File: circular_buffer_base.hpp

package info (click to toggle)
monotone 0.40-7
  • links: PTS
  • area: main
  • in suites: lenny
  • size: 24,064 kB
  • ctags: 17,296
  • sloc: cpp: 98,733; ansic: 83,690; sh: 6,065; lisp: 957; makefile: 777; perl: 715; python: 312; sql: 104; sed: 16
file content (1579 lines) | stat: -rw-r--r-- 58,931 bytes parent folder | download | duplicates (6)
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
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
// Implementation of the base circular buffer.

// Copyright (c) 2003
// Jan Gaspar, Whitestein Technologies

// Permission to use or copy this software for any purpose is hereby granted 
// without fee, provided the above notices are retained on all copies.
// Permission to modify the code and to distribute modified code is granted,
// provided the above notices are retained, and a notice that the code was
// modified is included with the above copyright notice.

// This material is provided "as is", with absolutely no warranty expressed
// or implied. Any use is at your own risk.

#if !defined(BOOST_CIRCULAR_BUFFER_BASE_HPP)
#define BOOST_CIRCULAR_BUFFER_BASE_HPP

#include <boost/concept_check.hpp>
#include <boost/iterator.hpp>
#include <boost/iterator_adaptors.hpp>
#include <boost/call_traits.hpp>
#include <boost/type_traits.hpp>
#include <boost/throw_exception.hpp>
#include <boost/assert.hpp>
#include <boost/version.hpp>

#if BOOST_VERSION >= 103100
#include <boost/iterator/reverse_iterator.hpp>
#endif

#include <memory>
#include <algorithm>
#if !defined(BOOST_NO_EXCEPTIONS)
    #include <stdexcept>
#endif

namespace boost {

// Exception handling macros.
#if !defined(BOOST_NO_EXCEPTIONS)
    #define BOOST_CB_TRY try {
    #define BOOST_CB_UNWIND(action) } catch(...) { action; throw; }
#else
    #define BOOST_CB_TRY
    #define BOOST_CB_UNWIND(action)
#endif

namespace cb_details {

/*
    \struct cb_int_iterator_tag
    \brief Identifying tag for integer types (not for iterators).
*/
struct cb_int_iterator_tag {};

/*
    \struct cb_iterator_category
    \brief Defines iterator category.
*/
template <bool>
struct cb_iterator_category {
    //! Represents iterators.
    typedef std::input_iterator_tag iterator_category;
};

template <>
struct cb_iterator_category<true> {
    //! Represents integral types (not iterators).
    typedef cb_int_iterator_tag iterator_category;
};

/*
    \struct cb_iterator_category_traits
    \brief Defines the iterator category tag for the given iterator.
*/
template <class Iterator>
struct cb_iterator_category_traits {
    //! Iterator category tag type.
    /*!
        Depending on the template parameter the <tt>tag</tt> distinguishes
        between iterators and non-iterators. If the template parameter
        is an iterator the <tt>tag</tt> is typedef for <tt>std::input_iterator_tag</tt>.
        If the parameter is not an iterator the <tt>tag</tt> is typedef for
        <tt>cb_int_iterator_tag</tt>.
    */
    typedef typename cb_details::cb_iterator_category<
        is_integral<Iterator>::value>::iterator_category tag;
};

template <class Traits> struct cb_nonconst_traits;

/*
    \struct cb_const_traits
    \brief Defines the data types for a const iterator.
    \param Traits Defines the basic types.
*/
template <class Traits>
struct cb_const_traits {
// Basic types
    typedef typename Traits::value_type value_type;
    typedef typename Traits::const_pointer pointer;
    typedef typename Traits::const_reference reference;
    typedef typename Traits::size_type size_type;
    typedef typename Traits::difference_type difference_type;

// Non-const traits
    typedef cb_nonconst_traits<Traits> nonconst_traits;
};

/*
    \struct cb_nonconst_traits
    \brief Defines the data types for a non-const iterator.
    \param Traits Defines the basic types.
*/
template <class Traits>
struct cb_nonconst_traits {
// Basic types
    typedef typename Traits::value_type value_type;
    typedef typename Traits::pointer pointer;
    typedef typename Traits::reference reference;
    typedef typename Traits::size_type size_type;
    typedef typename Traits::difference_type difference_type;

// Non-const traits
    typedef cb_nonconst_traits<Traits> nonconst_traits;
};

/*
    \struct cb_internal_pointer
    \brief Helper pointer used in the cb_iterator.
*/
template <class Traits0>
struct cb_helper_pointer {
    bool m_end;
    typename Traits0::pointer m_it;
};

/*
    \class cb_iterator
    \brief Random access iterator for the circular buffer.
    \param Buff The type of the underlying circular buffer.
    \param Traits Defines basic iterator types.
    \note This iterator is not circular. It was designed
          for iterating from begin() to end() of the circular buffer.
*/
template <class Buff, class Traits> 
class cb_iterator : 
    public boost::iterator< 
        std::random_access_iterator_tag,
        typename Traits::value_type,
        typename Traits::difference_type,
        typename Traits::pointer,
        typename Traits::reference>
{
private:
// Helper types

    //! Base iterator.
    typedef boost::iterator<
        std::random_access_iterator_tag,
        typename Traits::value_type,
        typename Traits::difference_type,
        typename Traits::pointer,
        typename Traits::reference> base_type;

    //! Non-const iterator.
    typedef cb_iterator<Buff, typename Traits::nonconst_traits> nonconst_self;

public:
// Basic types

    //! The type of the elements stored in the circular buffer.
    typedef typename base_type::value_type value_type;

    //! Pointer to the element.
    typedef typename base_type::pointer pointer;

    //! Reference to the element.
    typedef typename base_type::reference reference;

    //! Size type.
    typedef typename Traits::size_type size_type;

    //! Difference type.
    typedef typename base_type::difference_type difference_type;

public:
// Member variables

    //! The circular buffer where the iterator points to.
    const Buff* m_buff;

    //! An internal iterator.
    pointer m_it;

public:
// Construction & assignment

    // Default copy constructor.

