From 9fb7497add9d92af6f58cf0db870e406a3ff829a Mon Sep 17 00:00:00 2001
From: Pavel Kirienko <pavel.kirienko@gmail.com>
Date: Fri, 10 Jul 2015 14:36:52 +0300
Subject: [PATCH] dsdlc: union tag generation

---
 .../libuavcan_dsdl_compiler/__init__.py       |  3 +++
 .../data_type_template.tmpl                   | 23 +++++++++++++++----
 libuavcan/dsdl_compiler/pyuavcan              |  2 +-
 3 files changed, 23 insertions(+), 5 deletions(-)

diff --git a/libuavcan/dsdl_compiler/libuavcan_dsdl_compiler/__init__.py b/libuavcan/dsdl_compiler/libuavcan_dsdl_compiler/__init__.py
index 85abc2aee4..a7a18bab9f 100644
--- a/libuavcan/dsdl_compiler/libuavcan_dsdl_compiler/__init__.py
+++ b/libuavcan/dsdl_compiler/libuavcan_dsdl_compiler/__init__.py
@@ -193,12 +193,15 @@ def generate_one_type(template_expander, t):
         inject_cpp_types(t.fields)
         inject_cpp_types(t.constants)
         t.all_attributes = t.fields + t.constants
+        t.union = t.union and len(t.fields)
     else:
         inject_cpp_types(t.request_fields)
         inject_cpp_types(t.request_constants)
         inject_cpp_types(t.response_fields)
         inject_cpp_types(t.response_constants)
         t.all_attributes = t.request_fields + t.request_constants + t.response_fields + t.response_constants
+        t.request_union = t.request_union and len(t.request_fields)
+        t.response_union = t.response_union and len(t.response_fields)
 
     # Constant properties
     def inject_constant_info(constants):
diff --git a/libuavcan/dsdl_compiler/libuavcan_dsdl_compiler/data_type_template.tmpl b/libuavcan/dsdl_compiler/libuavcan_dsdl_compiler/data_type_template.tmpl
index 4a61f42e0d..c9963fbc98 100644
--- a/libuavcan/dsdl_compiler/libuavcan_dsdl_compiler/data_type_template.tmpl
+++ b/libuavcan/dsdl_compiler/libuavcan_dsdl_compiler/data_type_template.tmpl
@@ -43,7 +43,7 @@ template <int _tmpl>
 % endif
 struct UAVCAN_EXPORT ${t.cpp_type_name}
 {
-<!--(macro generate_primary_body)--> #! type_name, max_bitlen, fields, constants
+<!--(macro generate_primary_body)--> #! type_name, max_bitlen, fields, constants, union
     typedef const ${type_name}<_tmpl>& ParameterType;
     typedef ${type_name}<_tmpl>& ReferenceType;
 
@@ -80,10 +80,23 @@ struct UAVCAN_EXPORT ${t.cpp_type_name}
     typename ::uavcan::StorageType< typename FieldTypes::${a.name} >::Type ${a.name};
     % endfor
 
+    % if union:
+private:    // Union tag definition
+    typedef IntegerSpec< ::uavcan::IntegerBitLen< ${len(fields)} >::Result,
+                         ::uavcan::SignednessUnsigned, ::uavcan::CastModeTruncate > TagType;
+
+    typename ::uavcan::StorageType< TagType >::Type _tag_;      // The name is mangled to avoid clashing with fields
+
+public:
+    % endif
+
     ${type_name}()
     % for idx,a in enumerate(fields):
         ${':' if idx == 0 else ','} ${a.name}()
     % endfor
+    % if union:
+        , _tag_()
+    % endif
     {
         ::uavcan::StaticAssert<_tmpl == 0>::check();  // Usage check
 
@@ -118,21 +131,23 @@ struct UAVCAN_EXPORT ${t.cpp_type_name}
     struct Request_
     {
         ${indent(generate_primary_body(type_name='Request_', max_bitlen=t.get_max_bitlen_request(), \
-                                       fields=t.request_fields, constants=t.request_constants))}
+                                       fields=t.request_fields, constants=t.request_constants, \
+                                       union=t.request_union))}
     };
 
     template <int _tmpl>
     struct Response_
     {
         ${indent(generate_primary_body(type_name='Response_', max_bitlen=t.get_max_bitlen_response(), \
-                                       fields=t.response_fields, constants=t.response_constants))}
+                                       fields=t.response_fields, constants=t.response_constants, \
+                                       union=t.response_union))}
     };
 
     typedef Request_<0> Request;
     typedef Response_<0> Response;
 % else:
     ${generate_primary_body(type_name=t.cpp_type_name, max_bitlen=t.get_max_bitlen(), \
-                            fields=t.fields, constants=t.constants)}
+                            fields=t.fields, constants=t.constants, union=t.union)}
 % endif
 
     /*
diff --git a/libuavcan/dsdl_compiler/pyuavcan b/libuavcan/dsdl_compiler/pyuavcan
index 7dc69a4ad1..36e12969c0 160000
--- a/libuavcan/dsdl_compiler/pyuavcan
+++ b/libuavcan/dsdl_compiler/pyuavcan
@@ -1 +1 @@
-Subproject commit 7dc69a4ad1ae545334e39ac9f4a6c181be59670e
+Subproject commit 36e12969c0bc60956541e487d1a99779cd2f108b