/* === S Y N F I G ========================================================= */
/*! \file quick_rng.h
** \brief Template Header
**
** $Id$
**
** \legal
** Copyright (c) 2002-2005 Robert B. Quattlebaum Jr., Adrian Bentley
** Copyright (c) 2007 Chris Moore
**
** This package 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 package 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.
** \endlegal
*/
/* ========================================================================= */
/* === S T A R T =========================================================== */
#ifndef __SYNFIG_QUICK_RNG_H
#define __SYNFIG_QUICK_RNG_H
/* === H E A D E R S ======================================================= */
#include <stdint.h>
/* === M A C R O S ========================================================= */
/* === T Y P E D E F S ===================================================== */
/* === C L A S S E S & S T R U C T S ======================================= */
// A fast 32-bit linear congruential random number generator
class quick_rng
{
uint32_t next;
public:
quick_rng(uint32_t seed=0):next(seed) { }
void set_seed(uint32_t x)
{
next=x;
}
uint32_t i32()
{
static const uint32_t a(1664525);
static const uint32_t c(1013904223);
return next=next*a+c;
}
uint32_t i16()
{
return i32()>>16;
}
float f()
{
static const float m(int(65535));
return float(i16())/m;
}
uint32_t operator()(const uint32_t& m)
{
if(m==65536)
return i16();
else
if(m<=65536)
return i16()%m;
else
return i32()%m;
}
};
/* === E N D =============================================================== */
#endif