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402 lines
13 KiB
402 lines
13 KiB
3 years ago
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///////////////////////////////////////////////////////////////////////////////
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// state.hpp
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//
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// Copyright 2008 Eric Niebler. Distributed under the Boost
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// Software License, Version 1.0. (See accompanying file
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// LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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#ifndef BOOST_XPRESSIVE_DETAIL_CORE_STATE_HPP_EAN_10_04_2005
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#define BOOST_XPRESSIVE_DETAIL_CORE_STATE_HPP_EAN_10_04_2005
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// MS compatible compilers support #pragma once
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#if defined(_MSC_VER)
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# pragma once
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#endif
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#include <boost/noncopyable.hpp>
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#include <boost/xpressive/detail/detail_fwd.hpp>
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#include <boost/xpressive/detail/core/access.hpp>
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#include <boost/xpressive/detail/core/action.hpp>
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#include <boost/xpressive/detail/core/sub_match_vector.hpp>
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#include <boost/xpressive/detail/utility/sequence_stack.hpp>
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#include <boost/xpressive/detail/core/regex_impl.hpp>
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#include <boost/xpressive/regex_constants.hpp>
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namespace boost { namespace xpressive { namespace detail
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{
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///////////////////////////////////////////////////////////////////////////////
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// match_context
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//
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template<typename BidiIter>
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struct match_context
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{
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typedef typename iterator_value<BidiIter>::type char_type;
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match_context()
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: results_ptr_(0)
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, prev_context_(0)
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, next_ptr_(0)
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, traits_(0)
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{
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}
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// pointer to the current match results, passed to actions as a parameter.
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match_results<BidiIter> *results_ptr_;
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// The previous match context, if this match_context corresponds to a nested regex invocation
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match_context<BidiIter> *prev_context_;
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// If this is a nested match, the "next" sub-expression to execute after the nested match
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matchable<BidiIter> const *next_ptr_;
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// A pointer to the current traits object
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detail::traits<char_type> const *traits_;
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};
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///////////////////////////////////////////////////////////////////////////////
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// attr_context
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//
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struct attr_context
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{
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// Slots for holding type-erased pointers to attributes
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void const **attr_slots_;
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// The previous attr context, if one exists
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attr_context *prev_attr_context_;
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};
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///////////////////////////////////////////////////////////////////////////////
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// match_flags
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//
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struct match_flags
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{
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bool match_all_;
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bool match_prev_avail_;
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bool match_bol_;
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bool match_eol_;
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bool match_not_bow_;
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bool match_not_eow_;
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bool match_not_null_;
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bool match_continuous_;
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bool match_partial_;
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explicit match_flags(regex_constants::match_flag_type flags)
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: match_all_(false)
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, match_prev_avail_(0 != (flags & regex_constants::match_prev_avail))
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, match_bol_(match_prev_avail_ || 0 == (flags & regex_constants::match_not_bol))
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, match_eol_(0 == (flags & regex_constants::match_not_eol))
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, match_not_bow_(!match_prev_avail_ && 0 != (flags & regex_constants::match_not_bow))
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, match_not_eow_(0 != (flags & regex_constants::match_not_eow))
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, match_not_null_(0 != (flags & regex_constants::match_not_null))
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, match_continuous_(0 != (flags & regex_constants::match_continuous))
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, match_partial_(0 != (flags & regex_constants::match_partial))
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{
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}
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};
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///////////////////////////////////////////////////////////////////////////////
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// match_state
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//
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template<typename BidiIter>
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struct match_state
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: noncopyable
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{
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typedef BidiIter iterator;
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typedef core_access<BidiIter> access;
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typedef detail::match_context<BidiIter> match_context;
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typedef detail::results_extras<BidiIter> results_extras;
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typedef detail::regex_impl<BidiIter> regex_impl;
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typedef detail::matchable<BidiIter> matchable;
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typedef xpressive::match_results<BidiIter> match_results;
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typedef detail::sub_match_impl<BidiIter> sub_match_impl;
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typedef detail::actionable actionable;
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BidiIter cur_;
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sub_match_impl *sub_matches_;
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std::size_t mark_count_;
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BidiIter begin_;
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BidiIter end_;
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match_flags flags_;
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bool found_partial_match_;
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match_context context_;
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results_extras *extras_;
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actionable action_list_;
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actionable const **action_list_tail_;
