diff --git a/lib/rb/ext/struct.h b/lib/rb/ext/struct.h
new file mode 100644
index 0000000..bf2350d
--- /dev/null
+++ b/lib/rb/ext/struct.h
@@ -0,0 +1,48 @@
+#include <stdbool.h>
+#include <ruby.h>
+
+typedef struct native_proto_method_table {
+  VALUE (*write_bool)(VALUE, VALUE);
+  VALUE (*write_byte)(VALUE, VALUE);
+  VALUE (*write_i16)(VALUE, VALUE);
+  VALUE (*write_i32)(VALUE, VALUE);
+  VALUE (*write_i64)(VALUE, VALUE);
+  VALUE (*write_double)(VALUE, VALUE);
+  VALUE (*write_string)(VALUE, VALUE);
+  VALUE (*write_list_begin)(VALUE, VALUE, VALUE);
+  VALUE (*write_list_end)(VALUE);
+  VALUE (*write_set_begin)(VALUE, VALUE, VALUE);
+  VALUE (*write_set_end)(VALUE);
+  VALUE (*write_map_begin)(VALUE, VALUE, VALUE, VALUE);
+  VALUE (*write_map_end)(VALUE);
+  VALUE (*write_struct_begin)(VALUE, VALUE);
+  VALUE (*write_struct_end)(VALUE);
+  VALUE (*write_field_begin)(VALUE, VALUE, VALUE, VALUE);
+  VALUE (*write_field_end)(VALUE);
+  VALUE (*write_field_stop)(VALUE);
+  VALUE (*write_message_begin)(VALUE, VALUE, VALUE, VALUE);
+  VALUE (*write_message_end)(VALUE);
+  
+  VALUE (*read_message_begin)(VALUE);
+  VALUE (*read_message_end)(VALUE);
+  VALUE (*read_field_begin)(VALUE);
+  VALUE (*read_field_end)(VALUE);
+  VALUE (*read_map_begin)(VALUE);
+  VALUE (*read_map_end)(VALUE);
+  VALUE (*read_list_begin)(VALUE);
+  VALUE (*read_list_end)(VALUE);
+  VALUE (*read_set_begin)(VALUE);
+  VALUE (*read_set_end)(VALUE);
+  VALUE (*read_byte)(VALUE);
+  VALUE (*read_bool)(VALUE);
+  VALUE (*read_i16)(VALUE);
+  VALUE (*read_i32)(VALUE);
+  VALUE (*read_i64)(VALUE);
+  VALUE (*read_double)(VALUE);
+  VALUE (*read_string)(VALUE);
+  VALUE (*read_struct_begin)(VALUE);
+  VALUE (*read_struct_end)(VALUE);
+  
+} native_proto_method_table;
+
+void Init_struct();
\ No newline at end of file