--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mupdf-source/thirdparty/harfbuzz/src/OT/Layout/GSUB/Sequence.hh	Mon Sep 15 11:43:07 2025 +0200
@@ -0,0 +1,165 @@
+#ifndef OT_LAYOUT_GSUB_SEQUENCE_HH
+#define OT_LAYOUT_GSUB_SEQUENCE_HH
+
+#include "Common.hh"
+
+namespace OT {
+namespace Layout {
+namespace GSUB_impl {
+
+template <typename Types>
+struct Sequence
+{
+  protected:
+  Array16Of<typename Types::HBGlyphID>
+                substitute;             /* String of GlyphIDs to substitute */
+  public:
+  DEFINE_SIZE_ARRAY (2, substitute);
+
+  bool sanitize (hb_sanitize_context_t *c) const
+  {
+    TRACE_SANITIZE (this);
+    return_trace (substitute.sanitize (c));
+  }
+
+  bool intersects (const hb_set_t *glyphs) const
+  { return hb_all (substitute, glyphs); }
+
+  void closure (hb_closure_context_t *c) const
+  { c->output->add_array (substitute.arrayZ, substitute.len); }
+
+  void collect_glyphs (hb_collect_glyphs_context_t *c) const
+  { c->output->add_array (substitute.arrayZ, substitute.len); }
+
+  bool apply (hb_ot_apply_context_t *c) const
+  {
+    TRACE_APPLY (this);
+    unsigned int count = substitute.len;
+
+    /* Special-case to make it in-place and not consider this
+     * as a "multiplied" substitution. */
+    if (unlikely (count == 1))
+    {
+      if (HB_BUFFER_MESSAGE_MORE && c->buffer->messaging ())
+      {
+	c->buffer->sync_so_far ();
+	c->buffer->message (c->font,
+			    "replacing glyph at %d (multiple substitution)",
+			    c->buffer->idx);
+      }
+
+      c->replace_glyph (substitute.arrayZ[0]);
+
+      if (HB_BUFFER_MESSAGE_MORE && c->buffer->messaging ())
+      {
+	c->buffer->message (c->font,
+			    "replaced glyph at %d (multiple subtitution)",
+			    c->buffer->idx - 1);
+      }
+
+      return_trace (true);
+    }
+    /* Spec disallows this, but Uniscribe allows it.
+     * https://github.com/harfbuzz/harfbuzz/issues/253 */
+    else if (unlikely (count == 0))
+    {
+      if (HB_BUFFER_MESSAGE_MORE && c->buffer->messaging ())
+      {
+	c->buffer->sync_so_far ();
+	c->buffer->message (c->font,
+			    "deleting glyph at %d (multiple substitution)",
+			    c->buffer->idx);
+      }
+
+      c->buffer->delete_glyph ();
+
+      if (HB_BUFFER_MESSAGE_MORE && c->buffer->messaging ())
+      {
+	c->buffer->sync_so_far ();
+	c->buffer->message (c->font,
+			    "deleted glyph at %d (multiple substitution)",
+			    c->buffer->idx);
+      }
+
+      return_trace (true);
+    }
+
+    if (HB_BUFFER_MESSAGE_MORE && c->buffer->messaging ())
+    {
+      c->buffer->sync_so_far ();
+      c->buffer->message (c->font,
+			  "multiplying glyph at %d",
+			  c->buffer->idx);
+    }
+
+    unsigned int klass = _hb_glyph_info_is_ligature (&c->buffer->cur()) ?
+                         HB_OT_LAYOUT_GLYPH_PROPS_BASE_GLYPH : 0;
+    unsigned lig_id = _hb_glyph_info_get_lig_id (&c->buffer->cur());
+
+    for (unsigned int i = 0; i < count; i++)
+    {
+      /* If is attached to a ligature, don't disturb that.
+       * https://github.com/harfbuzz/harfbuzz/issues/3069 */
+      if (!lig_id)
+        _hb_glyph_info_set_lig_props_for_component (&c->buffer->cur(), i);
+      c->output_glyph_for_component (substitute.arrayZ[i], klass);
+    }
+    c->buffer->skip_glyph ();
+
+    if (HB_BUFFER_MESSAGE_MORE && c->buffer->messaging ())
+    {
+      c->buffer->sync_so_far ();
+
+      char buf[HB_MAX_CONTEXT_LENGTH * 16] = {0};
+      char *p = buf;
+
+      for (unsigned i = c->buffer->idx - count; i < c->buffer->idx; i++)
+      {
+	if (buf < p)
+	  *p++ = ',';
+	snprintf (p, sizeof(buf) - (p - buf), "%u", i);
+	p += strlen(p);
+      }
+
+      c->buffer->message (c->font,
+			  "multiplied glyphs at %s",
+			  buf);
+    }
+
+    return_trace (true);
+  }
+
+  template <typename Iterator,
+            hb_requires (hb_is_source_of (Iterator, hb_codepoint_t))>
+  bool serialize (hb_serialize_context_t *c,
+                  Iterator subst)
+  {
+    TRACE_SERIALIZE (this);
+    return_trace (substitute.serialize (c, subst));
+  }
+
+  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;
+
+    if (!intersects (&glyphset)) return_trace (false);
+
+    auto it =
+    + hb_iter (substitute)
+    | hb_map (glyph_map)
+    ;
+
+    auto *out = c->serializer->start_embed (*this);
+    return_trace (out->serialize (c->serializer, it));
+  }
+};
+
+
+}
+}
+}
+
+
+#endif /* OT_LAYOUT_GSUB_SEQUENCE_HH */