quakeforge/libs/util/qendian.c

/*
	qendian.c

	(description)

	Copyright (C) 1996-1997  Id Software, Inc.
	Copyright (C) 1999,2000  contributors of the QuakeForge project
	Please see the file "AUTHORS" for a list of contributors

	This program is free software; you can redistribute it and/or
	modify it under the terms of the GNU General Public License
	as published by the Free Software Foundation; either version 2
	of the License, or (at your option) any later version.

	This program is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

	See the GNU General Public License for more details.

	You should have received a copy of the GNU General Public License
	along with this program; if not, write to:

		Free Software Foundation, Inc.
		59 Temple Place - Suite 330
		Boston, MA  02111-1307, USA

	$Id$
*/

#ifdef HAVE_CONFIG_H
# include "config.h"
#endif

#include <ctype.h>

#include "QF/qendian.h"
#include "QF/qtypes.h"
#include "QF/vfile.h"

/*
					BYTE ORDER FUNCTIONS
*/

#ifndef WORDS_BIGENDIAN
qboolean    bigendien = false;;
short       (*BigShort) (short l) = ShortSwap;
short       (*LittleShort) (short l) = ShortNoSwap;
int         (*BigLong) (int l) = LongSwap;
int         (*LittleLong) (int l) = LongNoSwap;
float       (*BigFloat) (float l) = FloatSwap;
float       (*LittleFloat) (float l) = FloatNoSwap;
#else
qboolean    bigendien = true;;
short       (*BigShort) (short l) = ShortNoSwap;
short       (*LittleShort) (short l) = ShortSwap;
int         (*BigLong) (int l) = LongNoSwap;
int         (*LittleLong) (int l) = LongSwap;
float       (*BigFloat) (float l) = FloatNoSwap;
float       (*LittleFloat) (float l) = FloatSwap;
#endif

short
ShortSwap (short l)
{
	byte        b1, b2;

	b1 = l & 255;
	b2 = (l >> 8) & 255;

	return (b1 << 8) + b2;
}

short
ShortNoSwap (short l)
{
	return l;
}

int
LongSwap (int l)
{
	byte        b1, b2, b3, b4;

	b1 = l & 255;
	b2 = (l >> 8) & 255;
	b3 = (l >> 16) & 255;
	b4 = (l >> 24) & 255;

	return ((int) b1 << 24) + ((int) b2 << 16) + ((int) b3 << 8) + b4;
}

int
LongNoSwap (int l)
{
	return l;
}

float
FloatSwap (float f)
{
	union {
		float       f;
		byte        b[4];
	} dat1     , dat2;


	dat1.f = f;
	dat2.b[0] = dat1.b[3];
	dat2.b[1] = dat1.b[2];
	dat2.b[2] = dat1.b[1];
	dat2.b[3] = dat1.b[0];
	return dat2.f;
}

float
FloatNoSwap (float f)
{
	return f;
}

void
WriteFloat (VFile *file, float f)
{
	// a float in C is /defined/ to be 32 bits. byte order, can, of course
	// still make a mess.
	union {
		float       f;
		byte        b[4];
	} dat;

	dat.f = LittleFloat (f);
	Qwrite (file, dat.b, sizeof (dat.b));
}

void
WriteByte (VFile *file, int b)
{
	byte        dat = b & 0xff;
	Qwrite (file, &dat, 1);
}

void
WriteShort (VFile *file, unsigned int s)
{
	byte        dat[2];

	dat[0] = s & 0xff;
	dat[1] = (s >> 8) & 0xff;
	Qwrite (file, dat, sizeof (dat));
}

void
WriteLong (VFile *file, unsigned int l)
{
	byte        dat[4];

	dat[0] = l & 0xff;
	dat[1] = (l >> 8) & 0xff;
	dat[2] = (l >> 16) & 0xff;
	dat[3] = (l >> 24) & 0xff;
	Qwrite (file, dat, sizeof (dat));
}

float
ReadFloat (VFile *file)
{
	// a float in C is /defined/ to be 32 bits. byte order, can, of course
	// still make a mess.
	union {
		float       f;
		byte        b[4];
	} dat;

	Qread (file, dat.b, sizeof (dat.b));
	return LittleFloat (dat.f);
}

byte
ReadByte (VFile *file)
{
	byte        dat;
	Qread (file, &dat, 1);
	return dat;
}

unsigned short
ReadShort (VFile *file)
{
	byte        dat[2];

	Qread (file, dat, sizeof (dat));
	return (dat[1] << 8) | dat[0];
}

unsigned long
ReadLong (VFile *file)
{
	byte        dat[4];

	Qread (file, dat, sizeof (dat));
	return (dat[3] << 24) | (dat[2] << 16) | (dat[1] << 8) | dat[0];
}