// Boost.Function library

//  Copyright Douglas Gregor 2001-2003. Use, modification and
//  distribution is subject to 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)

// For more information, see http://www.boost.org

// Note: this header is a header template and must NOT have multiple-inclusion
// protection.
#include <boost/function/detail/prologue.hpp>

#define BOOST_FUNCTION_TEMPLATE_PARMS BOOST_PP_ENUM_PARAMS(BOOST_FUNCTION_NUM_ARGS, typename T)

#define BOOST_FUNCTION_TEMPLATE_ARGS BOOST_PP_ENUM_PARAMS(BOOST_FUNCTION_NUM_ARGS, T)

#define BOOST_FUNCTION_PARM(J,I,D) BOOST_PP_CAT(T,I) BOOST_PP_CAT(a,I)

#define BOOST_FUNCTION_PARMS BOOST_PP_ENUM(BOOST_FUNCTION_NUM_ARGS,BOOST_FUNCTION_PARM,BOOST_PP_EMPTY)

#define BOOST_FUNCTION_ARGS BOOST_PP_ENUM_PARAMS(BOOST_FUNCTION_NUM_ARGS, a)

#define BOOST_FUNCTION_ARG_TYPE(J,I,D) \
  typedef BOOST_PP_CAT(T,I) BOOST_PP_CAT(BOOST_PP_CAT(arg, BOOST_PP_INC(I)),_type);

#define BOOST_FUNCTION_ARG_TYPES BOOST_PP_REPEAT(BOOST_FUNCTION_NUM_ARGS,BOOST_FUNCTION_ARG_TYPE,BOOST_PP_EMPTY)

// Type of the default allocator
#ifndef BOOST_NO_STD_ALLOCATOR
#  define BOOST_FUNCTION_DEFAULT_ALLOCATOR std::allocator<function_base>
#else
#  define BOOST_FUNCTION_DEFAULT_ALLOCATOR int
#endif // BOOST_NO_STD_ALLOCATOR

// Comma if nonzero number of arguments
#if BOOST_FUNCTION_NUM_ARGS == 0
#  define BOOST_FUNCTION_COMMA
#else
#  define BOOST_FUNCTION_COMMA ,
#endif // BOOST_FUNCTION_NUM_ARGS > 0

// Class names used in this version of the code
#define BOOST_FUNCTION_FUNCTION BOOST_JOIN(function,BOOST_FUNCTION_NUM_ARGS)
#define BOOST_FUNCTION_FUNCTION_INVOKER \
  BOOST_JOIN(function_invoker,BOOST_FUNCTION_NUM_ARGS)
#define BOOST_FUNCTION_VOID_FUNCTION_INVOKER \
  BOOST_JOIN(void_function_invoker,BOOST_FUNCTION_NUM_ARGS)
#define BOOST_FUNCTION_FUNCTION_OBJ_INVOKER \
  BOOST_JOIN(function_obj_invoker,BOOST_FUNCTION_NUM_ARGS)
#define BOOST_FUNCTION_VOID_FUNCTION_OBJ_INVOKER \
  BOOST_JOIN(void_function_obj_invoker,BOOST_FUNCTION_NUM_ARGS)
#define BOOST_FUNCTION_STATELESS_FUNCTION_OBJ_INVOKER \
  BOOST_JOIN(stateless_function_obj_invoker,BOOST_FUNCTION_NUM_ARGS)
#define BOOST_FUNCTION_STATELESS_VOID_FUNCTION_OBJ_INVOKER \
  BOOST_JOIN(stateless_void_function_obj_invoker,BOOST_FUNCTION_NUM_ARGS)
#define BOOST_FUNCTION_GET_FUNCTION_INVOKER \
  BOOST_JOIN(get_function_invoker,BOOST_FUNCTION_NUM_ARGS)
#define BOOST_FUNCTION_GET_FUNCTION_OBJ_INVOKER \
  BOOST_JOIN(get_function_obj_invoker,BOOST_FUNCTION_NUM_ARGS)
#define BOOST_FUNCTION_GET_STATELESS_FUNCTION_OBJ_INVOKER \
  BOOST_JOIN(get_stateless_function_obj_invoker,BOOST_FUNCTION_NUM_ARGS)
#define BOOST_FUNCTION_VTABLE BOOST_JOIN(basic_vtable,BOOST_FUNCTION_NUM_ARGS)