    //! Default constructor.
    cb_iterator() : m_buff(0), m_it(0) {}

    //! Copy constructor (used for converting from a non-const to a const iterator).
    cb_iterator(const nonconst_self& it)
        : m_buff(it.m_buff), m_it(it.m_it) {}

    //! Internal constructor.
    /*!
        \note This constructor is not intended to be used directly by the user.
    */
    cb_iterator(const Buff* cb, const pointer it)
        : m_buff(cb), m_it(it) {}

    // Default assign operator.

public:
// Random access iterator methods

    //! Dereferencing operator.
    reference operator * () const {
        BOOST_ASSERT(m_buff != 0); // uninitialized iterator
        BOOST_ASSERT(m_it != 0); // iterator pointing to the end
        return *m_it;
    }

    //! Dereferencing operator.
    pointer operator -> () const { return &(operator*()); }

    //! Difference operator.
    difference_type operator - (const cb_iterator& it) const {
        BOOST_ASSERT(m_buff != 0); // uninitialized iterator
        BOOST_ASSERT(it.m_buff != 0); // uninitialized iterator
        BOOST_ASSERT(m_buff == it.m_buff); // iterators of different containers or invalidated iterator
        cb_helper_pointer<Traits> lhs = create_helper_pointer(*this);
        cb_helper_pointer<Traits> rhs = create_helper_pointer(it);
        if (less(rhs, lhs) && lhs.m_it <= rhs.m_it)
            return lhs.m_it + m_buff->capacity() - rhs.m_it;
        if (less(lhs, rhs) && lhs.m_it >= rhs.m_it)
            return lhs.m_it - m_buff->capacity() - rhs.m_it;
        return lhs.m_it - rhs.m_it;
    }

    //! Increment operator (prefix).
    cb_iterator& operator ++ () {
        BOOST_ASSERT(m_buff != 0); // uninitialized iterator
        BOOST_ASSERT(m_it != 0); // iterator pointing to the end
        m_buff->increment(m_it);
        if (m_it == m_buff->m_last)
            m_it = 0;
        return *this;
    }

    //! Increment operator (postfix).
    cb_iterator operator ++ (int) {
        cb_iterator tmp = *this;
        ++*this;
        return tmp;
    }

    //! Decrement operator (prefix).
    cb_iterator& operator -- () {
        BOOST_ASSERT(m_buff != 0); // uninitialized iterator
        if (m_it == 0)
            m_it = m_buff->m_last;
        m_buff->decrement(m_it);
        return *this;
    }

    //! Decrement operator (postfix).
    cb_iterator operator -- (int) {
        cb_iterator tmp = *this;
        --*this;
        return tmp;
    }

    //! Iterator addition.
    cb_iterator& operator += (difference_type n) {
        if (n > 0) {
            BOOST_ASSERT(m_buff != 0); // uninitialized iterator
            BOOST_ASSERT(m_it != 0); // iterator pointing to the end
            m_it = m_buff->add(m_it, n);
            if (m_it == m_buff->m_last)
                m_it = 0;
        } else if (n < 0) {
            *this -= -n;
        }
        return *this;
    }

    //! Iterator addition.
    cb_iterator operator + (difference_type n) const { return cb_iterator(*this) += n; }

    //! Iterator subtraction.
    cb_iterator& operator -= (difference_type n) {
        if (n > 0) {
            BOOST_ASSERT(m_buff != 0);
            m_it = m_buff->sub(m_it == 0 ? m_buff->m_last : m_it, n);
        } else if (n < 0) {
            *this += -n;
        }
        return *this;
    }

    //! Iterator subtraction.
    cb_iterator operator - (difference_type n) const { return cb_iterator(*this) -= n; }

    //! Element access operator.
    reference operator [] (difference_type n) const { return *(*this + n); }

public:
// Equality & comparison

    //! Equality.
    template <class Traits0>
    bool operator == (const cb_iterator<Buff, Traits0>& it) const {
        BOOST_ASSERT(m_buff != 0); // uninitialized iterator
        BOOST_ASSERT(it.m_buff != 0); // uninitialized iterator
        BOOST_ASSERT(m_buff == it.m_buff); // iterators of different containers or invalidated iterator
        return m_it == it.m_it;
    }

    //! Inequality.
    template <class Traits0>
    bool operator != (const cb_iterator<Buff, Traits0>& it) const {
        BOOST_ASSERT(m_buff != 0); // uninitialized iterator
        BOOST_ASSERT(it.m_buff != 0); // uninitialized iterator
        BOOST_ASSERT(m_buff == it.m_buff); // iterators of different containers or invalidated iterator
        return m_it != it.m_it;
    }

    //! Less.
    template <class Traits0>
    bool operator < (const cb_iterator<Buff, Traits0>& it) const {
        BOOST_ASSERT(m_buff != 0); // uninitialized iterator
        BOOST_ASSERT(it.m_buff != 0); // uninitialized iterator
        BOOST_ASSERT(m_buff == it.m_buff); // iterators of different containers or invalidated iterator
        return less(create_helper_pointer(*this), create_helper_pointer(it));
    }

    //! Greater.
    template <class Traits0>
    bool operator > (const cb_iterator<Buff, Traits0>& it) const  { return it < *this; }

    //! Less or equal.
    template <class Traits0>
    bool operator <= (const cb_iterator<Buff, Traits0>& it) const { return !(it < *this); }

    //! Greater or equal.
    template <class Traits0>
    bool operator >= (const cb_iterator<Buff, Traits0>& it) const { return !(*this < it); }

private:
// Helpers

    //! Create helper pointer.
    template <class Traits0>
    cb_helper_pointer<Traits0> create_helper_pointer(const cb_iterator<Buff, Traits0>& it) const {
        cb_helper_pointer<Traits0> helper;
        helper.m_end = (it.m_it == 0);
        helper.m_it = helper.m_end ? m_buff->m_last : it.m_it;
        return helper;
    }

    //! Compare two pointers.
    /*!
        \return 1 if p1 is greater than p2.
        \return 0 if p1 is equal to p2.
        \return -1 if p1 is lower than p2.
    */
    template <class Pointer0, class Pointer1>
    static difference_type compare(Pointer0 p1, Pointer1 p2) {
        return p1 < p2 ? -1 : (p1 > p2 ? 1 : 0);
    }

    //! Less.
    template <class InternalIterator0, class InternalIterator1>
    bool less(const InternalIterator0& lhs, const InternalIterator1& rhs) const {
        switch (compare(lhs.m_it, m_buff->m_first)) {
        case -1:
            switch (compare(rhs.m_it, m_buff->m_first)) {
            case -1: return lhs.m_it < rhs.m_it;
            case 0: return rhs.m_end;
            case 1: return false;
            }
        case 0:
            switch (compare(rhs.m_it, m_buff->m_first)) {
            case -1: return !lhs.m_end;
            case 0: return !lhs.m_end && rhs.m_end;
            case 1: return !lhs.m_end;
            }
        case 1:
            switch (compare(rhs.m_it, m_buff->m_first)) {
            case -1: return true;
            case 0: return rhs.m_end;
            case 1: return lhs.m_it < rhs.m_it;
            }
        }
        return false;
    }
};

//! Iterator addition.
template <class Buff, class Traits>
inline cb_iterator<Buff, Traits>
operator + (typename Traits::difference_type n, const cb_iterator<Buff, Traits>& it) {
    return it + n;
}

#if defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION) && !defined(BOOST_MSVC_STD_ITERATOR)

//! Iterator category.
template <class Buff, class Traits>
inline std::random_access_iterator_tag
iterator_category(const cb_iterator<Buff, Traits>&) {
    return std::random_access_iterator_tag();
}

