rng.h

/* Copyright (c) 2007-2014, Stefan Eilemann <eile@equalizergraphics.com>
 *
 * This library is free software; you can redistribute it and/or modify it under
 * the terms of the GNU Lesser General Public License version 2.1 as published
 * by the Free Software Foundation.
 *
 * This library 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 Lesser General Public License for more
 * details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this library; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#ifndef LUNCHBOX_RNG_H
#define LUNCHBOX_RNG_H

#include <boost/noncopyable.hpp>
#include <limits>
#include <lunchbox/debug.h> // for LBASSERT
#include <lunchbox/init.h>  // friend function
#include <lunchbox/types.h>

namespace lunchbox
{
namespace detail
{
class RNG;
}

class RNG : public boost::noncopyable
{
public:
    LUNCHBOX_API RNG();

    LUNCHBOX_API ~RNG();

    template <typename T>
    T get()
    {
        T value;
        if (!_get(&value, sizeof(T)))
            return T();
        return value;
    }

private:
    LUNCHBOX_API bool _get(void* data, size_t size);
};

template <>
inline float RNG::get()
{
    const float max_limits =
        static_cast<float>(std::numeric_limits<uint32_t>::max());
    return ((float)get<uint32_t>() / max_limits);
}

template <>
inline double RNG::get()
{
    const double max_limits =
        static_cast<double>(std::numeric_limits<uint64_t>::max());
    return ((double)get<uint64_t>() / max_limits);
}

template <>
inline bool RNG::get()
{
    return (get<uint32_t>() & 1);
}
}
#endif // LUNCHBOX_RNG_H