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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
//
//===----------------------------------------------------------------------===//
// <algorithm>
// UNSUPPORTED: c++03, c++11, c++14, c++17, c++20
// template<input_iterator I1, sentinel_for<I1> S1, input_iterator I2, sentinel_for<I2> S2,
// class Pred = ranges::equal_to, class Proj1 = identity, class Proj2 = identity>
// requires indirectly_comparable<I1, I2, Pred, Proj1, Proj2>
// constexpr bool ranges::starts_with(I1 first1, S1 last1, I2 first2, S2 last2, Pred pred = {},
// Proj1 proj1 = {}, Proj2 proj2 = {});
// template<input_range R1, input_range R2, class Pred = ranges::equal_to, class Proj1 = identity,
// class Proj2 = identity>
// requires indirectly_comparable<iterator_t<R1>, iterator_t<R2>, Pred, Proj1, Proj2>
// constexpr bool ranges::starts_with(R1&& r1, R2&& r2, Pred pred = {},
// Proj1 proj1 = {}, Proj2 proj2 = {});
#include <algorithm>
#include <array>
#include <ranges>
#include "almost_satisfies_types.h"
#include "test_iterators.h"
template <class Iter1, class Sent1 = Iter1, class Iter2 = int*, class Sent2 = Iter2>
concept HasStartsWithIt = requires(Iter1 first1, Sent1 last1, Iter2 first2, Sent2 last2) {
std::ranges::starts_with(first1, last1, first2, last2);
};
static_assert(HasStartsWithIt<int*>);
static_assert(HasStartsWithIt<ForwardIteratorNotDerivedFrom>);
static_assert(HasStartsWithIt<ForwardIteratorNotIncrementable>);
static_assert(!HasStartsWithIt<int*, SentinelForNotSemiregular>);
static_assert(!HasStartsWithIt<int*, int*, int**>); // not indirectly comparable
static_assert(!HasStartsWithIt<int*, SentinelForNotWeaklyEqualityComparableWith>);
static_assert(HasStartsWithIt<int*, int*, ForwardIteratorNotDerivedFrom>);
static_assert(HasStartsWithIt<int*, int*, ForwardIteratorNotIncrementable>);
static_assert(!HasStartsWithIt<int*, int*, int*, SentinelForNotSemiregular>);
static_assert(!HasStartsWithIt<int*, int*, int*, SentinelForNotWeaklyEqualityComparableWith>);
template <class Range1, class Range2 = UncheckedRange<int*>>
concept HasStartsWithR = requires(Range1 range1, Range2 range2) { std::ranges::starts_with(range1, range2); };
static_assert(HasStartsWithR<UncheckedRange<int*>>);
static_assert(HasStartsWithR<ForwardRangeNotDerivedFrom>);
static_assert(!HasStartsWithR<ForwardIteratorNotIncrementable>);
static_assert(!HasStartsWithR<ForwardRangeNotSentinelSemiregular>);
static_assert(!HasStartsWithR<ForwardRangeNotSentinelEqualityComparableWith>);
static_assert(!HasStartsWithR<UncheckedRange<int*>, UncheckedRange<int**>>); // not indirectly comparable
static_assert(HasStartsWithR<UncheckedRange<int*>, ForwardRangeNotDerivedFrom>);
static_assert(HasStartsWithR<UncheckedRange<int*>, ForwardRangeNotIncrementable>);
static_assert(!HasStartsWithR<UncheckedRange<int*>, ForwardRangeNotSentinelSemiregular>);
static_assert(!HasStartsWithR<UncheckedRange<int*>, ForwardRangeNotSentinelEqualityComparableWith>);
template <class Iter1, class Sent1 = Iter1, class Iter2, class Sent2 = Iter2>
constexpr void test_iterators() {
// simple tests
{
{
int a[] = {1, 2, 3, 4, 5, 6};
int p[] = {1, 2};
std::same_as<bool> decltype(auto) ret =
std::ranges::starts_with(Iter1(a), Sent1(Iter1(a + 6)), Iter2(p), Sent2(Iter2(p + 2)));
assert(ret);
}
{
int a[] = {1, 2, 3, 4, 5, 6};
int p[] = {1, 2};
auto whole = std::ranges::subrange(Iter1(a), Sent1(Iter1(a + 6)));
auto prefix = std::ranges::subrange(Iter2(p), Sent2(Iter2(p + 2)));
std::same_as<bool> decltype(auto) ret = std::ranges::starts_with(whole, prefix);
assert(ret);
}
}
// prefix doesn't match
{
{
int a[] = {1, 2, 3, 4, 5, 6};
int p[] = {4, 5, 6};
std::same_as<bool> decltype(auto) ret =
std::ranges::starts_with(Iter1(a), Sent1(Iter1(a + 6)), Iter2(p), Sent2(Iter2(p + 3)));
assert(!ret);
}
{
int a[] = {1, 2, 3, 4, 5, 6};
int p[] = {4, 5, 6};
auto whole = std::ranges::subrange(Iter1(a), Sent1(Iter1(a + 6)));
auto prefix = std::ranges::subrange(Iter2(p), Sent2(Iter2(p + 3)));
std::same_as<bool> decltype(auto) ret = std::ranges::starts_with(whole, prefix);
assert(!ret);
}
}
// range and prefix are identical
{
{
int a[] = {1, 2, 3, 4, 5, 6};
int p[] = {1, 2, 3, 4, 5, 6};
