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 // Boost.Function library
 
-// Copyright (C) 2001 Doug Gregor (gregod@cs.rpi.edu)
-//
-// Permission to copy, use, sell and distribute this software is granted
-// provided this copyright notice appears in all copies.
-// Permission to modify the code and to distribute modified code is granted
-// provided this copyright notice appears in all copies, and a notice
-// that the code was modified is included with the copyright notice.
-//
-// This software is provided "as is" without express or implied warranty,
-// and with no claim as to its suitability for any purpose.
+//  Copyright Douglas Gregor 2001-2006. 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
 
 #ifndef BOOST_FUNCTION_BASE_HEADER
 #define BOOST_FUNCTION_BASE_HEADER
 
-#include <string>
 #include <stdexcept>
+#include <string>
 #include <memory>
 #include <new>
 #include <typeinfo>
 #include <boost/config.hpp>
-#include <boost/type_traits.hpp>
+#include <boost/assert.hpp>
+#include <boost/type_traits/is_integral.hpp>
+#include <boost/type_traits/composite_traits.hpp>
 #include <boost/ref.hpp>
-#include <boost/pending/ct_if.hpp>
+#include <boost/mpl/if.hpp>
+#include <boost/detail/workaround.hpp>
+#include <boost/type_traits/alignment_of.hpp>
+#ifndef BOOST_NO_SFINAE
+#  include "boost/utility/enable_if.hpp"
+#else
+#  include "boost/mpl/bool.hpp"
+#endif
+#include <boost/function_equal.hpp>
+
+// Borrowed from Boost.Python library: determines the cases where we
+// need to use std::type_info::name to compare instead of operator==.
+# if (defined(__GNUC__) && __GNUC__ >= 3) \
+ || defined(_AIX) \
+ || (   defined(__sgi) && defined(__host_mips))
+#  include <cstring>
+#  define BOOST_FUNCTION_COMPARE_TYPE_ID(X,Y) \
+     (std::strcmp((X).name(),(Y).name()) == 0)
+# else
+#  define BOOST_FUNCTION_COMPARE_TYPE_ID(X,Y) ((X)==(Y))
+#endif
 
-#if defined(BOOST_MSVC) && BOOST_MSVC <= 1300 || defined(__ICL) && __ICL <= 600 || defined(__MWERKS__) && __MWERKS__ < 0x2406
+#if defined(BOOST_MSVC) && BOOST_MSVC <= 1300 || defined(__ICL) && __ICL <= 600 || defined(__MWERKS__) && __MWERKS__ < 0x2406 && !defined(BOOST_STRICT_CONFIG)
 #  define BOOST_FUNCTION_TARGET_FIX(x) x
 #else
 #  define BOOST_FUNCTION_TARGET_FIX(x)
 #endif // not MSVC
 
-#if defined (BOOST_MSVC) && (BOOST_MSVC >= 1300)
-#  define BOOST_FUNCTION_DEPRECATED_PRE __declspec(deprecated)
-#  define BOOST_FUNCTION_DEPRECATED_INNER
+#if defined(__sgi) && defined(_COMPILER_VERSION) && _COMPILER_VERSION <= 730 && !defined(BOOST_STRICT_CONFIG)
+// Work around a compiler bug.
+// boost::python::objects::function has to be seen by the compiler before the
+// boost::function class template.
+namespace boost { namespace python { namespace objects {
+  class function;
+}}}
+#endif
+
+#if defined (BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION)                    \
+ || defined(BOOST_BCB_PARTIAL_SPECIALIZATION_BUG)                         \
+ || !(BOOST_STRICT_CONFIG || !defined(__SUNPRO_CC) || __SUNPRO_CC > 0x540)
+#  define BOOST_FUNCTION_NO_FUNCTION_TYPE_SYNTAX
+#endif
+
+#if !BOOST_WORKAROUND(__BORLANDC__, < 0x600)
+#  define BOOST_FUNCTION_ENABLE_IF_NOT_INTEGRAL(Functor,Type)              \
+      typename ::boost::enable_if_c<(::boost::type_traits::ice_not<          \
+                            (::boost::is_integral<Functor>::value)>::value), \
+                           Type>::type
+#else
+// BCC doesn't recognize this depends on a template argument and complains
+// about the use of 'typename'
+#  define BOOST_FUNCTION_ENABLE_IF_NOT_INTEGRAL(Functor,Type)     \
+      ::boost::enable_if_c<(::boost::type_traits::ice_not<          \
+                   (::boost::is_integral<Functor>::value)>::value), \
+                       Type>::type
+#endif
+
+#if !defined(BOOST_FUNCTION_NO_FUNCTION_TYPE_SYNTAX)
+namespace boost {
+
+#if defined(__sgi) && defined(_COMPILER_VERSION) && _COMPILER_VERSION <= 730 && !defined(BOOST_STRICT_CONFIG)
+// The library shipping with MIPSpro 7.3.1.3m has a broken allocator<void>
+class function_base;
+
+template<typename Signature,
+         typename Allocator = std::allocator<function_base> >
+class function;
 #else
-#  define BOOST_FUNCTION_DEPRECATED_PRE
-#  define BOOST_FUNCTION_DEPRECATED_INNER int deprecated;
+template<typename Signature, typename Allocator = std::allocator<void> >
+class function;
 #endif
 
