ceph/src/boost/libs/spirit/include/boost/spirit/home/karma/operator/list.hpp

   1 //  Copyright (c) 2001-2011 Hartmut Kaiser
   2 //  Copyright (c) 2001-2011 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(SPIRIT_KARMA_LIST_MAY_01_2007_0229PM)
   8 #define SPIRIT_KARMA_LIST_MAY_01_2007_0229PM
   9
  10 #if defined(_MSC_VER)
  11 #pragma once
  12 #endif
  13
  14 #include <boost/spirit/home/karma/domain.hpp>
  15 #include <boost/spirit/home/karma/generator.hpp>
  16 #include <boost/spirit/home/karma/meta_compiler.hpp>
  17 #include <boost/spirit/home/karma/detail/output_iterator.hpp>
  18 #include <boost/spirit/home/karma/detail/indirect_iterator.hpp>
  19 #include <boost/spirit/home/karma/detail/get_stricttag.hpp>
  20 #include <boost/spirit/home/karma/detail/pass_container.hpp>
  21 #include <boost/spirit/home/karma/detail/fail_function.hpp>
  22 #include <boost/spirit/home/support/info.hpp>
  23 #include <boost/spirit/home/support/unused.hpp>
  24 #include <boost/spirit/home/support/container.hpp>
  25 #include <boost/spirit/home/support/handles_container.hpp>
  26 #include <boost/spirit/home/karma/detail/attributes.hpp>
  27
  28 namespace boost { namespace spirit
  29 {
  30     ///////////////////////////////////////////////////////////////////////////
  31     // Enablers
  32     ///////////////////////////////////////////////////////////////////////////
  33     template <>
  34     struct use_operator<karma::domain, proto::tag::modulus> // enables g % d
  35       : mpl::true_ {};
  36 }}
  37
  38 ///////////////////////////////////////////////////////////////////////////////
  39 namespace boost { namespace spirit { namespace karma
  40 {
  41     template <typename Left, typename Right, typename Strict, typename Derived>
  42     struct base_list : binary_generator<Derived>
  43     {
  44     private:
  45         // iterate over the given container until its exhausted or the embedded
  46         // (left) generator succeeds
  47         template <typename F, typename Attribute>
  48         bool generate_left(F f, Attribute const&, mpl::false_) const
  49         {
  50             // Failing subject generators are just skipped. This allows to
  51             // selectively generate items in the provided attribute.
  52             while (!f.is_at_end())
  53             {
  54                 bool r = !f(left);
  55                 if (r)
  56                     return true;
  57                 if (!f.is_at_end())
  58                     f.next();
  59             }
  60             return false;
  61         }
  62
  63         template <typename F, typename Attribute>
  64         bool generate_left(F f, Attribute const&, mpl::true_) const
  65         {
  66             return !f(left);
  67         }
  68
  69         // There is no way to distinguish a failed generator from a
  70         // generator to be skipped. We assume the user takes responsibility
  71         // for ending the loop if no attribute is specified.
  72         template <typename F>
  73         bool generate_left(F f, unused_type, mpl::false_) const
  74         {
  75             return !f(left);
  76         }
  77
  78     public:
  79         typedef Left left_type;
  80         typedef Right right_type;
  81
  82         typedef mpl::int_<
  83             left_type::properties::value
  84           | right_type::properties::value
  85           | generator_properties::buffering
  86           | generator_properties::counting
  87         > properties;
  88
  89         // Build a std::vector from the LHS's attribute. Note
  90         // that build_std_vector may return unused_type if the
  91         // subject's attribute is an unused_type.
