kc3-lang/harfbuzz/src/hb-ot-cmap-table.hh

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• Hash : 251cc977
  Author :
  Date : 2018-05-30T12:23:51
  

  [subset] Switch to using hb_map_t inside of hb_subset_plan_t.
  

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• src/hb-ot-cmap-table.hh

• /*
   * 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-set-private.hh"
  #include "hb-subset-plan.hh"
  
  /*
   * cmap -- Character to Glyph Index Mapping
   * https://docs.microsoft.com/en-us/typography/opentype/spec/cmap
   */
  #define HB_OT_TAG_cmap HB_TAG('c','m','a','p')
  
  
  namespace OT {
  
  
  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. */
    HBUINT16	length;		/* Byte length of this subtable. */
    HBUINT16	language;	/* Ignore. */
    HBUINT8	glyphIdArray[256];/* An array that maps character
  				 * code to glyph index values. */
    public:
    DEFINE_SIZE_STATIC (6 + 256);
  };
  
  struct CmapSubtableFormat4
  {
    struct segment_plan
    {
      HBUINT16 start_code;
      HBUINT16 end_code;
      bool use_delta;
    };
  
    bool serialize (hb_serialize_context_t *c,
                    const hb_subset_plan_t *plan,
                    const hb_vector_t<segment_plan> &segments)
    {
      TRACE_SERIALIZE (this);
  
      if (unlikely (!c->extend_min (*this))) return_trace (false);
  
      this->format.set (4);
      this->length.set (get_sub_table_size (segments));
  
      this->segCountX2.set (segments.len * 2);
      this->entrySelector.set (MAX (1u, _hb_bit_storage (segments.len)) - 1);
      this->searchRange.set (2 * (1u << this->entrySelector));
      this->rangeShift.set (segments.len * 2 > this->searchRange
                            ? 2 * segments.len - this->searchRange
                            : 0);
  
      HBUINT16 *end_count = c->allocate_size<HBUINT16> (HBUINT16::static_size * segments.len);
      c->allocate_size<HBUINT16> (HBUINT16::static_size); // 2 bytes of padding.
      HBUINT16 *start_count = c->allocate_size<HBUINT16> (HBUINT16::static_size * segments.len);
      HBINT16 *id_delta = c->allocate_size<HBINT16> (HBUINT16::static_size * segments.len);
      HBUINT16 *id_range_offset = c->allocate_size<HBUINT16> (HBUINT16::static_size * segments.len);
  
      if (id_range_offset == nullptr)
        return_trace (false);
  
      for (unsigned int i = 0; i < segments.len; i++)
      {
        end_count[i].set (segments[i].end_code);
        start_count[i].set (segments[i].start_code);
        if (segments[i].use_delta)
        {
          hb_codepoint_t cp = segments[i].start_code;
          hb_codepoint_t start_gid = 0;
          if (unlikely (!plan->new_gid_for_codepoint (cp, &start_gid) && cp != 0xFFFF))
            return_trace (false);
          id_delta[i].set (start_gid - segments[i].start_code);
        } else {
          id_delta[i].set (0);
          unsigned int num_codepoints = segments[i].end_code - segments[i].start_code + 1;
          HBUINT16 *glyph_id_array = c->allocate_size<HBUINT16> (HBUINT16::static_size * num_codepoints);
          if (glyph_id_array == nullptr)
            return_trace (false);
          // From the cmap spec:
          //
          // id_range_offset[i]/2
          // + (cp - segments[i].start_code)
          // + (id_range_offset + i)
          // =
          // glyph_id_array + (cp - segments[i].start_code)
          //
          // So, solve for id_range_offset[i]:
          //
          // id_range_offset[i]
          // =
          // 2 * (glyph_id_array - id_range_offset - i)
          id_range_offset[i].set (2 * (
              glyph_id_array - id_range_offset - i));
          for (unsigned int j = 0; j < num_codepoints; j++)
          {
            hb_codepoint_t cp = segments[i].start_code + j;
            hb_codepoint_t new_gid;
            if (unlikely (!plan->new_gid_for_codepoint (cp, &new_gid)))
              return_trace (false);
            glyph_id_array[j].set (new_gid);
          }
        }
      }
  
