NT4/private/inc/byteordr.hxx
2020-09-30 17:12:29 +02:00

180 lines
3.8 KiB
C++

//+--------------------------------------------------------------
//
// Microsoft Windows
// Copyright (C) Microsoft Corporation, 1992 - 1996.
//
// File: byteordr.hxx
//
// Contents: Byte swapping functions.
// These functions can swap all of the base types,
// and some special cases. There is always an
// overloaded version which accepts a pointer to the
// data, and performs a swap in place. Where possible,
// there is also an overload which returns the swapped
// value without modifying the input.
//
//---------------------------------------------------------------
#ifndef __BYTEORDER_HXX_
#define __BYTEORDER_HXX_
#include <limits.h>
//
// BYTE Byte-Swap
//
// These exist so that you can call ByteSwap(OLECHAR) without
// knowning if OLECHAR is a CHAR or a WCHAR.
inline BYTE ByteSwap( BYTE b )
{
return(b);
}
inline VOID ByteSwap( BYTE *pb )
{
*pb = ByteSwap(*pb);
}
//
// WORD Byte-Swap
//
#ifndef LOBYTE
# define LOBYTE(a) (unsigned char)((a) & ((unsigned)~0 >> sizeof(BYTE)*8 ))
# define HIBYTE(a) (unsigned char)((unsigned)(a) >> sizeof(BYTE)*8 )
# define LOWORD(a) (WORD)( (a) & ( (WORD)~0 >> sizeof(WORD)*8 ))
# define HIWORD(a) (WORD)( (WORD)(a) >> sizeof(WORD)*8 )
# define LODWORD(a) (DWORD)( (a) & ( (DWORD)~0 >> sizeof(DWORD)*8 ))
# define HIDWORD(a) (DWORD)( (DWORD)(a) >> sizeof(DWORD)*8 )
#endif // #ifndef LOBYTE
inline WORD ByteSwap( WORD w )
{
return( (USHORT) ( (LOBYTE(w) << 8 )
|
HIBYTE(w)) );
}
inline VOID ByteSwap( WORD *pw )
{
*pw = ByteSwap(*pw);
}
//
// DWORD Byte-Swap
//
#define BYTE_MASK_A_C_ 0xff00ff00
#define BYTE_MASK__B_D 0x00ff00ff
#define BYTE_MASK_AB__ 0xffff0000
#define BYTE_MASK___CD 0x0000ffff
inline DWORD ByteSwap( DWORD dwOriginal )
{
ULONG dwSwapped;
// ABCD => BADC
dwSwapped = (( (dwOriginal) & BYTE_MASK_A_C_ ) >> 8 )
|
(( (dwOriginal) & BYTE_MASK__B_D ) << 8 );
// BADC => DCBA
dwSwapped = (( dwSwapped & BYTE_MASK_AB__ ) >> 16 )
|
(( dwSwapped & BYTE_MASK___CD ) << 16 );
return( dwSwapped );
}
inline VOID ByteSwap( DWORD *pdw )
{
*pdw = ByteSwap(*pdw);
}
//
// LONGLONG Byte-Swap
//
#define BYTE_MASK_A_C_E_G_ 0xff00ff00ff00ff00
#define BYTE_MASK__B_D_F_H 0x00ff00ff00ff00ff
#define BYTE_MASK_AB__EF__ 0xffff0000ffff0000
#define BYTE_MASK___CD__GH 0x0000ffff0000ffff
#define BYTE_MASK_ABCD____ 0xffffffff00000000
#define BYTE_MASK_____EFGH 0x00000000ffffffff
inline LONGLONG ByteSwap( LONGLONG llOriginal )
{
LONGLONG llSwapped;
#ifdef _MAC
*((DWORD*) &llSwapped) = *((DWORD*) &llOriginal + 1);
*((DWORD*) &llSwapped + 1) = *((DWORD*) &llOriginal);
ByteSwap( (DWORD*) &llSwapped );
ByteSwap( (DWORD*) &llSwapped + 1 );
#else
// ABCDEFGH => BADCFEHG
llSwapped = (( (llOriginal) & BYTE_MASK_A_C_E_G_ ) >> 8 )
|
(( (llOriginal) & BYTE_MASK__B_D_F_H ) << 8 );
// BADCFEHG => DCBAHGFE
llSwapped = (( llSwapped & BYTE_MASK_AB__EF__ ) >> 16 )
|
(( llSwapped & BYTE_MASK___CD__GH ) << 16 );
// DCBAHGFE => HGFEDCBA
llSwapped = (( llSwapped & BYTE_MASK_ABCD____ ) >> 32 )
|
(( llSwapped & BYTE_MASK_____EFGH ) << 32 );
#endif
return( llSwapped );
}
inline VOID ByteSwap( LONGLONG *pll )
{
*pll = ByteSwap( *pll );
}
//
// GUID Byte-swap
//
inline VOID ByteSwap( GUID *pguid)
{
ByteSwap(&pguid->Data1);
ByteSwap(&pguid->Data2);
ByteSwap(&pguid->Data3);
}
//
// FILETIME Byte-Swap
//
inline VOID ByteSwap(FILETIME *pfileTime)
{
ByteSwap(&pfileTime->dwLowDateTime);
ByteSwap(&pfileTime->dwHighDateTime);
}
#endif // !__BYTEORDER_HXX_