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// Copyright 2017 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/span.h"
#include <stdint.h>
#include <algorithm>
#include <concepts>
#include <iterator>
#include <memory>
#include <span>
#include <string>
#include <string_view>
#include <type_traits>
#include <utility>
#include <vector>
#include "base/compiler_specific.h"
#include "base/containers/adapters.h"
#include "base/containers/checked_iterators.h"
#include "base/debug/alias.h"
#include "base/memory/raw_span.h"
#include "base/numerics/byte_conversions.h"
#include "base/ranges/algorithm.h"
#include "base/test/gtest_util.h"
#include "testing/gmock/include/gmock/gmock.h"
#include "testing/gtest/include/gtest/gtest.h"
using ::testing::ElementsAre;
using ::testing::ElementsAreArray;
using ::testing::Eq;
using ::testing::Pointwise;
namespace base {
namespace {
// Tests for span(It, StrictNumeric<size_t>) deduction guide. These tests use a
// helper function to wrap the static_asserts, as most STL containers don't work
// well in a constexpr context. std::array<T, N> does, but base::span has
// specific overloads for std::array<T, n>, so that ends up being less helpful
// than it would initially appear.
//
// Another alternative would be to use std::declval, but that would be fairly
// verbose.
[[maybe_unused]] void TestDeductionGuides() {
// Tests for span(It, EndOrSize) deduction guide.
{
const std::vector<int> v;
static_assert(
std::is_same_v<decltype(span(v.cbegin(), v.size())), span<const int>>);
static_assert(
std::is_same_v<decltype(span(v.begin(), v.size())), span<const int>>);
static_assert(
std::is_same_v<decltype(span(v.data(), v.size())), span<const int>>);
}
{
std::vector<int> v;
static_assert(
std::is_same_v<decltype(span(v.cbegin(), v.size())), span<const int>>);
static_assert(
std::is_same_v<decltype(span(v.begin(), v.size())), span<int>>);
static_assert(
std::is_same_v<decltype(span(v.data(), v.size())), span<int>>);
}
{
const std::vector<int> v;
static_assert(
std::is_same_v<decltype(span(v.cbegin(), v.cend())), span<const int>>);
static_assert(
std::is_same_v<decltype(span(v.begin(), v.end())), span<const int>>);
}
{
std::vector<int> v;
static_assert(
std::is_same_v<decltype(span(v.cbegin(), v.cend())), span<const int>>);
static_assert(
std::is_same_v<decltype(span(v.begin(), v.end())), span<int>>);
}
// Tests for span(Range&&) deduction guide.
{
const int kArray[] = {1, 2, 3};
static_assert(std::is_same_v<decltype(span(kArray)), span<const int, 3>>);
}
{
int kArray[] = {1, 2, 3};
static_assert(std::is_same_v<decltype(span(kArray)), span<int, 3>>);
}
// We also deduce an rvalue array to make a fixed-span over const values,
// which matches the span<const T> constructor from an array.
static_assert(std::is_same_v<decltype(span({1, 2, 3})), span<const int, 3>>);
static_assert(
std::is_same_v<decltype(span(std::declval<std::array<const bool, 3>&>())),
span<const bool, 3>>);
static_assert(
std::is_same_v<decltype(span(std::declval<std::array<bool, 3>&>())),
span<bool, 3>>);
static_assert(
std::is_same_v<decltype(span(
std::declval<const std::array<const bool, 3>&>())),
span<const bool, 3>>);
static_assert(
std::is_same_v<decltype(span(
std::declval<const std::array<const bool, 3>&&>())),
span<const bool, 3>>);
static_assert(std::is_same_v<
decltype(span(std::declval<std::array<const bool, 3>&&>())),
span<const bool, 3>>);
static_assert(
std::is_same_v<decltype(span(std::declval<const std::array<bool, 3>&>())),
span<const bool, 3>>);
static_assert(std::is_same_v<
decltype(span(std::declval<const std::array<bool, 3>&&>())),
span<const bool, 3>>);
static_assert(
std::is_same_v<decltype(span(std::declval<std::array<bool, 3>&&>())),
span<const bool, 3>>);
static_assert(
std::is_same_v<decltype(span(std::declval<const std::string&>())),
span<const char>>);
static_assert(
std::is_same_v<decltype(span(std::declval<const std::string&&>())),
span<const char>>);
static_assert(
std::is_same_v<decltype(span(std::declval<std::string&>())), span<char>>);
static_assert(std::is_same_v<decltype(span(std::declval<std::string&&>())),
span<const char>>);
static_assert(
std::is_same_v<decltype(span(std::declval<const std::u16string&>())),
span<const char16_t>>);
static_assert(
std::is_same_v<decltype(span(std::declval<const std::u16string&&>())),
span<const char16_t>>);
static_assert(std::is_same_v<decltype(span(std::declval<std::u16string&>())),
span<char16_t>>);
static_assert(std::is_same_v<decltype(span(std::declval<std::u16string&&>())),
span<const char16_t>>);
static_assert(std::is_same_v<
decltype(span(std::declval<const std::array<float, 9>&>())),
span<const float, 9>>);
static_assert(std::is_same_v<
decltype(span(std::declval<const std::array<float, 9>&&>())),
span<const float, 9>>);
static_assert(
std::is_same_v<decltype(span(std::declval<std::array<float, 9>&>())),
span<float, 9>>);
static_assert(
std::is_same_v<decltype(span(std::declval<std::array<float, 9>&&>())),
span<const float, 9>>);
}
} // namespace
TEST(SpanTest, DefaultConstructor) {
span<int> dynamic_span;
EXPECT_EQ(nullptr, dynamic_span.data());
EXPECT_EQ(0u, dynamic_span.size());
constexpr span<int, 0> static_span;
static_assert(nullptr == static_span.data(), "");
static_assert(0u == static_span.size(), "");
}
TEST(SpanTest, ConstructFromDataAndSize) {
constexpr int* kNull = nullptr;
// SAFETY: zero size is correct when pointer argument is NULL.
constexpr span<int> UNSAFE_BUFFERS(empty_span(kNull, 0u));
EXPECT_TRUE(empty_span.empty());
EXPECT_EQ(nullptr, empty_span.data());
std::vector<int> vector = {1, 1, 2, 3, 5, 8};
// SAFETY: `vector.size()` describes valid portion of `vector.data()`.
span<int> UNSAFE_BUFFERS(dynamic_span(vector.data(), vector.size()));
EXPECT_EQ(vector.data(), dynamic_span.data());
EXPECT_EQ(vector.size(), dynamic_span.size());
for (size_t i = 0; i < dynamic_span.size(); ++i) {
EXPECT_EQ(vector[i], dynamic_span[i]);
}
// SAFETY: `vector.size()` describes valid portion of `vector.data()`.
span<int, 6> UNSAFE_BUFFERS(static_span(vector.data(), vector.size()));
EXPECT_EQ(vector.data(), static_span.data());
EXPECT_EQ(vector.size(), static_span.size());
for (size_t i = 0; i < static_span.size(); ++i) {
EXPECT_EQ(vector[i], static_span[i]);
}
}
TEST(SpanTest, ConstructFromDataAndZeroSize) {
char* nullptr_to_char = nullptr;
auto empty_span = UNSAFE_BUFFERS(span<char>(nullptr_to_char, 0u));
EXPECT_EQ(empty_span.size(), 0u);
EXPECT_EQ(empty_span.data(), nullptr);
EXPECT_TRUE(empty_span.empty());
// We expect a `DCHECK` to catch construction of a dangling span - let's cover
// this expectation in a test, so that future `//base` refactorings (e.g.
// maybe switching to `std::span`) won't just silently change of this aspect
// of span behavior.
EXPECT_DCHECK_DEATH({ UNSAFE_BUFFERS(span<char>(nullptr_to_char, 123u)); });
}
TEST(SpanTest, ConstructFromIterAndSize) {
constexpr int* kNull = nullptr;
// SAFETY: zero size is correct when pointer argument is NULL.
constexpr span<int> UNSAFE_BUFFERS(empty_span(kNull, 0u));
EXPECT_TRUE(empty_span.empty());
EXPECT_EQ(nullptr, empty_span.data());
std::vector<int> vector = {1, 1, 2, 3, 5, 8};
// SAFETY: `vector.size()` describes valid bytes following `vector.begin()`.
span<int> UNSAFE_BUFFERS(dynamic_span(vector.begin(), vector.size()));
EXPECT_EQ(vector.data(), dynamic_span.data());
EXPECT_EQ(vector.size(), dynamic_span.size());
for (size_t i = 0; i < dynamic_span.size(); ++i) {
EXPECT_EQ(vector[i], dynamic_span[i]);
}
// SAFETY: `vector.size()` describes valid bytes following `vector.begin()`.
span<int, 6> UNSAFE_BUFFERS(static_span(vector.begin(), vector.size()));
EXPECT_EQ(vector.data(), static_span.data());
EXPECT_EQ(vector.size(), static_span.size());
for (size_t i = 0; i < static_span.size(); ++i) {
EXPECT_EQ(vector[i], static_span[i]);
}
}
TEST(SpanTest, ConstructFromIterPair) {
constexpr int* kNull = nullptr;
// SAFETY: required for test, NULL range valid.
constexpr span<int> UNSAFE_BUFFERS(empty_span(kNull, kNull));
EXPECT_TRUE(empty_span.empty());
EXPECT_EQ(nullptr, empty_span.data());
std::vector<int> vector = {1, 1, 2, 3, 5, 8};
// SAFETY: `vector.size()` describes valid portion of `vector.data()`,
// thus one-half `vector.size()` is within this range.
span<int> UNSAFE_BUFFERS(
dynamic_span(vector.begin(), vector.begin() + vector.size() / 2));
EXPECT_EQ(vector.data(), dynamic_span.data());
EXPECT_EQ(vector.size() / 2, dynamic_span.size());
for (size_t i = 0; i < dynamic_span.size(); ++i) {
EXPECT_EQ(vector[i], dynamic_span[i]);
}
// SAFETY: `vector.size()` describes valid portion of `vector.data()`,
// thus one-half `vector.size()` is within this range.
span<int, 3> UNSAFE_BUFFERS(
static_span(vector.begin(), vector.begin() + vector.size() / 2));
EXPECT_EQ(vector.data(), static_span.data());
EXPECT_EQ(vector.size() / 2, static_span.size());
for (size_t i = 0; i < static_span.size(); ++i) {
EXPECT_EQ(vector[i], static_span[i]);
}
}
TEST(SpanTest, AllowedConversionsFromStdArray) {
// In the following assertions we use std::is_convertible_v<From, To>, which
// for non-void types is equivalent to checking whether the following
// expression is well-formed:
//
// T obj = std::declval<From>();
//
// In particular we are checking whether From is implicitly convertible to To,
// which also implies that To is explicitly constructible from From.
static_assert(
std::is_convertible_v<std::array<int, 3>&, base::span<int>>,
"Error: l-value reference to std::array<int> should be convertible to "
"base::span<int> with dynamic extent.");
static_assert(
std::is_convertible_v<std::array<int, 3>&, base::span<int, 3>>,
"Error: l-value reference to std::array<int> should be convertible to "
"base::span<int> with the same static extent.");
static_assert(
std::is_convertible_v<std::array<int, 3>&, base::span<const int>>,
"Error: l-value reference to std::array<int> should be convertible to "
"base::span<const int> with dynamic extent.");
static_assert(
std::is_convertible_v<std::array<int, 3>&, base::span<const int, 3>>,
"Error: l-value reference to std::array<int> should be convertible to "
"base::span<const int> with the same static extent.");
static_assert(
std::is_convertible_v<const std::array<int, 3>&, base::span<const int>>,
"Error: const l-value reference to std::array<int> should be "
"convertible to base::span<const int> with dynamic extent.");
static_assert(
std::is_convertible_v<const std::array<int, 3>&,
base::span<const int, 3>>,
"Error: const l-value reference to std::array<int> should be convertible "
"to base::span<const int> with the same static extent.");
static_assert(
std::is_convertible_v<std::array<const int, 3>&, base::span<const int>>,
"Error: l-value reference to std::array<const int> should be "
"convertible to base::span<const int> with dynamic extent.");
static_assert(
std::is_convertible_v<std::array<const int, 3>&,
base::span<const int, 3>>,
"Error: l-value reference to std::array<const int> should be convertible "
"to base::span<const int> with the same static extent.");
static_assert(
std::is_convertible_v<const std::array<const int, 3>&,
base::span<const int>>,
"Error: const l-value reference to std::array<const int> should be "
"convertible to base::span<const int> with dynamic extent.");
static_assert(
std::is_convertible_v<const std::array<const int, 3>&,
base::span<const int, 3>>,
"Error: const l-value reference to std::array<const int> should be "
"convertible to base::span<const int> with the same static extent.");
}
TEST(SpanTest, DisallowedConstructionsFromStdArray) {
// In the following assertions we use !std::is_constructible_v<T, Args>, which
// is equivalent to checking whether the following expression is malformed:
//
// T obj(std::declval<Args>()...);
//
// In particular we are checking that T is not explicitly constructible from
// Args, which also implies that T is not implicitly constructible from Args
// as well.
static_assert(
!std::is_constructible_v<base::span<int>, const std::array<int, 3>&>,
"Error: base::span<int> with dynamic extent should not be constructible "
"from const l-value reference to std::array<int>");
static_assert(
!std::is_constructible_v<base::span<int>, std::array<const int, 3>&>,
"Error: base::span<int> with dynamic extent should not be constructible "
"from l-value reference to std::array<const int>");
static_assert(
!std::is_constructible_v<base::span<int>,
const std::array<const int, 3>&>,
"Error: base::span<int> with dynamic extent should not be constructible "
"const from l-value reference to std::array<const int>");
static_assert(
!std::is_constructible_v<base::span<int, 2>, std::array<int, 3>&>,
"Error: base::span<int> with static extent should not be constructible "
"from l-value reference to std::array<int> with different extent");
static_assert(
!std::is_constructible_v<base::span<int, 4>, std::array<int, 3>&>,
"Error: base::span<int> with dynamic extent should not be constructible "
"from l-value reference to std::array<int> with different extent");
static_assert(
!std::is_constructible_v<base::span<int>, std::array<bool, 3>&>,
"Error: base::span<int> with dynamic extent should not be constructible "
"from l-value reference to std::array<bool>");
}
TEST(SpanTest, ConstructFromConstexprArray) {
static constexpr int kArray[] = {5, 4, 3, 2, 1};
constexpr span<const int> dynamic_span(kArray);
static_assert(kArray == dynamic_span.data(), "");
static_assert(std::size(kArray) == dynamic_span.size(), "");
static_assert(kArray[0] == dynamic_span[0], "");
static_assert(kArray[1] == dynamic_span[1], "");
static_assert(kArray[2] == dynamic_span[2], "");
static_assert(kArray[3] == dynamic_span[3], "");
static_assert(kArray[4] == dynamic_span[4], "");
constexpr span<const int, std::size(kArray)> static_span(kArray);
static_assert(kArray == static_span.data(), "");
static_assert(std::size(kArray) == static_span.size(), "");
static_assert(kArray[0] == static_span[0], "");
static_assert(kArray[1] == static_span[1], "");
static_assert(kArray[2] == static_span[2], "");
static_assert(kArray[3] == static_span[3], "");
static_assert(kArray[4] == static_span[4], "");
}
TEST(SpanTest, ConstructFromArray) {
int array[] = {5, 4, 3, 2, 1};
span<const int> const_span = array;
EXPECT_EQ(array, const_span.data());
EXPECT_THAT(const_span, ElementsAreArray(array));
span<int> dynamic_span = array;
EXPECT_EQ(array, dynamic_span.data());
EXPECT_THAT(dynamic_span, ElementsAreArray(array));
span<int, std::size(array)> static_span = array;
EXPECT_EQ(array, static_span.data());
EXPECT_EQ(std::size(array), static_span.size());
EXPECT_THAT(static_span, ElementsAreArray(array));
[](span<const int> dynamic_span) {
EXPECT_EQ(dynamic_span.size(), 5u);
EXPECT_EQ(dynamic_span[0u], 5);
EXPECT_EQ(dynamic_span[4u], 1);
}({{5, 4, 3, 2, 1}});
[](span<const int, 5u> static_span) {
EXPECT_EQ(static_span.size(), 5u);
EXPECT_EQ(static_span[0u], 5);
EXPECT_EQ(static_span[4u], 1);
}({{5, 4, 3, 2, 1}});
}
TEST(SpanTest, ConstructFromVolatileArray) {
static volatile int array[] = {5, 4, 3, 2, 1};
span<const volatile int> const_span(array);
static_assert(std::is_same_v<decltype(&const_span[1]), const volatile int*>);
static_assert(
std::is_same_v<decltype(const_span.data()), const volatile int*>);
EXPECT_EQ(array, const_span.data());
EXPECT_EQ(std::size(array), const_span.size());
for (size_t i = 0; i < const_span.size(); ++i) {
// SAFETY: `const_span` is the same size as `array` per previous
// EXPECT_EQ(), and const_span.size() describes the valid portion of
// const span, so indexing `array` at the same place is valid.
EXPECT_EQ(UNSAFE_BUFFERS(array[i]), const_span[i]);
}
span<volatile int> dynamic_span(array);
static_assert(std::is_same_v<decltype(&dynamic_span[1]), volatile int*>);
static_assert(std::is_same_v<decltype(dynamic_span.data()), volatile int*>);
EXPECT_EQ(array, dynamic_span.data());
EXPECT_EQ(std::size(array), dynamic_span.size());
for (size_t i = 0; i < dynamic_span.size(); ++i) {
// SAFETY: `dynamic_span` is the same size as `array` per previous
// EXPECT_EQ(), and `dynamic_span.size()` describes the valid portion of
// `dynamic_span`, so indexing `array` at the same place is valid.
EXPECT_EQ(UNSAFE_BUFFERS(array[i]), dynamic_span[i]);
}
span<volatile int, std::size(array)> static_span(array);
static_assert(std::is_same_v<decltype(&static_span[1]), volatile int*>);
static_assert(std::is_same_v<decltype(static_span.data()), volatile int*>);
EXPECT_EQ(array, static_span.data());
EXPECT_EQ(std::size(array), static_span.size());
for (size_t i = 0; i < static_span.size(); ++i) {
// SAFETY: `static_span` is the same size as `array` per previous
// EXPECT_EQ(), and `static_span.size()` describes the valid portion of
// `static_span`, so indexing `array` at the same place is valid.