      return_trace (true);
    }
  
    static inline size_t get_sub_table_size (const hb_vector_t<segment_plan> &segments)
    {
      size_t segment_size = 0;
      for (unsigned int i = 0; i < segments.len; i++)
      {
        // Parallel array entries
        segment_size +=
              2  // end count
            + 2  // start count
            + 2  // delta
            + 2; // range offset
  
        if (!segments[i].use_delta)
          // Add bytes for the glyph index array entries for this segment.
          segment_size += (segments[i].end_code - segments[i].start_code + 1) * 2;
      }
  
      return min_size
          + 2 // Padding
          + segment_size;
    }
  
    static inline bool create_sub_table_plan (const hb_subset_plan_t *plan,
                                              hb_vector_t<segment_plan> *segments)
    {
      segment_plan *segment = nullptr;
      hb_codepoint_t last_gid = 0;
  
      hb_codepoint_t cp = HB_SET_VALUE_INVALID;
      while (plan->unicodes->next (&cp)) {
        hb_codepoint_t new_gid;
        if (unlikely (!plan->new_gid_for_codepoint (cp, &new_gid)))
        {
  	DEBUG_MSG(SUBSET, nullptr, "Unable to find new gid for %04x", cp);
  	return false;
        }
  
        if (cp > 0xFFFF) {
          // We are now outside of unicode BMP, stop adding to this cmap.
          break;
        }
  
        if (!segment
            || cp != segment->end_code + 1u)
        {
          segment = segments->push ();
          segment->start_code.set (cp);
          segment->end_code.set (cp);
          segment->use_delta = true;
        } else {
          segment->end_code.set (cp);
          if (last_gid + 1u != new_gid)
            // gid's are not consecutive in this segment so delta
            // cannot be used.
            segment->use_delta = false;
        }
  
        last_gid = new_gid;
      }
  
      // There must be a final entry with end_code == 0xFFFF. Check if we need to add one.
      if (segment == nullptr || segment->end_code != 0xFFFF) {
        segment = segments->push ();
        segment->start_code.set (0xFFFF);
        segment->end_code.set (0xFFFF);
        segment->use_delta = true;
      }
  
      return true;
    }
  
    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;
      }
  
      static inline void get_all_codepoints_func (const void *obj, hb_set_t *out)
      {
        const accelerator_t *thiz = (const accelerator_t *) obj;
        for (unsigned int i = 0; i < thiz->segCount; i++)
        {
  	if (thiz->startCount[i] != 0xFFFFu
  	    || thiz->endCount[i] != 0xFFFFu) // Skip the last segment (0xFFFF)
  	  hb_set_add_range (out, thiz->startCount[i], thiz->endCount[i]);
        }
      }
  
      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	language;	/* Ignore. */
    HBUINT16	segCountX2;	/* 2 x segCount. */
    HBUINT16	searchRange;	/* 2 * (2**floor(log2(segCount))) */
    HBUINT16	entrySelector;	/* log2(searchRange/2) */
    HBUINT16	rangeShift;	/* 2 x segCount - searchRange */
  
    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;
    template<typename U>
    friend struct CmapSubtableLongSegmented;
    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		length;		/* Byte length of this subtable. */
    UINT		language;	/* Ignore. */
    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 void get_all_codepoints (hb_set_t *out) const
    {
      for (unsigned int i = 0; i < this->groups.len; i++) {
        hb_set_add_range (out,
  			this->groups[i].startCharCode,
  			this->groups[i].endCharCode);
      }
    }
  
    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,
                           const hb_vector_t<CmapSubtableLongGroup> &group_data)
    {
      TRACE_SERIALIZE (this);
      if (unlikely (!c->extend_min (*this))) return_trace (false);
      Supplier<CmapSubtableLongGroup> supplier (group_data.arrayZ, group_data.len);
      if (unlikely (!groups.serialize (c, supplier, group_data.len))) return_trace (false);
      return true;
    }
  
    protected:
    HBUINT16	format;		/* Subtable format; set to 12. */
    HBUINT16	reserved;	/* Reserved; set to 0. */
    HBUINT32	length;		/* Byte length of this subtable. */
    HBUINT32	language;	/* Ignore. */
    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); }
  
  
    bool serialize (hb_serialize_context_t *c,
                    const hb_vector_t<CmapSubtableLongGroup> &groups)
    {
      if (unlikely (!c->extend_min (*this))) return false;
  