//! The type of the elements stored in the circular buffer.
template <class Buff, class Traits>
inline typename Traits::value_type*
value_type(const cb_iterator<Buff, Traits>&) { return 0; }

//! Distance type.
template <class Buff, class Traits>
inline typename Traits::difference_type*
distance_type(const cb_iterator<Buff, Traits>&) { return 0; }

#endif // #if defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION) && !defined(BOOST_MSVC_STD_ITERATOR)

}; // namespace cb_details

/*!
    \class circular_buffer
    \brief Circular buffer - a STL compliant container.
    \param T The type of the elements stored in the circular buffer.
    \param Alloc The allocator type used for all internal memory management.
    \author <a href="mailto:jano_gaspar@yahoo.com">Jan Gaspar</a>
    \version 3.3
    \date 2003

    For more information how to use the circular buffer see the
    <a href="../circular_buffer.html">documentation</a>.
*/
template <class T, class Alloc>
class circular_buffer {

// Requirements
    BOOST_CLASS_REQUIRE(T, boost, AssignableConcept);

public:
// Basic types

    //! The type of the elements stored in the circular buffer.
    typedef typename Alloc::value_type value_type;

    //! Pointer to the element.
    typedef typename Alloc::pointer pointer;

    //! Const pointer to the element.
    typedef typename Alloc::const_pointer const_pointer;

    //! Reference to the element.
    typedef typename Alloc::reference reference;

    //! Const reference to the element.
    typedef typename Alloc::const_reference const_reference;

    //! Size type.
    typedef typename Alloc::size_type size_type;

    //! Difference type.
    typedef typename Alloc::difference_type difference_type;

    //! The type of the allocator used in the circular buffer.
    typedef Alloc allocator_type;

    //! Return the allocator.
    /*!
        \return Allocator
    */
    allocator_type get_allocator() const { return m_alloc; }

// Helper types

    // Define a type that represents the "best" way to pass the value_type to a method.
    typedef typename call_traits<value_type>::param_type param_value_type;

// Iterators

    //! Const (random access) iterator used to iterate through a circular buffer.
    typedef cb_details::cb_iterator< circular_buffer<T, Alloc>, cb_details::cb_const_traits<Alloc> > const_iterator;

    //! Iterator (random access) used to iterate through a circular buffer.
    typedef cb_details::cb_iterator< circular_buffer<T, Alloc>, cb_details::cb_nonconst_traits<Alloc> > iterator;

#if BOOST_VERSION >= 103100
    //! Const iterator used to iterate backwards through a circular buffer.
    typedef boost::reverse_iterator<const_iterator> const_reverse_iterator;

    //! Iterator used to iterate backwards through a circular buffer.
    typedef boost::reverse_iterator<iterator> reverse_iterator;
#else 
    //! Const iterator used to iterate backwards through a circular buffer.
    typedef typename reverse_iterator_generator<const_iterator>::type const_reverse_iterator;

    //! Iterator used to iterate backwards through a circular buffer.
    typedef typename reverse_iterator_generator<iterator>::type reverse_iterator;
#endif

private:
// Member variables

    //! The internal buffer used for storing elements in the circular buffer.
    pointer m_buff;

    //! The internal buffer's end (end of the storage space).
    pointer m_end;

    //! The virtual beginning of the circular buffer (the leftmost element).
    pointer m_first;

    //! The virtual end of the circular buffer (the rightmost element).
    pointer m_last;

    //! The number of items currently stored in the circular buffer.
    size_type m_size;

    //! The allocator.
    allocator_type m_alloc;

// Friends
#if defined(BOOST_NO_MEMBER_TEMPLATE_FRIENDS)
    friend iterator;
    friend const_iterator;
#else
    friend struct cb_details::cb_iterator< circular_buffer<T, Alloc>, cb_details::cb_const_traits<Alloc> >;
    friend struct cb_details::cb_iterator< circular_buffer<T, Alloc>, cb_details::cb_nonconst_traits<Alloc> >;
#endif

public:
// Element access

    //! Return an iterator pointing to the beginning of the circular buffer.
    iterator begin() { return iterator(this, empty() ? 0 : m_first); }

    //! Return an iterator pointing to the end of the circular buffer.
    iterator end() { return iterator(this, 0); }

    //! Return a const iterator pointing to the beginning of the circular buffer.
    const_iterator begin() const { return const_iterator(this, empty() ? 0 : m_first); }

    //! Return a const iterator pointing to the end of the circular buffer.
    const_iterator end() const { return const_iterator(this, 0); }

    //! Return a reverse iterator pointing to the beginning of the reversed circular buffer.
    reverse_iterator rbegin() { return reverse_iterator(end()); }

    //! Return a reverse iterator pointing to the end of the reversed circular buffer.
    reverse_iterator rend() { return reverse_iterator(begin()); }
    
    //! Return a const reverse iterator pointing to the beginning of the reversed circular buffer.
    const_reverse_iterator rbegin() const { return const_reverse_iterator(end()); }

    //! Return a const reverse iterator pointing to the end of the reversed circular buffer.
    const_reverse_iterator rend() const { return const_reverse_iterator(begin()); }

    //! Return the element at the <tt>index</tt> position.
    reference operator [] (size_type index) { return *add(m_first, index); }

    //! Return the element at the <tt>index</tt> position.
    const_reference operator [] (size_type index) const { return *add(m_first, index); }

    //! Return the element at the <tt>index</tt> position.
    /*!
        \throws std::out_of_range thrown when the <tt>index</tt> is invalid.
    */
    reference at(size_type index) {
        check_position(index);
        return (*this)[index];
    }

    //! Return the element at the <tt>index</tt> position.
    /*!
        \throws std::out_of_range thrown when the <tt>index</tt> is invalid.
    */
    const_reference at(size_type index) const {
        check_position(index);
        return (*this)[index];
    }

    //! Return the first (leftmost) element.
    reference front() { return *m_first; }

    //! Return the last (rightmost) element.
    reference back() { return *((m_last == m_buff ? m_end : m_last) - 1); }

    //! Return the first (leftmost) element.
    const_reference front() const { return *m_first; }

    //! Return the last (rightmost) element.
    const_reference back() const { return *((m_last == m_buff ? m_end : m_last) - 1); }

    //! Return pointer to data stored in the circular buffer as a continuous array of values.
    /*!
        This method can be usefull e.g. when passing the stored data into the legacy C API.
        \post <tt>\&(*this)[0] \< \&(*this)[1] \< ... \< \&(*this).back()</tt>
        \note For iterator invalidation see the <a href="../circular_buffer.html#invalidation">documentation</a>.
    */
    pointer data() {
        if (m_first < m_last || m_first == m_buff)
            return m_first;
        size_type constructed = 0;
        pointer src = m_first;
        pointer dest = m_buff;
        BOOST_CB_TRY
        for (pointer first = m_first; dest < src; src = first) {
            for (size_type ii = 0; src < m_end; ++src, ++dest, ++ii) {
                if (dest == first) {
                    first += ii;
                    break;
                }
                if (is_uninitialized(dest)) {
                    m_alloc.construct(dest, *src);
                    ++constructed;
                } else {
                    std::swap(*dest, *src);
                }
            }
        }
        BOOST_CB_UNWIND(
            for (dest = m_last; constructed > 0; ++dest, --constructed)
                    m_alloc.destroy(dest);
        )
        for (dest = m_buff + size(); dest < m_end; ++dest)
            m_alloc.destroy(dest);
        m_first = m_buff;
        m_last = add(m_buff, size());
        return m_buff;
    }

