ladybird/AK/Endian.h
Lenny Maiorani e6f907a155 AK: Simplify constructors and conversions from nullptr_t
Problem:
- Many constructors are defined as `{}` rather than using the ` =
  default` compiler-provided constructor.
- Some types provide an implicit conversion operator from `nullptr_t`
  instead of requiring the caller to default construct. This violates
  the C++ Core Guidelines suggestion to declare single-argument
  constructors explicit
  (https://isocpp.github.io/CppCoreGuidelines/CppCoreGuidelines#c46-by-default-declare-single-argument-constructors-explicit).

Solution:
- Change default constructors to use the compiler-provided default
  constructor.
- Remove implicit conversion operators from `nullptr_t` and change
  usage to enforce type consistency without conversion.
2021-01-12 09:11:45 +01:00

162 lines
4.8 KiB
C++

/*
* Copyright (c) 2020, the SerenityOS developers.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#pragma once
#include <AK/Forward.h>
#include <AK/Platform.h>
#if defined(AK_OS_MACOS)
# include <libkern/OSByteOrder.h>
# include <machine/endian.h>
# define htobe16(x) OSSwapHostToBigInt16(x)
# define htole16(x) OSSwapHostToLittleInt16(x)
# define be16toh(x) OSSwapBigToHostInt16(x)
# define le16toh(x) OSSwapLittleToHostInt16(x)
# define htobe32(x) OSSwapHostToBigInt32(x)
# define htole32(x) OSSwapHostToLittleInt32(x)
# define be32toh(x) OSSwapBigToHostInt32(x)
# define le32toh(x) OSSwapLittleToHostInt32(x)
# define htobe64(x) OSSwapHostToBigInt64(x)
# define htole64(x) OSSwapHostToLittleInt64(x)
# define be64toh(x) OSSwapBigToHostInt64(x)
# define le64toh(x) OSSwapLittleToHostInt64(x)
# define __BIG_ENDIAN BIG_ENDIAN
# define __LITTLE_ENDIAN LITTLE_ENDIAN
# define __BYTE_ORDER BYTE_ORDER
#endif
namespace AK {
template<typename T>
ALWAYS_INLINE constexpr T convert_between_host_and_little_endian(T value)
{
#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
return value;
#elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
if constexpr (sizeof(T) == 8)
return __builtin_bswap64(value);
if constexpr (sizeof(T) == 4)
return __builtin_bswap32(value);
if constexpr (sizeof(T) == 2)
return __builtin_bswap16(value);
if constexpr (sizeof(T) == 1)
return value;
#endif
}
template<typename T>
ALWAYS_INLINE constexpr T convert_between_host_and_big_endian(T value)
{
#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
if constexpr (sizeof(T) == 8)
return __builtin_bswap64(value);
if constexpr (sizeof(T) == 4)
return __builtin_bswap32(value);
if constexpr (sizeof(T) == 2)
return __builtin_bswap16(value);
if constexpr (sizeof(T) == 1)
return value;
#elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
return value;
#endif
}
template<typename T>
ALWAYS_INLINE T convert_between_host_and_network_endian(T value)
{
return convert_between_host_and_big_endian(value);
}
template<typename T>
class LittleEndian;
template<typename T>
InputStream& operator>>(InputStream&, LittleEndian<T>&);
template<typename T>
OutputStream& operator<<(OutputStream&, LittleEndian<T>);
template<typename T>
class [[gnu::packed]] LittleEndian {
public:
friend InputStream& operator>><T>(InputStream&, LittleEndian<T>&);
friend OutputStream& operator<<<T>(OutputStream&, LittleEndian<T>);
constexpr LittleEndian() = default;
constexpr LittleEndian(T value)
: m_value(convert_between_host_and_little_endian(value))
{
}
constexpr operator T() const { return convert_between_host_and_little_endian(m_value); }
private:
T m_value { 0 };
};
template<typename T>
class BigEndian;
template<typename T>
InputStream& operator>>(InputStream&, BigEndian<T>&);
template<typename T>
OutputStream& operator<<(OutputStream&, BigEndian<T>);
template<typename T>
class [[gnu::packed]] BigEndian {
public:
friend InputStream& operator>><T>(InputStream&, BigEndian<T>&);
friend OutputStream& operator<<<T>(OutputStream&, BigEndian<T>);
constexpr BigEndian() = default;
constexpr BigEndian(T value)
: m_value(convert_between_host_and_big_endian(value))
{
}
constexpr operator T() const { return convert_between_host_and_big_endian(m_value); }
private:
T m_value { 0 };
};
template<typename T>
using NetworkOrdered = BigEndian<T>;
}
using AK::BigEndian;
using AK::LittleEndian;
using AK::NetworkOrdered;