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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
// UNSUPPORTED: libcpp-no-concepts
// UNSUPPORTED: gcc-10
// UNSUPPORTED: libcpp-has-no-incomplete-ranges
// std::ranges::empty
#include <ranges>
#include <cassert>
#include "test_macros.h"
#include "test_iterators.h"
using RangeEmptyT = decltype(std::ranges::empty);
using RangeSizeT = decltype(std::ranges::size);
static_assert(!std::is_invocable_v<RangeEmptyT, int[]>);
static_assert(!std::is_invocable_v<RangeEmptyT, int(&)[]>);
static_assert(!std::is_invocable_v<RangeEmptyT, int(&&)[]>);
static_assert( std::is_invocable_v<RangeEmptyT, int[1]>);
static_assert( std::is_invocable_v<RangeEmptyT, const int[1]>);
static_assert( std::is_invocable_v<RangeEmptyT, int (&&)[1]>);
static_assert( std::is_invocable_v<RangeEmptyT, int (&)[1]>);
static_assert( std::is_invocable_v<RangeEmptyT, const int (&)[1]>);
struct NonConstSizeAndEmpty {
int size();
bool empty();
};
static_assert(!std::is_invocable_v<RangeSizeT, const NonConstSizeAndEmpty&>);
static_assert(!std::is_invocable_v<RangeEmptyT, const NonConstSizeAndEmpty&>);
struct HasMemberAndFunction {
constexpr bool empty() const { return true; }
// We should never do ADL lookup for std::ranges::empty.
friend bool empty(const HasMemberAndFunction&) { return false; }
};
struct BadReturnType {
BadReturnType empty() { return {}; }
};
static_assert(!std::is_invocable_v<RangeEmptyT, BadReturnType>);
struct BoolConvertible {
constexpr operator bool() noexcept(false) { return true; }
};
struct BoolConvertibleReturnType {
constexpr BoolConvertible empty() noexcept { return {}; }
};
static_assert(!noexcept(std::ranges::empty(BoolConvertibleReturnType())));
constexpr bool testEmptyMember() {
HasMemberAndFunction a;
assert(std::ranges::empty(a) == true);
BoolConvertibleReturnType b;
assert(std::ranges::empty(b) == true);
return true;
}
struct SizeMember {
size_t size_;
constexpr size_t size() const { return size_; }
};
struct SizeFunction {
size_t size_;
friend constexpr size_t size(SizeFunction sf) { return sf.size_; }
};
constexpr bool testUsingRangesSize() {
SizeMember a{1};
assert(std::ranges::empty(a) == false);
SizeMember b{0};
assert(std::ranges::empty(b) == true);
SizeFunction c{1};
assert(std::ranges::empty(c) == false);
SizeFunction d{0};
assert(std::ranges::empty(d) == true);
return true;
}
struct other_forward_iterator : forward_iterator<int*> { };
struct sentinel {
constexpr bool operator==(std::input_or_output_iterator auto) const { return true; }
};
struct BeginEndNotSizedSentinel {
friend constexpr forward_iterator<int*> begin(BeginEndNotSizedSentinel) { return {}; }
friend constexpr sentinel end(BeginEndNotSizedSentinel) { return {}; }
};
static_assert(!std::is_invocable_v<RangeSizeT, BeginEndNotSizedSentinel&>);
struct InvalidMinusBeginEnd {
friend constexpr random_access_iterator<int*> begin(InvalidMinusBeginEnd) { return {}; }
friend constexpr sentinel end(InvalidMinusBeginEnd) { return {}; }
};
// Int is integer-like, but it is not other_forward_iterator's difference_type.
constexpr short operator-(sentinel, random_access_iterator<int*>) { return 2; }
constexpr short operator-(random_access_iterator<int*>, sentinel) { return 2; }
static_assert(!std::is_invocable_v<RangeSizeT, InvalidMinusBeginEnd&>);
// This type will use ranges::size.
struct IntPtrBeginAndEnd {
int buff[8];
constexpr int* begin() { return buff; }
constexpr int* end() { return buff + 8; }
};
static_assert(std::is_invocable_v<RangeSizeT, IntPtrBeginAndEnd&>);
// size is disabled here, and it isn't sized_sentinel_for, so we have to compare begin
// and end again.
struct DisabledSizeRangeWithBeginEnd {
friend constexpr forward_iterator<int*> begin(DisabledSizeRangeWithBeginEnd) { return {}; }
friend constexpr sentinel end(DisabledSizeRangeWithBeginEnd) { return {}; }
constexpr size_t size() const { return 1; }
};
template <>
inline constexpr bool std::ranges::disable_sized_range<DisabledSizeRangeWithBeginEnd> = true;
static_assert(!std::is_invocable_v<RangeSizeT, DisabledSizeRangeWithBeginEnd&>);
struct BeginEndAndEmpty {
int* begin();
int* end();
constexpr bool empty() { return true; }
};
struct BeginEndAndConstEmpty {
int* begin();
int* end();
constexpr bool empty() const { return true; }
};
constexpr bool testBeginEqualsEnd() {
BeginEndNotSizedSentinel a;
assert(std::ranges::empty(a) == true);
InvalidMinusBeginEnd b;
assert(std::ranges::empty(b) == true);
IntPtrBeginAndEnd c;
assert(std::ranges::empty(c) == false);
DisabledSizeRangeWithBeginEnd d;
assert(std::ranges::empty(d) == true);
BeginEndAndEmpty e;
assert(std::ranges::empty(e) == true);
BeginEndAndConstEmpty f;
assert(std::ranges::empty(f) == true);
assert(std::ranges::empty(std::as_const(f)) == true);
return true;
}
int main(int, char**) {
testEmptyMember();
static_assert(testEmptyMember());
testUsingRangesSize();
static_assert(testUsingRangesSize());
testBeginEqualsEnd();
static_assert(testBeginEqualsEnd());
return 0;
}
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