dlib C++ Library - ref.h

// 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_