source: libcaca/trunk/libee/math.c @ 89 Tweet

/*
 *   libee         ASCII-Art library
 *   Copyright (c) 2002, 2003 Sam Hocevar <sam@zoy.org>
 *                 All Rights Reserved
 *
 *   $Id: math.c 89 2003-11-09 13:32:04Z sam $
 *
 *   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 the Free Software
 *   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include "config.h"

#include <stdlib.h>

#include "ee.h"

int ee_rand(int min, int max)
{
    return min + (int)((1.0*(max-min)) * rand() / (RAND_MAX+1.0));
}

int ee_sqrt(int a)
{
    int x;

    if(a <= 0)
    {
        return 0;
    }

    x = a > 100000 ? 1000 : a > 1000 ? 100 : a > 10 ? 10 : 1;

    /* Newton's method. Three iterations would be more than enough. */
    x = (x * x + a) / x / 2;
    x = (x * x + a) / x / 2;
    x = (x * x + a) / x / 2;
    x = (x * x + a) / x / 2;

    return x;
}