#ifndef BOOST_NO_VOID_RETURNS
#  define BOOST_FUNCTION_VOID_RETURN_TYPE void
#  define BOOST_FUNCTION_RETURN(X) X
#else
#  define BOOST_FUNCTION_VOID_RETURN_TYPE boost::detail::function::unusable
#  define BOOST_FUNCTION_RETURN(X) X; return BOOST_FUNCTION_VOID_RETURN_TYPE ()
#endif

namespace boost {
  namespace detail {
    namespace function {
      template<
        typename FunctionPtr,
        typename R BOOST_FUNCTION_COMMA
        BOOST_FUNCTION_TEMPLATE_PARMS
        >
      struct BOOST_FUNCTION_FUNCTION_INVOKER
      {
        static R invoke(any_pointer function_ptr BOOST_FUNCTION_COMMA
                        BOOST_FUNCTION_PARMS)
        {
          FunctionPtr f = reinterpret_cast<FunctionPtr>(function_ptr.func_ptr);
          return f(BOOST_FUNCTION_ARGS);
        }
      };

      template<
        typename FunctionPtr,
        typename R BOOST_FUNCTION_COMMA
        BOOST_FUNCTION_TEMPLATE_PARMS
        >
      struct BOOST_FUNCTION_VOID_FUNCTION_INVOKER
      {
        static BOOST_FUNCTION_VOID_RETURN_TYPE
        invoke(any_pointer function_ptr BOOST_FUNCTION_COMMA
               BOOST_FUNCTION_PARMS)

        {
          FunctionPtr f = reinterpret_cast<FunctionPtr>(function_ptr.func_ptr);
          BOOST_FUNCTION_RETURN(f(BOOST_FUNCTION_ARGS));
        }
      };

      template<
        typename FunctionObj,
        typename R BOOST_FUNCTION_COMMA
        BOOST_FUNCTION_TEMPLATE_PARMS
      >
      struct BOOST_FUNCTION_FUNCTION_OBJ_INVOKER
      {
        static R invoke(any_pointer function_obj_ptr BOOST_FUNCTION_COMMA
                        BOOST_FUNCTION_PARMS)

        {
          FunctionObj* f = (FunctionObj*)(function_obj_ptr.obj_ptr);
          return (*f)(BOOST_FUNCTION_ARGS);
        }
      };

      template<
        typename FunctionObj,
        typename R BOOST_FUNCTION_COMMA
        BOOST_FUNCTION_TEMPLATE_PARMS
      >
      struct BOOST_FUNCTION_VOID_FUNCTION_OBJ_INVOKER
      {
        static BOOST_FUNCTION_VOID_RETURN_TYPE
        invoke(any_pointer function_obj_ptr BOOST_FUNCTION_COMMA
               BOOST_FUNCTION_PARMS)

        {
          FunctionObj* f = (FunctionObj*)(function_obj_ptr.obj_ptr);
          BOOST_FUNCTION_RETURN((*f)(BOOST_FUNCTION_ARGS));
        }
      };

      template<
        typename FunctionObj,
        typename R BOOST_FUNCTION_COMMA
        BOOST_FUNCTION_TEMPLATE_PARMS
      >
      struct BOOST_FUNCTION_STATELESS_FUNCTION_OBJ_INVOKER
      {
        static R invoke(any_pointer BOOST_FUNCTION_COMMA BOOST_FUNCTION_PARMS)
        {
          FunctionObj f = FunctionObj();
          return f(BOOST_FUNCTION_ARGS);
        }
      };

      template<
        typename FunctionObj,
        typename R BOOST_FUNCTION_COMMA
        BOOST_FUNCTION_TEMPLATE_PARMS
      >
      struct BOOST_FUNCTION_STATELESS_VOID_FUNCTION_OBJ_INVOKER
      {
        static BOOST_FUNCTION_VOID_RETURN_TYPE
        invoke(any_pointer BOOST_FUNCTION_COMMA BOOST_FUNCTION_PARMS)

