ceph/src/boost/boost/spirit/home/x3/core/skip_over.hpp

   1 /*=============================================================================
   2     Copyright (c) 2001-2014 Joel de Guzman
   3
   4     Distributed under the Boost Software License, Version 1.0. (See accompanying
   5     file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   6 ==============================================================================*/
   7 #if !defined(BOOST_SPIRIT_X3_SKIP_APRIL_16_2006_0625PM)
   8 #define BOOST_SPIRIT_X3_SKIP_APRIL_16_2006_0625PM
   9
  10 #include <boost/spirit/home/x3/support/unused.hpp>
  11 #include <boost/spirit/home/x3/support/context.hpp>
  12 #include <boost/spirit/home/x3/support/traits/attribute_category.hpp>
  13 #include <boost/mpl/bool.hpp>
  14 #include <boost/mpl/not.hpp>
  15 #include <boost/type_traits/remove_cv.hpp>
  16 #include <boost/type_traits/remove_reference.hpp>
  17 #include <boost/utility/declval.hpp>
  18
  19 namespace boost { namespace spirit { namespace x3
  20 {
  21     ///////////////////////////////////////////////////////////////////////////
  22     // Move the /first/ iterator to the first non-matching position
  23     // given a skip-parser. The function is a no-op if unused_type or
  24     // unused_skipper is passed as the skip-parser.
  25     ///////////////////////////////////////////////////////////////////////////
  26     template <typename Skipper>
  27     struct unused_skipper : unused_type
  28     {
  29         unused_skipper(Skipper const& skipper)
  30           : skipper(skipper) {}
  31         Skipper const& skipper;
  32     };
  33
  34     namespace detail
  35     {
  36         template <typename Skipper>
  37         struct is_unused_skipper
  38           : mpl::false_ {};
  39
  40         template <typename Skipper>
  41         struct is_unused_skipper<unused_skipper<Skipper>>
  42           : mpl::true_ {};
  43
  44         template <>
  45         struct is_unused_skipper<unused_type>
  46           : mpl::true_ {};
  47
  48         template <typename Skipper>
  49         inline Skipper const&
  50         get_unused_skipper(Skipper const& skipper)
  51         {
  52             return skipper;
  53         }
  54         template <typename Skipper>
  55         inline Skipper const&
  56         get_unused_skipper(unused_skipper<Skipper> const& unused_skipper)
  57         {
  58             return unused_skipper.skipper;
  59         }
  60
  61         template <typename Iterator, typename Skipper>
  62         inline void skip_over(
  63             Iterator& first, Iterator const& last, Skipper const& skipper)
  64         {
  65             while (first != last && skipper.parse(first, last, unused, unused, unused))
  66                 /***/;
  67         }
  68
  69         template <typename Iterator>
  70         inline void skip_over(Iterator&, Iterator const&, unused_type)
  71         {
  72         }
  73
  74         template <typename Iterator, typename Skipper>
  75         inline void skip_over(
  76             Iterator&, Iterator const&, unused_skipper<Skipper> const&)
  77         {
  78         }
  79     }
  80
  81     // this tag is used to find the skipper from the context
  82     struct skipper_tag;
  83
  84     template <typename Context>
  85     struct has_skipper
  86       : mpl::not_<detail::is_unused_skipper<
  87             typename remove_cv<typename remove_reference<
  88                 decltype(x3::get<skipper_tag>(boost::declval<Context>()))
  89             >::type>::type
  90         >> {};
  91
  92     template <typename Iterator, typename Context>
  93     inline void skip_over(
  94         Iterator& first, Iterator const& last, Context const& context)
  95     {
  96         detail::skip_over(first, last, x3::get<skipper_tag>(context));
  97     }
  98 }}}
  99
 100 #endif