// Size and capacity

    //! Return the number of elements currently stored in the circular buffer.
    size_type size() const { return m_size; }

    //! Return the largest possible size (or capacity) of the circular buffer.
    size_type max_size() const { return m_alloc.max_size(); }
    
    //! Is the circular buffer empty?
    /*!
        \return true if there are no elements stored in the circular buffer.
        \return false otherwise.
    */
    bool empty() const { return size() == 0; }

    //! Is the circular buffer full?
    /*!
        \return true if the number of elements stored in the circular buffer
                equals the capacity of the circular buffer.
        \return false otherwise.
    */
    bool full() const { return size() == capacity(); }

    //! Return the capacity of the circular buffer.
    size_type capacity() const { return m_end - m_buff; }

    //! Change the capacity of the circular buffer.
    /*!
        \post <tt>(*this).capacity() == new_capacity</tt><br>
              If the current number of elements stored in the circular
              buffer is greater than the desired new capacity then the
              first (leftmost) <tt>((*this).size() - new_capacity)</tt> elements
              will be removed.
        \throws "An allocation error" if memory is exhausted (<tt>std::bad_alloc</tt> if standard allocator is used).
        \throws Whatever T::T(const T&) throws.
        \note For iterator invalidation see the <a href="../circular_buffer.html#invalidation">documentation</a>.
    */
    void set_capacity(size_type new_capacity) {
        if (new_capacity == capacity())
            return;
        pointer buff = allocate(new_capacity);
        size_type new_size = new_capacity < size() ? new_capacity : size();
        BOOST_CB_TRY
        std::uninitialized_copy(end() - new_size, end(), buff);
        BOOST_CB_UNWIND(deallocate(buff, new_capacity))
        destroy();
        m_size = new_size;
        m_buff = m_first = buff;
        m_end = m_buff + new_capacity;
        m_last = add(m_buff, size());
    }

    //! Change the size of the circular buffer.
    /*!
        \post <tt>(*this).size() == new_size</tt><br>
              If the new size is greater than the current size, the rest
              of the circular buffer is filled with copies of <tt>item</tt>.
              In case the resulting size exceeds the current capacity
              the capacity is set to <tt>new_size</tt>.
              If the new size is lower than the current size, the first
              (leftmost) <tt>((*this).size() - new_size)</tt> elements will be removed.
        \throws "An allocation error" if memory is exhausted (<tt>std::bad_alloc</tt> if standard allocator is used).
        \throws Whatever T::T(const T&) throws.
        \note For iterator invalidation see the <a href="../circular_buffer.html#invalidation">documentation</a>.
    */
    void resize(size_type new_size, param_value_type item = T()) {
        if (new_size > size()) {
            if (new_size > capacity())
                set_capacity(new_size);
            insert(end(), new_size - size(), item);
        } else {
            erase(begin(), end() - new_size);
        }
    }

// Construction/Destruction

    //! Create an empty circular buffer with a given capacity.
    /*!
        \post <tt>(*this).capacity() == capacity \&\& (*this).size == 0</tt>
        \throws "An allocation error" if memory is exhausted (<tt>std::bad_alloc</tt> if standard allocator is used).
    */
    explicit circular_buffer(
        size_type capacity,
        const allocator_type& a = allocator_type())
    : m_size(0), m_alloc(a) {
        m_first = m_last = m_buff = allocate(capacity);
        m_end = m_buff + capacity;
    }

    //! Create a full circular buffer with a given capacity and filled with copies of <tt>item</tt>.
    /*!
        \post <tt>(*this).size() == capacity \&\& (*this)[0] == (*this)[1] == ... == (*this).back() == item</tt>
        \throws "An allocation error" if memory is exhausted (<tt>std::bad_alloc</tt> if standard allocator is used).
        \throws Whatever T::T(const T&) throws.
    */
    circular_buffer(
        size_type capacity,
        param_value_type item,
        const allocator_type& a = allocator_type())
    : m_size(capacity), m_alloc(a) {
        m_first = m_last = m_buff = allocate(capacity);
        m_end = m_buff + capacity;
        BOOST_CB_TRY
        std::uninitialized_fill_n(m_buff, size(), item);
        BOOST_CB_UNWIND(deallocate(m_buff, capacity))
    }

    //! Copy constructor.
    /*!
        \post <tt>*this == cb</tt>
        \throws "An allocation error" if memory is exhausted (<tt>std::bad_alloc</tt> if standard allocator is used).
        \throws Whatever T::T(const T&) throws.
    */
    circular_buffer(const circular_buffer<T, Alloc>& cb)
    : m_size(cb.size()), m_alloc(cb.get_allocator()) {
        m_first = m_last = m_buff = allocate(cb.capacity());
        BOOST_CB_TRY
        m_end = std::uninitialized_copy(cb.begin(), cb.end(), m_buff);
        BOOST_CB_UNWIND(deallocate(m_buff, cb.capacity()))
    }

    //! Create a circular buffer with a copy of a range.
    /*!
        \post <tt>(*this).capacity() == capacity</tt><br>
              If the number of items to copy from the range
              <tt>[first, last)</tt> is greater than the specified
              <tt>capacity</tt> then only elements from the range
              <tt>[last - capacity, last)</tt> will be copied.
        \throws "An allocation error" if memory is exhausted (<tt>std::bad_alloc</tt> if standard allocator is used).
        \throws Whatever T::T(const T&) throws.
    */
    template <class InputIterator>
    circular_buffer(
        size_type capacity,
        InputIterator first,
        InputIterator last,
        const allocator_type& a = allocator_type())
    : m_alloc(a) {
        m_first = m_buff = allocate(capacity);
        m_end = m_buff + capacity;
        size_type diff = std::distance(first, last);
        if (diff > capacity) {
            std::advance(first, diff - capacity);
            m_size = capacity;
            m_last = m_buff;
        } else {
            m_size = diff;
            if (diff == capacity) 
                m_last = m_buff;
            else
                m_last = m_buff + size();
        }
        BOOST_CB_TRY
        std::uninitialized_copy(first, last, m_buff);
        BOOST_CB_UNWIND(deallocate(m_buff, capacity))
    }

    //! Destructor.
    ~circular_buffer() { destroy(); }

private:
// Helper functors

    // Functor for assigning n items.
    struct assign_n {
        size_type m_n;
        param_value_type m_item;
        assign_n(size_type n, param_value_type item) : m_n(n), m_item(item) {}
        void operator () (pointer p) const {
            std::uninitialized_fill_n(p, m_n, m_item);
        }
    private:
        assign_n& operator = (const assign_n&); // do not generate
    };

