--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mupdf-source/thirdparty/harfbuzz/src/hb-ot-cmap-table.hh	Mon Sep 15 11:43:07 2025 +0200
@@ -0,0 +1,2072 @@
+/*
+ * 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-ot-os2-table.hh"
+#include "hb-ot-shaper-arabic-pua.hh"
+#include "hb-open-type.hh"
+#include "hb-set.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
+{
+  bool get_glyph (hb_codepoint_t codepoint, hb_codepoint_t *glyph) const
+  {
+    hb_codepoint_t gid = codepoint < 256 ? glyphIdArray[codepoint] : 0;
+    if (unlikely (!gid))
+      return false;
+    *glyph = gid;
+    return true;
+  }
+
+  unsigned get_language () const
+  {
+    return language;
+  }
+
+  void collect_unicodes (hb_set_t *out) const
+  {
+    for (unsigned int i = 0; i < 256; i++)
+      if (glyphIdArray[i])
+	out->add (i);
+  }
+
+  void collect_mapping (hb_set_t *unicodes, /* OUT */
+			hb_map_t *mapping /* OUT */) const
+  {
+    for (unsigned i = 0; i < 256; i++)
+      if (glyphIdArray[i])
+      {
+	hb_codepoint_t glyph = glyphIdArray[i];
+	unicodes->add (i);
+	mapping->set (i, glyph);
+      }
+  }
+
+  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
+{
+
+
+  template<typename Iterator,
+      typename Writer,
+	   hb_requires (hb_is_iterator (Iterator))>
+  void to_ranges (Iterator it, Writer& range_writer)
+  {
+    hb_codepoint_t start_cp = 0, prev_run_start_cp = 0, run_start_cp = 0, end_cp = 0, last_gid = 0;
+    int run_length = 0 , delta = 0, prev_delta = 0;
+
+    enum {
+      FIRST_SUB_RANGE,
+      FOLLOWING_SUB_RANGE,
+    } mode;
+
+    while (it) {
+      // Start a new range
+      {
+        const auto& pair = *it;
+        start_cp = pair.first;
+        prev_run_start_cp = start_cp;
+        run_start_cp = start_cp;
+        end_cp = start_cp;
+        last_gid = pair.second;
+        run_length = 1;
+        prev_delta = 0;
+      }
+
+      delta = last_gid - start_cp;
+      mode = FIRST_SUB_RANGE;
+      it++;
+
+      while (it) {
+        // Process range
+        const auto& pair = *it;
+        hb_codepoint_t next_cp = pair.first;
+        hb_codepoint_t next_gid = pair.second;
+        if (next_cp != end_cp + 1) {
+          // Current range is over, stop processing.
+          break;
+        }
+
+        if (next_gid == last_gid + 1) {
+          // The current run continues.
+          end_cp = next_cp;
+          run_length++;
+          last_gid = next_gid;
+          it++;
+          continue;
+        }
+
+        // A new run is starting, decide if we want to commit the current run.
+        int split_cost = (mode == FIRST_SUB_RANGE) ? 8 : 16;
+        int run_cost = run_length * 2;
+        if (run_cost >= split_cost) {
+          commit_current_range(start_cp,
+                               prev_run_start_cp,
+                               run_start_cp,
+                               end_cp,
+                               delta,
+                               prev_delta,
+                               split_cost,
+                               range_writer);
+          start_cp = next_cp;
+        }
+
+        // Start the new run
+        mode = FOLLOWING_SUB_RANGE;
+        prev_run_start_cp = run_start_cp;
+        run_start_cp = next_cp;
+        end_cp = next_cp;
+        prev_delta = delta;
+        delta = next_gid - run_start_cp;
+        run_length = 1;
+        last_gid = next_gid;
+        it++;
+      }
+
+      // Finalize range
+      commit_current_range (start_cp,
+                            prev_run_start_cp,
+                            run_start_cp,
+                            end_cp,
+                            delta,
+                            prev_delta,
+                            8,
+                            range_writer);
+    }
+
+    if (likely (end_cp != 0xFFFF)) {
+      range_writer (0xFFFF, 0xFFFF, 1);
+    }
+  }
+
+  /*
+   * Writes the current range as either one or two ranges depending on what is most efficient.
+   */
+  template<typename Writer>
+  void commit_current_range (hb_codepoint_t start,
+                             hb_codepoint_t prev_run_start,
+                             hb_codepoint_t run_start,
+                             hb_codepoint_t end,
+                             int run_delta,
+                             int previous_run_delta,
+                             int split_cost,
+                             Writer& range_writer) {
+    bool should_split = false;
+    if (start < run_start && run_start < end) {
+      int run_cost = (end - run_start + 1) * 2;
+      if (run_cost >= split_cost) {
+        should_split = true;
+      }
+    }
+
+    // TODO(grieger): handle case where delta is legitimately 0, mark range offset array instead?
+    if (should_split) {
+      if (start == prev_run_start)
+        range_writer (start, run_start - 1, previous_run_delta);
+      else
+        range_writer (start, run_start - 1, 0);
+      range_writer (run_start, end, run_delta);
+      return;
+    }
+
+
+    if (start == run_start) {
+      // Range is only a run
+      range_writer (start, end, run_delta);
+      return;
+    }
+
+    // Write only a single non-run range.
+    range_writer (start, end, 0);
+  }
+
+  template<typename Iterator,
+	   hb_requires (hb_is_iterator (Iterator))>
+  unsigned serialize_find_segcount (Iterator it) {
+    struct Counter {
+      unsigned segcount = 0;
+
+      void operator() (hb_codepoint_t start,
+                       hb_codepoint_t end,
+                       int delta) {
+        segcount++;
+      }
+    } counter;
+
+    to_ranges (+it, counter);
+    return counter.segcount;
+  }
+
+
+  template<typename Iterator,
+	   hb_requires (hb_is_iterator (Iterator))>
+  bool serialize_start_end_delta_arrays (hb_serialize_context_t *c,
+                                         Iterator it,
+                                         int segcount)
+  {
+    struct Writer {
+      hb_serialize_context_t *serializer_;
+      HBUINT16* end_code_;
+      HBUINT16* start_code_;
+      HBINT16* id_delta_;
+      int index_;
+
+      Writer(hb_serialize_context_t *serializer)
+          : serializer_(serializer),
+            end_code_(nullptr),
+            start_code_(nullptr),
+            id_delta_(nullptr),
+            index_ (0) {}
+      void operator() (hb_codepoint_t start,
+                       hb_codepoint_t end,
+                       int delta) {
+        start_code_[index_] = start;
+        end_code_[index_] = end;
+        id_delta_[index_] = delta;
+        index_++;
+      }
+    } writer(c);
+
+    writer.end_code_ = c->allocate_size<HBUINT16> (HBUINT16::static_size * segcount);
+    c->allocate_size<HBUINT16> (2); // padding
+    writer.start_code_ = c->allocate_size<HBUINT16> (HBUINT16::static_size * segcount);
+    writer.id_delta_ = c->allocate_size<HBINT16> (HBINT16::static_size * segcount);
+
+    if (unlikely (!writer.end_code_ || !writer.start_code_ || !writer.id_delta_)) return false;
+
+    to_ranges (+it, writer);
+    return true;
+  }
+
+  template<typename Iterator,
+          hb_requires (hb_is_iterator (Iterator))>
+  HBUINT16* serialize_rangeoffset_glyid (hb_serialize_context_t *c,
+                                         Iterator it,
+					 HBUINT16 *endCode,
+					 HBUINT16 *startCode,
+					 HBINT16 *idDelta,
+					 unsigned segcount)
+  {
+    hb_map_t cp_to_gid { it };
+
+    HBUINT16 *idRangeOffset = c->allocate_size<HBUINT16> (HBUINT16::static_size * segcount);
+    if (unlikely (!c->check_success (idRangeOffset))) return nullptr;
+    if (unlikely ((char *)idRangeOffset - (char *)idDelta != (int) segcount * (int) HBINT16::static_size)) return nullptr;
+
+    for (unsigned i : + hb_range (segcount)
+		      | hb_filter ([&] (const unsigned _) { return idDelta[_] == 0; }))
+    {
+      idRangeOffset[i] = 2 * (c->start_embed<HBUINT16> () - idRangeOffset - i);
+      for (hb_codepoint_t cp = startCode[i]; cp <= endCode[i]; cp++)
+      {
+        HBUINT16 gid;
+        gid = cp_to_gid[cp];
+        c->copy<HBUINT16> (gid);
+      }
+    }
+
+    return idRangeOffset;
+  }
+
+  template<typename Iterator,
+	   hb_requires (hb_is_iterator (Iterator))>
+  void serialize (hb_serialize_context_t *c,
+		  Iterator it)
+  {
+    auto format4_iter =
+    + it
+    | hb_filter ([&] (const hb_pair_t<hb_codepoint_t, hb_codepoint_t> _)
+		 { return _.first <= 0xFFFF; })
+    ;
+
+    if (!format4_iter) return;
+
+    unsigned table_initpos = c->length ();
+    if (unlikely (!c->extend_min (this))) return;
+    this->format = 4;
+
+    hb_vector_t<hb_pair_t<hb_codepoint_t, hb_codepoint_t>> cp_to_gid {
+      format4_iter
+    };
+
+    //serialize endCode[], startCode[], idDelta[]
+    HBUINT16* endCode = c->start_embed<HBUINT16> ();
+    unsigned segcount = serialize_find_segcount (cp_to_gid.iter());
+    if (unlikely (!serialize_start_end_delta_arrays (c, cp_to_gid.iter(), segcount)))
+      return;
+
+    HBUINT16 *startCode = endCode + segcount + 1;
+    HBINT16 *idDelta = ((HBINT16*)startCode) + segcount;
+
+    HBUINT16 *idRangeOffset = serialize_rangeoffset_glyid (c,
+                                                           cp_to_gid.iter (),
+                                                           endCode,
+                                                           startCode,
+                                                           idDelta,
+                                                           segcount);
+    if (unlikely (!c->check_success (idRangeOffset))) return;
+
+    this->length = c->length () - table_initpos;
+    if ((long long) this->length != (long long) c->length () - table_initpos)
+    {
+      // Length overflowed. Discard the current object before setting the error condition, otherwise
+      // discard is a noop which prevents the higher level code from reverting the serializer to the
+      // pre-error state in cmap4 overflow handling code.