EXPECT_EQ(UNSAFE_BUFFERS(array[i]), static_span[i]);
}
}
TEST(SpanTest, ConstructFromStdArray) {
// Note: Constructing a constexpr span from a constexpr std::array does not
// work prior to C++17 due to non-constexpr std::array::data.
std::array<int, 5> array = {{5, 4, 3, 2, 1}};
span<const int> const_span(array);
EXPECT_EQ(array.data(), const_span.data());
EXPECT_EQ(array.size(), const_span.size());
for (size_t i = 0; i < const_span.size(); ++i) {
EXPECT_EQ(array[i], const_span[i]);
}
span<int> dynamic_span(array);
EXPECT_EQ(array.data(), dynamic_span.data());
EXPECT_EQ(array.size(), dynamic_span.size());
for (size_t i = 0; i < dynamic_span.size(); ++i) {
EXPECT_EQ(array[i], dynamic_span[i]);
}
span<int, std::size(array)> static_span(array);
EXPECT_EQ(array.data(), static_span.data());
EXPECT_EQ(array.size(), static_span.size());
for (size_t i = 0; i < static_span.size(); ++i) {
EXPECT_EQ(array[i], static_span[i]);
}
}
TEST(SpanTest, ConstructFromInitializerList) {
std::initializer_list<int> il = {1, 1, 2, 3, 5, 8};
span<const int> const_span(il);
EXPECT_EQ(il.begin(), const_span.data());
EXPECT_EQ(il.size(), const_span.size());
for (size_t i = 0; i < const_span.size(); ++i) {
// SAFETY: `il.begin()` is valid to index up to `il.size()`, and
// `il.size()` equals `const_span.size()`, so `il.begin()` is valid
// to index up to `const_span.size()` per above loop condition.
EXPECT_EQ(UNSAFE_BUFFERS(il.begin()[i]), const_span[i]);
}
// SAFETY: [il.begin()..il.end()) is a valid range over `il`.
span<const int, 6> UNSAFE_BUFFERS(static_span(il.begin(), il.end()));
EXPECT_EQ(il.begin(), static_span.data());
EXPECT_EQ(il.size(), static_span.size());
for (size_t i = 0; i < static_span.size(); ++i) {
// SAFETY: `il.begin()` is valid to index up to `il.size()`, and
// `il.size()` equals `static_span.size()`, so `il.begin()` is valid
// to index up to `static_span.size()` per above loop condition.
EXPECT_EQ(UNSAFE_BUFFERS(il.begin()[i]), static_span[i]);
}
}
TEST(SpanTest, ConstructFromStdString) {
std::string str = "foobar";
span<const char> const_span(str);
EXPECT_EQ(str.data(), const_span.data());
EXPECT_EQ(str.size(), const_span.size());
for (size_t i = 0; i < const_span.size(); ++i) {
EXPECT_EQ(str[i], const_span[i]);
}
span<char> dynamic_span(str);
EXPECT_EQ(str.data(), dynamic_span.data());
EXPECT_EQ(str.size(), dynamic_span.size());
for (size_t i = 0; i < dynamic_span.size(); ++i) {
EXPECT_EQ(str[i], dynamic_span[i]);
}
// SAFETY: `str.size()` describes the valid portion of `str.data()` prior
// to the terminating NUL.
span<char, 6> UNSAFE_BUFFERS(static_span(str.data(), str.size()));
EXPECT_EQ(str.data(), static_span.data());
EXPECT_EQ(str.size(), static_span.size());
for (size_t i = 0; i < static_span.size(); ++i) {
EXPECT_EQ(str[i], static_span[i]);
}
}
TEST(SpanTest, ConstructFromConstContainer) {
const std::vector<int> vector = {1, 1, 2, 3, 5, 8};
span<const int> const_span(vector);
EXPECT_EQ(vector.data(), const_span.data());
EXPECT_EQ(vector.size(), const_span.size());
for (size_t i = 0; i < const_span.size(); ++i) {
EXPECT_EQ(vector[i], const_span[i]);
}
// SAFETY: `vector.size()` describes valid portion of `vector.data()`.
span<const int, 6> UNSAFE_BUFFERS(static_span(vector.data(), vector.size()));
EXPECT_EQ(vector.data(), static_span.data());
EXPECT_EQ(vector.size(), static_span.size());
for (size_t i = 0; i < static_span.size(); ++i) {
EXPECT_EQ(vector[i], static_span[i]);
}
}
TEST(SpanTest, ConstructFromContainer) {
std::vector<int> vector = {1, 1, 2, 3, 5, 8};
span<const int> const_span(vector);
EXPECT_EQ(vector.data(), const_span.data());
EXPECT_EQ(vector.size(), const_span.size());
for (size_t i = 0; i < const_span.size(); ++i) {
EXPECT_EQ(vector[i], const_span[i]);
}
span<int> dynamic_span(vector);
EXPECT_EQ(vector.data(), dynamic_span.data());
EXPECT_EQ(vector.size(), dynamic_span.size());
for (size_t i = 0; i < dynamic_span.size(); ++i) {
EXPECT_EQ(vector[i], dynamic_span[i]);
}
// SAFETY: vector.size() describes valid portion of vector.data().
span<int, 6> UNSAFE_BUFFERS(static_span(vector.data(), vector.size()));
EXPECT_EQ(vector.data(), static_span.data());
EXPECT_EQ(vector.size(), static_span.size());
for (size_t i = 0; i < static_span.size(); ++i) {
EXPECT_EQ(vector[i], static_span[i]);
}
}
TEST(SpanTest, ConstructFromRange) {
struct Range {
using iterator = base::span<const int>::iterator;
iterator begin() const { return base::span(arr_).begin(); }
iterator end() const { return base::span(arr_).end(); }
std::array<const int, 3u> arr_ = {1, 2, 3};
};
static_assert(std::ranges::contiguous_range<Range>);
{
Range r;
auto s = base::span(r);
static_assert(std::same_as<decltype(s), base::span<const int>>);
EXPECT_EQ(s, base::span({1, 2, 3}));
// Implicit from modern range with dynamic size to dynamic span.
base::span<const int> imp = r;
EXPECT_EQ(imp, base::span({1, 2, 3}));
}
{
Range r;
auto s = base::span<const int, 3u>(r);
EXPECT_EQ(s, base::span({1, 2, 3}));
// Explicit from modern range with dynamic size to fixed span.
static_assert(!std::convertible_to<decltype(r), base::span<const int, 3u>>);
base::span<const int, 3u> imp(r);
EXPECT_EQ(imp, base::span({1, 2, 3}));
}
struct LegacyRange {
const int* data() const { return arr_.data(); }
size_t size() const { return arr_.size(); }
std::array<const int, 3u> arr_ = {1, 2, 3};
};
static_assert(!std::ranges::contiguous_range<LegacyRange>);
static_assert(base::internal::LegacyRange<LegacyRange>);
{
LegacyRange r;
auto s = base::span(r);
static_assert(std::same_as<decltype(s), base::span<const int>>);
EXPECT_EQ(s, base::span({1, 2, 3}));
// Implicit from legacy range with dynamic size to dynamic span.
base::span<const int> imp = r;
EXPECT_EQ(imp, base::span({1, 2, 3}));
}
{
LegacyRange r;
auto s = base::span<const int, 3u>(r);
EXPECT_EQ(s, base::span({1, 2, 3}));
// Explicit from legacy range with dynamic size to fixed span.
static_assert(!std::convertible_to<decltype(r), base::span<const int, 3u>>);
base::span<const int, 3> imp(r);
EXPECT_EQ(imp, base::span({1, 2, 3}));
}
using FixedRange = const std::array<int, 3>;
static_assert(std::ranges::contiguous_range<FixedRange>);
static_assert(std::ranges::sized_range<FixedRange>);
{
FixedRange r = {1, 2, 3};
auto s = base::span(r);
static_assert(std::same_as<decltype(s), base::span<const int, 3>>);
EXPECT_EQ(s, base::span({1, 2, 3}));
// Implicit from fixed size to dynamic span.
base::span<const int> imp = r;
EXPECT_EQ(imp, base::span({1, 2, 3}));
}
{
FixedRange r = {1, 2, 3};
auto s = base::span<const int, 3u>(r);
EXPECT_EQ(s, base::span({1, 2, 3}));
// Implicit from fixed size to fixed span.
base::span<const int, 3u> imp = r;
EXPECT_EQ(imp, base::span({1, 2, 3}));
}
// Construction from std::vectors.
{
// Implicit.
static_assert(std::convertible_to<const std::vector<int>, span<const int>>);
const std::vector<int> i{1, 2, 3};
span<const int> s = i;
EXPECT_EQ(s, i);
}
{
// Explicit.
static_assert(
!std::convertible_to<const std::vector<int>, span<const int, 3u>>);
static_assert(
std::constructible_from<span<const int, 3u>, const std::vector<int>>);
const std::vector<int> i{1, 2, 3};
span<const int, 3u> s(i);
EXPECT_EQ(s, base::span(i));
}
// vector<bool> is special and can't be converted to a span since it does not
// actually hold an array of `bool`.
static_assert(
!std::constructible_from<span<const bool>, const std::vector<bool>>);
static_assert(
!std::constructible_from<span<const bool, 3u>, const std::vector<bool>>);
}
TEST(SpanTest, FromRefOfMutableStackVariable) {
int x = 123;
auto s = span_from_ref(x);
static_assert(std::is_same_v<decltype(s), span<int, 1u>>);
EXPECT_EQ(&x, s.data());
EXPECT_EQ(1u, s.size());
EXPECT_EQ(sizeof(int), s.size_bytes());
EXPECT_EQ(123, s[0]);
s[0] = 456;
EXPECT_EQ(456, x);
EXPECT_EQ(456, s[0]);
auto b = byte_span_from_ref(x);
static_assert(std::is_same_v<decltype(b), span<uint8_t, sizeof(int)>>);
EXPECT_EQ(reinterpret_cast<uint8_t*>(&x), b.data());
EXPECT_EQ(sizeof(int), b.size());
}
TEST(SpanTest, FromRefOfConstStackVariable) {
const int x = 123;
auto s = span_from_ref(x);
static_assert(std::is_same_v<decltype(s), span<const int, 1u>>);
EXPECT_EQ(&x, s.data());
EXPECT_EQ(1u, s.size());
EXPECT_EQ(sizeof(int), s.size_bytes());
EXPECT_EQ(123, s[0]);
auto b = byte_span_from_ref(x);
static_assert(std::is_same_v<decltype(b), span<const uint8_t, sizeof(int)>>);
EXPECT_EQ(reinterpret_cast<const uint8_t*>(&x), b.data());
EXPECT_EQ(sizeof(int), b.size());
}
TEST(SpanTest, FromCString) {
// No terminating null, size known at compile time.
{
auto s = base::span_from_cstring("hello");
static_assert(std::same_as<decltype(s), span<const char, 5u>>);
EXPECT_EQ(s[0u], 'h');
EXPECT_EQ(s[1u], 'e');
EXPECT_EQ(s[4u], 'o');
}
// No terminating null, size not known at compile time. string_view loses
// the size.
{
auto s = base::span(std::string_view("hello"));
static_assert(std::same_as<decltype(s), span<const char>>);
EXPECT_EQ(s[0u], 'h');
EXPECT_EQ(s[1u], 'e');
EXPECT_EQ(s[4u], 'o');
EXPECT_EQ(s.size(), 5u);
}
// Includes the terminating null, size known at compile time.
{
auto s = base::span_with_nul_from_cstring("hello");
static_assert(std::same_as<decltype(s), span<const char, 6u>>);
EXPECT_EQ(s[0u], 'h');
EXPECT_EQ(s[1u], 'e');
EXPECT_EQ(s[4u], 'o');
EXPECT_EQ(s[5u], '\0');
}
// No terminating null, size known at compile time. Converted to a span of
// uint8_t bytes.
{
auto s = base::byte_span_from_cstring("hello");
static_assert(std::same_as<decltype(s), span<const uint8_t, 5u>>);
EXPECT_EQ(s[0u], 'h');
EXPECT_EQ(s[1u], 'e');
EXPECT_EQ(s[4u], 'o');
}
// Includes the terminating null, size known at compile time. Converted to a
// span of uint8_t bytes.
{
auto s = base::byte_span_with_nul_from_cstring("hello");
static_assert(std::same_as<decltype(s), span<const uint8_t, 6u>>);
EXPECT_EQ(s[0u], 'h');
EXPECT_EQ(s[1u], 'e');
EXPECT_EQ(s[4u], 'o');
EXPECT_EQ(s[5u], '\0');
}
}
TEST(SpanTest, FromCStringEmpty) {
// No terminating null, size known at compile time.
{
auto s = base::span_from_cstring("");
static_assert(std::same_as<decltype(s), span<const char, 0u>>);
EXPECT_EQ(s.size(), 0u);
}
// No terminating null, size not known at compile time. string_view loses
// the size.
{
auto s = base::span(std::string_view(""));
static_assert(std::same_as<decltype(s), span<const char>>);
EXPECT_EQ(s.size(), 0u);
}
// Includes the terminating null, size known at compile time.
{
auto s = base::span_with_nul_from_cstring("");
static_assert(std::same_as<decltype(s), span<const char, 1u>>);
ASSERT_EQ(s.size(), 1u);
EXPECT_EQ(s[0u], '\0');
}
// No terminating null, size known at compile time. Converted to a span of
// uint8_t bytes.
{
auto s = base::byte_span_from_cstring("");
static_assert(std::same_as<decltype(s), span<const uint8_t, 0u>>);
ASSERT_EQ(s.size(), 0u);
}
// Includes the terminating null, size known at compile time. Converted to a
// span of uint8_t bytes.
{
auto s = base::byte_span_with_nul_from_cstring("");
static_assert(std::same_as<decltype(s), span<const uint8_t, 1u>>);
ASSERT_EQ(s.size(), 1u);
EXPECT_EQ(s[0u], '\0');
}
}
TEST(SpanTest, FromCStringEmbeddedNul) {
// No terminating null, size known at compile time.
{
auto s = base::span_from_cstring("h\0\0\0o");
static_assert(std::same_as<decltype(s), span<const char, 5u>>);
EXPECT_THAT(s, ElementsAre('h', '\0', '\0', '\0', 'o'));
}
// No terminating null, size not known at compile time. string_view loses
// the size, and stops at embedded NUL. Beware.
{
auto s = base::span(std::string_view("h\0\0\0o"));
static_assert(std::same_as<decltype(s), span<const char>>);
EXPECT_THAT(s, ElementsAre('h'));
}
// Includes the terminating null, size known at compile time.
{
auto s = base::span_with_nul_from_cstring("h\0\0\0o");
static_assert(std::same_as<decltype(s), span<const char, 6u>>);
EXPECT_THAT(s, ElementsAre('h', '\0', '\0', '\0', 'o', '\0'));
}
// No terminating null, size known at compile time. Converted to a span of
// uint8_t bytes.
{
auto s = base::byte_span_from_cstring("h\0\0\0o");
static_assert(std::same_as<decltype(s), span<const uint8_t, 5u>>);
EXPECT_THAT(s, ElementsAre('h', '\0', '\0', '\0', 'o'));
}
// Includes the terminating null, size known at compile time. Converted to a
// span of uint8_t bytes.
{
auto s = base::byte_span_with_nul_from_cstring("h\0\0\0o");
static_assert(std::same_as<decltype(s), span<const uint8_t, 6u>>);
EXPECT_THAT(s, ElementsAre('h', '\0', '\0', '\0', 'o', '\0'));
}
}
TEST(SpanTest, FromCStringOtherTypes) {
{
auto s = base::span_from_cstring("hello");
static_assert(std::same_as<decltype(s), span<const char, 5u>>);
EXPECT_EQ(s[0u], 'h');
EXPECT_EQ(s[1u], 'e');
EXPECT_EQ(s[4u], 'o');
}
{
auto s = base::span_from_cstring(L"hello");
static_assert(std::same_as<decltype(s), span<const wchar_t, 5u>>);
EXPECT_EQ(s[0u], L'h');
EXPECT_EQ(s[1u], L'e');
EXPECT_EQ(s[4u], L'o');
}
{
auto s = base::span_from_cstring(u"hello");
static_assert(std::same_as<decltype(s), span<const char16_t, 5u>>);
EXPECT_EQ(s[0u], u'h');
EXPECT_EQ(s[1u], u'e');
EXPECT_EQ(s[4u], u'o');
}
{
auto s = base::span_from_cstring(U"hello");
static_assert(std::same_as<decltype(s), span<const char32_t, 5u>>);
EXPECT_EQ(s[0u], U'h');
EXPECT_EQ(s[1u], U'e');
EXPECT_EQ(s[4u], U'o');
}
}
TEST(SpanTest, ConvertNonConstIntegralToConst) {
std::vector<int> vector = {1, 1, 2, 3, 5, 8};
// SAFETY: `vector.size()` describes valid portion of `vector.data()`.
span<int> UNSAFE_BUFFERS(int_span(vector.data(), vector.size()));
span<const int> const_span(int_span);
EXPECT_EQ(int_span.size(), const_span.size());
EXPECT_THAT(const_span, Pointwise(Eq(), int_span));
// SAFETY: `vector.size()` describes valid portion of `vector.data()`.
span<int, 6> UNSAFE_BUFFERS(static_int_span(vector.data(), vector.size()));
span<const int, 6> static_const_span(static_int_span);
EXPECT_THAT(static_const_span, Pointwise(Eq(), static_int_span));
}
TEST(SpanTest, ConvertNonConstPointerToConst) {
auto a = std::make_unique<int>(11);
auto b = std::make_unique<int>(22);
auto c = std::make_unique<int>(33);
std::vector<int*> vector = {a.get(), b.get(), c.get()};
span<int*> non_const_pointer_span(vector);
EXPECT_THAT(non_const_pointer_span, Pointwise(Eq(), vector));
span<int* const> const_pointer_span(non_const_pointer_span);
EXPECT_THAT(const_pointer_span, Pointwise(Eq(), non_const_pointer_span));
// Note: no test for conversion from span<int> to span<const int*>, since that
// would imply a conversion from int** to const int**, which is unsafe.
