/* -*- Mode: C; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */


/*
 * fate.c
 *
 * Copyright (C) 2004 The Free Software Foundation, Inc.
 *
 * Developed by Jon Trowbridge <trow@gnu.org>
 */

/*
 * 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307
 * USA.
 */

#ifdef CONFIG_H
#include <config.h>
#endif
#include "fate.h"

#include <glib.h>
#include <stdlib.h>
#include <time.h>

void
fate_seed (unsigned seed)
{
    srandom (seed);
}

void
fate_seed_from_time (void)
{
    time_t t;
    time (&t);
    fate_seed ((unsigned) t);
}

unsigned
fate_random (unsigned N)
{
    g_return_val_if_fail (N > 1, 0);
    return random () % N;
}

double
fate_random_uniform (double a, double b)
{
    double t;
    t = random () / (double)RAND_MAX;
    return a + (b-a)*t;
}

void
fate_shuffle_ptr_array (GPtrArray *array)
{
    int i, j, N;
    g_return_if_fail (array != NULL);
    N = array->len;
    if (N < 2)
        return;
    for (i = 0; i < N-1; ++i) {
        j = i + fate_random (N-i);
        if (i != j) {
            gpointer tmp = g_ptr_array_index (array, i);
            g_ptr_array_index (array, i) = g_ptr_array_index (array, j);
            g_ptr_array_index (array, j) = tmp;
        }
    }
}