+      c->pop_discard ();
+      c->err (HB_SERIALIZE_ERROR_INT_OVERFLOW);
+      return;
+    }
+
+    this->segCountX2 = segcount * 2;
+    this->entrySelector = hb_max (1u, hb_bit_storage (segcount)) - 1;
+    this->searchRange = 2 * (1u << this->entrySelector);
+    this->rangeShift = segcount * 2 > this->searchRange
+		       ? 2 * segcount - this->searchRange
+		       : 0;
+  }
+
+  unsigned get_language () const
+  {
+    return language;
+  }
+
+  struct accelerator_t
+  {
+    accelerator_t () {}
+    accelerator_t (const CmapSubtableFormat4 *subtable) { init (subtable); }
+
+    void init (const CmapSubtableFormat4 *subtable)
+    {
+      segCount = subtable->segCountX2 / 2;
+      endCount = subtable->values.arrayZ;
+      startCount = endCount + segCount + 1;
+      idDelta = startCount + segCount;
+      idRangeOffset = idDelta + segCount;
+      glyphIdArray = idRangeOffset + segCount;
+      glyphIdArrayLength = (subtable->length - 16 - 8 * segCount) / 2;
+    }
+
+    bool get_glyph (hb_codepoint_t codepoint, hb_codepoint_t *glyph) const
+    {
+      struct CustomRange
+      {
+	int cmp (hb_codepoint_t k,
+		 unsigned distance) const
+	{
+	  if (k > last) return +1;
+	  if (k < (&last)[distance]) return -1;
+	  return 0;
+	}
+	HBUINT16 last;
+      };
+
+      const HBUINT16 *found = hb_bsearch (codepoint,
+					  this->endCount,
+					  this->segCount,
+					  2,
+					  _hb_cmp_method<hb_codepoint_t, CustomRange, unsigned>,
+					  this->segCount + 1);
+      if (unlikely (!found))
+	return false;
+      unsigned int i = found - endCount;
+
+      hb_codepoint_t gid;
+      unsigned int rangeOffset = this->idRangeOffset[i];
+      if (rangeOffset == 0)
+	gid = codepoint + this->idDelta[i];
+      else
+      {
+	/* Somebody has been smoking... */
+	unsigned int index = rangeOffset / 2 + (codepoint - this->startCount[i]) + i - this->segCount;
+	if (unlikely (index >= this->glyphIdArrayLength))
+	  return false;
+	gid = this->glyphIdArray[index];
+	if (unlikely (!gid))
+	  return false;
+	gid += this->idDelta[i];
+      }
+      gid &= 0xFFFFu;
+      if (unlikely (!gid))
+	return false;
+      *glyph = gid;
+      return true;
+    }
+
+    HB_INTERNAL static bool get_glyph_func (const void *obj, hb_codepoint_t codepoint, hb_codepoint_t *glyph)
+    { return ((const accelerator_t *) obj)->get_glyph (codepoint, glyph); }
+
+    void collect_unicodes (hb_set_t *out) const
+    {
+      unsigned int count = this->segCount;
+      if (count && this->startCount[count - 1] == 0xFFFFu)
+	count--; /* Skip sentinel segment. */
+      for (unsigned int i = 0; i < count; i++)
+      {
+	hb_codepoint_t start = this->startCount[i];
+	hb_codepoint_t end = this->endCount[i];
+	unsigned int rangeOffset = this->idRangeOffset[i];
+        out->add_range(start, end);
+	if (rangeOffset == 0)
+	{
+	  for (hb_codepoint_t codepoint = start; codepoint <= end; codepoint++)
+	  {
+	    hb_codepoint_t gid = (codepoint + this->idDelta[i]) & 0xFFFFu;
+	    if (unlikely (!gid))
+              out->del(codepoint);
+	  }
+	}
+	else
+	{
+	  for (hb_codepoint_t codepoint = start; codepoint <= end; codepoint++)
+	  {
+	    unsigned int index = rangeOffset / 2 + (codepoint - this->startCount[i]) + i - this->segCount;
+	    if (unlikely (index >= this->glyphIdArrayLength))
+            {
+              out->del_range (codepoint, end);
+	      break;
+            }
+	    hb_codepoint_t gid = this->glyphIdArray[index];
+	    if (unlikely (!gid))
+              out->del(codepoint);
+	  }
+	}
+      }
+    }
+
+    void collect_mapping (hb_set_t *unicodes, /* OUT */
+			  hb_map_t *mapping /* OUT */) const
+    {
+      // TODO(grieger): optimize similar to collect_unicodes
+      // (ie. use add_range())
+      unsigned count = this->segCount;
+      if (count && this->startCount[count - 1] == 0xFFFFu)
+	count--; /* Skip sentinel segment. */
+      for (unsigned i = 0; i < count; i++)
+      {
+	hb_codepoint_t start = this->startCount[i];
+	hb_codepoint_t end = this->endCount[i];
+	unsigned rangeOffset = this->idRangeOffset[i];
+	if (rangeOffset == 0)
+	{
+	  for (hb_codepoint_t codepoint = start; codepoint <= end; codepoint++)
+	  {
+	    hb_codepoint_t gid = (codepoint + this->idDelta[i]) & 0xFFFFu;
+	    if (unlikely (!gid))
+	      continue;
+	    unicodes->add (codepoint);
+	    mapping->set (codepoint, gid);
+	  }
+	}
+	else
+	{
+	  for (hb_codepoint_t codepoint = start; codepoint <= end; codepoint++)
+	  {
+	    unsigned index = rangeOffset / 2 + (codepoint - this->startCount[i]) + i - this->segCount;
+	    if (unlikely (index >= this->glyphIdArrayLength))
+	      break;
+	    hb_codepoint_t gid = this->glyphIdArray[index];
+	    if (unlikely (!gid))
+	      continue;
+	    unicodes->add (codepoint);
+	    mapping->set (codepoint, gid);
+	  }
+	}
+      }
+    }
+
+    const HBUINT16 *endCount;
+    const HBUINT16 *startCount;
+    const HBUINT16 *idDelta;
+    const HBUINT16 *idRangeOffset;
+    const HBUINT16 *glyphIdArray;
+    unsigned int segCount;
+    unsigned int glyphIdArrayLength;