+template<typename Signature, typename Allocator>
+inline void swap(function<Signature, Allocator>& f1,
+                 function<Signature, Allocator>& f2)
+{
+  f1.swap(f2);
+}
+
+} // end namespace boost
+#endif // have partial specialization
+
 namespace boost {
   namespace detail {
     namespace function {
+      class X;
+
       /**
-       * A union of a function pointer and a void pointer. This is necessary
-       * because 5.2.10/6 allows reinterpret_cast<> to safely cast between
-       * function pointer types and 5.2.9/10 allows static_cast<> to safely
-       * cast between a void pointer and an object pointer. But it is not legal
-       * to cast between a function pointer and a void* (in either direction),
-       * so function requires a union of the two. */
-      union any_pointer
+       * A buffer used to store small function objects in
+       * boost::function. It is a union containing function pointers,
+       * object pointers, and a structure that resembles a bound
+       * member function pointer.
+       */
+      union function_buffer
       {
-       void* obj_ptr;
-       const void* const_obj_ptr;
-       void (*func_ptr)();
+        // For pointers to function objects
+        void* obj_ptr;
+
+        // For pointers to std::type_info objects
+        // (get_functor_type_tag, check_functor_type_tag).
+        const void* const_obj_ptr;
 
-       explicit any_pointer(void* p) : obj_ptr(p) {}
-       explicit any_pointer(const void* p) : const_obj_ptr(p) {}
-       explicit any_pointer(void (*p)()) : func_ptr(p) {}
+        // For function pointers of all kinds
+        mutable void (*func_ptr)();
+
+        // For bound member pointers
+        struct bound_memfunc_ptr_t {
+          void (X::*memfunc_ptr)(int);
+          void* obj_ptr;
+        } bound_memfunc_ptr;
+
+        // To relax aliasing constraints
+        mutable char data;
       };
 
       /**
@@ -69,8 +143,8 @@ namespace boost {
        */
       struct unusable
       {
-       unusable() {}
-       template<typename T> unusable(const T&) {}
+        unusable() {}
+        template<typename T> unusable(const T&) {}
       };
 
       /* Determine the return type. This supports compilers that do not support
@@ -82,13 +156,15 @@ namespace boost {
       template<>
       struct function_return_type<void>
       {
-       typedef unusable type;
+        typedef unusable type;
       };
 
       // The operation type to perform on the given functor/function pointer
       enum functor_manager_operation_type {
-       clone_functor_tag,
-       destroy_functor_tag
+        clone_functor_tag,
+        destroy_functor_tag,
+        check_functor_type_tag,
+        get_functor_type_tag
       };
 
       // Tags used to decide between different types of functions
@@ -96,39 +172,78 @@ namespace boost {
       struct function_obj_tag {};
       struct member_ptr_tag {};
       struct function_obj_ref_tag {};
-      struct stateless_function_obj_tag {};
 
       template<typename F>
       class get_function_tag
       {
-       typedef typename ct_if<(is_pointer<F>::value),
-                           function_ptr_tag,
-                           function_obj_tag>::type ptr_or_obj_tag;
+        typedef typename mpl::if_c<(is_pointer<F>::value),
+                                   function_ptr_tag,
+                                   function_obj_tag>::type ptr_or_obj_tag;
 
