libcxx/test/std/algorithms/alg.modifying.operations/alg.move/move_backward.pass.cpp

   1 //===----------------------------------------------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 // UNSUPPORTED: c++03 && !stdlib=libc++
  10
  11 // <algorithm>
  12
  13 // template<BidirectionalIterator InIter, BidirectionalIterator OutIter>
  14 //   requires OutputIterator<OutIter, RvalueOf<InIter::reference>::type>
  15 //   OutIter
  16 //   move_backward(InIter first, InIter last, OutIter result);
  17
  18 #include <algorithm>
  19 #include <cassert>
  20 #include <iterator>
  21 #include <memory>
  22
  23 #include "MoveOnly.h"
  24 #include "test_iterators.h"
  25 #include "test_macros.h"
  26
  27 class PaddedBase {
  28 public:
  29   TEST_CONSTEXPR PaddedBase(std::int16_t a, std::int8_t b) : a_(a), b_(b) {}
  30
  31   std::int16_t a_;
  32   std::int8_t b_;
  33 };
  34
  35 class Derived : public PaddedBase {
  36 public:
  37   TEST_CONSTEXPR Derived(std::int16_t a, std::int8_t b, std::int8_t c) : PaddedBase(a, b), c_(c) {}
  38
  39   std::int8_t c_;
  40 };
  41
  42 template <class InIter>
  43 struct Test {
  44   template <class OutIter>
  45   TEST_CONSTEXPR_CXX20 void operator()() {
  46     const unsigned N = 1000;
  47     int ia[N] = {};
  48     for (unsigned i = 0; i < N; ++i)
  49         ia[i] = i;
  50     int ib[N] = {0};
  51
  52     OutIter r = std::move_backward(InIter(ia), InIter(ia+N), OutIter(ib+N));
  53     assert(base(r) == ib);
  54     for (unsigned i = 0; i < N; ++i)
  55         assert(ia[i] == ib[i]);
  56   }
  57 };
  58
  59 struct TestOutIters {
  60   template <class InIter>
  61   TEST_CONSTEXPR_CXX20 void operator()() {
  62     types::for_each(
  63         types::concatenate_t<types::bidirectional_iterator_list<int*> >(),
  64         Test<InIter>());
  65   }
  66 };
  67
  68 template <class InIter>
  69 struct Test1 {
  70   template <class OutIter>
  71   TEST_CONSTEXPR_CXX23 void operator()() {
  72     const unsigned N = 100;
  73     std::unique_ptr<int> ia[N];
  74     for (unsigned i = 0; i < N; ++i)
  75         ia[i].reset(new int(i));
  76     std::unique_ptr<int> ib[N];
  77
  78     OutIter r = std::move_backward(InIter(ia), InIter(ia+N), OutIter(ib+N));
  79     assert(base(r) == ib);
  80     for (unsigned i = 0; i < N; ++i)
  81         assert(*ib[i] == static_cast<int>(i));
  82   }
  83 };
  84
  85 struct Test1OutIters {
  86   template <class InIter>
  87   TEST_CONSTEXPR_CXX23 void operator()() {
  88     types::for_each(types::concatenate_t<types::bidirectional_iterator_list<std::unique_ptr<int>*> >(),
  89                     Test1<InIter>());
  90   }
  91 };
  92
  93 TEST_CONSTEXPR_CXX20 bool test() {
  94   types::for_each(types::bidirectional_iterator_list<int*>(), TestOutIters());
  95   if (TEST_STD_AT_LEAST_23_OR_RUNTIME_EVALUATED)
  96     types::for_each(types::bidirectional_iterator_list<std::unique_ptr<int>*>(), Test1OutIters());
  97
  98   { // Make sure that padding bits aren't copied
  99     Derived src(1, 2, 3);
 100     Derived dst(4, 5, 6);
 101     std::move_backward(
 102         static_cast<PaddedBase*>(&src), static_cast<PaddedBase*>(&src) + 1, static_cast<PaddedBase*>(&dst) + 1);
 103     assert(dst.a_ == 1);
 104     assert(dst.b_ == 2);
 105     assert(dst.c_ == 6);
 106   }
 107
 108   { // Make sure that overlapping ranges can be copied
 109     int a[] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
 110     std::move_backward(a, a + 7, a + 10);
 111     int expected[] = {1, 2, 3, 1, 2, 3, 4, 5, 6, 7};
 112     assert(std::equal(a, a + 10, expected));
 113   }
 114
 115   // Make sure that the algorithm works with move-only types
 116   {
 117     // When non-trivial
 118     {
 119       MoveOnly from[3] = {1, 2, 3};
 120       MoveOnly to[3] = {};
 121       std::move_backward(std::begin(from), std::end(from), std::end(to));
 122       assert(to[0] == MoveOnly(1));
 123       assert(to[1] == MoveOnly(2));
 124       assert(to[2] == MoveOnly(3));
 125     }
 126     // When trivial
 127     {
 128       TrivialMoveOnly from[3] = {1, 2, 3};
 129       TrivialMoveOnly to[3] = {};
 130       std::move_backward(std::begin(from), std::end(from), std::end(to));
 131       assert(to[0] == TrivialMoveOnly(1));
 132       assert(to[1] == TrivialMoveOnly(2));
 133       assert(to[2] == TrivialMoveOnly(3));
 134     }
 135   }
 136
 137   return true;
 138 }
 139
 140 int main(int, char**)
 141 {
 142   test();
 143 #if TEST_STD_VER >= 20
 144   static_assert(test());
 145 #endif
 146
 147   return 0;
 148 }