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action_args_type *action_args_;
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attr_context attr_context_;
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BidiIter next_search_;
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///////////////////////////////////////////////////////////////////////////////
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//
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match_state
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(
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BidiIter begin
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, BidiIter end
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, match_results &what
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, regex_impl const &impl
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, regex_constants::match_flag_type flags
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)
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: cur_(begin)
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, sub_matches_(0)
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, mark_count_(0)
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, begin_(begin)
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, end_(end)
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, flags_(flags)
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, found_partial_match_(false)
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, context_() // zero-initializes the fields of context_
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, extras_(&core_access<BidiIter>::get_extras(what))
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, action_list_()
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, action_list_tail_(&action_list_.next)
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, action_args_(&core_access<BidiIter>::get_action_args(what))
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, attr_context_() // zero-initializes the fields of attr_context_
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, next_search_(begin)
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{
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// reclaim any cached memory in the match_results struct
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this->extras_->sub_match_stack_.unwind();
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// initialize the context_ struct
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this->init_(impl, what);
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// move all the nested match_results structs into the match_results cache
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this->extras_->results_cache_.reclaim_all(access::get_nested_results(what));
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}
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///////////////////////////////////////////////////////////////////////////////
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// reset
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void reset(match_results &what, regex_impl const &impl)
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{
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this->extras_ = &core_access<BidiIter>::get_extras(what);
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this->action_list_.next = 0;
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this->action_list_tail_ = &action_list_.next;
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this->action_args_ = &core_access<BidiIter>::get_action_args(what);
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this->attr_context_ = attr_context();
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this->context_.prev_context_ = 0;
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this->found_partial_match_ = false;
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this->extras_->sub_match_stack_.unwind();
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this->init_(impl, what);
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this->extras_->results_cache_.reclaim_all(access::get_nested_results(what));
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}
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///////////////////////////////////////////////////////////////////////////////
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// push_context
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// called to prepare the state object for a regex match
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match_context push_context(regex_impl const &impl, matchable const &next, match_context &prev)
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{
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// save state
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match_context context = this->context_;
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// create a new nested match_results for this regex
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nested_results<BidiIter> &nested = access::get_nested_results(*context.results_ptr_);
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match_results &what = this->extras_->results_cache_.append_new(nested);
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// (re)initialize the match context
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this->init_(impl, what);
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// create a linked list of match_context structs
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this->context_.prev_context_ = &prev;
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this->context_.next_ptr_ = &next;
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// record the start of the zero-th sub-match
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this->sub_matches_[0].begin_ = this->cur_;
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return context;
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}
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///////////////////////////////////////////////////////////////////////////////
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// pop_context
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// called after a nested match failed to restore the context
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bool pop_context(regex_impl const &impl, bool success)
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{
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match_context &context = *this->context_.prev_context_;
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if(!success)
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{
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match_results &what = *context.results_ptr_;
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this->uninit_(impl, what);
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// send the match_results struct back to the cache
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nested_results<BidiIter> &nested = access::get_nested_results(what);
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this->extras_->results_cache_.reclaim_last(nested);
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}
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// restore the state
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this->context_ = context;
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match_results &results = *this->context_.results_ptr_;
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this->sub_matches_ = access::get_sub_matches(access::get_sub_match_vector(results));
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this->mark_count_ = results.size();
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return success;
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}
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///////////////////////////////////////////////////////////////////////////////
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// swap_context
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void swap_context(match_context &context)
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{
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std::swap(this->context_, context);
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match_results &results = *this->context_.results_ptr_;
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this->sub_matches_ = access::get_sub_matches(access::get_sub_match_vector(results));
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this->mark_count_ = results.size();
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}
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// beginning of buffer
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bool bos() const
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{
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return this->cur_ == this->begin_;
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}
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// end of buffer
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bool eos()
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{
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return this->cur_ == this->end_ && this->found_partial_match();
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}
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// is this the regex that is currently executing?
