Source

GL Profile Suite / boost_1_51_0 / boost / function / function_base.hpp

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
// Boost.Function library

//  Copyright Douglas Gregor 2001-2006
//  Copyright Emil Dotchevski 2007
//  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 <stdexcept>
#include <string>
#include <memory>
#include <new>
#include <boost/config.hpp>
#include <boost/detail/sp_typeinfo.hpp>
#include <boost/assert.hpp>
#include <boost/integer.hpp>
#include <boost/type_traits/has_trivial_copy.hpp>
#include <boost/type_traits/has_trivial_destructor.hpp>
#include <boost/type_traits/is_const.hpp>
#include <boost/type_traits/is_integral.hpp>
#include <boost/type_traits/is_volatile.hpp>
#include <boost/type_traits/composite_traits.hpp>
#include <boost/type_traits/ice.hpp>
#include <boost/ref.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>
#include <boost/function/function_fwd.hpp>

#if defined(BOOST_MSVC)
#   pragma warning( push )
#   pragma warning( disable : 4793 ) // complaint about native code generation
#   pragma warning( disable : 4127 ) // "conditional expression is constant"
#endif       

// Define BOOST_FUNCTION_STD_NS to the namespace that contains type_info.
#ifdef BOOST_NO_STD_TYPEINFO
// Embedded VC++ does not have type_info in namespace std
#  define BOOST_FUNCTION_STD_NS
#else
#  define BOOST_FUNCTION_STD_NS std
#endif

// Borrowed from Boost.Python library: determines the cases where we
// need to use std::type_info::name to compare instead of operator==.
#if defined( BOOST_NO_TYPEID )
#  define BOOST_FUNCTION_COMPARE_TYPE_ID(X,Y) ((X)==(Y))
#elif (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 && !defined(BOOST_STRICT_CONFIG)
#  define BOOST_FUNCTION_TARGET_FIX(x) x
#else
#  define BOOST_FUNCTION_TARGET_FIX(x)
#endif // not MSVC

#if !BOOST_WORKAROUND(__BORLANDC__, < 0x5A0)
#  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

namespace boost {
  namespace detail {
    namespace function {
      class X;

      /**
       * 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
      {
        // For pointers to function objects
        mutable void* obj_ptr;

        // For pointers to std::type_info objects
        struct type_t {
          // (get_functor_type_tag, check_functor_type_tag).
          const detail::sp_typeinfo* type;

          // Whether the type is const-qualified.
          bool const_qualified;
          // Whether the type is volatile-qualified.
          bool volatile_qualified;
        } type;

        // 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;

        // For references to function objects. We explicitly keep
        // track of the cv-qualifiers on the object referenced.
        struct obj_ref_t {
          mutable void* obj_ptr;
          bool is_const_qualified;
          bool is_volatile_qualified;
        } obj_ref;

        // To relax aliasing constraints
        mutable char data;
      };

      /**
       * The unusable class is a placeholder for unused function arguments
       * It is also completely unusable except that it constructable from
       * anything. This helps compilers without partial specialization to
       * handle Boost.Function objects returning void.
       */
      struct unusable
      {
        unusable() {}
        template<typename T> unusable(const T&) {}
      };

      /* Determine the return type. This supports compilers that do not support
       * void returns or partial specialization by silently changing the return
       * type to "unusable".
       */
      template<typename T> struct function_return_type { typedef T type; };

      template<>
      struct function_return_type<void>
      {
        typedef unusable type;
      };

      // The operation type to perform on the given functor/function pointer
      enum functor_manager_operation_type {
        clone_functor_tag,
        move_functor_tag,
        destroy_functor_tag,
        check_functor_type_tag,
        get_functor_type_tag
      };

