_OT_VAR_FVAR_TABLE_HH */