-       typedef typename ct_if<(is_member_pointer<F>::value),
-                           member_ptr_tag,
-                           ptr_or_obj_tag>::type ptr_or_obj_or_mem_tag;
+        typedef typename mpl::if_c<(is_member_pointer<F>::value),
+                                   member_ptr_tag,
+                                   ptr_or_obj_tag>::type ptr_or_obj_or_mem_tag;
 
-       typedef typename ct_if<(is_reference_wrapper<F>::value),
-                            function_obj_ref_tag,
-                            ptr_or_obj_or_mem_tag>::type or_ref_tag;
+        typedef typename mpl::if_c<(is_reference_wrapper<F>::value),
+                                   function_obj_ref_tag,
+                                   ptr_or_obj_or_mem_tag>::type or_ref_tag;
 
       public:
-       typedef typename ct_if<(is_stateless<F>::value),
-                           stateless_function_obj_tag,
-                           or_ref_tag>::type type;
+        typedef or_ref_tag type;
       };
 
       // The trivial manager does nothing but return the same pointer (if we
       // are cloning) or return the null pointer (if we are deleting).
-      inline any_pointer trivial_manager(any_pointer f,
-                                        functor_manager_operation_type op)
+      template<typename F>
+      struct reference_manager
       {
-       if (op == clone_functor_tag)
-         return f;
-       else
-         return any_pointer(reinterpret_cast<void*>(0));
-      }
+        static inline void
+        get(const function_buffer& in_buffer, function_buffer& out_buffer, 
+            functor_manager_operation_type op)
+        {
+          switch (op) {
+          case clone_functor_tag: 
+            out_buffer.obj_ptr = in_buffer.obj_ptr;
+            return;
+
+          case destroy_functor_tag:
+            out_buffer.obj_ptr = 0;
+            return;
+
+          case check_functor_type_tag:
+            {
+              // DPG TBD: Since we're only storing a pointer, it's
+              // possible that the user could ask for a base class or
+              // derived class. Is that okay?
+              const std::type_info& check_type = 
+                *static_cast<const std::type_info*>(out_buffer.const_obj_ptr);
+              if (BOOST_FUNCTION_COMPARE_TYPE_ID(check_type, typeid(F)))
+                out_buffer.obj_ptr = in_buffer.obj_ptr;
+              else
+                out_buffer.obj_ptr = 0;
+            }
+            return;
+
+          case get_functor_type_tag:
+            out_buffer.const_obj_ptr = &typeid(F);
+            return;
+          }
+        }
+      };
+
+      /**
+       * Determine if boost::function can use the small-object
+       * optimization with the function object type F.
+       */
+      template<typename F>
+      struct function_allows_small_object_optimization
+      {
+        BOOST_STATIC_CONSTANT
+          (bool, 
+           value = ((sizeof(F) <= sizeof(function_buffer) &&
+                     (alignment_of<function_buffer>::value 
+                      % alignment_of<F>::value == 0))));
+      };
 