std::same_as<bool> decltype(auto) ret =
std::ranges::starts_with(Iter1(a), Sent1(Iter1(a + 6)), Iter2(p), Sent2(Iter2(p + 6)));
assert(ret);
}
{
int a[] = {1, 2, 3, 4, 5, 6};
int p[] = {1, 2, 3, 4, 5, 6};
auto whole = std::ranges::subrange(Iter1(a), Sent1(Iter1(a + 6)));
auto prefix = std::ranges::subrange(Iter2(p), Sent2(Iter2(p + 6)));
std::same_as<bool> decltype(auto) ret = std::ranges::starts_with(whole, prefix);
assert(ret);
}
}
// prefix is longer than range
{
{
int a[] = {1, 2, 3, 4, 5, 6};
int p[] = {1, 2, 3, 4, 5, 6, 7, 8};
std::same_as<bool> decltype(auto) ret =
std::ranges::starts_with(Iter1(a), Sent1(Iter1(a + 6)), Iter2(p), Sent2(Iter2(p + 8)));
assert(!ret);
}
{
int a[] = {1, 2, 3, 4, 5, 6};
int p[] = {1, 2, 3, 4, 5, 6, 7, 8};
auto whole = std::ranges::subrange(Iter1(a), Sent1(Iter1(a + 6)));
auto prefix = std::ranges::subrange(Iter2(p), Sent2(Iter2(p + 8)));
std::same_as<bool> decltype(auto) ret = std::ranges::starts_with(whole, prefix);
assert(!ret);
}
}
// prefix has zero length
{
{
int a[] = {1, 2, 3, 4, 5, 6};
int p[] = {};
std::same_as<bool> decltype(auto) ret =
std::ranges::starts_with(Iter1(a), Sent1(Iter1(a + 6)), Iter2(p), Sent2(Iter2(p)));
assert(ret);
}
{
int a[] = {1, 2, 3, 4, 5, 6};
int p[] = {};
auto whole = std::ranges::subrange(Iter1(a), Sent1(Iter1(a + 6)));
auto prefix = std::ranges::subrange(Iter2(p), Sent2(Iter2(p)));
std::same_as<bool> decltype(auto) ret = std::ranges::starts_with(whole, prefix);
assert(ret);
}
}
// range has zero length
{
{
int a[] = {};
int p[] = {1, 2, 3, 4, 5, 6, 7, 8};
std::same_as<bool> decltype(auto) ret =
std::ranges::starts_with(Iter1(a), Sent1(Iter1(a)), Iter2(p), Sent2(Iter2(p + 8)));
assert(!ret);
}
{
int a[] = {};
int p[] = {1, 2, 3, 4, 5, 6, 7, 8};
auto whole = std::ranges::subrange(Iter1(a), Sent1(Iter1(a)));
auto prefix = std::ranges::subrange(Iter2(p), Sent2(Iter2(p + 8)));
std::same_as<bool> decltype(auto) ret = std::ranges::starts_with(whole, prefix);
assert(!ret);
}
}
// check that the predicate is used
{
{
int a[] = {11, 8, 3, 4, 0, 6};
int p[] = {1, 12};
std::same_as<bool> decltype(auto) ret = std::ranges::starts_with(
Iter1(a), Sent1(Iter1(a + 6)), Iter2(p), Sent2(Iter2(p + 2)), [](int l, int r) { return l > r; });
assert(!ret);
}
{
int a[] = {11, 8, 3, 4, 0, 6};
int p[] = {1, 12};
auto whole = std::ranges::subrange(Iter1(a), Sent1(Iter1(a + 6)));
auto prefix = std::ranges::subrange(Iter2(p), Sent2(Iter2(p + 2)));
std::same_as<bool> decltype(auto) ret = std::ranges::starts_with(whole, prefix, [](int l, int r) { return l > r; });
assert(!ret);
}
}
// check that the projections are used
{
{
int a[] = {1, 3, 5, 1, 5, 6};
int p[] = {2, 3, 4};
std::same_as<bool> decltype(auto) ret = std::ranges::starts_with(
Iter1(a),
Sent1(Iter1(a + 6)),
Iter2(p),
Sent2(Iter2(p + 3)),
{},
[](int i) { return i + 3; },
[](int i) { return i * 2; });
assert(ret);
}
{
int a[] = {1, 3, 5, 1, 5, 6};
int p[] = {2, 3, 4};
auto whole = std::ranges::subrange(Iter1(a), Sent1(Iter1(a + 6)));
auto prefix = std::ranges::subrange(Iter2(p), Sent2(Iter2(p + 3)));
std::same_as<bool> decltype(auto) ret = std::ranges::starts_with(
whole, prefix, {}, [](int i) { return i + 3; }, [](int i) { return i * 2; });
assert(ret);
}
}
}
constexpr bool test() {
types::for_each(types::forward_iterator_list<int*>{}, []<class I2>() {
types::for_each(types::forward_iterator_list<int*>{}, []<class I1>() {
test_iterators<I1, I1, I2, I2>();
test_iterators<I1, sized_sentinel<I1>, I2, I2>();
test_iterators<I1, I1, I2, sized_sentinel<I2>>();
test_iterators<I1, sized_sentinel<I1>, I2, sized_sentinel<I2>>();
});
});
// check that std::invoke is used
{
struct S {
int i;
constexpr S identity() { return *this; }
constexpr bool compare(const S& s) { return i == s.i; }
};
{
S a[] = {{1}, {2}, {3}, {4}};
S p[] = {{1}, {2}};
auto ret = std::ranges::starts_with(a, a + 4, p, p + 2, &S::compare, &S::identity, &S::identity);
assert(ret);
}
{
S a[] = {{1}, {2}, {3}, {4}};
S p[] = {{1}, {2}};
auto ret = std::ranges::starts_with(a, p, &S::compare, &S::identity, &S::identity);
assert(ret);
}
}
return true;
}
int main(int, char**) {
test();
static_assert(test());
return 0;
}
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