webservices: Add support for optional and nillable fields in the reader.

dlls/webservices/webservices_private.h

@@ -105,6 +105,13 @@ void free_channel( struct channel * ) DECLSPEC_HIDDEN;
 HRESULT open_channel( struct channel *, const WS_ENDPOINT_ADDRESS * ) DECLSPEC_HIDDEN;
 HRESULT close_channel( struct channel * ) DECLSPEC_HIDDEN;
 
+static inline BOOL is_nil_value( const char *value, ULONG size )
+{
+    ULONG i;
+    for (i = 0; i < size; i++) if (value[i]) return FALSE;
+    return TRUE;
+}
+
 static inline void *heap_alloc( SIZE_T size )
 {
     return HeapAlloc( GetProcessHeap(), 0, size );

dlls/webservices/writer.c

@@ -1564,13 +1564,6 @@ static HRESULT write_type_xml_string( struct writer *writer, WS_TYPE_MAPPING map
     return write_type_text( writer, mapping, &utf8.text );
 }
 
-static inline BOOL is_nil_value( const char *value, ULONG size )
-{
-    ULONG i;
-    for (i = 0; i < size; i++) if (value[i]) return FALSE;
-    return TRUE;
-}
-
 static HRESULT write_add_nil_attribute( struct writer *writer )
 {
     static const WS_XML_STRING prefix = {1, (BYTE *)"a"};