      this->format.set (12);
      this->reserved.set (0);
      this->length.set (get_sub_table_size (groups));
  
      return CmapSubtableLongSegmented<CmapSubtableFormat12>::serialize (c, groups);
    }
  
    static inline size_t get_sub_table_size (const hb_vector_t<CmapSubtableLongGroup> &groups)
    {
      return 16 + 12 * groups.len;
    }
  
    static inline bool create_sub_table_plan (const hb_subset_plan_t *plan,
                                              hb_vector_t<CmapSubtableLongGroup> *groups)
    {
      CmapSubtableLongGroup *group = nullptr;
  
      hb_codepoint_t cp = HB_SET_VALUE_INVALID;
      while (plan->unicodes->next (&cp)) {
        hb_codepoint_t new_gid;
        if (unlikely (!plan->new_gid_for_codepoint (cp, &new_gid)))
        {
  	DEBUG_MSG(SUBSET, nullptr, "Unable to find new gid for %04x", cp);
  	return false;
        }
  
        if (!group || !_is_gid_consecutive (group, cp, new_gid))
        {
          group = groups->push ();
          group->startCharCode.set (cp);
          group->endCharCode.set (cp);
          group->glyphID.set (new_gid);
        } else
        {
          group->endCharCode.set (cp);
        }
      }
  
      DEBUG_MSG(SUBSET, nullptr, "cmap");
      for (unsigned int i = 0; i < groups->len; i++) {
        CmapSubtableLongGroup& group = (*groups)[i];
        DEBUG_MSG(SUBSET, nullptr, "  %d: U+%04X-U+%04X, gid %d-%d", i, (uint32_t) group.startCharCode, (uint32_t) group.endCharCode, (uint32_t) group.glyphID, (uint32_t) group.glyphID + ((uint32_t) group.endCharCode - (uint32_t) group.startCharCode));
      }
  
      return true;
    }
  
   private:
    static inline bool _is_gid_consecutive (CmapSubtableLongGroup *group,
  					  hb_codepoint_t cp,
  					  hb_codepoint_t new_gid)
    {
      return (cp - 1 == group->endCharCode) &&
  	new_gid == group->glyphID + (cp - group->startCharCode);
    }
  
  };
  
  struct CmapSubtableFormat13 : CmapSubtableLongSegmented<CmapSubtableFormat13>
  {
    static inline hb_codepoint_t group_get_glyph (const CmapSubtableLongGroup &group,
  						hb_codepoint_t u HB_UNUSED)
    { return group.glyphID; }
  };
  
  typedef enum
  {
    GLYPH_VARIANT_NOT_FOUND = 0,
    GLYPH_VARIANT_FOUND = 1,
    GLYPH_VARIANT_USE_DEFAULT = 2
  } glyph_variant_t;
  
  struct UnicodeValueRange
  {
    inline int cmp (const hb_codepoint_t &codepoint) const
    {
      if (codepoint < startUnicodeValue) return -1;
      if (codepoint > startUnicodeValue + additionalCount) return +1;
      return 0;
    }
  
    inline bool sanitize (hb_sanitize_context_t *c) const
    {
      TRACE_SANITIZE (this);
      return_trace (c->check_struct (this));
    }
  
    HBUINT24	startUnicodeValue;	/* First value in this range. */
    HBUINT8		additionalCount;	/* Number of additional values in this
  					 * range. */
    public:
    DEFINE_SIZE_STATIC (4);
  };
  
  typedef SortedArrayOf<UnicodeValueRange, HBUINT32> DefaultUVS;
  
  struct UVSMapping
  {
    inline int cmp (const hb_codepoint_t &codepoint) const
    {
      return unicodeValue.cmp (codepoint);
    }
  
    inline bool sanitize (hb_sanitize_context_t *c) const
    {
      TRACE_SANITIZE (this);
      return_trace (c->check_struct (this));
    }
  