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bool is_active_regex(regex_impl const &impl) const
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{
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return impl.xpr_.get() == this->context_.results_ptr_->regex_id();
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}
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// fetch the n-th sub_match
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sub_match_impl &sub_match(int n)
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{
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return this->sub_matches_[n];
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}
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// called when a partial match has succeeded
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void set_partial_match()
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{
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sub_match_impl &sub0 = this->sub_match(0);
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sub0.first = sub0.begin_;
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sub0.second = this->end_;
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sub0.matched = false;
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}
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template<typename Traits>
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Traits const &get_traits() const
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{
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return static_cast<traits_holder<Traits> const *>(this->context_.traits_)->traits();
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}
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private:
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void init_(regex_impl const &impl, match_results &what)
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{
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regex_id_type const id = impl.xpr_.get();
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std::size_t const total_mark_count = impl.mark_count_ + impl.hidden_mark_count_ + 1;
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// initialize the context and the sub_match vector
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this->context_.results_ptr_ = &what;
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this->context_.traits_ = impl.traits_.get();
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this->mark_count_ = impl.mark_count_ + 1;
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this->sub_matches_ = this->extras_->sub_match_stack_.push_sequence(total_mark_count, sub_match_impl(begin_), detail::fill);
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this->sub_matches_ += impl.hidden_mark_count_;
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// initialize the match_results struct
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access::init_match_results(what, id, impl.traits_, this->sub_matches_, this->mark_count_, impl.named_marks_);
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}
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void uninit_(regex_impl const &impl, match_results &)
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{
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extras_->sub_match_stack_.unwind_to(this->sub_matches_ - impl.hidden_mark_count_);
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}
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bool found_partial_match()
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{
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this->found_partial_match_ = true;
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return true;
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}
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};
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///////////////////////////////////////////////////////////////////////////////
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// memento
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//
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template<typename BidiIter>
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struct memento
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{
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sub_match_impl<BidiIter> *old_sub_matches_;
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std::size_t nested_results_count_;
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actionable const *action_list_head_;
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actionable const **action_list_tail_;
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attr_context attr_context_;
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};
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///////////////////////////////////////////////////////////////////////////////
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// save_sub_matches
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//
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template<typename BidiIter>
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inline memento<BidiIter> save_sub_matches(match_state<BidiIter> &state)
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{
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memento<BidiIter> mem =
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{
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state.extras_->sub_match_stack_.push_sequence(state.mark_count_, sub_match_impl<BidiIter>(state.begin_))
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, state.context_.results_ptr_->nested_results().size()
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, state.action_list_.next
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, state.action_list_tail_
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, state.attr_context_
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};
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state.action_list_.next = 0;
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state.action_list_tail_ = &state.action_list_.next;
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std::copy(state.sub_matches_, state.sub_matches_ + state.mark_count_, mem.old_sub_matches_);
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return mem;
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}
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///////////////////////////////////////////////////////////////////////////////
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// restore_action_queue
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//
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template<typename BidiIter>
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inline void restore_action_queue(memento<BidiIter> const &mem, match_state<BidiIter> &state)
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{
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state.action_list_.next = mem.action_list_head_;
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state.action_list_tail_ = mem.action_list_tail_;
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*state.action_list_tail_ = 0;
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}
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///////////////////////////////////////////////////////////////////////////////
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// restore_sub_matches
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//
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template<typename BidiIter>
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inline void restore_sub_matches(memento<BidiIter> const &mem, match_state<BidiIter> &state)
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{
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typedef core_access<BidiIter> access;
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nested_results<BidiIter> &nested = access::get_nested_results(*state.context_.results_ptr_);
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std::size_t count = nested.size() - mem.nested_results_count_;
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state.extras_->results_cache_.reclaim_last_n(nested, count);
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std::copy(mem.old_sub_matches_, mem.old_sub_matches_ + state.mark_count_, state.sub_matches_);
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state.extras_->sub_match_stack_.unwind_to(mem.old_sub_matches_);
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state.attr_context_ = mem.attr_context_;
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}
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///////////////////////////////////////////////////////////////////////////////
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// reclaim_sub_matches
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//
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template<typename BidiIter>
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inline void reclaim_sub_matches(memento<BidiIter> const &mem, match_state<BidiIter> &state, bool success)
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{
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std::size_t count = state.context_.results_ptr_->nested_results().size() - mem.nested_results_count_;
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if(count == 0)
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{
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state.extras_->sub_match_stack_.unwind_to(mem.old_sub_matches_);
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}
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// else we have we must orphan this block of backrefs because we are using the stack
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// space above it.
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if(!success)
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{
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state.attr_context_ = mem.attr_context_;
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}
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}
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///////////////////////////////////////////////////////////////////////////////
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// traits_cast
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//
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template<typename Traits, typename BidiIter>
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inline Traits const &traits_cast(match_state<BidiIter> const &state)
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{
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return state.template get_traits<Traits>();
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}
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}}} // namespace boost::xpressive::detail
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#endif
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