about summary refs log blame commit diff
path: root/absl/container/inlined_vector.h
blob: f68ca507414960ba0e04dd854c76174a29090ea1 (plain) (tree)
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





























































































































                                                                                







                                                                            


                                                             






                                                                                
















































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































































                                                                                
// Copyright 2017 The Abseil Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
// -----------------------------------------------------------------------------
// File: inlined_vector.h
// -----------------------------------------------------------------------------
//
// This header file contains the declaration and definition of an "inlined
// vector" which behaves in an equivalent fashion to a `std::vector`, except
// that storage for small sequences of the vector are provided inline without
// requiring any heap allocation.

// An `absl::InlinedVector<T,N>` specifies the size N at which to inline as one
// of its template parameters. Vectors of length <= N are provided inline.
// Typically N is very small (e.g., 4) so that sequences that are expected to be
// short do not require allocations.

// An `absl::InlinedVector` does not usually require a specific allocator; if
// the inlined vector grows beyond its initial constraints, it will need to
// allocate (as any normal `std::vector` would) and it will generally use the
// default allocator in that case; optionally, a custom allocator may be
// specified using an `absl::InlinedVector<T,N,A>` construction.

#ifndef ABSL_CONTAINER_INLINED_VECTOR_H_
#define ABSL_CONTAINER_INLINED_VECTOR_H_

#include <algorithm>
#include <cassert>
#include <cstddef>
#include <cstdlib>
#include <cstring>
#include <initializer_list>
#include <iterator>
#include <memory>
#include <type_traits>
#include <utility>

#include "absl/algorithm/algorithm.h"
#include "absl/base/internal/throw_delegate.h"
#include "absl/base/optimization.h"
#include "absl/base/port.h"
#include "absl/memory/memory.h"

namespace absl {

// -----------------------------------------------------------------------------
// InlinedVector
// -----------------------------------------------------------------------------
//
// An `absl::InlinedVector` is designed to be a drop-in replacement for
// `std::vector` for use cases where the vector's size is sufficiently small
// that it can be inlined. If the inlined vector does grow beyond its estimated
// size, it will trigger an initial allocation on the heap, and will behave as a
// `std:vector`. The API of the `absl::InlinedVector` within this file is
// designed to cover the same API footprint as covered by `std::vector`.
template <typename T, size_t N, typename A = std::allocator<T> >
class InlinedVector {
  using AllocatorTraits = std::allocator_traits<A>;

 public:
  using allocator_type = A;
  using value_type = typename allocator_type::value_type;
  using pointer = typename allocator_type::pointer;
  using const_pointer = typename allocator_type::const_pointer;
  using reference = typename allocator_type::reference;
  using const_reference = typename allocator_type::const_reference;
  using size_type = typename allocator_type::size_type;
  using difference_type = typename allocator_type::difference_type;
  using iterator = pointer;
  using const_iterator = const_pointer;
  using reverse_iterator = std::reverse_iterator<iterator>;
  using const_reverse_iterator = std::reverse_iterator<const_iterator>;

  InlinedVector() noexcept(noexcept(allocator_type()))
      : allocator_and_tag_(allocator_type()) {}

  explicit InlinedVector(const allocator_type& alloc) noexcept
      : allocator_and_tag_(alloc) {}

  // Create a vector with n copies of value_type().
  explicit InlinedVector(size_type n) : allocator_and_tag_(allocator_type()) {
    InitAssign(n);
  }

  // Create a vector with n copies of elem
  InlinedVector(size_type n, const value_type& elem,
                const allocator_type& alloc = allocator_type())
      : allocator_and_tag_(alloc) {
    InitAssign(n, elem);
  }

  // Create and initialize with the elements [first .. last).
  // The unused enable_if argument restricts this constructor so that it is
  // elided when value_type is an integral type.  This prevents ambiguous
  // interpretation between a call to this constructor with two integral
  // arguments and a call to the preceding (n, elem) constructor.
  template <typename InputIterator>
  InlinedVector(
      InputIterator first, InputIterator last,
      const allocator_type& alloc = allocator_type(),
      typename std::enable_if<!std::is_integral<InputIterator>::value>::type* =
          nullptr)
      : allocator_and_tag_(alloc) {
    AppendRange(first, last);
  }

  InlinedVector(std::initializer_list<value_type> init,
                const allocator_type& alloc = allocator_type())
      : allocator_and_tag_(alloc) {
    AppendRange(init.begin(), init.end());
  }

  InlinedVector(const InlinedVector& v);
  InlinedVector(const InlinedVector& v, const allocator_type& alloc);

  // This move constructor does not allocate and only moves the underlying
  // objects, so its `noexcept` specification depends on whether moving the
  // underlying objects can throw or not. We assume
  //  a) move constructors should only throw due to allocation failure and
  //  b) if `value_type`'s move constructor allocates, it uses the same
  //     allocation function as the `InlinedVector`'s allocator, so the move
  //     constructor is non-throwing if the allocator is non-throwing or
  //     `value_type`'s move constructor is specified as `noexcept`.
  InlinedVector(InlinedVector&& v) noexcept(
      absl::allocator_is_nothrow<allocator_type>::value ||
      std::is_nothrow_move_constructible<value_type>::value);

  // This move constructor allocates and also moves the underlying objects, so
  // its `noexcept` specification depends on whether the allocation can throw
  // and whether moving the underlying objects can throw. Based on the same
  // assumptions above, the `noexcept` specification is dominated by whether the
  // allocation can throw regardless of whether `value_type`'s move constructor
  // is specified as `noexcept`.
  InlinedVector(InlinedVector&& v, const allocator_type& alloc) noexcept(
      absl::allocator_is_nothrow<allocator_type>::value);

