1 files changed, 84 insertions, 0 deletions
diff --git a/ml/dlib/dlib/ref.h b/ml/dlib/dlib/ref.h
new file mode 100644
index 000000000..53a37fbf8
--- /dev/null
+++ b/ml/dlib/dlib/ref.h
@@ -0,0 +1,84 @@
+// Copyright (C) 2010  Davis E. King (davis@dlib.net)
+// License: Boost Software License   See LICENSE.txt for the full license.
+#ifndef DLIB_REFERENCE_WRAPpER_H_
+#define DLIB_REFERENCE_WRAPpER_H_
+
+namespace dlib
+{
+
+// ----------------------------------------------------------------------------------------
+
+    template<
+        typename T
+        > 
+    class reference_wrapper 
+    {
+        /*!
+            WHAT THIS OBJECT REPRESENTS
+                This is a simple object that just holds a reference to another object. 
+                It is useful because it can serve as a kind of "copyable reference".  
+        !*/
+
+    public:
+        typedef T type;
+
+        explicit reference_wrapper(T& o) : obj(&o) {}
+
+        operator T&()    const { return  *obj; }
+        T& get()         const { return  *obj; }
+
+    private:
+        T* obj;
+    };
+
+// ----------------------------------------------------------------------------------------
+
+    template <typename T>
+    reference_wrapper<T> ref(
+        T& obj
+    ) { return reference_wrapper<T>(obj); }
+    /*!
+        ensures
+            - returns a reference_wrapper that contains a reference to obj.
+    !*/
+
+// ----------------------------------------------------------------------------------------
+
+    template <typename T>
+    reference_wrapper<T> ref(
+        reference_wrapper<T> obj
+    ) { return obj; }
+    /*!
+        ensures
+            - returns the given reference_wrapper object without modification
+    !*/
+
+// ----------------------------------------------------------------------------------------
+
+    template <typename T>
+    reference_wrapper<const T> cref(
+        const T& obj
+    ) { return reference_wrapper<const T>(obj); }
+    /*!
+        ensures
+            - returns a reference_wrapper that contains a constant reference to obj.
+    !*/
+
+// ----------------------------------------------------------------------------------------
+
+    template <typename T>
+    reference_wrapper<const T> cref(
+        reference_wrapper<T> obj
+    ) { return cref(obj.get()); }
+    /*!
+        ensures
+            - converts the given reference_wrapper into a reference_wrapper that contains a
+              constant reference.
+    !*/
+
+// ----------------------------------------------------------------------------------------
+
+}
+
+#endif // DLIB_REFERENCE_WRAPpER_H_
+