85 lines
2.3 KiB
C++
85 lines
2.3 KiB
C++
// Copyright (C) 2010 Davis E. King (davis@dlib.net)
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// License: Boost Software License See LICENSE.txt for the full license.
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#ifndef DLIB_REFERENCE_WRAPpER_H_
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#define DLIB_REFERENCE_WRAPpER_H_
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namespace dlib
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{
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// ----------------------------------------------------------------------------------------
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template<
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typename T
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>
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class reference_wrapper
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{
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/*!
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WHAT THIS OBJECT REPRESENTS
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This is a simple object that just holds a reference to another object.
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It is useful because it can serve as a kind of "copyable reference".
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!*/
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public:
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typedef T type;
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explicit reference_wrapper(T& o) : obj(&o) {}
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operator T&() const { return *obj; }
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T& get() const { return *obj; }
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private:
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T* obj;
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};
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// ----------------------------------------------------------------------------------------
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template <typename T>
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reference_wrapper<T> ref(
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T& obj
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) { return reference_wrapper<T>(obj); }
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/*!
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ensures
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- returns a reference_wrapper that contains a reference to obj.
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!*/
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// ----------------------------------------------------------------------------------------
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template <typename T>
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reference_wrapper<T> ref(
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reference_wrapper<T> obj
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) { return obj; }
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/*!
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ensures
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- returns the given reference_wrapper object without modification
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!*/
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// ----------------------------------------------------------------------------------------
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template <typename T>
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reference_wrapper<const T> cref(
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const T& obj
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) { return reference_wrapper<const T>(obj); }
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/*!
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ensures
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- returns a reference_wrapper that contains a constant reference to obj.
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!*/
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// ----------------------------------------------------------------------------------------
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template <typename T>
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reference_wrapper<const T> cref(
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reference_wrapper<T> obj
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) { return cref(obj.get()); }
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/*!
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ensures
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- converts the given reference_wrapper into a reference_wrapper that contains a
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constant reference.
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!*/
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// ----------------------------------------------------------------------------------------
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}
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#endif // DLIB_REFERENCE_WRAPpER_H_
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