  ~InlinedVector() { clear(); }

  InlinedVector& operator=(const InlinedVector& v) {
    // Optimized to avoid reallocation.
    // Prefer reassignment to copy construction for elements.
    if (size() < v.size()) {  // grow
      reserve(v.size());
      std::copy(v.begin(), v.begin() + size(), begin());
      std::copy(v.begin() + size(), v.end(), std::back_inserter(*this));
    } else {  // maybe shrink
      erase(begin() + v.size(), end());
      std::copy(v.begin(), v.end(), begin());
    }
    return *this;
  }

  InlinedVector& operator=(InlinedVector&& v) {
    if (this == &v) {
      return *this;
    }
    if (v.allocated()) {
      clear();
      tag().set_allocated_size(v.size());
      init_allocation(v.allocation());
      v.tag() = Tag();
    } else {
      if (allocated()) clear();
      // Both are inlined now.
      if (size() < v.size()) {
        auto mid = std::make_move_iterator(v.begin() + size());
        std::copy(std::make_move_iterator(v.begin()), mid, begin());
        UninitializedCopy(mid, std::make_move_iterator(v.end()), end());
      } else {
        auto new_end = std::copy(std::make_move_iterator(v.begin()),
                                 std::make_move_iterator(v.end()), begin());
        Destroy(new_end, end());
      }
      tag().set_inline_size(v.size());
    }
    return *this;
  }

  InlinedVector& operator=(std::initializer_list<value_type> init) {
    AssignRange(init.begin(), init.end());
    return *this;
  }

  // InlinedVector::assign()
  //
  // Replaces the contents of the inlined vector with copies of those in the
  // iterator range [first, last).
  template <typename InputIterator>
  void assign(
      InputIterator first, InputIterator last,
      typename std::enable_if<!std::is_integral<InputIterator>::value>::type* =
          nullptr) {
    AssignRange(first, last);
  }

  // Overload of `InlinedVector::assign()` to take values from elements of an
  // initializer list
  void assign(std::initializer_list<value_type> init) {
    AssignRange(init.begin(), init.end());
  }

  // Overload of `InlinedVector::assign()` to replace the first `n` elements of
  // the inlined vector with `elem` values.
  void assign(size_type n, const value_type& elem) {
    if (n <= size()) {  // Possibly shrink
      std::fill_n(begin(), n, elem);
      erase(begin() + n, end());
      return;
    }
    // Grow
    reserve(n);
    std::fill_n(begin(), size(), elem);
    if (allocated()) {
      UninitializedFill(allocated_space() + size(), allocated_space() + n,
                        elem);
      tag().set_allocated_size(n);
    } else {
      UninitializedFill(inlined_space() + size(), inlined_space() + n, elem);
      tag().set_inline_size(n);
    }
  }

  // InlinedVector::size()
  //
  // Returns the number of elements in the inlined vector.
  size_type size() const noexcept { return tag().size(); }

  // InlinedVector::empty()
  //
  // Checks if the inlined vector has no elements.
  bool empty() const noexcept { return (size() == 0); }

  // InlinedVector::capacity()
  //
  // Returns the number of elements that can be stored in an inlined vector
  // without requiring a reallocation of underlying memory. Note that for
  // most inlined vectors, `capacity()` should equal its initial size `N`; for
  // inlined vectors which exceed this capacity, they will no longer be inlined,
  // and `capacity()` will equal its capacity on the allocated heap.
  size_type capacity() const noexcept {
    return allocated() ? allocation().capacity() : N;
  }

  // InlinedVector::max_size()
  //
  // Returns the maximum number of elements the vector can hold.
  size_type max_size() const noexcept {
    // One bit of the size storage is used to indicate whether the inlined
    // vector is allocated; as a result, the maximum size of the container that
    // we can express is half of the max for our size type.
    return std::numeric_limits<size_type>::max() / 2;
  }

  // InlinedVector::data()
  //
  // Returns a const T* pointer to elements of the inlined vector. This pointer
  // can be used to access (but not modify) the contained elements.
  // Only results within the range `[0,size())` are defined.
  const_pointer data() const noexcept {
    return allocated() ? allocated_space() : inlined_space();
  }

  // Overload of InlinedVector::data() to return a T* pointer to elements of the
  // inlined vector. This pointer can be used to access and modify the contained
  // elements.
  pointer data() noexcept {
    return allocated() ? allocated_space() : inlined_space();
  }

  // InlinedVector::clear()
  //
  // Removes all elements from the inlined vector.
  void clear() noexcept {
    size_type s = size();
    if (allocated()) {
      Destroy(allocated_space(), allocated_space() + s);
      allocation().Dealloc(allocator());
    } else if (s != 0) {  // do nothing for empty vectors
      Destroy(inlined_space(), inlined_space() + s);
    }
    tag() = Tag();
  }

  // InlinedVector::at()
  //
  // Returns the ith element of an inlined vector.
  const value_type& at(size_type i) const {
    if (ABSL_PREDICT_FALSE(i >= size())) {
      base_internal::ThrowStdOutOfRange(
          "InlinedVector::at failed bounds check");
    }
    return data()[i];
  }

  // InlinedVector::operator[]
  //
  // Returns the ith element of an inlined vector using the array operator.
  const value_type& operator[](size_type i) const {
    assert(i < size());
    return data()[i];
  }

  // Overload of InlinedVector::at() to return the ith element of an inlined
  // vector.
  value_type& at(size_type i) {
    if (i >= size()) {
      base_internal::ThrowStdOutOfRange(
          "InlinedVector::at failed bounds check");
    }
    return data()[i];
  }

  // Overload of InlinedVector::operator[] to return the ith element of an
  // inlined vector.
  value_type& operator[](size_type i) {
    assert(i < size());
    return data()[i];
  }

