ceph/src/boost/libs/xpressive/include/boost/xpressive/detail/core/optimize.hpp

   1 ///////////////////////////////////////////////////////////////////////////////
   2 // optimize.hpp
   3 //
   4 //  Copyright 2008 Eric Niebler. Distributed under the Boost
   5 //  Software License, Version 1.0. (See accompanying file
   6 //  LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   7
   8 #ifndef BOOST_XPRESSIVE_DETAIL_CORE_OPTIMIZE_HPP_EAN_10_04_2005
   9 #define BOOST_XPRESSIVE_DETAIL_CORE_OPTIMIZE_HPP_EAN_10_04_2005
  10
  11 #include <string>
  12 #include <utility>
  13 #include <boost/mpl/bool.hpp>
  14 #include <boost/intrusive_ptr.hpp>
  15 #include <boost/iterator/iterator_traits.hpp>
  16 #include <boost/xpressive/detail/core/finder.hpp>
  17 #include <boost/xpressive/detail/core/linker.hpp>
  18 #include <boost/xpressive/detail/core/peeker.hpp>
  19 #include <boost/xpressive/detail/core/regex_impl.hpp>
  20
  21 namespace boost { namespace xpressive { namespace detail
  22 {
  23
  24 ///////////////////////////////////////////////////////////////////////////////
  25 // optimize_regex
  26 //
  27 template<typename BidiIter, typename Traits>
  28 intrusive_ptr<finder<BidiIter> > optimize_regex
  29 (
  30     xpression_peeker<typename iterator_value<BidiIter>::type> const &peeker
  31   , Traits const &tr
  32   , mpl::false_
  33 )
  34 {
  35     if(peeker.line_start())
  36     {
  37         return intrusive_ptr<finder<BidiIter> >
  38         (
  39             new line_start_finder<BidiIter, Traits>(tr)
  40         );
  41     }
  42     else if(peeker.leading_simple_repeat())
  43     {
  44         return intrusive_ptr<finder<BidiIter> >
  45         (
  46             new leading_simple_repeat_finder<BidiIter>()
  47         );
  48     }
  49     else if(256 != peeker.bitset().count())
  50     {
  51         return intrusive_ptr<finder<BidiIter> >
  52         (
  53             new hash_peek_finder<BidiIter, Traits>(peeker.bitset())
  54         );
  55     }
  56
  57     return intrusive_ptr<finder<BidiIter> >();
  58 }
  59
  60 ///////////////////////////////////////////////////////////////////////////////
  61 // optimize_regex
  62 //
  63 template<typename BidiIter, typename Traits>
  64 intrusive_ptr<finder<BidiIter> > optimize_regex
  65 (
  66     xpression_peeker<typename iterator_value<BidiIter>::type> const &peeker
  67   , Traits const &tr
  68   , mpl::true_
  69 )
  70 {
  71     typedef typename iterator_value<BidiIter>::type char_type;
  72
  73     // if we have a leading string literal, initialize a boyer-moore struct with it
  74     peeker_string<char_type> const &str = peeker.get_string();
  75     if(str.begin_ != str.end_)
  76     {
  77         BOOST_ASSERT(1 == peeker.bitset().count());
  78         return intrusive_ptr<finder<BidiIter> >
  79         (
  80             new boyer_moore_finder<BidiIter, Traits>(str.begin_, str.end_, tr, str.icase_)
  81         );
  82     }
  83
  84     return optimize_regex<BidiIter>(peeker, tr, mpl::false_());
  85 }
  86
  87 ///////////////////////////////////////////////////////////////////////////////
  88 // common_compile
  89 //
  90 template<typename BidiIter, typename Traits>
  91 void common_compile
  92 (
  93     intrusive_ptr<matchable_ex<BidiIter> const> const &regex
  94   , regex_impl<BidiIter> &impl
  95   , Traits const &tr
  96 )
  97 {
  98     typedef typename iterator_value<BidiIter>::type char_type;
  99
 100     // "link" the regex
 101     xpression_linker<char_type> linker(tr);
 102     regex->link(linker);
 103
 104     // "peek" into the compiled regex to see if there are optimization opportunities
 105     hash_peek_bitset<char_type> bset;
 106     xpression_peeker<char_type> peeker(bset, tr, linker.has_backrefs());
 107     regex->peek(peeker);
 108
 109     // optimization: get the peek chars OR the boyer-moore search string
 110     impl.finder_ = optimize_regex<BidiIter>(peeker, tr, is_random<BidiIter>());
 111     impl.xpr_ = regex;
 112 }
 113
 114 }}} // namespace boost::xpressive
 115
 116 #endif