rng.hpp

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/* $Id: rng.hpp 52533 2012-01-07 02:35:17Z shadowmaster $ */
/*
   Copyright (C) 2003 by David White <dave@whitevine.net>
   Copyright (C) 2005 - 2012 by Yann Dirson <ydirson@altern.org>
   Part of the Battle for Wesnoth Project http://www.wesnoth.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.

   See the COPYING file for more details.
*/
#ifndef RNG_HPP_INCLUDED
#define RNG_HPP_INCLUDED

#include <cstddef>

#include "random.hpp"
#include "simple_rng.hpp"

#include <boost/function.hpp>

namespace rand_rng
{

class rng
{
public:
    rng();
    /**
     * Get the next random number -- from the results if available, from the
     * generator otherwise. The two should match.
     */
    int get_random();

    /**
     * Get the next random number.
     * Do not check if the random number is consistent with local seed state
     * (evantually this should be never used).
     */
    int get_random_nocheck();

    const config* get_random_results();
    void set_random_results(const config& cfg);

    void set_seed(int seed);

protected:
    int get_random_private(bool check);
    config* random();
    void set_random(config*);

private:
    config* random_;
    size_t random_child_;

    simple_rng generator_;
};

/**
 * Set the random seed for the current random number generator, sets the seed
 * as valid nd calls the new seed callback if set
 */
void set_seed(int seed);

/**
 * Mark the RNG seed as invalid
 */
void invalidate_seed();

/**
 * Function to check whether the RNG has been updated with a new seed since
 * the las invalidate_seed() call
 */
bool has_valid_seed();

/**
 * Get the last seed the RNG was seeded with in set_seed
 */
int get_last_seed();

/**
 * Set the callback for a function that will be called on subsequent set_seed
 * calls.
 * @todo needs a reliable way of clearing the callback when things don't go as
 * normal (e.g. player quit the game while the callback is set)
 */
void set_new_seed_callback(boost::function<void (int)> f);

/** @return true if the seed callback is not NULL */
bool has_new_seed_callback();

/**
 * Clear the new seed callback
 */
void clear_new_seed_callback();

} // ends rand_rng namespace

#endif