+  };
+
+  bool get_glyph (hb_codepoint_t codepoint, hb_codepoint_t *glyph) const
+  {
+    accelerator_t accel (this);
+    return accel.get_glyph_func (&accel, codepoint, glyph);
+  }
+  void collect_unicodes (hb_set_t *out) const
+  {
+    accelerator_t accel (this);
+    accel.collect_unicodes (out);
+  }
+
+  void collect_mapping (hb_set_t *unicodes, /* OUT */
+			hb_map_t *mapping /* OUT */) const
+  {
+    accelerator_t accel (this);
+    accel.collect_mapping (unicodes, mapping);
+  }
+
+  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) hb_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 */
+
+  UnsizedArrayOf<HBUINT16>
+		values;
+#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 */
+  UnsizedArrayOf<HBUINT16>
+		glyphIdArray;	/* 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;
+  }
+
+  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);
+};
+DECLARE_NULL_NAMESPACE_BYTES (OT, CmapSubtableLongGroup);
+
+template <typename UINT>
+struct CmapSubtableTrimmed
+{
+  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 (unlikely (!gid))
+      return false;
+    *glyph = gid;
+    return true;
+  }
+
+  unsigned get_language () const
+  {
+    return language;
+  }
+
+  void collect_unicodes (hb_set_t *out) const
+  {
+    hb_codepoint_t start = startCharCode;
+    unsigned int count = glyphIdArray.len;
+    for (unsigned int i = 0; i < count; i++)
+      if (glyphIdArray[i])
+	out->add (start + i);
+  }
+
+  void collect_mapping (hb_set_t *unicodes, /* OUT */
+			hb_map_t *mapping /* OUT */) const
+  {
+    hb_codepoint_t start_cp = startCharCode;
+    unsigned count = glyphIdArray.len;
+    for (unsigned i = 0; i < count; i++)
+      if (glyphIdArray[i])
+      {
+	hb_codepoint_t unicode = start_cp + i;
+	hb_codepoint_t glyphid = glyphIdArray[i];
+	unicodes->add (unicode);
+	mapping->set (unicode, glyphid);
+      }
+  }
+
+  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<HBGlyphID16, 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;
+
+  bool get_glyph (hb_codepoint_t codepoint, hb_codepoint_t *glyph) const
+  {
+    hb_codepoint_t gid = T::group_get_glyph (groups.bsearch (codepoint), codepoint);
+    if (unlikely (!gid))
+      return false;
+    *glyph = gid;
+    return true;
+  }
+
+  unsigned get_language () const
+  {
+    return language;
+  }
+
+  void collect_unicodes (hb_set_t *out, unsigned int num_glyphs) const
+  {
+    for (unsigned int i = 0; i < this->groups.len; i++)
+    {
+      hb_codepoint_t start = this->groups[i].startCharCode;
+      hb_codepoint_t end = hb_min ((hb_codepoint_t) this->groups[i].endCharCode,
+				   (hb_codepoint_t) HB_UNICODE_MAX);
+      hb_codepoint_t gid = this->groups[i].glyphID;
+      if (!gid)
+      {
+	/* Intention is: if (hb_is_same (T, CmapSubtableFormat13)) continue; */
+	if (! T::group_get_glyph (this->groups[i], end)) continue;
+	start++;
+	gid++;
+      }
+      if (unlikely ((unsigned int) gid >= num_glyphs)) continue;
+      if (unlikely ((unsigned int) (gid + end - start) >= num_glyphs))
+	end = start + (hb_codepoint_t) num_glyphs - gid;
+
+      out->add_range (start, hb_min (end, 0x10FFFFu));
+    }
+  }
+
+  void collect_mapping (hb_set_t *unicodes, /* OUT */
+			hb_map_t *mapping, /* OUT */
+			unsigned num_glyphs) const
+  {
+    hb_codepoint_t last_end = 0;
+    for (unsigned i = 0; i < this->groups.len; i++)
+    {
+      hb_codepoint_t start = this->groups[i].startCharCode;
+      hb_codepoint_t end = hb_min ((hb_codepoint_t) this->groups[i].endCharCode,
+				   (hb_codepoint_t) HB_UNICODE_MAX);
+      if (unlikely (start > end || start < last_end)) {
+        // Range is not in order and is invalid, skip it.
+        continue;
+      }
+      last_end = end;
+
+
+      hb_codepoint_t gid = this->groups[i].glyphID;
+      if (!gid)
+      {
+	/* Intention is: if (hb_is_same (T, CmapSubtableFormat13)) continue; */
+	if (! T::group_get_glyph (this->groups[i], end)) continue;
+	start++;
+	gid++;
+      }
+      if (unlikely ((unsigned int) gid >= num_glyphs)) continue;
+      if (unlikely ((unsigned int) (gid + end - start) >= num_glyphs))
+	end = start + (hb_codepoint_t) num_glyphs - gid;
+
+      for (unsigned cp = start; cp <= end; cp++)
+      {
+	unicodes->add (cp);
+	mapping->set (cp, gid);
+	gid++;
+      }
+    }
+  }
+
+  bool sanitize (hb_sanitize_context_t *c) const
+  {
+    TRACE_SANITIZE (this);
+    return_trace (c->check_struct (this) && groups.sanitize (c));
+  }
+
+  protected:
+  HBUINT16	format;		/* Subtable format; set to 12. */
+  HBUINT16	reserved;	/* Reserved; set to 0. */
+  HBUINT32	length;		/* Byte length of this subtable. */
+  HBUINT32	language;	/* Ignore. */
+  SortedArray32Of<CmapSubtableLongGroup>
+		groups;		/* Groupings. */
+  public:
+  DEFINE_SIZE_ARRAY (16, groups);
+};
+
+struct CmapSubtableFormat12 : CmapSubtableLongSegmented<CmapSubtableFormat12>
+{
+  static hb_codepoint_t group_get_glyph (const CmapSubtableLongGroup &group,
+					 hb_codepoint_t u)
+  { return likely (group.startCharCode <= group.endCharCode) ?
