Implementing to_lower transformation.

mikhail_beris · mikhail_beris · commit 3375ab7d1893 · 2007-08-29T14:45:07.000Z
diff --git a/boost/network/message/transformers.hpp b/boost/network/message/transformers.hpp
@@ -13,6 +13,7 @@
  */
 #include <boost/network/message/transformers/selectors.hpp>
 #include <boost/network/message/transformers/to_upper.hpp>
+#include <boost/network/message/transformers/to_lower.hpp>
 
 #include <boost/type_traits.hpp>
 
diff --git a/boost/network/message/transformers/to_lower.hpp b/boost/network/message/transformers/to_lower.hpp
@@ -0,0 +1,82 @@
+
+//          Copyright Dean Michael Berris 2007.
+// Distributed under the Boost Software License, Version 1.0.
+//    (See accompanying file LICENSE_1_0.txt or copy at
+//          http://www.boost.org/LICENSE_1_0.txt)
+
+#ifndef __NETWORK_MESSAGE_TRANSFORMERS_TO_LOWER_HPP__
+#define __NETWORK_MESSAGE_TRANSFORMERS_TO_LOWER_HPP__
+
+#include <boost/algorithm/string.hpp>
+
+/** to_lower.hpp
+ *
+ * Implements the to_lower transformer. This applies
+ * the to_lower string algorithm to a string, which
+ * is selected by the appropriate selector.
+ *
+ * This defines a type, to be applied using template
+ * metaprogramming on the selected string target.
+ */
+namespace boost { namespace network {
+
+    namespace impl {
+
+        template <class Selector>
+            struct to_lower_transformer { };
+
+        template <>
+            struct to_lower_transformer<selectors::source_selector> {
+                template <class Tag>
+                    void operator() (basic_message<Tag> & message_) const {
+                        boost::to_lower(message_.source());
+                    };
+
+                protected:
+                    ~to_lower_transformer() { };
+            };
+
+        template <>
+            struct to_lower_transformer<selectors::destination_selector> {
+                template <class Tag>
+                    void operator() (basic_message<Tag> & message_) const {
+                        boost::to_lower(message_.destination());
+                    };
+
+                protected:
+                    ~to_lower_transformer() { };
+            };
+
+    }; // namespace impl
+
+	namespace detail {
+		struct to_lower_placeholder_helper;
+	};
+
+	detail::to_lower_placeholder_helper to_lower_(detail::to_lower_placeholder_helper);
+
+	namespace detail {
+
+		struct to_lower_placeholder_helper {
+			template <class Selector>
+				struct type : public impl::to_lower_transformer<Selector> { };
+		private:
+			to_lower_placeholder_helper() {};
+			to_lower_placeholder_helper(to_lower_placeholder_helper const &) {};
+			friend to_lower_placeholder_helper boost::network::to_lower_(to_lower_placeholder_helper);
+		};
+
+	};
+
+	typedef detail::to_lower_placeholder_helper (*to_lower_placeholder)(detail::to_lower_placeholder_helper);
+
+	inline detail::to_lower_placeholder_helper to_lower_(detail::to_lower_placeholder_helper) {
+		return detail::to_lower_placeholder_helper();
+	};
+
+}; // namespace network
+
+}; // namespace boost
+
+#endif // __NETWORK_MESSAGE_TRANSFORMERS_TO_LOWER_HPP__
+
diff --git a/libs/network/test/message_transform_test.cpp b/libs/network/test/message_transform_test.cpp
@@ -9,7 +9,7 @@
 #include <boost/network.hpp>
 #include <algorithm>
 
-BOOST_AUTO_TEST_CASE ( message_transform_tolower ) {
+BOOST_AUTO_TEST_CASE ( message_transform_toupper ) {
     using namespace boost::network;
 
     message msg;
@@ -18,3 +18,14 @@ BOOST_AUTO_TEST_CASE ( message_transform_tolower ) {
     msg << transform(to_upper_, source_);
     BOOST_CHECK_EQUAL ( source(msg), "ME" );
 };
+
+BOOST_AUTO_TEST_CASE ( message_transform_tolower ) {
+    using namespace boost::network;
+
+    message msg;
+    msg << source("ME");
+    BOOST_CHECK_EQUAL ( source(msg), "ME" );
+    msg << transform(to_lower_, source_);
+    BOOST_CHECK_EQUAL ( source(msg), "me" );
+};
+