//
// Note: no test for conversion from span<int*> to span<const int* const>,
// due to CWG Defect 330:
// http://open-std.org/JTC1/SC22/WG21/docs/cwg_defects.html#330
// SAFETY: `vector.size()` describes valid portion of `vector.data()`.
span<int*, 3> UNSAFE_BUFFERS(
static_non_const_pointer_span(vector.data(), vector.size()));
EXPECT_THAT(static_non_const_pointer_span, Pointwise(Eq(), vector));
span<int* const, 3> static_const_pointer_span(static_non_const_pointer_span);
EXPECT_THAT(static_const_pointer_span,
Pointwise(Eq(), static_non_const_pointer_span));
}
TEST(SpanTest, ConvertBetweenEquivalentTypes) {
std::vector<int32_t> vector = {2, 4, 8, 16, 32};
span<int32_t> int32_t_span(vector);
span<int> converted_span(int32_t_span);
EXPECT_EQ(int32_t_span.data(), converted_span.data());
EXPECT_EQ(int32_t_span.size(), converted_span.size());
// SAFETY: `vector.size()` describes valid portion of `vector.data()`.
span<int32_t, 5> UNSAFE_BUFFERS(
static_int32_t_span(vector.data(), vector.size()));
span<int, 5> static_converted_span(static_int32_t_span);
EXPECT_EQ(static_int32_t_span.data(), static_converted_span.data());
EXPECT_EQ(static_int32_t_span.size(), static_converted_span.size());
}
TEST(SpanTest, TemplatedFirst) {
static constexpr int array[] = {1, 2, 3};
constexpr span<const int, 3> span(array);
{
constexpr auto subspan = span.first<0>();
static_assert(span.data() == subspan.data(), "");
static_assert(0u == subspan.size(), "");
static_assert(0u == decltype(subspan)::extent, "");
}
{
constexpr auto subspan = span.first<1>();
static_assert(span.data() == subspan.data(), "");
static_assert(1u == subspan.size(), "");
static_assert(1u == decltype(subspan)::extent, "");
static_assert(1 == subspan[0], "");
}
{
constexpr auto subspan = span.first<2>();
static_assert(span.data() == subspan.data(), "");
static_assert(2u == subspan.size(), "");
static_assert(2u == decltype(subspan)::extent, "");
static_assert(1 == subspan[0], "");
static_assert(2 == subspan[1], "");
}
{
constexpr auto subspan = span.first<3>();
static_assert(span.data() == subspan.data(), "");
static_assert(3u == subspan.size(), "");
static_assert(3u == decltype(subspan)::extent, "");
static_assert(1 == subspan[0], "");
static_assert(2 == subspan[1], "");
static_assert(3 == subspan[2], "");
}
}
TEST(SpanTest, TemplatedLast) {
static constexpr int array[] = {1, 2, 3};
constexpr span<const int, 3> span(array);
{
constexpr auto subspan = span.last<0>();
// SAFETY: static_assert() doesn't execute code at runtime.
static_assert(UNSAFE_BUFFERS(span.data() + 3) == subspan.data(), "");
static_assert(0u == subspan.size(), "");
static_assert(0u == decltype(subspan)::extent, "");
}
{
constexpr auto subspan = span.last<1>();
// SAFETY: static_assert() doesn't execute code at runtime.
static_assert(UNSAFE_BUFFERS(span.data() + 2) == subspan.data(), "");
static_assert(1u == subspan.size(), "");
static_assert(1u == decltype(subspan)::extent, "");
static_assert(3 == subspan[0], "");
}
{
constexpr auto subspan = span.last<2>();
// SAFETY: static_assert() doesn't execute code at runtime.
static_assert(UNSAFE_BUFFERS(span.data() + 1) == subspan.data(), "");
static_assert(2u == subspan.size(), "");
static_assert(2u == decltype(subspan)::extent, "");
static_assert(2 == subspan[0], "");
static_assert(3 == subspan[1], "");
}
{
constexpr auto subspan = span.last<3>();
static_assert(span.data() == subspan.data(), "");
static_assert(3u == subspan.size(), "");
static_assert(3u == decltype(subspan)::extent, "");
static_assert(1 == subspan[0], "");
static_assert(2 == subspan[1], "");
static_assert(3 == subspan[2], "");
}
}
TEST(SpanTest, TemplatedSubspan) {
static constexpr int array[] = {1, 2, 3};
constexpr span<const int, 3> span(array);
{
constexpr auto subspan = span.subspan<0>();
static_assert(span.data() == subspan.data(), "");
static_assert(3u == subspan.size(), "");
static_assert(3u == decltype(subspan)::extent, "");
static_assert(1 == subspan[0], "");
static_assert(2 == subspan[1], "");
static_assert(3 == subspan[2], "");
}
{
constexpr auto subspan = span.subspan<1>();
// SAFETY: static_assert() doesn't execute code at runtime.
static_assert(UNSAFE_BUFFERS(span.data() + 1) == subspan.data(), "");
static_assert(2u == subspan.size(), "");
static_assert(2u == decltype(subspan)::extent, "");
static_assert(2 == subspan[0], "");
static_assert(3 == subspan[1], "");
}
{
constexpr auto subspan = span.subspan<2>();
// SAFETY: static_assert() doesn't execute code at runtime.
static_assert(UNSAFE_BUFFERS(span.data() + 2) == subspan.data(), "");
static_assert(1u == subspan.size(), "");
static_assert(1u == decltype(subspan)::extent, "");
static_assert(3 == subspan[0], "");
}
{
constexpr auto subspan = span.subspan<3>();
// SAFETY: static_assert() doesn't execute code at runtime.
static_assert(UNSAFE_BUFFERS(span.data() + 3) == subspan.data(), "");
static_assert(0u == subspan.size(), "");
static_assert(0u == decltype(subspan)::extent, "");
}
{
constexpr auto subspan = span.subspan<0, 0>();
static_assert(span.data() == subspan.data(), "");
static_assert(0u == subspan.size(), "");
static_assert(0u == decltype(subspan)::extent, "");
}
{
constexpr auto subspan = span.subspan<1, 0>();
// SAFETY: static_assert() doesn't execute code at runtime.
static_assert(UNSAFE_BUFFERS(span.data() + 1) == subspan.data(), "");
static_assert(0u == subspan.size(), "");
static_assert(0u == decltype(subspan)::extent, "");
}
{
constexpr auto subspan = span.subspan<2, 0>();
// SAFETY: static_assert() doesn't execute code at runtime.
static_assert(UNSAFE_BUFFERS(span.data() + 2) == subspan.data(), "");
static_assert(0u == subspan.size(), "");
static_assert(0u == decltype(subspan)::extent, "");
}
{
constexpr auto subspan = span.subspan<0, 1>();
static_assert(span.data() == subspan.data(), "");
static_assert(1u == subspan.size(), "");
static_assert(1u == decltype(subspan)::extent, "");
static_assert(1 == subspan[0], "");
}
{
constexpr auto subspan = span.subspan<1, 1>();
// SAFETY: static_assert() doesn't execute code at runtime.
static_assert(UNSAFE_BUFFERS(span.data() + 1) == subspan.data(), "");
static_assert(1u == subspan.size(), "");
static_assert(1u == decltype(subspan)::extent, "");
static_assert(2 == subspan[0], "");
}
{
constexpr auto subspan = span.subspan<2, 1>();
// SAFETY: static_assert() doesn't execute code at runtime.
static_assert(UNSAFE_BUFFERS(span.data() + 2) == subspan.data(), "");
static_assert(1u == subspan.size(), "");
static_assert(1u == decltype(subspan)::extent, "");
static_assert(3 == subspan[0], "");
}
{
constexpr auto subspan = span.subspan<0, 2>();
static_assert(span.data() == subspan.data(), "");
static_assert(2u == subspan.size(), "");
static_assert(2u == decltype(subspan)::extent, "");
static_assert(1 == subspan[0], "");
static_assert(2 == subspan[1], "");
}
{
constexpr auto subspan = span.subspan<1, 2>();
// SAFETY: static_assert() doesn't execute code at runtime.
static_assert(UNSAFE_BUFFERS(span.data() + 1) == subspan.data(), "");
static_assert(2u == subspan.size(), "");
static_assert(2u == decltype(subspan)::extent, "");
static_assert(2 == subspan[0], "");
static_assert(3 == subspan[1], "");
}
{
constexpr auto subspan = span.subspan<0, 3>();
static_assert(span.data() == subspan.data(), "");
static_assert(3u == subspan.size(), "");
static_assert(3u == decltype(subspan)::extent, "");
static_assert(1 == subspan[0], "");
static_assert(2 == subspan[1], "");
static_assert(3 == subspan[2], "");
}
}
TEST(SpanTest, SubscriptedBeginIterator) {
std::array<int, 3> array = {1, 2, 3};
span<const int> const_span(array);
for (size_t i = 0; i < const_span.size(); ++i) {
// SAFETY: The range starting at `const_span.begin()` is valid up
// to `const_span.size()`.
EXPECT_EQ(array[i], UNSAFE_BUFFERS(const_span.begin()[i]));
}
span<int> mutable_span(array);
for (size_t i = 0; i < mutable_span.size(); ++i) {
// SAFETY: The range starting at `mutable_span.begin()` is valid up
// to `mutable_span.size()`.
EXPECT_EQ(array[i], UNSAFE_BUFFERS(mutable_span.begin()[i]));
}
}
TEST(SpanTest, TemplatedFirstOnDynamicSpan) {
int array[] = {1, 2, 3};
span<const int> span(array);
{
auto subspan = span.first<0>();
EXPECT_EQ(span.data(), subspan.data());
EXPECT_EQ(0u, subspan.size());
static_assert(0u == decltype(subspan)::extent, "");
}
{
auto subspan = span.first<1>();
EXPECT_EQ(span.data(), subspan.data());
EXPECT_EQ(1u, subspan.size());
static_assert(1u == decltype(subspan)::extent, "");
EXPECT_EQ(1, subspan[0]);
}
{
auto subspan = span.first<2>();
EXPECT_EQ(span.data(), subspan.data());
EXPECT_EQ(2u, subspan.size());
static_assert(2u == decltype(subspan)::extent, "");
EXPECT_EQ(1, subspan[0]);
EXPECT_EQ(2, subspan[1]);
}
{
auto subspan = span.first<3>();
EXPECT_EQ(span.data(), subspan.data());
EXPECT_EQ(3u, subspan.size());
static_assert(3u == decltype(subspan)::extent, "");
EXPECT_EQ(1, subspan[0]);
EXPECT_EQ(2, subspan[1]);
EXPECT_EQ(3, subspan[2]);
}
}
TEST(SpanTest, TemplatedLastOnDynamicSpan) {
int array[] = {1, 2, 3};
span<int> span(array);
{
auto subspan = span.last<0>();
// `array` has three elmenents, so `span` has three elements, so
// `span.data() + 3` points to one byte beyond the object as allowed
// per standards.
EXPECT_EQ(UNSAFE_BUFFERS(span.data() + 3), subspan.data());
EXPECT_EQ(0u, subspan.size());
static_assert(0u == decltype(subspan)::extent, "");
}
{
auto subspan = span.last<1>();
// `array` has three elmenents, so `span` has three elements, so
// `span.data() + 2` points within it.
EXPECT_EQ(UNSAFE_BUFFERS(span.data() + 2), subspan.data());
EXPECT_EQ(1u, subspan.size());
static_assert(1u == decltype(subspan)::extent, "");
EXPECT_EQ(3, subspan[0]);
}
{
auto subspan = span.last<2>();
// `array` has three elmenents, so `span` has three elements, so
// `span.data() + 1` points within it.
EXPECT_EQ(UNSAFE_BUFFERS(span.data() + 1), subspan.data());
EXPECT_EQ(2u, subspan.size());
static_assert(2u == decltype(subspan)::extent, "");
EXPECT_EQ(2, subspan[0]);
EXPECT_EQ(3, subspan[1]);
}
{
auto subspan = span.last<3>();
EXPECT_EQ(span.data(), subspan.data());
EXPECT_EQ(3u, subspan.size());
static_assert(3u == decltype(subspan)::extent, "");
EXPECT_EQ(1, subspan[0]);
EXPECT_EQ(2, subspan[1]);
EXPECT_EQ(3, subspan[2]);
}
}
TEST(SpanTest, TemplatedSubspanFromDynamicSpan) {
int array[] = {1, 2, 3};
span<int, 3> span(array);
{
auto subspan = span.subspan<0>();
EXPECT_EQ(span.data(), subspan.data());
static_assert(3u == decltype(subspan)::extent, "");
EXPECT_EQ(3u, subspan.size());
EXPECT_EQ(1, subspan[0]);
EXPECT_EQ(2, subspan[1]);
EXPECT_EQ(3, subspan[2]);
}
{
auto subspan = span.subspan<1>();
// SAFETY: `array` has three elmenents, so `span` has three elements, so
// `span.data() + 1` points within it.
EXPECT_EQ(UNSAFE_BUFFERS(span.data() + 1), subspan.data());
EXPECT_EQ(2u, subspan.size());
static_assert(2u == decltype(subspan)::extent, "");
EXPECT_EQ(2, subspan[0]);
EXPECT_EQ(3, subspan[1]);
}
{
auto subspan = span.subspan<2>();
// SAFETY: `array` has three elmenents, so `span` has three elements, so
// `span.data() + 2` points within it.
EXPECT_EQ(UNSAFE_BUFFERS(span.data() + 2), subspan.data());
EXPECT_EQ(1u, subspan.size());
static_assert(1u == decltype(subspan)::extent, "");
EXPECT_EQ(3, subspan[0]);
}
{
auto subspan = span.subspan<3>();
// SAFETY: `array` has three elmenents, so `span` has three elements, so
// `span.data() + 3` points to one byte beyond the object as permitted by
// C++ specification.
EXPECT_EQ(UNSAFE_BUFFERS(span.data() + 3), subspan.data());
EXPECT_EQ(0u, subspan.size());
static_assert(0u == decltype(subspan)::extent, "");
}
{
auto subspan = span.subspan<0, 0>();
EXPECT_EQ(span.data(), subspan.data());
EXPECT_EQ(0u, subspan.size());
static_assert(0u == decltype(subspan)::extent, "");
}
{
auto subspan = span.subspan<1, 0>();
// SAFETY: `array` has three elmenents, so `span` has three elements, so
// `span.data() + 1` points within it.
EXPECT_EQ(UNSAFE_BUFFERS(span.data() + 1), subspan.data());
EXPECT_EQ(0u, subspan.size());
static_assert(0u == decltype(subspan)::extent, "");
}
{
auto subspan = span.subspan<2, 0>();
// SAFETY: `array` has three elmenents, so `span` has three elements, so
// `span.data() + 2` points within it.
EXPECT_EQ(UNSAFE_BUFFERS(span.data() + 2), subspan.data());
EXPECT_EQ(0u, subspan.size());
static_assert(0u == decltype(subspan)::extent, "");
}
{
auto subspan = span.subspan<0, 1>();
EXPECT_EQ(span.data(), subspan.data());
EXPECT_EQ(1u, subspan.size());
static_assert(1u == decltype(subspan)::extent, "");
EXPECT_EQ(1, subspan[0]);
}
{
auto subspan = span.subspan<1, 1>();
// SAFETY: `array` has three elmenents, so `span` has three elements, so
// `span.data() + 1` points within it.
EXPECT_EQ(UNSAFE_BUFFERS(span.data() + 1), subspan.data());
EXPECT_EQ(1u, subspan.size());
static_assert(1u == decltype(subspan)::extent, "");
EXPECT_EQ(2, subspan[0]);
}
{
auto subspan = span.subspan<2, 1>();
// SAFETY: `array` has three elmenents, so `span` has three elements, so
// `span.data() + 2` points within it.
EXPECT_EQ(UNSAFE_BUFFERS(span.data() + 2), subspan.data());
EXPECT_EQ(1u, subspan.size());
static_assert(1u == decltype(subspan)::extent, "");
EXPECT_EQ(3, subspan[0]);
}
{
auto subspan = span.subspan<0, 2>();
EXPECT_EQ(span.data(), subspan.data());
EXPECT_EQ(2u, subspan.size());
static_assert(2u == decltype(subspan)::extent, "");
EXPECT_EQ(1, subspan[0]);
EXPECT_EQ(2, subspan[1]);
}
{
auto subspan = span.subspan<1, 2>();
// SAFETY: `array` has three elmenents, so `span` has three elements, so
// `span.data() + 1` points within it.
EXPECT_EQ(UNSAFE_BUFFERS(span.data() + 1), subspan.data());
EXPECT_EQ(2u, subspan.size());
static_assert(2u == decltype(subspan)::extent, "");
EXPECT_EQ(2, subspan[0]);
EXPECT_EQ(3, subspan[1]);
}
{
auto subspan = span.subspan<0, 3>();
EXPECT_EQ(span.data(), subspan.data());
EXPECT_EQ(3u, subspan.size());
static_assert(3u == decltype(subspan)::extent, "");
EXPECT_EQ(1, subspan[0]);
EXPECT_EQ(2, subspan[1]);
EXPECT_EQ(3, subspan[2]);
}
}
TEST(SpanTest, First) {
int array[] = {1, 2, 3};
span<int> span(array);
{
auto subspan = span.first(0u);
EXPECT_EQ(span.data(), subspan.data());
EXPECT_EQ(0u, subspan.size());
}
{
auto subspan = span.first(1u);
EXPECT_EQ(span.data(), subspan.data());
EXPECT_EQ(1u, subspan.size());
EXPECT_EQ(1, subspan[0]);
}
{
auto subspan = span.first(2u);
EXPECT_EQ(span.data(), subspan.data());
EXPECT_EQ(2u, subspan.size());
EXPECT_EQ(1, subspan[0]);
EXPECT_EQ(2, subspan[1]);
}
{
auto subspan = span.first(3u);
EXPECT_EQ(span.data(), subspan.data());
EXPECT_EQ(3u, subspan.size());
EXPECT_EQ(1, subspan[0]);
EXPECT_EQ(2, subspan[1]);
EXPECT_EQ(3, subspan[2]);
}
}
TEST(SpanTest, Last) {
int array[] = {1, 2, 3};
span<int> span(array);
{
auto subspan = span.last(0u);
// SAFETY: `array` has three elmenents, so `span` has three elements, so
// `span.data() + 3` points to one byte beyond the object, as permitted by
// C++ specification.
EXPECT_EQ(UNSAFE_BUFFERS(span.data() + 3), subspan.data());
EXPECT_EQ(0u, subspan.size());
}
{
auto subspan = span.last(1u);
// SAFETY: `array` has three elmenents, so `span` has three elements, so
// `span.data() + 2` points within it.
EXPECT_EQ(UNSAFE_BUFFERS(span.data() + 2), subspan.data());
EXPECT_EQ(1u, subspan.size());
EXPECT_EQ(3, subspan[0]);
}
{
auto subspan = span.last(2u);
// SAFETY: `array` has three elmenents, so `span` has three elements, so
// `span.data() + 1` points within it.