    // Functor for assigning range of items.
    template <class InputIterator>
    struct assign_range {
        InputIterator m_first;
        InputIterator m_last;
        assign_range(InputIterator first, InputIterator last) : m_first(first), m_last(last) {}
        void operator() (pointer p) const {
            std::uninitialized_copy(m_first, m_last, p);
        }
    };

public:
// Assign methods

    //! Assignment operator.
    /*!
        \post <tt>*this == cb</tt>
        \throws "An allocation error" if memory is exhausted (<tt>std::bad_alloc</tt> if standard allocator is used).
        \throws Whatever T::T(const T&) throws.
        \note For iterator invalidation see the <a href="../circular_buffer.html#invalidation">documentation</a>.
    */
    circular_buffer<T, Alloc>& operator = (const circular_buffer<T, Alloc>& cb) {
        if (this == &cb)
            return *this;
        pointer buff = allocate(cb.capacity());
        BOOST_CB_TRY
        pointer last = std::uninitialized_copy(cb.begin(), cb.end(), buff);
        destroy();
        m_size = cb.size();
        m_first = m_buff = buff;
        m_end = m_buff + cb.capacity();
        m_last = full() ? m_buff : last;
        BOOST_CB_UNWIND(deallocate(buff, cb.capacity()))
        return *this;
    }

    //! Assign <tt>n</tt> items into the circular buffer.
    /*!
        \post <tt>(*this).size() == n \&\&
              (*this)[0] == (*this)[1] == ... == (*this).back() == item</tt><br>
              If the number of items to be assigned exceeds
              the capacity of the circular buffer the capacity
              is increased to <tt>n</tt> otherwise it stays unchanged.
        \throws "An allocation error" if memory is exhausted (<tt>std::bad_alloc</tt> if standard allocator is used).
        \throws Whatever T::T(const T&) throws.
        \note For iterator invalidation see the <a href="../circular_buffer.html#invalidation">documentation</a>.
    */
    void assign(size_type n, param_value_type item) { do_assign(n, assign_n(n, item)); }
    
    //! Assign a copy of range.
    /*!
        \post <tt>(*this).size() == std::distance(first, last)</tt><br>
              If the number of items to be assigned exceeds
              the capacity of the circular buffer the capacity
              is set to that number otherwise is stays unchanged.
        \throws "An allocation error" if memory is exhausted (<tt>std::bad_alloc</tt> if standard allocator is used).
        \throws Whatever T::T(const T&) throws.
        \note For iterator invalidation see the <a href="../circular_buffer.html#invalidation">documentation</a>.
    */
    template <class InputIterator>
    void assign(InputIterator first, InputIterator last) {
        assign(first, last, cb_details::cb_iterator_category_traits<InputIterator>::tag());
    }

    //! Swap the contents of two circular buffers.
    /*!
        \post <tt>this</tt> contains elements of <tt>cb</tt> and vice versa.
        \note For iterator invalidation see the <a href="../circular_buffer.html#invalidation">documentation</a>.
    */
    void swap(circular_buffer& cb) {
        std::swap(m_alloc, cb.m_alloc); // in general this is not necessary,
                                        // because allocators should not have state
        std::swap(m_buff, cb.m_buff);
        std::swap(m_end, cb.m_end);
        std::swap(m_first, cb.m_first);
        std::swap(m_last, cb.m_last);
        std::swap(m_size, cb.m_size);
    }

// push and pop

    //! Insert a new element at the end.
    /*!
        \post <tt>(*this).back() == item</tt><br>
              If the circular buffer is full, the first (leftmost) element will be removed.
        \throws Whatever T::T(const T&) throws.
        \throws Whatever T::operator = (const T&) throws.
        \note For iterator invalidation see the <a href="../circular_buffer.html#invalidation">documentation</a>.
    */
    void push_back(param_value_type item) {
        if (full()) {
            if (empty())
                return;
            *m_last = item;
            increment(m_first);
            m_last = m_first;
        } else {
            m_alloc.construct(m_last, item);
            increment(m_last);
            ++m_size;
        }
    }

    //! Insert a new element with the default value at the end.
    /*!
        \post <tt>(*this).back() == value_type()</tt><br>
              If the circular buffer is full, the first (leftmost) element will be removed.
        \throws Whatever T::T(const T&) throws.
        \throws Whatever T::operator = (const T&) throws.
        \note For iterator invalidation see the <a href="../circular_buffer.html#invalidation">documentation</a>.
    */
    void push_back() { push_back(value_type()); }

    //! Insert a new element at the start.
    /*!
        \post <tt>(*this).front() == item</tt><br>
              If the circular buffer is full, the last (rightmost) element will be removed.
        \throws Whatever T::T(const T&) throws.
        \throws Whatever T::operator = (const T&) throws.
        \note For iterator invalidation see the <a href="../circular_buffer.html#invalidation">documentation</a>.
    */
    void push_front(param_value_type item) {
        BOOST_CB_TRY
        if (full()) {
            if (empty())
                return;
            decrement(m_first);
            *m_first = item;
            m_last = m_first;
        } else {
            decrement(m_first);
            m_alloc.construct(m_first, item);
            ++m_size;
        }
        BOOST_CB_UNWIND(increment(m_first))
    }

    //! Insert a new element with the default value at the start.
    /*!
        \post <tt>(*this).front() == value_type()</tt><br>
              If the circular buffer is full, the last (rightmost) element will be removed.
        \throws Whatever T::T(const T&) throws.
        \throws Whatever T::operator = (const T&) throws.
        \note For iterator invalidation see the <a href="../circular_buffer.html#invalidation">documentation</a>.
    */
    void push_front() { push_front(value_type()); }

    //! Remove the last (rightmost) element.
    /*!
        \pre <tt>iterator it = (*this).end()</tt>
        \post <tt>(*this).end() != it</tt>
        \note For iterator invalidation see the <a href="../circular_buffer.html#invalidation">documentation</a>.
    */
    void pop_back() {
        decrement(m_last);
        m_alloc.destroy(m_last);
        --m_size;
    }