    HBUINT24	unicodeValue;	/* Base Unicode value of the UVS */
    GlyphID	glyphID;	/* Glyph ID of the UVS */
    public:
    DEFINE_SIZE_STATIC (5);
  };
  
  typedef SortedArrayOf<UVSMapping, HBUINT32> NonDefaultUVS;
  
  struct VariationSelectorRecord
  {
    inline glyph_variant_t get_glyph (hb_codepoint_t codepoint,
  				    hb_codepoint_t *glyph,
  				    const void *base) const
    {
      int i;
      const DefaultUVS &defaults = base+defaultUVS;
      i = defaults.bsearch (codepoint);
      if (i != -1)
        return GLYPH_VARIANT_USE_DEFAULT;
      const NonDefaultUVS &nonDefaults = base+nonDefaultUVS;
      i = nonDefaults.bsearch (codepoint);
      if (i != -1)
      {
        *glyph = nonDefaults[i].glyphID;
         return GLYPH_VARIANT_FOUND;
      }
      return GLYPH_VARIANT_NOT_FOUND;
    }
  
    inline int cmp (const hb_codepoint_t &variation_selector) const
    {
      return varSelector.cmp (variation_selector);
    }
  
    inline bool sanitize (hb_sanitize_context_t *c, const void *base) const
    {
      TRACE_SANITIZE (this);
      return_trace (c->check_struct (this) &&
  		  defaultUVS.sanitize (c, base) &&
  		  nonDefaultUVS.sanitize (c, base));
    }
  
    HBUINT24	varSelector;	/* Variation selector. */
    LOffsetTo<DefaultUVS>
  		defaultUVS;	/* Offset to Default UVS Table. May be 0. */
    LOffsetTo<NonDefaultUVS>
  		nonDefaultUVS;	/* Offset to Non-Default UVS Table. May be 0. */
    public:
    DEFINE_SIZE_STATIC (11);
  };
  
  struct CmapSubtableFormat14
  {
    inline glyph_variant_t get_glyph_variant (hb_codepoint_t codepoint,
  					    hb_codepoint_t variation_selector,
  					    hb_codepoint_t *glyph) const
    {
      return record[record.bsearch(variation_selector)].get_glyph (codepoint, glyph, this);
    }
  
    inline bool sanitize (hb_sanitize_context_t *c) const
    {
      TRACE_SANITIZE (this);
      return_trace (c->check_struct (this) &&
  		  record.sanitize (c, this));
    }
  
    protected:
    HBUINT16	format;		/* Format number is set to 14. */
    HBUINT32	length;		/* Byte length of this subtable. */
    SortedArrayOf<VariationSelectorRecord, HBUINT32>
  		record;		/* Variation selector records; sorted
  				 * in increasing order of `varSelector'. */
    public:
    DEFINE_SIZE_ARRAY (10, record);
  };
  
  struct CmapSubtable
  {
    /* Note: We intentionally do NOT implement subtable formats 2 and 8. */
  
    inline bool get_glyph (hb_codepoint_t codepoint,
  			 hb_codepoint_t *glyph) const
    {
      switch (u.format) {
      case  0: return u.format0 .get_glyph (codepoint, glyph);
      case  4: return u.format4 .get_glyph (codepoint, glyph);
      case  6: return u.format6 .get_glyph (codepoint, glyph);
      case 10: return u.format10.get_glyph (codepoint, glyph);
      case 12: return u.format12.get_glyph (codepoint, glyph);
      case 13: return u.format13.get_glyph (codepoint, glyph);
      case 14:
      default: return false;
      }
    }
  
    inline bool sanitize (hb_sanitize_context_t *c) const
    {
      TRACE_SANITIZE (this);
      if (!u.format.sanitize (c)) return_trace (false);
      switch (u.format) {
      case  0: return_trace (u.format0 .sanitize (c));
      case  4: return_trace (u.format4 .sanitize (c));
      case  6: return_trace (u.format6 .sanitize (c));
      case 10: return_trace (u.format10.sanitize (c));
      case 12: return_trace (u.format12.sanitize (c));
      case 13: return_trace (u.format13.sanitize (c));
      case 14: return_trace (u.format14.sanitize (c));
      default:return_trace (true);
      }
    }
  
    public:
    union {
    HBUINT16		format;		/* Format identifier */
    CmapSubtableFormat0	format0;
    CmapSubtableFormat4	format4;
    CmapSubtableFormat6	format6;
    CmapSubtableFormat10	format10;
    CmapSubtableFormat12	format12;
    CmapSubtableFormat13	format13;
    CmapSubtableFormat14	format14;
    } u;
    public:
    DEFINE_SIZE_UNION (2, format);
  };
  
  
  struct EncodingRecord
  {
    inline int cmp (const EncodingRecord &other) const
    {
      int ret;
      ret = platformID.cmp (other.platformID);
      if (ret) return ret;
      ret = encodingID.cmp (other.encodingID);
      if (ret) return ret;
      return 0;
    }
  
    inline bool sanitize (hb_sanitize_context_t *c, const void *base) const
    {
      TRACE_SANITIZE (this);
      return_trace (c->check_struct (this) &&
  		  subtable.sanitize (c, base));
    }
  
