--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mupdf-source/thirdparty/harfbuzz/src/hb-ot-hmtx-table.hh	Mon Sep 15 11:43:07 2025 +0200
@@ -0,0 +1,409 @@
+/*
+ * Copyright © 2011,2012  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, Roderick Sheeter
+ */
+
+#ifndef HB_OT_HMTX_TABLE_HH
+#define HB_OT_HMTX_TABLE_HH
+
+#include "hb-open-type.hh"
+#include "hb-ot-maxp-table.hh"
+#include "hb-ot-hhea-table.hh"
+#include "hb-ot-var-hvar-table.hh"
+#include "hb-ot-metrics.hh"
+
+/*
+ * hmtx -- Horizontal Metrics
+ * https://docs.microsoft.com/en-us/typography/opentype/spec/hmtx
+ * vmtx -- Vertical Metrics
+ * https://docs.microsoft.com/en-us/typography/opentype/spec/vmtx
+ */
+#define HB_OT_TAG_hmtx HB_TAG('h','m','t','x')
+#define HB_OT_TAG_vmtx HB_TAG('v','m','t','x')
+
+
+HB_INTERNAL bool
+_glyf_get_leading_bearing_with_var_unscaled (hb_font_t *font, hb_codepoint_t glyph, bool is_vertical, int *lsb);
+
+HB_INTERNAL unsigned
+_glyf_get_advance_with_var_unscaled (hb_font_t *font, hb_codepoint_t glyph, bool is_vertical);
+
+
+namespace OT {
+
+
+struct LongMetric
+{
+  UFWORD	advance; /* Advance width/height. */
+  FWORD		sb; /* Leading (left/top) side bearing. */
+  public:
+  DEFINE_SIZE_STATIC (4);
+};
+
+
+template <typename T/*Data table type*/, typename H/*Header table type*/, typename V/*Var table type*/>
+struct hmtxvmtx
+{
+  bool sanitize (hb_sanitize_context_t *c HB_UNUSED) const
+  {
+    TRACE_SANITIZE (this);
+    /* We don't check for anything specific here.  The users of the
+     * struct do all the hard work... */
+    return_trace (true);
+  }
+
+  const hb_hashmap_t<unsigned, hb_pair_t<unsigned, int>>* get_mtx_map (const hb_subset_plan_t *plan) const
+  { return T::is_horizontal ? plan->hmtx_map : plan->vmtx_map; }
+
+  bool subset_update_header (hb_subset_plan_t *plan,
+			     unsigned int num_hmetrics) const
+  {
+    hb_blob_t *src_blob = hb_sanitize_context_t ().reference_table<H> (plan->source, H::tableTag);
+    hb_blob_t *dest_blob = hb_blob_copy_writable_or_fail (src_blob);
+    hb_blob_destroy (src_blob);
+
+    if (unlikely (!dest_blob)) {
+      return false;
+    }
+
+    unsigned int length;
+    H *table = (H *) hb_blob_get_data (dest_blob, &length);
+    table->numberOfLongMetrics = num_hmetrics;
+
+    bool result = plan->add_table (H::tableTag, dest_blob);
+    hb_blob_destroy (dest_blob);
+
+    return result;
+  }
+
+  template<typename Iterator,
+	   hb_requires (hb_is_iterator (Iterator))>
+  void serialize (hb_serialize_context_t *c,
+		  Iterator it,
+		  unsigned num_long_metrics)
+  {
+    unsigned idx = 0;
+    for (auto _ : it)
+    {
+      if (idx < num_long_metrics)
+      {
+	LongMetric lm;
+	lm.advance = _.first;
+	lm.sb = _.second;
+	if (unlikely (!c->embed<LongMetric> (&lm))) return;
+      }
+      else
+      {
+	FWORD *sb = c->allocate_size<FWORD> (FWORD::static_size);
+	if (unlikely (!sb)) return;
+	*sb = _.second;
+      }
+      idx++;
+    }
+  }
+
+  bool subset (hb_subset_context_t *c) const
+  {
+    TRACE_SUBSET (this);
+
+    T *table_prime = c->serializer->start_embed <T> ();
+    if (unlikely (!table_prime)) return_trace (false);
+
+    accelerator_t _mtx (c->plan->source);
+    unsigned num_long_metrics;
+    const hb_hashmap_t<unsigned, hb_pair_t<unsigned, int>> *mtx_map = get_mtx_map (c->plan);
+    {
+      /* Determine num_long_metrics to encode. */
+      auto& plan = c->plan;
+
+      num_long_metrics = plan->num_output_glyphs ();
+      unsigned int last_advance = get_new_gid_advance_unscaled (plan, mtx_map, num_long_metrics - 1, _mtx);
+      while (num_long_metrics > 1 &&
+	     last_advance == get_new_gid_advance_unscaled (plan, mtx_map, num_long_metrics - 2, _mtx))
+      {
+	num_long_metrics--;
+      }
+    }
+
+    auto it =
+    + hb_range (c->plan->num_output_glyphs ())
+    | hb_map ([c, &_mtx, mtx_map] (unsigned _)
+	      {
+		if (!mtx_map->has (_))
+		{
+		  hb_codepoint_t old_gid;
+		  if (!c->plan->old_gid_for_new_gid (_, &old_gid))
+		    return hb_pair (0u, 0);
+		  int lsb = 0;
+		  (void) _mtx.get_leading_bearing_without_var_unscaled (old_gid, &lsb);
+		  return hb_pair (_mtx.get_advance_without_var_unscaled (old_gid), +lsb);
+		}
+		return mtx_map->get (_);
+	      })
+    ;
+
+    table_prime->serialize (c->serializer, it, num_long_metrics);
+
+    if (unlikely (c->serializer->in_error ()))
+      return_trace (false);
+
+    // Amend header num hmetrics
+    if (unlikely (!subset_update_header (c->plan, num_long_metrics)))