    //! Remove the first (leftmost) element.
    /*!
        \pre <tt>iterator it = (*this).begin()</tt>
        \post <tt>(*this).begin() != it</tt>
        \note For iterator invalidation see the <a href="../circular_buffer.html#invalidation">documentation</a>.
    */
    void pop_front() {
        m_alloc.destroy(m_first);
        increment(m_first);
        --m_size;
    }

private:
// Helper wrappers

    // Iterator dereference wrapper.
    template <class InputIterator>
    struct item_wrapper {
        mutable InputIterator m_it;
        item_wrapper(InputIterator it) : m_it(it) {}
        operator const_reference () const { return *m_it++; }
    };

public:
// Insert

    //! Insert the <tt>item</tt> before the given position.
    /*!
        \post The <tt>item</tt> will be inserted at the position <tt>pos</tt>.<br>
              If the circular buffer is full, the first (leftmost) element will be removed.
        \return iterator to the inserted element.
        \throws Whatever T::T(const T&) throws.
        \throws Whatever T::operator = (const T&) throws.
        \note For iterator invalidation see the <a href="../circular_buffer.html#invalidation">documentation</a>.
    */
    iterator insert(iterator pos, param_value_type item) {
        if (full() && pos == begin())
            return begin();
        if (pos.m_it == 0) {
            if (full())
                *m_last = item;
            else
                m_alloc.construct(m_last, item);
            pos.m_it = m_last;
        } else {
            pointer src = m_last;
            pointer dest = m_last;
            BOOST_CB_TRY
            while (src != pos.m_it) {
                decrement(src);
                create_copy(dest, *src);
                decrement(dest);
            }
            *pos = item;
            BOOST_CB_UNWIND(
                for (pointer it = m_last; it != dest; decrement(it))
                    destroy_copy(it);
            )
        }
        increment(m_last);
        if (full())
            increment(m_first);
        else
            ++m_size;
        return iterator(this, pos.m_it);
    }

    //! Insert a new element with the default value before the given position.
    /*!
        \post <tt>value_type()</tt> will be inserted at the position <tt>pos</tt>.<br>
              If the circular buffer is full, the first (leftmost) element will be removed.
        \return iterator to the inserted element.
        \throws Whatever T::T(const T&) throws.
        \throws Whatever T::operator = (const T&) throws.
        \note For iterator invalidation see the <a href="../circular_buffer.html#invalidation">documentation</a>.
    */
    iterator insert(iterator pos) { return insert(pos, value_type()); }

    //! Insert <tt>n</tt> copies of the item before the given position.
    /*!
        \post This operation preserves the capacity of the circular buffer.
              If the insertion would result in exceeding the capacity
              of the circular buffer then the necessary number of elements
              from the beginning (left) of the circular buffer will be removed
              or not all <tt>n</tt> elements will be inserted or both.<tt><br>
              Example:<br>
                original circular buffer |1|2|3|4| | | - capacity: 6, size: 4<br>
                position ---------------------^<br>
                insert(position, (size_t)5, 6);<br>
                (If the operation won't preserve capacity, the buffer
                would look like this |1|2|6|6|6|6|6|3|4|)<br>
                RESULTING circular buffer |6|6|6|6|3|4| - capacity: 6, size: 6</tt>
        \throws Whatever T::T(const T&) throws.
        \throws Whatever T::operator = (const T&) throws.
        \note For iterator invalidation see the <a href="../circular_buffer.html#invalidation">documentation</a>.
    */
    void insert(iterator pos, size_type n, param_value_type item) {
        if (n == 0)
            return;
        size_type copy = capacity() - (end() - pos);
        if (copy == 0)
            return;
        if (n > copy)
            n = copy;
        insert_n_item(pos, n, item);
    }

    //! Insert the range <tt>[first, last)</tt> before the given position.
    /*!
        \post This operation preserves the capacity of the circular buffer.
              If the insertion would result in exceeding the capacity
              of the circular buffer then the necessary number of elements
              from the beginning (left) of the circular buffer will be removed
              or not the whole range will be inserted or both.
              In case the whole range cannot be inserted it will be inserted just
              some elements from the end (right) of the range (see the example).<tt><br>
              Example:<br>
                array to insert: int array[] = { 5, 6, 7, 8, 9 };<br>
                original circular buffer |1|2|3|4| | | - capacity: 6, size: 4<br>
                position ---------------------^<br>
                insert(position, array, array + 5);<br>
                (If the operation won't preserve capacity, the buffer
                would look like this |1|2|5|6|7|8|9|3|4|)<br>
                RESULTING circular buffer |6|7|8|9|3|4| - capacity: 6, size: 6</tt>
        \throws Whatever T::T(const T&) throws.
        \throws Whatever T::operator = (const T&) throws.
        \note For iterator invalidation see the <a href="../circular_buffer.html#invalidation">documentation</a>.
    */
    template <class InputIterator>
    void insert(iterator pos, InputIterator first, InputIterator last) {
        insert(pos, first, last, cb_details::cb_iterator_category_traits<InputIterator>::tag());
    }

    //! Insert an <tt>item</tt> before the given position.
    /*!
        \post The <tt>item</tt> will be inserted at the position <tt>pos</tt>.<br>
              If the circular buffer is full, the last element (rightmost) will be removed.
        \return iterator to the inserted element.
        \throws Whatever T::T(const T&) throws.
        \throws Whatever T::operator = (const T&) throws.
        \note For iterator invalidation see the <a href="../circular_buffer.html#invalidation">documentation</a>.
    */
    iterator rinsert(iterator pos, param_value_type item) {
        if (full() && pos == end())
            return end();
        if (pos == begin()) {
            BOOST_CB_TRY
            decrement(m_first);
            if (full())
                *m_first = item;
            else
                m_alloc.construct(m_first, item);
            BOOST_CB_UNWIND(increment(m_first))
        } else {
            pointer src = m_first;
            pointer dest = m_first;
            pointer it = get_valid_pointer(pos.m_it);
            decrement(dest);
            BOOST_CB_TRY
            while (src != it) {
                create_copy(dest, *src);
                increment(src);
                increment(dest);
            }
            decrement(m_first);
            *--pos = item;
            BOOST_CB_UNWIND(
                it = m_first;
                for (increment(m_first); it != dest; increment(it))
                    destroy_copy(it);
            )
        }
        if (full())
            decrement(m_last);
        else
            ++m_size;
        return iterator(this, pos.m_it);
    }

    //! Insert a new element with the default value before the given position.
    /*!
        \post <tt>value_type()</tt> will be inserted at the position <tt>pos</tt>.<br>
              If the circular buffer is full, the last (rightmost) element will be removed.
        \return iterator to the inserted element.
        \throws Whatever T::T(const T&) throws.
        \throws Whatever T::operator = (const T&) throws.
        \note For iterator invalidation see the <a href="../circular_buffer.html#invalidation">documentation</a>.
    */
    iterator rinsert(iterator pos) { return rinsert(pos, value_type()); }

    //! Insert <tt>n</tt> copies of the item before the given position.
    /*!
        \post This operation preserves the capacity of the circular buffer.
              If the insertion would result in exceeding the capacity
              of the circular buffer then the necessary number of elements
              from the end (right) of the circular buffer will be removed
              or not all <tt>n</tt> elements will be inserted or both.<tt><br>
              Example:<br>
                original circular buffer |1|2|3|4| | | - capacity: 6, size: 4<br>
                position ---------------------^<br>
                insert(position, (size_t)5, 6);<br>
                (If the operation won't preserve capacity, the buffer
                would look like this |1|2|6|6|6|6|6|3|4|)<br>
                RESULTING circular buffer |1|2|6|6|6|6| - capacity: 6, size: 6</tt>
        \throws Whatever T::T(const T&) throws.
        \throws Whatever T::operator = (const T&) throws.
        \note For iterator invalidation see the <a href="../circular_buffer.html#invalidation">documentation</a>.
    */
    void rinsert(iterator pos, size_type n, param_value_type item) { rinsert_n_item(pos, n, item); }

