/*
 *
 * Copyright (C) 2010 - DIGITEO - Michael Baudin
 * Copyright (C) 2004 - Bruno Pincon
 * Copyright (C) 1999 - G. Marsaglia
 *
 *   PURPOSE
 *      the kiss generator of G. Marsaglia
 *      generate random integers (uint) in [0, 2^32 - 1]
 *      the state is given by 4 integers (z, w, jsr, jcong)
 *
 *   NOTES
 *      The code was given by G. Marsaglia at the end of  a
 *      thread  concerning  RNG  in C in several newsgroups
 *      (whom sci.math.num-analysis) "My offer of RNG's for
 *      C  was an invitation to dance..."
 *
 *      Slight modifications by Bruno Pincon for inclusion in
 *      Scilab (added set/get state routines)
 *
 *      kiss is made of combinaison of severals  others but
 *      they  are not interfaced at the scilab level.
 *
 *      Need that it is assumed that the
 *         unsigned int arithmetic is the classic 32 bits
 *         unsigned arithmetic modulo 2^32 (ie all is exact
 *         modulo 2^32)
 *
 * 	License: This code is released under public domain.
 * 	(Compatible with CeCILL)
 */
#include <math.h>             /* to use floor    */

#include "sciprint.h"
#include "others_generators.h"
#include "localization.h"

/* The Marsaglia 's macros : */
#define znew  (z=36969*(z&65535)+(z>>16))
#define wnew  (w=18000*(w&65535)+(w>>16))
#define MWC   ((znew<<16)+wnew )
#define CONG  (jcong=69069*jcong+1234567)
#define SHR3  (jsr^=(jsr<<17), jsr^=(jsr>>13), jsr^=(jsr<<5))
#define KISS  ((MWC^CONG)+SHR3)

/*  the kiss 's state  (any int in [0,2^32-1] are OK ?) */
static unsigned int z = 362436069, w = 521288629, jsr = 123456789, jcong = 380116160;

unsigned long int kiss(void)
{
    return ( KISS );
}

int set_state_kiss(double g1, double g2, double g3, double g4)
{
    if (g1 == floor(g1) && g2 == floor(g2) &&
            g3 == floor(g3) && g4 == floor(g4) &&
            0.0 <= g1 && g1 <= 4294967295.0 &&
            0.0 <= g2 && g2 <= 4294967295.0 &&
            0.0 <= g3 && g3 <= 4294967295.0 &&
            0.0 <= g4 && g4 <= 4294967295.0 )
    {
        z = (unsigned int) g1;
        w = (unsigned int) g2;
        jsr = (unsigned int) g3;
        jcong = (unsigned int) g4;
        return ( 1 );
    }
    else
    {
        sciprint(_("Bad seeds for kiss, must be integers in [0,2^32-1]\n"));
        return ( 0 );
    }
}

void get_state_kiss(double g[])
{
    g[0] = (double) z;
    g[1] = (double) w;
    g[2] = (double) jsr;
    g[3] = (double) jcong;
}