+	   group.glyphID + (u - group.startCharCode) : 0; }
+
+
+  template<typename Iterator,
+	   hb_requires (hb_is_iterator (Iterator))>
+  void serialize (hb_serialize_context_t *c,
+		  Iterator it)
+  {
+    if (!it) return;
+    unsigned table_initpos = c->length ();
+    if (unlikely (!c->extend_min (this))) return;
+
+    hb_codepoint_t startCharCode = (hb_codepoint_t) -1, endCharCode = (hb_codepoint_t) -1;
+    hb_codepoint_t glyphID = 0;
+
+    for (const auto& _ : +it)
+    {
+      if (startCharCode == (hb_codepoint_t) -1)
+      {
+	startCharCode = _.first;
+	endCharCode = _.first;
+	glyphID = _.second;
+      }
+      else if (!_is_gid_consecutive (endCharCode, startCharCode, glyphID, _.first, _.second))
+      {
+	CmapSubtableLongGroup  grouprecord;
+	grouprecord.startCharCode = startCharCode;
+	grouprecord.endCharCode = endCharCode;
+	grouprecord.glyphID = glyphID;
+	c->copy<CmapSubtableLongGroup> (grouprecord);
+
+	startCharCode = _.first;
+	endCharCode = _.first;
+	glyphID = _.second;
+      }
+      else
+	endCharCode = _.first;
+    }
+
+    CmapSubtableLongGroup record;
+    record.startCharCode = startCharCode;
+    record.endCharCode = endCharCode;
+    record.glyphID = glyphID;
+    c->copy<CmapSubtableLongGroup> (record);
+
+    this->format = 12;
+    this->reserved = 0;
+    this->length = c->length () - table_initpos;
+    this->groups.len = (this->length - min_size) / CmapSubtableLongGroup::static_size;
+  }
+
+  static size_t get_sub_table_size (const hb_sorted_vector_t<CmapSubtableLongGroup> &groups_data)
+  { return 16 + 12 * groups_data.length; }
+
+  private:
+  static bool _is_gid_consecutive (hb_codepoint_t endCharCode,
+				   hb_codepoint_t startCharCode,
+				   hb_codepoint_t glyphID,
+				   hb_codepoint_t cp,
+				   hb_codepoint_t new_gid)
+  {
+    return (cp - 1 == endCharCode) &&
+	new_gid == glyphID + (cp - startCharCode);
+  }
+
+};
+
+struct CmapSubtableFormat13 : CmapSubtableLongSegmented<CmapSubtableFormat13>
+{
+  static 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
+{
+  int cmp (const hb_codepoint_t &codepoint) const
+  {
+    if (codepoint < startUnicodeValue) return -1;
+    if (codepoint > startUnicodeValue + additionalCount) return +1;
+    return 0;
+  }
+
+  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);
+};
+
+struct DefaultUVS : SortedArray32Of<UnicodeValueRange>
+{
+  void collect_unicodes (hb_set_t *out) const
+  {
+    unsigned int count = len;
+    for (unsigned int i = 0; i < count; i++)
+    {
+      hb_codepoint_t first = arrayZ[i].startUnicodeValue;
+      hb_codepoint_t last = hb_min ((hb_codepoint_t) (first + arrayZ[i].additionalCount),
+				    (hb_codepoint_t) HB_UNICODE_MAX);
+      out->add_range (first, last);
+    }
+  }
+
+  DefaultUVS* copy (hb_serialize_context_t *c,
+		    const hb_set_t *unicodes) const
+  {
+    DefaultUVS *out = c->start_embed<DefaultUVS> ();
+    if (unlikely (!out)) return nullptr;
+    auto snap = c->snapshot ();
+
+    HBUINT32 len;
+    len = 0;
+    if (unlikely (!c->copy<HBUINT32> (len))) return nullptr;
+    unsigned init_len = c->length ();
+
+    if (this->len > unicodes->get_population () * hb_bit_storage ((unsigned) this->len))
+    {
+      hb_codepoint_t start = HB_SET_VALUE_INVALID;
+      hb_codepoint_t end = HB_SET_VALUE_INVALID;
+
+      for (hb_codepoint_t u = HB_SET_VALUE_INVALID;
+	   unicodes->next (&u);)
+      {
+        if (!as_array ().bsearch (u))
+	  continue;
+	if (start == HB_SET_VALUE_INVALID)
+	{
+	  start = u;
+	  end = start - 1;
+	}
+	if (end + 1 != u || end - start == 255)
+        {
+	  UnicodeValueRange rec;
+	  rec.startUnicodeValue = start;
+	  rec.additionalCount = end - start;
+	  c->copy<UnicodeValueRange> (rec);
+	  start = u;
+	}
+	end = u;
+      }
+      if (start != HB_SET_VALUE_INVALID)
+      {
+	UnicodeValueRange rec;
+	rec.startUnicodeValue = start;
+	rec.additionalCount = end - start;
+	c->copy<UnicodeValueRange> (rec);
+      }
+
+    }
+    else
+    {
+      hb_codepoint_t lastCode = HB_SET_VALUE_INVALID;
+      int count = -1;
+
+      for (const UnicodeValueRange& _ : *this)
+      {
+	hb_codepoint_t curEntry = (hb_codepoint_t) (_.startUnicodeValue - 1);
+	hb_codepoint_t end = curEntry + _.additionalCount + 2;
+
+	for (; unicodes->next (&curEntry) && curEntry < end;)
+	{
+	  count += 1;
+	  if (lastCode == HB_SET_VALUE_INVALID)
+	    lastCode = curEntry;
+	  else if (lastCode + count != curEntry)
+	  {
+	    UnicodeValueRange rec;
+	    rec.startUnicodeValue = lastCode;
+	    rec.additionalCount = count - 1;
+	    c->copy<UnicodeValueRange> (rec);
+
+	    lastCode = curEntry;
+	    count = 0;
+	  }
+	}
+      }
+
+      if (lastCode != HB_MAP_VALUE_INVALID)
+      {
+	UnicodeValueRange rec;
+	rec.startUnicodeValue = lastCode;
+	rec.additionalCount = count;
+	c->copy<UnicodeValueRange> (rec);
+      }
+    }
+
+    if (c->length () - init_len == 0)
+    {
+      c->revert (snap);
+      return nullptr;
+    }
+    else
+    {
+      if (unlikely (!c->check_assign (out->len,
+                                      (c->length () - init_len) / UnicodeValueRange::static_size,
+                                      HB_SERIALIZE_ERROR_INT_OVERFLOW))) return nullptr;
+      return out;
+    }
+  }
+
+  public:
+  DEFINE_SIZE_ARRAY (4, *this);
+};
+
+struct UVSMapping
+{
+  int cmp (const hb_codepoint_t &codepoint) const
+  { return unicodeValue.cmp (codepoint); }
+
+  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 */
+  HBGlyphID16	glyphID;	/* Glyph ID of the UVS */
+  public:
+  DEFINE_SIZE_STATIC (5);
+};
+
+struct NonDefaultUVS : SortedArray32Of<UVSMapping>
+{
+  void collect_unicodes (hb_set_t *out) const
+  {
+    for (const auto& a : as_array ())
+      out->add (a.unicodeValue);
+  }
+
+  void collect_mapping (hb_set_t *unicodes, /* OUT */
+			hb_map_t *mapping /* OUT */) const
+  {
+    for (const auto& a : as_array ())
+    {
+      hb_codepoint_t unicode = a.unicodeValue;
+      hb_codepoint_t glyphid = a.glyphID;
+      unicodes->add (unicode);
+      mapping->set (unicode, glyphid);
+    }
+  }
+
+  void closure_glyphs (const hb_set_t      *unicodes,
+		       hb_set_t            *glyphset) const
+  {
+    + as_array ()
+    | hb_filter (unicodes, &UVSMapping::unicodeValue)
+    | hb_map (&UVSMapping::glyphID)
+    | hb_sink (glyphset)
+    ;
+  }
+
+  NonDefaultUVS* copy (hb_serialize_context_t *c,
+		       const hb_set_t *unicodes,
+		       const hb_set_t *glyphs_requested,
+		       const hb_map_t *glyph_map) const
+  {
+    NonDefaultUVS *out = c->start_embed<NonDefaultUVS> ();
+    if (unlikely (!out)) return nullptr;
+
+    auto it =
+    + as_array ()
+    | hb_filter ([&] (const UVSMapping& _)
+		 {
