/Src/Dependencies/Boost/boost/spirit/home/karma/detail/pass_container.hpp
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1/*============================================================================= 2 Copyright (c) 2001-2011 Hartmut Kaiser 3 Copyright (c) 2001-2011 Joel de Guzman 4 5 Distributed under the Boost Software License, Version 1.0. (See accompanying 6 file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) 7=============================================================================*/ 8#if !defined(SPIRIT_PASS_CONTAINER_MAR_15_2009_0114PM) 9#define SPIRIT_PASS_CONTAINER_MAR_15_2009_0114PM 10 11#if defined(_MSC_VER) 12#pragma once 13#endif 14 15#include <boost/spirit/home/karma/detail/attributes.hpp> 16#include <boost/spirit/home/support/container.hpp> 17#include <boost/spirit/home/support/handles_container.hpp> 18#include <boost/spirit/home/support/detail/hold_any.hpp> 19#include <boost/type_traits/is_base_of.hpp> 20#include <boost/type_traits/is_convertible.hpp> 21#include <boost/mpl/bool.hpp> 22#include <boost/mpl/and.hpp> 23#include <boost/mpl/or.hpp> 24#include <boost/preprocessor/cat.hpp> 25#include <boost/preprocessor/repetition/repeat.hpp> 26#include <boost/range/iterator_range.hpp> 27#include <boost/fusion/include/deduce_sequence.hpp> 28 29#include <boost/mpl/print.hpp> 30 31namespace boost { namespace spirit { namespace karma { namespace detail 32{ 33 // Helper meta-function allowing to evaluate weak substitutability and 34 // negate the result if the predicate (Sequence) is not true 35 template <typename Sequence, typename Attribute, typename ValueType> 36 struct negate_weak_substitute_if_not 37 : mpl::if_< 38 Sequence 39 , typename traits::is_weak_substitute<Attribute, ValueType>::type 40 , typename mpl::not_< 41 traits::is_weak_substitute<Attribute, ValueType> 42 >::type> 43 {}; 44 45 // pass_through_container: utility to check decide whether a provided 46 // container attribute needs to be passed through to the current component 47 // or of we need to split the container by passing along instances of its 48 // value type 49 50 // if the expected attribute of the current component is neither a Fusion 51 // sequence nor a container, we will pass through the provided container 52 // only if its value type is not compatible with the component 53 template <typename Container, typename ValueType, typename Attribute 54 , typename Sequence, typename Enable = void> 55 struct pass_through_container_base 56 : negate_weak_substitute_if_not<Sequence, ValueType, Attribute> 57 {}; 58 59 // Specialization for fusion sequences, in this case we check whether all 60 // the types in the sequence are convertible to the lhs attribute. 61 // 62 // We return false if the rhs attribute itself is a fusion sequence, which 63 // is compatible with the LHS sequence (we want to pass through this 64 // attribute without it being split apart). 65 template <typename Container, typename ValueType, typename Attribute 66 , typename Sequence = mpl::true_> 67 struct not_compatible_element 68 : mpl::and_< 69 negate_weak_substitute_if_not<Sequence, Container, Attribute> 70 , negate_weak_substitute_if_not<Sequence, ValueType, Attribute> > 71 {}; 72 73 // If the value type of the container is not a Fusion sequence, we pass 74 // through the container if each of the elements of the Attribute 75 // sequence is compatible with either the container or its value type. 76 template <typename Container, typename ValueType, typename Attribute 77 , typename Sequence 78 , bool IsSequence = fusion::traits::is_sequence<ValueType>::value> 79 struct pass_through_container_fusion_sequence 80 { 81 typedef typename mpl::find_if< 82 Attribute, not_compatible_element<Container, ValueType, mpl::_1> 83 >::type iter; 84 typedef typename mpl::end<Attribute>::type end; 85 86 typedef typename is_same<iter, end>::type type; 87 }; 88 89 // If both, the Attribute and the value type of the provided container 90 // are Fusion sequences, we pass the container only if the two 91 // sequences are not compatible. 92 template <typename Container, typename ValueType, typename Attribute 93 , typename Sequence> 94 struct pass_through_container_fusion_sequence< 95 Container, ValueType, Attribute, Sequence, true> 96 { 97 typedef typename mpl::find_if< 98 Attribute 99 , not_compatible_element<Container, ValueType, mpl::_1, Sequence> 100 >::type iter; 101 typedef typename mpl::end<Attribute>::type end; 102 103 typedef typename is_same<iter, end>::type type; 104 }; 105 106 template <typename Container, typename ValueType, typename Attribute 107 , typename Sequence> 108 struct pass_through_container_base<Container, ValueType, Attribute 109 , Sequence 110 , typename enable_if<fusion::traits::is_sequence<Attribute> >::type> 111 : pass_through_container_fusion_sequence< 112 Container, ValueType, Attribute, Sequence> 113 {}; 114 115 // Specialization for containers 116 // 117 // If the value type of the attribute of the current component is not 118 // a Fusion sequence, we have to pass through the provided container if 119 // both are compatible. 