  // InlinedVector::back()
  //
  // Returns a reference to the last element of an inlined vector.
  value_type& back() {
    assert(!empty());
    return at(size() - 1);
  }

  // Overload of InlinedVector::back() returns a reference to the last element
  // of an inlined vector of const values.
  const value_type& back() const {
    assert(!empty());
    return at(size() - 1);
  }

  // InlinedVector::front()
  //
  // Returns a reference to the first element of an inlined vector.
  value_type& front() {
    assert(!empty());
    return at(0);
  }

  // Overload of InlinedVector::front() returns a reference to the first element
  // of an inlined vector of const values.
  const value_type& front() const {
    assert(!empty());
    return at(0);
  }

  // InlinedVector::emplace_back()
  //
  // Constructs and appends an object to the inlined vector.
  template <typename... Args>
  void emplace_back(Args&&... args) {
    size_type s = size();
    assert(s <= capacity());
    if (ABSL_PREDICT_FALSE(s == capacity())) {
      GrowAndEmplaceBack(std::forward<Args>(args)...);
      return;
    }
    assert(s < capacity());

    value_type* space;
    if (allocated()) {
      tag().set_allocated_size(s + 1);
      space = allocated_space();
    } else {
      tag().set_inline_size(s + 1);
      space = inlined_space();
    }
    Construct(space + s, std::forward<Args>(args)...);
  }

  // InlinedVector::push_back()
  //
  // Appends a const element to the inlined vector.
  void push_back(const value_type& t) { emplace_back(t); }

  // Overload of InlinedVector::push_back() to append a move-only element to the
  // inlined vector.
  void push_back(value_type&& t) { emplace_back(std::move(t)); }

  // InlinedVector::pop_back()
  //
  // Removes the last element (which is destroyed) in the inlined vector.
  void pop_back() {
    assert(!empty());
    size_type s = size();
    if (allocated()) {
      Destroy(allocated_space() + s - 1, allocated_space() + s);
      tag().set_allocated_size(s - 1);
    } else {
      Destroy(inlined_space() + s - 1, inlined_space() + s);
      tag().set_inline_size(s - 1);
    }
  }

  // InlinedVector::resize()
  //
  // Resizes the inlined vector to contain `n` elements. If `n` is smaller than
  // the inlined vector's current size, extra elements are destroyed. If `n` is
  // larger than the initial size, new elements are value-initialized.
  void resize(size_type n);

  // Overload of InlinedVector::resize() to resize the inlined vector to contain
  // `n` elements. If `n` is larger than the current size, enough copies of
  // `elem` are appended to increase its size to `n`.
  void resize(size_type n, const value_type& elem);

  // InlinedVector::begin()
  //
  // Returns an iterator to the beginning of the inlined vector.
  iterator begin() noexcept { return data(); }

  // Overload of InlinedVector::begin() for returning a const iterator to the
  // beginning of the inlined vector.
  const_iterator begin() const noexcept { return data(); }

  // InlinedVector::cbegin()
  //
  // Returns a const iterator to the beginning of the inlined vector.
  const_iterator cbegin() const noexcept { return begin(); }

  // InlinedVector::end()
  //
  // Returns an iterator to the end of the inlined vector.
  iterator end() noexcept { return data() + size(); }

  // Overload of InlinedVector::end() for returning a const iterator to the end
  // of the inlined vector.
  const_iterator end() const noexcept { return data() + size(); }

  // InlinedVector::cend()
  //
  // Returns a const iterator to the end of the inlined vector.
  const_iterator cend() const noexcept { return end(); }

  // InlinedVector::rbegin()
  //
  // Returns a reverse iterator from the end of the inlined vector.
  reverse_iterator rbegin() noexcept { return reverse_iterator(end()); }

  // Overload of InlinedVector::rbegin() for returning a const reverse iterator
  // from the end of the inlined vector.
  const_reverse_iterator rbegin() const noexcept {
    return const_reverse_iterator(end());
  }

  // InlinedVector::crbegin()
  //
  // Returns a const reverse iterator from the end of the inlined vector.
  const_reverse_iterator crbegin() const noexcept { return rbegin(); }

  // InlinedVector::rend()
  //
  // Returns a reverse iterator from the beginning of the inlined vector.
  reverse_iterator rend() noexcept { return reverse_iterator(begin()); }

  // Overload of InlinedVector::rend() for returning a const reverse iterator
  // from the beginning of the inlined vector.
  const_reverse_iterator rend() const noexcept {
    return const_reverse_iterator(begin());
  }

  // InlinedVector::crend()
  //
  // Returns a reverse iterator from the beginning of the inlined vector.
  const_reverse_iterator crend() const noexcept { return rend(); }

  // InlinedVector::emplace()
  //
  // Constructs and inserts an object to the inlined vector at the given
  // `position`, returning an iterator pointing to the newly emplaced element.
  template <typename... Args>
  iterator emplace(const_iterator position, Args&&... args);

  // InlinedVector::insert()
  //
  // Inserts an element of the specified value at `position`, returning an
  // iterator pointing to the newly inserted element.
  iterator insert(const_iterator position, const value_type& v) {
    return emplace(position, v);
  }

  // Overload of InlinedVector::insert() for inserting an element of the
  // specified rvalue, returning an iterator pointing to the newly inserted
  // element.
  iterator insert(const_iterator position, value_type&& v) {
    return emplace(position, std::move(v));
  }

  // Overload of InlinedVector::insert() for inserting `n` elements of the
  // specified value at `position`, returning an iterator pointing to the first
  // of the newly inserted elements.
  iterator insert(const_iterator position, size_type n, const value_type& v) {
    return InsertWithCount(position, n, v);
  }

