65 lines
1.7 KiB
Plaintext
65 lines
1.7 KiB
Plaintext
/*=============================================================================
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Copyright (c) 2003 Joel de Guzman
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http://spirit.sourceforge.net/
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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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#include <boost/spirit/home/classic/namespace.hpp>
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namespace boost { namespace spirit {
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BOOST_SPIRIT_CLASSIC_NAMESPACE_BEGIN
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namespace impl
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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 DerivedT, typename BaseT = impl::no_base<DerivedT> >
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struct safe_bool : BaseT
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{
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private:
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typedef impl::safe_bool_impl<DerivedT> impl_t;
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typedef typename impl_t::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 DerivedT*>(this)->operator_bool() ?
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&impl_t::stub : 0;
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}
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operator bool_type()
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{
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return static_cast<DerivedT*>(this)->operator_bool() ?
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&impl_t::stub : 0;
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}
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};
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BOOST_SPIRIT_CLASSIC_NAMESPACE_END
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}}
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#endif
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