EXPECT_EQ(UNSAFE_BUFFERS(span.data() + 1), subspan.data());
EXPECT_EQ(2u, subspan.size());
EXPECT_EQ(2, subspan[0]);
EXPECT_EQ(3, subspan[1]);
}
{
auto subspan = span.last(3u);
EXPECT_EQ(span.data(), subspan.data());
EXPECT_EQ(3u, subspan.size());
EXPECT_EQ(1, subspan[0]);
EXPECT_EQ(2, subspan[1]);
EXPECT_EQ(3, subspan[2]);
}
}
TEST(SpanTest, Subspan) {
int array[] = {1, 2, 3};
span<int> span(array);
{
auto subspan = span.subspan(0);
EXPECT_EQ(span.data(), subspan.data());
EXPECT_EQ(3u, subspan.size());
EXPECT_EQ(1, subspan[0]);
EXPECT_EQ(2, subspan[1]);
EXPECT_EQ(3, subspan[2]);
}
{
auto subspan = span.subspan(1);
// SAFETY: `array` has three elmenents, so `span` has three elements, so
// `span.data() + 1` points within it.
EXPECT_EQ(UNSAFE_BUFFERS(span.data() + 1), subspan.data());
EXPECT_EQ(2u, subspan.size());
EXPECT_EQ(2, subspan[0]);
EXPECT_EQ(3, subspan[1]);
}
{
auto subspan = span.subspan(2);
// SAFETY: `array` has three elmenents, so `span` has three elements, so
// `span.data() + 2` points within it.
EXPECT_EQ(UNSAFE_BUFFERS(span.data() + 2), subspan.data());
EXPECT_EQ(1u, subspan.size());
EXPECT_EQ(3, subspan[0]);
}
{
auto subspan = span.subspan(3);
// SAFETY: `array` has three elmenents, so `span` has three elements, so
// `span.data() + 3` points to one byte beyond the object, as permitted by
// C++ specification.
EXPECT_EQ(UNSAFE_BUFFERS(span.data() + 3), subspan.data());
EXPECT_EQ(0u, subspan.size());
}
{
auto subspan = span.subspan(0, 0);
EXPECT_EQ(span.data(), subspan.data());
EXPECT_EQ(0u, subspan.size());
}
{
auto subspan = span.subspan(1, 0);
// SAFETY: `array` has three elmenents, so `span` has three elements, so
// `span.data() + 1` points within it.
EXPECT_EQ(UNSAFE_BUFFERS(span.data() + 1), subspan.data());
EXPECT_EQ(0u, subspan.size());
}
{
auto subspan = span.subspan(2, 0);
// SAFETY: `array` has three elmenents, so `span` has three elements, so
// `span.data() + 2` points within it.
EXPECT_EQ(UNSAFE_BUFFERS(span.data() + 2), subspan.data());
EXPECT_EQ(0u, subspan.size());
}
{
auto subspan = span.subspan(0, 1);
EXPECT_EQ(span.data(), subspan.data());
EXPECT_EQ(1u, subspan.size());
EXPECT_EQ(1, subspan[0]);
}
{
auto subspan = span.subspan(1, 1);
// SAFETY: `array` has three elmenents, so `span` has three elements, so
// `span.data() + 1` points within it.
EXPECT_EQ(UNSAFE_BUFFERS(span.data() + 1), subspan.data());
EXPECT_EQ(1u, subspan.size());
EXPECT_EQ(2, subspan[0]);
}
{
auto subspan = span.subspan(2, 1);
// SAFETY: `array` has three elmenents, so `span` has three elements, so
// `span.data() + 2` points within it.
EXPECT_EQ(UNSAFE_BUFFERS(span.data() + 2), subspan.data());
EXPECT_EQ(1u, subspan.size());
EXPECT_EQ(3, subspan[0]);
}
{
auto subspan = span.subspan(0, 2);
EXPECT_EQ(span.data(), subspan.data());
EXPECT_EQ(2u, subspan.size());
EXPECT_EQ(1, subspan[0]);
EXPECT_EQ(2, subspan[1]);
}
{
auto subspan = span.subspan(1, 2);
// SAFETY: `array` has three elmenents, so `span` has three elements, so
// `span.data() + 1` points within it.
EXPECT_EQ(UNSAFE_BUFFERS(span.data() + 1), subspan.data());
EXPECT_EQ(2u, subspan.size());
EXPECT_EQ(2, subspan[0]);
EXPECT_EQ(3, subspan[1]);
}
{
auto subspan = span.subspan(0, 3);
EXPECT_EQ(span.data(), subspan.data());
EXPECT_EQ(span.size(), subspan.size());
EXPECT_EQ(1, subspan[0]);
EXPECT_EQ(2, subspan[1]);
EXPECT_EQ(3, subspan[2]);
}
}
TEST(SpanTest, ToFixedExtent) {
{
const int kArray[] = {1, 2, 3};
const span<const int> s(kArray);
auto static_span = s.to_fixed_extent<3>();
ASSERT_TRUE(static_span.has_value());
static_assert(std::same_as<typename decltype(static_span)::value_type,
span<const int, 3>>);
EXPECT_EQ(s.data(), static_span->data());
EXPECT_EQ(s.size(), static_span->size());
EXPECT_EQ(std::nullopt, s.to_fixed_extent<4>());
}
}
TEST(SpanTest, Size) {
{
span<int> span;
EXPECT_EQ(0u, span.size());
}
{
int array[] = {1, 2, 3};
span<int> span(array);
EXPECT_EQ(3u, span.size());
}
}
TEST(SpanTest, SizeBytes) {
{
span<int> span;
EXPECT_EQ(0u, span.size_bytes());
}
{
int array[] = {1, 2, 3};
span<int> span(array);
EXPECT_EQ(3u * sizeof(int), span.size_bytes());
}
}
TEST(SpanTest, Empty) {
{
span<int> span;
EXPECT_TRUE(span.empty());
}
{
int array[] = {1, 2, 3};
span<int> span(array);
EXPECT_FALSE(span.empty());
}
{
std::vector<int> vector = {1, 2, 3};
span<int> s = vector;
// SAFETY: The empty range at end of a vector is a valid range.
span<int> span_of_checked_iterators = UNSAFE_BUFFERS({s.end(), s.end()});
EXPECT_TRUE(span_of_checked_iterators.empty());
}
}
TEST(SpanTest, OperatorAt) {
static constexpr int kArray[] = {1, 6, 1, 8, 0};
constexpr span<const int> span(kArray);
static_assert(&kArray[0] == &span[0],
"span[0] does not refer to the same element as kArray[0]");
static_assert(&kArray[1] == &span[1],
"span[1] does not refer to the same element as kArray[1]");
static_assert(&kArray[2] == &span[2],
"span[2] does not refer to the same element as kArray[2]");
static_assert(&kArray[3] == &span[3],
"span[3] does not refer to the same element as kArray[3]");
static_assert(&kArray[4] == &span[4],
"span[4] does not refer to the same element as kArray[4]");
}
TEST(SpanTest, Front) {
static constexpr int kArray[] = {1, 6, 1, 8, 0};
constexpr span<const int> span(kArray);
static_assert(&kArray[0] == &span.front(),
"span.front() does not refer to the same element as kArray[0]");
}
TEST(SpanTest, Back) {
static constexpr int kArray[] = {1, 6, 1, 8, 0};
constexpr span<const int> span(kArray);
static_assert(&kArray[4] == &span.back(),
"span.back() does not refer to the same element as kArray[4]");
}
TEST(SpanTest, Iterator) {
static constexpr int kArray[] = {1, 6, 1, 8, 0};
constexpr span<const int> span(kArray);
std::vector<int> results;
for (int i : span) {
results.emplace_back(i);
}
EXPECT_THAT(results, ElementsAre(1, 6, 1, 8, 0));
}
TEST(SpanTest, ConstexprIterator) {
static constexpr int kArray[] = {1, 6, 1, 8, 0};
constexpr span<const int> span(kArray);
static_assert(ranges::equal(kArray, span), "");
static_assert(1 == span.begin()[0], "");
static_assert(1 == *(span.begin() += 0), "");
static_assert(6 == *(span.begin() += 1), "");
static_assert(1 == *((span.begin() + 1) -= 1), "");
static_assert(6 == *((span.begin() + 1) -= 0), "");
static_assert(0 + span.begin() == span.begin() + 0);
static_assert(1 + span.begin() == span.begin() + 1);
}
TEST(SpanTest, ReverseIterator) {
static constexpr int kArray[] = {1, 6, 1, 8, 0};
constexpr span<const int> span(kArray);
EXPECT_TRUE(ranges::equal(Reversed(kArray), Reversed(span)));
}
TEST(SpanTest, AsBytes) {
{
constexpr int kArray[] = {2, 3, 5, 7, 11, 13};
auto bytes_span = as_bytes(make_span(kArray));
static_assert(std::is_same_v<decltype(bytes_span),
base::span<const uint8_t, sizeof(kArray)>>);
EXPECT_EQ(reinterpret_cast<const uint8_t*>(kArray), bytes_span.data());
EXPECT_EQ(sizeof(kArray), bytes_span.size());
EXPECT_EQ(bytes_span.size(), bytes_span.size_bytes());
}
{
std::vector<int> vec = {1, 1, 2, 3, 5, 8};
span<int> mutable_span(vec);
auto bytes_span = as_bytes(mutable_span);
static_assert(
std::is_same_v<decltype(bytes_span), base::span<const uint8_t>>);
EXPECT_EQ(reinterpret_cast<const uint8_t*>(vec.data()), bytes_span.data());
EXPECT_EQ(sizeof(int) * vec.size(), bytes_span.size());
EXPECT_EQ(bytes_span.size(), bytes_span.size_bytes());
}
}
TEST(SpanTest, AsWritableBytes) {
{
std::vector<int> vec = {1, 1, 2, 3, 5, 8};
span<int> mutable_span(vec);
auto writable_bytes_span = as_writable_bytes(mutable_span);
static_assert(
std::is_same_v<decltype(writable_bytes_span), base::span<uint8_t>>);
EXPECT_EQ(reinterpret_cast<uint8_t*>(vec.data()),
writable_bytes_span.data());
EXPECT_EQ(sizeof(int) * vec.size(), writable_bytes_span.size());
EXPECT_EQ(writable_bytes_span.size(), writable_bytes_span.size_bytes());
// Set the first entry of vec by writing through the span.
std::ranges::fill(writable_bytes_span.first(sizeof(int)), 'a');
static_assert(sizeof(int) == 4u); // Otherwise char literal wrong below.
EXPECT_EQ('aaaa', vec[0]);
}
{
std::vector<int> vec = {1, 1, 2, 3, 5, 8};
raw_span<int> mutable_raw_span(vec);
auto writable_bytes_span = as_writable_bytes(mutable_raw_span);
static_assert(
std::is_same_v<decltype(writable_bytes_span), base::span<uint8_t>>);
EXPECT_EQ(reinterpret_cast<uint8_t*>(vec.data()),
writable_bytes_span.data());
EXPECT_EQ(sizeof(int) * vec.size(), writable_bytes_span.size());
EXPECT_EQ(writable_bytes_span.size(), writable_bytes_span.size_bytes());
// Set the first entry of vec by writing through the span.
std::ranges::fill(writable_bytes_span.first(sizeof(int)), 'a');
static_assert(sizeof(int) == 4u); // Otherwise char literal wrong below.
EXPECT_EQ('aaaa', vec[0]);
}
}
TEST(SpanTest, AsChars) {
{
constexpr int kArray[] = {2, 3, 5, 7, 11, 13};
auto chars_span = as_chars(make_span(kArray));
static_assert(std::is_same_v<decltype(chars_span),
base::span<const char, sizeof(kArray)>>);
EXPECT_EQ(reinterpret_cast<const char*>(kArray), chars_span.data());
EXPECT_EQ(sizeof(kArray), chars_span.size());
EXPECT_EQ(chars_span.size(), chars_span.size_bytes());
}
{
std::vector<int> vec = {1, 1, 2, 3, 5, 8};
span<int> mutable_span(vec);
auto chars_span = as_chars(mutable_span);
static_assert(std::is_same_v<decltype(chars_span), base::span<const char>>);
EXPECT_EQ(reinterpret_cast<const char*>(vec.data()), chars_span.data());
EXPECT_EQ(sizeof(int) * vec.size(), chars_span.size());
EXPECT_EQ(chars_span.size(), chars_span.size_bytes());
}
{
std::vector<int> vec = {1, 1, 2, 3, 5, 8};
raw_span<int> mutable_span(vec);
auto chars_span = as_chars(mutable_span);
static_assert(std::is_same_v<decltype(chars_span), base::span<const char>>);
EXPECT_EQ(reinterpret_cast<const char*>(vec.data()), chars_span.data());
EXPECT_EQ(sizeof(int) * vec.size(), chars_span.size());
EXPECT_EQ(chars_span.size(), chars_span.size_bytes());
}
}
TEST(SpanTest, AsWritableChars) {
{
std::vector<int> vec = {1, 1, 2, 3, 5, 8};
span<int> mutable_span(vec);
auto writable_chars_span = as_writable_chars(mutable_span);
static_assert(
std::is_same_v<decltype(writable_chars_span), base::span<char>>);
EXPECT_EQ(reinterpret_cast<char*>(vec.data()), writable_chars_span.data());
EXPECT_EQ(sizeof(int) * vec.size(), writable_chars_span.size());
EXPECT_EQ(writable_chars_span.size(), writable_chars_span.size_bytes());
// Set the first entry of vec by writing through the span.
std::ranges::fill(writable_chars_span.first(sizeof(int)), 'a');
static_assert(sizeof(int) == 4u); // Otherwise char literal wrong below.
EXPECT_EQ('aaaa', vec[0]);
}
{
std::vector<int> vec = {1, 1, 2, 3, 5, 8};
raw_span<int> mutable_span(vec);
auto writable_chars_span = as_writable_chars(mutable_span);
static_assert(
std::is_same_v<decltype(writable_chars_span), base::span<char>>);
EXPECT_EQ(reinterpret_cast<char*>(vec.data()), writable_chars_span.data());
EXPECT_EQ(sizeof(int) * vec.size(), writable_chars_span.size());
EXPECT_EQ(writable_chars_span.size(), writable_chars_span.size_bytes());
// Set the first entry of vec by writing through the span.
std::ranges::fill(writable_chars_span.first(sizeof(int)), 'a');
static_assert(sizeof(int) == 4u); // Otherwise char literal wrong below.
EXPECT_EQ('aaaa', vec[0]);
}
}
TEST(SpanTest, AsByteSpan) {
{
constexpr int kArray[] = {2, 3, 5, 7, 11, 13};
auto byte_span = as_byte_span(kArray);
static_assert(std::is_same_v<decltype(byte_span),
span<const uint8_t, 6u * sizeof(int)>>);
EXPECT_EQ(byte_span.data(), reinterpret_cast<const uint8_t*>(kArray));
EXPECT_EQ(byte_span.size(), sizeof(kArray));
}
{
const std::vector<int> kVec({2, 3, 5, 7, 11, 13});
auto byte_span = as_byte_span(kVec);
static_assert(std::is_same_v<decltype(byte_span), span<const uint8_t>>);
EXPECT_EQ(byte_span.data(), reinterpret_cast<const uint8_t*>(kVec.data()));
EXPECT_EQ(byte_span.size(), kVec.size() * sizeof(int));
}
{
int kMutArray[] = {2, 3, 5, 7};
auto byte_span = as_byte_span(kMutArray);
static_assert(std::is_same_v<decltype(byte_span),
span<const uint8_t, 4u * sizeof(int)>>);
EXPECT_EQ(byte_span.data(), reinterpret_cast<const uint8_t*>(kMutArray));
EXPECT_EQ(byte_span.size(), sizeof(kMutArray));
}
{
std::vector<int> kMutVec({2, 3, 5, 7});
auto byte_span = as_byte_span(kMutVec);
static_assert(std::is_same_v<decltype(byte_span), span<const uint8_t>>);
EXPECT_EQ(byte_span.data(),
reinterpret_cast<const uint8_t*>(kMutVec.data()));
EXPECT_EQ(byte_span.size(), kMutVec.size() * sizeof(int));
}
// Rvalue input.
{
[](auto byte_span) {
static_assert(std::is_same_v<decltype(byte_span),
span<const uint8_t, 6u * sizeof(int)>>);
EXPECT_EQ(byte_span.size(), 6u * sizeof(int));
// Little endian puts the low bits in the first byte.
EXPECT_EQ(byte_span[0u], 2);
}(as_byte_span({2, 3, 5, 7, 11, 13}));
}
}
TEST(SpanTest, AsWritableByteSpan) {
{
int kMutArray[] = {2, 3, 5, 7};
auto byte_span = as_writable_byte_span(kMutArray);
static_assert(
std::is_same_v<decltype(byte_span), span<uint8_t, 4u * sizeof(int)>>);
EXPECT_EQ(byte_span.data(), reinterpret_cast<uint8_t*>(kMutArray));
EXPECT_EQ(byte_span.size(), sizeof(kMutArray));
}
{
std::vector<int> kMutVec({2, 3, 5, 7});
auto byte_span = as_writable_byte_span(kMutVec);
static_assert(std::is_same_v<decltype(byte_span), span<uint8_t>>);
EXPECT_EQ(byte_span.data(), reinterpret_cast<uint8_t*>(kMutVec.data()));
EXPECT_EQ(byte_span.size(), kMutVec.size() * sizeof(int));
}
// Rvalue input.
{
[](auto byte_span) {
static_assert(
std::is_same_v<decltype(byte_span), span<uint8_t, 6u * sizeof(int)>>);
EXPECT_EQ(byte_span.size(), 6u * sizeof(int));
// Little endian puts the low bits in the first byte.