  // Overload of `InlinedVector::insert()` to disambiguate the two
  // three-argument overloads of `insert()`, returning an iterator pointing to
  // the first of the newly inserted elements.
  template <typename InputIterator,
            typename = typename std::enable_if<std::is_convertible<
                typename std::iterator_traits<InputIterator>::iterator_category,
                std::input_iterator_tag>::value>::type>
  iterator insert(const_iterator position, InputIterator first,
                  InputIterator last) {
    using IterType =
        typename std::iterator_traits<InputIterator>::iterator_category;
    return InsertWithRange(position, first, last, IterType());
  }

  // Overload of InlinedVector::insert() for inserting a list of elements at
  // `position`, returning an iterator pointing to the first of the newly
  // inserted elements.
  iterator insert(const_iterator position,
                  std::initializer_list<value_type> init) {
    return insert(position, init.begin(), init.end());
  }

  // InlinedVector::erase()
  //
  // Erases the element at `position` of the inlined vector, returning an
  // iterator pointing to the following element or the container's end if the
  // last element was erased.
  iterator erase(const_iterator position) {
    assert(position >= begin());
    assert(position < end());

    iterator pos = const_cast<iterator>(position);
    std::move(pos + 1, end(), pos);
    pop_back();
    return pos;
  }

  // Overload of InlinedVector::erase() for erasing all elements in the
  // iteraror range [first, last) in the inlined vector, returning an iterator
  // pointing to the first element following the range erased, or the
  // container's end if range included the container's last element.
  iterator erase(const_iterator first, const_iterator last);

  // InlinedVector::reserve()
  //
  // Enlarges the underlying representation of the inlined vector so it can hold
  // at least `n` elements. This method does not change `size()` or the actual
  // contents of the vector.
  //
  // Note that if `n` does not exceed the inlined vector's initial size `N`,
  // `reserve()` will have no effect; if it does exceed its initial size,
  // `reserve()` will trigger an initial allocation and move the inlined vector
  // onto the heap. If the vector already exists on the heap and the requested
  // size exceeds it, a reallocation will be performed.
  void reserve(size_type n) {
    if (n > capacity()) {
      // Make room for new elements
      EnlargeBy(n - size());
    }
  }

  // InlinedVector::swap()
  //
  // Swaps the contents of this inlined vector with the contents of `other`.
  void swap(InlinedVector& other);

  // InlinedVector::get_allocator()
  //
  // Returns the allocator of this inlined vector.
  allocator_type get_allocator() const { return allocator(); }

 private:
  static_assert(N > 0, "inlined vector with nonpositive size");

  // It holds whether the vector is allocated or not in the lowest bit.
  // The size is held in the high bits:
  //   size_ = (size << 1) | is_allocated;
  class Tag {
   public:
    Tag() : size_(0) {}
    size_type size() const { return size_ >> 1; }
    void add_size(size_type n) { size_ += n << 1; }
    void set_inline_size(size_type n) { size_ = n << 1; }
    void set_allocated_size(size_type n) { size_ = (n << 1) | 1; }
    bool allocated() const { return size_ & 1; }

   private:
    size_type size_;
  };

  // Derives from allocator_type to use the empty base class optimization.
  // If the allocator_type is stateless, we can 'store'
  // our instance of it for free.
  class AllocatorAndTag : private allocator_type {
   public:
    explicit AllocatorAndTag(const allocator_type& a, Tag t = Tag())
        : allocator_type(a), tag_(t) {
    }
    Tag& tag() { return tag_; }
    const Tag& tag() const { return tag_; }
    allocator_type& allocator() { return *this; }
    const allocator_type& allocator() const { return *this; }
   private:
    Tag tag_;
  };

  class Allocation {
   public:
    Allocation(allocator_type& a,  // NOLINT(runtime/references)
               size_type capacity)
        : capacity_(capacity),
          buffer_(AllocatorTraits::allocate(a, capacity_)) {}

    void Dealloc(allocator_type& a) {  // NOLINT(runtime/references)
      AllocatorTraits::deallocate(a, buffer(), capacity());
    }

    size_type capacity() const { return capacity_; }
    const value_type* buffer() const { return buffer_; }
    value_type* buffer() { return buffer_; }

   private:
    size_type capacity_;
    value_type* buffer_;
  };

  const Tag& tag() const { return allocator_and_tag_.tag(); }
  Tag& tag() { return allocator_and_tag_.tag(); }

  Allocation& allocation() {
    return reinterpret_cast<Allocation&>(rep_.allocation_storage.allocation);
  }
  const Allocation& allocation() const {
    return reinterpret_cast<const Allocation&>(
        rep_.allocation_storage.allocation);
  }
  void init_allocation(const Allocation& allocation) {
    new (&rep_.allocation_storage.allocation) Allocation(allocation);
  }

  value_type* inlined_space() {
    return reinterpret_cast<value_type*>(&rep_.inlined_storage.inlined);
  }
  const value_type* inlined_space() const {
    return reinterpret_cast<const value_type*>(&rep_.inlined_storage.inlined);
  }

  value_type* allocated_space() {
    return allocation().buffer();
  }
  const value_type* allocated_space() const {
    return allocation().buffer();
  }

  const allocator_type& allocator() const {
    return allocator_and_tag_.allocator();
  }
  allocator_type& allocator() {
    return allocator_and_tag_.allocator();
  }

  bool allocated() const { return tag().allocated(); }

  // Enlarge the underlying representation so we can store size_ + delta elems.
  // The size is not changed, and any newly added memory is not initialized.
  void EnlargeBy(size_type delta);