  92         template <typename Context, typename Iterator>
  93         struct attribute
  94           : traits::build_std_vector<
  95                 typename traits::attribute_of<Left, Context, Iterator>::type>
  96         {};
  97
  98         base_list(Left const& left, Right const& right)
  99           : left(left), right(right)
 100         {}
 101
 102         template <
 103             typename OutputIterator, typename Context, typename Delimiter
 104           , typename Attribute>
 105         bool generate(OutputIterator& sink, Context& ctx
 106           , Delimiter const& d, Attribute const& attr) const
 107         {
 108             typedef detail::fail_function<
 109                 OutputIterator, Context, Delimiter
 110             > fail_function;
 111
 112             typedef typename traits::container_iterator<
 113                 typename add_const<Attribute>::type
 114             >::type iterator_type;
 115
 116             typedef
 117                 typename traits::make_indirect_iterator<iterator_type>::type
 118             indirect_iterator_type;
 119             typedef detail::pass_container<
 120                 fail_function, Attribute, indirect_iterator_type, mpl::false_>
 121             pass_container;
 122
 123             iterator_type it = traits::begin(attr);
 124             iterator_type end = traits::end(attr);
 125
 126             pass_container pass(fail_function(sink, ctx, d),
 127                 indirect_iterator_type(it), indirect_iterator_type(end));
 128
 129             if (generate_left(pass, attr, Strict()))
 130             {
 131                 while (!pass.is_at_end())
 132                 {
 133                     // wrap the given output iterator as generate_left might fail
 134                     detail::enable_buffering<OutputIterator> buffering(sink);
 135                     {
 136                         detail::disable_counting<OutputIterator> nocounting(sink);
 137
 138                         if (!right.generate(sink, ctx, d, unused))
 139                             return false;     // shouldn't happen
 140
 141                         if (!generate_left(pass, attr, Strict()))
 142                             break;            // return true as one item succeeded
 143                     }
 144                     buffering.buffer_copy();
 145                 }
 146                 return detail::sink_is_good(sink);
 147             }
 148             return false;
 149         }
 150
 151         template <typename Context>
 152         info what(Context& context) const
 153         {
 154             return info("list",
 155                 std::make_pair(left.what(context), right.what(context)));
 156         }
 157
 158         Left left;
 159         Right right;
 160     };
 161
 162     template <typename Left, typename Right>
 163     struct list
 164       : base_list<Left, Right, mpl::false_, list<Left, Right> >
 165     {
 166         typedef base_list<Left, Right, mpl::false_, list> base_list_;
 167
 168         list(Left const& left, Right const& right)
 169           : base_list_(left, right) {}
 170     };
 171
 172     template <typename Left, typename Right>
 173     struct strict_list
 174       : base_list<Left, Right, mpl::true_, strict_list<Left, Right> >
 175     {
 176         typedef base_list<Left, Right, mpl::true_, strict_list> base_list_;
 177
 178         strict_list (Left const& left, Right const& right)
 179           : base_list_(left, right) {}
 180     };
 181
 182     ///////////////////////////////////////////////////////////////////////////
 183     // Generator generators: make_xxx function (objects)
 184     ///////////////////////////////////////////////////////////////////////////
 185     namespace detail
 186     {
 187         template <typename Subject, bool strict_mode = false>
 188         struct make_list
 189           : make_binary_composite<Subject, list>
 190         {};
 191
 192         template <typename Subject>
 193         struct make_list<Subject, true>
 194           : make_binary_composite<Subject, strict_list>
 195         {};
 196     }
 197
 198     template <typename Subject, typename Modifiers>
 199     struct make_composite<proto::tag::modulus, Subject, Modifiers>
 200       : detail::make_list<Subject, detail::get_stricttag<Modifiers>::value>
 201     {};
 202 }}}
 203
 204 namespace boost { namespace spirit { namespace traits
 205 {
 206     ///////////////////////////////////////////////////////////////////////////
 207     template <typename Left, typename Right>
 208     struct has_semantic_action<karma::list<Left, Right> >
 209       : binary_has_semantic_action<Left, Right> {};
 210
 211     template <typename Left, typename Right>
 212     struct has_semantic_action<karma::strict_list<Left, Right> >
 213       : binary_has_semantic_action<Left, Right> {};
 214
 215     ///////////////////////////////////////////////////////////////////////////
 216     template <typename Left, typename Right, typename Attribute
 217       , typename Context, typename Iterator>
 218     struct handles_container<karma::list<Left, Right>, Attribute
 219           , Context, Iterator>
 220       : mpl::true_ {};
 221
 222     template <typename Left, typename Right, typename Attribute
 223       , typename Context, typename Iterator>
 224     struct handles_container<karma::strict_list<Left, Right>, Attribute
 225           , Context, Iterator>
 226       : mpl::true_ {};
 227 }}}
 228
 229 #endif