detail/core/adaptor.hpp

0001 ///////////////////////////////////////////////////////////////////////////////
0002 // adaptor.hpp
0003 //
0004 //  Copyright 2008 Eric Niebler. Distributed under the Boost
0005 //  Software License, Version 1.0. (See accompanying file
0006 //  LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
0007
0008 #ifndef BOOST_XPRESSIVE_DETAIL_CORE_ADAPTOR_HPP_EAN_10_04_2005
0009 #define BOOST_XPRESSIVE_DETAIL_CORE_ADAPTOR_HPP_EAN_10_04_2005
0010
0011 // MS compatible compilers support #pragma once
0012 #if defined(_MSC_VER)
0013 # pragma once
0014 #endif
0015
0016 #include <boost/ref.hpp>
0017 #include <boost/implicit_cast.hpp>
0018 #include <boost/intrusive_ptr.hpp>
0019 #include <boost/xpressive/detail/detail_fwd.hpp>
0020 #include <boost/xpressive/detail/dynamic/matchable.hpp>
0021
0022 namespace boost { namespace xpressive { namespace detail
0023 {
0024
0025 ///////////////////////////////////////////////////////////////////////////////
0026 // xpression_adaptor
0027 //
0028 //   wrap a static xpression in a matchable interface so it can be stored
0029 //   in and invoked from a basic_regex object.
0030 template<typename Xpr, typename Base>
0031 struct xpression_adaptor
0032   : Base // either matchable or matchable_ex
0033 {
0034     typedef typename Base::iterator_type iterator_type;
0035     typedef typename iterator_value<iterator_type>::type char_type;
0036
0037     Xpr xpr_;
0038
0039     xpression_adaptor(Xpr const &xpr)
0040     #if BOOST_WORKAROUND(__GNUC__, BOOST_TESTED_AT(4))
0041         // Ugh, gcc has an optimizer bug which elides this c'tor call
0042         // resulting in pure virtual function calls.
0043         __attribute__((__noinline__))
0044     #endif
0045       : xpr_(xpr)
0046     {
0047     }
0048
0049     virtual bool match(match_state<iterator_type> &state) const
0050     {
0051         typedef typename boost::unwrap_reference<Xpr const>::type xpr_type;
0052         return implicit_cast<xpr_type &>(this->xpr_).match(state);
0053     }
0054
0055     void link(xpression_linker<char_type> &linker) const
0056     {
0057         this->xpr_.link(linker);
0058     }
0059
0060     void peek(xpression_peeker<char_type> &peeker) const
0061     {
0062         this->xpr_.peek(peeker);
0063     }
0064
0065 private:
0066     xpression_adaptor &operator =(xpression_adaptor const &);
0067 };
0068
0069 ///////////////////////////////////////////////////////////////////////////////
0070 // make_adaptor
0071 //
0072 template<typename Base, typename Xpr>
0073 inline intrusive_ptr<Base const> make_adaptor(Xpr const &xpr)
0074 {
0075     return intrusive_ptr<Base const>(new xpression_adaptor<Xpr, Base>(xpr));
0076 }
0077
0078 }}} // namespace boost::xpressive::detail
0079
0080 #endif