stl_compatibility.h

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/*
* STL standards compatibility functions
* (C) 2017 Tomasz Frydrych
*
* Botan is released under the Simplified BSD License (see license.txt)
*/

#ifndef BOTAN_STL_COMPATIBILITY_H_
#define BOTAN_STL_COMPATIBILITY_H_

#include <memory>

#if __cplusplus < 201402L
#include <cstddef>
#include <type_traits>
#include <utility>
#endif

namespace Botan
{
/*
* std::make_unique functionality similar as we have in C++14.
* C++11 version based on proposal for C++14 implemenatation by Stephan T. Lavavej
* source: https://isocpp.org/files/papers/N3656.txt
*/
#if __cplusplus >= 201402L
template <typename T, typename ... Args>
constexpr auto make_unique(Args&&... args)
   {
   return std::make_unique<T>(std::forward<Args>(args)...);
   }

template<class T>
constexpr auto make_unique(std::size_t size)
   {
   return std::make_unique<T>(size);
   }

#else
namespace stlCompatibilityDetails
{
template<class T> struct _Unique_if
   {
   typedef std::unique_ptr<T> _Single_object;
   };

template<class T> struct _Unique_if<T[]>
   {
   typedef std::unique_ptr<T[]> _Unknown_bound;
   };

template<class T, size_t N> struct _Unique_if<T[N]>
   {
   typedef void _Known_bound;
   };
}  // namespace stlCompatibilityDetails

template<class T, class... Args>
typename stlCompatibilityDetails::_Unique_if<T>::_Single_object make_unique(Args&&... args)
   {
   return std::unique_ptr<T>(new T(std::forward<Args>(args)...));
   }

template<class T>
typename stlCompatibilityDetails::_Unique_if<T>::_Unknown_bound make_unique(size_t n)
   {
   typedef typename std::remove_extent<T>::type U;
   return std::unique_ptr<T>(new U[n]());
   }

template<class T, class... Args>
typename stlCompatibilityDetails::_Unique_if<T>::_Known_bound make_unique(Args&&...) = delete;

#endif

}  // namespace Botan
#endif