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// This file is part of OpenCV project.
// It is subject to the license terms in the LICENSE file found in the top-level directory
// of this distribution and at http://opencv.org/license.html.
//
// Copyright (C) 2018 Intel Corporation
#ifndef OPENCV_GAPI_UTIL_ANY_HPP
#define OPENCV_GAPI_UTIL_ANY_HPP
#include <memory>
#include <type_traits>
#include <typeinfo>
#include <utility>
#include <opencv2/gapi/util/throw.hpp>
#if defined(_MSC_VER)
// disable MSVC warning on "multiple copy constructors specified"
# pragma warning(disable: 4521)
#endif
namespace cv
{
namespace internal
{
template <class T, class Source>
T down_cast(Source operand)
{
#if defined(__GXX_RTTI) || defined(_CPPRTTI)
return dynamic_cast<T>(operand);
#else
#warning used static cast instead of dynamic because RTTI is disabled
return static_cast<T>(operand);
#endif
}
}
namespace util
{
class bad_any_cast : public std::bad_cast
{
public:
virtual const char* what() const noexcept override
{
return "Bad any cast";
}
};
//modeled against C++17 std::any
class any
{
private:
struct holder;
using holder_ptr = std::unique_ptr<holder>;
struct holder
{
virtual holder_ptr clone() = 0;
virtual ~holder() = default;
};
template <typename value_t>
struct holder_impl : holder
{
value_t v;
template<typename arg_t>
holder_impl(arg_t&& a) : v(std::forward<arg_t>(a)) {}
holder_ptr clone() override { return holder_ptr(new holder_impl (v));}
};
holder_ptr hldr;
public:
template<class value_t>
any(value_t&& arg) : hldr(new holder_impl<typename std::decay<value_t>::type>( std::forward<value_t>(arg))) {}
any(any const& src) : hldr( src.hldr ? src.hldr->clone() : nullptr) {}
//simple hack in order not to write enable_if<not any> for the template constructor
any(any & src) : any (const_cast<any const&>(src)) {}
any() = default;
any(any&& ) = default;
any& operator=(any&&) = default;
any& operator=(any const& src)
{
any copy(src);
swap(*this, copy);
return *this;
}
template<class value_t>
friend value_t* any_cast(any* operand);
template<class value_t>
friend const value_t* any_cast(const any* operand);
template<class value_t>
friend value_t& unsafe_any_cast(any& operand);
template<class value_t>
friend const value_t& unsafe_any_cast(const any& operand);
friend void swap(any & lhs, any& rhs)
{
swap(lhs.hldr, rhs.hldr);
}
};
template<class value_t>
value_t* any_cast(any* operand)
{
auto casted = internal::down_cast<any::holder_impl<typename std::decay<value_t>::type> *>(operand->hldr.get());
if (casted){
return & (casted->v);
}
return nullptr;
}
template<class value_t>
const value_t* any_cast(const any* operand)
{
auto casted = internal::down_cast<any::holder_impl<typename std::decay<value_t>::type> *>(operand->hldr.get());
if (casted){
return & (casted->v);
}
return nullptr;
}
template<class value_t>
value_t& any_cast(any& operand)
{
auto ptr = any_cast<value_t>(&operand);
if (ptr)
{
return *ptr;
}
throw_error(bad_any_cast());
}
template<class value_t>
const value_t& any_cast(const any& operand)
{
auto ptr = any_cast<value_t>(&operand);
if (ptr)
{
return *ptr;
}
throw_error(bad_any_cast());
}
template<class value_t>
inline value_t& unsafe_any_cast(any& operand)
{
#ifdef DEBUG
return any_cast<value_t>(operand);
#else
return static_cast<any::holder_impl<typename std::decay<value_t>::type> *>(operand.hldr.get())->v;
#endif
}
template<class value_t>
inline const value_t& unsafe_any_cast(const any& operand)
{
#ifdef DEBUG
return any_cast<value_t>(operand);
#else
return static_cast<any::holder_impl<typename std::decay<value_t>::type> *>(operand.hldr.get())->v;
#endif
}
} // namespace util
} // namespace cv
#if defined(_MSC_VER)
// Enable "multiple copy constructors specified" back
# pragma warning(default: 4521)
#endif
#endif // OPENCV_GAPI_UTIL_ANY_HPP