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/*
* Copyright (c) 2017-2019 Cisco and/or its affiliates.
* 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:
*
* http://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.
*/
#pragma once
#include <hicn/transport/portability/portability.h>
#ifndef _WIN32
#include <arpa/inet.h>
#else
#include <hicn/transport/portability/win_portability.h>
#endif
#include <cstring>
namespace utils {
namespace {
template <size_t Size>
struct uint_types_by_size;
#define GENERATOR(sz, fn) \
static TRANSPORT_ALWAYS_INLINE uint##sz##_t byteswap_gen(uint##sz##_t v) { \
return fn(v); \
} \
template <> \
struct uint_types_by_size<sz / 8> { \
using type = uint##sz##_t; \
};
GENERATOR(8, uint8_t)
#ifdef _MSC_VER
GENERATOR(64, _byteswap_uint64)
GENERATOR(32, _byteswap_ulong)
GENERATOR(16, _byteswap_ushort)
#else
GENERATOR(64, __builtin_bswap64)
GENERATOR(32, __builtin_bswap32)
GENERATOR(16, __builtin_bswap16)
#endif
template <typename T>
struct EndianInt {
static_assert(
(std::is_integral<T>::value && !std::is_same<T, bool>::value) ||
std::is_floating_point<T>::value,
"template type parameter must be non-bool integral or floating point");
static T swap(T x) {
// we implement this with memcpy because that is defined behavior in C++
// we rely on compilers to optimize away the memcpy calls
constexpr auto s = sizeof(T);
using B = typename uint_types_by_size<s>::type;
B b;
std::memcpy(&b, &x, s);
b = byteswap_gen(b);
std::memcpy(&x, &b, s);
return x;
}
static T big(T x) {
return portability::little_endian_arch ? EndianInt::swap(x) : x;
}
static T little(T x) {
return portability::big_endian_arch ? EndianInt::swap(x) : x;
}
};
} // namespace
// big* convert between native and big-endian representations
// little* convert between native and little-endian representations
// swap* convert between big-endian and little-endian representations
//
// ntohs, htons == big16
// ntohl, htonl == big32
#define GENERATOR1(fn, t, sz) \
static t fn##sz(t x) { return fn<t>(x); }
#define GENERATOR2(t, sz) \
GENERATOR1(swap, t, sz) \
GENERATOR1(big, t, sz) \
GENERATOR1(little, t, sz)
#define GENERATOR3(sz) \
GENERATOR2(uint##sz##_t, sz) \
GENERATOR2(int##sz##_t, sz)
class Endian {
public:
enum class Order : uint8_t { LITTLE, BIG };
static constexpr Order order =
portability::little_endian_arch ? Order::LITTLE : Order::BIG;
template <typename T>
static T swap(T x) {
return EndianInt<T>::swap(x);
}
template <typename T>
static T big(T x) {
return EndianInt<T>::big(x);
}
template <typename T>
static T little(T x) {
return EndianInt<T>::little(x);
}
#if !defined(__ANDROID__)
GENERATOR3(64)
GENERATOR3(32)
GENERATOR3(16)
GENERATOR3(8)
#endif
};
template <typename T>
static TRANSPORT_ALWAYS_INLINE T ntoh(T x) {
return Endian::order == Endian::Order::LITTLE ? Endian::little(x) : x;
}
template <typename T>
static TRANSPORT_ALWAYS_INLINE T hton(T x) {
return Endian::order == Endian::Order::LITTLE ? Endian::big(x) : x;
}
} // namespace utils
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