    //! Insert the range <tt>[first, last)</tt> before the given position.
    /*!
        \post This operation preserves the capacity of the circular buffer.
              If the insertion would result in exceeding the capacity
              of the circular buffer then the necessary number of elements
              from the end (right) of the circular buffer will be removed
              or not the whole range will be inserted or both.
              In case the whole range cannot be inserted it will be inserted just
              some elements from the beginning (left) of the range (see the example).<tt><br>
              Example:<br>
                array to insert: int array[] = { 5, 6, 7, 8, 9 };<br>
                original circular buffer |1|2|3|4| | | - capacity: 6, size: 4<br>
                position ---------------------^<br>
                insert(position, array, array + 5);<br>
                (If the operation won't preserve capacity, the buffer
                would look like this |1|2|5|6|7|8|9|3|4|)<br>
                RESULTING circular buffer |1|2|5|6|7|8| - capacity: 6, size: 6</tt>
        \throws Whatever T::T(const T&) throws.
        \throws Whatever T::operator = (const T&) throws.
        \note For iterator invalidation see the <a href="../circular_buffer.html#invalidation">documentation</a>.
    */
    template <class InputIterator>
    void rinsert(iterator pos, InputIterator first, InputIterator last) {
        rinsert(pos, first, last, cb_details::cb_iterator_category_traits<InputIterator>::tag());
    }

// Erase

    //! Erase the element at the given position.
    /*!
        \pre <tt>size_type old_size = (*this).size()</tt>
        \post <tt>(*this).size() == old_size - 1</tt><br>
              Removes an element at the position <tt>pos</tt>.
        \return iterator to the first element remaining beyond the removed
                element or <tt>(*this).end()</tt> if no such element exists.
        \note For iterator invalidation see the <a href="../circular_buffer.html#invalidation">documentation</a>.
    */
    iterator erase(iterator pos) {
        std::copy(pos + 1, end(), pos);
        decrement(m_last);
        m_alloc.destroy(m_last);
        --m_size;
        return iterator(this, pos.m_it == m_last ? 0 : pos.m_it);
    }

    //! Erase the range <tt>[first, last)</tt>.
    /*!
        \pre <tt>size_type old_size = (*this).size()</tt>
        \post <tt>(*this).size() == old_size - std::distance(first, last)</tt><br>
              Removes the elements from the range <tt>[first, last)</tt>.
        \return iterator to the first element remaining beyond the removed
                element or <tt>(*this).end()</tt> if no such element exists.
        \note For iterator invalidation see the <a href="../circular_buffer.html#invalidation">documentation</a>.
    */
    iterator erase(iterator first, iterator last) {
        if (first != last)
            std::copy(last, end(), first);
        difference_type diff = last - first;
        m_size -= diff;
        for (; diff > 0; --diff) {
            decrement(m_last);
            m_alloc.destroy(m_last);
        }
        return iterator(this, first.m_it == m_last ? 0 : first.m_it);
    }

    //! Erase all the stored elements.
    /*!
        \post (*this).size() == 0
        \note For iterator invalidation see the <a href="../circular_buffer.html#invalidation">documentation</a>.
    */
    void clear() {
        destroy_content();
        m_first = m_last = m_buff;
        m_size = 0;
    }

private:
// Helper methods

    //! Check if the <tt>index</tt> is valid.
    void check_position(size_type index) const {
        if (index >= size())
            throw_exception(std::out_of_range("circular_buffer"));
    }

    //! Increment the pointer.
    template <class Pointer0>
    void increment(Pointer0& p) const {
        if (++p == m_end)
            p = m_buff;
    }

    //! Decrement the pointer.
    template <class Pointer0>
    void decrement(Pointer0& p) const {
        if (p == m_buff)
            p = m_end;
        --p;
    }

    //! Add <tt>n</tt> to the pointer.
    template <class Pointer0>
    Pointer0 add(Pointer0 p, difference_type n) const {
        return p + (n < (m_end - p) ? n : n - capacity());
    }

    //! Subtract <tt>n</tt> from the pointer.
    template <class Pointer0>
    Pointer0 sub(Pointer0 p, difference_type n) const {
        return p - (n > (p - m_buff) ? n - capacity() : n);
    }

    //! Return valid pointer.
    pointer get_valid_pointer(pointer p) const { return p == 0 ? m_last : p; }

    //! Does the pointer point to the uninitialized memory?
    bool is_uninitialized(pointer p) const { return p >= m_last && (m_first < m_last || p < m_first); }

    //! Create a copy of the <tt>item</tt> at the given position.
    /*!
        The copy is created either at uninitialized memory
        or replaces the old item.
    */
    void create_copy(pointer pos, param_value_type item) {
        if (is_uninitialized(pos))
            m_alloc.construct(pos, item);
        else
            *pos = item;
    }

    //! Try to recover when the create_copy fails.
    void destroy_copy(pointer pos) {
        if (is_uninitialized(pos))
            m_alloc.destroy(pos);
        // the assignment cannot be rolled back
    }

    //! Allocate memory.
    pointer allocate(size_type n) {
        if (n > max_size())
            throw_exception(std::length_error("circular_buffer"));
        return (n == 0) ? 0 : m_alloc.allocate(n, 0);
    }

    //! Deallocate memory.
    void deallocate(pointer p, size_type n) {
        if (p != 0)
            m_alloc.deallocate(p, n);
    }

    //! Destroy the content of the circular buffer.
    void destroy_content() {
        iterator last = end();
        for (iterator it = begin(); it != last; ++it)
            m_alloc.destroy(it.m_it);
    }

    //! Destroy content and frees allocated memory.
    void destroy() {
        destroy_content();
        deallocate(m_buff, capacity());
    }

    //! Helper assign method.
    template <class InputIterator>
    void assign(InputIterator n, InputIterator item, cb_details::cb_int_iterator_tag) {
        assign((size_type)n, item);
    }

    //! Helper assign method.
    template <class InputIterator>
    void assign(InputIterator first, InputIterator last, std::input_iterator_tag) {
        do_assign(std::distance(first, last), assign_range<InputIterator>(first, last));
    }

    //! Helper assign method.
    template <class Functor>
    void do_assign(size_type n, const Functor& fnc) {
        if (n > capacity()) {
            pointer buff = allocate(n);
            BOOST_CB_TRY
            fnc(buff);
            BOOST_CB_UNWIND(deallocate(buff, n))
            destroy();
            m_buff = buff;
            m_end = m_buff + n;
        } else {
            destroy_content();
            BOOST_CB_TRY
            fnc(m_buff);
            BOOST_CB_UNWIND(m_size = 0;)
        }
        m_size = n;
        m_first = m_buff;
        m_last = add(m_buff, size());
    }

