ceph/src/boost/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 #ifndef BOOST_SPIRIT_KARMA_OPERATOR_LIST_HPP
   8 #define BOOST_SPIRIT_KARMA_OPERATOR_LIST_HPP
   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 #include <boost/proto/operators.hpp>
  28 #include <boost/proto/tags.hpp>
  29
  30 namespace boost { namespace spirit
  31 {
  32     ///////////////////////////////////////////////////////////////////////////
  33     // Enablers
  34     ///////////////////////////////////////////////////////////////////////////
  35     template <>
  36     struct use_operator<karma::domain, proto::tag::modulus> // enables g % d
  37       : mpl::true_ {};
  38 }}
  39
  40 ///////////////////////////////////////////////////////////////////////////////
  41 namespace boost { namespace spirit { namespace karma
  42 {
  43     template <typename Left, typename Right, typename Strict, typename Derived>
  44     struct base_list : binary_generator<Derived>
  45     {
  46     private:
  47         // iterate over the given container until its exhausted or the embedded
  48         // (left) generator succeeds
  49         template <typename F, typename Attribute>
  50         bool generate_left(F f, Attribute const&, mpl::false_) const
  51         {
  52             // Failing subject generators are just skipped. This allows to
  53             // selectively generate items in the provided attribute.
  54             while (!f.is_at_end())
  55             {
  56                 bool r = !f(left);
  57                 if (r)
  58                     return true;
  59                 if (!f.is_at_end())
  60                     f.next();
  61             }
  62             return false;
  63         }
  64
  65         template <typename F, typename Attribute>
  66         bool generate_left(F f, Attribute const&, mpl::true_) const
  67         {
  68             return !f(left);
  69         }
  70
  71         // There is no way to distinguish a failed generator from a
  72         // generator to be skipped. We assume the user takes responsibility
  73         // for ending the loop if no attribute is specified.
  74         template <typename F>
  75         bool generate_left(F f, unused_type, mpl::false_) const
  76         {
  77             return !f(left);
  78         }
  79
  80     public:
  81         typedef Left left_type;
  82         typedef Right right_type;
  83
  84         typedef mpl::int_<
  85             left_type::properties::value
  86           | right_type::properties::value
  87           | generator_properties::buffering
  88           | generator_properties::counting
  89         > properties;
  90
  91         // Build a std::vector from the LHS's attribute. Note
  92         // that build_std_vector may return unused_type if the
  93         // subject's attribute is an unused_type.
  94         template <typename Context, typename Iterator>
  95         struct attribute
  96           : traits::build_std_vector<
  97                 typename traits::attribute_of<Left, Context, Iterator>::type>
  98         {};
  99
 100         base_list(Left const& left, Right const& right)
 101           : left(left), right(right)
 102         {}
 103
 104         template <
 105             typename OutputIterator, typename Context, typename Delimiter
 106           , typename Attribute>
 107         bool generate(OutputIterator& sink, Context& ctx
 108           , Delimiter const& d, Attribute const& attr) const
 109         {
 110             typedef detail::fail_function<
 111                 OutputIterator, Context, Delimiter
 112             > fail_function;
 113
 114             typedef typename traits::container_iterator<
 115                 typename add_const<Attribute>::type
 116             >::type iterator_type;
 117
 118             typedef
 119                 typename traits::make_indirect_iterator<iterator_type>::type
 120             indirect_iterator_type;
 121             typedef detail::pass_container<
 122                 fail_function, Attribute, indirect_iterator_type, mpl::false_>
 123             pass_container;
 124
 125             iterator_type it = traits::begin(attr);
 126             iterator_type end = traits::end(attr);
 127
 128             pass_container pass(fail_function(sink, ctx, d),
 129                 indirect_iterator_type(it), indirect_iterator_type(end));
 130
 131             if (generate_left(pass, attr, Strict()))
 132             {
 133                 while (!pass.is_at_end())
 134                 {
 135                     // wrap the given output iterator as generate_left might fail
 136                     detail::enable_buffering<OutputIterator> buffering(sink);
 137                     {
 138                         detail::disable_counting<OutputIterator> nocounting(sink);
 139
 140                         if (!right.generate(sink, ctx, d, unused))
 141                             return false;     // shouldn't happen
 142
 143                         if (!generate_left(pass, attr, Strict()))
 144                             break;            // return true as one item succeeded
 145                     }
 146                     buffering.buffer_copy();
 147                 }
 148                 return detail::sink_is_good(sink);
 149             }
 150             return false;
 151         }
 152
 153         template <typename Context>
 154         info what(Context& context) const
 155         {
 156             return info("list",
 157                 std::make_pair(left.what(context), right.what(context)));
 158         }
 159
 160         Left left;
 161         Right right;
 162     };
 163
 164     template <typename Left, typename Right>
 165     struct list
 166       : base_list<Left, Right, mpl::false_, list<Left, Right> >
 167     {
 168         typedef base_list<Left, Right, mpl::false_, list> base_list_;
 169
 170         list(Left const& left, Right const& right)
 171           : base_list_(left, right) {}
 172     };
 173
 174     template <typename Left, typename Right>
 175     struct strict_list
 176       : base_list<Left, Right, mpl::true_, strict_list<Left, Right> >
 177     {
 178         typedef base_list<Left, Right, mpl::true_, strict_list> base_list_;
 179
 180         strict_list (Left const& left, Right const& right)
 181           : base_list_(left, right) {}
 182     };
 183
 184     ///////////////////////////////////////////////////////////////////////////
 185     // Generator generators: make_xxx function (objects)
 186     ///////////////////////////////////////////////////////////////////////////
 187     namespace detail
 188     {
 189         template <typename Subject, bool strict_mode = false>
 190         struct make_list
 191           : make_binary_composite<Subject, list>
 192         {};
 193
 194         template <typename Subject>
 195         struct make_list<Subject, true>
 196           : make_binary_composite<Subject, strict_list>
 197         {};
 198     }
 199
 200     template <typename Subject, typename Modifiers>
 201     struct make_composite<proto::tag::modulus, Subject, Modifiers>
 202       : detail::make_list<Subject, detail::get_stricttag<Modifiers>::value>
 203     {};
 204 }}}
 205
 206 namespace boost { namespace spirit { namespace traits
 207 {
 208     ///////////////////////////////////////////////////////////////////////////
 209     template <typename Left, typename Right>
 210     struct has_semantic_action<karma::list<Left, Right> >
 211       : binary_has_semantic_action<Left, Right> {};
 212
 213     template <typename Left, typename Right>
 214     struct has_semantic_action<karma::strict_list<Left, Right> >
 215       : binary_has_semantic_action<Left, Right> {};
 216
 217     ///////////////////////////////////////////////////////////////////////////
 218     template <typename Left, typename Right, typename Attribute
 219       , typename Context, typename Iterator>
 220     struct handles_container<karma::list<Left, Right>, Attribute
 221           , Context, Iterator>
 222       : mpl::true_ {};
 223
 224     template <typename Left, typename Right, typename Attribute
 225       , typename Context, typename Iterator>
 226     struct handles_container<karma::strict_list<Left, Right>, Attribute
 227           , Context, Iterator>
 228       : mpl::true_ {};
 229 }}}
 230
 231 #endif