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// Copyright 2020 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "base/containers/checked_iterators.h"
#include <algorithm>
#include <iterator>
#include "base/check_op.h"
#include "base/ranges/algorithm.h"
#include "build/build_config.h"
#include "testing/gtest/include/gtest/gtest.h"
namespace base {
#if defined(__cpp_lib_ranges)
TEST(CheckedContiguousIterator, SatisfiesContiguousIteratorConcept) {
static_assert(std::contiguous_iterator<CheckedContiguousIterator<int>>);
}
#endif
// Checks that constexpr CheckedContiguousConstIterators can be compared at
// compile time.
TEST(CheckedContiguousIterator, StaticComparisonOperators) {
static constexpr int arr[] = {0};
constexpr CheckedContiguousConstIterator<int> begin(arr, arr, arr + 1);
constexpr CheckedContiguousConstIterator<int> end(arr, arr + 1, arr + 1);
static_assert(begin == begin, "");
static_assert(end == end, "");
static_assert(begin != end, "");
static_assert(end != begin, "");
static_assert(begin < end, "");
static_assert(begin <= begin, "");
static_assert(begin <= end, "");
static_assert(end <= end, "");
static_assert(end > begin, "");
static_assert(end >= end, "");
static_assert(end >= begin, "");
static_assert(begin >= begin, "");
}
// Checks that comparison between iterators and const iterators works in both
// directions.
TEST(CheckedContiguousIterator, ConvertingComparisonOperators) {
static int arr[] = {0};
CheckedContiguousIterator<int> begin(arr, arr, arr + 1);
CheckedContiguousConstIterator<int> cbegin(arr, arr, arr + 1);
CheckedContiguousIterator<int> end(arr, arr + 1, arr + 1);
CheckedContiguousConstIterator<int> cend(arr, arr + 1, arr + 1);
EXPECT_EQ(begin, cbegin);
EXPECT_EQ(cbegin, begin);
EXPECT_EQ(end, cend);
EXPECT_EQ(cend, end);
EXPECT_NE(begin, cend);
EXPECT_NE(cbegin, end);
EXPECT_NE(end, cbegin);
EXPECT_NE(cend, begin);
EXPECT_LT(begin, cend);
EXPECT_LT(cbegin, end);
EXPECT_LE(begin, cbegin);
EXPECT_LE(cbegin, begin);
EXPECT_LE(begin, cend);
EXPECT_LE(cbegin, end);
EXPECT_LE(end, cend);
EXPECT_LE(cend, end);
EXPECT_GT(end, cbegin);
EXPECT_GT(cend, begin);
EXPECT_GE(end, cend);
EXPECT_GE(cend, end);
EXPECT_GE(end, cbegin);
EXPECT_GE(cend, begin);
EXPECT_GE(begin, cbegin);
EXPECT_GE(cbegin, begin);
}
} // namespace base
#if defined(_LIBCPP_VERSION)
namespace {
// Helper template that wraps an iterator and disables its dereference and
// increment operations.
// Note: We don't simply delete these operations, because code using these
// operations still needs to compile, even though the codepath will never be
// taken at runtime. This will crash at runtime in case code does try to use
// these operations.
template <typename Iterator>
struct DisableDerefAndIncr : Iterator {
using Iterator::Iterator;
// NOLINTNEXTLINE(google-explicit-constructor)
constexpr DisableDerefAndIncr(const Iterator& iter) : Iterator(iter) {}
constexpr typename Iterator::reference operator*() {
CHECK(false);
return Iterator::operator*();
}
constexpr Iterator& operator++() {
CHECK(false);
return Iterator::operator++();
}
constexpr Iterator operator++(int i) {
CHECK(false);
return Iterator::operator++(i);
}
};
} // namespace
// Inherit `__libcpp_is_contiguous_iterator` and `pointer_traits`
// specializations from the base class.
// TODO(crbug.com/1284275): Remove when C++20 is on by default, as the use
// of `iterator_concept` should suffice.
_LIBCPP_BEGIN_NAMESPACE_STD
// TODO(crbug.com/1449299): https://reviews.llvm.org/D150801 renamed this from
// `__is_cpp17_contiguous_iterator` to `__libcpp_is_contiguous_iterator`. Clean
// up the old spelling after libc++ rolls.
template <typename Iter>
struct __is_cpp17_contiguous_iterator<DisableDerefAndIncr<Iter>>
: __is_cpp17_contiguous_iterator<Iter> {};
template <typename Iter>
struct __libcpp_is_contiguous_iterator<DisableDerefAndIncr<Iter>>
: __libcpp_is_contiguous_iterator<Iter> {};
template <typename Iter>
struct pointer_traits<DisableDerefAndIncr<Iter>> : pointer_traits<Iter> {};
_LIBCPP_END_NAMESPACE_STD
namespace base {
// Tests that using std::copy with CheckedContiguousIterator<int> results in an
// optimized code-path that does not invoke the iterator's dereference and
// increment operations. This would fail at runtime if std::copy was not
// optimized.
TEST(CheckedContiguousIterator, OptimizedCopy) {
using Iter = DisableDerefAndIncr<CheckedContiguousIterator<int>>;
int arr_in[5] = {1, 2, 3, 4, 5};
int arr_out[5];
Iter in_begin(std::begin(arr_in), std::end(arr_in));
Iter in_end(std::begin(arr_in), std::end(arr_in), std::end(arr_in));
Iter out_begin(std::begin(arr_out), std::end(arr_out));
Iter out_end = std::copy(in_begin, in_end, out_begin);
EXPECT_EQ(out_end, out_begin + (in_end - in_begin));
EXPECT_TRUE(ranges::equal(arr_in, arr_out));
}
} // namespace base
#endif
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