/*

 * Copyright © 2014  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_CMAP_TABLE_HH

#define HB_OT_CMAP_TABLE_HH

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

#include "hb-subset-plan.hh"

struct CmapSubtableFormat0

{

  inline bool get_glyph (hb_codepoint_t codepoint, hb_codepoint_t *glyph) const

  {

    hb_codepoint_t gid = codepoint < 256 ? glyphIdArray[codepoint] : 0;

    if (!gid)

      return false;

    *glyph = gid;

    return true;

  }

  inline bool sanitize (hb_sanitize_context_t *c) const

  {

    TRACE_SANITIZE (this);

    return_trace (c->check_struct (this));

  }

  protected:

  HBUINT16      format;         /* Format number is set to 0. */

  HBUINT8       glyphIdArray[256];/* An array that maps character

                                 * code to glyph index values. */

  public:

  DEFINE_SIZE_STATIC (6 + 256);

};

struct CmapSubtableFormat4

{

  struct accelerator_t

  {

    inline void init (const CmapSubtableFormat4 *subtable)

    {

      segCount = subtable->segCountX2 / 2;

      endCount = subtable->values;

      startCount = endCount + segCount + 1;

      idDelta = startCount + segCount;

      idRangeOffset = idDelta + segCount;

      glyphIdArray = idRangeOffset + segCount;

      glyphIdArrayLength = (subtable->length - 16 - 8 * segCount) / 2;

    }

    static inline bool get_glyph_func (const void *obj, hb_codepoint_t codepoint, hb_codepoint_t *glyph)

    {

      const accelerator_t *thiz = (const accelerator_t *) obj;

      /* Custom two-array bsearch. */

      int min = 0, max = (int) thiz->segCount - 1;

      const HBUINT16 *startCount = thiz->startCount;

      const HBUINT16 *endCount = thiz->endCount;

      unsigned int i;

      while (min <= max)

      {

        int mid = (min + max) / 2;

        if (codepoint < startCount[mid])

          max = mid - 1;

        else if (codepoint > endCount[mid])

          min = mid + 1;

        else

        {

          i = mid;

          goto found;

        }

      }

      return false;

    found:

      hb_codepoint_t gid;

      unsigned int rangeOffset = thiz->idRangeOffset[i];

      if (rangeOffset == 0)

        gid = codepoint + thiz->idDelta[i];

      else

      {

        /* Somebody has been smoking... */

        unsigned int index = rangeOffset / 2 + (codepoint - thiz->startCount[i]) + i - thiz->segCount;

        if (unlikely (index >= thiz->glyphIdArrayLength))

          return false;

        gid = thiz->glyphIdArray[index];

        if (unlikely (!gid))

          return false;

        gid += thiz->idDelta[i];

      }

      *glyph = gid & 0xFFFFu;

      return true;

    }

    const HBUINT16 *endCount;

    const HBUINT16 *startCount;

    const HBUINT16 *idDelta;

    const HBUINT16 *idRangeOffset;

    const HBUINT16 *glyphIdArray;

    unsigned int segCount;

    unsigned int glyphIdArrayLength;

  };

  inline bool get_glyph (hb_codepoint_t codepoint, hb_codepoint_t *glyph) const

  {

    accelerator_t accel;

    accel.init (this);

    return accel.get_glyph_func (&accel, codepoint, glyph);

  }

  inline bool sanitize (hb_sanitize_context_t *c) const

  {

    TRACE_SANITIZE (this);

    if (unlikely (!c->check_struct (this)))

      return_trace (false);

    if (unlikely (!c->check_range (this, length)))

    {

      /* Some broken fonts have too long of a "length" value.

