/************************************************************************
 *									*
 *		    Copyright (c) 1988, David B. Wecker			*
 *			    All Rights Reserved				*
 *									*
 * This file is part of DBW_uRAY					*
 *									*
 * DBW_uRAY is distributed in the hope that it will be useful, but	*
 * WITHOUT ANY WARRANTY. No author or distributor accepts		*
 * responsibility to anyone for the consequences of using it or for	*
 * whether it serves any particular purpose or works at all, unless	*
 * he says so in writing. Refer to the DBW_uRAY General Public		*
 * License for full details.						*
 *									*
 * Everyone is granted permission to copy, modify and redistribute	*
 * DBW_uRAY, but only under the conditions described in the		*
 * DBW_uRAY General Public License. A copy of this license is		*
 * supposed to have been given to you along with DBW_uRAY so you	*
 * can know your rights and responsibilities. It should be in a file	*
 * named COPYING. Among other things, the copyright notice and this	*
 * notice must be preserved on all copies.				*
 ************************************************************************
 *									*
 * Authors:								*
 *	DBW - David B. Wecker						*
 *									*
 * Versions:								*
 *	V1.0 881023 DBW	- First released version			*
 *	V1.1 881110 DBW - Fixed scan coherence code			*
 *	V1.2 881125 DBW - Removed ALL scan coherence code (useless)	*
 *			  added "fat" extent boxes			*
 *									*
 ************************************************************************/

#include "uray.h"

/************************************************************************/
/************ random number generator (see uray.h for random table ******/
/************************************************************************/

/*
 * srandom(x)	- sets a random seed starting point (long int)
 * random()	- returns next random long int (between 0 and 0x7FFFFFFF)
 * rnd()	- return next random FLTDBL (between 0 and 1)
 */

srandom( x )
unsigned x;
    {
    register  int i;

    /* rebuild the random table */
    randtbl[ 0 ] = x;
    for( i = 1; i < 63; i++ )
	randtbl[i] = 1103515245*randtbl[i - 1] + 12345;

    fptr = &randtbl[ 1 ];
    rptr = &randtbl[ 0 ];
    }

long random()
    {
    long		i;
	
    *fptr += *rptr;
    i = (*fptr >> 1)&0x7fffffff;	/* chucking least random bit */
    if(  ++fptr  >=  end_ptr  )  {
	fptr = randtbl;
	++rptr;
	}
    else  if(  ++rptr  >=  end_ptr  )  rptr = randtbl;
    return( i );
    }

FLTDBL rnd() {
    return ((FLTDBL)random()) / 2147483647.0;
    }