m_swap.h

// Emacs style mode select	 -*- C++ -*- 
//-----------------------------------------------------------------------------
//
// $Id:$
//
// Copyright (C) 1993-1996 by id Software, Inc.
//
// This source is available for distribution and/or modification
// only under the terms of the DOOM Source Code License as
// published by id Software. All rights reserved.
//
// The source is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// FITNESS FOR A PARTICULAR PURPOSE. See the DOOM Source Code License
// for more details.
//
// DESCRIPTION:
//		Endianess handling, swapping 16bit and 32bit.
//
//-----------------------------------------------------------------------------


#ifndef __M_SWAP_H__
#define __M_SWAP_H__

#include <stdlib.h>

// Endianess handling.
// WAD files are stored little endian.
#ifdef WORDS_BIGENDIAN

// Swap 16bit, that is, MSB and LSB byte.
// No masking with 0xFF should be necessary. 
inline short LittleShort (short x)
{
	return (short)((((unsigned short)x)>>8) | (((unsigned short)x)<<8));
}

inline unsigned short LittleShort (unsigned short x)
{
	return (unsigned short)((x>>8) | (x<<8));
}

// Swapping 32bit.
inline unsigned int LittleLong (unsigned int x)
{
	return (unsigned int)(
		(x>>24)
		| ((x>>8) & 0xff00)
		| ((x<<8) & 0xff0000)
		| (x<<24));
}

inline int LittleLong (int x)
{
	return (int)(
		(((unsigned int)x)>>24)
		| ((((unsigned int)x)>>8) & 0xff00)
		| ((((unsigned int)x)<<8) & 0xff0000)
		| (((unsigned int)x)<<24));
}

#define BigShort(x)		(x)
#define BigLong(x)		(x)

#else

#define LittleShort(x)		(x)
#define LittleLong(x) 		(x)

#if defined(_MSC_VER)

inline short BigShort (short x)
{
	return (short)_byteswap_ushort((unsigned short)x);
}

inline unsigned short BigShort (unsigned short x)
{
	return _byteswap_ushort(x);
}

inline int BigLong (int x)
{
	return (int)_byteswap_ulong((unsigned long)x);
}

inline unsigned int BigLong (unsigned int x)
{
	return (unsigned int)_byteswap_ulong((unsigned long)x);
}
#pragma warning (default: 4035)

#else

inline short BigShort (short x)
{
	return (short)((((unsigned short)x)>>8) | (((unsigned short)x)<<8));
}

inline unsigned short BigShort (unsigned short x)
{
	return (unsigned short)((x>>8) | (x<<8));
}

inline unsigned int BigLong (unsigned int x)
{
	return (unsigned int)(
		(x>>24)
		| ((x>>8) & 0xff00)
		| ((x<<8) & 0xff0000)
		| (x<<24));
}

inline int BigLong (int x)
{
	return (int)(
		(((unsigned int)x)>>24)
		| ((((unsigned int)x)>>8) & 0xff00)
		| ((((unsigned int)x)<<8) & 0xff0000)
		| (((unsigned int)x)<<24));
}
#endif

#endif // WORDS_BIGENDIAN

#endif // __M_SWAP_H__