  // Shift all elements from position to end() n places to the right.
  // If the vector needs to be enlarged, memory will be allocated.
  // Returns iterators pointing to the start of the previously-initialized
  // portion and the start of the uninitialized portion of the created gap.
  // The number of initialized spots is pair.second - pair.first;
  // the number of raw spots is n - (pair.second - pair.first).
  std::pair<iterator, iterator> ShiftRight(const_iterator position,
                                           size_type n);

  void ResetAllocation(Allocation new_allocation, size_type new_size) {
    if (allocated()) {
      Destroy(allocated_space(), allocated_space() + size());
      assert(begin() == allocated_space());
      allocation().Dealloc(allocator());
      allocation() = new_allocation;
    } else {
      Destroy(inlined_space(), inlined_space() + size());
      init_allocation(new_allocation);  // bug: only init once
    }
    tag().set_allocated_size(new_size);
  }

  template <typename... Args>
  void GrowAndEmplaceBack(Args&&... args) {
    assert(size() == capacity());
    const size_type s = size();

    Allocation new_allocation(allocator(), 2 * capacity());

    Construct(new_allocation.buffer() + s, std::forward<Args>(args)...);
    UninitializedCopy(std::make_move_iterator(data()),
                      std::make_move_iterator(data() + s),
                      new_allocation.buffer());

    ResetAllocation(new_allocation, s + 1);
  }

  void InitAssign(size_type n);
  void InitAssign(size_type n, const value_type& t);

  template <typename... Args>
  void Construct(pointer p, Args&&... args) {
    AllocatorTraits::construct(allocator(), p, std::forward<Args>(args)...);
  }

  template <typename Iter>
  void UninitializedCopy(Iter src, Iter src_last, value_type* dst) {
    for (; src != src_last; ++dst, ++src) Construct(dst, *src);
  }

  template <typename... Args>
  void UninitializedFill(value_type* dst, value_type* dst_last,
                         const Args&... args) {
    for (; dst != dst_last; ++dst) Construct(dst, args...);
  }

  // Destroy [ptr, ptr_last) in place.
  void Destroy(value_type* ptr, value_type* ptr_last);

  template <typename Iter>
  void AppendRange(Iter first, Iter last, std::input_iterator_tag) {
    std::copy(first, last, std::back_inserter(*this));
  }

  // Faster path for forward iterators.
  template <typename Iter>
  void AppendRange(Iter first, Iter last, std::forward_iterator_tag);

  template <typename Iter>
  void AppendRange(Iter first, Iter last) {
    using IterTag = typename std::iterator_traits<Iter>::iterator_category;
    AppendRange(first, last, IterTag());
  }

  template <typename Iter>
  void AssignRange(Iter first, Iter last, std::input_iterator_tag);

  // Faster path for forward iterators.
  template <typename Iter>
  void AssignRange(Iter first, Iter last, std::forward_iterator_tag);

  template <typename Iter>
  void AssignRange(Iter first, Iter last) {
    using IterTag = typename std::iterator_traits<Iter>::iterator_category;
    AssignRange(first, last, IterTag());
  }

  iterator InsertWithCount(const_iterator position, size_type n,
                           const value_type& v);

  template <typename InputIter>
  iterator InsertWithRange(const_iterator position, InputIter first,
                           InputIter last, std::input_iterator_tag);
  template <typename ForwardIter>
  iterator InsertWithRange(const_iterator position, ForwardIter first,
                           ForwardIter last, std::forward_iterator_tag);

  AllocatorAndTag allocator_and_tag_;

  // Either the inlined or allocated representation
  union Rep {
    // Use struct to perform indirection that solves a bizarre compilation
    // error on Visual Studio (all known versions).
    struct {
      typename std::aligned_storage<sizeof(value_type),
                                    alignof(value_type)>::type inlined[N];
    } inlined_storage;
    struct {
      typename std::aligned_storage<sizeof(Allocation),
                                    alignof(Allocation)>::type allocation;
    } allocation_storage;
  } rep_;
};

// -----------------------------------------------------------------------------
// InlinedVector Non-Member Functions
// -----------------------------------------------------------------------------

// swap()
//
// Swaps the contents of two inlined vectors. This convenience function
// simply calls InlinedVector::swap(other_inlined_vector).
template <typename T, size_t N, typename A>
void swap(InlinedVector<T, N, A>& a,
          InlinedVector<T, N, A>& b) noexcept(noexcept(a.swap(b))) {
  a.swap(b);
}

// operator==()
//
// Tests the equivalency of the contents of two inlined vectors.
template <typename T, size_t N, typename A>
bool operator==(const InlinedVector<T, N, A>& a,
                const InlinedVector<T, N, A>& b) {
  return absl::equal(a.begin(), a.end(), b.begin(), b.end());
}

// operator!=()
//
// Tests the inequality of the contents of two inlined vectors.
template <typename T, size_t N, typename A>
bool operator!=(const InlinedVector<T, N, A>& a,
                const InlinedVector<T, N, A>& b) {
  return !(a == b);
}

// operator<()
//
// Tests whether the contents of one inlined vector are less than the contents
// of another through a lexicographical comparison operation.
template <typename T, size_t N, typename A>
bool operator<(const InlinedVector<T, N, A>& a,
               const InlinedVector<T, N, A>& b) {
  return std::lexicographical_compare(a.begin(), a.end(), b.begin(), b.end());
}

// operator>()
//
// Tests whether the contents of one inlined vector are greater than the
// contents of another through a lexicographical comparison operation.
template <typename T, size_t N, typename A>
bool operator>(const InlinedVector<T, N, A>& a,
               const InlinedVector<T, N, A>& b) {
  return b < a;
}

// operator<=()
//
// Tests whether the contents of one inlined vector are less than or equal to
// the contents of another through a lexicographical comparison operation.
template <typename T, size_t N, typename A>
bool operator<=(const InlinedVector<T, N, A>& a,
                const InlinedVector<T, N, A>& b) {
  return !(b < a);
}