      // Tags used to decide between different types of functions
      struct function_ptr_tag {};
      struct function_obj_tag {};
      struct member_ptr_tag {};
      struct function_obj_ref_tag {};

      template<typename F>
      class get_function_tag
      {
        typedef typename mpl::if_c<(is_pointer<F>::value),
                                   function_ptr_tag,
                                   function_obj_tag>::type ptr_or_obj_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 mpl::if_c<(is_reference_wrapper<F>::value),
                                   function_obj_ref_tag,
                                   ptr_or_obj_or_mem_tag>::type or_ref_tag;

      public:
        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).
      template<typename F>
      struct reference_manager
      {
        static inline void
        manage(const function_buffer& in_buffer, function_buffer& out_buffer, 
               functor_manager_operation_type op)
        {
          switch (op) {
          case clone_functor_tag: 
            out_buffer.obj_ref = in_buffer.obj_ref;
            return;

          case move_functor_tag:
            out_buffer.obj_ref = in_buffer.obj_ref;
            in_buffer.obj_ref.obj_ptr = 0;
            return;

          case destroy_functor_tag:
            out_buffer.obj_ref.obj_ptr = 0;
            return;

          case check_functor_type_tag:
            {
              const detail::sp_typeinfo& check_type 
                = *out_buffer.type.type;

              // Check whether we have the same type. We can add
              // cv-qualifiers, but we can't take them away.
              if (BOOST_FUNCTION_COMPARE_TYPE_ID(check_type, BOOST_SP_TYPEID(F))
                  && (!in_buffer.obj_ref.is_const_qualified 
                      || out_buffer.type.const_qualified)
                  && (!in_buffer.obj_ref.is_volatile_qualified
                      || out_buffer.type.volatile_qualified))
                out_buffer.obj_ptr = in_buffer.obj_ref.obj_ptr;
              else
                out_buffer.obj_ptr = 0;
            }
            return;

          case get_functor_type_tag:
            out_buffer.type.type = &BOOST_SP_TYPEID(F);
            out_buffer.type.const_qualified = in_buffer.obj_ref.is_const_qualified;
            out_buffer.type.volatile_qualified = in_buffer.obj_ref.is_volatile_qualified;
            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))));
      };

      template <typename F,typename A>
      struct functor_wrapper: public F, public A
      {
        functor_wrapper( F f, A a ):
          F(f),
          A(a)
        {
        }
        
        functor_wrapper(const functor_wrapper& f) :
          F(static_cast<const F&>(f)),
          A(static_cast<const A&>(f))
        {
        }
      };

      /**
       * The functor_manager class contains a static function "manage" which
       * can clone or destroy the given function/function object pointer.
       */
      template<typename Functor>
      struct functor_manager_common
      {
        typedef Functor functor_type;

        // Function pointers
        static inline void
        manage_ptr(const function_buffer& in_buffer, function_buffer& out_buffer, 
                functor_manager_operation_type op)
        {
          if (op == clone_functor_tag)
            out_buffer.func_ptr = in_buffer.func_ptr;
          else if (op == move_functor_tag) {
            out_buffer.func_ptr = in_buffer.func_ptr;
            in_buffer.func_ptr = 0;
          } else if (op == destroy_functor_tag)
            out_buffer.func_ptr = 0;
          else if (op == check_functor_type_tag) {
            const detail::sp_typeinfo& check_type 
              = *out_buffer.type.type;
            if (BOOST_FUNCTION_COMPARE_TYPE_ID(check_type, BOOST_SP_TYPEID(Functor)))
              out_buffer.obj_ptr = &in_buffer.func_ptr;
            else
              out_buffer.obj_ptr = 0;
          } else /* op == get_functor_type_tag */ {
            out_buffer.type.type = &BOOST_SP_TYPEID(Functor);
            out_buffer.type.const_qualified = false;
            out_buffer.type.volatile_qualified = false;
          }
        }

        // Function objects that fit in the small-object buffer.
        static inline void
        manage_small(const function_buffer& in_buffer, function_buffer& out_buffer, 
                functor_manager_operation_type op)
        {
          if (op == clone_functor_tag || op == move_functor_tag) {
            const functor_type* in_functor = 
              reinterpret_cast<const functor_type*>(&in_buffer.data);
            new (reinterpret_cast<void*>(&out_buffer.data)) functor_type(*in_functor);

            if (op == move_functor_tag) {
              functor_type* f = reinterpret_cast<functor_type*>(&in_buffer.data);
              (void)f; // suppress warning about the value of f not being used (MSVC)
              f->~Functor();
            }
          } else if (op == destroy_functor_tag) {
            // Some compilers (Borland, vc6, ...) are unhappy with ~functor_type.
             functor_type* f = reinterpret_cast<functor_type*>(&out_buffer.data);
             (void)f; // suppress warning about the value of f not being used (MSVC)
             f->~Functor();
          } else if (op == check_functor_type_tag) {
            const detail::sp_typeinfo& check_type 
              = *out_buffer.type.type;
            if (BOOST_FUNCTION_COMPARE_TYPE_ID(check_type, BOOST_SP_TYPEID(Functor)))
              out_buffer.obj_ptr = &in_buffer.data;
            else
              out_buffer.obj_ptr = 0;
          } else /* op == get_functor_type_tag */ {
            out_buffer.type.type = &BOOST_SP_TYPEID(Functor);
            out_buffer.type.const_qualified = false;
            out_buffer.type.volatile_qualified = false;            
          }
        }
      };