    HBUINT16	platformID;	/* Platform ID. */
    HBUINT16	encodingID;	/* Platform-specific encoding ID. */
    LOffsetTo<CmapSubtable>
  		subtable;	/* Byte offset from beginning of table to the subtable for this encoding. */
    public:
    DEFINE_SIZE_STATIC (8);
  };
  
  struct cmap
  {
    static const hb_tag_t tableTag	= HB_OT_TAG_cmap;
  
    struct subset_plan {
      subset_plan(void)
      {
        format4_segments.init();
        format12_groups.init();
      }
  
      ~subset_plan(void)
      {
        format4_segments.fini();
        format12_groups.fini();
      }
  
      inline size_t final_size() const
      {
        return 4 // header
            +  8 * 3 // 3 EncodingRecord
            +  CmapSubtableFormat4::get_sub_table_size (this->format4_segments)
            +  CmapSubtableFormat12::get_sub_table_size (this->format12_groups);
      }
  
      // Format 4
      hb_vector_t<CmapSubtableFormat4::segment_plan> format4_segments;
      // Format 12
      hb_vector_t<CmapSubtableLongGroup> format12_groups;
    };
  
    inline bool sanitize (hb_sanitize_context_t *c) const
    {
      TRACE_SANITIZE (this);
      return_trace (c->check_struct (this) &&
  		  likely (version == 0) &&
  		  encodingRecord.sanitize (c, this));
    }
  
    inline bool _create_plan (const hb_subset_plan_t *plan,
                              subset_plan *cmap_plan) const
    {
      if (unlikely( !CmapSubtableFormat4::create_sub_table_plan (plan, &cmap_plan->format4_segments)))
        return false;
  
      return CmapSubtableFormat12::create_sub_table_plan (plan, &cmap_plan->format12_groups);
    }
  
    inline bool _subset (const hb_subset_plan_t *plan,
                         const subset_plan &cmap_subset_plan,
  		       size_t dest_sz,
  		       void *dest) const
    {
      hb_serialize_context_t c (dest, dest_sz);
  
      OT::cmap *cmap = c.start_serialize<OT::cmap> ();
      if (unlikely (!c.extend_min (*cmap)))
      {
        return false;
      }
  
      cmap->version.set (0);
  
      if (unlikely (!cmap->encodingRecord.serialize (&c, /* numTables */ 3)))
        return false;
  
      // TODO(grieger): Convert the below to a for loop
  
      // Format 4, Plat 0 Encoding Record
      EncodingRecord &format4_plat0_rec = cmap->encodingRecord[0];
      format4_plat0_rec.platformID.set (0); // Unicode
      format4_plat0_rec.encodingID.set (3);
  
      // Format 4, Plat 3 Encoding Record
      EncodingRecord &format4_plat3_rec = cmap->encodingRecord[1];
      format4_plat3_rec.platformID.set (3); // Windows
      format4_plat3_rec.encodingID.set (1); // Unicode BMP
  
      // Format 12 Encoding Record
      EncodingRecord &format12_rec = cmap->encodingRecord[2];
      format12_rec.platformID.set (3); // Windows
      format12_rec.encodingID.set (10); // Unicode UCS-4
  
      // Write out format 4 sub table
      {
        CmapSubtable &subtable = format4_plat0_rec.subtable.serialize (&c, cmap);
        format4_plat3_rec.subtable.set (format4_plat0_rec.subtable);
        subtable.u.format.set (4);
  
        CmapSubtableFormat4 &format4 = subtable.u.format4;
        if (unlikely (!format4.serialize (&c, plan, cmap_subset_plan.format4_segments)))
          return false;
      }
  
      // Write out format 12 sub table.
      {
        CmapSubtable &subtable = format12_rec.subtable.serialize (&c, cmap);
        subtable.u.format.set (12);
  