// operator>=()
//
// Tests whether the contents of one inlined vector are greater than or equal to
// the contents of another through a lexicographical comparison operation.
template <typename T, size_t N, typename A>
bool operator>=(const InlinedVector<T, N, A>& a,
                const InlinedVector<T, N, A>& b) {
  return !(a < b);
}

// -----------------------------------------------------------------------------
// Implementation of InlinedVector
// -----------------------------------------------------------------------------
//
// Do not depend on any implementation details below this line.

template <typename T, size_t N, typename A>
InlinedVector<T, N, A>::InlinedVector(const InlinedVector& v)
    : allocator_and_tag_(v.allocator()) {
  reserve(v.size());
  if (allocated()) {
    UninitializedCopy(v.begin(), v.end(), allocated_space());
    tag().set_allocated_size(v.size());
  } else {
    UninitializedCopy(v.begin(), v.end(), inlined_space());
    tag().set_inline_size(v.size());
  }
}

template <typename T, size_t N, typename A>
InlinedVector<T, N, A>::InlinedVector(const InlinedVector& v,
                                      const allocator_type& alloc)
    : allocator_and_tag_(alloc) {
  reserve(v.size());
  if (allocated()) {
    UninitializedCopy(v.begin(), v.end(), allocated_space());
    tag().set_allocated_size(v.size());
  } else {
    UninitializedCopy(v.begin(), v.end(), inlined_space());
    tag().set_inline_size(v.size());
  }
}

template <typename T, size_t N, typename A>
InlinedVector<T, N, A>::InlinedVector(InlinedVector&& v) noexcept(
    absl::allocator_is_nothrow<allocator_type>::value ||
    std::is_nothrow_move_constructible<value_type>::value)
    : allocator_and_tag_(v.allocator_and_tag_) {
  if (v.allocated()) {
    // We can just steal the underlying buffer from the source.
    // That leaves the source empty, so we clear its size.
    init_allocation(v.allocation());
    v.tag() = Tag();
  } else {
    UninitializedCopy(std::make_move_iterator(v.inlined_space()),
                      std::make_move_iterator(v.inlined_space() + v.size()),
                      inlined_space());
  }
}

template <typename T, size_t N, typename A>
InlinedVector<T, N, A>::InlinedVector(
    InlinedVector&& v,
    const allocator_type&
        alloc) noexcept(absl::allocator_is_nothrow<allocator_type>::value)
    : allocator_and_tag_(alloc) {
  if (v.allocated()) {
    if (alloc == v.allocator()) {
      // We can just steal the allocation from the source.
      tag() = v.tag();
      init_allocation(v.allocation());
      v.tag() = Tag();
    } else {
      // We need to use our own allocator
      reserve(v.size());
      UninitializedCopy(std::make_move_iterator(v.begin()),
                        std::make_move_iterator(v.end()), allocated_space());
      tag().set_allocated_size(v.size());
    }
  } else {
    UninitializedCopy(std::make_move_iterator(v.inlined_space()),
                      std::make_move_iterator(v.inlined_space() + v.size()),
                      inlined_space());
    tag().set_inline_size(v.size());
  }
}

template <typename T, size_t N, typename A>
void InlinedVector<T, N, A>::InitAssign(size_type n, const value_type& t) {
  if (n > static_cast<size_type>(N)) {
    Allocation new_allocation(allocator(), n);
    init_allocation(new_allocation);
    UninitializedFill(allocated_space(), allocated_space() + n, t);
    tag().set_allocated_size(n);
  } else {
    UninitializedFill(inlined_space(), inlined_space() + n, t);
    tag().set_inline_size(n);
  }
}

template <typename T, size_t N, typename A>
void InlinedVector<T, N, A>::InitAssign(size_type n) {
  if (n > static_cast<size_type>(N)) {
    Allocation new_allocation(allocator(), n);
    init_allocation(new_allocation);
    UninitializedFill(allocated_space(), allocated_space() + n);
    tag().set_allocated_size(n);
  } else {
    UninitializedFill(inlined_space(), inlined_space() + n);
    tag().set_inline_size(n);
  }
}

template <typename T, size_t N, typename A>
void InlinedVector<T, N, A>::resize(size_type n) {
  size_type s = size();
  if (n < s) {
    erase(begin() + n, end());
    return;
  }
  reserve(n);
  assert(capacity() >= n);

  // Fill new space with elements constructed in-place.
  if (allocated()) {
    UninitializedFill(allocated_space() + s, allocated_space() + n);
    tag().set_allocated_size(n);
  } else {
    UninitializedFill(inlined_space() + s, inlined_space() + n);
    tag().set_inline_size(n);
  }
}

template <typename T, size_t N, typename A>
void InlinedVector<T, N, A>::resize(size_type n, const value_type& elem) {
  size_type s = size();
  if (n < s) {
    erase(begin() + n, end());
    return;
  }
  reserve(n);
  assert(capacity() >= n);

  // Fill new space with copies of 'elem'.
  if (allocated()) {
    UninitializedFill(allocated_space() + s, allocated_space() + n, elem);
    tag().set_allocated_size(n);
  } else {
    UninitializedFill(inlined_space() + s, inlined_space() + n, elem);
    tag().set_inline_size(n);
  }
}

template <typename T, size_t N, typename A>
template <typename... Args>
typename InlinedVector<T, N, A>::iterator InlinedVector<T, N, A>::emplace(
    const_iterator position, Args&&... args) {
  assert(position >= begin());
  assert(position <= end());
  if (position == end()) {
    emplace_back(std::forward<Args>(args)...);
    return end() - 1;
  }
  size_type s = size();
  size_type idx = std::distance(cbegin(), position);
  if (s == capacity()) {
    EnlargeBy(1);
  }
  assert(s < capacity());
  iterator pos = begin() + idx;  // Set 'pos' to a post-enlarge iterator.