+		   return unicodes->has (_.unicodeValue) || glyphs_requested->has (_.glyphID);
+		 })
+    ;
+
+    if (!it) return nullptr;
+
+    HBUINT32 len;
+    len = it.len ();
+    if (unlikely (!c->copy<HBUINT32> (len))) return nullptr;
+
+    for (const UVSMapping& _ : it)
+    {
+      UVSMapping mapping;
+      mapping.unicodeValue = _.unicodeValue;
+      mapping.glyphID = glyph_map->get (_.glyphID);
+      c->copy<UVSMapping> (mapping);
+    }
+
+    return out;
+  }
+
+  public:
+  DEFINE_SIZE_ARRAY (4, *this);
+};
+
+struct VariationSelectorRecord
+{
+  glyph_variant_t get_glyph (hb_codepoint_t codepoint,
+			     hb_codepoint_t *glyph,
+			     const void *base) const
+  {
+    if ((base+defaultUVS).bfind (codepoint))
+      return GLYPH_VARIANT_USE_DEFAULT;
+    const UVSMapping &nonDefault = (base+nonDefaultUVS).bsearch (codepoint);
+    if (nonDefault.glyphID)
+    {
+      *glyph = nonDefault.glyphID;
+       return GLYPH_VARIANT_FOUND;
+    }
+    return GLYPH_VARIANT_NOT_FOUND;
+  }
+
+  VariationSelectorRecord(const VariationSelectorRecord& other)
+  {
+    *this = other;
+  }
+
+  void operator= (const VariationSelectorRecord& other)
+  {
+    varSelector = other.varSelector;
+    HBUINT32 offset = other.defaultUVS;
+    defaultUVS = offset;
+    offset = other.nonDefaultUVS;
+    nonDefaultUVS = offset;
+  }
+
+  void collect_unicodes (hb_set_t *out, const void *base) const
+  {
+    (base+defaultUVS).collect_unicodes (out);
+    (base+nonDefaultUVS).collect_unicodes (out);
+  }
+
+  void collect_mapping (const void *base,
+			hb_set_t *unicodes, /* OUT */
+			hb_map_t *mapping /* OUT */) const
+  {
+    (base+defaultUVS).collect_unicodes (unicodes);
+    (base+nonDefaultUVS).collect_mapping (unicodes, mapping);
+  }
+
+  int cmp (const hb_codepoint_t &variation_selector) const
+  { return varSelector.cmp (variation_selector); }
+
+  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));
+  }
+
+  hb_pair_t<unsigned, unsigned>
+  copy (hb_serialize_context_t *c,
+	const hb_set_t *unicodes,
+	const hb_set_t *glyphs_requested,
+	const hb_map_t *glyph_map,
+	const void *base) const
+  {
+    auto snap = c->snapshot ();
+    auto *out = c->embed<VariationSelectorRecord> (*this);
+    if (unlikely (!out)) return hb_pair (0, 0);
+
+    out->defaultUVS = 0;
+    out->nonDefaultUVS = 0;
+
+    unsigned non_default_uvs_objidx = 0;
+    if (nonDefaultUVS != 0)
+    {
+      c->push ();
+      if (c->copy (base+nonDefaultUVS, unicodes, glyphs_requested, glyph_map))
+	non_default_uvs_objidx = c->pop_pack ();
+      else c->pop_discard ();
+    }
+
+    unsigned default_uvs_objidx = 0;
+    if (defaultUVS != 0)
+    {
+      c->push ();
+      if (c->copy (base+defaultUVS, unicodes))
+	default_uvs_objidx = c->pop_pack ();
+      else c->pop_discard ();
+    }
+
+
+    if (!default_uvs_objidx && !non_default_uvs_objidx)
+      c->revert (snap);
+
+    return hb_pair (default_uvs_objidx, non_default_uvs_objidx);
+  }
+
+  HBUINT24	varSelector;	/* Variation selector. */
+  Offset32To<DefaultUVS>
+		defaultUVS;	/* Offset to Default UVS Table.  May be 0. */
+  Offset32To<NonDefaultUVS>
+		nonDefaultUVS;	/* Offset to Non-Default UVS Table.  May be 0. */
+  public:
+  DEFINE_SIZE_STATIC (11);
+};
+
+struct CmapSubtableFormat14
+{
+  glyph_variant_t get_glyph_variant (hb_codepoint_t codepoint,
+				     hb_codepoint_t variation_selector,
+				     hb_codepoint_t *glyph) const
+  { return record.bsearch (variation_selector).get_glyph (codepoint, glyph, this); }
+
+  void collect_variation_selectors (hb_set_t *out) const
+  {
+    for (const auto& a : record.as_array ())
+      out->add (a.varSelector);
+  }
+  void collect_variation_unicodes (hb_codepoint_t variation_selector,
+				   hb_set_t *out) const
+  { record.bsearch (variation_selector).collect_unicodes (out, this); }
+
+  void serialize (hb_serialize_context_t *c,
+		  const hb_set_t *unicodes,
+		  const hb_set_t *glyphs_requested,
+		  const hb_map_t *glyph_map,
+		  const void *base)
+  {
+    auto snap = c->snapshot ();
+    unsigned table_initpos = c->length ();
+    const char* init_tail = c->tail;
+
+    if (unlikely (!c->extend_min (this))) return;
+    this->format = 14;
+
+    auto src_tbl = reinterpret_cast<const CmapSubtableFormat14*> (base);
+
+    /*
+     * Some versions of OTS require that offsets are in order. Due to the use
+     * of push()/pop_pack() serializing the variation records in order results
+     * in the offsets being in reverse order (first record has the largest
+     * offset). While this is perfectly valid, it will cause some versions of
+     * OTS to consider this table bad.
+     *
+     * So to prevent this issue we serialize the variation records in reverse
+     * order, so that the offsets are ordered from small to large. Since
+     * variation records are supposed to be in increasing order of varSelector
+     * we then have to reverse the order of the written variation selector
+     * records after everything is finalized.
+     */
+    hb_vector_t<hb_pair_t<unsigned, unsigned>> obj_indices;
+    for (int i = src_tbl->record.len - 1; i >= 0; i--)
+    {
+      hb_pair_t<unsigned, unsigned> result = src_tbl->record[i].copy (c, unicodes, glyphs_requested, glyph_map, base);
+      if (result.first || result.second)
+	obj_indices.push (result);
+    }
+
+    if (c->length () - table_initpos == CmapSubtableFormat14::min_size)
+    {
+      c->revert (snap);
+      return;
+    }
+
+    if (unlikely (!c->check_success (!obj_indices.in_error ())))
+      return;
+
+    int tail_len = init_tail - c->tail;
+    c->check_assign (this->length, c->length () - table_initpos + tail_len,
+                     HB_SERIALIZE_ERROR_INT_OVERFLOW);
+    c->check_assign (this->record.len,
+		     (c->length () - table_initpos - CmapSubtableFormat14::min_size) /
+		     VariationSelectorRecord::static_size,
+                     HB_SERIALIZE_ERROR_INT_OVERFLOW);
+
+    /* Correct the incorrect write order by reversing the order of the variation
+       records array. */
+    _reverse_variation_records ();
+
+    /* Now that records are in the right order, we can set up the offsets. */
+    _add_links_to_variation_records (c, obj_indices);
+  }
+
+  void _reverse_variation_records ()
+  {
+    record.as_array ().reverse ();
+  }
+
+  void _add_links_to_variation_records (hb_serialize_context_t *c,
+					const hb_vector_t<hb_pair_t<unsigned, unsigned>>& obj_indices)
+  {
+    for (unsigned i = 0; i < obj_indices.length; i++)
+    {
+      /*
+       * Since the record array has been reversed (see comments in copy())
+       * but obj_indices has not been, the indices at obj_indices[i]
+       * are for the variation record at record[j].