EXPECT_EQ(byte_span[0u], 2);
}(as_writable_byte_span({2, 3, 5, 7, 11, 13}));
}
}
TEST(SpanTest, AsStringView) {
{
constexpr uint8_t kArray[] = {'h', 'e', 'l', 'l', 'o'};
// Fixed size span.
auto s = as_string_view(kArray);
static_assert(std::is_same_v<decltype(s), std::string_view>);
EXPECT_EQ(s.data(), reinterpret_cast<const char*>(&kArray[0u]));
EXPECT_EQ(s.size(), std::size(kArray));
// Dynamic size span.
auto s2 = as_string_view(base::span<const uint8_t>(kArray));
static_assert(std::is_same_v<decltype(s2), std::string_view>);
EXPECT_EQ(s2.data(), reinterpret_cast<const char*>(&kArray[0u]));
EXPECT_EQ(s2.size(), std::size(kArray));
}
{
constexpr char kArray[] = {'h', 'e', 'l', 'l', 'o'};
// Fixed size span.
auto s = as_string_view(kArray);
static_assert(std::is_same_v<decltype(s), std::string_view>);
EXPECT_EQ(s.data(), &kArray[0u]);
EXPECT_EQ(s.size(), std::size(kArray));
// Dynamic size span.
auto s2 = as_string_view(base::span<const char>(kArray));
static_assert(std::is_same_v<decltype(s2), std::string_view>);
EXPECT_EQ(s2.data(), &kArray[0u]);
EXPECT_EQ(s2.size(), std::size(kArray));
}
}
TEST(SpanTest, MakeSpanFromDataAndSize) {
int* nullint = nullptr;
// SAFETY: zero size is correct when pointer is NULL.
auto empty_span = UNSAFE_BUFFERS(make_span(nullint, 0u));
EXPECT_TRUE(empty_span.empty());
EXPECT_EQ(nullptr, empty_span.data());
std::vector<int> vector = {1, 1, 2, 3, 5, 8};
// SAFETY: vector.size() describes valid portion of vector.data().
span<int> UNSAFE_BUFFERS(expected_span(vector.data(), vector.size()));
auto made_span = UNSAFE_BUFFERS(make_span(vector.data(), vector.size()));
EXPECT_EQ(expected_span.data(), made_span.data());
EXPECT_EQ(expected_span.size(), made_span.size());
static_assert(decltype(made_span)::extent == dynamic_extent, "");
static_assert(std::is_same_v<decltype(expected_span), decltype(made_span)>,
"the type of made_span differs from expected_span!");
}
TEST(SpanTest, MakeSpanFromPointerPair) {
int* nullint = nullptr;
// SAFETY: The empty range between NULL and NULL is valid range.
auto empty_span = UNSAFE_BUFFERS(make_span(nullint, nullint));
EXPECT_TRUE(empty_span.empty());
EXPECT_EQ(nullptr, empty_span.data());
std::vector<int> vector = {1, 1, 2, 3, 5, 8};
// SAFETY: `vector.size()` describes valid portion of `vector.data()`.
span<int> UNSAFE_BUFFERS(expected_span(vector.data(), vector.size()));
auto made_span =
UNSAFE_BUFFERS(make_span(vector.data(), vector.data() + vector.size()));
EXPECT_EQ(expected_span.data(), made_span.data());
EXPECT_EQ(expected_span.size(), made_span.size());
static_assert(decltype(made_span)::extent == dynamic_extent, "");
static_assert(std::is_same_v<decltype(expected_span), decltype(made_span)>,
"the type of made_span differs from expected_span!");
}
TEST(SpanTest, MakeSpanFromConstexprArray) {
static constexpr int kArray[] = {1, 2, 3, 4, 5};
constexpr span<const int, 5> expected_span(kArray);
constexpr auto made_span = make_span(kArray);
EXPECT_EQ(expected_span.data(), made_span.data());
EXPECT_EQ(expected_span.size(), made_span.size());
static_assert(decltype(made_span)::extent == 5, "");
static_assert(std::is_same_v<decltype(expected_span), decltype(made_span)>,
"the type of made_span differs from expected_span!");
}
TEST(SpanTest, MakeSpanFromStdArray) {
const std::array<int, 5> kArray = {{1, 2, 3, 4, 5}};
span<const int, 5> expected_span(kArray);
auto made_span = make_span(kArray);
EXPECT_EQ(expected_span.data(), made_span.data());
EXPECT_EQ(expected_span.size(), made_span.size());
static_assert(decltype(made_span)::extent == 5, "");
static_assert(std::is_same_v<decltype(expected_span), decltype(made_span)>,
"the type of made_span differs from expected_span!");
}
TEST(SpanTest, MakeSpanFromConstContainer) {
const std::vector<int> vector = {-1, -2, -3, -4, -5};
span<const int> expected_span(vector);
auto made_span = make_span(vector);
EXPECT_EQ(expected_span.data(), made_span.data());
EXPECT_EQ(expected_span.size(), made_span.size());
static_assert(decltype(made_span)::extent == dynamic_extent, "");
static_assert(std::is_same_v<decltype(expected_span), decltype(made_span)>,
"the type of made_span differs from expected_span!");
}
TEST(SpanTest, MakeSpanFromContainer) {
std::vector<int> vector = {-1, -2, -3, -4, -5};
span<int> expected_span(vector);
auto made_span = make_span(vector);
EXPECT_EQ(expected_span.data(), made_span.data());
EXPECT_EQ(expected_span.size(), made_span.size());
static_assert(decltype(made_span)::extent == dynamic_extent, "");
static_assert(std::is_same_v<decltype(expected_span), decltype(made_span)>,
"the type of made_span differs from expected_span!");
}
TEST(SpanTest, MakeSpanFromRValueContainer) {
std::vector<int> vector = {-1, -2, -3, -4, -5};
span<const int> expected_span(vector);
// Note: While static_cast<T&&>(foo) is effectively just a fancy spelling of
// std::move(foo), make_span does not actually take ownership of the passed in
// container. Writing it this way makes it more obvious that we simply care
// about the right behavour when passing rvalues.
auto made_span = make_span(static_cast<std::vector<int>&&>(vector));
EXPECT_EQ(expected_span.data(), made_span.data());
EXPECT_EQ(expected_span.size(), made_span.size());
static_assert(decltype(made_span)::extent == dynamic_extent, "");
static_assert(std::is_same_v<decltype(expected_span), decltype(made_span)>,
"the type of made_span differs from expected_span!");
}
TEST(SpanTest, MakeSpanFromDynamicSpan) {
static constexpr int kArray[] = {1, 2, 3, 4, 5};
constexpr span<const int> expected_span(kArray);
constexpr auto made_span = make_span(expected_span);
static_assert(std::is_same_v<decltype(expected_span)::element_type,
decltype(made_span)::element_type>,
"make_span(span) should have the same element_type as span");
static_assert(expected_span.data() == made_span.data(),
"make_span(span) should have the same data() as span");
static_assert(expected_span.size() == made_span.size(),
"make_span(span) should have the same size() as span");
static_assert(decltype(made_span)::extent == decltype(expected_span)::extent,
"make_span(span) should have the same extent as span");
static_assert(std::is_same_v<decltype(expected_span), decltype(made_span)>,
"the type of made_span differs from expected_span!");
}
TEST(SpanTest, MakeSpanFromStaticSpan) {
static constexpr int kArray[] = {1, 2, 3, 4, 5};
constexpr span<const int, 5> expected_span(kArray);
constexpr auto made_span = make_span(expected_span);
static_assert(std::is_same_v<decltype(expected_span)::element_type,
decltype(made_span)::element_type>,
"make_span(span) should have the same element_type as span");
static_assert(expected_span.data() == made_span.data(),
"make_span(span) should have the same data() as span");
static_assert(expected_span.size() == made_span.size(),
"make_span(span) should have the same size() as span");
static_assert(decltype(made_span)::extent == decltype(expected_span)::extent,
"make_span(span) should have the same extent as span");
static_assert(std::is_same_v<decltype(expected_span), decltype(made_span)>,
"the type of made_span differs from expected_span!");
}
TEST(SpanTest, EnsureConstexprGoodness) {
static constexpr std::array<int, 5> kArray = {5, 4, 3, 2, 1};
constexpr span<const int> constexpr_span(kArray);
const size_t size = 2;
const size_t start = 1;
constexpr span<const int> subspan =
constexpr_span.subspan(start, start + size);
for (size_t i = 0; i < subspan.size(); ++i) {
EXPECT_EQ(kArray[start + i], subspan[i]);
}
constexpr span<const int> firsts = constexpr_span.first(size);
for (size_t i = 0; i < firsts.size(); ++i) {
EXPECT_EQ(kArray[i], firsts[i]);
}
constexpr span<const int> lasts = constexpr_span.last(size);
for (size_t i = 0; i < lasts.size(); ++i) {
const size_t j = (std::size(kArray) - size) + i;
EXPECT_EQ(kArray[j], lasts[i]);
}
constexpr int item = constexpr_span[size];
EXPECT_EQ(kArray[size], item);
}
TEST(SpanTest, OutOfBoundsDeath) {
constexpr span<int, 0> kEmptySpan;
ASSERT_DEATH_IF_SUPPORTED(kEmptySpan[0], "");
ASSERT_DEATH_IF_SUPPORTED(kEmptySpan.first(1u), "");
ASSERT_DEATH_IF_SUPPORTED(kEmptySpan.last(1u), "");
ASSERT_DEATH_IF_SUPPORTED(kEmptySpan.subspan(1u), "");
constexpr span<int> kEmptyDynamicSpan;
ASSERT_DEATH_IF_SUPPORTED(kEmptyDynamicSpan[0], "");
ASSERT_DEATH_IF_SUPPORTED(kEmptyDynamicSpan.front(), "");
ASSERT_DEATH_IF_SUPPORTED(kEmptyDynamicSpan.first(1u), "");
ASSERT_DEATH_IF_SUPPORTED(kEmptyDynamicSpan.last(1u), "");
ASSERT_DEATH_IF_SUPPORTED(kEmptyDynamicSpan.back(), "");
ASSERT_DEATH_IF_SUPPORTED(kEmptyDynamicSpan.subspan(1), "");
static constexpr int kArray[] = {0, 1, 2};
constexpr span<const int> kNonEmptyDynamicSpan(kArray);
EXPECT_EQ(3U, kNonEmptyDynamicSpan.size());
ASSERT_DEATH_IF_SUPPORTED(kNonEmptyDynamicSpan[4], "");
ASSERT_DEATH_IF_SUPPORTED(kNonEmptyDynamicSpan.subspan(10), "");
ASSERT_DEATH_IF_SUPPORTED(kNonEmptyDynamicSpan.subspan(1, 7), "");
size_t minus_one = static_cast<size_t>(-1);
ASSERT_DEATH_IF_SUPPORTED(kNonEmptyDynamicSpan.subspan(minus_one), "");
ASSERT_DEATH_IF_SUPPORTED(kNonEmptyDynamicSpan.subspan(minus_one, minus_one),
"");
ASSERT_DEATH_IF_SUPPORTED(kNonEmptyDynamicSpan.subspan(minus_one, 1), "");
// Span's iterators should be checked. To confirm the crashes come from the
// iterator checks and not stray memory accesses, we create spans that are
// backed by larger arrays.
int array1[] = {1, 2, 3, 4};
int array2[] = {1, 2, 3, 4};
span<int> span_len2 = span(array1).first(2u);
span<int> span_len3 = span(array2).first(3u);
ASSERT_DEATH_IF_SUPPORTED(*span_len2.end(), "");
ASSERT_DEATH_IF_SUPPORTED(span_len2.begin()[2], "");
ASSERT_DEATH_IF_SUPPORTED(span_len2.begin() + 3, "");
ASSERT_DEATH_IF_SUPPORTED(span_len2.begin() - 1, "");
ASSERT_DEATH_IF_SUPPORTED(span_len2.end() + 1, "");
// When STL functions take explicit end iterators, bounds checking happens
// at the caller, when end iterator is created. However, some APIs take only a
// begin iterator and determine end implicitly. In that case, bounds checking
// happens inside the STL. However, the STL sometimes specializes operations
// on contiguous iterators. These death ensures this specialization does not
// lose hardening.
//
// Note that these tests are necessary, but not sufficient, to demonstrate
// that iterators are suitably checked. The output iterator is currently
// checked too late due to https://crbug.com/1520041.
// Copying more values than fit in the destination.
ASSERT_DEATH_IF_SUPPORTED(
std::copy(span_len3.begin(), span_len3.end(), span_len2.begin()), "");
ASSERT_DEATH_IF_SUPPORTED(std::ranges::copy(span_len3, span_len2.begin()),
"");
ASSERT_DEATH_IF_SUPPORTED(
std::copy_n(span_len3.begin(), 3, span_len2.begin()), "");
// Copying more values than exist in the source.
ASSERT_DEATH_IF_SUPPORTED(
std::copy_n(span_len2.begin(), 3, span_len3.begin()), "");
}
TEST(SpanTest, IteratorIsRangeMoveSafe) {
static constexpr int kArray[] = {1, 6, 1, 8, 0};
const size_t kNumElements = 5;
constexpr span<const int> span(kArray);
static constexpr int kOverlappingStartIndexes[] = {-4, 0, 3, 4};
static constexpr int kNonOverlappingStartIndexes[] = {-7, -5, 5, 7};
// Overlapping ranges.
for (const int dest_start_index : kOverlappingStartIndexes) {
EXPECT_FALSE(CheckedContiguousIterator<const int>::IsRangeMoveSafe(
span.begin(), span.end(),
// SAFETY: TODO(tsepez): iterator constructor safety is dubious
// given that we are adding indices like -4 to `data()`.
UNSAFE_BUFFERS(CheckedContiguousIterator<const int>(
span.data() + dest_start_index,
span.data() + dest_start_index + kNumElements))));
}
// Non-overlapping ranges.
for (const int dest_start_index : kNonOverlappingStartIndexes) {
EXPECT_TRUE(CheckedContiguousIterator<const int>::IsRangeMoveSafe(
span.begin(), span.end(),
// SAFETY: TODO(tsepez): iterator constructor safety is dubious
// given that we are adding indices like -7 to `data()`.
UNSAFE_BUFFERS(CheckedContiguousIterator<const int>(
span.data() + dest_start_index,
span.data() + dest_start_index + kNumElements))));
}
// IsRangeMoveSafe is true if the length to be moved is 0.
EXPECT_TRUE(CheckedContiguousIterator<const int>::IsRangeMoveSafe(
span.begin(), span.begin(),
// SAFETY: Empty range at the start of a span is always valid.
UNSAFE_BUFFERS(
CheckedContiguousIterator<const int>(span.data(), span.data()))));
// IsRangeMoveSafe is false if end < begin.
EXPECT_FALSE(CheckedContiguousIterator<const int>::IsRangeMoveSafe(
span.end(), span.begin(),
// SAFETY: Empty range at the start of a span is always valid.
UNSAFE_BUFFERS(
CheckedContiguousIterator<const int>(span.data(), span.data()))));
}
TEST(SpanTest, Sort) {
int array[] = {5, 4, 3, 2, 1};
span<int> dynamic_span = array;
ranges::sort(dynamic_span);
EXPECT_THAT(array, ElementsAre(1, 2, 3, 4, 5));
std::sort(dynamic_span.rbegin(), dynamic_span.rend());
EXPECT_THAT(array, ElementsAre(5, 4, 3, 2, 1));
span<int, 5> static_span = array;
std::sort(static_span.rbegin(), static_span.rend(), std::greater<>());
EXPECT_THAT(array, ElementsAre(1, 2, 3, 4, 5));
ranges::sort(static_span, std::greater<>());
EXPECT_THAT(array, ElementsAre(5, 4, 3, 2, 1));
}
TEST(SpanTest, SpanExtentConversions) {
// Statically checks that various conversions between spans of dynamic and
// static extent are possible or not.
static_assert(std::is_constructible_v<span<int, 0>, span<int>>,
"Error: static span should be constructible from dynamic span");
static_assert(
!std::is_convertible_v<span<int>, span<int, 0>>,
"Error: static span should not be convertible from dynamic span");
static_assert(!std::is_constructible_v<span<int, 2>, span<int, 1>>,
"Error: static span should not be constructible from static "
"span with different extent");
static_assert(std::is_convertible_v<span<int, 0>, span<int>>,
"Error: static span should be convertible to dynamic span");
static_assert(std::is_convertible_v<span<int>, span<int>>,
"Error: dynamic span should be convertible to dynamic span");
static_assert(std::is_convertible_v<span<int, 2>, span<int, 2>>,
"Error: static span should be convertible to static span");
}
TEST(SpanTest, IteratorConversions) {
static_assert(
std::is_convertible_v<span<int>::iterator, span<const int>::iterator>,
"Error: iterator should be convertible to const iterator");
static_assert(
!std::is_convertible_v<span<const int>::iterator, span<int>::iterator>,
"Error: const iterator should not be convertible to iterator");
}
TEST(SpanTest, ExtentMacro) {
constexpr size_t kSize = 10;
std::array<uint8_t, kSize> array;
static_assert(EXTENT(array) == kSize, "EXTENT broken");
const std::array<uint8_t, kSize>& reference = array;
static_assert(EXTENT(reference) == kSize, "EXTENT broken for references");
const std::array<uint8_t, kSize>* pointer = nullptr;
static_assert(EXTENT(*pointer) == kSize, "EXTENT broken for pointers");
uint8_t plain_array[kSize] = {0};
static_assert(EXTENT(plain_array) == kSize, "EXTENT broken for plain arrays");
}
TEST(SpanTest, CopyFrom) {
int arr[] = {1, 2, 3};
span<int, 0> empty_static_span;
span<int, 3> static_span = base::make_span(arr);
std::vector<int> vec = {4, 5, 6};
span<int> empty_dynamic_span;
span<int> dynamic_span = base::make_span(vec);
// Handle empty cases gracefully.
// Dynamic size to static size requires an explicit conversion.
empty_static_span.copy_from(*empty_dynamic_span.to_fixed_extent<0>());
empty_dynamic_span.copy_from(empty_static_span);
static_span.first(empty_static_span.size()).copy_from(empty_static_span);
dynamic_span.first(empty_dynamic_span.size()).copy_from(empty_dynamic_span);
EXPECT_THAT(arr, ElementsAre(1, 2, 3));
EXPECT_THAT(vec, ElementsAre(4, 5, 6));
// Test too small destinations.
EXPECT_DEATH_IF_SUPPORTED(empty_static_span.copy_from(dynamic_span), "");
EXPECT_DEATH_IF_SUPPORTED(empty_dynamic_span.copy_from(static_span), "");
EXPECT_DEATH_IF_SUPPORTED(empty_dynamic_span.copy_from(dynamic_span), "");
EXPECT_DEATH_IF_SUPPORTED(dynamic_span.last(2u).copy_from(static_span), "");
std::vector<int> source = {7, 8, 9};
static_span.first(2u).copy_from(span(source).last(2u));
EXPECT_THAT(arr, ElementsAre(8, 9, 3));
dynamic_span.first(2u).copy_from(span(source).last(2u));
EXPECT_THAT(vec, ElementsAre(8, 9, 6));
static_span.first(1u).copy_from(span(source).last(1u));
EXPECT_THAT(arr, ElementsAre(9, 9, 3));
dynamic_span.first(1u).copy_from(span(source).last(1u));
EXPECT_THAT(vec, ElementsAre(9, 9, 6));
struct NonTrivial {
NonTrivial(int o) : i(o) {}
NonTrivial(const NonTrivial& o) : i(o) {}
NonTrivial& operator=(const NonTrivial& o) {
i = o;
return *this;
}
operator int() const { return i; }
int i;
};
// Overlapping spans. Fixed size.
