core/matcher/logical_newline_matcher.hpp

0001 ///////////////////////////////////////////////////////////////////////////////
0002 // logical_newline_matcher.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_MATCHER_LOGICAL_NEWLINE_MATCHER_HPP_EAN_10_04_2005
0009 #define BOOST_XPRESSIVE_DETAIL_CORE_MATCHER_LOGICAL_NEWLINE_MATCHER_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/xpressive/detail/detail_fwd.hpp>
0017 #include <boost/xpressive/detail/core/quant_style.hpp>
0018 #include <boost/xpressive/detail/core/state.hpp>
0019
0020 namespace boost { namespace xpressive { namespace detail
0021 {
0022
0023     //////////////////////////////////////////////////////////////////////////
0024     // logical_newline_matcher
0025     //
0026     template<typename Traits>
0027     struct logical_newline_matcher
0028       : quant_style_variable_width
0029     {
0030         typedef typename Traits::char_type char_type;
0031         typedef typename Traits::char_class_type char_class_type;
0032
0033         logical_newline_matcher(Traits const &tr)
0034           : newline_(lookup_classname(tr, "newline"))
0035           , nl_(tr.widen('\n'))
0036           , cr_(tr.widen('\r'))
0037         {
0038         }
0039
0040         template<typename BidiIter, typename Next>
0041         bool match(match_state<BidiIter> &state, Next const &next) const
0042         {
0043             if(state.eos())
0044             {
0045                 return false;
0046             }
0047
0048             char_type ch = *state.cur_;
0049             if(traits_cast<Traits>(state).isctype(ch, this->newline_))
0050             {
0051                 ++state.cur_;
0052                 if(this->cr_ == ch && !state.eos() && this->nl_ == *state.cur_)
0053                 {
0054                     ++state.cur_;
0055                     if(next.match(state))
0056                     {
0057                         return true;
0058                     }
0059                     --state.cur_;
0060                 }
0061                 else if(next.match(state))
0062                 {
0063                     return true;
0064                 }
0065
0066                 --state.cur_;
0067             }
0068             return false;
0069         }
0070
0071         char_class_type newline() const
0072         {
0073             return this->newline_;
0074         }
0075
0076     private:
0077         char_class_type newline_;
0078         char_type nl_, cr_;
0079     };
0080
0081 }}}
0082
0083 #endif