Chris@16: //-----------------------------------------------------------------------------
Chris@16: // boost variant/get.hpp header file
Chris@16: // See http://www.boost.org for updates, documentation, and revision history.
Chris@16: //-----------------------------------------------------------------------------
Chris@16: //
Chris@101: // Copyright (c) 2003 Eric Friedman, Itay Maman
Chris@101: // Copyright (c) 2014 Antony Polukhin
Chris@16: //
Chris@16: // Distributed under the Boost Software License, Version 1.0. (See
Chris@16: // accompanying file LICENSE_1_0.txt or copy at
Chris@16: // http://www.boost.org/LICENSE_1_0.txt)
Chris@16: 
Chris@16: #ifndef BOOST_VARIANT_GET_HPP
Chris@16: #define BOOST_VARIANT_GET_HPP
Chris@16: 
Chris@16: #include <exception>
Chris@16: 
Chris@16: #include "boost/config.hpp"
Chris@16: #include "boost/detail/workaround.hpp"
Chris@101: #include "boost/static_assert.hpp"
Chris@16: #include "boost/throw_exception.hpp"
Chris@16: #include "boost/utility/addressof.hpp"
Chris@16: #include "boost/variant/variant_fwd.hpp"
Chris@101: #include "boost/variant/detail/element_index.hpp"
Chris@16: 
Chris@16: #include "boost/type_traits/add_reference.hpp"
Chris@16: #include "boost/type_traits/add_pointer.hpp"
Chris@16: 
Chris@16: namespace boost {
Chris@16: 
Chris@16: //////////////////////////////////////////////////////////////////////////
Chris@16: // class bad_get
Chris@16: //
Chris@16: // The exception thrown in the event of a failed get of a value.
Chris@16: //
Chris@101: class BOOST_SYMBOL_VISIBLE bad_get
Chris@16:     : public std::exception
Chris@16: {
Chris@16: public: // std::exception implementation
Chris@16: 
Chris@16:     virtual const char * what() const BOOST_NOEXCEPT_OR_NOTHROW
Chris@16:     {
Chris@16:         return "boost::bad_get: "
Chris@16:                "failed value get using boost::get";
Chris@16:     }
Chris@16: 
Chris@16: };
Chris@16: 
Chris@16: //////////////////////////////////////////////////////////////////////////
Chris@16: // function template get<T>
Chris@16: //
Chris@16: // Retrieves content of given variant object if content is of type T.
Chris@16: // Otherwise: pointer ver. returns 0; reference ver. throws bad_get.
Chris@16: //
Chris@16: 
Chris@16: namespace detail { namespace variant {
Chris@16: 
Chris@16: // (detail) class template get_visitor
Chris@16: //
Chris@16: // Generic static visitor that: if the value is of the specified type,
Chris@16: // returns a pointer to the value it visits; else a null pointer.