  pointer space;
  if (allocated()) {
    tag().set_allocated_size(s + 1);
    space = allocated_space();
  } else {
    tag().set_inline_size(s + 1);
    space = inlined_space();
  }
  Construct(space + s, std::move(space[s - 1]));
  std::move_backward(pos, space + s - 1, space + s);
  Destroy(pos, pos + 1);
  Construct(pos, std::forward<Args>(args)...);

  return pos;
}

template <typename T, size_t N, typename A>
typename InlinedVector<T, N, A>::iterator InlinedVector<T, N, A>::erase(
    const_iterator first, const_iterator last) {
  assert(begin() <= first);
  assert(first <= last);
  assert(last <= end());

  iterator range_start = const_cast<iterator>(first);
  iterator range_end = const_cast<iterator>(last);

  size_type s = size();
  ptrdiff_t erase_gap = std::distance(range_start, range_end);
  if (erase_gap > 0) {
    pointer space;
    if (allocated()) {
      space = allocated_space();
      tag().set_allocated_size(s - erase_gap);
    } else {
      space = inlined_space();
      tag().set_inline_size(s - erase_gap);
    }
    std::move(range_end, space + s, range_start);
    Destroy(space + s - erase_gap, space + s);
  }
  return range_start;
}

template <typename T, size_t N, typename A>
void InlinedVector<T, N, A>::swap(InlinedVector& other) {
  using std::swap;  // Augment ADL with std::swap.
  if (&other == this) {
    return;
  }
  if (allocated() && other.allocated()) {
    // Both out of line, so just swap the tag, allocation, and allocator.
    swap(tag(), other.tag());
    swap(allocation(), other.allocation());
    swap(allocator(), other.allocator());
    return;
  }
  if (!allocated() && !other.allocated()) {
    // Both inlined: swap up to smaller size, then move remaining elements.
    InlinedVector* a = this;
    InlinedVector* b = &other;
    if (size() < other.size()) {
      swap(a, b);
    }

    const size_type a_size = a->size();
    const size_type b_size = b->size();
    assert(a_size >= b_size);
    // 'a' is larger. Swap the elements up to the smaller array size.
    std::swap_ranges(a->inlined_space(),
                     a->inlined_space() + b_size,
                     b->inlined_space());

    // Move the remaining elements: A[b_size,a_size) -> B[b_size,a_size)
    b->UninitializedCopy(a->inlined_space() + b_size,
                         a->inlined_space() + a_size,
                         b->inlined_space() + b_size);
    a->Destroy(a->inlined_space() + b_size, a->inlined_space() + a_size);

    swap(a->tag(), b->tag());
    swap(a->allocator(), b->allocator());
    assert(b->size() == a_size);
    assert(a->size() == b_size);
    return;
  }
  // One is out of line, one is inline.
  // We first move the elements from the inlined vector into the
  // inlined space in the other vector.  We then put the other vector's
  // pointer/capacity into the originally inlined vector and swap
  // the tags.
  InlinedVector* a = this;
  InlinedVector* b = &other;
  if (a->allocated()) {
    swap(a, b);
  }
  assert(!a->allocated());
  assert(b->allocated());
  const size_type a_size = a->size();
  const size_type b_size = b->size();
  // In an optimized build, b_size would be unused.
  (void)b_size;

  // Made Local copies of size(), don't need tag() accurate anymore
  swap(a->tag(), b->tag());

  // Copy b_allocation out before b's union gets clobbered by inline_space.
  Allocation b_allocation = b->allocation();

  b->UninitializedCopy(a->inlined_space(), a->inlined_space() + a_size,
                       b->inlined_space());
  a->Destroy(a->inlined_space(), a->inlined_space() + a_size);

  a->allocation() = b_allocation;

  if (a->allocator() != b->allocator()) {
    swap(a->allocator(), b->allocator());
  }

  assert(b->size() == a_size);
  assert(a->size() == b_size);
}

template <typename T, size_t N, typename A>
void InlinedVector<T, N, A>::EnlargeBy(size_type delta) {
  const size_type s = size();
  assert(s <= capacity());

  size_type target = std::max(static_cast<size_type>(N), s + delta);

  // Compute new capacity by repeatedly doubling current capacity
  // TODO(psrc): Check and avoid overflow?
  size_type new_capacity = capacity();
  while (new_capacity < target) {
    new_capacity <<= 1;
  }

  Allocation new_allocation(allocator(), new_capacity);

  UninitializedCopy(std::make_move_iterator(data()),
                    std::make_move_iterator(data() + s),
                    new_allocation.buffer());

  ResetAllocation(new_allocation, s);
}

template <typename T, size_t N, typename A>
auto InlinedVector<T, N, A>::ShiftRight(const_iterator position, size_type n)
    -> std::pair<iterator, iterator> {
  iterator start_used = const_cast<iterator>(position);
  iterator start_raw = const_cast<iterator>(position);
  size_type s = size();
  size_type required_size = s + n;

  if (required_size > capacity()) {
    // Compute new capacity by repeatedly doubling current capacity
    size_type new_capacity = capacity();
    while (new_capacity < required_size) {
      new_capacity <<= 1;
    }
    // Move everyone into the new allocation, leaving a gap of n for the
    // requested shift.
    Allocation new_allocation(allocator(), new_capacity);
    size_type index = position - begin();
    UninitializedCopy(std::make_move_iterator(data()),
                      std::make_move_iterator(data() + index),
                      new_allocation.buffer());
    UninitializedCopy(std::make_move_iterator(data() + index),
                      std::make_move_iterator(data() + s),
                      new_allocation.buffer() + index + n);
    ResetAllocation(new_allocation, s);

