rend.pass.cpp
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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
// <span>
// constexpr reverse_iterator rend() const noexcept;
// constexpr const_reverse_iterator crend() const noexcept;
#include <span>
#include <cassert>
#include <string>
#include "test_macros.h"
template <class Span>
constexpr bool testConstexprSpan(Span s)
{
bool ret = true;
typename Span::reverse_iterator e = s.rend();
if (s.empty())
{
ret = ret && (e == s.rbegin());
}
else
{
ret = ret && (e != s.rbegin());
}
ret = ret && (static_cast<size_t>(e - s.rbegin()) == s.size());
return ret;
}
template <class Span>
void testRuntimeSpan(Span s)
{
typename Span::reverse_iterator e = s.rend();
if (s.empty())
{
assert(e == s.rbegin());
}
else
{
assert(e != s.rbegin());
}
assert(static_cast<size_t>(e - s.rbegin()) == s.size());
}
struct A{};
bool operator==(A, A) {return true;}
constexpr int iArr1[] = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9};
int iArr2[] = {10, 11, 12, 13, 14, 15, 16, 17, 18, 19};
int main(int, char**)
{
static_assert(testConstexprSpan(std::span<int>()), "");
static_assert(testConstexprSpan(std::span<long>()), "");
static_assert(testConstexprSpan(std::span<double>()), "");
static_assert(testConstexprSpan(std::span<A>()), "");
static_assert(testConstexprSpan(std::span<std::string>()), "");
static_assert(testConstexprSpan(std::span<int, 0>()), "");
static_assert(testConstexprSpan(std::span<long, 0>()), "");
static_assert(testConstexprSpan(std::span<double, 0>()), "");
static_assert(testConstexprSpan(std::span<A, 0>()), "");
static_assert(testConstexprSpan(std::span<std::string, 0>()), "");
static_assert(testConstexprSpan(std::span<const int>(iArr1, 1)), "");
static_assert(testConstexprSpan(std::span<const int>(iArr1, 2)), "");
static_assert(testConstexprSpan(std::span<const int>(iArr1, 3)), "");
static_assert(testConstexprSpan(std::span<const int>(iArr1, 4)), "");
static_assert(testConstexprSpan(std::span<const int>(iArr1, 5)), "");
testRuntimeSpan(std::span<int> ());
testRuntimeSpan(std::span<long> ());
testRuntimeSpan(std::span<double> ());
testRuntimeSpan(std::span<A> ());
testRuntimeSpan(std::span<std::string>());
testRuntimeSpan(std::span<int, 0> ());
testRuntimeSpan(std::span<long, 0> ());
testRuntimeSpan(std::span<double, 0> ());
testRuntimeSpan(std::span<A, 0> ());
testRuntimeSpan(std::span<std::string, 0>());
testRuntimeSpan(std::span<int>(iArr2, 1));
testRuntimeSpan(std::span<int>(iArr2, 2));
testRuntimeSpan(std::span<int>(iArr2, 3));
testRuntimeSpan(std::span<int>(iArr2, 4));
testRuntimeSpan(std::span<int>(iArr2, 5));
std::string s;
testRuntimeSpan(std::span<std::string>(&s, (std::size_t) 0));
testRuntimeSpan(std::span<std::string>(&s, 1));
return 0;
}