empserver/src/lib/gen/chance.c

60 lines
1.6 KiB
C

/*
* Empire - A multi-player, client/server Internet based war game.
* Copyright (C) 1986-2008, Dave Pare, Jeff Bailey, Thomas Ruschak,
* Ken Stevens, Steve McClure
*
* 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
*
* ---
*
* See files README, COPYING and CREDITS in the root of the source
* tree for related information and legal notices. It is expected
* that future projects/authors will amend these files as needed.
*
* ---
*
* chance.c: return 1 if "roll" is under the chance.
*
* Known contributors to this file:
*
*/
#include <config.h>
#include <math.h>
#include "prototypes.h"
int
chance(double d)
{
return d > (random() % 32768) / 32768.0;
}
int
roll(int n)
{
return 1 + random() % n;
}
/*
* round value to nearest int (on the average). E.g. rounds up
* with a chance proportional to the size of the fractional part.
*/
int
roundavg(double val)
{
double flr = floor(val);
return (int)(flr + chance(val - flr));
}