        CmapSubtableFormat12 &format12 = subtable.u.format12;
        if (unlikely (!format12.serialize (&c, cmap_subset_plan.format12_groups)))
          return false;
      }
  
      c.end_serialize ();
  
      return true;
    }
  
    inline bool subset (hb_subset_plan_t *plan) const
    {
      subset_plan cmap_subset_plan;
  
      if (unlikely (!_create_plan (plan, &cmap_subset_plan)))
      {
        DEBUG_MSG(SUBSET, nullptr, "Failed to generate a cmap subsetting plan.");
        return false;
      }
  
      // We now know how big our blob needs to be
      size_t dest_sz = cmap_subset_plan.final_size();
      void *dest = malloc (dest_sz);
      if (unlikely (!dest)) {
        DEBUG_MSG(SUBSET, nullptr, "Unable to alloc %lu for cmap subset output", (unsigned long) dest_sz);
        return false;
      }
  
      if (unlikely (!_subset (plan, cmap_subset_plan, dest_sz, dest)))
      {
        DEBUG_MSG(SUBSET, nullptr, "Failed to perform subsetting of cmap.");
        free (dest);
        return false;
      }
  
      // all done, write the blob into dest
      hb_blob_t *cmap_prime = hb_blob_create ((const char *)dest,
                                              dest_sz,
                                              HB_MEMORY_MODE_READONLY,
                                              dest,
                                              free);
      bool result =  plan->add_table (HB_OT_TAG_cmap, cmap_prime);
      hb_blob_destroy (cmap_prime);
      return result;
    }
  
    struct accelerator_t
    {
      inline void init (hb_face_t *face)
      {
        this->blob = OT::Sanitizer<OT::cmap>().sanitize (face->reference_table (HB_OT_TAG_cmap));
        const OT::cmap *cmap = this->blob->as<OT::cmap> ();
        const OT::CmapSubtable *subtable = nullptr;
        const OT::CmapSubtableFormat14 *subtable_uvs = nullptr;
  
        bool symbol = false;
        /* 32-bit subtables. */
        if (!subtable) subtable = cmap->find_subtable (3, 10);
        if (!subtable) subtable = cmap->find_subtable (0, 6);
        if (!subtable) subtable = cmap->find_subtable (0, 4);
        /* 16-bit subtables. */
        if (!subtable) subtable = cmap->find_subtable (3, 1);
        if (!subtable) subtable = cmap->find_subtable (0, 3);
        if (!subtable) subtable = cmap->find_subtable (0, 2);
        if (!subtable) subtable = cmap->find_subtable (0, 1);
        if (!subtable) subtable = cmap->find_subtable (0, 0);
        if (!subtable)
        {
  	subtable = cmap->find_subtable (3, 0);
  	if (subtable) symbol = true;
        }
        /* Meh. */
        if (!subtable) subtable = &Null(OT::CmapSubtable);
  
        /* UVS subtable. */
        if (!subtable_uvs)
        {
  	const OT::CmapSubtable *st = cmap->find_subtable (0, 5);
  	if (st && st->u.format == 14)
  	  subtable_uvs = &st->u.format14;
        }
        /* Meh. */
        if (!subtable_uvs) subtable_uvs = &Null(OT::CmapSubtableFormat14);
  
        this->uvs_table = subtable_uvs;
  
        this->get_glyph_data = subtable;
        if (unlikely (symbol))
        {
  	this->get_glyph_func = get_glyph_from_symbol<OT::CmapSubtable>;
  	this->get_all_codepoints_func = null_get_all_codepoints_func;
        } else {
  	switch (subtable->u.format) {
  	/* Accelerate format 4 and format 12. */
  	default:
  	  this->get_glyph_func = get_glyph_from<OT::CmapSubtable>;
  	  this->get_all_codepoints_func = null_get_all_codepoints_func;
  	  break;
  	case 12:
  	  this->get_glyph_func = get_glyph_from<OT::CmapSubtableFormat12>;
  	  this->get_all_codepoints_func = get_all_codepoints_from<OT::CmapSubtableFormat12>;
  	  break;
  	case  4:
  	  {
  	    this->format4_accel.init (&subtable->u.format4);
  	    this->get_glyph_data = &this->format4_accel;
  	    this->get_glyph_func = this->format4_accel.get_glyph_func;
  	    this->get_all_codepoints_func = this->format4_accel.get_all_codepoints_func;
  	  }
  	  break;
  	}
        }
      }
  
