/////////////////////////////////////////////////////////////////////////////// | |
// 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) && (_MSC_VER >= 1020) | |
# 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 |