Chris@16: //
Chris@16: template <typename T>
Chris@16: struct get_visitor
Chris@16: {
Chris@16: private: // private typedefs
Chris@16: 
Chris@16:     typedef typename add_pointer<T>::type pointer;
Chris@16:     typedef typename add_reference<T>::type reference;
Chris@16: 
Chris@16: public: // visitor typedefs
Chris@16: 
Chris@16:     typedef pointer result_type;
Chris@16: 
Chris@16: public: // visitor interfaces
Chris@16: 
Chris@101:     pointer operator()(reference operand) const BOOST_NOEXCEPT
Chris@16:     {
Chris@16:         return boost::addressof(operand);
Chris@16:     }
Chris@16: 
Chris@16:     template <typename U>
Chris@101:     pointer operator()(const U&) const BOOST_NOEXCEPT
Chris@16:     {
Chris@16:         return static_cast<pointer>(0);
Chris@16:     }
Chris@16: };
Chris@16: 
Chris@16: }} // namespace detail::variant
Chris@16: 
Chris@101: #ifndef BOOST_VARIANT_AUX_GET_EXPLICIT_TEMPLATE_TYPE
Chris@101: #   if !BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x0551))
Chris@101: #       define BOOST_VARIANT_AUX_GET_EXPLICIT_TEMPLATE_TYPE(t)
Chris@101: #   else
Chris@101: #       define BOOST_VARIANT_AUX_GET_EXPLICIT_TEMPLATE_TYPE(t)  \
Chris@101:         , t* = 0
Chris@101: #   endif
Chris@16: #endif
Chris@16: 
Chris@101: /////////////////////////////////////////////////////////////////////////////////////////////////////////////
Chris@101: // relaxed_get<U>(variant) methods
Chris@101: //
Chris@16: template <typename U, BOOST_VARIANT_ENUM_PARAMS(typename T) >
Chris@16: inline
Chris@16:     typename add_pointer<U>::type
Chris@101: relaxed_get(
Chris@16:       boost::variant< BOOST_VARIANT_ENUM_PARAMS(T) >* operand
Chris@16:       BOOST_VARIANT_AUX_GET_EXPLICIT_TEMPLATE_TYPE(U)
Chris@101:     ) BOOST_NOEXCEPT
Chris@16: {
Chris@16:     typedef typename add_pointer<U>::type U_ptr;
Chris@16:     if (!operand) return static_cast<U_ptr>(0);
Chris@16: 
Chris@16:     detail::variant::get_visitor<U> v;
Chris@16:     return operand->apply_visitor(v);
Chris@16: }
Chris@16: 
Chris@16: template <typename U, BOOST_VARIANT_ENUM_PARAMS(typename T) >
Chris@16: inline
Chris@16:     typename add_pointer<const U>::type
Chris@101: relaxed_get(
Chris@16:       const boost::variant< BOOST_VARIANT_ENUM_PARAMS(T) >* operand
Chris@16:       BOOST_VARIANT_AUX_GET_EXPLICIT_TEMPLATE_TYPE(U)
Chris@101:     ) BOOST_NOEXCEPT
Chris@16: {
Chris@16:     typedef typename add_pointer<const U>::type U_ptr;
Chris@16:     if (!operand) return static_cast<U_ptr>(0);
Chris@16: 
Chris@16:     detail::variant::get_visitor<const U> v;
Chris@16:     return operand->apply_visitor(v);
Chris@16: }
Chris@16: 
Chris@16: template <typename U, BOOST_VARIANT_ENUM_PARAMS(typename T) >
Chris@16: inline
Chris@16:     typename add_reference<U>::type
Chris@101: relaxed_get(
Chris@101:       boost::variant< BOOST_VARIANT_ENUM_PARAMS(T) >& operand
Chris@101:       BOOST_VARIANT_AUX_GET_EXPLICIT_TEMPLATE_TYPE(U)
Chris@101:     )
Chris@101: {
Chris@101:     typedef typename add_pointer<U>::type U_ptr;
Chris@101:     U_ptr result = relaxed_get<U>(&operand);
Chris@101: 
Chris@101:     if (!result)
Chris@101:         boost::throw_exception(bad_get());
Chris@101:     return *result;
Chris@101: }
