You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
383 lines
11 KiB
383 lines
11 KiB
//----------------------------------------------------------------------------- |
|
// boost variant/get.hpp header file |
|
// See http://www.boost.org for updates, documentation, and revision history. |
|
//----------------------------------------------------------------------------- |
|
// |
|
// Copyright (c) 2003 Eric Friedman, Itay Maman |
|
// Copyright (c) 2014-2019 Antony Polukhin |
|
// |
|
// Distributed under the Boost Software License, Version 1.0. (See |
|
// accompanying file LICENSE_1_0.txt or copy at |
|
// http://www.boost.org/LICENSE_1_0.txt) |
|
|
|
#ifndef BOOST_VARIANT_GET_HPP |
|
#define BOOST_VARIANT_GET_HPP |
|
|
|
#include <exception> |
|
|
|
#include <boost/config.hpp> |
|
#include <boost/detail/workaround.hpp> |
|
#include <boost/static_assert.hpp> |
|
#include <boost/throw_exception.hpp> |
|
#include <boost/utility/addressof.hpp> |
|
#include <boost/variant/variant_fwd.hpp> |
|
#include <boost/variant/detail/element_index.hpp> |
|
#include <boost/variant/detail/move.hpp> |
|
|
|
#include <boost/type_traits/add_reference.hpp> |
|
#include <boost/type_traits/add_pointer.hpp> |
|
#include <boost/type_traits/is_lvalue_reference.hpp> |
|
|
|
namespace boost { |
|
|
|
#if defined(BOOST_CLANG) |
|
# pragma clang diagnostic push |
|
# pragma clang diagnostic ignored "-Wweak-vtables" |
|
#endif |
|
////////////////////////////////////////////////////////////////////////// |
|
// class bad_get |
|
// |
|
// The exception thrown in the event of a failed get of a value. |
|
// |
|
class BOOST_SYMBOL_VISIBLE bad_get |
|
: public std::exception |
|
{ |
|
public: // std::exception implementation |
|
|
|
virtual const char * what() const BOOST_NOEXCEPT_OR_NOTHROW |
|
{ |
|
return "boost::bad_get: " |
|
"failed value get using boost::get"; |
|
} |
|
|
|
}; |
|
#if defined(BOOST_CLANG) |
|
# pragma clang diagnostic pop |
|
#endif |
|
|
|
|
|
////////////////////////////////////////////////////////////////////////// |
|
// function template get<T> |
|
// |
|
// Retrieves content of given variant object if content is of type T. |
|
// Otherwise: pointer ver. returns 0; reference ver. throws bad_get. |
|
// |
|
|
|
namespace detail { namespace variant { |
|
|
|
// (detail) class template get_visitor |
|
// |
|
// Generic static visitor that: if the value is of the specified type, |
|
// returns a pointer to the value it visits; else a null pointer. |
|
// |
|
template <typename T> |
|
struct get_visitor |
|
{ |
|
private: // private typedefs |
|
|
|
typedef typename add_pointer<T>::type pointer; |
|
typedef typename add_reference<T>::type reference; |
|
|
|
public: // visitor typedefs |
|
|
|
typedef pointer result_type; |
|
|
|
public: // visitor interfaces |
|
|
|
pointer operator()(reference operand) const BOOST_NOEXCEPT |
|
{ |
|
return boost::addressof(operand); |
|
} |
|
|
|
template <typename U> |
|
pointer operator()(const U&) const BOOST_NOEXCEPT |