        {
          FunctionObj f = FunctionObj();
          BOOST_FUNCTION_RETURN(f(BOOST_FUNCTION_ARGS));
        }
      };

      template<
        typename FunctionPtr,
        typename R BOOST_FUNCTION_COMMA
        BOOST_FUNCTION_TEMPLATE_PARMS
      >
      struct BOOST_FUNCTION_GET_FUNCTION_INVOKER
      {
        typedef typename ct_if<(is_void<R>::value),
                            BOOST_FUNCTION_VOID_FUNCTION_INVOKER<
                            FunctionPtr,
                            R BOOST_FUNCTION_COMMA
                            BOOST_FUNCTION_TEMPLATE_ARGS
                          >,
                          BOOST_FUNCTION_FUNCTION_INVOKER<
                            FunctionPtr,
                            R BOOST_FUNCTION_COMMA
                            BOOST_FUNCTION_TEMPLATE_ARGS
                          >
                       >::type type;
      };

      template<
        typename FunctionObj,
        typename R BOOST_FUNCTION_COMMA
        BOOST_FUNCTION_TEMPLATE_PARMS
       >
      struct BOOST_FUNCTION_GET_FUNCTION_OBJ_INVOKER
      {
        typedef typename ct_if<(is_void<R>::value),
                            BOOST_FUNCTION_VOID_FUNCTION_OBJ_INVOKER<
                            FunctionObj,
                            R BOOST_FUNCTION_COMMA
                            BOOST_FUNCTION_TEMPLATE_ARGS
                          >,
                          BOOST_FUNCTION_FUNCTION_OBJ_INVOKER<
                            FunctionObj,
                            R BOOST_FUNCTION_COMMA
                            BOOST_FUNCTION_TEMPLATE_ARGS
                          >
                       >::type type;
      };

      template<
        typename FunctionObj,
        typename R BOOST_FUNCTION_COMMA
        BOOST_FUNCTION_TEMPLATE_PARMS
       >
      struct BOOST_FUNCTION_GET_STATELESS_FUNCTION_OBJ_INVOKER
      {
        typedef typename ct_if<(is_void<R>::value),
                            BOOST_FUNCTION_STATELESS_VOID_FUNCTION_OBJ_INVOKER<
                            FunctionObj,
                            R BOOST_FUNCTION_COMMA
                            BOOST_FUNCTION_TEMPLATE_ARGS
                          >,
                          BOOST_FUNCTION_STATELESS_FUNCTION_OBJ_INVOKER<
                            FunctionObj,
                            R BOOST_FUNCTION_COMMA
                            BOOST_FUNCTION_TEMPLATE_ARGS
                          >
                       >::type type;
      };

      /**
       * vtable for a specific boost::function instance.
       */
      template<typename R BOOST_FUNCTION_COMMA BOOST_FUNCTION_TEMPLATE_PARMS,
               typename Allocator>
      struct BOOST_FUNCTION_VTABLE : vtable_base
      {
#ifndef BOOST_NO_VOID_RETURNS
        typedef R         result_type;
#else
        typedef typename function_return_type<R>::type result_type;
#endif // BOOST_NO_VOID_RETURNS

        typedef result_type (*invoker_type)(any_pointer
                                            BOOST_FUNCTION_COMMA
                                            BOOST_FUNCTION_TEMPLATE_ARGS);

        template<typename F>
        BOOST_FUNCTION_VTABLE(F f) : vtable_base(), invoker(0)
        {
          init(f);
        }

        template<typename F>
        bool assign_to(F f, any_pointer& functor)
        {
          typedef typename get_function_tag<F>::type tag;
          return assign_to(f, functor, tag());
        }

        void clear(any_pointer& functor)
        {
          if (manager)
            functor = manager(functor, destroy_functor_tag);
        }

      private:
        template<typename F>
        void init(F f)
        {
          typedef typename get_function_tag<F>::type tag;
          init(f, tag());
        }

        // Function pointers
        template<typename FunctionPtr>
        void init(FunctionPtr f, function_ptr_tag)
        {
          typedef typename BOOST_FUNCTION_GET_FUNCTION_INVOKER<
                             FunctionPtr,
                             R BOOST_FUNCTION_COMMA
                             BOOST_FUNCTION_TEMPLATE_ARGS
                           >::type
            actual_invoker_type;

          invoker = &actual_invoker_type::invoke;
          manager = &functor_manager<FunctionPtr, Allocator>::manage;
        }

        template<typename FunctionPtr>
        bool assign_to(FunctionPtr f, any_pointer& functor, function_ptr_tag)
        {
          this->clear(functor);
          if (f) {
            // should be a reinterpret cast, but some compilers insist
            // on giving cv-qualifiers to free functions
            functor = manager(make_any_pointer((void (*)())(f)),
                              clone_functor_tag);
            return true;
          } else {
            return false;
          }
        }