Chris@101: 
Chris@101: template <typename U, BOOST_VARIANT_ENUM_PARAMS(typename T) >
Chris@101: inline
Chris@101:     typename add_reference<const U>::type
Chris@101: relaxed_get(
Chris@101:       const boost::variant< BOOST_VARIANT_ENUM_PARAMS(T) >& operand
Chris@101:       BOOST_VARIANT_AUX_GET_EXPLICIT_TEMPLATE_TYPE(U)
Chris@101:     )
Chris@101: {
Chris@101:     typedef typename add_pointer<const U>::type U_ptr;
Chris@101:     U_ptr result = relaxed_get<const U>(&operand);
Chris@101: 
Chris@101:     if (!result)
Chris@101:         boost::throw_exception(bad_get());
Chris@101:     return *result;
Chris@101: }
Chris@101: 
Chris@101: 
Chris@101: 
Chris@101: /////////////////////////////////////////////////////////////////////////////////////////////////////////////
Chris@101: // strict_get<U>(variant) methods
Chris@101: //
Chris@101: template <typename U, BOOST_VARIANT_ENUM_PARAMS(typename T) >
Chris@101: inline
Chris@101:     typename add_pointer<U>::type
Chris@101: strict_get(
Chris@101:       boost::variant< BOOST_VARIANT_ENUM_PARAMS(T) >* operand
Chris@101:       BOOST_VARIANT_AUX_GET_EXPLICIT_TEMPLATE_TYPE(U)
Chris@101:     ) BOOST_NOEXCEPT
Chris@101: {
Chris@101:     BOOST_STATIC_ASSERT_MSG(
Chris@101:         (boost::detail::variant::holds_element<boost::variant< BOOST_VARIANT_ENUM_PARAMS(T) >, U >::value),
Chris@101:         "boost::variant does not contain specified type U, "
Chris@101:         "call to boost::get<U>(boost::variant<T...>*) will always return NULL"
Chris@101:     );
Chris@101: 
Chris@101:     return relaxed_get<U>(operand);
Chris@101: }
Chris@101: 
Chris@101: template <typename U, BOOST_VARIANT_ENUM_PARAMS(typename T) >
Chris@101: inline
Chris@101:     typename add_pointer<const U>::type
Chris@101: strict_get(
Chris@101:       const boost::variant< BOOST_VARIANT_ENUM_PARAMS(T) >* operand
Chris@101:       BOOST_VARIANT_AUX_GET_EXPLICIT_TEMPLATE_TYPE(U)
Chris@101:     ) BOOST_NOEXCEPT
Chris@101: {
Chris@101:     BOOST_STATIC_ASSERT_MSG(
Chris@101:         (boost::detail::variant::holds_element<boost::variant< BOOST_VARIANT_ENUM_PARAMS(T) >, const U >::value),
Chris@101:         "boost::variant does not contain specified type U, "
Chris@101:         "call to boost::get<U>(const boost::variant<T...>*) will always return NULL"
Chris@101:     );
Chris@101: 
Chris@101:     return relaxed_get<U>(operand);
Chris@101: }
Chris@101: 
Chris@101: template <typename U, BOOST_VARIANT_ENUM_PARAMS(typename T) >
Chris@101: inline
Chris@101:     typename add_reference<U>::type
Chris@101: strict_get(
Chris@101:       boost::variant< BOOST_VARIANT_ENUM_PARAMS(T) >& operand
Chris@101:       BOOST_VARIANT_AUX_GET_EXPLICIT_TEMPLATE_TYPE(U)
Chris@101:     )
Chris@101: {
Chris@101:     BOOST_STATIC_ASSERT_MSG(
Chris@101:         (boost::detail::variant::holds_element<boost::variant< BOOST_VARIANT_ENUM_PARAMS(T) >, U >::value),
Chris@101:         "boost::variant does not contain specified type U, "
Chris@101:         "call to boost::get<U>(boost::variant<T...>&) will always throw boost::bad_get exception"
Chris@101:     );
Chris@101: 
Chris@101:     return relaxed_get<U>(operand);
Chris@101: }
Chris@101: 
Chris@101: template <typename U, BOOST_VARIANT_ENUM_PARAMS(typename T) >
