Squashed 'third_party/boostorg/concept_check/' content from commit ed0a0eb

Change-Id: Ib7230965334f9501601efc300242efde8352a380
git-subtree-dir: third_party/boostorg/concept_check
git-subtree-split: ed0a0ebd72f778cfa4931e0538ea34c28db3a42b
diff --git a/include/boost/concept_check/general.hpp b/include/boost/concept_check/general.hpp
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+// Copyright David Abrahams 2006. Distributed under the Boost
+// Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+#ifndef BOOST_CONCEPT_CHECK_MSVC_DWA2006429_HPP
+# define BOOST_CONCEPT_CHECK_MSVC_DWA2006429_HPP
+
+# ifdef BOOST_OLD_CONCEPT_SUPPORT
+#  include <boost/concept_check/has_constraints.hpp>
+#  include <boost/mpl/if.hpp>
+# endif
+
+
+// This implementation works on GCC and Comeau, but has actually been
+// fairly carefully tuned to work on GCC versions starting with
+// gcc-2.95.x.  If you're trying to get an additional compiler to pass
+// the tests you might consider breaking out a separate gcc.hpp and
+// starting over on the general case.
+namespace boost
+{
+  namespace concept_checking
+  {
+    template <void(*)()> struct instantiate {};
+  }
+  
+  template <class ModelFn> struct concept_check_;
+
+  template <class Model>
+  void concept_check_failed()
+  {
+      ((Model*)0)->~Model();
+  }
+
+  template <class Model>
+  struct concept_check
+  {
+      concept_checking::instantiate<concept_check_failed<Model> > x;
+      enum { instantiate = 1 };
+  };
+
+# ifdef BOOST_OLD_CONCEPT_SUPPORT
+  
+  template <class Model>
+  void constraint_check_failed()
+  {
+      ((Model*)0)->constraints();
+  }
+
+  template <class Model>
+  struct constraint_check
+  {
+      concept_checking::instantiate<constraint_check_failed<Model> > x;
+      enum { instantiate = 1 };
+  };
+  
+  template <class Model>
+  struct concept_check_<void(*)(Model)>
+    : mpl::if_c<
+          concept_checking::has_constraints<Model>::value
+        , constraint_check<Model>
+        , concept_check<Model>
+      >::type
+  {};
+  
+# else
+  
+  template <class Model>
+  struct concept_check_<void(*)(Model)>
+    : concept_check<Model>
+  {};
+  
+# endif
+  
+  // Usage, in class or function context:
+  //
+  //     BOOST_CONCEPT_ASSERT((UnaryFunctionConcept<F,bool,int>));
+#  define BOOST_CONCEPT_ASSERT( ModelInParens )                             \
+  enum { BOOST_PP_CAT(boost_concept_check,__LINE__) =                       \
+         ::boost::concept_check_<void(*) ModelInParens>::instantiate        \
+  }
+}
+
+#endif // BOOST_CONCEPT_CHECK_MSVC_DWA2006429_HPP