227 lines
5.7 KiB
C++
227 lines
5.7 KiB
C++
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// - casts.hpp -- BLambda Library -------------
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//
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// Copyright (C) 2000 Gary Powell (powellg@amazon.com)
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// Copyright (C) 1999, 2000 Jaakko Jarvi (jaakko.jarvi@cs.utu.fi)
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//
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// Distributed under the Boost Software License, Version 1.0. (See
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// accompanying file LICENSE_1_0.txt or copy at
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// http://www.boost.org/LICENSE_1_0.txt)
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//
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// For more information, see http://www.boost.org
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// -----------------------------------------------
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#if !defined(BOOST_LAMBDA_CASTS_HPP)
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#define BOOST_LAMBDA_CASTS_HPP
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#include "boost/lambda/detail/suppress_unused.hpp"
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#include "boost/lambda/core.hpp"
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#include <typeinfo>
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namespace boost {
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namespace lambda {
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template<class Act, class Args>
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struct return_type_N;
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template<class T> class cast_action;
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template<class T> class static_cast_action;
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template<class T> class dynamic_cast_action;
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template<class T> class const_cast_action;
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template<class T> class reinterpret_cast_action;
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class typeid_action;
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class sizeof_action;
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// Cast actions
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template<class T> class cast_action<static_cast_action<T> >
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{
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public:
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template<class RET, class Arg1>
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static RET apply(Arg1 &a1) {
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return static_cast<RET>(a1);
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}
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};
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template<class T> class cast_action<dynamic_cast_action<T> > {
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public:
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template<class RET, class Arg1>
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static RET apply(Arg1 &a1) {
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return dynamic_cast<RET>(a1);
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}
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};
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template<class T> class cast_action<const_cast_action<T> > {
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public:
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template<class RET, class Arg1>
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static RET apply(Arg1 &a1) {
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return const_cast<RET>(a1);
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}
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};
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template<class T> class cast_action<reinterpret_cast_action<T> > {
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public:
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template<class RET, class Arg1>
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static RET apply(Arg1 &a1) {
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return reinterpret_cast<RET>(a1);
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}
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};
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// typeid action
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class typeid_action {
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public:
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template<class RET, class Arg1>
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static RET apply(Arg1 &a1) {
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detail::suppress_unused_variable_warnings(a1);
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return typeid(a1);
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}
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};
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// sizeof action
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class sizeof_action
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{
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public:
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template<class RET, class Arg1>
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static RET apply(Arg1 &a1) {
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return sizeof(a1);
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}
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};
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// return types of casting lambda_functors (all "T" type.)
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template<template <class> class cast_type, class T, class A>
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struct return_type_N<cast_action< cast_type<T> >, A> {
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typedef T type;
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};
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// return type of typeid_action
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template<class A>
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struct return_type_N<typeid_action, A> {
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typedef std::type_info const & type;
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};
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// return type of sizeof_action
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template<class A>
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struct return_type_N<sizeof_action, A> {
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typedef std::size_t type;
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};
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// the four cast & typeid overloads.
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// casts can take ordinary variables (not just lambda functors)
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// static_cast
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template <class T, class Arg1>
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inline const lambda_functor<
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lambda_functor_base<
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action<1, cast_action<static_cast_action<T> > >,
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tuple<typename const_copy_argument <const Arg1>::type>
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>
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>
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ll_static_cast(const Arg1& a1) {
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return
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lambda_functor_base<
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action<1, cast_action<static_cast_action<T> > >,
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tuple<typename const_copy_argument <const Arg1>::type>
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>
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( tuple<typename const_copy_argument <const Arg1>::type>(a1));
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}
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// dynamic_cast
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template <class T, class Arg1>
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inline const lambda_functor<
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lambda_functor_base<
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action<1, cast_action<dynamic_cast_action<T> > >,
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tuple<typename const_copy_argument <const Arg1>::type>
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>
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>
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ll_dynamic_cast(const Arg1& a1) {
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return
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lambda_functor_base<
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action<1, cast_action<dynamic_cast_action<T> > >,
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tuple<typename const_copy_argument <const Arg1>::type>
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>
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( tuple<typename const_copy_argument <const Arg1>::type>(a1));
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}
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// const_cast
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template <class T, class Arg1>
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inline const lambda_functor<
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lambda_functor_base<
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action<1, cast_action<const_cast_action<T> > >,
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tuple<typename const_copy_argument <const Arg1>::type>
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>
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>
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ll_const_cast(const Arg1& a1) {
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return
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lambda_functor_base<
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action<1, cast_action<const_cast_action<T> > >,
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tuple<typename const_copy_argument <const Arg1>::type>
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>
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( tuple<typename const_copy_argument <const Arg1>::type>(a1));
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}
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// reinterpret_cast
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template <class T, class Arg1>
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inline const lambda_functor<
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lambda_functor_base<
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action<1, cast_action<reinterpret_cast_action<T> > >,
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tuple<typename const_copy_argument <const Arg1>::type>
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>
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>
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ll_reinterpret_cast(const Arg1& a1) {
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return
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lambda_functor_base<
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action<1, cast_action<reinterpret_cast_action<T> > >,
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tuple<typename const_copy_argument <const Arg1>::type>
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>
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( tuple<typename const_copy_argument <const Arg1>::type>(a1));
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}
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// typeid
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// can be applied to a normal variable as well (can refer to a polymorphic
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// class object)
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template <class Arg1>
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inline const lambda_functor<
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lambda_functor_base<
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action<1, typeid_action>,
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tuple<typename const_copy_argument <const Arg1>::type>
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>
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>
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ll_typeid(const Arg1& a1) {
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return
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lambda_functor_base<
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action<1, typeid_action>,
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tuple<typename const_copy_argument <const Arg1>::type>
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>
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( tuple<typename const_copy_argument <const Arg1>::type>(a1));
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}
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// sizeof(expression)
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// Always takes a lambda expression (if not, built in sizeof will do)
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template <class Arg1>
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inline const lambda_functor<
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lambda_functor_base<
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action<1, sizeof_action>,
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tuple<lambda_functor<Arg1> >
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>
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>
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ll_sizeof(const lambda_functor<Arg1>& a1) {
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return
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lambda_functor_base<
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action<1, sizeof_action>,
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tuple<lambda_functor<Arg1> >
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>
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( tuple<lambda_functor<Arg1> >(a1));
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}
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} // namespace lambda
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} // namespace boost
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#endif
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