    //! Helper insert method.
    template <class InputIterator>
    void insert(iterator pos, InputIterator n, InputIterator item, cb_details::cb_int_iterator_tag) {
        insert(pos, (size_type)n, item);
    }

    //! Helper insert method.
    template <class InputIterator>
    void insert(iterator pos, InputIterator first, InputIterator last, std::input_iterator_tag) {
        difference_type n = std::distance(first, last);
        if (n == 0)
            return;
        difference_type copy = capacity() - (end() - pos);
        if (copy == 0)
            return;
        if (n > copy) {
            std::advance(first, n - copy);
            n = copy;
        }
        insert_n_item(pos, n, item_wrapper<InputIterator>(first));
    }

    //! Helper insert method.
    template <class Item>
    void insert_n_item(iterator pos, size_type n, const Item& item) {
        size_type construct = capacity() - size();
        if (construct > n)
            construct = n;
        if (pos.m_it == 0) {
            size_type ii = 0;
            pointer p = m_last;
            BOOST_CB_TRY
            for (; ii < construct; ++ii, increment(p))
                m_alloc.construct(p, item);
            for (;ii < n; ++ii, increment(p))
                *p = item;
            BOOST_CB_UNWIND(
                size_type unwind = ii < construct ? ii : construct;
                for (ii = 0, p = m_last; ii < unwind; ++ii, increment(p))
                    m_alloc.destroy(p);
            )
        } else {
            pointer src = m_last;
            pointer dest = add(m_last, n - 1);
            pointer p = pos.m_it;
            size_type ii = 0;
            BOOST_CB_TRY
            while (src != p) {
                decrement(src);
                create_copy(dest, *src);
                decrement(dest);
            }
            for (; ii < n; ++ii, increment(p))
                create_copy(p, item);
            BOOST_CB_UNWIND(
                for (p = add(m_last, n - 1); p != dest; decrement(p))
                    destroy_copy(p);
                for (n = 0, p = pos.m_it; n < ii; ++n, increment(p))
                    destroy_copy(p);
            )
        }
        m_last = add(m_last, n);
        m_first = add(m_first, n - construct);
        m_size += construct;
    }

    //! Helper rinsert method.
    template <class InputIterator>
    void rinsert(iterator pos, InputIterator n, InputIterator item, cb_details::cb_int_iterator_tag) {
        rinsert(pos, (size_type)n, item);
    }

    //! Helper rinsert method.
    template <class InputIterator>
    void rinsert(iterator pos, InputIterator first, InputIterator last, std::input_iterator_tag) {
        rinsert_n_item(pos, std::distance(first, last), item_wrapper<InputIterator>(first));
    }

    //! Helper rinsert method.
    template <class Item>
    void rinsert_n_item(iterator pos, size_type n, const Item& item) {
        if (n == 0)
            return;
        size_type copy = capacity() - (pos - begin());
        if (copy == 0)
            return;
        if (n > copy)
            n = copy;
        size_type construct = capacity() - size();
        if (construct > n)
            construct = n;
        if (pos == begin()) {
            pointer p = sub(get_valid_pointer(pos.m_it), n);
            size_type ii = n;
            BOOST_CB_TRY
            for (;ii > construct; --ii, increment(p))
                *p = item;
            for (; ii > 0; --ii, increment(p))
                m_alloc.construct(p, item);
            BOOST_CB_UNWIND(
                size_type unwind = ii < construct ? construct - ii : 0;
                p = sub(get_valid_pointer(pos.m_it), construct);
                for (ii = 0; ii < unwind; ++ii, increment(p))
                    m_alloc.destroy(p);
            )
        } else {
            pointer src = m_first;
            pointer dest = sub(m_first, n);
            pointer p = get_valid_pointer(pos.m_it);
            size_type ii = 0;
            BOOST_CB_TRY
            while (src != p) {
                create_copy(dest, *src);
                increment(src);
                increment(dest);
            }
            p = sub(p, n);
            for (; ii < n; ++ii, increment(p))
                create_copy(p, item);
            BOOST_CB_UNWIND(
                for (p = sub(m_first, n); p != dest; increment(p))
                    destroy_copy(p);
                p = sub(get_valid_pointer(pos.m_it), n);
                for (n = 0; n < ii; ++n, increment(p))
                    destroy_copy(p);
            )
        }
        m_first = sub(m_first, n);
        m_last = sub(m_last, n - construct);
        m_size += construct;
    }
};

// Non-member functions

//! Test two circular buffers for equality.
template <class T, class Alloc>
inline bool operator == (const circular_buffer<T, Alloc>& lhs,
                         const circular_buffer<T, Alloc>& rhs) {
    return lhs.size() == rhs.size() &&
        std::equal(lhs.begin(), lhs.end(), rhs.begin());
}

//! Lexicographical comparison.
template <class T, class Alloc>
inline bool operator < (const circular_buffer<T, Alloc>& lhs,
                        const circular_buffer<T, Alloc>& rhs) {
    return std::lexicographical_compare(
        lhs.begin(), lhs.end(), rhs.begin(), rhs.end());
}

#if !defined(BOOST_NO_FUNCTION_TEMPLATE_ORDERING) || defined(BOOST_MSVC)

//! Test two circular buffers for non-equality.
template <class T, class Alloc>
inline bool operator != (const circular_buffer<T, Alloc>& lhs,
                         const circular_buffer<T, Alloc>& rhs) {
    return !(lhs == rhs);
}

//! Lexicographical comparison.
template <class T, class Alloc>
inline bool operator > (const circular_buffer<T, Alloc>& lhs,
                        const circular_buffer<T, Alloc>& rhs) {
    return rhs < lhs;
}

//! Lexicographical comparison.
template <class T, class Alloc>
inline bool operator <= (const circular_buffer<T, Alloc>& lhs,
                         const circular_buffer<T, Alloc>& rhs) {
    return !(rhs < lhs);
}

//! Lexicographical comparison.
template <class T, class Alloc>
inline bool operator >= (const circular_buffer<T, Alloc>& lhs,
                         const circular_buffer<T, Alloc>& rhs) {
    return !(lhs < rhs);
}

//! Swap the contents of two circular buffers.
template <class T, class Alloc>
inline void swap(circular_buffer<T, Alloc>& lhs, circular_buffer<T, Alloc>& rhs) {
    lhs.swap(rhs);
}

#endif // #if !defined(BOOST_NO_FUNCTION_TEMPLATE_ORDERING) || defined(BOOST_MSVC)

#undef BOOST_CB_UNWIND
#undef BOOST_CB_TRY

} // namespace boost

#endif // #if !defined(BOOST_CIRCULAR_BUFFER_BASE_HPP)