|
{ |
|
return static_cast<pointer>(0); |
|
} |
|
}; |
|
|
|
}} // namespace detail::variant |
|
|
|
#ifndef BOOST_VARIANT_AUX_GET_EXPLICIT_TEMPLATE_TYPE |
|
# if !BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x0551)) |
|
# define BOOST_VARIANT_AUX_GET_EXPLICIT_TEMPLATE_TYPE(t) |
|
# else |
|
# define BOOST_VARIANT_AUX_GET_EXPLICIT_TEMPLATE_TYPE(t) \ |
|
, t* = 0 |
|
# endif |
|
#endif |
|
|
|
///////////////////////////////////////////////////////////////////////////////////////////////////////////// |
|
// relaxed_get<U>(variant) methods |
|
// |
|
template <typename U, BOOST_VARIANT_ENUM_PARAMS(typename T) > |
|
inline |
|
typename add_pointer<U>::type |
|
relaxed_get( |
|
boost::variant< BOOST_VARIANT_ENUM_PARAMS(T) >* operand |
|
BOOST_VARIANT_AUX_GET_EXPLICIT_TEMPLATE_TYPE(U) |
|
) BOOST_NOEXCEPT |
|
{ |
|
typedef typename add_pointer<U>::type U_ptr; |
|
if (!operand) return static_cast<U_ptr>(0); |
|
|
|
detail::variant::get_visitor<U> v; |
|
return operand->apply_visitor(v); |
|
} |
|
|
|
template <typename U, BOOST_VARIANT_ENUM_PARAMS(typename T) > |
|
inline |
|
typename add_pointer<const U>::type |
|
relaxed_get( |
|
const boost::variant< BOOST_VARIANT_ENUM_PARAMS(T) >* operand |
|
BOOST_VARIANT_AUX_GET_EXPLICIT_TEMPLATE_TYPE(U) |
|
) BOOST_NOEXCEPT |
|
{ |
|
typedef typename add_pointer<const U>::type U_ptr; |
|
if (!operand) return static_cast<U_ptr>(0); |
|
|
|
detail::variant::get_visitor<const U> v; |
|
return operand->apply_visitor(v); |
|
} |
|
|
|
template <typename U, BOOST_VARIANT_ENUM_PARAMS(typename T) > |
|
inline |
|
typename add_reference<U>::type |
|
relaxed_get( |
|
boost::variant< BOOST_VARIANT_ENUM_PARAMS(T) >& operand |
|
BOOST_VARIANT_AUX_GET_EXPLICIT_TEMPLATE_TYPE(U) |
|
) |
|
{ |
|
typedef typename add_pointer<U>::type U_ptr; |
|
U_ptr result = relaxed_get<U>(boost::addressof(operand)); |
|
|
|
if (!result) |
|
boost::throw_exception(bad_get()); |
|
return *result; |
|
} |
|
|
|
template <typename U, BOOST_VARIANT_ENUM_PARAMS(typename T) > |
|
inline |
|
typename add_reference<const U>::type |
|
relaxed_get( |
|
const boost::variant< BOOST_VARIANT_ENUM_PARAMS(T) >& operand |
|
BOOST_VARIANT_AUX_GET_EXPLICIT_TEMPLATE_TYPE(U) |
|
) |
|
{ |
|
typedef typename add_pointer<const U>::type U_ptr; |
|
U_ptr result = relaxed_get<const U>(boost::addressof(operand)); |
|
|
|
if (!result) |
|
boost::throw_exception(bad_get()); |
|
return *result; |
|
} |
|
|
|
#ifndef BOOST_NO_CXX11_RVALUE_REFERENCES |
|
|
|
#if defined(BOOST_MSVC) && (_MSC_VER < 1900) // MSVC-2014 has fixed the incorrect diagnostics. |
|
# pragma warning(push) |
|
# pragma warning(disable: 4172) // returning address of local variable or temporary |
|
#endif |
|
|
|
template <typename U, BOOST_VARIANT_ENUM_PARAMS(typename T) > |
|
inline |
|
U&& |
|
relaxed_get( |
|
boost::variant< BOOST_VARIANT_ENUM_PARAMS(T) >&& operand |
|
BOOST_VARIANT_AUX_GET_EXPLICIT_TEMPLATE_TYPE(U) |
|
) |
|
{ |
|
typedef typename add_pointer<U>::type U_ptr; |
|