       /**
        * The functor_manager class contains a static function "manage" which
@@ -138,205 +253,486 @@ namespace boost {
       struct functor_manager
       {
       private:
-       typedef Functor functor_type;
-
-       // For function pointers, the manager is trivial
-       static inline any_pointer
-       manager(any_pointer function_ptr,
-               functor_manager_operation_type op,
-               function_ptr_tag)
-       {
-         if (op == clone_functor_tag)
-           return function_ptr;
-         else
-           return any_pointer(static_cast<void (*)()>(0));
-       }
-
-       // For function object pointers, we clone the pointer to each
-       // function has its own version.
-       static inline any_pointer
-       manager(any_pointer function_obj_ptr,
-               functor_manager_operation_type op,
-               function_obj_tag)
-       {
+        typedef Functor functor_type;
+
+        // For function pointers, the manager is trivial
+        static inline void
+        manager(const function_buffer& in_buffer, function_buffer& out_buffer, 
+                functor_manager_operation_type op, function_ptr_tag)
+        {
+          if (op == clone_functor_tag)
+            out_buffer.func_ptr = in_buffer.func_ptr;
+          else if (op == destroy_functor_tag)
+            out_buffer.func_ptr = 0;
+          else /* op == check_functor_type_tag */ {
+            const std::type_info& check_type = 
+              *static_cast<const std::type_info*>(out_buffer.const_obj_ptr);
+            if (BOOST_FUNCTION_COMPARE_TYPE_ID(check_type, typeid(Functor)))
+              out_buffer.obj_ptr = &in_buffer.func_ptr;
+            else
+              out_buffer.obj_ptr = 0;
+          }
+        }
+
+        // Function objects that fit in the small-object buffer.
+        static inline void
+        manager(const function_buffer& in_buffer, function_buffer& out_buffer, 
+                functor_manager_operation_type op, mpl::true_)
+        {
+          if (op == clone_functor_tag) {
+            const functor_type* in_functor = 
+              reinterpret_cast<const functor_type*>(&in_buffer.data);
+            new ((void*)&out_buffer.data) functor_type(*in_functor);
+          } else if (op == destroy_functor_tag) {
+            functor_type* out_functor = 
+              reinterpret_cast<functor_type*>(&out_buffer.data);
+            // Some compilers (Borland, vc6, ...) are unhappy with ~functor_type.
+            out_functor->~Functor();
+          } else /* op == check_functor_type_tag */ {
+            const std::type_info& check_type = 
+              *static_cast<const std::type_info*>(out_buffer.const_obj_ptr);
+            if (BOOST_FUNCTION_COMPARE_TYPE_ID(check_type, typeid(Functor)))
+              out_buffer.obj_ptr = &in_buffer.data;
+            else
+              out_buffer.obj_ptr = 0;
+          }
+        }
+        
+        // Function objects that require heap allocation
+        static inline void
+        manager(const function_buffer& in_buffer, function_buffer& out_buffer, 
+                functor_manager_operation_type op, mpl::false_)
+        {
 #ifndef BOOST_NO_STD_ALLOCATOR
-       typedef typename Allocator::template rebind<functor_type>::other
-         allocator_type;
-       typedef typename allocator_type::pointer pointer_type;
+          typedef typename Allocator::template rebind<functor_type>::other
+            allocator_type;
+          typedef typename allocator_type::pointer pointer_type;
 #else
-       typedef functor_type* pointer_type;
+          typedef functor_type* pointer_type;
 #endif // BOOST_NO_STD_ALLOCATOR
 
 #  ifndef BOOST_NO_STD_ALLOCATOR
-         allocator_type allocator;
+          allocator_type allocator;
 #  endif // BOOST_NO_STD_ALLOCATOR
 
-         if (op == clone_functor_tag) {
-           functor_type* f =
-             static_cast<functor_type*>(function_obj_ptr.obj_ptr);
+          if (op == clone_functor_tag) {
+            // GCC 2.95.3 gets the CV qualifiers wrong here, so we
+            // can't do the static_cast that we should do.
+            const functor_type* f =
+              (const functor_type*)(in_buffer.obj_ptr);
 
-           // Clone the functor
+            // Clone the functor
 #  ifndef BOOST_NO_STD_ALLOCATOR
-           pointer_type copy = allocator.allocate(1);
-           allocator.construct(copy, *f);
+            pointer_type copy = allocator.allocate(1);
+            allocator.construct(copy, *f);
 
-           // Get back to the original pointer type
-           functor_type* new_f = static_cast<functor_type*>(copy);
+            // Get back to the original pointer type
+            functor_type* new_f = static_cast<functor_type*>(copy);
 #  else
-           functor_type* new_f = new functor_type(*f);
+            functor_type* new_f = new functor_type(*f);
 #  endif // BOOST_NO_STD_ALLOCATOR
-           return any_pointer(static_cast<void*>(new_f));
-         }
-         else {
-           /* Cast from the void pointer to the functor pointer type */
-           functor_type* f =
-             reinterpret_cast<functor_type*>(function_obj_ptr.obj_ptr);
+            out_buffer.obj_ptr = new_f;
+          } else if (op == destroy_functor_tag) {
+            /* Cast from the void pointer to the functor pointer type */
+            functor_type* f =
+              static_cast<functor_type*>(out_buffer.obj_ptr);
 
 #  ifndef BOOST_NO_STD_ALLOCATOR
-           /* Cast from the functor pointer type to the allocator's pointer
-              type */
-           pointer_type victim = static_cast<pointer_type>(f);
+            /* Cast from the functor pointer type to the allocator's pointer
+               type */
+            pointer_type victim = static_cast<pointer_type>(f);
 
