Markus Armbruster
866859e912
Wrap roll0() around random(), and seed_prng() around srandom(). In preparation of replacing the PRNG.
86 lines
1.9 KiB
C
86 lines
1.9 KiB
C
/*
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* Empire - A multi-player, client/server Internet based war game.
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* Copyright (C) 1986-2013, Dave Pare, Jeff Bailey, Thomas Ruschak,
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* Ken Stevens, Steve McClure, Markus Armbruster
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*
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* Empire is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*
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* ---
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*
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* See files README, COPYING and CREDITS in the root of the source
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* tree for related information and legal notices. It is expected
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* that future projects/authors will amend these files as needed.
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*
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* ---
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*
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* chance.c: Roll dice
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*
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* Known contributors to this file:
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*
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*/
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#include <config.h>
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#include <math.h>
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#include <stdlib.h>
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#include "chance.h"
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/*
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* Return non-zero with probability D.
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*/
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int
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chance(double d)
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{
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return d > (random() % 32768) / 32768.0;
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}
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/*
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* Return a random number in [0..N-1].
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*/
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int
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roll0(int n)
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{
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return random() % n;
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}
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/*
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* Return a random number in [1..N].
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*/
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int
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roll(int n)
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{
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return 1 + random() % n;
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}
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/*
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* Round VAL to nearest integer (on the average).
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* VAL's fractional part is chance to round up.
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*/
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int
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roundavg(double val)
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{
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double flr = floor(val);
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return (int)(flr + chance(val - flr));
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}
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/*
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* Seed the pseudo-random number generator with SEED.
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* The sequence of pseudo-random numbers is repeatable by seeding it
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* with the same value.
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*/
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void
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seed_prng(unsigned seed)
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{
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srandom(seed);
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}
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