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//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
// UNSUPPORTED: c++03, c++11, c++14, c++17
// friend constexpr iterator operator-(iterator i, difference_type n)
// requires advanceable<W>;
// friend constexpr difference_type operator-(const iterator& x, const iterator& y)
// requires advanceable<W>;
#include <cassert>
#include <cstdint>
#include <ranges>
#include <type_traits>
#include "test_macros.h"
#include "../types.h"
// If we're compiling for 32 bit or windows, int and long are the same size, so long long is the correct difference type.
#if INTPTR_MAX == INT32_MAX || defined(_WIN32)
using IntDiffT = long long;
#else
using IntDiffT = long;
#endif
constexpr bool test() {
// <iterator> - difference_type
{
// When "_Start" is signed integer like.
{
std::ranges::iota_view<int> io(0);
auto iter1 = std::next(io.begin(), 10);
auto iter2 = std::next(io.begin(), 10);
assert(iter1 == iter2);
assert(iter1 - 5 != iter2);
assert(iter1 - 5 == std::ranges::prev(iter2, 5));
static_assert(!std::is_reference_v<decltype(iter2 - 5)>);
}
// When "_Start" is not integer like.
{
std::ranges::iota_view io(SomeInt(0));
auto iter1 = std::next(io.begin(), 10);
auto iter2 = std::next(io.begin(), 10);
assert(iter1 == iter2);
assert(iter1 - 5 != iter2);
assert(iter1 - 5 == std::ranges::prev(iter2, 5));
static_assert(!std::is_reference_v<decltype(iter2 - 5)>);
}
// When "_Start" is unsigned integer like and n is greater than or equal to zero.
{
std::ranges::iota_view<unsigned> io(0);
auto iter1 = std::next(io.begin(), 10);
auto iter2 = std::next(io.begin(), 10);
assert(iter1 == iter2);
assert(iter1 - 5 != iter2);
assert(iter1 - 5 == std::ranges::prev(iter2, 5));
static_assert(!std::is_reference_v<decltype(iter2 - 5)>);
}
{
std::ranges::iota_view<unsigned> io(0);
auto iter1 = std::next(io.begin(), 10);
auto iter2 = std::next(io.begin(), 10);
assert(iter1 - 0 == iter2);
}
// When "_Start" is unsigned integer like and n is less than zero.
{
std::ranges::iota_view<unsigned> io(0);
auto iter1 = std::next(io.begin(), 10);
auto iter2 = std::next(io.begin(), 10);
assert(iter1 - 5 != iter2);
assert(iter1 - 5 == std::ranges::prev(iter2, 5));
static_assert(!std::is_reference_v<decltype(iter2 - 5)>);
}
}
// <iterator> - <iterator>
{
// When "_Start" is signed integer like.
{
std::ranges::iota_view<int> io(0);
auto iter1 = std::next(io.begin(), 10);
auto iter2 = std::next(io.begin(), 5);
assert(iter1 - iter2 == 5);
LIBCPP_STATIC_ASSERT(std::same_as<decltype(iter1 - iter2), IntDiffT>);
}
{
std::ranges::iota_view<int> io(0);
auto iter1 = std::next(io.begin(), 10);
auto iter2 = std::next(io.begin(), 10);
assert(iter1 - iter2 == 0);
LIBCPP_STATIC_ASSERT(std::same_as<decltype(iter1 - iter2), IntDiffT>);
}
{
std::ranges::iota_view<int> io(0);
auto iter1 = std::next(io.begin(), 5);
auto iter2 = std::next(io.begin(), 10);
assert(iter1 - iter2 == -5);
LIBCPP_STATIC_ASSERT(std::same_as<decltype(iter1 - iter2), IntDiffT>);
}
// When "_Start" is unsigned integer like and y > x.
{
std::ranges::iota_view<unsigned> io(0);
auto iter1 = std::next(io.begin(), 5);
auto iter2 = std::next(io.begin(), 10);
assert(iter1 - iter2 == -5);
LIBCPP_STATIC_ASSERT(std::same_as<decltype(iter1 - iter2), IntDiffT>);
}
// When "_Start" is unsigned integer like and x >= y.
{
std::ranges::iota_view<unsigned> io(0);
auto iter1 = std::next(io.begin(), 10);
auto iter2 = std::next(io.begin(), 5);
assert(iter1 - iter2 == 5);
LIBCPP_STATIC_ASSERT(std::same_as<decltype(iter1 - iter2), IntDiffT>);
}
{
std::ranges::iota_view<unsigned> io(0);
auto iter1 = std::next(io.begin(), 10);
auto iter2 = std::next(io.begin(), 10);
assert(iter1 - iter2 == 0);
LIBCPP_STATIC_ASSERT(std::same_as<decltype(iter1 - iter2), IntDiffT>);
}
// When "_Start" is not integer like.
{
std::ranges::iota_view io(SomeInt(0));
auto iter1 = std::next(io.begin(), 10);
auto iter2 = std::next(io.begin(), 5);
assert(iter1 - iter2 == 5);
static_assert(std::same_as<decltype(iter1 - iter2), int>);
}
{
std::ranges::iota_view io(SomeInt(0));
auto iter1 = std::next(io.begin(), 10);
auto iter2 = std::next(io.begin(), 10);
assert(iter1 - iter2 == 0);
static_assert(std::same_as<decltype(iter1 - iter2), int>);
}
{
std::ranges::iota_view io(SomeInt(0));
auto iter1 = std::next(io.begin(), 5);
auto iter2 = std::next(io.begin(), 10);
assert(iter1 - iter2 == -5);
static_assert(std::same_as<decltype(iter1 - iter2), int>);
}
}
return true;
}
int main(int, char**) {
test();
static_assert(test());
return 0;
}
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