fd66b44ec1
Those constructors are very easy to misuse -- one could easily think that the size passed to the constructor is the size of the range to exhibit from the subrange. Instead, it's a size hint and it's UB to get it wrong. Hence, when it's cheap to compute the real size of the range, it's cheap to make sure that the user didn't get it wrong. Differential Revision: https://reviews.llvm.org/D108827
68 lines
1.6 KiB
C++
68 lines
1.6 KiB
C++
//===----------------------------------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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// UNSUPPORTED: c++03, c++11, c++14, c++17
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// UNSUPPORTED: libcpp-no-concepts
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// UNSUPPORTED: libcpp-has-no-incomplete-ranges
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// class std::ranges::subrange;
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#include <ranges>
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#include <cassert>
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#include "test_iterators.h"
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#include "types.h"
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constexpr bool test() {
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int buff[] = {1, 2, 3, 4, 5};
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{
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std::ranges::subrange<MoveOnlyForwardIter, int*> a(MoveOnlyForwardIter(buff), buff + 5, 5);
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assert(a.begin().base == buff);
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assert(!a.empty());
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assert(a.size() == 5);
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}
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{
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std::ranges::subrange<ForwardIter> b(ForwardIter(nullptr), ForwardIter(nullptr));
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assert(b.empty());
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}
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{
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std::ranges::subrange<ForwardIter> c{ForwardIter(buff), ForwardIter(buff)};
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assert(c.empty());
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}
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{
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std::ranges::subrange<ForwardIter> d(ForwardIter(buff), ForwardIter(buff + 1));
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assert(!d.empty());
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}
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{
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bool minusWasCalled = false;
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SizedSentinelForwardIter beg(buff, &minusWasCalled), end(buff + 5, &minusWasCalled);
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std::ranges::subrange<SizedSentinelForwardIter> e(beg, end, 5);
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assert(!e.empty());
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// Make sure that operator- is used to calculate size when possible.
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minusWasCalled = false;
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assert(e.size() == 5);
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assert(minusWasCalled);
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}
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return true;
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}
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int main(int, char**) {
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test();
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static_assert(test());
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return 0;
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}
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