// Copyright 2017 The Abseil Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include "absl/base/internal/endian.h"
#include <algorithm>
#include <cstdint>
#include <limits>
#include <random>
#include <vector>
#include "gtest/gtest.h"
#include "absl/base/config.h"
namespace absl {
ABSL_NAMESPACE_BEGIN
namespace {
const uint64_t kInitialNumber{0x0123456789abcdef};
const uint64_t k64Value{kInitialNumber};
const uint32_t k32Value{0x01234567};
const uint16_t k16Value{0x0123};
const int kNumValuesToTest = 1000000;
const int kRandomSeed = 12345;
#if defined(ABSL_IS_BIG_ENDIAN)
const uint64_t kInitialInNetworkOrder{kInitialNumber};
const uint64_t k64ValueLE{0xefcdab8967452301};
const uint32_t k32ValueLE{0x67452301};
const uint16_t k16ValueLE{0x2301};
const uint64_t k64ValueBE{kInitialNumber};
const uint32_t k32ValueBE{k32Value};
const uint16_t k16ValueBE{k16Value};
#elif defined(ABSL_IS_LITTLE_ENDIAN)
const uint64_t kInitialInNetworkOrder{0xefcdab8967452301};
const uint64_t k64ValueLE{kInitialNumber};
const uint32_t k32ValueLE{k32Value};
const uint16_t k16ValueLE{k16Value};
const uint64_t k64ValueBE{0xefcdab8967452301};
const uint32_t k32ValueBE{0x67452301};
const uint16_t k16ValueBE{0x2301};
#endif
std::vector<uint16_t> GenerateAllUint16Values() {
std::vector<uint16_t> result;
result.reserve(size_t{1} << (sizeof(uint16_t) * 8));
for (uint32_t i = std::numeric_limits<uint16_t>::min();
i <= std::numeric_limits<uint16_t>::max(); ++i) {
result.push_back(static_cast<uint16_t>(i));
}
return result;
}
template<typename T>
std::vector<T> GenerateRandomIntegers(size_t num_values_to_test) {
std::vector<T> result;
result.reserve(num_values_to_test);
std::mt19937_64 rng(kRandomSeed);
for (size_t i = 0; i < num_values_to_test; ++i) {
result.push_back(rng());
}
return result;
}
void ManualByteSwap(char* bytes, int length) {
if (length == 1)
return;
EXPECT_EQ(0, length % 2);
for (int i = 0; i < length / 2; ++i) {
int j = (length - 1) - i;
using std::swap;
swap(bytes[i], bytes[j]);
}
}
template<typename T>
inline T UnalignedLoad(const char* p) {
static_assert(
sizeof(T) == 1 || sizeof(T) == 2 || sizeof(T) == 4 || sizeof(T) == 8,
"Unexpected type size");
switch (sizeof(T)) {
case 1: return *reinterpret_cast<const T*>(p);
case 2:
return ABSL_INTERNAL_UNALIGNED_LOAD16(p);
case 4:
return ABSL_INTERNAL_UNALIGNED_LOAD32(p);
case 8:
return ABSL_INTERNAL_UNALIGNED_LOAD64(p);
default:
// Suppresses invalid "not all control paths return a value" on MSVC
return {};
}
}
template <typename T, typename ByteSwapper>
static void GBSwapHelper(const std::vector<T>& host_values_to_test,
const ByteSwapper& byte_swapper) {
// Test byte_swapper against a manual byte swap.
for (typename std::vector<T>::const_iterator it = host_values_to_test.begin();
it != host_values_to_test.end(); ++it) {
T host_value = *it;
char actual_value[sizeof(host_value)];
memcpy(actual_value, &host_value, sizeof(host_value));
byte_swapper(actual_value);
char expected_value[sizeof(host_value)];
memcpy(expected_value, &host_value, sizeof(host_value));
ManualByteSwap(expected_value, sizeof(host_value));
ASSERT_EQ(0, memcmp(actual_value, expected_value, sizeof(host_value)))
<< "Swap output for 0x" << std::hex << host_value << " does not match. "
<< "Expected: 0x" << UnalignedLoad<T>(expected_value) << "; "
<< "actual: 0x" << UnalignedLoad<T>(actual_value);
}
}
void Swap16(char* bytes) {
ABSL_INTERNAL_UNALIGNED_STORE16(
bytes, gbswap_16(ABSL_INTERNAL_UNALIGNED_LOAD16(bytes)));
}
void Swap32(char* bytes) {
ABSL_INTERNAL_UNALIGNED_STORE32(
bytes, gbswap_32(ABSL_INTERNAL_UNALIGNED_LOAD32(bytes)));
}
void Swap64(char* bytes) {
ABSL_INTERNAL_UNALIGNED_STORE64(
bytes, gbswap_64(ABSL_INTERNAL_UNALIGNED_LOAD64(bytes)));
}
TEST(EndianessTest, Uint16) {
GBSwapHelper(GenerateAllUint16Values(), &Swap16);
}
TEST(EndianessTest, Uint32) {
GBSwapHelper(GenerateRandomIntegers<uint32_t>(kNumValuesToTest), &Swap32);
}
TEST(EndianessTest, Uint64) {
GBSwapHelper(GenerateRandomIntegers<uint64_t>(kNumValuesToTest), &Swap64);
}
TEST(EndianessTest, ghtonll_gntohll) {
// Test that absl::ghtonl compiles correctly
uint32_t test = 0x01234567;
EXPECT_EQ(absl::gntohl(absl::ghtonl(test)), test);
uint64_t comp = absl::ghtonll(kInitialNumber);
EXPECT_EQ(comp, kInitialInNetworkOrder);
comp = absl::gntohll(kInitialInNetworkOrder);
EXPECT_EQ(comp, kInitialNumber);
// Test that htonll and ntohll are each others' inverse functions on a
// somewhat assorted batch of numbers. 37 is chosen to not be anything
// particularly nice base 2.