-           // Destroy and deallocate the functor
-           allocator.destroy(victim);
-           allocator.deallocate(victim, 1);
+            // Destroy and deallocate the functor
+            allocator.destroy(victim);
+            allocator.deallocate(victim, 1);
 #  else
-           delete f;
+            delete f;
 #  endif // BOOST_NO_STD_ALLOCATOR
+            out_buffer.obj_ptr = 0;
+          } else /* op == check_functor_type_tag */ {
+            const std::type_info& check_type = 
+              *static_cast<const std::type_info*>(out_buffer.const_obj_ptr);
+            if (BOOST_FUNCTION_COMPARE_TYPE_ID(check_type, typeid(Functor)))
+              out_buffer.obj_ptr = in_buffer.obj_ptr;
+            else
+              out_buffer.obj_ptr = 0;
+          }
+        }
+
+        // For function objects, we determine whether the function
+        // object can use the small-object optimization buffer or
+        // whether we need to allocate it on the heap.
+        static inline void
+        manager(const function_buffer& in_buffer, function_buffer& out_buffer, 
+                functor_manager_operation_type op, function_obj_tag)
+        {
+          manager(in_buffer, out_buffer, op,
+                  mpl::bool_<(function_allows_small_object_optimization<functor_type>::value)>());
+        }
 
-           return any_pointer(static_cast<void*>(0));
-         }
-       }
       public:
-       /* Dispatch to an appropriate manager based on whether we have a
-          function pointer or a function object pointer. */
-       static any_pointer
-       manage(any_pointer functor_ptr, functor_manager_operation_type op)
-       {
-         typedef typename get_function_tag<functor_type>::type tag_type;
-         return manager(functor_ptr, op, tag_type());
-       }
-      };
-
-      // value=1 if the given type is not "unusable"
-      template<typename T>
-      struct count_if_used
-      {
-       BOOST_STATIC_CONSTANT(int, value = 1);
+        /* Dispatch to an appropriate manager based on whether we have a
+           function pointer or a function object pointer. */
+        static inline void
+        manage(const function_buffer& in_buffer, function_buffer& out_buffer, 
+               functor_manager_operation_type op)
+        {
+          typedef typename get_function_tag<functor_type>::type tag_type;
+          switch (op) {
+          case get_functor_type_tag:
+            out_buffer.const_obj_ptr = &typeid(functor_type);
+            return;
+
+          default:
+            manager(in_buffer, out_buffer, op, tag_type());
+            return;
+          }
+        }
       };
 
-      // value=0 for unusable types
-      template<>
-      struct count_if_used<unusable>
-      {
-       BOOST_STATIC_CONSTANT(int, value = 0);
-      };
+      // A type that is only used for comparisons against zero
+      struct useless_clear_type {};
+
+#ifdef BOOST_NO_SFINAE
+      // These routines perform comparisons between a Boost.Function
+      // object and an arbitrary function object (when the last
+      // parameter is mpl::bool_<false>) or against zero (when the
+      // last parameter is mpl::bool_<true>). They are only necessary
+      // for compilers that don't support SFINAE.
+      template<typename Function, typename Functor>
+        bool
+        compare_equal(const Function& f, const Functor&, int, mpl::bool_<true>)
+        { return f.empty(); }
+
+      template<typename Function, typename Functor>
+        bool
+        compare_not_equal(const Function& f, const Functor&, int,
+                          mpl::bool_<true>)
+        { return !f.empty(); }
+
+      template<typename Function, typename Functor>
+        bool
+        compare_equal(const Function& f, const Functor& g, long,
+                      mpl::bool_<false>)
+        {
+          if (const Functor* fp = f.template target<Functor>())
+            return function_equal(*fp, g);
+          else return false;
+        }
+
+      template<typename Function, typename Functor>
+        bool
+        compare_equal(const Function& f, const reference_wrapper<Functor>& g,
+                      int, mpl::bool_<false>)
+        {
+          if (const Functor* fp = f.template target<Functor>())
+            return fp == g.get_pointer();
+          else return false;
+        }
+
+      template<typename Function, typename Functor>
+        bool
+        compare_not_equal(const Function& f, const Functor& g, long,
+                          mpl::bool_<false>)
+        {
+          if (const Functor* fp = f.template target<Functor>())
+            return !function_equal(*fp, g);
+          else return true;
+        }
+
+      template<typename Function, typename Functor>
+        bool
+        compare_not_equal(const Function& f,
+                          const reference_wrapper<Functor>& g, int,
+                          mpl::bool_<false>)
+        {
+          if (const Functor* fp = f.template target<Functor>())
+            return fp != g.get_pointer();
+          else return true;
+        }
+#endif // BOOST_NO_SFINAE
 