120 template <typename Container, typename ValueType, typename Attribute 121 , typename Sequence, typename AttributeValueType 122 , bool IsSequence = fusion::traits::is_sequence<AttributeValueType>::value> 123 struct pass_through_container_container 124 : mpl::or_< 125 traits::is_weak_substitute<Container, Attribute> 126 , traits::is_weak_substitute<Container, AttributeValueType> > 127 {}; 128 129 // If the value type of the exposed container attribute is a Fusion 130 // sequence, we use the already existing logic for those. 131 template <typename Container, typename ValueType, typename Attribute 132 , typename Sequence, typename AttributeValueType> 133 struct pass_through_container_container< 134 Container, ValueType, Attribute, Sequence, AttributeValueType, true> 135 : pass_through_container_fusion_sequence< 136 Container, ValueType, AttributeValueType, Sequence> 137 {}; 138 139 template <typename Container, typename ValueType, typename Attribute 140 , typename Sequence> 141 struct pass_through_container_base<Container, ValueType, Attribute 142 , Sequence 143 , typename enable_if<traits::is_container<Attribute> >::type> 144 : detail::pass_through_container_container< 145 Container, ValueType, Attribute, Sequence 146 , typename traits::container_value<Attribute>::type> 147 {}; 148 149 // Specialization for exposed optional attributes 150 // 151 // If the type embedded in the exposed optional is not a Fusion 152 // sequence we pass through the container attribute if it is compatible 153 // either to the optionals embedded type or to the containers value 154 // type. 155 template <typename Container, typename ValueType, typename Attribute 156 , typename Sequence 157 , bool IsSequence = fusion::traits::is_sequence<Attribute>::value> 158 struct pass_through_container_optional 159 : mpl::or_< 160 traits::is_weak_substitute<Container, Attribute> 161 , traits::is_weak_substitute<ValueType, Attribute> > 162 {}; 163 164 // If the embedded type of the exposed optional attribute is a Fusion 165 // sequence, we use the already existing logic for those. 166 template <typename Container, typename ValueType, typename Attribute 167 , typename Sequence> 168 struct pass_through_container_optional< 169 Container, ValueType, Attribute, Sequence, true> 170 : pass_through_container_fusion_sequence< 171 Container, ValueType, Attribute, Sequence> 172 {}; 173 174 /////////////////////////////////////////////////////////////////////////// 175 template <typename Container, typename ValueType, typename Attribute 176 , typename Sequence> 177 struct pass_through_container 178 : pass_through_container_base<Container, ValueType, Attribute, Sequence> 179 {}; 180 181 // Handle optional attributes 182 template <typename Container, typename ValueType, typename Attribute 183 , typename Sequence> 184 struct pass_through_container< 185 Container, ValueType, boost::optional<Attribute>, Sequence> 186 : pass_through_container_optional< 187 Container, ValueType, Attribute, Sequence> 188 {}; 189 190 // If both, the containers value type and the exposed attribute type are 191 // optionals we are allowed to pass through the the container only if the 192 // embedded types of those optionals are not compatible. 193 template <typename Container, typename ValueType, typename Attribute 194 , typename Sequence> 195 struct pass_through_container< 196 Container, boost::optional<ValueType>, boost::optional<Attribute> 197 , Sequence> 198 : mpl::not_<traits::is_weak_substitute<ValueType, Attribute> > 199 {}; 200 201 // Specialization for exposed variant attributes 202 // 203 // We pass through the container attribute if at least one of the embedded 204 // types in the variant requires to pass through the attribute 205 206#define BOOST_SPIRIT_PASS_THROUGH_CONTAINER(z, N, _) \ 207 pass_through_container<Container, ValueType, \ 208 BOOST_PP_CAT(T, N), Sequence>::type::value || \ 209 /***/ 210 211 // make sure unused variant parameters do not affect the outcome 212 template <typename Container, typename ValueType, typename Sequence> 213 struct pass_through_container<Container, ValueType 214 , boost::detail::variant::void_, Sequence> 215 : mpl::false_ 216 {}; 