    // New allocation means our iterator is invalid, so we'll recalculate.
    // Since the entire gap is in new space, there's no used space to reuse.
    start_raw = begin() + index;
    start_used = start_raw;
  } else {
    // If we had enough space, it's a two-part move. Elements going into
    // previously-unoccupied space need an UninitializedCopy. Elements
    // going into a previously-occupied space are just a move.
    iterator pos = const_cast<iterator>(position);
    iterator raw_space = end();
    size_type slots_in_used_space = raw_space - pos;
    size_type new_elements_in_used_space = std::min(n, slots_in_used_space);
    size_type new_elements_in_raw_space = n - new_elements_in_used_space;
    size_type old_elements_in_used_space =
        slots_in_used_space - new_elements_in_used_space;

    UninitializedCopy(std::make_move_iterator(pos + old_elements_in_used_space),
                      std::make_move_iterator(raw_space),
                      raw_space + new_elements_in_raw_space);
    std::move_backward(pos, pos + old_elements_in_used_space, raw_space);

    // If the gap is entirely in raw space, the used space starts where the raw
    // space starts, leaving no elements in used space. If the gap is entirely
    // in used space, the raw space starts at the end of the gap, leaving all
    // elements accounted for within the used space.
    start_used = pos;
    start_raw = pos + new_elements_in_used_space;
  }
  return std::make_pair(start_used, start_raw);
}

template <typename T, size_t N, typename A>
void InlinedVector<T, N, A>::Destroy(value_type* ptr, value_type* ptr_last) {
  for (value_type* p = ptr; p != ptr_last; ++p) {
    AllocatorTraits::destroy(allocator(), p);
  }

  // Overwrite unused memory with 0xab so we can catch uninitialized usage.
  // Cast to void* to tell the compiler that we don't care that we might be
  // scribbling on a vtable pointer.
#ifndef NDEBUG
  if (ptr != ptr_last) {
    memset(reinterpret_cast<void*>(ptr), 0xab,
           sizeof(*ptr) * (ptr_last - ptr));
  }
#endif
}

template <typename T, size_t N, typename A>
template <typename Iter>
void InlinedVector<T, N, A>::AppendRange(Iter first, Iter last,
                                         std::forward_iterator_tag) {
  using Length = typename std::iterator_traits<Iter>::difference_type;
  Length length = std::distance(first, last);
  reserve(size() + length);
  if (allocated()) {
    UninitializedCopy(first, last, allocated_space() + size());
    tag().set_allocated_size(size() + length);
  } else {
    UninitializedCopy(first, last, inlined_space() + size());
    tag().set_inline_size(size() + length);
  }
}

template <typename T, size_t N, typename A>
template <typename Iter>
void InlinedVector<T, N, A>::AssignRange(Iter first, Iter last,
                                         std::input_iterator_tag) {
  // Optimized to avoid reallocation.
  // Prefer reassignment to copy construction for elements.
  iterator out = begin();
  for ( ; first != last && out != end(); ++first, ++out)
    *out = *first;
  erase(out, end());
  std::copy(first, last, std::back_inserter(*this));
}

template <typename T, size_t N, typename A>
template <typename Iter>
void InlinedVector<T, N, A>::AssignRange(Iter first, Iter last,
                                         std::forward_iterator_tag) {
  using Length = typename std::iterator_traits<Iter>::difference_type;
  Length length = std::distance(first, last);
  // Prefer reassignment to copy construction for elements.
  if (static_cast<size_type>(length) <= size()) {
    erase(std::copy(first, last, begin()), end());
    return;
  }
  reserve(length);
  iterator out = begin();
  for (; out != end(); ++first, ++out) *out = *first;
  if (allocated()) {
    UninitializedCopy(first, last, out);
    tag().set_allocated_size(length);
  } else {
    UninitializedCopy(first, last, out);
    tag().set_inline_size(length);
  }
}

template <typename T, size_t N, typename A>
auto InlinedVector<T, N, A>::InsertWithCount(const_iterator position,
                                             size_type n, const value_type& v)
    -> iterator {
  assert(position >= begin() && position <= end());
  if (n == 0) return const_cast<iterator>(position);
  std::pair<iterator, iterator> it_pair = ShiftRight(position, n);
  std::fill(it_pair.first, it_pair.second, v);
  UninitializedFill(it_pair.second, it_pair.first + n, v);
  tag().add_size(n);
  return it_pair.first;
}

template <typename T, size_t N, typename A>
template <typename InputIter>
auto InlinedVector<T, N, A>::InsertWithRange(const_iterator position,
                                             InputIter first, InputIter last,
                                             std::input_iterator_tag)
    -> iterator {
  assert(position >= begin() && position <= end());
  size_type index = position - cbegin();
  size_type i = index;
  while (first != last) insert(begin() + i++, *first++);
  return begin() + index;
}

// Overload of InlinedVector::InsertWithRange()
template <typename T, size_t N, typename A>
template <typename ForwardIter>
auto InlinedVector<T, N, A>::InsertWithRange(const_iterator position,
                                             ForwardIter first,
                                             ForwardIter last,
                                             std::forward_iterator_tag)
    -> iterator {
  assert(position >= begin() && position <= end());
  if (first == last) {
    return const_cast<iterator>(position);
  }
  using Length = typename std::iterator_traits<ForwardIter>::difference_type;
  Length n = std::distance(first, last);
  std::pair<iterator, iterator> it_pair = ShiftRight(position, n);
  size_type used_spots = it_pair.second - it_pair.first;
  ForwardIter open_spot = std::next(first, used_spots);
  std::copy(first, open_spot, it_pair.first);
  UninitializedCopy(open_spot, last, it_pair.second);
  tag().add_size(n);
  return it_pair.first;
}

}  // namespace absl

#endif  // ABSL_CONTAINER_INLINED_VECTOR_H_