        // Member pointers
#if BOOST_FUNCTION_NUM_ARGS > 0
        template<typename MemberPtr>
        void init(MemberPtr f, member_ptr_tag)
        {
          this->init(mem_fn(f));
        }

        template<typename MemberPtr>
        bool assign_to(MemberPtr f, any_pointer& functor, member_ptr_tag)
        {
          if (f) {
            this->assign_to(mem_fn(f), functor);
            return true;
          } else {
            return false;
          }
        }
#endif // BOOST_FUNCTION_NUM_ARGS > 0

        // Stateful function objects
        template<typename FunctionObj>
        void init(FunctionObj f, function_obj_tag)
        {
          typedef typename BOOST_FUNCTION_GET_FUNCTION_OBJ_INVOKER<
                             FunctionObj,
                             R BOOST_FUNCTION_COMMA
                             BOOST_FUNCTION_TEMPLATE_ARGS
                           >::type
            actual_invoker_type;

          invoker = &actual_invoker_type::invoke;
          manager = &functor_manager<FunctionObj, Allocator>::manage;
        }

        template<typename FunctionObj>
        bool assign_to(FunctionObj f, any_pointer& functor, function_obj_tag)
        {
          if (!boost::detail::function::has_empty_target(boost::addressof(f))) {
#ifndef BOOST_NO_STD_ALLOCATOR
            typedef typename Allocator::template rebind<FunctionObj>::other
              rebound_allocator_type;
            typedef typename rebound_allocator_type::pointer pointer_type;
            rebound_allocator_type allocator;
            pointer_type copy = allocator.allocate(1);
            allocator.construct(copy, f);

            // Get back to the original pointer type
            FunctionObj* new_f = static_cast<FunctionObj*>(copy);
#else
            FunctionObj* new_f = new FunctionObj(f);
#endif // BOOST_NO_STD_ALLOCATOR
            functor = make_any_pointer(static_cast<void*>(new_f));
            return true;
          } else {
            return false;
          }
        }

        // Reference to a function object
        template<typename FunctionObj>
        void 
        init(const reference_wrapper<FunctionObj>& f, function_obj_ref_tag)
        {
          typedef typename BOOST_FUNCTION_GET_FUNCTION_OBJ_INVOKER<
                             FunctionObj,
                             R BOOST_FUNCTION_COMMA
                             BOOST_FUNCTION_TEMPLATE_ARGS
                           >::type
            actual_invoker_type;

          invoker = &actual_invoker_type::invoke;
          manager = &trivial_manager<FunctionObj>::get;
        }

        template<typename FunctionObj>
        bool 
        assign_to(const reference_wrapper<FunctionObj>& f, any_pointer& functor,
                  function_obj_ref_tag)
        {
          if (!boost::detail::function::has_empty_target(f.get_pointer())) {
            functor = manager(make_any_pointer(
                                const_cast<FunctionObj*>(f.get_pointer())),
                              clone_functor_tag);
            return true;
          } else {
            return false;
          }
        }

        // Stateless function object
        template<typename FunctionObj>
        void 
        init(FunctionObj, stateless_function_obj_tag)
        {
          typedef
            typename BOOST_FUNCTION_GET_STATELESS_FUNCTION_OBJ_INVOKER<
                       FunctionObj,
                       R BOOST_FUNCTION_COMMA
                       BOOST_FUNCTION_TEMPLATE_ARGS
                     >::type actual_invoker_type;
          invoker = &actual_invoker_type::invoke;
          manager = &trivial_manager<FunctionObj>::get;
        }

        template<typename FunctionObj>
        bool
        assign_to(FunctionObj f, any_pointer& functor, 
                  stateless_function_obj_tag)
        {
          if (!boost::detail::function::has_empty_target(boost::addressof(f))) {
            functor = make_any_pointer(this);
            return true;
          } else {
            return false;
          }
        }

      public:
        invoker_type invoker;
      };
    } // end namespace function
  } // end namespace detail

