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117 lines
3.4 KiB
117 lines
3.4 KiB
///////////////////////////////////////////////////////////////////////////////
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// optimize.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_OPTIMIZE_HPP_EAN_10_04_2005
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#define BOOST_XPRESSIVE_DETAIL_CORE_OPTIMIZE_HPP_EAN_10_04_2005
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#include <string>
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#include <utility>
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#include <boost/mpl/bool.hpp>
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#include <boost/intrusive_ptr.hpp>
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#include <boost/iterator/iterator_traits.hpp>
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#include <boost/xpressive/detail/core/finder.hpp>
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#include <boost/xpressive/detail/core/linker.hpp>
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#include <boost/xpressive/detail/core/peeker.hpp>
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#include <boost/xpressive/detail/core/regex_impl.hpp>
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namespace boost { namespace xpressive { namespace detail
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{
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///////////////////////////////////////////////////////////////////////////////
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// optimize_regex
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//
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template<typename BidiIter, typename Traits>
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intrusive_ptr<finder<BidiIter> > optimize_regex
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(
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xpression_peeker<typename iterator_value<BidiIter>::type> const &peeker
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, Traits const &tr
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, mpl::false_
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)
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{
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if(peeker.line_start())
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{
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return intrusive_ptr<finder<BidiIter> >
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(
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new line_start_finder<BidiIter, Traits>(tr)
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);
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}
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else if(peeker.leading_simple_repeat())
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{
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return intrusive_ptr<finder<BidiIter> >
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(
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new leading_simple_repeat_finder<BidiIter>()
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);
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}
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else if(256 != peeker.bitset().count())
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{
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return intrusive_ptr<finder<BidiIter> >
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(
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new hash_peek_finder<BidiIter, Traits>(peeker.bitset())
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);
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}
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return intrusive_ptr<finder<BidiIter> >();
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}
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///////////////////////////////////////////////////////////////////////////////
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// optimize_regex
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//
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template<typename BidiIter, typename Traits>
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intrusive_ptr<finder<BidiIter> > optimize_regex
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(
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xpression_peeker<typename iterator_value<BidiIter>::type> const &peeker
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, Traits const &tr
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, mpl::true_
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)
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{
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typedef typename iterator_value<BidiIter>::type char_type;
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// if we have a leading string literal, initialize a boyer-moore struct with it
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peeker_string<char_type> const &str = peeker.get_string();
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if(str.begin_ != str.end_)
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{
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BOOST_ASSERT(1 == peeker.bitset().count());
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return intrusive_ptr<finder<BidiIter> >
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(
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new boyer_moore_finder<BidiIter, Traits>(str.begin_, str.end_, tr, str.icase_)
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);
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}
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return optimize_regex<BidiIter>(peeker, tr, mpl::false_());
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}
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///////////////////////////////////////////////////////////////////////////////
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// common_compile
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//
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template<typename BidiIter, typename Traits>
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void common_compile
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(
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intrusive_ptr<matchable_ex<BidiIter> const> const ®ex
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, regex_impl<BidiIter> &impl
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, Traits const &tr
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)
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{
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typedef typename iterator_value<BidiIter>::type char_type;
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// "link" the regex
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xpression_linker<char_type> linker(tr);
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regex->link(linker);
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// "peek" into the compiled regex to see if there are optimization opportunities
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hash_peek_bitset<char_type> bset;
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xpression_peeker<char_type> peeker(bset, tr, linker.has_backrefs());
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regex->peek(peeker);
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// optimization: get the peek chars OR the boyer-moore search string
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impl.finder_ = optimize_regex<BidiIter>(peeker, tr, is_random<BidiIter>());
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impl.xpr_ = regex;
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}
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}}} // namespace boost::xpressive
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#endif
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