+      return_trace (false);
+
+    return_trace (true);
+  }
+
+  struct accelerator_t
+  {
+    friend struct hmtxvmtx;
+
+    accelerator_t (hb_face_t *face)
+    {
+      table = hb_sanitize_context_t ().reference_table<hmtxvmtx> (face, T::tableTag);
+      var_table = hb_sanitize_context_t ().reference_table<V> (face, T::variationsTag);
+
+      default_advance = T::is_horizontal ? hb_face_get_upem (face) / 2 : hb_face_get_upem (face);
+
+      /* Populate count variables and sort them out as we go */
+
+      unsigned int len = table.get_length ();
+      if (len & 1)
+        len--;
+
+      num_long_metrics = T::is_horizontal ?
+			 face->table.hhea->numberOfLongMetrics :
+#ifndef HB_NO_VERTICAL
+			 face->table.vhea->numberOfLongMetrics
+#else
+			 0
+#endif
+			 ;
+      if (unlikely (num_long_metrics * 4 > len))
+	num_long_metrics = len / 4;
+      len -= num_long_metrics * 4;
+
+      num_bearings = face->table.maxp->get_num_glyphs ();
+
+      if (unlikely (num_bearings < num_long_metrics))
+        num_bearings = num_long_metrics;
+      if (unlikely ((num_bearings - num_long_metrics) * 2 > len))
+        num_bearings = num_long_metrics + len / 2;
+      len -= (num_bearings - num_long_metrics) * 2;
+
+      /* We MUST set num_bearings to zero if num_long_metrics is zero.
+       * Our get_advance() depends on that. */
+      if (unlikely (!num_long_metrics))
+	num_bearings = num_long_metrics = 0;
+
+      num_advances = num_bearings + len / 2;
+      num_glyphs = face->get_num_glyphs ();
+      if (num_glyphs < num_advances)
+        num_glyphs = num_advances;
+    }
+    ~accelerator_t ()
+    {
+      table.destroy ();
+      var_table.destroy ();
+    }
+
+    bool has_data () const { return (bool) num_bearings; }
+
+    bool get_leading_bearing_without_var_unscaled (hb_codepoint_t glyph,
+						   int *lsb) const
+    {
+      if (glyph < num_long_metrics)
+      {
+	*lsb = table->longMetricZ[glyph].sb;
+	return true;
+      }
+
+      if (unlikely (glyph >= num_bearings))
+	return false;
+
+      const FWORD *bearings = (const FWORD *) &table->longMetricZ[num_long_metrics];
+      *lsb = bearings[glyph - num_long_metrics];
+      return true;
+    }
+
+    bool get_leading_bearing_with_var_unscaled (hb_font_t *font,
+						hb_codepoint_t glyph,
+						int *lsb) const
+    {
+      if (!font->num_coords)
+	return get_leading_bearing_without_var_unscaled (glyph, lsb);
+
+#ifndef HB_NO_VAR
+      float delta;
+      if (var_table->get_lsb_delta_unscaled (glyph, font->coords, font->num_coords, &delta) &&
+	  get_leading_bearing_without_var_unscaled (glyph, lsb))
+      {
+	*lsb += roundf (delta);
+	return true;
+      }
+
+      return _glyf_get_leading_bearing_with_var_unscaled (font, glyph, T::tableTag == HB_OT_TAG_vmtx, lsb);
+#else
+      return false;
+#endif
+    }
+
+    unsigned int get_advance_without_var_unscaled (hb_codepoint_t glyph) const
+    {
+      /* OpenType case. */
+      if (glyph < num_bearings)
+	return table->longMetricZ[hb_min (glyph, (uint32_t) num_long_metrics - 1)].advance;
+
+      /* If num_advances is zero, it means we don't have the metrics table
+       * for this direction: return default advance.  Otherwise, there's a
+       * well-defined answer. */
+      if (unlikely (!num_advances))
+	return default_advance;
+
+#ifdef HB_NO_BEYOND_64K
+      return 0;
+#endif
+
+      if (unlikely (glyph >= num_glyphs))
+        return 0;
+
+      /* num_bearings <= glyph < num_glyphs;
+       * num_bearings <= num_advances */
+
+      /* TODO Optimize */
+
+      if (num_bearings == num_advances)
+        return get_advance_without_var_unscaled (num_bearings - 1);
+
+      const FWORD *bearings = (const FWORD *) &table->longMetricZ[num_long_metrics];
+      const UFWORD *advances = (const UFWORD *) &bearings[num_bearings - num_long_metrics];
+
+      return advances[hb_min (glyph - num_bearings, num_advances - num_bearings - 1)];
+    }
+
+    unsigned get_advance_with_var_unscaled (hb_codepoint_t  glyph,
+					    hb_font_t      *font,
+					    VariationStore::cache_t *store_cache = nullptr) const
+    {
+      unsigned int advance = get_advance_without_var_unscaled (glyph);
+
+#ifndef HB_NO_VAR
+      if (unlikely (glyph >= num_bearings) || !font->num_coords)
+	return advance;
+
+      if (var_table.get_length ())
+	return advance + roundf (var_table->get_advance_delta_unscaled (glyph,
+									font->coords, font->num_coords,
+									store_cache)); // TODO Optimize?!
