--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mupdf-source/thirdparty/harfbuzz/src/OT/Layout/GSUB/SingleSubst.hh	Mon Sep 15 11:43:07 2025 +0200
@@ -0,0 +1,103 @@
+#ifndef OT_LAYOUT_GSUB_SINGLESUBST_HH
+#define OT_LAYOUT_GSUB_SINGLESUBST_HH
+
+#include "Common.hh"
+#include "SingleSubstFormat1.hh"
+#include "SingleSubstFormat2.hh"
+
+namespace OT {
+namespace Layout {
+namespace GSUB_impl {
+
+struct SingleSubst
+{
+  protected:
+  union {
+  HBUINT16				format;         /* Format identifier */
+  SingleSubstFormat1_3<SmallTypes>	format1;
+  SingleSubstFormat2_4<SmallTypes>	format2;
+#ifndef HB_NO_BEYOND_64K
+  SingleSubstFormat1_3<MediumTypes>	format3;
+  SingleSubstFormat2_4<MediumTypes>	format4;
+#endif
+  } u;
+
+  public:
+
+  template <typename context_t, typename ...Ts>
+  typename context_t::return_t dispatch (context_t *c, Ts&&... ds) const
+  {
+    TRACE_DISPATCH (this, u.format);
+    if (unlikely (!c->may_dispatch (this, &u.format))) return_trace (c->no_dispatch_return_value ());
+    switch (u.format) {
+    case 1: return_trace (c->dispatch (u.format1, std::forward<Ts> (ds)...));
+    case 2: return_trace (c->dispatch (u.format2, std::forward<Ts> (ds)...));
+#ifndef HB_NO_BEYOND_64K
+    case 3: return_trace (c->dispatch (u.format3, std::forward<Ts> (ds)...));
+    case 4: return_trace (c->dispatch (u.format4, std::forward<Ts> (ds)...));
+#endif
+    default:return_trace (c->default_return_value ());
+    }
+  }
+
+  template<typename Iterator,
+           hb_requires (hb_is_sorted_source_of (Iterator,
+                                                const hb_codepoint_pair_t))>
+  bool serialize (hb_serialize_context_t *c,
+                  Iterator glyphs)
+  {
+    TRACE_SERIALIZE (this);
+    if (unlikely (!c->extend_min (u.format))) return_trace (false);
+    unsigned format = 2;
+    unsigned delta = 0;
+    if (glyphs)
+    {
+      format = 1;
+      hb_codepoint_t mask = 0xFFFFu;
+
+#ifndef HB_NO_BEYOND_64K
+       if (+ glyphs
+	   | hb_map_retains_sorting (hb_first)
+	   | hb_filter ([] (hb_codepoint_t gid) { return gid > 0xFFFFu; }))
+       {
+	 format += 2;
+	 mask = 0xFFFFFFu;
+       }
+#endif
+
+      auto get_delta = [=] (hb_codepoint_pair_t _)
+                       { return (unsigned) (_.second - _.first) & mask; };
+      delta = get_delta (*glyphs);
+      if (!hb_all (++(+glyphs), delta, get_delta)) format += 1;
+    }
+
+    u.format = format;
+    switch (u.format) {
+    case 1: return_trace (u.format1.serialize (c,
+                                               + glyphs
+                                               | hb_map_retains_sorting (hb_first),
+                                               delta));
+    case 2: return_trace (u.format2.serialize (c, glyphs));
+#ifndef HB_NO_BEYOND_64K
+    case 3: return_trace (u.format3.serialize (c,
+                                               + glyphs
+                                               | hb_map_retains_sorting (hb_first),
+                                               delta));
+    case 4: return_trace (u.format4.serialize (c, glyphs));
+#endif
+    default:return_trace (false);
+    }
+  }
+};
+
+template<typename Iterator>
+static void
+SingleSubst_serialize (hb_serialize_context_t *c,
+                       Iterator it)
+{ c->start_embed<SingleSubst> ()->serialize (c, it); }
+
+}
+}
+}
+
+#endif /* OT_LAYOUT_GSUB_SINGLESUBST_HH */