Add option to allow for anonymous unions

3 files changed, 35 insertions, 4 deletions

diff --git a/generator/nanopb_generator.py b/generator/nanopb_generator.py
index 2dad4ec1..a21257b5 100755
--- a/generator/nanopb_generator.py
+++ b/generator/nanopb_generator.py
@@ -463,7 +463,10 @@ class Field:
         '''
 
         if self.rules == 'ONEOF':
-            result = '    PB_ONEOF_FIELD(%s, ' % self.union_name
+            if self.anonymous:
+                result = '    PB_ANONYMOUS_ONEOF_FIELD(%s, ' % self.union_name
+            else:
+                result = '    PB_ONEOF_FIELD(%s, ' % self.union_name
         else:
             result = '    PB_FIELD('
 
@@ -497,7 +500,10 @@ class Field:
             if self.rules == 'REPEATED' and self.allocation == 'STATIC':
                 check.append('pb_membersize(%s, %s[0])' % (self.struct_name, self.name))
             elif self.rules == 'ONEOF':
-                check.append('pb_membersize(%s, %s.%s)' % (self.struct_name, self.union_name, self.name))
+                if self.anonymous:
+                    check.append('pb_membersize(%s, %s)' % (self.struct_name, self.name))
+                else:
+                    check.append('pb_membersize(%s, %s.%s)' % (self.struct_name, self.union_name, self.name))
             else:
                 check.append('pb_membersize(%s, %s)' % (self.struct_name, self.name))
 
@@ -653,6 +659,7 @@ class OneOf(Field):
         self.allocation = 'ONEOF'
         self.default = None
         self.rules = 'ONEOF'
+        self.anonymous = False
 
     def add_field(self, field):
         if field.allocation == 'CALLBACK':
@@ -661,6 +668,7 @@ class OneOf(Field):
 
         field.union_name = self.name
         field.rules = 'ONEOF'
+        field.anonymous = self.anonymous
         self.fields.append(field)
         self.fields.sort(key = lambda f: f.tag)
 
@@ -674,7 +682,10 @@ class OneOf(Field):
             result += '    union {\n'
             for f in self.fields:
                 result += '    ' + str(f).replace('\n', '\n    ') + '\n'
-            result += '    } ' + self.name + ';'
+            if self.anonymous:
+                result += '    };'
+            else:
+                result += '    } ' + self.name + ';'
         return result
 
     def types(self):
@@ -742,6 +753,8 @@ class Message:
                     pass # No union and skip fields also
                 else:
                     oneof = OneOf(self.name, f)
+                    if oneof_options.anonymous_oneof:
+                        oneof.anonymous = True
                     self.oneofs[i] = oneof
                     self.fields.append(oneof)
 
diff --git a/generator/proto/nanopb.proto b/generator/proto/nanopb.proto
index b8671bbd..9b2f0fbc 100644
--- a/generator/proto/nanopb.proto
+++ b/generator/proto/nanopb.proto
@@ -62,6 +62,9 @@ message NanoPBOptions {
 
   // integer type tag for a message
   optional uint32 msgid = 9;
+
+  // decode oneof as anonymous union
+  optional bool anonymous_oneof = 11 [default = false];
 }
 
 // Extensions to protoc 'Descriptor' type in order to define options
diff --git a/pb.h b/pb.h
index 98613a06..0286b855 100644
--- a/pb.h
+++ b/pb.h
@@ -518,10 +518,25 @@ struct pb_extension_s {
     pb_membersize(st, u.m[0]), 0, ptr}
 
 #define PB_ONEOF_FIELD(union_name, tag, type, rules, allocation, placement, message, field, prevfield, ptr) \
-        PB_ ## rules ## _ ## allocation(union_name, tag, message, field, \
+        PB_ ## ONEOF_ ## allocation(union_name, tag, message, field, \
         PB_DATAOFFSET_ ## placement(message, union_name.field, prevfield), \
         PB_LTYPE_MAP_ ## type, ptr)
 
+#define PB_ANONYMOUS_ONEOF_STATIC(u, tag, st, m, fd, ltype, ptr) \
+    {tag, PB_ATYPE_STATIC | PB_HTYPE_ONEOF | ltype, \
+    fd, pb_delta(st, which_ ## u, m), \
+    pb_membersize(st, m), 0, ptr}
+
+#define PB_ANONYMOUS_ONEOF_POINTER(u, tag, st, m, fd, ltype, ptr) \
+    {tag, PB_ATYPE_POINTER | PB_HTYPE_ONEOF | ltype, \
+    fd, pb_delta(st, which_ ## u, m), \
+    pb_membersize(st, m[0]), 0, ptr}
+
+#define PB_ANONYMOUS_ONEOF_FIELD(union_name, tag, type, rules, allocation, placement, message, field, prevfield, ptr) \
+        PB_ ## ANONYMOUS_ONEOF_ ## allocation(union_name, tag, message, field, \
+        PB_DATAOFFSET_ ## placement(message, field, prevfield), \
+        PB_LTYPE_MAP_ ## type, ptr)
+
 /* These macros are used for giving out error messages.
  * They are mostly a debugging aid; the main error information
  * is the true/false return value from functions.