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 <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 stat64 _stat64
	#define fstat64 _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];}

#ifdef ANDROID
#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* _pData) {return swap16(*(const u16*)_pData);}
inline u32 swap32(const u8* _pData) {return swap32(*(const u32*)_pData);}
inline u64 swap64(const u8* _pData) {return swap64(*(const u64*)_pData);}

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

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

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

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

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

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