Chris@101: inline
Chris@101:     typename add_reference<const U>::type
Chris@101: strict_get(
Chris@101:       const boost::variant< BOOST_VARIANT_ENUM_PARAMS(T) >& operand
Chris@101:       BOOST_VARIANT_AUX_GET_EXPLICIT_TEMPLATE_TYPE(U)
Chris@101:     )
Chris@101: {
Chris@101:     BOOST_STATIC_ASSERT_MSG(
Chris@101:         (boost::detail::variant::holds_element<boost::variant< BOOST_VARIANT_ENUM_PARAMS(T) >, const U >::value),
Chris@101:         "boost::variant does not contain specified type U, "
Chris@101:         "call to boost::get<U>(const boost::variant<T...>&) will always throw boost::bad_get exception"
Chris@101:     );
Chris@101: 
Chris@101:     return relaxed_get<U>(operand);
Chris@101: }
Chris@101: 
Chris@101: /////////////////////////////////////////////////////////////////////////////////////////////////////////////
Chris@101: // get<U>(variant) methods
Chris@101: //
Chris@101: 
Chris@101: template <typename U, BOOST_VARIANT_ENUM_PARAMS(typename T) >
Chris@101: inline
Chris@101:     typename add_pointer<U>::type
Chris@101: get(
Chris@101:       boost::variant< BOOST_VARIANT_ENUM_PARAMS(T) >* operand
Chris@101:       BOOST_VARIANT_AUX_GET_EXPLICIT_TEMPLATE_TYPE(U)
Chris@101:     ) BOOST_NOEXCEPT
Chris@101: {
Chris@101: #ifdef BOOST_VARIANT_USE_RELAXED_GET_BY_DEFAULT
Chris@101:     return relaxed_get<U>(operand);
Chris@101: #else
Chris@101:     return strict_get<U>(operand);
Chris@101: #endif
Chris@101: 
Chris@101: }
Chris@101: 
Chris@101: template <typename U, BOOST_VARIANT_ENUM_PARAMS(typename T) >
Chris@101: inline
Chris@101:     typename add_pointer<const U>::type
Chris@101: get(
Chris@101:       const boost::variant< BOOST_VARIANT_ENUM_PARAMS(T) >* operand
Chris@101:       BOOST_VARIANT_AUX_GET_EXPLICIT_TEMPLATE_TYPE(U)
Chris@101:     ) BOOST_NOEXCEPT
Chris@101: {
Chris@101: #ifdef BOOST_VARIANT_USE_RELAXED_GET_BY_DEFAULT
Chris@101:     return relaxed_get<U>(operand);
Chris@101: #else
Chris@101:     return strict_get<U>(operand);
Chris@101: #endif
Chris@101: }
Chris@101: 
Chris@101: template <typename U, BOOST_VARIANT_ENUM_PARAMS(typename T) >
Chris@101: inline
Chris@101:     typename add_reference<U>::type
Chris@16: get(
Chris@16:       boost::variant< BOOST_VARIANT_ENUM_PARAMS(T) >& operand
Chris@16:       BOOST_VARIANT_AUX_GET_EXPLICIT_TEMPLATE_TYPE(U)
Chris@16:     )
Chris@16: {
Chris@101: #ifdef BOOST_VARIANT_USE_RELAXED_GET_BY_DEFAULT
Chris@101:     return relaxed_get<U>(operand);
Chris@101: #else
Chris@101:     return strict_get<U>(operand);
Chris@101: #endif
Chris@16: }
Chris@16: 
Chris@16: template <typename U, BOOST_VARIANT_ENUM_PARAMS(typename T) >
Chris@16: inline
Chris@16:     typename add_reference<const U>::type
Chris@16: get(
Chris@16:       const boost::variant< BOOST_VARIANT_ENUM_PARAMS(T) >& operand
Chris@16:       BOOST_VARIANT_AUX_GET_EXPLICIT_TEMPLATE_TYPE(U)
Chris@16:     )
Chris@16: {
Chris@101: #ifdef BOOST_VARIANT_USE_RELAXED_GET_BY_DEFAULT
Chris@101:     return relaxed_get<U>(operand);
Chris@101: #else
Chris@101:     return strict_get<U>(operand);
Chris@101: #endif
Chris@16: }
Chris@16: 
Chris@16: } // namespace boost
Chris@16: 
Chris@16: #endif // BOOST_VARIANT_GET_HPP