[arrays] Start moving Supplier<> to hb_array_t<>

src/hb-machinery.hh

@@ -642,45 +642,36 @@ struct hb_serialize_context_t
  */
 
 template <typename Type>
-struct Supplier
+struct Supplier : hb_array_t<const Type>
 {
   Supplier (const Type *array, unsigned int len_)
   {
-    head = array;
-    len = len_;
+    this->arrayZ = array;
+    this->len = len_;
   }
   Supplier (hb_array_t<const Type> v)
   {
-    head = v.arrayZ;
-    len = v.len;
+    this->arrayZ = v.arrayZ;
+    this->len = v.len;
   }
   Supplier (const hb_vector_t<Type> &v)
   {
-    head = (const Type *) v;
-    len = v.len;
-  }
-
-  const Type operator [] (unsigned int i) const
-  {
-    if (unlikely (i >= len)) return Type ();
-    return head[i];
+    this->arrayZ = (const Type *) v;
+    this->len = v.len;
   }
 
   Supplier<Type> & operator += (unsigned int count)
   {
-    if (unlikely (count > len))
-      count = len;
-    len -= count;
-    head += count;
+    if (unlikely (count > this->len))
+      count = this->len;
+    this->len -= count;
+    this->arrayZ += count;
     return *this;
   }
 
   private:
   Supplier (const Supplier<Type> &); /* Disallow copy */
   Supplier<Type>& operator= (const Supplier<Type> &); /* Disallow copy */
-
-  unsigned int len;
-  const Type *head;
 };