-      // Count the number of arguments (from the given set) which are not
-      // "unusable" (therefore, count those arguments that are used).
-      template<typename T1, typename T2, typename T3, typename T4,
-              typename T5, typename T6, typename T7, typename T8,
-              typename T9, typename T10>
-      struct count_used_args
+      /**
+       * Stores the "manager" portion of the vtable for a
+       * boost::function object.
+       */
+      struct vtable_base
       {
-       BOOST_STATIC_CONSTANT(int, value =
-                             (count_if_used<T1>::value +
-                              count_if_used<T2>::value +
-                              count_if_used<T3>::value +
-                              count_if_used<T4>::value +
-                              count_if_used<T5>::value +
-                              count_if_used<T6>::value +
-                              count_if_used<T7>::value +
-                              count_if_used<T8>::value +
-                              count_if_used<T9>::value +
-                              count_if_used<T10>::value));
+        vtable_base() : manager(0) { }
+        void (*manager)(const function_buffer& in_buffer, 
+                        function_buffer& out_buffer, 
+                        functor_manager_operation_type op);
       };
     } // end namespace function
   } // end namespace detail
 
-  /**
-   * The function_base class contains the basic elements needed for the
-   * function1, function2, function3, etc. classes. It is common to all
-   * functions (and as such can be used to tell if we have one of the
-   * functionN objects).
-   */
-  class function_base
+/**
+ * The function_base class contains the basic elements needed for the
+ * function1, function2, function3, etc. classes. It is common to all
+ * functions (and as such can be used to tell if we have one of the
+ * functionN objects).
+ */
+class function_base
+{
+public:
+  function_base() : vtable(0) { }
+
+  /** Determine if the function is empty (i.e., has no target). */
+  bool empty() const { return !vtable; }
+
+  /** Retrieve the type of the stored function object, or typeid(void)
+      if this is empty. */
+  const std::type_info& target_type() const
   {
-  public:
-    function_base() : manager(0), functor(static_cast<void*>(0)) {}
+    if (!vtable) return typeid(void);
+
+    detail::function::function_buffer type;
+    vtable->manager(functor, type, detail::function::get_functor_type_tag);
+    return *static_cast<const std::type_info*>(type.const_obj_ptr);
+  }
 
-    // Is this function empty?
-    bool empty() const { return !manager; }
+  template<typename Functor>
+    Functor* target()
+    {
+      if (!vtable) return 0;
 
-  public: // should be protected, but GCC 2.95.3 will fail to allow access
-    detail::function::any_pointer (*manager)(
-                          detail::function::any_pointer,
-                          detail::function::functor_manager_operation_type);
-    detail::function::any_pointer functor;
+      detail::function::function_buffer type_result;
+      type_result.const_obj_ptr = &typeid(Functor);
+      vtable->manager(functor, type_result, 
+                      detail::function::check_functor_type_tag);
+      return static_cast<Functor*>(type_result.obj_ptr);
+    }
 
-#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(); }
+  template<typename Functor>
+#if defined(BOOST_MSVC) && BOOST_WORKAROUND(BOOST_MSVC, < 1300)
+    const Functor* target( Functor * = 0 ) const
 #else
-  private:
-    struct dummy {
-      void nonnull() {};
-    };
+    const Functor* target() const
+#endif
+    {
+      if (!vtable) return 0;
+
+      detail::function::function_buffer type_result;
+      type_result.const_obj_ptr = &typeid(Functor);
+      vtable->manager(functor, type_result, 
+                      detail::function::check_functor_type_tag);
+      // GCC 2.95.3 gets the CV qualifiers wrong here, so we
+      // can't do the static_cast that we should do.
+      return (const Functor*)(type_result.obj_ptr);
+    }
 