{
int long_arr_is_long[] = {1, 2, 3, 4, 5, 6, 7};
auto left = span(long_arr_is_long).first<5>();
auto right = span(long_arr_is_long).last<5>();
left.copy_from(right);
EXPECT_THAT(long_arr_is_long, ElementsAre(3, 4, 5, 6, 7, 6, 7));
}
{
int long_arr_is_long[] = {1, 2, 3, 4, 5, 6, 7};
auto left = span(long_arr_is_long).first<5>();
auto right = span(long_arr_is_long).last<5>();
right.copy_from(left);
EXPECT_THAT(long_arr_is_long, ElementsAre(1, 2, 1, 2, 3, 4, 5));
}
{
int long_arr_is_long[] = {1, 2, 3, 4, 5, 6, 7};
auto left = span(long_arr_is_long).first<5>();
left.copy_from(left);
EXPECT_THAT(long_arr_is_long, ElementsAre(1, 2, 3, 4, 5, 6, 7));
}
{
NonTrivial long_arr_is_long[] = {1, 2, 3, 4, 5, 6, 7};
auto left = span(long_arr_is_long).first<5>();
auto right = span(long_arr_is_long).last<5>();
left.copy_from(right);
EXPECT_THAT(long_arr_is_long, ElementsAre(3, 4, 5, 6, 7, 6, 7));
}
{
NonTrivial long_arr_is_long[] = {1, 2, 3, 4, 5, 6, 7};
auto left = span(long_arr_is_long).first<5>();
auto right = span(long_arr_is_long).last<5>();
right.copy_from(left);
EXPECT_THAT(long_arr_is_long, ElementsAre(1, 2, 1, 2, 3, 4, 5));
}
{
NonTrivial long_arr_is_long[] = {1, 2, 3, 4, 5, 6, 7};
auto left = span(long_arr_is_long).first<5>();
left.copy_from(left);
EXPECT_THAT(long_arr_is_long, ElementsAre(1, 2, 3, 4, 5, 6, 7));
}
// Overlapping spans. Dynamic size.
{
int long_arr_is_long[] = {1, 2, 3, 4, 5, 6, 7};
auto left = span<int>(long_arr_is_long).first(5u);
auto right = span<int>(long_arr_is_long).last(5u);
left.copy_from(right);
EXPECT_THAT(long_arr_is_long, ElementsAre(3, 4, 5, 6, 7, 6, 7));
}
{
int long_arr_is_long[] = {1, 2, 3, 4, 5, 6, 7};
auto left = span<int>(long_arr_is_long).first(5u);
auto right = span<int>(long_arr_is_long).last(5u);
right.copy_from(left);
EXPECT_THAT(long_arr_is_long, ElementsAre(1, 2, 1, 2, 3, 4, 5));
}
{
int long_arr_is_long[] = {1, 2, 3, 4, 5, 6, 7};
auto left = span<int>(long_arr_is_long).first(5u);
left.copy_from(left);
EXPECT_THAT(long_arr_is_long, ElementsAre(1, 2, 3, 4, 5, 6, 7));
}
{
NonTrivial long_arr_is_long[] = {1, 2, 3, 4, 5, 6, 7};
auto left = span<NonTrivial>(long_arr_is_long).first(5u);
auto right = span<NonTrivial>(long_arr_is_long).last(5u);
left.copy_from(right);
EXPECT_THAT(long_arr_is_long, ElementsAre(3, 4, 5, 6, 7, 6, 7));
}
{
NonTrivial long_arr_is_long[] = {1, 2, 3, 4, 5, 6, 7};
auto left = span<NonTrivial>(long_arr_is_long).first(5u);
auto right = span<NonTrivial>(long_arr_is_long).last(5u);
right.copy_from(left);
EXPECT_THAT(long_arr_is_long, ElementsAre(1, 2, 1, 2, 3, 4, 5));
}
{
NonTrivial long_arr_is_long[] = {1, 2, 3, 4, 5, 6, 7};
auto left = span<NonTrivial>(long_arr_is_long).first(5u);
left.copy_from(left);
EXPECT_THAT(long_arr_is_long, ElementsAre(1, 2, 3, 4, 5, 6, 7));
}
}
TEST(SpanTest, CopyFromNonoverlapping) {
int arr[] = {1, 2, 3};
span<int, 0> empty_static_span;
span<int, 3> static_span = base::make_span(arr);
std::vector<int> vec = {4, 5, 6};
span<int> empty_dynamic_span;
span<int> dynamic_span = base::make_span(vec);
// Handle empty cases gracefully.
UNSAFE_BUFFERS({
empty_static_span.copy_from_nonoverlapping(empty_dynamic_span);
empty_dynamic_span.copy_from_nonoverlapping(empty_static_span);
static_span.first(empty_static_span.size())
.copy_from_nonoverlapping(empty_static_span);
dynamic_span.first(empty_dynamic_span.size())
.copy_from_nonoverlapping(empty_dynamic_span);
EXPECT_THAT(arr, ElementsAre(1, 2, 3));
EXPECT_THAT(vec, ElementsAre(4, 5, 6));
// Test too small destinations.
EXPECT_DEATH_IF_SUPPORTED(
empty_static_span.copy_from_nonoverlapping(dynamic_span), "");
EXPECT_DEATH_IF_SUPPORTED(
empty_dynamic_span.copy_from_nonoverlapping(static_span), "");
EXPECT_DEATH_IF_SUPPORTED(
empty_dynamic_span.copy_from_nonoverlapping(dynamic_span), "");
EXPECT_DEATH_IF_SUPPORTED(
dynamic_span.last(2u).copy_from_nonoverlapping(static_span), "");
std::vector<int> source = {7, 8, 9};
static_span.first(2u).copy_from_nonoverlapping(span(source).last(2u));
EXPECT_THAT(arr, ElementsAre(8, 9, 3));
dynamic_span.first(2u).copy_from_nonoverlapping(span(source).last(2u));
EXPECT_THAT(vec, ElementsAre(8, 9, 6));
static_span.first(1u).copy_from_nonoverlapping(span(source).last(1u));
EXPECT_THAT(arr, ElementsAre(9, 9, 3));
dynamic_span.first(1u).copy_from_nonoverlapping(span(source).last(1u));
EXPECT_THAT(vec, ElementsAre(9, 9, 6));
})
}
TEST(SpanTest, CopyFromConversion) {
int arr[] = {1, 2, 3};
span<int, 3> static_span = base::make_span(arr);
std::vector<int> vec = {4, 5, 6};
span<int> dynamic_span = base::make_span(vec);
std::vector convert_from = {7, 8, 9};
static_span.copy_from(convert_from);
dynamic_span.copy_from(convert_from);
EXPECT_THAT(static_span, ElementsAre(7, 8, 9));
EXPECT_THAT(dynamic_span, ElementsAre(7, 8, 9));
std::array<int, 3u> convert_from_fixed = {4, 5, 6};
static_span.copy_from(convert_from_fixed);
dynamic_span.copy_from(convert_from_fixed);
EXPECT_THAT(static_span, ElementsAre(4, 5, 6));
EXPECT_THAT(dynamic_span, ElementsAre(4, 5, 6));
int convert_from_array[] = {1, 2, 3};
static_span.copy_from(convert_from_array);
dynamic_span.copy_from(convert_from_array);
EXPECT_THAT(static_span, ElementsAre(1, 2, 3));
EXPECT_THAT(dynamic_span, ElementsAre(1, 2, 3));
int convert_from_const_array[] = {-1, -2, -3};
static_span.copy_from(convert_from_const_array);
dynamic_span.copy_from(convert_from_const_array);
EXPECT_THAT(static_span, ElementsAre(-1, -2, -3));
EXPECT_THAT(dynamic_span, ElementsAre(-1, -2, -3));
}
TEST(SpanTest, CopyPrefixFrom) {
const int vals[] = {1, 2, 3, 4, 5};
int arr[] = {1, 2, 3, 4, 5};
span<int, 2> fixed2 = span(arr).first<2>();
span<int, 3> fixed3 = span(arr).last<3>();
span<int> dyn2 = span(arr).first(2u);
span<int> dyn3 = span(arr).last(3u);
// Copy from a larger buffer.
EXPECT_CHECK_DEATH(fixed2.copy_prefix_from(dyn3));
EXPECT_CHECK_DEATH(dyn2.copy_prefix_from(fixed3));
EXPECT_CHECK_DEATH(dyn2.copy_prefix_from(dyn3));
// Copy from a smaller buffer into the prefix.
fixed3.copy_prefix_from(fixed2);
EXPECT_THAT(arr, ElementsAre(1, 2, 1, 2, 5));
span(arr).copy_from(vals);
fixed3.copy_prefix_from(dyn2);
EXPECT_THAT(arr, ElementsAre(1, 2, 1, 2, 5));
span(arr).copy_from(vals);
dyn3.copy_prefix_from(fixed2);
EXPECT_THAT(arr, ElementsAre(1, 2, 1, 2, 5));
span(arr).copy_from(vals);
dyn3.copy_prefix_from(dyn2);
EXPECT_THAT(arr, ElementsAre(1, 2, 1, 2, 5));
span(arr).copy_from(vals);
// Copy from an empty buffer.
fixed2.copy_prefix_from(span<int, 0>());
EXPECT_THAT(arr, ElementsAre(1, 2, 3, 4, 5));
fixed2.copy_prefix_from(span<int>());
EXPECT_THAT(arr, ElementsAre(1, 2, 3, 4, 5));
dyn2.copy_prefix_from(span<int, 0>());
EXPECT_THAT(arr, ElementsAre(1, 2, 3, 4, 5));
dyn2.copy_prefix_from(span<int>());
EXPECT_THAT(arr, ElementsAre(1, 2, 3, 4, 5));
// Copy from a same-size buffer.
fixed3.first<2>().copy_prefix_from(fixed2);
EXPECT_THAT(arr, ElementsAre(1, 2, 1, 2, 5));
span(arr).copy_from(vals);
fixed3.first<2>().copy_prefix_from(dyn2);
EXPECT_THAT(arr, ElementsAre(1, 2, 1, 2, 5));
span(arr).copy_from(vals);
dyn3.first(2u).copy_prefix_from(fixed2);
EXPECT_THAT(arr, ElementsAre(1, 2, 1, 2, 5));
span(arr).copy_from(vals);
dyn3.first(2u).copy_prefix_from(dyn2);
EXPECT_THAT(arr, ElementsAre(1, 2, 1, 2, 5));
span(arr).copy_from(vals);
}
TEST(SpanTest, SplitAt) {
int arr[] = {1, 2, 3};
span<int, 0> empty_static_span;
span<int, 3> static_span = base::make_span(arr);
std::vector<int> vec = {4, 5, 6};
span<int> empty_dynamic_span;
span<int> dynamic_span = base::make_span(vec);
{
auto [left, right] = empty_static_span.split_at(0u);
EXPECT_EQ(left.size(), 0u);
EXPECT_EQ(right.size(), 0u);
}
{
auto [left, right] = empty_dynamic_span.split_at(0u);
EXPECT_EQ(left.size(), 0u);
EXPECT_EQ(right.size(), 0u);
}
{
auto [left, right] = static_span.split_at(0u);
EXPECT_EQ(left.size(), 0u);
EXPECT_EQ(right.size(), 3u);
EXPECT_EQ(right.front(), 1);
}
{
auto [left, right] = static_span.split_at(3u);
EXPECT_EQ(left.size(), 3u);
EXPECT_EQ(right.size(), 0u);
EXPECT_EQ(left.front(), 1);
}
{
auto [left, right] = static_span.split_at(1u);
EXPECT_EQ(left.size(), 1u);
EXPECT_EQ(right.size(), 2u);
EXPECT_EQ(left.front(), 1);
EXPECT_EQ(right.front(), 2);
}
{
auto [left, right] = dynamic_span.split_at(0u);
EXPECT_EQ(left.size(), 0u);
EXPECT_EQ(right.size(), 3u);
EXPECT_EQ(right.front(), 4);
}
{
auto [left, right] = dynamic_span.split_at(3u);
EXPECT_EQ(left.size(), 3u);
EXPECT_EQ(right.size(), 0u);
EXPECT_EQ(left.front(), 4);
}
{
auto [left, right] = dynamic_span.split_at(1u);
EXPECT_EQ(left.size(), 1u);
EXPECT_EQ(right.size(), 2u);
EXPECT_EQ(left.front(), 4);
EXPECT_EQ(right.front(), 5);
}
// Fixed-size splits.
{
auto [left, right] = static_span.split_at<0u>();
static_assert(std::same_as<decltype(left), span<int, 0u>>);
static_assert(std::same_as<decltype(right), span<int, 3u>>);
EXPECT_EQ(left.data(), static_span.data());
EXPECT_EQ(right.data(), static_span.data());
}
{
auto [left, right] = static_span.split_at<1u>();
static_assert(std::same_as<decltype(left), span<int, 1u>>);
static_assert(std::same_as<decltype(right), span<int, 2u>>);
EXPECT_EQ(left.data(), static_span.data());
// SAFETY: `array` has three elmenents, so `static_span` has three
// elements, so `static_span.data() + 1u` points within it.
EXPECT_EQ(right.data(), UNSAFE_BUFFERS(static_span.data() + 1u));
}
{
auto [left, right] = static_span.split_at<3u>();
static_assert(std::same_as<decltype(left), span<int, 3u>>);
static_assert(std::same_as<decltype(right), span<int, 0u>>);
EXPECT_EQ(left.data(), static_span.data());
// SAFETY: `array` has three elmenents, so `static_span` has three
// elements, so `static_span.data() + 3u` points to one byte beyond
// the end of the object as permitted by C++ standard.
EXPECT_EQ(right.data(), UNSAFE_BUFFERS(static_span.data() + 3u));
}
{
auto [left, right] = dynamic_span.split_at<0u>();
static_assert(std::same_as<decltype(left), span<int, 0u>>);
static_assert(std::same_as<decltype(right), span<int>>);
EXPECT_EQ(left.data(), dynamic_span.data());
EXPECT_EQ(right.data(), dynamic_span.data());
EXPECT_EQ(right.size(), 3u);
}
{
auto [left, right] = dynamic_span.split_at<1u>();
static_assert(std::same_as<decltype(left), span<int, 1u>>);
static_assert(std::same_as<decltype(right), span<int>>);
EXPECT_EQ(left.data(), dynamic_span.data());
// SAFETY: `array` has three elmenents, so `dynamic_span` has three
// elements, so `dynamic_span.data() + 1u` points within it.
EXPECT_EQ(right.data(), UNSAFE_BUFFERS(dynamic_span.data() + 1u));
EXPECT_EQ(right.size(), 2u);
}
{
auto [left, right] = dynamic_span.split_at<3u>();
static_assert(std::same_as<decltype(left), span<int, 3u>>);
static_assert(std::same_as<decltype(right), span<int>>);
EXPECT_EQ(left.data(), dynamic_span.data());
// SAFETY: `array` has three elmenents, so `dynamic_span` has three
// elements, so `dynamic_span.data() + 3u` points to one byte beyond
// the end of the object as permitted by C++ standard.
EXPECT_EQ(right.data(), UNSAFE_BUFFERS(dynamic_span.data() + 3u));
EXPECT_EQ(right.size(), 0u);
}
// Invalid fixed-size split from dynamic will fail at runtime.
EXPECT_CHECK_DEATH({ dynamic_span.split_at<4u>(); });
}
TEST(SpanTest, CompareEquality) {
static_assert(std::equality_comparable<int>);
int32_t arr2[] = {1, 2};
int32_t arr3[] = {1, 2, 3};
int32_t rra3[] = {3, 2, 1};
int32_t vec3[] = {1, 2, 3};
constexpr const int32_t arr2_c[] = {1, 2};
constexpr const int32_t arr3_c[] = {1, 2, 3};
constexpr const int32_t rra3_c[] = {3, 2, 1};
// Comparing empty spans that are fixed and dynamic size.
EXPECT_TRUE((span<int32_t>() == span<int32_t>()));
EXPECT_TRUE((span<int32_t, 0u>() == span<int32_t>()));
EXPECT_TRUE((span<int32_t>() == span<int32_t, 0u>()));
EXPECT_TRUE((span<int32_t, 0u>() == span<int32_t, 0u>()));
// Non-null data pointer, but both are empty.
EXPECT_TRUE(span(arr2).first(0u) == span(arr2).last(0u));
EXPECT_TRUE(span(arr2).first<0u>() == span(arr2).last<0u>());
// Spans of different dynamic sizes.
EXPECT_TRUE(span(arr2).first(2u) != span(arr3).first(3u));
// Spans of same dynamic size and same values.
EXPECT_TRUE(span(arr2).first(2u) == span(arr3).first(2u));
// Spans of same dynamic size but different values.
EXPECT_TRUE(span(arr2).first(2u) != span(rra3).first(2u));
// Spans of different sizes (one dynamic one fixed).
EXPECT_TRUE(span(arr2).first<2u>() != span(arr3).first(3u));
EXPECT_TRUE(span(arr2).first(2u) != span(arr3).first<3u>());
// Spans of same size and same values.
EXPECT_TRUE(span(arr2).first<2u>() == span(arr3).first(2u));
EXPECT_TRUE(span(arr2).first(2u) == span(arr3).first<2u>());
// Spans of same size but different values.
EXPECT_TRUE(span(arr2).first<2u>() != span(rra3).first(2u));
EXPECT_TRUE(span(arr2).first(2u) != span(rra3).first<2u>());
// Spans of different fixed sizes do not compile (as in Rust)
// https://godbolt.org/z/MrnbPeozr and are covered in nocompile tests.
// Comparing const and non-const. Same tests as above otherwise.
