[Boost-commit] svn:boost r63322 - sandbox/variadic_templates/boost/function_types

Subject: [Boost-commit] svn:boost r63322 - sandbox/variadic_templates/boost/function_types
From: cppljevans_at_[hidden]
Date: 2010-06-25 15:07:54

Author: cppljevans
Date: 2010-06-25 15:07:53 EDT (Fri, 25 Jun 2010)
New Revision: 63322
URL: http://svn.boost.org/trac/boost/changeset/63322

Log:
needed by composite_storage/pack/multiple_dispatch/apply_unpack.hpp
Added:
   sandbox/variadic_templates/boost/function_types/
   sandbox/variadic_templates/boost/function_types/can_be_called.hpp   (contents, props changed)

Added: sandbox/variadic_templates/boost/function_types/can_be_called.hpp
==============================================================================
--- (empty file)
+++ sandbox/variadic_templates/boost/function_types/can_be_called.hpp	2010-06-25 15:07:53 EDT (Fri, 25 Jun 2010)
@@ -0,0 +1,163 @@
+#ifndef BOOST_FT_CAN_BE_CALLED_HPP_INCLUDED
+#define BOOST_FT_CAN_BE_CALLED_HPP_INCLUDED
+//  (C) Copyright Larry Evans 2010.
+//
+//  Permission to copy, use, modify, sell and distribute this software
+//  is granted provided this copyright notice appears in all copies.
+//  This software is provided "as is" without express or implied
+//  warranty, and with no claim as to its suitability for any purpose.
+//====================================================================
+#include <boost/mpl/package_range_c.hpp>
+
+namespace boost
+{
+namespace function_types
+{
+//Acknowledgments:
+//  The code in this part of this namespace is basicly that posted here:
+//    http://article.gmane.org/gmane.comp.lib.boost.devel/203956
+//  with headers:
+/*
+From: Larry Evans <cppljevans <at> suddenlink.net>
+Subject: Re: [proto][can_be_called]
+Newsgroups: gmane.comp.lib.boost.devel
+Date: 2010-05-08 18:26:38 GMT
+ */
+//
+namespace detail_can_be_called
+{
+struct dont_care
+{
+    dont_care(...);
+};
+
+struct private_type
+{
+    private_type const &operator,(int) const;
+};
+
+typedef char yes_type;      // sizeof(yes_type) == 1
+typedef char (&no_type)[2]; // sizeof(no_type)  == 2
+
+template<typename T>
+no_type is_private_type(T const &);
+
+yes_type is_private_type(private_type const &);
+
+template<typename Value, typename Indices>
+struct repeat_indices
+;
+template<typename Value, unsigned... Indices>
+struct repeat_indices<Value, boost::mpl::package_c<unsigned, Indices...> >
+{
+      template
+      < unsigned IndexValue
+      >
+    struct always_value
+    {
+        typedef Value type;
+    };
+        typedef 
+      boost::mpl::package
+      < typename always_value<Indices>::type...
+      >
+    type
+    ;
+};
+template<typename Value, unsigned N>
+struct repeat
+/**@brief
+ *  Create package<typename... Values>
+ *  with size=N and Values... are all Value.
+ */
+: repeat_indices<Value,typename boost::mpl::package_range_c<unsigned,0,N>::type>
+{
+};
+
+template<typename Fun, typename DontCares>
+struct funwrap_dont_care
+;
+template<typename Fun, typename... DontCares>
+struct funwrap_dont_care<Fun, boost::mpl::package<DontCares...> >
+: Fun
+{
+    funwrap_dont_care();
+    typedef private_type const &(*pointer_to_function)(DontCares...);
+    operator pointer_to_function() const;
+};
+
+template<typename Fun, typename Indices, typename... Args>
+struct can_be_called_impl
+;
+template<typename Fun, unsigned... Indices, typename... Args>
+struct can_be_called_impl<Fun, boost::mpl::package_c<unsigned, Indices...>, Args...>
+{
+ private:
+    static unsigned const arity=sizeof...(Args);
+    static funwrap_dont_care<Fun, typename repeat<dont_care,arity>::type> &fun;
+      template
+      < unsigned IndexValue
+      >
+        static
+      typename mpl::arg
+        < IndexValue
+        + 1 //because mpl::arg<1> retrieves 1st index.
+        >
+      ::template apply<Args...>::type
+    at_value(void)
+      /**@brief
+       *  Never used at runtime.  Only used to calculate value below.
+       */
+    ;
+    static bool const value = 
+    (
+        sizeof(no_type) == 
+        sizeof
+        ( is_private_type
+          ( ( fun 
+              ( at_value<Indices>()...
+              )
+            , 0
+            ) 
+          )
+        )
+    );
+ public:
+    typedef boost::mpl::bool_<value> type;
+};
+
+}//exit detail_can_be_called
+
+template<typename Sig>
+struct can_be_called
+;
+template<typename Fun, typename... Args>
+struct can_be_called<Fun(Args...)>
+: detail_can_be_called::can_be_called_impl
+  < Fun
+  , typename boost::mpl::package_range_c
+    < unsigned
+    , 0
+    , sizeof...(Args)
+    >::type
+  , Args...
+  >
+{
+};
+template<typename Fun, typename... Args>
+struct can_be_called<Fun const(Args...)>
+: detail_can_be_called::can_be_called_impl
+  < Fun const
+  , typename boost::mpl::package_range_c
+    < unsigned
+    , 0
+    , sizeof...(Args)
+    >::type
+  , Args...
+  >
+{
+};
+
+}//exit function_types namespace
+}//exit boost namespace
+#endif