      template<typename Functor>
      struct functor_manager
      {
      private:
        typedef Functor functor_type;

        // Function pointers
        static inline void
        manager(const function_buffer& in_buffer, function_buffer& out_buffer, 
                functor_manager_operation_type op, function_ptr_tag)
        {
          functor_manager_common<Functor>::manage_ptr(in_buffer,out_buffer,op);
        }

        // 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_)
        {
          functor_manager_common<Functor>::manage_small(in_buffer,out_buffer,op);
        }
        
        // 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_)
        {
          if (op == clone_functor_tag) {
            // Clone the functor
            // GCC 2.95.3 gets the CV qualifiers wrong here, so we
            // can't do the static_cast that we should do.
            // jewillco: Changing this to static_cast because GCC 2.95.3 is
            // obsolete.
            const functor_type* f =
              static_cast<const functor_type*>(in_buffer.obj_ptr);
            functor_type* new_f = new functor_type(*f);
            out_buffer.obj_ptr = new_f;
          } else if (op == move_functor_tag) {
            out_buffer.obj_ptr = in_buffer.obj_ptr;
            in_buffer.obj_ptr = 0;
          } 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);
            delete f;
            out_buffer.obj_ptr = 0;
          } else if (op == check_functor_type_tag) {
            const detail::sp_typeinfo& check_type
              = *out_buffer.type.type;
            if (BOOST_FUNCTION_COMPARE_TYPE_ID(check_type, BOOST_SP_TYPEID(Functor)))
              out_buffer.obj_ptr = in_buffer.obj_ptr;
            else
              out_buffer.obj_ptr = 0;
          } else /* op == get_functor_type_tag */ {
            out_buffer.type.type = &BOOST_SP_TYPEID(Functor);
            out_buffer.type.const_qualified = false;
            out_buffer.type.volatile_qualified = false;
          }
        }

        // 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)>());
        }

        // For member pointers, we use the small-object optimization buffer.
        static inline void
        manager(const function_buffer& in_buffer, function_buffer& out_buffer, 
                functor_manager_operation_type op, member_ptr_tag)
        {
          manager(in_buffer, out_buffer, op, mpl::true_());
        }

      public:
        /* 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.type.type = &BOOST_SP_TYPEID(functor_type);
            out_buffer.type.const_qualified = false;
            out_buffer.type.volatile_qualified = false;
            return;

          default:
            manager(in_buffer, out_buffer, op, tag_type());
            return;
          }
        }
      };

      template<typename Functor, typename Allocator>
      struct functor_manager_a
      {
      private:
        typedef Functor functor_type;

        // Function pointers
        static inline void
        manager(const function_buffer& in_buffer, function_buffer& out_buffer, 
                functor_manager_operation_type op, function_ptr_tag)
        {
          functor_manager_common<Functor>::manage_ptr(in_buffer,out_buffer,op);
        }

        // 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_)
        {
          functor_manager_common<Functor>::manage_small(in_buffer,out_buffer,op);
        }
        
        // 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_)
        {
          typedef functor_wrapper<Functor,Allocator> functor_wrapper_type;
          typedef typename Allocator::template rebind<functor_wrapper_type>::other
            wrapper_allocator_type;
          typedef typename wrapper_allocator_type::pointer wrapper_allocator_pointer_type;

          if (op == clone_functor_tag) {
            // Clone the functor
            // GCC 2.95.3 gets the CV qualifiers wrong here, so we
            // can't do the static_cast that we should do.
            const functor_wrapper_type* f =
              static_cast<const functor_wrapper_type*>(in_buffer.obj_ptr);
            wrapper_allocator_type wrapper_allocator(static_cast<Allocator const &>(*f));
            wrapper_allocator_pointer_type copy = wrapper_allocator.allocate(1);
            wrapper_allocator.construct(copy, *f);