+       */
+      int j = obj_indices.length - 1 - i;
+      c->add_link (record[j].defaultUVS, obj_indices[i].first);
+      c->add_link (record[j].nonDefaultUVS, obj_indices[i].second);
+    }
+  }
+
+  void closure_glyphs (const hb_set_t      *unicodes,
+		       hb_set_t            *glyphset) const
+  {
+    + hb_iter (record)
+    | hb_filter (hb_bool, &VariationSelectorRecord::nonDefaultUVS)
+    | hb_map (&VariationSelectorRecord::nonDefaultUVS)
+    | hb_map (hb_add (this))
+    | hb_apply ([=] (const NonDefaultUVS& _) { _.closure_glyphs (unicodes, glyphset); })
+    ;
+  }
+
+  void collect_unicodes (hb_set_t *out) const
+  {
+    for (const VariationSelectorRecord& _ : record)
+      _.collect_unicodes (out, this);
+  }
+
+  void collect_mapping (hb_set_t *unicodes, /* OUT */
+			hb_map_t *mapping /* OUT */) const
+  {
+    for (const VariationSelectorRecord& _ : record)
+      _.collect_mapping (this, unicodes, mapping);
+  }
+
+  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. */
+  SortedArray32Of<VariationSelectorRecord>
+		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. */
+
+  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;
+    }
+  }
+  void collect_unicodes (hb_set_t *out, unsigned int num_glyphs = UINT_MAX) const
+  {
+    switch (u.format) {
+    case  0: u.format0 .collect_unicodes (out); return;
+    case  4: u.format4 .collect_unicodes (out); return;
+    case  6: u.format6 .collect_unicodes (out); return;
+    case 10: u.format10.collect_unicodes (out); return;
+    case 12: u.format12.collect_unicodes (out, num_glyphs); return;
+    case 13: u.format13.collect_unicodes (out, num_glyphs); return;
+    case 14:
+    default: return;
+    }
+  }
+
+  void collect_mapping (hb_set_t *unicodes, /* OUT */
+			hb_map_t *mapping, /* OUT */
+			unsigned num_glyphs = UINT_MAX) const
+  {
+    switch (u.format) {
+    case  0: u.format0 .collect_mapping (unicodes, mapping); return;
+    case  4: u.format4 .collect_mapping (unicodes, mapping); return;
+    case  6: u.format6 .collect_mapping (unicodes, mapping); return;
+    case 10: u.format10.collect_mapping (unicodes, mapping); return;
+    case 12: u.format12.collect_mapping (unicodes, mapping, num_glyphs); return;
+    case 13: u.format13.collect_mapping (unicodes, mapping, num_glyphs); return;
+    case 14:
+    default: return;
+    }
+  }
+
+  unsigned get_language () const
+  {
+    switch (u.format) {
+    case  0: return u.format0 .get_language ();
+    case  4: return u.format4 .get_language ();
+    case  6: return u.format6 .get_language ();
+    case 10: return u.format10.get_language ();
+    case 12: return u.format12.get_language ();
+    case 13: return u.format13.get_language ();
+    case 14:
+    default: return 0;
+    }
+  }
+
+  template<typename Iterator,
+	   hb_requires (hb_is_iterator (Iterator))>
+  void serialize (hb_serialize_context_t *c,
+		  Iterator it,
+		  unsigned format,
+		  const hb_subset_plan_t *plan,
+		  const void *base)
+  {
+    switch (format) {
+    case  4: return u.format4.serialize (c, it);
+    case 12: return u.format12.serialize (c, it);
+    case 14: return u.format14.serialize (c, plan->unicodes, plan->glyphs_requested, plan->glyph_map, base);
+    default: return;
+    }
+  }
+
+  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
+{
+  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;
+  }
+
+  bool sanitize (hb_sanitize_context_t *c, const void *base) const
+  {
+    TRACE_SANITIZE (this);
+    return_trace (c->check_struct (this) &&
+		  subtable.sanitize (c, base));
+  }
+
+  template<typename Iterator,
+	   hb_requires (hb_is_iterator (Iterator))>
+  EncodingRecord* copy (hb_serialize_context_t *c,
+			Iterator it,
+			unsigned format,
+			const void *base,
+			const hb_subset_plan_t *plan,
+			/* INOUT */ unsigned *objidx) const
+  {
+    TRACE_SERIALIZE (this);
+    auto snap = c->snapshot ();
+    auto *out = c->embed (this);
+    if (unlikely (!out)) return_trace (nullptr);
+    out->subtable = 0;
+
+    if (*objidx == 0)
+    {
+      CmapSubtable *cmapsubtable = c->push<CmapSubtable> ();
+      unsigned origin_length = c->length ();
+      cmapsubtable->serialize (c, it, format, plan, &(base+subtable));
+      if (c->length () - origin_length > 0) *objidx = c->pop_pack ();
+      else c->pop_discard ();
+    }
+
+    if (*objidx == 0)
+    {
+      c->revert (snap);
+      return_trace (nullptr);
+    }
+
+    c->add_link (out->subtable, *objidx);
+    return_trace (out);
+  }
+
+  HBUINT16	platformID;	/* Platform ID. */
+  HBUINT16	encodingID;	/* Platform-specific encoding ID. */
+  Offset32To<CmapSubtable>
+		subtable;	/* Byte offset from beginning of table to the subtable for this encoding. */
+  public:
+  DEFINE_SIZE_STATIC (8);
+};
+
+struct cmap;
+
+struct SubtableUnicodesCache {
+
+ private:
+  hb_blob_ptr_t<cmap> base_blob;
+  const char* base;
+  hb_hashmap_t<unsigned, hb::unique_ptr<hb_set_t>> cached_unicodes;
+
+ public:
+
+  static SubtableUnicodesCache* create (hb_blob_ptr_t<cmap> source_table)
+  {
+    SubtableUnicodesCache* cache =
+        (SubtableUnicodesCache*) hb_malloc (sizeof(SubtableUnicodesCache));
+    new (cache) SubtableUnicodesCache (source_table);
+    return cache;
+  }
+
+  static void destroy (void* value) {
+    if (!value) return;
+
+    SubtableUnicodesCache* cache = (SubtableUnicodesCache*) value;
+    cache->~SubtableUnicodesCache ();
+    hb_free (cache);
+  }
+
+  SubtableUnicodesCache(const void* cmap_base)
+      : base_blob(),
+        base ((const char*) cmap_base),
+        cached_unicodes ()
+  {}
+
+  SubtableUnicodesCache(hb_blob_ptr_t<cmap> base_blob_)
+      : base_blob(base_blob_),
+        base ((const char *) base_blob.get()),
+        cached_unicodes ()
+  {}
+
+  ~SubtableUnicodesCache()
+  {
+    base_blob.destroy ();
+  }
+
+  bool same_base(const void* other) const
+  {
+    return other == (const void*) base;
+  }
+
+  const hb_set_t* set_for (const EncodingRecord* record,
+                           SubtableUnicodesCache& mutable_cache) const
+  {
+    if (cached_unicodes.has ((unsigned) ((const char *) record - base)))
+      return cached_unicodes.get ((unsigned) ((const char *) record - base));
+
+    return mutable_cache.set_for (record);
+  }
+
+  const hb_set_t* set_for (const EncodingRecord* record)
+  {
+    if (!cached_unicodes.has ((unsigned) ((const char *) record - base)))
+    {
+      hb_set_t *s = hb_set_create ();
+      if (unlikely (s->in_error ()))
+	return hb_set_get_empty ();
+
+      (base+record->subtable).collect_unicodes (s);
+
+      if (unlikely (!cached_unicodes.set ((unsigned) ((const char *) record - base), hb::unique_ptr<hb_set_t> {s})))
+        return hb_set_get_empty ();
+
+      return s;
+    }
+    return cached_unicodes.get ((unsigned) ((const char *) record - base));
+  }
+
+};
+
+static inline uint_fast16_t
+_hb_symbol_pua_map (unsigned codepoint)
+{
+  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 0xF000u + codepoint;
+  }
+  return 0;
+}
+
+struct cmap
+{
+  static constexpr hb_tag_t tableTag = HB_OT_TAG_cmap;
+
+
+  static SubtableUnicodesCache* create_filled_cache(hb_blob_ptr_t<cmap> source_table) {
+    const cmap* cmap = source_table.get();
+    auto it =
+    + hb_iter (cmap->encodingRecord)
+    | hb_filter ([&](const EncodingRecord& _) {
+      return cmap::filter_encoding_records_for_subset (cmap, _);
+    })
+    ;
+
+    SubtableUnicodesCache* cache = SubtableUnicodesCache::create(source_table);
+    for (const EncodingRecord& _ : it)
+      cache->set_for(&_); // populate the cache for this encoding record.