uint64_t value = 1;
for (int i = 0; i < 100; ++i) {
comp = absl::ghtonll(absl::gntohll(value));
EXPECT_EQ(value, comp);
comp = absl::gntohll(absl::ghtonll(value));
EXPECT_EQ(value, comp);
value *= 37;
}
}
TEST(EndianessTest, little_endian) {
// Check little_endian uint16_t.
uint64_t comp = little_endian::FromHost16(k16Value);
EXPECT_EQ(comp, k16ValueLE);
comp = little_endian::ToHost16(k16ValueLE);
EXPECT_EQ(comp, k16Value);
// Check little_endian uint32_t.
comp = little_endian::FromHost32(k32Value);
EXPECT_EQ(comp, k32ValueLE);
comp = little_endian::ToHost32(k32ValueLE);
EXPECT_EQ(comp, k32Value);
// Check little_endian uint64_t.
comp = little_endian::FromHost64(k64Value);
EXPECT_EQ(comp, k64ValueLE);
comp = little_endian::ToHost64(k64ValueLE);
EXPECT_EQ(comp, k64Value);
// Check little-endian Load and store functions.
uint16_t u16Buf;
uint32_t u32Buf;
uint64_t u64Buf;
little_endian::Store16(&u16Buf, k16Value);
EXPECT_EQ(u16Buf, k16ValueLE);
comp = little_endian::Load16(&u16Buf);
EXPECT_EQ(comp, k16Value);
little_endian::Store32(&u32Buf, k32Value);
EXPECT_EQ(u32Buf, k32ValueLE);
comp = little_endian::Load32(&u32Buf);
EXPECT_EQ(comp, k32Value);
little_endian::Store64(&u64Buf, k64Value);
EXPECT_EQ(u64Buf, k64ValueLE);
comp = little_endian::Load64(&u64Buf);
EXPECT_EQ(comp, k64Value);
}
TEST(EndianessTest, big_endian) {
// Check big-endian Load and store functions.
uint16_t u16Buf;
uint32_t u32Buf;
uint64_t u64Buf;
unsigned char buffer[10];
big_endian::Store16(&u16Buf, k16Value);
EXPECT_EQ(u16Buf, k16ValueBE);
uint64_t comp = big_endian::Load16(&u16Buf);
EXPECT_EQ(comp, k16Value);
big_endian::Store32(&u32Buf, k32Value);
EXPECT_EQ(u32Buf, k32ValueBE);
comp = big_endian::Load32(&u32Buf);
EXPECT_EQ(comp, k32Value);
big_endian::Store64(&u64Buf, k64Value);
EXPECT_EQ(u64Buf, k64ValueBE);
comp = big_endian::Load64(&u64Buf);
EXPECT_EQ(comp, k64Value);
big_endian::Store16(buffer + 1, k16Value);
EXPECT_EQ(u16Buf, k16ValueBE);
comp = big_endian::Load16(buffer + 1);
EXPECT_EQ(comp, k16Value);
big_endian::Store32(buffer + 1, k32Value);
EXPECT_EQ(u32Buf, k32ValueBE);
comp = big_endian::Load32(buffer + 1);
EXPECT_EQ(comp, k32Value);
big_endian::Store64(buffer + 1, k64Value);
EXPECT_EQ(u64Buf, k64ValueBE);
comp = big_endian::Load64(buffer + 1);
EXPECT_EQ(comp, k64Value);
}
} // namespace
ABSL_NAMESPACE_END
} // namespace absl
