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// Copyright 2019 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/buffer_iterator.h"
#include <string.h>
#include <limits>
#include <vector>
#include "testing/gtest/include/gtest/gtest.h"
namespace base {
namespace {
struct TestStruct {
uint32_t one;
uint8_t two;
};
bool operator==(const TestStruct& lhs, const TestStruct& rhs) {
return lhs.one == rhs.one && lhs.two == rhs.two;
}
TestStruct CreateTestStruct() {
TestStruct expected;
expected.one = 0xabcdef12;
expected.two = 0x34;
return expected;
}
TEST(BufferIteratorTest, Object) {
TestStruct expected = CreateTestStruct();
char buffer[sizeof(TestStruct)];
memcpy(buffer, &expected, sizeof(buffer));
{
// Read the object.
BufferIterator<char> iterator(buffer, sizeof(buffer));
const TestStruct* actual = iterator.Object<TestStruct>();
EXPECT_EQ(expected, *actual);
}
{
// Iterator's view of the data is not large enough to read the object.
BufferIterator<char> iterator(buffer, sizeof(buffer) - 1);
const TestStruct* actual = iterator.Object<TestStruct>();
EXPECT_FALSE(actual);
}
}
TEST(BufferIteratorTest, MutableObject) {
TestStruct expected = CreateTestStruct();
char buffer[sizeof(TestStruct)];
BufferIterator<char> iterator(buffer, sizeof(buffer));
{
// Write the object.
TestStruct* actual = iterator.MutableObject<TestStruct>();
actual->one = expected.one;
actual->two = expected.two;
}
// Rewind the iterator.
iterator.Seek(0);
{
// Read the object back.
const TestStruct* actual = iterator.Object<TestStruct>();
EXPECT_EQ(expected, *actual);
}
}
TEST(BufferIteratorTest, ObjectSizeOverflow) {
char buffer[64];
BufferIterator<char> iterator(buffer, std::numeric_limits<size_t>::max());
auto* pointer = iterator.Object<uint64_t>();
EXPECT_TRUE(pointer);
iterator.Seek(iterator.total_size() - 1);
auto* invalid_pointer = iterator.Object<uint64_t>();
EXPECT_FALSE(invalid_pointer);
}
TEST(BufferIteratorTest, Span) {
TestStruct expected = CreateTestStruct();
std::vector<char> buffer(sizeof(TestStruct) * 3);
{
// Load the span with data.
BufferIterator<char> iterator(buffer);
span<TestStruct> span = iterator.MutableSpan<TestStruct>(3);
for (auto& ts : span) {
memcpy(&ts, &expected, sizeof(expected));
}
}
{
// Read the data back out.
BufferIterator<char> iterator(buffer);
const TestStruct* actual = iterator.Object<TestStruct>();
EXPECT_EQ(expected, *actual);
actual = iterator.Object<TestStruct>();
EXPECT_EQ(expected, *actual);
actual = iterator.Object<TestStruct>();
EXPECT_EQ(expected, *actual);
EXPECT_EQ(iterator.total_size(), iterator.position());
}
{
// Cannot create spans larger than there are data for.
BufferIterator<char> iterator(buffer);
span<const TestStruct> span = iterator.Span<TestStruct>(4);
EXPECT_TRUE(span.empty());
}
}
TEST(BufferIteratorTest, SpanOverflow) {
char buffer[64];
BufferIterator<char> iterator(buffer, std::numeric_limits<size_t>::max());
{
span<const uint64_t> empty_span = iterator.Span<uint64_t>(
(std::numeric_limits<size_t>::max() / sizeof(uint64_t)) + 1);
EXPECT_TRUE(empty_span.empty());
}
{
span<const uint64_t> empty_span =
iterator.Span<uint64_t>(std::numeric_limits<size_t>::max());
EXPECT_TRUE(empty_span.empty());
}
{
iterator.Seek(iterator.total_size() - 7);
span<const uint64_t> empty_span = iterator.Span<uint64_t>(1);
EXPECT_TRUE(empty_span.empty());
}
}
TEST(BufferIteratorTest, Position) {
char buffer[64];
BufferIterator<char> iterator(buffer, sizeof(buffer));
EXPECT_EQ(sizeof(buffer), iterator.total_size());
size_t position = iterator.position();
EXPECT_EQ(0u, position);
iterator.Object<uint8_t>();
EXPECT_EQ(sizeof(uint8_t), iterator.position() - position);
position = iterator.position();
iterator.Object<uint32_t>();
EXPECT_EQ(sizeof(uint32_t), iterator.position() - position);
position = iterator.position();
iterator.Seek(32);
EXPECT_EQ(32u, iterator.position());
EXPECT_EQ(sizeof(buffer), iterator.total_size());
}
TEST(BufferIteratorTest, CopyObject) {
TestStruct expected = CreateTestStruct();
constexpr int kNumCopies = 3;
char buffer[sizeof(TestStruct) * kNumCopies];
for (int i = 0; i < kNumCopies; i++)
memcpy(buffer + i * sizeof(TestStruct), &expected, sizeof(TestStruct));
BufferIterator<char> iterator(buffer);
absl::optional<TestStruct> actual;
for (int i = 0; i < kNumCopies; i++) {
actual = iterator.CopyObject<TestStruct>();
ASSERT_TRUE(actual.has_value());
EXPECT_EQ(expected, *actual);
}
actual = iterator.CopyObject<TestStruct>();
EXPECT_FALSE(actual.has_value());
}
TEST(BufferIteratorTest, SeekWithSizeConfines) {
const char buffer[] = "vindicate";
BufferIterator<const char> iterator(buffer);
iterator.Seek(5);
iterator.TruncateTo(3);
EXPECT_TRUE(iterator.Span<char>(4).empty());
std::string result;
while (const char* c = iterator.Object<char>())
result += *c;
EXPECT_EQ(result, "cat");
}
} // namespace
} // namespace base
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