58 lines
1.6 KiB
C++
Executable File
58 lines
1.6 KiB
C++
Executable File
/*=============================================================================
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Copyright (c) 2003 Joel de Guzman
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Distributed under the Boost Software License, Version 1.0. (See accompanying
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file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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=============================================================================*/
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#if !defined(BOOST_SPIRIT_SAFE_BOOL_HPP)
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#define BOOST_SPIRIT_SAFE_BOOL_HPP
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#include <boost/config.hpp>
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#include <boost/detail/workaround.hpp>
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namespace boost { namespace spirit
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{
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namespace detail
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{
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template <typename T>
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struct no_base {};
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template <typename T>
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struct safe_bool_impl
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{
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#if BOOST_WORKAROUND(__MWERKS__, BOOST_TESTED_AT(0x3003))
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void stub(T*) {}
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typedef void (safe_bool_impl::*type)(T*);
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#else
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typedef T* TP; // workaround to make parsing easier
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TP stub;
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typedef TP safe_bool_impl::*type;
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#endif
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};
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}
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template <typename Derived, typename Base = detail::no_base<Derived> >
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struct safe_bool : Base
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{
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private:
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typedef detail::safe_bool_impl<Derived> impl_type;
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typedef typename impl_type::type bool_type;
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public:
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operator bool_type() const
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{
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return static_cast<const Derived*>(this)->operator_bool() ?
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&impl_type::stub : 0;
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}
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operator bool_type()
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{
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return static_cast<Derived*>(this)->operator_bool() ?
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&impl_type::stub : 0;
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}
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};
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}}
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#endif
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