pcg_rand.h

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/*
 * Copyright (C) 2021 Robin Gareus <robin@gareus.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.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */
 
#ifndef _pbd_pcg_rand_
#define _pbd_pcg_rand_
 
#include <stdint.h>
#include "pbd/libpbd_visibility.h"
 
namespace PBD
{
class LIBPBD_API PCGRand
{
public:
        PCGRand ();
 
        /* 32bit (0 .. 4294967295) */
        uint32_t rand_u32 ();
 
        /* uniform integer min <= rand < max */
        int rand (int max, int min = 0);
 
        /* unsigned float [0..1] */
        float rand_uf ()
        {
                return rand_u32 () / 4294967295.f;
        }
 
        /* signed float [-1..+1] */
        float rand_sf ()
        {
                return (rand_u32 () / 2147483647.5f) - 1.f;
        }
 
private:
        uint64_t _state;
        uint64_t _inc;
        int      _foo;
};
 
} // namespace PBD
 
#endif