From 5e458e918d7606ffa89dc79ee357391799b501a9 Mon Sep 17 00:00:00 2001
From: Pavel Kirienko <pavel.kirienko@gmail.com>
Date: Mon, 18 May 2015 22:29:09 +0300
Subject: [PATCH] MakeString<> helper template

---
 libuavcan/include/uavcan/marshal/array.hpp          | 13 +++++++++++++
 .../dynamic_node_id_server/storage_backend.hpp      |  2 +-
 .../dynamic_node_id_server/file_event_tracer.hpp    |  3 +--
 .../dynamic_node_id_server/file_storage_backend.hpp |  3 +--
 4 files changed, 16 insertions(+), 5 deletions(-)

diff --git a/libuavcan/include/uavcan/marshal/array.hpp b/libuavcan/include/uavcan/marshal/array.hpp
index 73277f4c1b..c7263d106e 100644
--- a/libuavcan/include/uavcan/marshal/array.hpp
+++ b/libuavcan/include/uavcan/marshal/array.hpp
@@ -1087,6 +1087,19 @@ inline bool operator!=(const R& rhs, const Array<T, ArrayMode, MaxSize>& lhs)
     return lhs.operator!=(rhs);
 }
 
+/**
+ * Shortcut for string-like array type instantiation.
+ * The proper way of doing this is actually "template<> using ... = ...", but this feature is not available in
+ * older C++ revisions which the library has to support.
+ */
+template <unsigned MaxSize>
+class MakeString
+{
+    MakeString();       // This class is not instantiatable.
+public:
+    typedef Array<IntegerSpec<8, SignednessUnsigned, CastModeSaturate>, ArrayModeDynamic, MaxSize> Type;
+};
+
 /**
  * YAML streamer specification for any Array<>
  */
diff --git a/libuavcan/include/uavcan/protocol/dynamic_node_id_server/storage_backend.hpp b/libuavcan/include/uavcan/protocol/dynamic_node_id_server/storage_backend.hpp
index 9e970dd671..9e2395c92a 100644
--- a/libuavcan/include/uavcan/protocol/dynamic_node_id_server/storage_backend.hpp
+++ b/libuavcan/include/uavcan/protocol/dynamic_node_id_server/storage_backend.hpp
@@ -37,7 +37,7 @@ public:
      * This type is used to exchange data chunks with the backend.
      * It doesn't use any dynamic memory; please refer to the Array<> class for details.
      */
-    typedef Array<IntegerSpec<8, SignednessUnsigned, CastModeTruncate>, ArrayModeDynamic, MaxStringLength> String;
+    typedef MakeString<MaxStringLength>::Type String;
 
     /**
      * Read one value from the storage.
diff --git a/libuavcan_drivers/posix/include/uavcan_posix/dynamic_node_id_server/file_event_tracer.hpp b/libuavcan_drivers/posix/include/uavcan_posix/dynamic_node_id_server/file_event_tracer.hpp
index c8e97244dd..3398a54418 100644
--- a/libuavcan_drivers/posix/include/uavcan_posix/dynamic_node_id_server/file_event_tracer.hpp
+++ b/libuavcan_drivers/posix/include/uavcan_posix/dynamic_node_id_server/file_event_tracer.hpp
@@ -34,8 +34,7 @@ class FileEventTracer : public uavcan::dynamic_node_id_server::IEventTracer
     /**
      * This type is used for the path
      */
-    typedef uavcan::Array<uavcan::IntegerSpec<8, uavcan::SignednessUnsigned, uavcan::CastModeTruncate>,
-                          uavcan::ArrayModeDynamic, MaxPathLength> PathString;
+    typedef uavcan::MakeString<MaxPathLength>::Type PathString;
 
     PathString path_;
 
diff --git a/libuavcan_drivers/posix/include/uavcan_posix/dynamic_node_id_server/file_storage_backend.hpp b/libuavcan_drivers/posix/include/uavcan_posix/dynamic_node_id_server/file_storage_backend.hpp
index e4ce8c8e23..fdf173cc13 100644
--- a/libuavcan_drivers/posix/include/uavcan_posix/dynamic_node_id_server/file_storage_backend.hpp
+++ b/libuavcan_drivers/posix/include/uavcan_posix/dynamic_node_id_server/file_storage_backend.hpp
@@ -39,8 +39,7 @@ class FileStorageBackend : public uavcan::dynamic_node_id_server::IStorageBacken
     /**
      * This type is used for the path
      */
-    typedef uavcan::Array<uavcan::IntegerSpec<8, uavcan::SignednessUnsigned, uavcan::CastModeTruncate>,
-                          uavcan::ArrayModeDynamic, MaxPathLength> PathString;
+    typedef uavcan::MakeString<MaxPathLength>::Type PathString;
 
     PathString base_path;