      inline void fini (void)
      {
        hb_blob_destroy (this->blob);
      }
  
      inline bool get_nominal_glyph (hb_codepoint_t  unicode,
  				   hb_codepoint_t *glyph) const
      {
        return this->get_glyph_func (this->get_glyph_data, unicode, glyph);
      }
  
      inline bool get_variation_glyph (hb_codepoint_t  unicode,
  				     hb_codepoint_t  variation_selector,
  				     hb_codepoint_t *glyph) const
      {
        switch (this->uvs_table->get_glyph_variant (unicode,
  						  variation_selector,
  						  glyph))
        {
  	case OT::GLYPH_VARIANT_NOT_FOUND:		return false;
  	case OT::GLYPH_VARIANT_FOUND:		return true;
  	case OT::GLYPH_VARIANT_USE_DEFAULT:	break;
        }
  
        return get_nominal_glyph (unicode, glyph);
      }
  
      inline void get_all_codepoints (hb_set_t *out) const
      {
        this->get_all_codepoints_func (get_glyph_data, out);
      }
  
      protected:
      typedef bool (*hb_cmap_get_glyph_func_t) (const void *obj,
  					      hb_codepoint_t codepoint,
  					      hb_codepoint_t *glyph);
      typedef void (*hb_cmap_get_all_codepoints_func_t) (const void *obj,
  						       hb_set_t *out);
  
      static inline void null_get_all_codepoints_func (const void *obj, hb_set_t *out)
      {
        // NOOP
      }
  
      template <typename Type>
      static inline bool get_glyph_from (const void *obj,
  				       hb_codepoint_t codepoint,
  				       hb_codepoint_t *glyph)
      {
        const Type *typed_obj = (const Type *) obj;
        return typed_obj->get_glyph (codepoint, glyph);
      }
  
      template <typename Type>
      static inline void get_all_codepoints_from (const void *obj,
  						hb_set_t *out)
      {
        const Type *typed_obj = (const Type *) obj;
        typed_obj->get_all_codepoints (out);
      }
  
      template <typename Type>
      static inline bool get_glyph_from_symbol (const void *obj,
  					      hb_codepoint_t codepoint,
  					      hb_codepoint_t *glyph)
      {
        const Type *typed_obj = (const Type *) obj;
        if (likely (typed_obj->get_glyph (codepoint, glyph)))
  	return true;
  
        if (codepoint <= 0x00FFu)
        {
  	/* For symbol-encoded OpenType fonts, we duplicate the
  	 * U+F000..F0FF range at U+0000..U+00FF.  That's what
  	 * Windows seems to do, and that's hinted about at:
  	 * https://docs.microsoft.com/en-us/typography/opentype/spec/recom
  	 * under "Non-Standard (Symbol) Fonts". */
  	return typed_obj->get_glyph (0xF000u + codepoint, glyph);
        }
  
        return false;
      }
  
      private:
      hb_cmap_get_glyph_func_t get_glyph_func;
      const void *get_glyph_data;
      hb_cmap_get_all_codepoints_func_t get_all_codepoints_func;
  
      OT::CmapSubtableFormat4::accelerator_t format4_accel;
  
      const OT::CmapSubtableFormat14 *uvs_table;
      hb_blob_t *blob;
    };
  
    protected:
  
    inline const CmapSubtable *find_subtable (unsigned int platform_id,
  					    unsigned int encoding_id) const
    {
      EncodingRecord key;
      key.platformID.set (platform_id);
      key.encodingID.set (encoding_id);
  
      /* Note: We can use bsearch, but since it has no performance
       * implications, we use lsearch and as such accept fonts with
       * unsorted subtable list. */
      int result = encodingRecord./*bsearch*/lsearch (key);
      if (result == -1 || !encodingRecord[result].subtable)
        return nullptr;
  
      return &(this+encodingRecord[result].subtable);
    }
  
    protected:
    HBUINT16		version;	/* Table version number (0). */
    SortedArrayOf<EncodingRecord>
  			encodingRecord;	/* Encoding tables. */
    public:
    DEFINE_SIZE_ARRAY (4, encodingRecord);
  };
  
  
  } /* namespace OT */
  
  
  #endif /* HB_OT_CMAP_TABLE_HH */
  

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