Add the correction for the encoder and decoder

Author: martinfantini

src/mfast/aggregate_ref.h

@@ -57,6 +57,7 @@ class aggregate_cref {
     this->instruction_ = other.instruction_;
     this->storage_array_ = other.storage_array_;
   }
+  bool content() const { return storage_array_->of_group.content_ != nullptr; }
 
   class iterator
       : public boost::iterator_facade<iterator, field_cref,

src/mfast/coder/encoder/fast_encoder.cpp

@@ -195,8 +195,12 @@ void fast_encoder_impl::visit(message_cref cref, bool force_reset) {
   aggregate_cref message(cref.field_storage(0), instruction);
 
   for (auto &&field : message)
+  {
     if (field.present() || field.instruction()->field_operator() == operator_none)
       apply_accessor(*this, field);
+    else if (!field.present() && field.instruction()->pmap_size())
+      current_pmap().set_next_bit(false);
+  }
 
   pmap.commit();
 }

src/mfast/ext_ref.h

@@ -183,6 +183,23 @@ class ext_cref<BaseCRef, sequence_element_tag, Properties>
   aggregate_cref base_;
 };
 
+template <typename BaseCRef, typename Properties>
+class ext_cref<BaseCRef, group_type_tag, Properties>
+    : public ext_ref_properties<group_type_tag, Properties> {
+public:
+  typedef BaseCRef cref_type;
+  typedef typename cref_type::type_category type_category;
+  typedef group_type_tag operator_category;
+
+  explicit ext_cref(const field_cref &base) : base_(base) {}
+  explicit ext_cref(const aggregate_cref &base) : base_(base) {}
+  cref_type get() const { return base_; }
+  bool present() const { return !this->optional() || base_.content(); }
+
+private:
+  cref_type base_;
+};
+
 template <typename Properties>
 class ext_cref<nested_message_cref, group_type_tag, Properties>
     : public ext_ref_properties<group_type_tag, Properties> {