-    typedef void (dummy::*safe_bool)();
+  template<typename F>
+    bool contains(const F& f) const
+    {
+#if defined(BOOST_MSVC) && BOOST_WORKAROUND(BOOST_MSVC, < 1300)
+      if (const F* fp = this->target( (F*)0 ))
+#else
+      if (const F* fp = this->template target<F>())
+#endif
+      {
+        return function_equal(*fp, f);
+      } else {
+        return false;
+      }
+    }
 
-  public:
-    operator safe_bool () const
-      { return (this->empty())? 0 : &dummy::nonnull; }
+#if defined(__GNUC__) && __GNUC__ == 3 && __GNUC_MINOR__ <= 3
+  // GCC 3.3 and newer cannot copy with the global operator==, due to
+  // problems with instantiation of function return types before it
+  // has been verified that the argument types match up.
+  template<typename Functor>
+    BOOST_FUNCTION_ENABLE_IF_NOT_INTEGRAL(Functor, bool)
+    operator==(Functor g) const
+    {
+      if (const Functor* fp = target<Functor>())
+        return function_equal(*fp, g);
+      else return false;
+    }
 
-    safe_bool operator!() const
-      { return (this->empty())? &dummy::nonnull : 0; }
+  template<typename Functor>
+    BOOST_FUNCTION_ENABLE_IF_NOT_INTEGRAL(Functor, bool)
+    operator!=(Functor g) const
+    {
+      if (const Functor* fp = target<Functor>())
+        return !function_equal(*fp, g);
+      else return true;
+    }
 #endif
-  };
 
-  /* Poison comparison between Boost.Function objects (because it is
-   * meaningless). The comparisons would otherwise be allowed because of the
-   * conversion required to allow syntax such as:
-   *   boost::function<int, int> f;
-   *   if (f) { f(5); }
-   */
-  void operator==(const function_base&, const function_base&);
-  void operator!=(const function_base&, const function_base&);
+public: // should be protected, but GCC 2.95.3 will fail to allow access
+  detail::function::vtable_base* vtable;
+  mutable detail::function::function_buffer functor;
+};
+
+/**
+ * The bad_function_call exception class is thrown when a boost::function
+ * object is invoked
+ */
+class bad_function_call : public std::runtime_error
+{
+public:
+  bad_function_call() : std::runtime_error("call to empty boost::function") {}
+};
+
+#ifndef BOOST_NO_SFINAE
+inline bool operator==(const function_base& f,
+                       detail::function::useless_clear_type*)
+{
+  return f.empty();
+}
 
-  namespace detail {
-    namespace function {
-      inline bool has_empty_target(const function_base* f)
-      {
-       return f->empty();
-      }
+inline bool operator!=(const function_base& f,
+                       detail::function::useless_clear_type*)
+{
+  return !f.empty();
+}
 
-      inline bool has_empty_target(...)
-      {
-       return false;
-      }
-    } // end namespace function
-  } // end namespace detail
+inline bool operator==(detail::function::useless_clear_type*,
+                       const function_base& f)
+{
+  return f.empty();
+}
+
+inline bool operator!=(detail::function::useless_clear_type*,
+                       const function_base& f)
+{
+  return !f.empty();
+}
+#endif
 
-  // The default function policy is to do nothing before and after the call.
-  struct empty_function_policy
+#ifdef BOOST_NO_SFINAE
+// Comparisons between boost::function objects and arbitrary function objects
+template<typename Functor>
+  inline bool operator==(const function_base& f, Functor g)
   {
-    inline void precall(const function_base*) {}
-    inline void postcall(const function_base*) {}
-  };
-
-  // The default function mixin does nothing. The assignment and
-  // copy-construction operators are all defined because MSVC defines broken
-  // versions.
-  struct empty_function_mixin
+    typedef mpl::bool_<(is_integral<Functor>::value)> integral;
+    return detail::function::compare_equal(f, g, 0, integral());
+  }
+
+template<typename Functor>
+  inline bool operator==(Functor g, const function_base& f)
   {
-    empty_function_mixin() {}
-    empty_function_mixin(const empty_function_mixin&) {}
+    typedef mpl::bool_<(is_integral<Functor>::value)> integral;
+    return detail::function::compare_equal(f, g, 0, integral());
+  }
 
