libcxx/test/std/numerics/numeric.ops/exclusive.scan/exclusive_scan_init_op.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, c++11, c++14
  10
  11 // <numeric>
  12
  13 // Became constexpr in C++20
  14 // template<class InputIterator, class OutputIterator, class T, class BinaryOperation>
  15 //     OutputIterator
  16 //     exclusive_scan(InputIterator first, InputIterator last,
  17 //                    OutputIterator result,
  18 //                    T init, BinaryOperation binary_op); // C++17
  19
  20 #include <numeric>
  21 #include <algorithm>
  22 #include <array>
  23 #include <cassert>
  24 #include <functional>
  25 #include <iterator>
  26
  27 #include "test_macros.h"
  28 #include "test_iterators.h"
  29
  30 template <class Iter1, class T, class Op>
  31 TEST_CONSTEXPR_CXX20 void
  32 test(Iter1 first, Iter1 last, T init, Op op, const T *rFirst, const T *rLast)
  33 {
  34     assert((rLast - rFirst) <= 5);  // or else increase the size of "out"
  35     T out[5];
  36
  37     // Not in place
  38     T *end = std::exclusive_scan(first, last, out, init, op);
  39     assert(std::equal(out, end, rFirst, rLast));
  40
  41     // In place
  42     std::copy(first, last, out);
  43     end = std::exclusive_scan(out, end, out, init, op);
  44     assert(std::equal(out, end, rFirst, rLast));
  45 }
  46
  47
  48 template <class Iter>
  49 TEST_CONSTEXPR_CXX20 void
  50 test()
  51 {
  52     int ia[]         = {1, 3, 5,  7,   9};
  53     const int pRes[] = {0, 1, 4,  9,  16};
  54     const int mRes[] = {1, 1, 3, 15, 105};
  55     const unsigned sa = sizeof(ia) / sizeof(ia[0]);
  56     static_assert(sa == sizeof(pRes) / sizeof(pRes[0]));       // just to be sure
  57     static_assert(sa == sizeof(mRes) / sizeof(mRes[0]));       // just to be sure
  58
  59     for (unsigned int i = 0; i < sa; ++i ) {
  60         test(Iter(ia), Iter(ia + i), 0, std::plus<>(),       pRes, pRes + i);
  61         test(Iter(ia), Iter(ia + i), 1, std::multiplies<>(), mRes, mRes + i);
  62     }
  63 }
  64
  65 TEST_CONSTEXPR_CXX20 bool
  66 test()
  67 {
  68 //  All the iterator categories
  69     test<cpp17_input_iterator        <const int*> >();
  70     test<forward_iterator      <const int*> >();
  71     test<bidirectional_iterator<const int*> >();
  72     test<random_access_iterator<const int*> >();
  73     test<const int*>();
  74     test<      int*>();
  75
  76 //  Make sure that the calculations are done using the init typedef
  77     {
  78     std::array<unsigned char, 10> v;
  79     std::iota(v.begin(), v.end(), static_cast<unsigned char>(1));
  80     std::array<std::size_t, 10> res;
  81     std::exclusive_scan(v.begin(), v.end(), res.begin(), 1, std::multiplies<>());
  82
  83     assert(res.size() == 10);
  84     std::size_t j = 1;
  85     assert(res[0] == 1);
  86     for (std::size_t i = 1; i < v.size(); ++i)
  87     {
  88         j *= i;
  89         assert(res[i] == j);
  90     }
  91     }
  92
  93     return true;
  94 }
  95
  96 int main(int, char**)
  97 {
  98     test();
  99 #if TEST_STD_VER > 17
 100     static_assert(test());
 101 #endif
 102     return 0;
 103 }