+
+    return cache;
+  }
+
+  template<typename Iterator, typename EncodingRecIter,
+	   hb_requires (hb_is_iterator (EncodingRecIter))>
+  bool serialize (hb_serialize_context_t *c,
+		  Iterator it,
+		  EncodingRecIter encodingrec_iter,
+		  const void *base,
+		  hb_subset_plan_t *plan,
+                  bool drop_format_4 = false)
+  {
+    if (unlikely (!c->extend_min ((*this))))  return false;
+    this->version = 0;
+
+    unsigned format4objidx = 0, format12objidx = 0, format14objidx = 0;
+    auto snap = c->snapshot ();
+
+    SubtableUnicodesCache local_unicodes_cache (base);
+    const SubtableUnicodesCache* unicodes_cache = &local_unicodes_cache;
+
+    if (plan->accelerator &&
+        plan->accelerator->cmap_cache &&
+        plan->accelerator->cmap_cache->same_base (base))
+      unicodes_cache = plan->accelerator->cmap_cache;
+
+    for (const EncodingRecord& _ : encodingrec_iter)
+    {
+      if (c->in_error ())
+        return false;
+
+      unsigned format = (base+_.subtable).u.format;
+      if (format != 4 && format != 12 && format != 14) continue;
+
+      const hb_set_t* unicodes_set = unicodes_cache->set_for (&_, local_unicodes_cache);
+
+      if (!drop_format_4 && format == 4)
+      {
+        c->copy (_, + it | hb_filter (*unicodes_set, hb_first), 4u, base, plan, &format4objidx);
+        if (c->in_error () && c->only_overflow ())
+        {
+          // cmap4 overflowed, reset and retry serialization without format 4 subtables.
+          c->revert (snap);
+          return serialize (c, it,
+                            encodingrec_iter,
+                            base,
+                            plan,
+                            true);
+        }
+      }
+
+      else if (format == 12)
+      {
+        if (_can_drop (_,
+                       *unicodes_set,
+                       base,
+                       *unicodes_cache,
+                       local_unicodes_cache,
+                       + it | hb_map (hb_first), encodingrec_iter))
+          continue;
+        c->copy (_, + it | hb_filter (*unicodes_set, hb_first), 12u, base, plan, &format12objidx);
+      }
+      else if (format == 14) c->copy (_, it, 14u, base, plan, &format14objidx);
+    }
+    c->check_assign(this->encodingRecord.len,
+                    (c->length () - cmap::min_size)/EncodingRecord::static_size,
+                    HB_SERIALIZE_ERROR_INT_OVERFLOW);
+
+    // Fail if format 4 was dropped and there is no cmap12.
+    return !drop_format_4 || format12objidx;
+  }
+
+  template<typename Iterator, typename EncodingRecordIterator,
+      hb_requires (hb_is_iterator (Iterator)),
+      hb_requires (hb_is_iterator (EncodingRecordIterator))>
+  bool _can_drop (const EncodingRecord& cmap12,
+                  const hb_set_t& cmap12_unicodes,
+                  const void* base,
+                  const SubtableUnicodesCache& unicodes_cache,
+                  SubtableUnicodesCache& local_unicodes_cache,
+                  Iterator subset_unicodes,
+                  EncodingRecordIterator encoding_records)
+  {
+    for (auto cp : + subset_unicodes | hb_filter (cmap12_unicodes))
+    {
+      if (cp >= 0x10000) return false;
+    }
+
+    unsigned target_platform;
+    unsigned target_encoding;
+    unsigned target_language = (base+cmap12.subtable).get_language ();
+
+    if (cmap12.platformID == 0 && cmap12.encodingID == 4)
+    {
+      target_platform = 0;
+      target_encoding = 3;
+    } else if (cmap12.platformID == 3 && cmap12.encodingID == 10) {
+      target_platform = 3;
+      target_encoding = 1;
+    } else {
+      return false;
+    }
+
+    for (const auto& _ : encoding_records)
+    {
+      if (_.platformID != target_platform
+          || _.encodingID != target_encoding
+          || (base+_.subtable).get_language() != target_language)
+        continue;
+
+      const hb_set_t* sibling_unicodes = unicodes_cache.set_for (&_, local_unicodes_cache);
+
+      auto cmap12 = + subset_unicodes | hb_filter (cmap12_unicodes);
+      auto sibling = + subset_unicodes | hb_filter (*sibling_unicodes);
+      for (; cmap12 && sibling; cmap12++, sibling++)
+      {
+        unsigned a = *cmap12;
+        unsigned b = *sibling;
+        if (a != b) return false;
+      }
+
+      return !cmap12 && !sibling;
+    }
+
+    return false;
+  }
+
+  void closure_glyphs (const hb_set_t      *unicodes,
+		       hb_set_t            *glyphset) const
+  {
+    + hb_iter (encodingRecord)
+    | hb_map (&EncodingRecord::subtable)
+    | hb_map (hb_add (this))
+    | hb_filter ([&] (const CmapSubtable& _) { return _.u.format == 14; })
+    | hb_apply ([=] (const CmapSubtable& _) { _.u.format14.closure_glyphs (unicodes, glyphset); })
+    ;
+  }
+
+  bool subset (hb_subset_context_t *c) const
+  {
+    TRACE_SUBSET (this);
+
+    cmap *cmap_prime = c->serializer->start_embed<cmap> ();
+    if (unlikely (!c->serializer->check_success (cmap_prime))) return_trace (false);
+
+    auto encodingrec_iter =
+    + hb_iter (encodingRecord)
+    | hb_filter ([&](const EncodingRecord& _) {
+      return cmap::filter_encoding_records_for_subset (this, _);
+    })
+    ;
+
+    if (unlikely (!encodingrec_iter.len ())) return_trace (false);
+
+    const EncodingRecord *unicode_bmp= nullptr, *unicode_ucs4 = nullptr, *ms_bmp = nullptr, *ms_ucs4 = nullptr;
+    bool has_format12 = false;
+
+    for (const EncodingRecord& _ : encodingrec_iter)
+    {
+      unsigned format = (this + _.subtable).u.format;
+      if (format == 12) has_format12 = true;
+
+      const EncodingRecord *table = std::addressof (_);
+      if      (_.platformID == 0 && _.encodingID ==  3) unicode_bmp = table;
+      else if (_.platformID == 0 && _.encodingID ==  4) unicode_ucs4 = table;
+      else if (_.platformID == 3 && _.encodingID ==  1) ms_bmp = table;
+      else if (_.platformID == 3 && _.encodingID == 10) ms_ucs4 = table;
+    }
+
+    if (unlikely (!has_format12 && !unicode_bmp && !ms_bmp)) return_trace (false);
+    if (unlikely (has_format12 && (!unicode_ucs4 && !ms_ucs4))) return_trace (false);
+
+    auto it =
+    + c->plan->unicode_to_new_gid_list.iter ()
+    | hb_filter ([&] (const hb_pair_t<hb_codepoint_t, hb_codepoint_t> _)
+		 { return (_.second != HB_MAP_VALUE_INVALID); })
+    ;
+
+    return_trace (cmap_prime->serialize (c->serializer,
+                                         it,
+                                         encodingrec_iter,
+                                         this,
+                                         c->plan));
+  }
+
+  const CmapSubtable *find_best_subtable (bool *symbol = nullptr) const
+  {
+    if (symbol) *symbol = false;
+
+    const CmapSubtable *subtable;
+
+    /* Symbol subtable.
+     * Prefer symbol if available.