EXPECT_TRUE((span<const int32_t>() == span<int32_t>()));
EXPECT_TRUE((span<const int32_t, 0u>() == span<int32_t>()));
EXPECT_TRUE((span<const int32_t>() == span<int32_t, 0u>()));
EXPECT_TRUE((span<const int32_t, 0u>() == span<int32_t, 0u>()));
EXPECT_TRUE((span<int32_t>() == span<const int32_t>()));
EXPECT_TRUE((span<int32_t, 0u>() == span<const int32_t>()));
EXPECT_TRUE((span<int32_t>() == span<const int32_t, 0u>()));
EXPECT_TRUE((span<int32_t, 0u>() == span<const int32_t, 0u>()));
EXPECT_TRUE(span(arr2_c).first(0u) == span(arr2).last(0u));
EXPECT_TRUE(span(arr2_c).first<0u>() == span(arr2).last<0u>());
EXPECT_TRUE(span(arr2).first(0u) == span(arr2_c).last(0u));
EXPECT_TRUE(span(arr2).first<0u>() == span(arr2_c).last<0u>());
EXPECT_TRUE(span(arr2_c).first(2u) != span(arr3).first(3u));
EXPECT_TRUE(span(arr2_c).first(2u) == span(arr3).first(2u));
EXPECT_TRUE(span(arr2_c).first(2u) != span(rra3).first(2u));
EXPECT_TRUE(span(arr2).first(2u) != span(arr3_c).first(3u));
EXPECT_TRUE(span(arr2).first(2u) == span(arr3_c).first(2u));
EXPECT_TRUE(span(arr2).first(2u) != span(rra3_c).first(2u));
EXPECT_TRUE(span(arr2_c).first<2u>() != span(arr3).first(3u));
EXPECT_TRUE(span(arr2_c).first(2u) != span(arr3).first<3u>());
EXPECT_TRUE(span(arr2_c).first<2u>() == span(arr3).first(2u));
EXPECT_TRUE(span(arr2_c).first(2u) == span(arr3).first<2u>());
EXPECT_TRUE(span(arr2_c).first<2u>() != span(rra3).first(2u));
EXPECT_TRUE(span(arr2_c).first(2u) != span(rra3).first<2u>());
EXPECT_TRUE(span(arr2).first<2u>() != span(arr3_c).first(3u));
EXPECT_TRUE(span(arr2).first(2u) != span(arr3_c).first<3u>());
EXPECT_TRUE(span(arr2).first<2u>() == span(arr3_c).first(2u));
EXPECT_TRUE(span(arr2).first(2u) == span(arr3_c).first<2u>());
EXPECT_TRUE(span(arr2).first<2u>() != span(rra3_c).first(2u));
EXPECT_TRUE(span(arr2).first(2u) != span(rra3_c).first<2u>());
// Comparing different types which are comparable. Same tests as above
// otherwise.
static_assert(std::equality_comparable_with<int32_t, int64_t>);
int64_t arr2_l[] = {1, 2};
int64_t arr3_l[] = {1, 2, 3};
int64_t rra3_l[] = {3, 2, 1};
EXPECT_TRUE((span<int32_t>() == span<int64_t>()));
EXPECT_TRUE((span<int32_t, 0u>() == span<int64_t>()));
EXPECT_TRUE((span<int32_t>() == span<int64_t, 0u>()));
EXPECT_TRUE((span<int32_t, 0u>() == span<int64_t, 0u>()));
EXPECT_TRUE((span<int32_t>() == span<int64_t>()));
EXPECT_TRUE((span<int32_t, 0u>() == span<int64_t>()));
EXPECT_TRUE((span<int32_t>() == span<int64_t, 0u>()));
EXPECT_TRUE((span<int32_t, 0u>() == span<int64_t, 0u>()));
EXPECT_TRUE(span(arr2_l).first(0u) == span(arr2).last(0u));
EXPECT_TRUE(span(arr2_l).first<0u>() == span(arr2).last<0u>());
EXPECT_TRUE(span(arr2).first(0u) == span(arr2_l).last(0u));
EXPECT_TRUE(span(arr2).first<0u>() == span(arr2_l).last<0u>());
EXPECT_TRUE(span(arr2_l).first(2u) != span(arr3).first(3u));
EXPECT_TRUE(span(arr2_l).first(2u) == span(arr3).first(2u));
EXPECT_TRUE(span(arr2_l).first(2u) != span(rra3).first(2u));
EXPECT_TRUE(span(arr2).first(2u) != span(arr3_l).first(3u));
EXPECT_TRUE(span(arr2).first(2u) == span(arr3_l).first(2u));
EXPECT_TRUE(span(arr2).first(2u) != span(rra3_l).first(2u));
EXPECT_TRUE(span(arr2_l).first<2u>() != span(arr3).first(3u));
EXPECT_TRUE(span(arr2_l).first(2u) != span(arr3).first<3u>());
EXPECT_TRUE(span(arr2_l).first<2u>() == span(arr3).first(2u));
EXPECT_TRUE(span(arr2_l).first(2u) == span(arr3).first<2u>());
EXPECT_TRUE(span(arr2_l).first<2u>() != span(rra3).first(2u));
EXPECT_TRUE(span(arr2_l).first(2u) != span(rra3).first<2u>());
EXPECT_TRUE(span(arr2).first<2u>() != span(arr3_l).first(3u));
EXPECT_TRUE(span(arr2).first(2u) != span(arr3_l).first<3u>());
EXPECT_TRUE(span(arr2).first<2u>() == span(arr3_l).first(2u));
EXPECT_TRUE(span(arr2).first(2u) == span(arr3_l).first<2u>());
EXPECT_TRUE(span(arr2).first<2u>() != span(rra3_l).first(2u));
EXPECT_TRUE(span(arr2).first(2u) != span(rra3_l).first<2u>());
// Comparing different types and different const-ness at the same time.
constexpr const int64_t arr2_lc[] = {1, 2};
constexpr const int64_t arr3_lc[] = {1, 2, 3};
constexpr const int64_t rra3_lc[] = {3, 2, 1};
EXPECT_TRUE((span<const int32_t>() == span<int64_t>()));
EXPECT_TRUE((span<const int32_t, 0u>() == span<int64_t>()));
EXPECT_TRUE((span<const int32_t>() == span<int64_t, 0u>()));
EXPECT_TRUE((span<const int32_t, 0u>() == span<int64_t, 0u>()));
EXPECT_TRUE((span<int32_t>() == span<const int64_t>()));
EXPECT_TRUE((span<int32_t, 0u>() == span<const int64_t>()));
EXPECT_TRUE((span<int32_t>() == span<const int64_t, 0u>()));
EXPECT_TRUE((span<int32_t, 0u>() == span<const int64_t, 0u>()));
EXPECT_TRUE(span(arr2_lc).first(0u) == span(arr2).last(0u));
EXPECT_TRUE(span(arr2_lc).first<0u>() == span(arr2).last<0u>());
EXPECT_TRUE(span(arr2).first(0u) == span(arr2_lc).last(0u));
EXPECT_TRUE(span(arr2).first<0u>() == span(arr2_lc).last<0u>());
EXPECT_TRUE(span(arr2_lc).first(2u) != span(arr3).first(3u));
EXPECT_TRUE(span(arr2_lc).first(2u) == span(arr3).first(2u));
EXPECT_TRUE(span(arr2_lc).first(2u) != span(rra3).first(2u));
EXPECT_TRUE(span(arr2).first(2u) != span(arr3_lc).first(3u));
EXPECT_TRUE(span(arr2).first(2u) == span(arr3_lc).first(2u));
EXPECT_TRUE(span(arr2).first(2u) != span(rra3_lc).first(2u));
EXPECT_TRUE(span(arr2_lc).first<2u>() != span(arr3).first(3u));
EXPECT_TRUE(span(arr2_lc).first(2u) != span(arr3).first<3u>());
EXPECT_TRUE(span(arr2_lc).first<2u>() == span(arr3).first(2u));
EXPECT_TRUE(span(arr2_lc).first(2u) == span(arr3).first<2u>());
EXPECT_TRUE(span(arr2_lc).first<2u>() != span(rra3).first(2u));
EXPECT_TRUE(span(arr2_lc).first(2u) != span(rra3).first<2u>());
EXPECT_TRUE(span(arr2).first<2u>() != span(arr3_lc).first(3u));
EXPECT_TRUE(span(arr2).first(2u) != span(arr3_lc).first<3u>());
EXPECT_TRUE(span(arr2).first<2u>() == span(arr3_lc).first(2u));
EXPECT_TRUE(span(arr2).first(2u) == span(arr3_lc).first<2u>());
EXPECT_TRUE(span(arr2).first<2u>() != span(rra3_lc).first(2u));
EXPECT_TRUE(span(arr2).first(2u) != span(rra3_lc).first<2u>());
// Comparing with an implicit conversion to span. This only works if the span
// types actually match (i.e. not for any comparable types) since otherwise
// the type can not be deduced. Implicit conversion from mutable to const
// can be inferred though.
EXPECT_TRUE(arr2 != span(arr3).first(3u));
EXPECT_TRUE(arr2 == span(arr3).first(2u));
EXPECT_TRUE(arr2 != span(rra3).first(2u));
EXPECT_TRUE(arr2 != span(arr3_c).first(3u));
EXPECT_TRUE(arr2 == span(arr3_c).first(2u));
EXPECT_TRUE(arr2 != span(rra3_c).first(2u));
EXPECT_TRUE(arr2_c != span(arr3).first(3u));
EXPECT_TRUE(arr2_c == span(arr3).first(2u));
EXPECT_TRUE(arr2_c != span(rra3).first(2u));
// Comparing mutable to mutable, there's no ambiguity about which overload to
// call (mutable or implicit-const).
EXPECT_FALSE(span(arr3) == rra3); // Fixed size.
EXPECT_FALSE(span(vec3).first(2u) == vec3); // Dynamic size.
EXPECT_FALSE(span(arr3).first(2u) == rra3); // Fixed with dynamic size.
// Constexpr comparison.
static_assert(span<int>() == span<int, 0u>());
static_assert(span(arr2_c) == span(arr3_c).first(2u));
static_assert(span(arr2_c) == span(arr3_lc).first(2u));
}
TEST(SpanTest, CompareOrdered) {
static_assert(std::three_way_comparable<int>);
int32_t arr2[] = {1, 2};
int32_t arr3[] = {1, 2, 3};
int32_t rra3[] = {3, 2, 1};
int32_t vec3[] = {1, 2, 3};
constexpr const int32_t arr2_c[] = {1, 2};
constexpr const int32_t arr3_c[] = {1, 2, 3};
constexpr const int32_t rra3_c[] = {3, 2, 1};
// Less than.
EXPECT_TRUE(span(arr3) < span(rra3));
EXPECT_TRUE(span(arr2).first(2u) < span(arr3));
// Greater than.
EXPECT_TRUE(span(rra3) > span(arr3));
EXPECT_TRUE(span(arr3) > span(arr2).first(2u));
// Comparing empty spans that are fixed and dynamic size.
EXPECT_TRUE((span<int32_t>() <=> span<int32_t>()) == 0);
EXPECT_TRUE((span<int32_t, 0u>() <=> span<int32_t>()) == 0);
EXPECT_TRUE((span<int32_t>() <=> span<int32_t, 0u>()) == 0);
EXPECT_TRUE((span<int32_t, 0u>() <=> span<int32_t, 0u>()) == 0);
// Non-null data pointer, but both are empty.
EXPECT_TRUE(span(arr2).first(0u) <=> span(arr2).last(0u) == 0);
EXPECT_TRUE(span(arr2).first<0u>() <=> span(arr2).last<0u>() == 0);
// Spans of different dynamic sizes.
EXPECT_TRUE(span(arr2).first(2u) <=> span(arr3).first(3u) < 0);
// Spans of same dynamic size and same values.
EXPECT_TRUE(span(arr2).first(2u) <=> span(arr3).first(2u) == 0);
// Spans of same dynamic size but different values.
EXPECT_TRUE(span(arr2).first(2u) <=> span(rra3).first(2u) < 0);
// Spans of different sizes (one dynamic one fixed).
EXPECT_TRUE(span(arr2).first<2u>() <=> span(arr3).first(3u) < 0);
EXPECT_TRUE(span(arr2).first(2u) <=> span(arr3).first<3u>() < 0);
// Spans of same size and same values.
EXPECT_TRUE(span(arr2).first<2u>() <=> span(arr3).first(2u) == 0);
EXPECT_TRUE(span(arr2).first(2u) <=> span(arr3).first<2u>() == 0);
// Spans of same size but different values.
EXPECT_TRUE(span(arr2).first<2u>() <=> span(rra3).first(2u) < 0);
EXPECT_TRUE(span(arr2).first(2u) <=> span(rra3).first<2u>() < 0);
// Spans of different fixed sizes do not compile (as in Rust)
// https://godbolt.org/z/MrnbPeozr and are covered in nocompile tests.
// Comparing const and non-const. Same tests as above otherwise.
EXPECT_TRUE((span<const int32_t>() <=> span<int32_t>()) == 0);
EXPECT_TRUE((span<const int32_t, 0u>() <=> span<int32_t>()) == 0);
EXPECT_TRUE((span<const int32_t>() <=> span<int32_t, 0u>()) == 0);
EXPECT_TRUE((span<const int32_t, 0u>() <=> span<int32_t, 0u>()) == 0);
EXPECT_TRUE((span<int32_t>() <=> span<const int32_t>()) == 0);
EXPECT_TRUE((span<int32_t, 0u>() <=> span<const int32_t>()) == 0);
EXPECT_TRUE((span<int32_t>() <=> span<const int32_t, 0u>()) == 0);
EXPECT_TRUE((span<int32_t, 0u>() <=> span<const int32_t, 0u>()) == 0);
EXPECT_TRUE(span(arr2_c).first(0u) <=> span(arr2).last(0u) == 0);
EXPECT_TRUE(span(arr2_c).first<0u>() <=> span(arr2).last<0u>() == 0);
EXPECT_TRUE(span(arr2).first(0u) <=> span(arr2_c).last(0u) == 0);
EXPECT_TRUE(span(arr2).first<0u>() <=> span(arr2_c).last<0u>() == 0);
EXPECT_TRUE(span(arr2_c).first(2u) <=> span(arr3).first(3u) < 0);
EXPECT_TRUE(span(arr2_c).first(2u) <=> span(arr3).first(2u) == 0);
EXPECT_TRUE(span(arr2_c).first(2u) <=> span(rra3).first(2u) < 0);
EXPECT_TRUE(span(arr2).first(2u) <=> span(arr3_c).first(3u) < 0);
EXPECT_TRUE(span(arr2).first(2u) <=> span(arr3_c).first(2u) == 0);
EXPECT_TRUE(span(arr2).first(2u) <=> span(rra3_c).first(2u) < 0);
EXPECT_TRUE(span(arr2_c).first<2u>() <=> span(arr3).first(3u) < 0);
EXPECT_TRUE(span(arr2_c).first(2u) <=> span(arr3).first<3u>() < 0);
EXPECT_TRUE(span(arr2_c).first<2u>() <=> span(arr3).first(2u) == 0);
EXPECT_TRUE(span(arr2_c).first(2u) <=> span(arr3).first<2u>() == 0);
EXPECT_TRUE(span(arr2_c).first<2u>() <=> span(rra3).first(2u) < 0);
EXPECT_TRUE(span(arr2_c).first(2u) <=> span(rra3).first<2u>() < 0);
EXPECT_TRUE(span(arr2).first<2u>() <=> span(arr3_c).first(3u) < 0);
EXPECT_TRUE(span(arr2).first(2u) <=> span(arr3_c).first<3u>() < 0);
EXPECT_TRUE(span(arr2).first<2u>() <=> span(arr3_c).first(2u) == 0);
EXPECT_TRUE(span(arr2).first(2u) <=> span(arr3_c).first<2u>() == 0);
EXPECT_TRUE(span(arr2).first<2u>() <=> span(rra3_c).first(2u) < 0);
EXPECT_TRUE(span(arr2).first(2u) <=> span(rra3_c).first<2u>() < 0);
// Comparing different types which are comparable. Same tests as above
// otherwise.
static_assert(std::three_way_comparable_with<int32_t, int64_t>);
int64_t arr2_l[] = {1, 2};
int64_t arr3_l[] = {1, 2, 3};
int64_t rra3_l[] = {3, 2, 1};
EXPECT_TRUE((span<int32_t>() <=> span<int64_t>()) == 0);
EXPECT_TRUE((span<int32_t, 0u>() <=> span<int64_t>()) == 0);
EXPECT_TRUE((span<int32_t>() <=> span<int64_t, 0u>()) == 0);
EXPECT_TRUE((span<int32_t, 0u>() <=> span<int64_t, 0u>()) == 0);
EXPECT_TRUE((span<int32_t>() <=> span<int64_t>()) == 0);
EXPECT_TRUE((span<int32_t, 0u>() <=> span<int64_t>()) == 0);
EXPECT_TRUE((span<int32_t>() <=> span<int64_t, 0u>()) == 0);
EXPECT_TRUE((span<int32_t, 0u>() <=> span<int64_t, 0u>()) == 0);
EXPECT_TRUE(span(arr2_l).first(0u) <=> span(arr2).last(0u) == 0);
EXPECT_TRUE(span(arr2_l).first<0u>() <=> span(arr2).last<0u>() == 0);
EXPECT_TRUE(span(arr2).first(0u) <=> span(arr2_l).last(0u) == 0);
EXPECT_TRUE(span(arr2).first<0u>() <=> span(arr2_l).last<0u>() == 0);
EXPECT_TRUE(span(arr2_l).first(2u) <=> span(arr3).first(3u) < 0);
EXPECT_TRUE(span(arr2_l).first(2u) <=> span(arr3).first(2u) == 0);
EXPECT_TRUE(span(arr2_l).first(2u) <=> span(rra3).first(2u) < 0);
EXPECT_TRUE(span(arr2).first(2u) <=> span(arr3_l).first(3u) < 0);
EXPECT_TRUE(span(arr2).first(2u) <=> span(arr3_l).first(2u) == 0);
EXPECT_TRUE(span(arr2).first(2u) <=> span(rra3_l).first(2u) < 0);
EXPECT_TRUE(span(arr2_l).first<2u>() <=> span(arr3).first(3u) < 0);
EXPECT_TRUE(span(arr2_l).first(2u) <=> span(arr3).first<3u>() < 0);
EXPECT_TRUE(span(arr2_l).first<2u>() <=> span(arr3).first(2u) == 0);
EXPECT_TRUE(span(arr2_l).first(2u) <=> span(arr3).first<2u>() == 0);
EXPECT_TRUE(span(arr2_l).first<2u>() <=> span(rra3).first(2u) < 0);
EXPECT_TRUE(span(arr2_l).first(2u) <=> span(rra3).first<2u>() < 0);
EXPECT_TRUE(span(arr2).first<2u>() <=> span(arr3_l).first(3u) < 0);
EXPECT_TRUE(span(arr2).first(2u) <=> span(arr3_l).first<3u>() < 0);
EXPECT_TRUE(span(arr2).first<2u>() <=> span(arr3_l).first(2u) == 0);
EXPECT_TRUE(span(arr2).first(2u) <=> span(arr3_l).first<2u>() == 0);
EXPECT_TRUE(span(arr2).first<2u>() <=> span(rra3_l).first(2u) < 0);
EXPECT_TRUE(span(arr2).first(2u) <=> span(rra3_l).first<2u>() < 0);
// Comparing different types and different const-ness at the same time.