  template<
    typename R BOOST_FUNCTION_COMMA
    BOOST_FUNCTION_TEMPLATE_PARMS,
    typename Allocator = BOOST_FUNCTION_DEFAULT_ALLOCATOR
  >
  class BOOST_FUNCTION_FUNCTION : public function_base
  {
  public:
#ifndef BOOST_NO_VOID_RETURNS
    typedef R         result_type;
#else
    typedef  typename boost::detail::function::function_return_type<R>::type
      result_type;
#endif // BOOST_NO_VOID_RETURNS

  private:
    typedef boost::detail::function::BOOST_FUNCTION_VTABLE<
              R BOOST_FUNCTION_COMMA BOOST_FUNCTION_TEMPLATE_ARGS, Allocator>
      vtable_type;

    struct clear_type {};

  public:
    BOOST_STATIC_CONSTANT(int, args = BOOST_FUNCTION_NUM_ARGS);

    // add signature for boost::lambda
    template<typename Args>
    struct sig
    {
      typedef result_type type;
    };

#if BOOST_FUNCTION_NUM_ARGS == 1
    typedef T0 argument_type;
#elif BOOST_FUNCTION_NUM_ARGS == 2
    typedef T0 first_argument_type;
    typedef T1 second_argument_type;
#endif

    BOOST_STATIC_CONSTANT(int, arity = BOOST_FUNCTION_NUM_ARGS);
    BOOST_FUNCTION_ARG_TYPES

    typedef Allocator allocator_type;
    typedef BOOST_FUNCTION_FUNCTION self_type;

    BOOST_FUNCTION_FUNCTION() : function_base() { }

    // MSVC chokes if the following two constructors are collapsed into
    // one with a default parameter.
    template<typename Functor>
    BOOST_FUNCTION_FUNCTION(Functor BOOST_FUNCTION_TARGET_FIX(const &) f
#ifndef BOOST_NO_SFINAE
                            ,typename enable_if_c<
                            (boost::type_traits::ice_not<
                             (is_integral<Functor>::value)>::value),
                                        int>::type = 0
#endif // BOOST_NO_SFINAE
                            ) :
      function_base()
    {
      this->assign_to(f);
    }

#ifndef BOOST_NO_SFINAE
    BOOST_FUNCTION_FUNCTION(clear_type*) : function_base() { }
#else
    BOOST_FUNCTION_FUNCTION(int zero) : function_base()
    {
      BOOST_ASSERT(zero == 0);
    }
#endif

    BOOST_FUNCTION_FUNCTION(const BOOST_FUNCTION_FUNCTION& f) : function_base()
    {
      this->assign_to_own(f);
    }

    ~BOOST_FUNCTION_FUNCTION() { clear(); }

#if BOOST_WORKAROUND(BOOST_MSVC, < 1300)
    // MSVC 6.0 and prior require all definitions to be inline, but
    // these definitions can become very costly.
    result_type operator()(BOOST_FUNCTION_PARMS) const
    {
      if (this->empty())
        boost::throw_exception(bad_function_call());

      return static_cast<vtable_type*>(vtable)->invoker
               (this->functor BOOST_FUNCTION_COMMA BOOST_FUNCTION_ARGS);
    }
#else
    result_type operator()(BOOST_FUNCTION_PARMS) const;
#endif

    // The distinction between when to use BOOST_FUNCTION_FUNCTION and
    // when to use self_type is obnoxious. MSVC cannot handle self_type as
    // the return type of these assignment operators, but Borland C++ cannot
    // handle BOOST_FUNCTION_FUNCTION as the type of the temporary to
    // construct.
    template<typename Functor>
#ifndef BOOST_NO_SFINAE
    typename enable_if_c<
               (boost::type_traits::ice_not<
                 (is_integral<Functor>::value)>::value),
               BOOST_FUNCTION_FUNCTION&>::type
#else
    BOOST_FUNCTION_FUNCTION&
#endif
    operator=(Functor BOOST_FUNCTION_TARGET_FIX(const &) f)
    {
      self_type(f).swap(*this);
      return *this;
    }

#ifndef BOOST_NO_SFINAE
    BOOST_FUNCTION_FUNCTION& operator=(clear_type*)
    {
      this->clear();
      return *this;
    }
#else
    BOOST_FUNCTION_FUNCTION& operator=(int zero)
    {
      BOOST_ASSERT(zero == 0);
      this->clear();
      return *this;
    }
#endif

