75 lines
1.8 KiB
C++
75 lines
1.8 KiB
C++
/*
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* Copyright Andrey Semashev 2007 - 2015.
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* Distributed under the Boost Software License, Version 1.0.
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* (See 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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/*!
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* \file attribute_cast.hpp
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* \author Andrey Semashev
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* \date 06.08.2010
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*
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* The header contains utilities for casting between attribute factories.
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*/
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#ifndef BOOST_LOG_ATTRIBUTES_ATTRIBUTE_CAST_HPP_INCLUDED_
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#define BOOST_LOG_ATTRIBUTES_ATTRIBUTE_CAST_HPP_INCLUDED_
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#include <boost/log/detail/config.hpp>
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#include <boost/log/attributes/attribute.hpp>
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#include <boost/log/detail/header.hpp>
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#ifdef BOOST_HAS_PRAGMA_ONCE
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#pragma once
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#endif
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namespace boost {
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BOOST_LOG_OPEN_NAMESPACE
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namespace attributes {
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/*!
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* The class holds a reference to the attribute factory implementation being casted
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*/
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class cast_source
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{
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private:
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attribute::impl* m_pImpl;
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public:
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/*!
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* Initializing constructor. Creates a source that refers to the specified factory implementation.
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*/
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explicit cast_source(attribute::impl* p) : m_pImpl(p)
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{
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}
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/*!
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* The function attempts to cast the aggregated pointer to the implementation to the specified type.
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*
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* \return The converted pointer or \c NULL, if the conversion fails.
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*/
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template< typename T >
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T* as() const { return dynamic_cast< T* >(m_pImpl); }
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};
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} // namespace attributes
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/*!
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* The function casts one attribute factory to another
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*/
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template< typename T >
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inline T attribute_cast(attribute const& attr)
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{
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return T(attributes::cast_source(attr.get_impl()));
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}
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BOOST_LOG_CLOSE_NAMESPACE // namespace log
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} // namespace boost
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#include <boost/log/detail/footer.hpp>
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#endif // BOOST_LOG_ATTRIBUTES_ATTRIBUTE_CAST_HPP_INCLUDED_
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