+
+      return _glyf_get_advance_with_var_unscaled (font, glyph, T::tableTag == HB_OT_TAG_vmtx);
+#else
+      return advance;
+#endif
+    }
+
+    protected:
+    // 0 <= num_long_metrics <= num_bearings <= num_advances <= num_glyphs
+    unsigned num_long_metrics;
+    unsigned num_bearings;
+    unsigned num_advances;
+    unsigned num_glyphs;
+
+    unsigned int default_advance;
+
+    public:
+    hb_blob_ptr_t<hmtxvmtx> table;
+    hb_blob_ptr_t<V> var_table;
+  };
+
+  /* get advance: when no variations, call get_advance_without_var_unscaled.
+   * when there're variations, get advance value from mtx_map in subset_plan*/
+  unsigned get_new_gid_advance_unscaled (const hb_subset_plan_t *plan,
+                                         const hb_hashmap_t<unsigned, hb_pair_t<unsigned, int>> *mtx_map,
+                                         unsigned new_gid,
+                                         const accelerator_t &_mtx) const
+  {
+    if (mtx_map->is_empty () ||
+        (new_gid == 0 && !mtx_map->has (new_gid)))
+    {
+      hb_codepoint_t old_gid = 0;
+      return plan->old_gid_for_new_gid (new_gid, &old_gid) ?
+             _mtx.get_advance_without_var_unscaled (old_gid) : 0;
+    }
+    else
+    { return mtx_map->get (new_gid).first; }
+  }
+
+  protected:
+  UnsizedArrayOf<LongMetric>
+		longMetricZ;	/* Paired advance width and leading
+				 * bearing values for each glyph. The
+				 * value numOfHMetrics comes from
+				 * the 'hhea' table. If the font is
+				 * monospaced, only one entry need
+				 * be in the array, but that entry is
+				 * required. The last entry applies to
+				 * all subsequent glyphs. */
+/*UnsizedArrayOf<FWORD>	leadingBearingX;*/
+				/* Here the advance is assumed
+				 * to be the same as the advance
+				 * for the last entry above. The
+				 * number of entries in this array is
+				 * derived from numGlyphs (from 'maxp'
+				 * table) minus numberOfLongMetrics.
+				 * This generally is used with a run
+				 * of monospaced glyphs (e.g., Kanji
+				 * fonts or Courier fonts). Only one
+				 * run is allowed and it must be at
+				 * the end. This allows a monospaced
+				 * font to vary the side bearing
+				 * values for each glyph. */
+/*UnsizedArrayOf<UFWORD>advancesX;*/
+				/* TODO Document. */
+  public:
+  DEFINE_SIZE_ARRAY (0, longMetricZ);
+};
+
+struct hmtx : hmtxvmtx<hmtx, hhea, HVAR> {
+  static constexpr hb_tag_t tableTag = HB_OT_TAG_hmtx;
+  static constexpr hb_tag_t variationsTag = HB_OT_TAG_HVAR;
+  static constexpr bool is_horizontal = true;
+};
+struct vmtx : hmtxvmtx<vmtx, vhea, VVAR> {
+  static constexpr hb_tag_t tableTag = HB_OT_TAG_vmtx;
+  static constexpr hb_tag_t variationsTag = HB_OT_TAG_VVAR;
+  static constexpr bool is_horizontal = false;
+};
+
+struct hmtx_accelerator_t : hmtx::accelerator_t {
+  hmtx_accelerator_t (hb_face_t *face) : hmtx::accelerator_t (face) {}
+};
+struct vmtx_accelerator_t : vmtx::accelerator_t {
+  vmtx_accelerator_t (hb_face_t *face) : vmtx::accelerator_t (face) {}
+};
+
+} /* namespace OT */
+
+
+#endif /* HB_OT_HMTX_TABLE_HH */