    // Assignment from another BOOST_FUNCTION_FUNCTION
    BOOST_FUNCTION_FUNCTION& operator=(const BOOST_FUNCTION_FUNCTION& f)
    {
      if (&f == this)
        return *this;

      self_type(f).swap(*this);
      return *this;
    }

    void swap(BOOST_FUNCTION_FUNCTION& other)
    {
      if (&other == this)
        return;

      std::swap(this->functor, other.functor);
      std::swap(this->vtable, other.vtable);
    }

    // Clear out a target, if there is one
    void clear()
    {
      if (vtable) {
        static_cast<vtable_type*>(vtable)->clear(this->functor);
        vtable = 0;
      }
    }

#if (defined __SUNPRO_CC) && (__SUNPRO_CC <= 0x530) && !(defined BOOST_NO_COMPILER_CONFIG)
    // Sun C++ 5.3 can't handle the safe_bool idiom, so don't use it
    operator bool () const { return !this->empty(); }
#else
  private:
    struct dummy {
      void nonnull() {};
    };

    typedef void (dummy::*safe_bool)();

  public:
    operator safe_bool () const
      { return (this->empty())? 0 : &dummy::nonnull; }

    bool operator!() const
      { return this->empty(); }
#endif

  private:
    void assign_to_own(const BOOST_FUNCTION_FUNCTION& f)
    {
      if (!f.empty()) {
        this->vtable = f.vtable;
        this->functor =
          f.vtable->manager(f.functor, 
                            boost::detail::function::clone_functor_tag);
      }
    }

    template<typename Functor>
    void assign_to(Functor f)
    {
      static vtable_type stored_vtable(f);
      if (stored_vtable.assign_to(f, functor)) vtable = &stored_vtable;
      else vtable = 0;
    }
  };

  template<typename R BOOST_FUNCTION_COMMA BOOST_FUNCTION_TEMPLATE_PARMS ,
           typename Allocator>
  inline void swap(BOOST_FUNCTION_FUNCTION<
                     R BOOST_FUNCTION_COMMA
                     BOOST_FUNCTION_TEMPLATE_ARGS ,
                     Allocator
                   >& f1,
                   BOOST_FUNCTION_FUNCTION<
                     R BOOST_FUNCTION_COMMA
                     BOOST_FUNCTION_TEMPLATE_ARGS,
                     Allocator
                   >& f2)
  {
    f1.swap(f2);
  }

#if !BOOST_WORKAROUND(BOOST_MSVC, < 1300)
  template<typename R BOOST_FUNCTION_COMMA BOOST_FUNCTION_TEMPLATE_PARMS,
           typename Allocator>
  typename BOOST_FUNCTION_FUNCTION<
      R BOOST_FUNCTION_COMMA BOOST_FUNCTION_TEMPLATE_ARGS,
      Allocator>::result_type
   BOOST_FUNCTION_FUNCTION<R BOOST_FUNCTION_COMMA BOOST_FUNCTION_TEMPLATE_ARGS,

                           Allocator>
  ::operator()(BOOST_FUNCTION_PARMS) const
  {
    if (this->empty())
      boost::throw_exception(bad_function_call());

    return static_cast<vtable_type*>(vtable)->invoker
             (this->functor BOOST_FUNCTION_COMMA BOOST_FUNCTION_ARGS);
  }
#endif

// Poison comparisons between boost::function objects of the same type.
template<typename R BOOST_FUNCTION_COMMA BOOST_FUNCTION_TEMPLATE_PARMS ,
         typename Allocator>
  void operator==(const BOOST_FUNCTION_FUNCTION<
                          R BOOST_FUNCTION_COMMA
                          BOOST_FUNCTION_TEMPLATE_ARGS ,
                          Allocator>&,
                  const BOOST_FUNCTION_FUNCTION<
                          R BOOST_FUNCTION_COMMA
                          BOOST_FUNCTION_TEMPLATE_ARGS ,
                  Allocator>&);
template<typename R BOOST_FUNCTION_COMMA BOOST_FUNCTION_TEMPLATE_PARMS ,
         typename Allocator>
  void operator!=(const BOOST_FUNCTION_FUNCTION<
                          R BOOST_FUNCTION_COMMA
                          BOOST_FUNCTION_TEMPLATE_ARGS ,
                          Allocator>&,
                  const BOOST_FUNCTION_FUNCTION<
                          R BOOST_FUNCTION_COMMA
                          BOOST_FUNCTION_TEMPLATE_ARGS ,
                  Allocator>&);

