diff --git a/src/hb-dsalgs.hh b/src/hb-dsalgs.hh
index 8cbe6584b..8d59c6cf3 100644
--- a/src/hb-dsalgs.hh
+++ b/src/hb-dsalgs.hh
@@ -502,6 +502,9 @@ struct hb_bytes_t
 {
   inline hb_bytes_t (void) : bytes (nullptr), len (0) {}
   inline hb_bytes_t (const char *bytes_, unsigned int len_) : bytes (bytes_), len (len_) {}
+  inline hb_bytes_t (const void *bytes_, unsigned int len_) : bytes ((const char *) bytes_), len (len_) {}
+
+  inline void free (void) { ::free ((void *) bytes); bytes = nullptr; len = 0; }
 
   inline int cmp (const hb_bytes_t &a) const
   {
diff --git a/src/hb-machinery-private.hh b/src/hb-machinery-private.hh
index 99ef485a3..05add1f4d 100644
--- a/src/hb-machinery-private.hh
+++ b/src/hb-machinery-private.hh
@@ -402,7 +402,7 @@ struct hb_serialize_context_t
   }
 
   template <typename Type>
-  inline Type *copy (void)
+  inline Type *copy (void) const
   {
     assert (!this->ran_out_of_room);
     unsigned int len = this->head - this->start;
@@ -411,6 +411,25 @@ struct hb_serialize_context_t
       memcpy (p, this->start, len);
     return reinterpret_cast<Type *> (p);
   }
+  inline hb_bytes_t copy_bytes (void) const
+  {
+    assert (!this->ran_out_of_room);
+    unsigned int len = this->head - this->start;
+    void *p = malloc (len);
+    if (p)
+      memcpy (p, this->start, len);
+    else
+      return hb_bytes_t ();
+    return hb_bytes_t (p, len);
+  }
+  inline hb_blob_t *copy_blob (void) const
+  {
+    assert (!this->ran_out_of_room);
+    return hb_blob_create (this->start,
+			   this->head - this->start,
+			   HB_MEMORY_MODE_DUPLICATE,
+			   nullptr, nullptr);
+  }
 
   template <typename Type>
   inline Type *allocate_size (unsigned int size)