+     * https://github.com/harfbuzz/harfbuzz/issues/1918 */
+    if ((subtable = this->find_subtable (3, 0)))
+    {
+      if (symbol) *symbol = true;
+      return subtable;
+    }
+
+    /* 32-bit subtables. */
+    if ((subtable = this->find_subtable (3, 10))) return subtable;
+    if ((subtable = this->find_subtable (0, 6))) return subtable;
+    if ((subtable = this->find_subtable (0, 4))) return subtable;
+
+    /* 16-bit subtables. */
+    if ((subtable = this->find_subtable (3, 1))) return subtable;
+    if ((subtable = this->find_subtable (0, 3))) return subtable;
+    if ((subtable = this->find_subtable (0, 2))) return subtable;
+    if ((subtable = this->find_subtable (0, 1))) return subtable;
+    if ((subtable = this->find_subtable (0, 0))) return subtable;
+
+    /* Meh. */
+    return &Null (CmapSubtable);
+  }
+
+  struct accelerator_t
+  {
+    accelerator_t (hb_face_t *face)
+    {
+      this->table = hb_sanitize_context_t ().reference_table<cmap> (face);
+      bool symbol;
+      this->subtable = table->find_best_subtable (&symbol);
+      this->subtable_uvs = &Null (CmapSubtableFormat14);
+      {
+	const CmapSubtable *st = table->find_subtable (0, 5);
+	if (st && st->u.format == 14)
+	  subtable_uvs = &st->u.format14;
+      }
+
+      this->get_glyph_data = subtable;
+      if (unlikely (symbol))
+      {
+	switch ((unsigned) face->table.OS2->get_font_page ()) {
+	case OS2::font_page_t::FONT_PAGE_NONE:
+	  this->get_glyph_funcZ = get_glyph_from_symbol<CmapSubtable, _hb_symbol_pua_map>;
+	  break;
+#ifndef HB_NO_OT_SHAPER_ARABIC_FALLBACK
+	case OS2::font_page_t::FONT_PAGE_SIMP_ARABIC:
+	  this->get_glyph_funcZ = get_glyph_from_symbol<CmapSubtable, _hb_arabic_pua_simp_map>;
+	  break;
+	case OS2::font_page_t::FONT_PAGE_TRAD_ARABIC:
+	  this->get_glyph_funcZ = get_glyph_from_symbol<CmapSubtable, _hb_arabic_pua_trad_map>;
+	  break;
+#endif
+	default:
+	  this->get_glyph_funcZ = get_glyph_from<CmapSubtable>;
+	  break;
+	}
+      }
+      else
+      {
+	switch (subtable->u.format) {
+	/* Accelerate format 4 and format 12. */
+	default:
+	  this->get_glyph_funcZ = get_glyph_from<CmapSubtable>;
+	  break;
+	case 12:
+	  this->get_glyph_funcZ = get_glyph_from<CmapSubtableFormat12>;
+	  break;
+	case  4:
+	{
+	  this->format4_accel.init (&subtable->u.format4);
+	  this->get_glyph_data = &this->format4_accel;
+	  this->get_glyph_funcZ = this->format4_accel.get_glyph_func;
+	  break;
+	}
+	}
+      }
+    }
+    ~accelerator_t () { this->table.destroy (); }
+
+    bool get_nominal_glyph (hb_codepoint_t  unicode,
+			    hb_codepoint_t *glyph) const
+    {
+      if (unlikely (!this->get_glyph_funcZ)) return false;
+      return this->get_glyph_funcZ (this->get_glyph_data, unicode, glyph);
+    }
+    unsigned int get_nominal_glyphs (unsigned int count,
+				     const hb_codepoint_t *first_unicode,
+				     unsigned int unicode_stride,
+				     hb_codepoint_t *first_glyph,
+				     unsigned int glyph_stride) const
+    {
+      if (unlikely (!this->get_glyph_funcZ)) return 0;
+
+      hb_cmap_get_glyph_func_t get_glyph_funcZ = this->get_glyph_funcZ;
+      const void *get_glyph_data = this->get_glyph_data;
+
+      unsigned int done;
+      for (done = 0;
+	   done < count && get_glyph_funcZ (get_glyph_data, *first_unicode, first_glyph);
+	   done++)
+      {
+	first_unicode = &StructAtOffsetUnaligned<hb_codepoint_t> (first_unicode, unicode_stride);
+	first_glyph = &StructAtOffsetUnaligned<hb_codepoint_t> (first_glyph, glyph_stride);
+      }
+      return done;
+    }
+
+    bool get_variation_glyph (hb_codepoint_t  unicode,
+			      hb_codepoint_t  variation_selector,
+			      hb_codepoint_t *glyph) const
+    {
+      switch (this->subtable_uvs->get_glyph_variant (unicode,
+						     variation_selector,
+						     glyph))
+      {
+	case GLYPH_VARIANT_NOT_FOUND:	return false;
+	case GLYPH_VARIANT_FOUND:	return true;
+	case GLYPH_VARIANT_USE_DEFAULT:	break;
+      }
+
+      return get_nominal_glyph (unicode, glyph);
+    }
+
+    void collect_unicodes (hb_set_t *out, unsigned int num_glyphs) const
+    { subtable->collect_unicodes (out, num_glyphs); }
+    void collect_mapping (hb_set_t *unicodes, hb_map_t *mapping,
+			  unsigned num_glyphs = UINT_MAX) const
+    { subtable->collect_mapping (unicodes, mapping, num_glyphs); }
+    void collect_variation_selectors (hb_set_t *out) const
+    { subtable_uvs->collect_variation_selectors (out); }
+    void collect_variation_unicodes (hb_codepoint_t variation_selector,
+				     hb_set_t *out) const
+    { subtable_uvs->collect_variation_unicodes (variation_selector, out); }
+
+    protected:
+    typedef bool (*hb_cmap_get_glyph_func_t) (const void *obj,
+					      hb_codepoint_t codepoint,
+					      hb_codepoint_t *glyph);
+    typedef uint_fast16_t (*hb_pua_remap_func_t) (unsigned);
+
+    template <typename Type>
+    HB_INTERNAL static 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, hb_pua_remap_func_t remap>
+    HB_INTERNAL static 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 (hb_codepoint_t c = remap (codepoint))
+	return typed_obj->get_glyph (c, glyph);
+
+      return false;
+    }
+
+    private:
+    hb_nonnull_ptr_t<const CmapSubtable> subtable;
+    hb_nonnull_ptr_t<const CmapSubtableFormat14> subtable_uvs;
+
+    hb_cmap_get_glyph_func_t get_glyph_funcZ;
+    const void *get_glyph_data;
+
+    CmapSubtableFormat4::accelerator_t format4_accel;
+
+    public:
+    hb_blob_ptr_t<cmap> table;
+  };
+
+  protected:
+
+  const CmapSubtable *find_subtable (unsigned int platform_id,
+				     unsigned int encoding_id) const
+  {
+    EncodingRecord key;
+    key.platformID = platform_id;
+    key.encodingID = encoding_id;
+
+    const EncodingRecord &result = encodingRecord.bsearch (key);
+    if (!result.subtable)
+      return nullptr;
+
+    return &(this+result.subtable);
+  }
+
+  const EncodingRecord *find_encodingrec (unsigned int platform_id,
+					  unsigned int encoding_id) const
+  {
+    EncodingRecord key;
+    key.platformID = platform_id;
+    key.encodingID = encoding_id;
+
+    return encodingRecord.as_array ().bsearch (key);
+  }
+
+  bool find_subtable (unsigned format) const
+  {
+    auto it =
+    + hb_iter (encodingRecord)
+    | hb_map (&EncodingRecord::subtable)
+    | hb_map (hb_add (this))
+    | hb_filter ([&] (const CmapSubtable& _) { return _.u.format == format; })
+    ;
+
+    return it.len ();
+  }
+
+  public:
+
+  bool sanitize (hb_sanitize_context_t *c) const
+  {
+    TRACE_SANITIZE (this);
+    return_trace (c->check_struct (this) &&
+		  likely (version == 0) &&
+		  encodingRecord.sanitize (c, this));
+  }
+
+ private:
+
+  static bool filter_encoding_records_for_subset(const cmap* cmap,
+                                                 const EncodingRecord& _)
+  {
+    return
+        (_.platformID == 0 && _.encodingID == 3) ||
+        (_.platformID == 0 && _.encodingID == 4) ||
+        (_.platformID == 3 && _.encodingID == 1) ||
+        (_.platformID == 3 && _.encodingID == 10) ||
+        (cmap + _.subtable).u.format == 14;
+  }
+
+  protected:
+  HBUINT16	version;	/* Table version number (0). */
+  SortedArray16Of<EncodingRecord>
+		encodingRecord;	/* Encoding tables. */
+  public:
+  DEFINE_SIZE_ARRAY (4, encodingRecord);
+};
+
+struct cmap_accelerator_t : cmap::accelerator_t {
+  cmap_accelerator_t (hb_face_t *face) : cmap::accelerator_t (face) {}
+};
+
+} /* namespace OT */
+
+
+#endif /* HB_OT_CMAP_TABLE_HH */