       * If that is the case, just change the value to truncate

       * the subtable at the end of the blob. */

      uint16_t new_length = (uint16_t) MIN ((uintptr_t) 65535,

                                            (uintptr_t) (c->end -

                                                         (char *) this));

      if (!c->try_set (&length, new_length))

        return_trace (false);

    }

    return_trace (16 + 4 * (unsigned int) segCountX2 <= length);

  }

  protected:

  HBUINT16      format;         /* Format number is set to 4. */

  HBUINT16      length;         /* This is the length in bytes of the

                                 * subtable. */

  HBUINT16      segCountX2;     /* 2 x segCount. */

  HBUINT16      values[VAR];

#if 0

  HBUINT16      endCount[segCount];     /* End characterCode for each segment,

                                         * last=0xFFFFu. */

  HBUINT16      reservedPad;            /* Set to 0. */

  HBUINT16      startCount[segCount];   /* Start character code for each segment. */

  HBINT16               idDelta[segCount];      /* Delta for all character codes in segment. */

  HBUINT16      idRangeOffset[segCount];/* Offsets into glyphIdArray or 0 */

  HBUINT16      glyphIdArray[VAR];      /* Glyph index array (arbitrary length) */

#endif

  public:

  DEFINE_SIZE_ARRAY (14, values);

};

struct CmapSubtableLongGroup

{

  friend struct CmapSubtableFormat12;

  friend struct CmapSubtableFormat13;

  friend struct cmap;

  int cmp (hb_codepoint_t codepoint) const

  {

    if (codepoint < startCharCode) return -1;

    if (codepoint > endCharCode)   return +1;

    return 0;

  }

  inline bool sanitize (hb_sanitize_context_t *c) const

  {

    TRACE_SANITIZE (this);

    return_trace (c->check_struct (this));

  }

  private:

  HBUINT32              startCharCode;  /* First character code in this group. */

  HBUINT32              endCharCode;    /* Last character code in this group. */

  HBUINT32              glyphID;        /* Glyph index; interpretation depends on

                                 * subtable format. */

  public:

  DEFINE_SIZE_STATIC (12);

};

template <typename UINT>

struct CmapSubtableTrimmed

{

  inline bool get_glyph (hb_codepoint_t codepoint, hb_codepoint_t *glyph) const

  {

    /* Rely on our implicit array bound-checking. */

    hb_codepoint_t gid = glyphIdArray[codepoint - startCharCode];

    if (!gid)

      return false;

    *glyph = gid;

    return true;

  }

  inline bool sanitize (hb_sanitize_context_t *c) const

  {

    TRACE_SANITIZE (this);

    return_trace (c->check_struct (this) && glyphIdArray.sanitize (c));

  }

  protected:

  UINT          formatReserved; /* Subtable format and (maybe) padding. */

  UINT          startCharCode;  /* First character code covered. */

  ArrayOf<GlyphID, UINT>

                glyphIdArray;   /* Array of glyph index values for character

                                 * codes in the range. */

  public:

  DEFINE_SIZE_ARRAY (5 * sizeof (UINT), glyphIdArray);

};

struct CmapSubtableFormat6  : CmapSubtableTrimmed<HBUINT16> {};

struct CmapSubtableFormat10 : CmapSubtableTrimmed<HBUINT32 > {};

template <typename T>

struct CmapSubtableLongSegmented

{

  friend struct cmap;

  inline bool get_glyph (hb_codepoint_t codepoint, hb_codepoint_t *glyph) const

  {

    int i = groups.bsearch (codepoint);

    if (i == -1)

      return false;

    *glyph = T::group_get_glyph (groups[i], codepoint);

    return true;

  }

  inline bool sanitize (hb_sanitize_context_t *c) const

  {

    TRACE_SANITIZE (this);

    return_trace (c->check_struct (this) && groups.sanitize (c));

  }

  inline bool serialize (hb_serialize_context_t *c,

  {

    TRACE_SERIALIZE (this);

    if (unlikely (!c->extend_min (*this))) return_trace (false);

    if (unlikely (!groups.serialize (c, supplier, group_data.len))) return_trace (false);

    return true;

  }

  protected:

  HBUINT16      format;         /* Subtable format; set to 12. */

  SortedArrayOf<CmapSubtableLongGroup, HBUINT32>

                groups;         /* Groupings. */

  public:

  DEFINE_SIZE_ARRAY (16, groups);

};

struct CmapSubtableFormat12 : CmapSubtableLongSegmented<CmapSubtableFormat12>

{

  static inline hb_codepoint_t group_get_glyph (const CmapSubtableLongGroup &group,

                                                hb_codepoint_t u)

  { return group.glyphID + (u - group.startCharCode); }