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> 15 // OutputIterator exclusive_scan(InputIterator first, InputIterator last, 16 // OutputIterator result, T init); 17 // 18 19 #include <algorithm> 20 #include <array> 21 #include <cassert> 22 #include <cstddef> 23 #include <numeric> 24 25 #include "test_macros.h" 26 #include "test_iterators.h" 27 28 template <class Iter1, class T> 29 TEST_CONSTEXPR_CXX20 void 30 test(Iter1 first, Iter1 last, T init, const T *rFirst, const T *rLast) 31 { 32 assert((rLast - rFirst) <= 5); // or else increase the size of "out" 33 T out[5]; 34 35 // Not in place 36 T *end = std::exclusive_scan(first, last, out, init); 37 assert(std::equal(out, end, rFirst, rLast)); 38 39 // In place 40 std::copy(first, last, out); 41 end = std::exclusive_scan(out, end, out, init); 42 assert(std::equal(out, end, rFirst, rLast)); 43 } 44 45 template <class Iter> 46 TEST_CONSTEXPR_CXX20 void 47 test() 48 { 49 int ia[] = {1, 3, 5, 7, 9}; 50 const int pRes[] = {0, 1, 4, 9, 16}; 51 const unsigned sa = sizeof(ia) / sizeof(ia[0]); 52 static_assert(sa == sizeof(pRes) / sizeof(pRes[0])); // just to be sure 53 54 for (unsigned int i = 0; i < sa; ++i) { 55 test(Iter(ia), Iter(ia + i), 0, pRes, pRes + i); 56 } 57 } 58 59 constexpr std::size_t triangle(size_t n) { return n*(n+1)/2; } 60 61 // Basic sanity 62 TEST_CONSTEXPR_CXX20 void 63 basic_tests() 64 { 65 { 66 std::array<std::size_t, 10> v; 67 std::fill(v.begin(), v.end(), 3); 68 std::exclusive_scan(v.begin(), v.end(), v.begin(), std::size_t{50}); 69 for (std::size_t i = 0; i < v.size(); ++i) 70 assert(v[i] == 50 + i * 3); 71 } 72 73 { 74 std::array<std::size_t, 10> v; 75 std::iota(v.begin(), v.end(), 0); 76 std::exclusive_scan(v.begin(), v.end(), v.begin(), std::size_t{30}); 77 for (std::size_t i = 0; i < v.size(); ++i) 78 assert(v[i] == 30 + triangle(i-1)); 79 } 80 81 { 82 std::array<std::size_t, 10> v; 83 std::iota(v.begin(), v.end(), 1); 84 std::exclusive_scan(v.begin(), v.end(), v.begin(), std::size_t{40}); 85 for (std::size_t i = 0; i < v.size(); ++i) 86 assert(v[i] == 40 + triangle(i)); 87 } 88 89 } 90 91 TEST_CONSTEXPR_CXX20 bool 92 test() 93 { 94 basic_tests(); 95 96 // All the iterator categories 97 test<cpp17_input_iterator <const int*> >(); 98 test<forward_iterator <const int*> >(); 99 test<bidirectional_iterator<const int*> >(); 100 test<random_access_iterator<const int*> >(); 101 test<const int*>(); 102 test< int*>(); 103 104 return true; 105 } 106 107 int main(int, char**) 108 { 109 test(); 110 #if TEST_STD_VER > 17 111 static_assert(test()); 112 #endif 113 return 0; 114 } 115