115 lines · 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-exception6//7//===----------------------------------------------------------------------===//8 9// UNSUPPORTED: c++03, c++11, c++1410 11// <numeric>12 13// Became constexpr in C++2014// 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 28template <class Iter1, class T>29TEST_CONSTEXPR_CXX20 void30test(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 place36 T *end = std::exclusive_scan(first, last, out, init);37 assert(std::equal(out, end, rFirst, rLast));38 39 // In place40 std::copy(first, last, out);41 end = std::exclusive_scan(out, end, out, init);42 assert(std::equal(out, end, rFirst, rLast));43}44 45template <class Iter>46TEST_CONSTEXPR_CXX20 void47test()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 sure53 54 for (unsigned int i = 0; i < sa; ++i) {55 test(Iter(ia), Iter(ia + i), 0, pRes, pRes + i);56 }57}58 59constexpr std::size_t triangle(size_t n) { return n*(n+1)/2; }60 61// Basic sanity62TEST_CONSTEXPR_CXX20 void63basic_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 91TEST_CONSTEXPR_CXX20 bool92test()93{94 basic_tests();95 96// All the iterator categories97 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 107int main(int, char**)108{109 test();110#if TEST_STD_VER > 17111 static_assert(test());112#endif113 return 0;114}115