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- ///////////////////////////////////////////////////////////////////////////////
- // repeat_end_matcher.hpp
- //
- // Copyright 2008 Eric Niebler. Distributed under the Boost
- // Software License, Version 1.0. (See accompanying file
- // LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
- #ifndef BOOST_XPRESSIVE_DETAIL_CORE_MATCHER_REPEAT_END_MATCHER_HPP_EAN_10_04_2005
- #define BOOST_XPRESSIVE_DETAIL_CORE_MATCHER_REPEAT_END_MATCHER_HPP_EAN_10_04_2005
- // MS compatible compilers support #pragma once
- #if defined(_MSC_VER)
- # pragma once
- #endif
- #include <boost/mpl/bool.hpp>
- #include <boost/xpressive/detail/detail_fwd.hpp>
- #include <boost/xpressive/detail/core/quant_style.hpp>
- #include <boost/xpressive/detail/core/state.hpp>
- namespace boost { namespace xpressive { namespace detail
- {
- ///////////////////////////////////////////////////////////////////////////////
- // repeat_end_matcher
- //
- template<typename Greedy>
- struct repeat_end_matcher
- : quant_style<quant_none, 0, false>
- {
- typedef Greedy greedy_type;
- int mark_number_;
- unsigned int min_, max_;
- mutable void const *back_;
- repeat_end_matcher(int mark_nbr, unsigned int min, unsigned int max)
- : mark_number_(mark_nbr)
- , min_(min)
- , max_(max)
- , back_(0)
- {
- }
- template<typename BidiIter, typename Next>
- bool match(match_state<BidiIter> &state, Next const &next) const
- {
- // prevent repeated zero-width sub-matches from causing infinite recursion
- sub_match_impl<BidiIter> &br = state.sub_match(this->mark_number_);
- if(br.zero_width_ && br.begin_ == state.cur_)
- {
- return next.skip_match(state);
- }
- bool old_zero_width = br.zero_width_;
- br.zero_width_ = (br.begin_ == state.cur_);
- if(this->match_(state, next, greedy_type()))
- {
- return true;
- }
- br.zero_width_ = old_zero_width;
- return false;
- }
- // greedy, variable-width quantifier
- template<typename BidiIter, typename Next>
- bool match_(match_state<BidiIter> &state, Next const &next, mpl::true_) const
- {
- sub_match_impl<BidiIter> &br = state.sub_match(this->mark_number_);
- if(this->max_ > br.repeat_count_)
- {
- ++br.repeat_count_;
- // loop back to the expression "pushed" in repeat_begin_matcher::match
- if(next.top_match(state, this->back_))
- {
- return true;
- }
- else if(--br.repeat_count_ < this->min_)
- {
- return false;
- }
- }
- // looping finished, continue matching the rest of the pattern
- return next.skip_match(state);
- }
- // non-greedy, variable-width quantifier
- template<typename BidiIter, typename Next>
- bool match_(match_state<BidiIter> &state, Next const &next, mpl::false_) const
- {
- sub_match_impl<BidiIter> &br = state.sub_match(this->mark_number_);
- if(this->min_ <= br.repeat_count_)
- {
- if(next.skip_match(state))
- {
- return true;
- }
- }
- if(this->max_ > br.repeat_count_)
- {
- ++br.repeat_count_;
- if(next.top_match(state, this->back_))
- {
- return true;
- }
- --br.repeat_count_;
- }
- return false;
- }
- };
- }}}
- #endif
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