217 218 template <typename Container, typename ValueType, typename Sequence 219 , BOOST_VARIANT_ENUM_PARAMS(typename T)> 220 struct pass_through_container<Container, ValueType 221 , boost::variant<BOOST_VARIANT_ENUM_PARAMS(T)>, Sequence> 222 : mpl::bool_<BOOST_PP_REPEAT(BOOST_VARIANT_LIMIT_TYPES 223 , BOOST_SPIRIT_PASS_THROUGH_CONTAINER, _) false> 224 {}; 225 226#undef BOOST_SPIRIT_PASS_THROUGH_CONTAINER 227}}}} 228 229/////////////////////////////////////////////////////////////////////////////// 230namespace boost { namespace spirit { namespace traits 231{ 232 /////////////////////////////////////////////////////////////////////////// 233 // forwarding customization point for domain karma::domain 234 template <typename Container, typename ValueType, typename Attribute 235 , typename Sequence> 236 struct pass_through_container< 237 Container, ValueType, Attribute, Sequence, karma::domain> 238 : karma::detail::pass_through_container< 239 Container, ValueType, Attribute, Sequence> 240 {}; 241}}} 242 243namespace boost { namespace spirit { namespace karma { namespace detail 244{ 245 /////////////////////////////////////////////////////////////////////////// 246 // This function handles the case where the attribute (Attr) given 247 // to the sequence is an STL container. This is a wrapper around F. 248 // The function F does the actual generating. 249 template <typename F, typename Attr, typename Iterator, typename Sequence> 250 struct pass_container 251 { 252 typedef typename F::context_type context_type; 253 254 pass_container(F const& f, Iterator begin, Iterator end) 255 : f(f), iter(begin), end(end) 256 {} 257 258 bool is_at_end() const 259 { 260 return traits::compare(iter, end); 261 } 262 263 void next() 264 { 265 traits::next(iter); 266 } 267 268 // this is for the case when the current element expects an attribute 269 // which is taken from the next entry in the container 270 template <typename Component> 271 bool dispatch_container(Component const& component, mpl::false_) const 272 { 273 // get the next value to generate from container 274 if (!is_at_end() && !f(component, traits::deref(iter))) 275 { 276 // needs to return false as long as everything is ok 277 traits::next(iter); 278 return false; 279 } 280 281 // either no elements available any more or generation failed 282 return true; 283 } 284 285 // this is for the case when the current element is able to handle an 286 // attribute which is a container itself, this element will push its 287 // data directly into the attribute container 288 template <typename Component> 289 bool dispatch_container(Component const& component, mpl::true_) const 290 { 291 return f(component, make_iterator_range(iter, end)); 292 } 293 294 /////////////////////////////////////////////////////////////////////// 295 // this is for the case when the current element doesn't expect an 296 // attribute 297 template <typename Component> 298 bool dispatch_attribute(Component const& component, mpl::false_) const 299 { 300 return f(component, unused); 301 } 302 303 // the current element expects an attribute 304 template <typename Component> 305 bool dispatch_attribute(Component const& component, mpl::true_) const 306 { 307 typedef typename traits::container_value<Attr>::type value_type; 308 typedef typename 309 traits::attribute_of<Component, context_type>::type 310 lhs_attribute; 311 312 // this predicate detects, whether the value type of the container 313 // attribute is a substitute for the attribute of the current 314 // element 315 typedef mpl::and_< 316 traits::handles_container<Component, Attr, context_type> 317 , traits::pass_through_container< 318 Attr, value_type, lhs_attribute, Sequence, karma::domain> 319 > predicate; 320 321 return dispatch_container(component, predicate()); 322 } 323 324 // Dispatches to dispatch_main depending on the attribute type 325 // of the Component 326 template <typename Component> 327 bool operator()(Component const& component) const 328 { 329 // we need to dispatch depending on the type of the attribute 330 // of the current element (component). If this is has no attribute 331 // we shouldn't use an element of the container but unused_type 332 // instead 333 typedef traits::not_is_unused< 334 typename traits::attribute_of<Component, context_type>::type 335 > predicate; 336 337 return dispatch_attribute(component, predicate()); 338 } 339 340 F f; 341 mutable Iterator iter; 342 mutable Iterator end; 343 344 private: 345 // silence MSVC warning C4512: assignment operator could not be generated 346 pass_container& operator= (pass_container const&); 347 }; 348}}}} 349 350#endif