ceph/src/boost/libs/xpressive/include/boost/xpressive/detail/core/matcher/optional_matcher.hpp

   1 ///////////////////////////////////////////////////////////////////////////////
   2 // optional_matcher.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_MATCHER_OPTIONAL_MATCHER_HPP_EAN_10_04_2005
   9 #define BOOST_XPRESSIVE_DETAIL_CORE_MATCHER_OPTIONAL_MATCHER_HPP_EAN_10_04_2005
  10
  11 // MS compatible compilers support #pragma once
  12 #if defined(_MSC_VER)
  13 # pragma once
  14 #endif
  15
  16 #include <boost/mpl/bool.hpp>
  17 #include <boost/xpressive/detail/detail_fwd.hpp>
  18 #include <boost/xpressive/detail/core/quant_style.hpp>
  19 #include <boost/xpressive/detail/core/state.hpp>
  20
  21 namespace boost { namespace xpressive { namespace detail
  22 {
  23
  24     ///////////////////////////////////////////////////////////////////////////////
  25     // optional_matcher
  26     template<typename Xpr, typename Greedy>
  27     struct optional_matcher
  28       : quant_style<quant_variable_width, unknown_width::value, Xpr::pure>
  29     {
  30         Xpr xpr_;
  31
  32         explicit optional_matcher(Xpr const &xpr)
  33           : xpr_(xpr)
  34         {
  35         }
  36
  37         template<typename BidiIter, typename Next>
  38         bool match(match_state<BidiIter> &state, Next const &next) const
  39         {
  40             return this->match_(state, next, Greedy());
  41         }
  42
  43     private:
  44         template<typename BidiIter, typename Next>
  45         bool match_(match_state<BidiIter> &state, Next const &next, mpl::true_) const // Greedy
  46         {
  47             return this->xpr_.BOOST_NESTED_TEMPLATE push_match<Next>(state)
  48                 || next.match(state);
  49         }
  50
  51         template<typename BidiIter, typename Next>
  52         bool match_(match_state<BidiIter> &state, Next const &next, mpl::false_) const // Non-greedy
  53         {
  54             return next.match(state)
  55                 || this->xpr_.BOOST_NESTED_TEMPLATE push_match<Next>(state);
  56         }
  57
  58         optional_matcher &operator =(optional_matcher const &);
  59     };
  60
  61     ///////////////////////////////////////////////////////////////////////////////
  62     // optional_mark_matcher
  63     template<typename BidiIter, typename Next>
  64     inline bool match_next(match_state<BidiIter> &state, Next const &next, int mark_number)
  65     {
  66         sub_match_impl<BidiIter> &br = state.sub_match(mark_number);
  67
  68         bool old_matched = br.matched;
  69         br.matched = false;
  70
  71         if(next.match(state))
  72         {
  73             return true;
  74         }
  75
  76         br.matched = old_matched;
  77         return false;
  78     }
  79
  80     ///////////////////////////////////////////////////////////////////////////////
  81     // optional_mark_matcher
  82     template<typename Xpr, typename Greedy>
  83     struct optional_mark_matcher
  84       : quant_style<quant_variable_width, unknown_width::value, Xpr::pure>
  85     {
  86         Xpr xpr_;
  87         int mark_number_;
  88
  89         explicit optional_mark_matcher(Xpr const &xpr, int mark_number)
  90           : xpr_(xpr)
  91           , mark_number_(mark_number)
  92         {
  93         }
  94
  95         template<typename BidiIter, typename Next>
  96         bool match(match_state<BidiIter> &state, Next const &next) const
  97         {
  98             return this->match_(state, next, Greedy());
  99         }
 100
 101     private:
 102         template<typename BidiIter, typename Next>
 103         bool match_(match_state<BidiIter> &state, Next const &next, mpl::true_) const // Greedy
 104         {
 105             return this->xpr_.BOOST_NESTED_TEMPLATE push_match<Next>(state)
 106                 || match_next(state, next, this->mark_number_);
 107         }
 108
 109         template<typename BidiIter, typename Next>
 110         bool match_(match_state<BidiIter> &state, Next const &next, mpl::false_) const // Non-greedy
 111         {
 112             return match_next(state, next, this->mark_number_)
 113                 || this->xpr_.BOOST_NESTED_TEMPLATE push_match<Next>(state);
 114         }
 115
 116         optional_mark_matcher &operator =(optional_mark_matcher const &);
 117     };
 118
 119 }}}
 120
 121 #endif