#if !defined(BOOST_FUNCTION_NO_FUNCTION_TYPE_SYNTAX)

#if BOOST_FUNCTION_NUM_ARGS == 0
#define BOOST_FUNCTION_PARTIAL_SPEC R (void)
#else
#define BOOST_FUNCTION_PARTIAL_SPEC R (BOOST_PP_ENUM_PARAMS(BOOST_FUNCTION_NUM_ARGS,T))
#endif

template<typename R BOOST_FUNCTION_COMMA
         BOOST_FUNCTION_TEMPLATE_PARMS,
         typename Allocator>
class function<BOOST_FUNCTION_PARTIAL_SPEC, Allocator>
  : public BOOST_FUNCTION_FUNCTION<R, BOOST_FUNCTION_TEMPLATE_ARGS
                                   BOOST_FUNCTION_COMMA Allocator>
{
  typedef BOOST_FUNCTION_FUNCTION<R, BOOST_FUNCTION_TEMPLATE_ARGS
                                  BOOST_FUNCTION_COMMA Allocator> base_type;
  typedef function self_type;

  struct clear_type {};

public:
  typedef typename base_type::allocator_type allocator_type;

  function() : base_type() {}

  template<typename Functor>
  function(Functor f
#ifndef BOOST_NO_SFINAE
           ,typename enable_if_c<
                            (boost::type_traits::ice_not<
                          (is_integral<Functor>::value)>::value),
                       int>::type = 0
#endif
           ) :
    base_type(f)
  {
  }

#ifndef BOOST_NO_SFINAE
  function(clear_type*) : base_type() {}
#endif

  function(const self_type& f) : base_type(static_cast<const base_type&>(f)){}

  function(const base_type& f) : base_type(static_cast<const base_type&>(f)){}

  self_type& operator=(const self_type& f)
  {
    self_type(f).swap(*this);
    return *this;
  }

  template<typename Functor>
#ifndef BOOST_NO_SFINAE
  typename enable_if_c<
                            (boost::type_traits::ice_not<
                         (is_integral<Functor>::value)>::value),
                      self_type&>::type
#else
  self_type&
#endif
  operator=(Functor f)
  {
    self_type(f).swap(*this);
    return *this;
  }

#ifndef BOOST_NO_SFINAE
  self_type& operator=(clear_type*)
  {
    this->clear();
    return *this;
  }
#endif

  self_type& operator=(const base_type& f)
  {
    self_type(f).swap(*this);
    return *this;
  }
};

#undef BOOST_FUNCTION_PARTIAL_SPEC
#endif // have partial specialization

} // end namespace boost

// Cleanup after ourselves...
#undef BOOST_FUNCTION_VTABLE
#undef BOOST_FUNCTION_DEFAULT_ALLOCATOR
#undef BOOST_FUNCTION_COMMA
#undef BOOST_FUNCTION_FUNCTION
#undef BOOST_FUNCTION_FUNCTION_INVOKER
#undef BOOST_FUNCTION_VOID_FUNCTION_INVOKER
#undef BOOST_FUNCTION_FUNCTION_OBJ_INVOKER
#undef BOOST_FUNCTION_VOID_FUNCTION_OBJ_INVOKER
#undef BOOST_FUNCTION_STATELESS_FUNCTION_OBJ_INVOKER
#undef BOOST_FUNCTION_STATELESS_VOID_FUNCTION_OBJ_INVOKER
#undef BOOST_FUNCTION_GET_FUNCTION_INVOKER
#undef BOOST_FUNCTION_GET_FUNCTION_OBJ_INVOKER
#undef BOOST_FUNCTION_GET_STATELESS_FUNCTION_OBJ_INVOKER
#undef BOOST_FUNCTION_GET_MEM_FUNCTION_INVOKER
#undef BOOST_FUNCTION_TEMPLATE_PARMS
#undef BOOST_FUNCTION_TEMPLATE_ARGS
#undef BOOST_FUNCTION_PARMS
#undef BOOST_FUNCTION_PARM
#undef BOOST_FUNCTION_ARGS
#undef BOOST_FUNCTION_ARG_TYPE
#undef BOOST_FUNCTION_ARG_TYPES
#undef BOOST_FUNCTION_VOID_RETURN_TYPE
#undef BOOST_FUNCTION_RETURN