            // Get back to the original pointer type
            functor_wrapper_type* new_f = static_cast<functor_wrapper_type*>(copy);
            out_buffer.obj_ptr = new_f;
          } else if (op == move_functor_tag) {
            out_buffer.obj_ptr = in_buffer.obj_ptr;
            in_buffer.obj_ptr = 0;
          } else if (op == destroy_functor_tag) {
            /* Cast from the void pointer to the functor_wrapper_type */
            functor_wrapper_type* victim =
              static_cast<functor_wrapper_type*>(in_buffer.obj_ptr);
            wrapper_allocator_type wrapper_allocator(static_cast<Allocator const &>(*victim));
            wrapper_allocator.destroy(victim);
            wrapper_allocator.deallocate(victim,1);
            out_buffer.obj_ptr = 0;
          } else if (op == check_functor_type_tag) {
            const detail::sp_typeinfo& check_type 
              = *out_buffer.type.type;
            if (BOOST_FUNCTION_COMPARE_TYPE_ID(check_type, BOOST_SP_TYPEID(Functor)))
              out_buffer.obj_ptr = in_buffer.obj_ptr;
            else
              out_buffer.obj_ptr = 0;
          } else /* op == get_functor_type_tag */ {
            out_buffer.type.type = &BOOST_SP_TYPEID(Functor);
            out_buffer.type.const_qualified = false;
            out_buffer.type.volatile_qualified = false;
          }
        }

        // 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)>());
        }

      public:
        /* 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.type.type = &BOOST_SP_TYPEID(functor_type);
            out_buffer.type.const_qualified = false;
            out_buffer.type.volatile_qualified = false;
            return;

          default:
            manager(in_buffer, out_buffer, op, tag_type());
            return;
          }
        }
      };

      // 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

      /**
       * Stores the "manager" portion of the vtable for a
       * boost::function object.
       */
      struct vtable_base
      {
        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
{
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 BOOST_SP_TYPEID(void)
      if this is empty. */
  const detail::sp_typeinfo& target_type() const
  {
    if (!vtable) return BOOST_SP_TYPEID(void);

    detail::function::function_buffer type;
    get_vtable()->manager(functor, type, detail::function::get_functor_type_tag);
    return *type.type.type;
  }

  template<typename Functor>
    Functor* target()
    {
      if (!vtable) return 0;

      detail::function::function_buffer type_result;
      type_result.type.type = &BOOST_SP_TYPEID(Functor);
      type_result.type.const_qualified = is_const<Functor>::value;
      type_result.type.volatile_qualified = is_volatile<Functor>::value;
      get_vtable()->manager(functor, type_result, 
                      detail::function::check_functor_type_tag);
      return static_cast<Functor*>(type_result.obj_ptr);
    }

  template<typename Functor>
#if defined(BOOST_MSVC) && BOOST_WORKAROUND(BOOST_MSVC, < 1300)
    const Functor* target( Functor * = 0 ) const
#else
    const Functor* target() const
#endif
    {
      if (!vtable) return 0;

      detail::function::function_buffer type_result;
      type_result.type.type = &BOOST_SP_TYPEID(Functor);
      type_result.type.const_qualified = true;
      type_result.type.volatile_qualified = is_volatile<Functor>::value;
      get_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 static_cast<const Functor*>(type_result.obj_ptr);
    }

  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;
      }
    }

#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;
    }

  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

public: // should be protected, but GCC 2.95.3 will fail to allow access
  detail::function::vtable_base* get_vtable() const {
    return reinterpret_cast<detail::function::vtable_base*>(
             reinterpret_cast<std::size_t>(vtable) & ~static_cast<std::size_t>(0x01));
  }

  bool has_trivial_copy_and_destroy() const {
    return reinterpret_cast<std::size_t>(vtable) & 0x01;
  }

  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();
}

inline bool operator!=(const function_base& f,
                       detail::function::useless_clear_type*)
{
  return !f.empty();
}

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

#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)
  {
    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)
  {
    typedef mpl::bool_<(is_integral<Functor>::value)> integral;
    return detail::function::compare_equal(f, g, 0, integral());
  }

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 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

#if defined(BOOST_MSVC)
#   pragma warning( pop )
#endif       

#endif // BOOST_FUNCTION_BASE_HEADER