-    empty_function_mixin& operator=(const empty_function_mixin&)
+template<typename Functor>
+  inline bool operator!=(const function_base& f, Functor g)
+  {
+    typedef mpl::bool_<(is_integral<Functor>::value)> integral;
+    return detail::function::compare_not_equal(f, g, 0, integral());
+  }
+
+template<typename Functor>
+  inline bool operator!=(Functor g, const function_base& f)
+  {
+    typedef mpl::bool_<(is_integral<Functor>::value)> integral;
+    return detail::function::compare_not_equal(f, g, 0, integral());
+  }
+#else
+
+#  if !(defined(__GNUC__) && __GNUC__ == 3 && __GNUC_MINOR__ <= 3)
+// Comparisons between boost::function objects and arbitrary function
+// objects. GCC 3.3 and before has an obnoxious bug that prevents this
+// from working.
+template<typename Functor>
+  BOOST_FUNCTION_ENABLE_IF_NOT_INTEGRAL(Functor, bool)
+  operator==(const function_base& f, Functor g)
+  {
+    if (const Functor* fp = f.template target<Functor>())
+      return function_equal(*fp, g);
+    else return false;
+  }
+
+template<typename Functor>
+  BOOST_FUNCTION_ENABLE_IF_NOT_INTEGRAL(Functor, bool)
+  operator==(Functor g, const function_base& f)
+  {
+    if (const Functor* fp = f.template target<Functor>())
+      return function_equal(g, *fp);
+    else return false;
+  }
+
+template<typename Functor>
+  BOOST_FUNCTION_ENABLE_IF_NOT_INTEGRAL(Functor, bool)
+  operator!=(const function_base& f, Functor g)
+  {
+    if (const Functor* fp = f.template target<Functor>())
+      return !function_equal(*fp, g);
+    else return true;
+  }
+
+template<typename Functor>
+  BOOST_FUNCTION_ENABLE_IF_NOT_INTEGRAL(Functor, bool)
+  operator!=(Functor g, const function_base& f)
+  {
+    if (const Functor* fp = f.template target<Functor>())
+      return !function_equal(g, *fp);
+    else return true;
+  }
+#  endif
+
+template<typename Functor>
+  BOOST_FUNCTION_ENABLE_IF_NOT_INTEGRAL(Functor, bool)
+  operator==(const function_base& f, reference_wrapper<Functor> g)
+  {
+    if (const Functor* fp = f.template target<Functor>())
+      return fp == g.get_pointer();
+    else return false;
+  }
+
+template<typename Functor>
+  BOOST_FUNCTION_ENABLE_IF_NOT_INTEGRAL(Functor, bool)
+  operator==(reference_wrapper<Functor> g, const function_base& f)
+  {
+    if (const Functor* fp = f.template target<Functor>())
+      return g.get_pointer() == fp;
+    else return false;
+  }
+
+template<typename Functor>
+  BOOST_FUNCTION_ENABLE_IF_NOT_INTEGRAL(Functor, bool)
+  operator!=(const function_base& f, reference_wrapper<Functor> g)
+  {
+    if (const Functor* fp = f.template target<Functor>())
+      return fp != g.get_pointer();
+    else return true;
+  }
+
+template<typename Functor>
+  BOOST_FUNCTION_ENABLE_IF_NOT_INTEGRAL(Functor, bool)
+  operator!=(reference_wrapper<Functor> g, const function_base& f)
+  {
+    if (const Functor* fp = f.template target<Functor>())
+      return g.get_pointer() != fp;
+    else return true;
+  }
+
+#endif // Compiler supporting SFINAE
+
+namespace detail {
+  namespace function {
+    inline bool has_empty_target(const function_base* f)
     {
-      return *this;
+      return f->empty();
     }
-  };
-}
+
+#if BOOST_WORKAROUND(BOOST_MSVC, <= 1310)
+    inline bool has_empty_target(const void*)
+    {
+      return false;
+    }
+#else
+    inline bool has_empty_target(...)
+    {
+      return false;
+    }
+#endif
+  } // end namespace function
+} // end namespace detail
+} // end namespace boost
+
+#undef BOOST_FUNCTION_ENABLE_IF_NOT_INTEGRAL
+#undef BOOST_FUNCTION_COMPARE_TYPE_ID
 
 #endif // BOOST_FUNCTION_BASE_HEADER