server/src/common/util/dice.c

/* vi: set ts=2:
 *
 *	
 *	Eressea PB(E)M host Copyright (C) 1998
 *		Enno Rehling (rehling@usa.net)
 *		Christian Schlittchen (corwin@amber.kn-bremen.de)
 *		Katja Zedel (katze@felidae.kn-bremen.de)
 *		Henning Peters (faroul@beyond.kn-bremen.de)
 *
 *  based on:
 *
 * Atlantis v1.0  13 September 1993 Copyright 1993 by Russell Wallace
 * Atlantis v1.7                    Copyright 1996 by Alex Schr<EFBFBD>der
 *
 * This program may not be used, modified or distributed. It may not be
 * sold or used commercially without prior written permission from the
 * authors.
 */

#include <config.h>

#include <assert.h>
#include <stdlib.h>
#include <ctype.h>

int
dice(int count, int value)
{								/* Usage: 3d6-3d4+5 = dice(3,6)-dice(3,4)+5 */
	int d = 0, c;

	if (value<=0) return 0; /* (enno) %0 geht nicht. echt wahr. */
	if (count >= 0)
		for (c = count; c > 0; c--)
			d += rand() % value + 1;
	else
		for (c = count; c < 0; c++)
			d -= rand() % value + 1;

	return d;
}

int
dice_rand(const char *s)
{
	const char *c = s;
	int m = 0, d = 0, k = 0, multi = 1;
	int state = 1;

	for (;;) {
		if (isdigit((int)*c)) {
			k = k*10+(*c-'0');
		} else if (*c=='+' || *c=='-' || *c==0) {
			if (state==1) /* konstante k addieren */
				m+=k*multi;
			else if (state==2) { /* dDk */
				int i;
				if (k == 0) k = 6; /* 3d == 3d6 */
				for (i=0;i!=d;++i) m += (1 + rand() % k)*multi;
			}
			else assert(!"dice_rand: illegal token");
			k = d = 0;
			state = 1;
			multi = (*c=='-')?-1:1;
		} else if (*c=='d' || *c=='D') {
			if (k==0) k = 1; /* d9 == 1d9 */
			assert(state==1 || !"dice_rand: illegal token");
			d = k;
			k = 0;
			state=2;
		} else assert(!"dice_rand: illegal token");
		if (*c==0) break;
		c++;
	}
	return m;
}