U_ptr result = relaxed_get<U>(boost::addressof(operand)); |
|
|
|
if (!result) |
|
boost::throw_exception(bad_get()); |
|
return static_cast<U&&>(*result); |
|
} |
|
|
|
#if defined(BOOST_MSVC) && (_MSC_VER < 1900) |
|
# pragma warning(pop) |
|
#endif |
|
|
|
#endif |
|
|
|
///////////////////////////////////////////////////////////////////////////////////////////////////////////// |
|
// strict_get<U>(variant) methods |
|
// |
|
template <typename U, BOOST_VARIANT_ENUM_PARAMS(typename T) > |
|
inline |
|
typename add_pointer<U>::type |
|
strict_get( |
|
boost::variant< BOOST_VARIANT_ENUM_PARAMS(T) >* operand |
|
BOOST_VARIANT_AUX_GET_EXPLICIT_TEMPLATE_TYPE(U) |
|
) BOOST_NOEXCEPT |
|
{ |
|
BOOST_STATIC_ASSERT_MSG( |
|
(boost::detail::variant::holds_element<boost::variant< BOOST_VARIANT_ENUM_PARAMS(T) >, U >::value), |
|
"boost::variant does not contain specified type U, " |
|
"call to boost::get<U>(boost::variant<T...>*) will always return NULL" |
|
); |
|
|
|
return relaxed_get<U>(operand); |
|
} |
|
|
|
template <typename U, BOOST_VARIANT_ENUM_PARAMS(typename T) > |
|
inline |
|
typename add_pointer<const U>::type |
|
strict_get( |
|
const boost::variant< BOOST_VARIANT_ENUM_PARAMS(T) >* operand |
|
BOOST_VARIANT_AUX_GET_EXPLICIT_TEMPLATE_TYPE(U) |
|
) BOOST_NOEXCEPT |
|
{ |
|
BOOST_STATIC_ASSERT_MSG( |
|
(boost::detail::variant::holds_element<boost::variant< BOOST_VARIANT_ENUM_PARAMS(T) >, const U >::value), |
|
"boost::variant does not contain specified type U, " |
|
"call to boost::get<U>(const boost::variant<T...>*) will always return NULL" |
|
); |
|
|
|
return relaxed_get<U>(operand); |
|
} |
|
|
|
template <typename U, BOOST_VARIANT_ENUM_PARAMS(typename T) > |
|
inline |
|
typename add_reference<U>::type |
|
strict_get( |
|
boost::variant< BOOST_VARIANT_ENUM_PARAMS(T) >& operand |
|
BOOST_VARIANT_AUX_GET_EXPLICIT_TEMPLATE_TYPE(U) |
|
) |
|
{ |
|
BOOST_STATIC_ASSERT_MSG( |
|
(boost::detail::variant::holds_element<boost::variant< BOOST_VARIANT_ENUM_PARAMS(T) >, U >::value), |
|
"boost::variant does not contain specified type U, " |
|
"call to boost::get<U>(boost::variant<T...>&) will always throw boost::bad_get exception" |
|
); |
|
|
|
return relaxed_get<U>(operand); |
|
} |
|
|
|
template <typename U, BOOST_VARIANT_ENUM_PARAMS(typename T) > |
|
inline |
|
typename add_reference<const U>::type |
|
strict_get( |
|
const boost::variant< BOOST_VARIANT_ENUM_PARAMS(T) >& operand |
|
BOOST_VARIANT_AUX_GET_EXPLICIT_TEMPLATE_TYPE(U) |
|
) |
|
{ |
|
BOOST_STATIC_ASSERT_MSG( |
|
(boost::detail::variant::holds_element<boost::variant< BOOST_VARIANT_ENUM_PARAMS(T) >, const U >::value), |
|
"boost::variant does not contain specified type U, " |
|
"call to boost::get<U>(const boost::variant<T...>&) will always throw boost::bad_get exception" |
|
); |
|
|
|
return relaxed_get<U>(operand); |
|
} |
|
|
|
#ifndef BOOST_NO_CXX11_RVALUE_REFERENCES |
|
template <typename U, BOOST_VARIANT_ENUM_PARAMS(typename T) > |
|
inline |
|
U&& |
|
strict_get( |
|
