dolphin/Source/Core/Common/CommonFuncs.h

// Copyright 2009 Dolphin Emulator Project
// Licensed under GPLv2+
// Refer to the license.txt file included.

#pragma once

#ifdef __APPLE__
#include <libkern/OSByteOrder.h>
#endif

#include <cstddef>
#include <cstring>
#include <string>
#include "Common/CommonTypes.h"

// Will fail to compile on a non-array:
template <typename T, size_t N>
constexpr size_t ArraySize(T (&arr)[N])
{
  return N;
}

#define b2(x) ((x) | ((x) >> 1))
#define b4(x) (b2(x) | (b2(x) >> 2))
#define b8(x) (b4(x) | (b4(x) >> 4))
#define b16(x) (b8(x) | (b8(x) >> 8))
#define b32(x) (b16(x) | (b16(x) >> 16))
#define ROUND_UP_POW2(x) (b32(x - 1) + 1)

#ifndef _WIN32

#include <errno.h>
#ifdef __linux__
#include <byteswap.h>
#elif defined __FreeBSD__
#include <sys/endian.h>
#endif

// go to debugger mode
#define Crash()                                                                                    \
  {                                                                                                \
    __builtin_trap();                                                                              \
  }

// GCC 4.8 defines all the rotate functions now
// Small issue with GCC's lrotl/lrotr intrinsics is they are still 32bit while we require 64bit
#ifndef _rotl
inline u32 _rotl(u32 x, int shift)
{
  shift &= 31;
  if (!shift)
    return x;
  return (x << shift) | (x >> (32 - shift));
}

inline u32 _rotr(u32 x, int shift)
{
  shift &= 31;
  if (!shift)
    return x;
  return (x >> shift) | (x << (32 - shift));
}
#endif

inline u64 _rotl64(u64 x, unsigned int shift)
{
  unsigned int n = shift % 64;
  return (x << n) | (x >> (64 - n));
}

inline u64 _rotr64(u64 x, unsigned int shift)
{
  unsigned int n = shift % 64;
  return (x >> n) | (x << (64 - n));
}

#else  // WIN32
// Function Cross-Compatibility
#define strcasecmp _stricmp
#define strncasecmp _strnicmp
#define unlink _unlink
#define vscprintf _vscprintf

// 64 bit offsets for Windows
#define fseeko _fseeki64
#define ftello _ftelli64
#define atoll _atoi64
#define stat _stat64
#define fstat _fstat64
#define fileno _fileno

extern "C" {
__declspec(dllimport) void __stdcall DebugBreak(void);
}
#define Crash()                                                                                    \
  {                                                                                                \
    DebugBreak();                                                                                  \
  }
#endif  // WIN32 ndef

// Generic function to get last error message.
// Call directly after the command or use the error num.
// This function might change the error code.
// Defined in Misc.cpp.
std::string GetLastErrorMsg();

namespace Common
{
inline u8 swap8(u8 _data)
{
  return _data;
}
inline u32 swap24(const u8* _data)
{
  return (_data[0] << 16) | (_data[1] << 8) | _data[2];
}

#if defined(ANDROID) || defined(__OpenBSD__)
#undef swap16
#undef swap32
#undef swap64
#endif

#ifdef _WIN32
inline u16 swap16(u16 _data)
{
  return _byteswap_ushort(_data);
}
inline u32 swap32(u32 _data)
{
  return _byteswap_ulong(_data);
}
inline u64 swap64(u64 _data)
{
  return _byteswap_uint64(_data);
}
#elif __linux__ && !(ANDROID && _M_ARM_64)
// Android NDK r10c has broken builtin byte swap routines
// Disabled for now.
inline u16 swap16(u16 _data)
{
  return bswap_16(_data);
}
inline u32 swap32(u32 _data)
{
  return bswap_32(_data);
}
inline u64 swap64(u64 _data)
{
  return bswap_64(_data);
}
#elif __APPLE__
inline __attribute__((always_inline)) u16 swap16(u16 _data)
{
  return OSSwapInt16(_data);
}
inline __attribute__((always_inline)) u32 swap32(u32 _data)
{
  return OSSwapInt32(_data);
}
inline __attribute__((always_inline)) u64 swap64(u64 _data)
{
  return OSSwapInt64(_data);
}
#elif __FreeBSD__
inline u16 swap16(u16 _data)
{
  return bswap16(_data);
}
inline u32 swap32(u32 _data)
{
  return bswap32(_data);
}
inline u64 swap64(u64 _data)
{
  return bswap64(_data);
}
#else
// Slow generic implementation.
inline u16 swap16(u16 data)
{
  return (data >> 8) | (data << 8);
}
inline u32 swap32(u32 data)
{
  return (swap16(data) << 16) | swap16(data >> 16);
}
inline u64 swap64(u64 data)
{
  return ((u64)swap32(data) << 32) | swap32(data >> 32);
}
#endif

inline u16 swap16(const u8* data)
{
  u16 value;
  std::memcpy(&value, data, sizeof(u16));

  return swap16(value);
}
inline u32 swap32(const u8* data)
{
  u32 value;
  std::memcpy(&value, data, sizeof(u32));

  return swap32(value);
}
inline u64 swap64(const u8* data)
{
  u64 value;
  std::memcpy(&value, data, sizeof(u64));

  return swap64(value);
}

template <int count>
void swap(u8*);

template <>
inline void swap<1>(u8* data)
{
}

template <>
inline void swap<2>(u8* data)
{
  const u16 value = swap16(data);

  std::memcpy(data, &value, sizeof(u16));
}

template <>
inline void swap<4>(u8* data)
{
  const u32 value = swap32(data);

  std::memcpy(data, &value, sizeof(u32));
}

template <>
inline void swap<8>(u8* data)
{
  const u64 value = swap64(data);

  std::memcpy(data, &value, sizeof(u64));
}

template <typename T>
inline T FromBigEndian(T data)
{
  static_assert(std::is_arithmetic<T>::value, "function only makes sense with arithmetic types");

  swap<sizeof(data)>(reinterpret_cast<u8*>(&data));
  return data;
}

}  // Namespace Common