constexpr const int64_t arr2_lc[] = {1, 2};
constexpr const int64_t arr3_lc[] = {1, 2, 3};
constexpr const int64_t rra3_lc[] = {3, 2, 1};
EXPECT_TRUE((span<const int32_t>() <=> span<int64_t>()) == 0);
EXPECT_TRUE((span<const int32_t, 0u>() <=> span<int64_t>()) == 0);
EXPECT_TRUE((span<const int32_t>() <=> span<int64_t, 0u>()) == 0);
EXPECT_TRUE((span<const int32_t, 0u>() <=> span<int64_t, 0u>()) == 0);
EXPECT_TRUE((span<int32_t>() <=> span<const int64_t>()) == 0);
EXPECT_TRUE((span<int32_t, 0u>() <=> span<const int64_t>()) == 0);
EXPECT_TRUE((span<int32_t>() <=> span<const int64_t, 0u>()) == 0);
EXPECT_TRUE((span<int32_t, 0u>() <=> span<const int64_t, 0u>()) == 0);
EXPECT_TRUE(span(arr2_lc).first(0u) <=> span(arr2).last(0u) == 0);
EXPECT_TRUE(span(arr2_lc).first<0u>() <=> span(arr2).last<0u>() == 0);
EXPECT_TRUE(span(arr2).first(0u) <=> span(arr2_lc).last(0u) == 0);
EXPECT_TRUE(span(arr2).first<0u>() <=> span(arr2_lc).last<0u>() == 0);
EXPECT_TRUE(span(arr2_lc).first(2u) <=> span(arr3).first(3u) < 0);
EXPECT_TRUE(span(arr2_lc).first(2u) <=> span(arr3).first(2u) == 0);
EXPECT_TRUE(span(arr2_lc).first(2u) <=> span(rra3).first(2u) < 0);
EXPECT_TRUE(span(arr2).first(2u) <=> span(arr3_lc).first(3u) < 0);
EXPECT_TRUE(span(arr2).first(2u) <=> span(arr3_lc).first(2u) == 0);
EXPECT_TRUE(span(arr2).first(2u) <=> span(rra3_lc).first(2u) < 0);
EXPECT_TRUE(span(arr2_lc).first<2u>() <=> span(arr3).first(3u) < 0);
EXPECT_TRUE(span(arr2_lc).first(2u) <=> span(arr3).first<3u>() < 0);
EXPECT_TRUE(span(arr2_lc).first<2u>() <=> span(arr3).first(2u) == 0);
EXPECT_TRUE(span(arr2_lc).first(2u) <=> span(arr3).first<2u>() == 0);
EXPECT_TRUE(span(arr2_lc).first<2u>() <=> span(rra3).first(2u) < 0);
EXPECT_TRUE(span(arr2_lc).first(2u) <=> span(rra3).first<2u>() < 0);
EXPECT_TRUE(span(arr2).first<2u>() <=> span(arr3_lc).first(3u) < 0);
EXPECT_TRUE(span(arr2).first(2u) <=> span(arr3_lc).first<3u>() < 0);
EXPECT_TRUE(span(arr2).first<2u>() <=> span(arr3_lc).first(2u) == 0);
EXPECT_TRUE(span(arr2).first(2u) <=> span(arr3_lc).first<2u>() == 0);
EXPECT_TRUE(span(arr2).first<2u>() <=> span(rra3_lc).first(2u) < 0);
EXPECT_TRUE(span(arr2).first(2u) <=> span(rra3_lc).first<2u>() < 0);
// Comparing with an implicit conversion to span. This only works if the span
// types actually match (i.e. not for any comparable types) since otherwise
// the type can not be deduced. Implicit conversion from mutable to const
// can be inferred though.
EXPECT_TRUE(arr2 <=> span(arr3).first(3u) < 0);
EXPECT_TRUE(arr2 <=> span(arr3).first(2u) == 0);
EXPECT_TRUE(arr2 <=> span(rra3).first(2u) < 0);
EXPECT_TRUE(arr2 <=> span(arr3_c).first(3u) < 0);
EXPECT_TRUE(arr2 <=> span(arr3_c).first(2u) == 0);
EXPECT_TRUE(arr2 <=> span(rra3_c).first(2u) < 0);
EXPECT_TRUE(arr2_c <=> span(arr3).first(3u) < 0);
EXPECT_TRUE(arr2_c <=> span(arr3).first(2u) == 0);
EXPECT_TRUE(arr2_c <=> span(rra3).first(2u) < 0);
// Comparing mutable to mutable, there's no ambiguity about which overload to
// call (mutable or implicit-const).
EXPECT_FALSE(span(arr3) <=> rra3 == 0); // Fixed size.
EXPECT_FALSE(span(vec3).first(2u) <=> vec3 == 0); // Dynamic size.
EXPECT_FALSE(span(arr3).first(2u) <=> rra3 == 0); // Fixed with dynamic size.
// Constexpr comparison.
static_assert(span<int>() <=> span<int, 0u>() == 0);
static_assert(span(arr2_c) <=> span(arr3_c).first(2u) == 0);
static_assert(span(arr2_c) <=> span(arr3_lc).first(2u) == 0);
}
TEST(SpanTest, GMockMacroCompatibility) {
int arr1[] = {1, 3, 5};
int arr2[] = {1, 3, 5};
std::vector vec1(std::begin(arr1), std::end(arr1));
std::vector vec2(std::begin(arr2), std::end(arr2));
span<int, 3> static_span1(arr1);
span<int, 3> static_span2(arr2);
span<int> dynamic_span1(vec1);
span<int> dynamic_span2(vec2);
EXPECT_THAT(arr1, ElementsAreArray(static_span2));
EXPECT_THAT(arr1, ElementsAreArray(dynamic_span2));
EXPECT_THAT(vec1, ElementsAreArray(static_span2));
EXPECT_THAT(vec1, ElementsAreArray(dynamic_span2));
EXPECT_THAT(static_span1, ElementsAre(1, 3, 5));
EXPECT_THAT(static_span1, ElementsAreArray(arr2));
EXPECT_THAT(static_span1, ElementsAreArray(static_span2));
EXPECT_THAT(static_span1, ElementsAreArray(dynamic_span2));
EXPECT_THAT(static_span1, ElementsAreArray(vec2));
EXPECT_THAT(dynamic_span1, ElementsAre(1, 3, 5));
EXPECT_THAT(dynamic_span1, ElementsAreArray(arr2));
EXPECT_THAT(dynamic_span1, ElementsAreArray(static_span2));
EXPECT_THAT(dynamic_span1, ElementsAreArray(dynamic_span2));
EXPECT_THAT(dynamic_span1, ElementsAreArray(vec2));
}
TEST(SpanTest, GTestMacroCompatibility) {
int arr1[] = {1, 3, 5};
int arr2[] = {1, 3, 5};
int arr3[] = {2, 4, 6, 8};
std::vector vec1(std::begin(arr1), std::end(arr1));
std::vector vec2(std::begin(arr2), std::end(arr2));
std::vector vec3(std::begin(arr3), std::end(arr3));
span<int, 3> static_span1(arr1);
span<int, 3> static_span2(arr2);
span<int, 4> static_span3(arr3);
span<int> dynamic_span1(vec1);
span<int> dynamic_span2(vec2);
span<int> dynamic_span3(vec3);
// Alas, many desirable comparisions are still not possible. They
// are commented out below.
EXPECT_EQ(arr1, static_span2);
EXPECT_EQ(arr1, dynamic_span2);
// EXPECT_EQ(vec1, static_span2);
EXPECT_EQ(vec1, dynamic_span2);
EXPECT_EQ(static_span1, arr2);
EXPECT_EQ(static_span1, static_span2);
EXPECT_EQ(static_span1, dynamic_span2);
// EXPECT_EQ(static_span1, vec2);
EXPECT_EQ(dynamic_span1, arr2);
EXPECT_EQ(dynamic_span1, static_span2);
EXPECT_EQ(dynamic_span1, dynamic_span2);
EXPECT_EQ(dynamic_span1, vec2);
// EXPECT_NE(arr1, static_span3);
EXPECT_NE(arr1, dynamic_span3);
// EXPECT_NE(vec1, static_span3);
EXPECT_NE(vec1, dynamic_span3);
// EXPECT_NE(static_span1, arr3);
// EXPECT_NE(static_span1, static_span3);
EXPECT_NE(static_span1, dynamic_span3);
// EXPECT_NE(static_span1, vec3);
EXPECT_NE(dynamic_span1, arr3);
EXPECT_NE(dynamic_span1, static_span3);
EXPECT_NE(dynamic_span1, dynamic_span3);
EXPECT_NE(dynamic_span1, vec3);
}
// These are all examples from //docs/unsafe_buffers.md, copied here to ensure
// they compile.
TEST(SpanTest, Example_UnsafeBuffersPatterns) {
struct Object {
int a;
};
auto func_with_const_ptr_size = [](const uint8_t*, size_t) {};
auto func_with_mut_ptr_size = [](uint8_t*, size_t) {};
auto func_with_const_span = [](span<const uint8_t>) {};
auto func_with_mut_span = [](span<uint8_t>) {};
auto two_byte_arrays = [](const uint8_t*, const uint8_t*) {};
auto two_byte_spans = [](span<const uint8_t>, span<const uint8_t>) {};
UNSAFE_BUFFERS({
uint8_t array1[12];
uint8_t array2[16];
uint64_t array3[2];
memcpy(array1, array2 + 8, 4);
memcpy(array1 + 4, array3, 8);
})
{
uint8_t array1[12];
uint8_t array2[16];
uint64_t array3[2];
base::span(array1).first(4u).copy_from(base::span(array2).subspan(8u, 4u));
base::span(array1).subspan(4u).copy_from(
base::as_byte_span(array3).first(8u));
{
// Use `split_at()` to ensure `array1` is fully written.
auto [from2, from3] = base::span(array1).split_at(4u);
from2.copy_from(base::span(array2).subspan(8u, 4u));
from3.copy_from(base::as_byte_span(array3).first(8u));
}
{
// This can even be ensured at compile time (if sizes and offsets are all
// constants).
auto [from2, from3] = base::span(array1).split_at<4u>();
from2.copy_from(base::span(array2).subspan<8u, 4u>());
from3.copy_from(base::as_byte_span(array3).first<8u>());
}
}
UNSAFE_BUFFERS({
uint8_t array1[12];
uint64_t array2[2];
Object array3[4];
memset(array1, 0, 12);
memset(array2, 0, 2 * sizeof(uint64_t));
memset(array3, 0, 4 * sizeof(Object));
})
{
uint8_t array1[12];
uint64_t array2[2];
Object array3[4];
std::ranges::fill(array1, 0u);
std::ranges::fill(array2, 0u);
std::ranges::fill(base::as_writable_byte_span(array3), 0u);
}
UNSAFE_BUFFERS({
uint8_t array1[12] = {};
uint8_t array2[12] = {};
[[maybe_unused]] bool ne = memcmp(array1, array2, sizeof(array1)) == 0;
[[maybe_unused]] bool less = memcmp(array1, array2, sizeof(array1)) < 0;
// In tests.
for (size_t i = 0; i < sizeof(array1); ++i) {
SCOPED_TRACE(i);
EXPECT_EQ(array1[i], array2[i]);
}
})
{
uint8_t array1[12] = {};
uint8_t array2[12] = {};
// If one side is a span, the other will convert to span too.
[[maybe_unused]] bool eq = base::span(array1) == array2;
[[maybe_unused]] bool less = base::span(array1) < array2;
// In tests.
EXPECT_EQ(base::span(array1), array2);
}
UNSAFE_BUFFERS({
uint8_t array[44] = {};
uint32_t v1;
memcpy(&v1, array, sizeof(v1)); // Front.
uint64_t v2;
memcpy(&v2, array + 6, sizeof(v2)); // Middle.
})
{
uint8_t array[44] = {};
[[maybe_unused]] uint32_t v1 =
base::U32FromLittleEndian(base::span(array).first<4u>()); // Front.
[[maybe_unused]] uint64_t v2 = base::U64FromLittleEndian(
base::span(array).subspan<6u, 8u>()); // Middle.
}
UNSAFE_BUFFERS({
// `array` must be aligned for the cast to be valid. Moreover, the
// dereference is only valid because Chromium builds with
// -fno-strict-aliasing.
alignas(uint64_t) uint8_t array[44] = {};
[[maybe_unused]] uint32_t v1 =
*reinterpret_cast<const uint32_t*>(array); // Front.
[[maybe_unused]] uint64_t v2 =
*reinterpret_cast<const uint64_t*>(array + 16); // Middle.
})
{
uint8_t array[44] = {};
[[maybe_unused]] uint32_t v1 =
base::U32FromLittleEndian(base::span(array).first<4u>()); // Front.
[[maybe_unused]] uint64_t v2 = base::U64FromLittleEndian(
base::span(array).subspan<16u, 8u>()); // Middle.
}
UNSAFE_BUFFERS({
std::string str = "hello world";
func_with_const_ptr_size(reinterpret_cast<const uint8_t*>(str.data()),
str.size());
func_with_mut_ptr_size(reinterpret_cast<uint8_t*>(str.data()), str.size());
})
{
std::string str = "hello world";
base::span<const uint8_t> bytes = base::as_byte_span(str);
func_with_const_ptr_size(bytes.data(), bytes.size());
base::span<uint8_t> mut_bytes = base::as_writable_byte_span(str);
func_with_mut_ptr_size(mut_bytes.data(), mut_bytes.size());
// Replace pointer and size with a span, though.
func_with_const_span(base::as_byte_span(str));
func_with_mut_span(base::as_writable_byte_span(str));
}
UNSAFE_BUFFERS({
uint8_t array[8];
uint64_t val;
two_byte_arrays(array, reinterpret_cast<const uint8_t*>(&val));
})
{
uint8_t array[8];
uint64_t val;
base::span<uint8_t> val_span = base::byte_span_from_ref(val);
two_byte_arrays(array, val_span.data());
// Replace an unbounded pointer a span, though.
two_byte_spans(base::span(array), base::byte_span_from_ref(val));
}
}
TEST(SpanTest, Printing) {
struct S {
std::string ToString() const { return "S()"; }
};
// Gtest prints values in the spans. Chars are special.
EXPECT_EQ(testing::PrintToString(base::span({1, 2, 3})), "[1, 2, 3]");
EXPECT_EQ(testing::PrintToString(base::span({S(), S()})), "[S(), S()]");
EXPECT_EQ(testing::PrintToString(base::span({'a', 'b', 'c'})), "[\"abc\"]");
EXPECT_EQ(testing::PrintToString(base::span({'a', 'b', 'c', '\0'})),
std::string_view("[\"abc\0\"]", 8u));
EXPECT_EQ(testing::PrintToString(base::span({'a', 'b', '\0', 'c', '\0'})),
std::string_view("[\"ab\0c\0\"]", 9u));
EXPECT_EQ(testing::PrintToString(base::span<int>()), "[]");
EXPECT_EQ(testing::PrintToString(base::span<char>()), "[\"\"]");
// Base prints values in spans. Chars are special.
EXPECT_EQ(base::ToString(base::span({1, 2, 3})), "[1, 2, 3]");
EXPECT_EQ(base::ToString(base::span({S(), S()})), "[S(), S()]");
EXPECT_EQ(base::ToString(base::span({'a', 'b', 'c'})), "[\"abc\"]");
EXPECT_EQ(base::ToString(base::span({'a', 'b', 'c', '\0'})),
std::string_view("[\"abc\0\"]", 8u));
EXPECT_EQ(base::ToString(base::span({'a', 'b', '\0', 'c', '\0'})),
std::string_view("[\"ab\0c\0\"]", 9u));
EXPECT_EQ(base::ToString(base::span<int>()), "[]");
EXPECT_EQ(base::ToString(base::span<char>()), "[\"\"]");
}
} // namespace base
// Test for compatibility with std::span<>, in case some third-party
// API decides to use it. The size() and data() convention should mean
// that everyone's spans are compatible with each other.
TEST(SpanTest, FromStdSpan) {
int kData[] = {10, 11, 12};
std::span<const int> std_span(kData);
std::span<int> mut_std_span(kData);
std::span<const int, 3u> fixed_std_span(kData);
std::span<int, 3u> mut_fixed_std_span(kData);
// Tests *implicit* conversions through assignment construction.
{
base::span<const int> base_span = std_span;
EXPECT_EQ(base_span.size(), 3u);
EXPECT_EQ(base_span.data(), kData);
}
{
base::span<const int> base_span = mut_std_span;
EXPECT_EQ(base_span.size(), 3u);
EXPECT_EQ(base_span.data(), kData);
}
{
base::span<const int> base_span = fixed_std_span;
EXPECT_EQ(base_span.size(), 3u);
EXPECT_EQ(base_span.data(), kData);
}
{
base::span<const int> base_span = mut_fixed_std_span;
EXPECT_EQ(base_span.size(), 3u);
EXPECT_EQ(base_span.data(), kData);
}
{
base::span<const int, 3u> base_span = fixed_std_span;
EXPECT_EQ(base_span.size(), 3u);
EXPECT_EQ(base_span.data(), kData);
}
{
base::span<const int, 3u> base_span = mut_fixed_std_span;
EXPECT_EQ(base_span.size(), 3u);
EXPECT_EQ(base_span.data(), kData);
}
{
base::span<int, 3u> base_span = mut_fixed_std_span;
EXPECT_EQ(base_span.size(), 3u);
EXPECT_EQ(base_span.data(), kData);
}
{
auto base_made_span = base::make_span(std_span);
EXPECT_EQ(base_made_span.size(), 3u);
EXPECT_EQ(base_made_span.data(), kData);
}
{
auto base_byte_span = base::as_byte_span(std_span);
EXPECT_EQ(base_byte_span.size(), sizeof(int) * 3u);
EXPECT_EQ(base_byte_span.data(), reinterpret_cast<const uint8_t*>(kData));
}
}
TEST(SpanTest, ToStdSpan) {
int kData[] = {10, 11, 12};
base::span<const int> base_span(kData);
base::span<int> mut_base_span(kData);
base::span<const int, 3u> fixed_base_span(kData);
base::span<int, 3u> mut_fixed_base_span(kData);
// Tests *implicit* conversions through assignment construction.
{
std::span<const int> std_span = base_span;
EXPECT_EQ(std_span.size(), 3u);
EXPECT_EQ(std_span.data(), kData);
}
{
std::span<const int> std_span = mut_base_span;
EXPECT_EQ(std_span.size(), 3u);
EXPECT_EQ(std_span.data(), kData);
}
{
std::span<const int> std_span = fixed_base_span;
EXPECT_EQ(std_span.size(), 3u);
EXPECT_EQ(std_span.data(), kData);
}
{
std::span<const int> std_span = mut_fixed_base_span;
EXPECT_EQ(std_span.size(), 3u);
EXPECT_EQ(std_span.data(), kData);
}
{
std::span<const int, 3u> std_span = fixed_base_span;
EXPECT_EQ(std_span.size(), 3u);
EXPECT_EQ(std_span.data(), kData);
}
{
std::span<const int, 3u> std_span = mut_fixed_base_span;
EXPECT_EQ(std_span.size(), 3u);
EXPECT_EQ(std_span.data(), kData);
}
{
std::span<int, 3u> std_span = mut_fixed_base_span;
EXPECT_EQ(std_span.size(), 3u);
EXPECT_EQ(std_span.data(), kData);
}
// no make_span() or as_byte_span() in std::span.
}