boost::variant< BOOST_VARIANT_ENUM_PARAMS(T) >&& operand |
|
BOOST_VARIANT_AUX_GET_EXPLICIT_TEMPLATE_TYPE(U) |
|
) |
|
{ |
|
BOOST_STATIC_ASSERT_MSG( |
|
(!boost::is_lvalue_reference<U>::value), |
|
"remove ampersand '&' from template type U in boost::get<U>(boost::variant<T...>&&) " |
|
); |
|
|
|
BOOST_STATIC_ASSERT_MSG( |
|
(boost::detail::variant::holds_element<boost::variant< BOOST_VARIANT_ENUM_PARAMS(T) >, U >::value), |
|
"boost::variant does not contain specified type U, " |
|
"call to boost::get<U>(const boost::variant<T...>&) will always throw boost::bad_get exception" |
|
); |
|
|
|
return relaxed_get<U>(detail::variant::move(operand)); |
|
} |
|
#endif |
|
|
|
///////////////////////////////////////////////////////////////////////////////////////////////////////////// |
|
// get<U>(variant) methods |
|
// |
|
|
|
template <typename U, BOOST_VARIANT_ENUM_PARAMS(typename T) > |
|
inline |
|
typename add_pointer<U>::type |
|
get( |
|
boost::variant< BOOST_VARIANT_ENUM_PARAMS(T) >* operand |
|
BOOST_VARIANT_AUX_GET_EXPLICIT_TEMPLATE_TYPE(U) |
|
) BOOST_NOEXCEPT |
|
{ |
|
#ifdef BOOST_VARIANT_USE_RELAXED_GET_BY_DEFAULT |
|
return relaxed_get<U>(operand); |
|
#else |
|
return strict_get<U>(operand); |
|
#endif |
|
|
|
} |
|
|
|
template <typename U, BOOST_VARIANT_ENUM_PARAMS(typename T) > |
|
inline |
|
typename add_pointer<const U>::type |
|
get( |
|
const boost::variant< BOOST_VARIANT_ENUM_PARAMS(T) >* operand |
|
BOOST_VARIANT_AUX_GET_EXPLICIT_TEMPLATE_TYPE(U) |
|
) BOOST_NOEXCEPT |
|
{ |
|
#ifdef BOOST_VARIANT_USE_RELAXED_GET_BY_DEFAULT |
|
return relaxed_get<U>(operand); |
|
#else |
|
return strict_get<U>(operand); |
|
#endif |
|
} |
|
|
|
template <typename U, BOOST_VARIANT_ENUM_PARAMS(typename T) > |
|
inline |
|
typename add_reference<U>::type |
|
get( |
|
boost::variant< BOOST_VARIANT_ENUM_PARAMS(T) >& operand |
|
BOOST_VARIANT_AUX_GET_EXPLICIT_TEMPLATE_TYPE(U) |
|
) |
|
{ |
|
#ifdef BOOST_VARIANT_USE_RELAXED_GET_BY_DEFAULT |
|
return relaxed_get<U>(operand); |
|
#else |
|
return strict_get<U>(operand); |
|
#endif |
|
} |
|
|
|
template <typename U, BOOST_VARIANT_ENUM_PARAMS(typename T) > |
|
inline |
|
typename add_reference<const U>::type |
|
get( |
|
const boost::variant< BOOST_VARIANT_ENUM_PARAMS(T) >& operand |
|
BOOST_VARIANT_AUX_GET_EXPLICIT_TEMPLATE_TYPE(U) |
|
) |
|
{ |
|
#ifdef BOOST_VARIANT_USE_RELAXED_GET_BY_DEFAULT |
|
return relaxed_get<U>(operand); |
|
#else |
|
return strict_get<U>(operand); |
|
#endif |
|
} |
|
|
|
#ifndef BOOST_NO_CXX11_RVALUE_REFERENCES |
|
template <typename U, BOOST_VARIANT_ENUM_PARAMS(typename T) > |
|
inline |
|
U&& |
|
get( |
|
boost::variant< BOOST_VARIANT_ENUM_PARAMS(T) >&& operand |
|
BOOST_VARIANT_AUX_GET_EXPLICIT_TEMPLATE_TYPE(U) |
|
) |
|
{ |
|
#ifdef BOOST_VARIANT_USE_RELAXED_GET_BY_DEFAULT |
|
return relaxed_get<U>(detail::variant::move(operand)); |
|
#else |
|
return strict_get<U>(detail::variant::move(operand)); |
|
#endif |
|
} |
|
#endif |
|
|
|
} // namespace boost |
|
|
|
#endif // BOOST_VARIANT_GET_HPP
|
|
|