--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mupdf-source/thirdparty/harfbuzz/src/OT/Layout/GSUB/AlternateSubstFormat1.hh	Mon Sep 15 11:43:07 2025 +0200
@@ -0,0 +1,128 @@
+#ifndef OT_LAYOUT_GSUB_ALTERNATESUBSTFORMAT1_HH
+#define OT_LAYOUT_GSUB_ALTERNATESUBSTFORMAT1_HH
+
+#include "AlternateSet.hh"
+#include "Common.hh"
+
+namespace OT {
+namespace Layout {
+namespace GSUB_impl {
+
+template <typename Types>
+struct AlternateSubstFormat1_2
+{
+  protected:
+  HBUINT16      format;                 /* Format identifier--format = 1 */
+  typename Types::template OffsetTo<Coverage>
+                coverage;               /* Offset to Coverage table--from
+                                         * beginning of Substitution table */
+  Array16Of<typename Types::template OffsetTo<AlternateSet<Types>>>
+                alternateSet;           /* Array of AlternateSet tables
+                                         * ordered by Coverage Index */
+  public:
+  DEFINE_SIZE_ARRAY (2 + 2 * Types::size, alternateSet);
+
+  bool sanitize (hb_sanitize_context_t *c) const
+  {
+    TRACE_SANITIZE (this);
+    return_trace (coverage.sanitize (c, this) && alternateSet.sanitize (c, this));
+  }
+
+  bool intersects (const hb_set_t *glyphs) const
+  { return (this+coverage).intersects (glyphs); }
+
+  bool may_have_non_1to1 () const
+  { return false; }
+
+  void closure (hb_closure_context_t *c) const
+  {
+    + hb_zip (this+coverage, alternateSet)
+    | hb_filter (c->parent_active_glyphs (), hb_first)
+    | hb_map (hb_second)
+    | hb_map (hb_add (this))
+    | hb_apply ([c] (const AlternateSet<Types> &_) { _.closure (c); })
+    ;
+  }
+
+  void closure_lookups (hb_closure_lookups_context_t *c) const {}
+
+  void collect_glyphs (hb_collect_glyphs_context_t *c) const
+  {
+    if (unlikely (!(this+coverage).collect_coverage (c->input))) return;
+    + hb_zip (this+coverage, alternateSet)
+    | hb_map (hb_second)
+    | hb_map (hb_add (this))
+    | hb_apply ([c] (const AlternateSet<Types> &_) { _.collect_glyphs (c); })
+    ;
+  }
+
+  const Coverage &get_coverage () const { return this+coverage; }
+
+  bool would_apply (hb_would_apply_context_t *c) const
+  { return c->len == 1 && (this+coverage).get_coverage (c->glyphs[0]) != NOT_COVERED; }
+
+  unsigned
+  get_glyph_alternates (hb_codepoint_t  gid,
+                        unsigned        start_offset,
+                        unsigned       *alternate_count  /* IN/OUT.  May be NULL. */,
+                        hb_codepoint_t *alternate_glyphs /* OUT.     May be NULL. */) const
+  { return (this+alternateSet[(this+coverage).get_coverage (gid)])
+           .get_alternates (start_offset, alternate_count, alternate_glyphs); }
+
+  bool apply (hb_ot_apply_context_t *c) const
+  {
+    TRACE_APPLY (this);
+
+    unsigned int index = (this+coverage).get_coverage (c->buffer->cur().codepoint);
+    if (likely (index == NOT_COVERED)) return_trace (false);
+
+    return_trace ((this+alternateSet[index]).apply (c));
+  }
+
+  bool serialize (hb_serialize_context_t *c,
+                  hb_sorted_array_t<const HBGlyphID16> glyphs,
+                  hb_array_t<const unsigned int> alternate_len_list,
+                  hb_array_t<const HBGlyphID16> alternate_glyphs_list)
+  {
+    TRACE_SERIALIZE (this);
+    if (unlikely (!c->extend_min (this))) return_trace (false);
+    if (unlikely (!alternateSet.serialize (c, glyphs.length))) return_trace (false);
+    for (unsigned int i = 0; i < glyphs.length; i++)
+    {
+      unsigned int alternate_len = alternate_len_list[i];
+      if (unlikely (!alternateSet[i]
+                        .serialize_serialize (c, alternate_glyphs_list.sub_array (0, alternate_len))))
+        return_trace (false);
+      alternate_glyphs_list += alternate_len;
+    }
+    return_trace (coverage.serialize_serialize (c, glyphs));
+  }
+
+  bool subset (hb_subset_context_t *c) const
+  {
+    TRACE_SUBSET (this);
+    const hb_set_t &glyphset = *c->plan->glyphset_gsub ();
+    const hb_map_t &glyph_map = *c->plan->glyph_map;
+
+    auto *out = c->serializer->start_embed (*this);
+    if (unlikely (!c->serializer->extend_min (out))) return_trace (false);
+    out->format = format;
+
+    hb_sorted_vector_t<hb_codepoint_t> new_coverage;
+    + hb_zip (this+coverage, alternateSet)
+    | hb_filter (glyphset, hb_first)
+    | hb_filter (subset_offset_array (c, out->alternateSet, this), hb_second)
+    | hb_map (hb_first)
+    | hb_map (glyph_map)
+    | hb_sink (new_coverage)
+    ;
+    out->coverage.serialize_serialize (c->serializer, new_coverage.iter ());
+    return_trace (bool (new_coverage));
+  }
+};
+
+}
+}
+}
+
+#endif  /* OT_LAYOUT_GSUB_ALTERNATESUBSTFORMAT1_HH */