ceph/src/boost/libs/concept_check/include/boost/concept/requires.hpp

   1 // Copyright David Abrahams 2006. Distributed under the Boost
   2 // Software License, Version 1.0. (See accompanying
   3 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   4 #ifndef BOOST_CONCEPT_REQUIRES_DWA2006430_HPP
   5 # define BOOST_CONCEPT_REQUIRES_DWA2006430_HPP
   6
   7 # include <boost/config.hpp>
   8 # include <boost/concept/assert.hpp>
   9 # include <boost/preprocessor/seq/for_each.hpp>
  10
  11 namespace boost {
  12
  13 // unaryfunptr_arg_type from parameter/aux_/parenthesized_type.hpp
  14
  15 namespace ccheck_aux {
  16
  17 // A metafunction that transforms void(*)(T) -> T
  18 template <class UnaryFunctionPointer>
  19 struct unaryfunptr_arg_type;
  20
  21 template <class Arg>
  22 struct unaryfunptr_arg_type<void(*)(Arg)>
  23 {
  24     typedef Arg type;
  25 };
  26
  27 template <>
  28 struct unaryfunptr_arg_type<void(*)(void)>
  29 {
  30     typedef void type;
  31 };
  32
  33 } // namespace ccheck_aux
  34
  35 // Template for use in handwritten assertions
  36 template <class Model, class More>
  37 struct requires_ : More
  38 {
  39     BOOST_CONCEPT_ASSERT((Model));
  40 };
  41
  42 // Template for use by macros, where models must be wrapped in parens.
  43 // This isn't in namespace detail to keep extra cruft out of resulting
  44 // error messages.
  45 template <class ModelFn>
  46 struct _requires_
  47 {
  48     enum { value = 0 };
  49     BOOST_CONCEPT_ASSERT_FN(ModelFn);
  50 };
  51
  52 template <int check, class Result>
  53 struct Requires_ : ::boost::ccheck_aux::unaryfunptr_arg_type<Result>
  54 {
  55 };
  56
  57 # if BOOST_WORKAROUND(BOOST_INTEL_WIN, BOOST_TESTED_AT(1010))
  58 #  define BOOST_CONCEPT_REQUIRES_(r,data,t) | (::boost::_requires_<void(*)t>::value)
  59 # else
  60 #  define BOOST_CONCEPT_REQUIRES_(r,data,t) + (::boost::_requires_<void(*)t>::value)
  61 # endif
  62
  63 #if defined(NDEBUG)
  64
  65 # define BOOST_CONCEPT_REQUIRES(models, result)                                    \
  66     typename ::boost::ccheck_aux::unaryfunptr_arg_type<void(*)result>::type
  67
  68 #elif BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT(0x564))
  69
  70 // Same thing as below without the initial typename
  71 # define BOOST_CONCEPT_REQUIRES(models, result)                                \
  72     ::boost::Requires_<                                                        \
  73       (0 BOOST_PP_SEQ_FOR_EACH(BOOST_CONCEPT_REQUIRES_, ~, models)),           \
  74       ::boost::ccheck_aux::unaryfunptr_arg_type<void(*)result>          \
  75                      >::type
  76
  77 #else
  78
  79 // This just ICEs on MSVC6 :(
  80 # define BOOST_CONCEPT_REQUIRES(models, result)                                        \
  81     typename ::boost::Requires_<                                                       \
  82       (0 BOOST_PP_SEQ_FOR_EACH(BOOST_CONCEPT_REQUIRES_, ~, models)),                   \
  83       void(*)result                                                                 \
  84     >::type
  85
  86 #endif
  87
  88 // C++0x proposed syntax changed.  This supports an older usage
  89 #define BOOST_CONCEPT_WHERE(models,result) BOOST_CONCEPT_REQUIRES(models,result)
  90
  91 } // namespace boost::concept_check
  92
  93 #endif // BOOST_CONCEPT_REQUIRES_DWA2006430_HPP