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authorB. Watson <yalhcru@gmail.com>2015-05-07 16:32:32 -0400
committerB. Watson <yalhcru@gmail.com>2015-05-07 16:32:32 -0400
commit013ac7742311556022304e8b30ca170d48b3a016 (patch)
tree53faa33e75991363f1a6dcc7edc83a66b70e6995 /rogue/random.c
downloadbsd-games-extra-013ac7742311556022304e8b30ca170d48b3a016.tar.gz
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+/* $NetBSD: random.c,v 1.8 2009/08/12 08:44:45 dholland Exp $ */
+
+/*
+ * Copyright (c) 1988, 1993
+ * The Regents of the University of California. All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Timothy C. Stoehr.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ * may be used to endorse or promote products derived from this software
+ * without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <sys/cdefs.h>
+#ifndef lint
+#if 0
+static char sccsid[] = "@(#)random.c 8.1 (Berkeley) 5/31/93";
+#else
+__RCSID("$NetBSD: random.c,v 1.8 2009/08/12 08:44:45 dholland Exp $");
+#endif
+#endif /* not lint */
+
+#include "rogue.h"
+
+/*
+ * random.c
+ *
+ * This source herein may be modified and/or distributed by anybody who
+ * so desires, with the following restrictions:
+ * 1.) No portion of this notice shall be removed.
+ * 2.) Credit shall not be taken for the creation of this source.
+ * 3.) This code is not to be traded, sold, or used for personal
+ * gain or profit.
+ *
+ */
+
+static long rntb[32] = {
+ 3, 0x9a319039, 0x32d9c024, 0x9b663182, 0x5da1f342,
+ 0xde3b81e0, 0xdf0a6fb5, 0xf103bc02, 0x48f340fb, 0x7449e56b,
+ 0xbeb1dbb0, 0xab5c5918, 0x946554fd, 0x8c2e680f, 0xeb3d799f,
+ 0xb11ee0b7, 0x2d436b86, 0xda672e2a, 0x1588ca88, 0xe369735d,
+ 0x904f35f7, 0xd7158fd6, 0x6fa6f051, 0x616e6b96, 0xac94efdc,
+ 0x36413f93, 0xc622c298, 0xf5a42ab8, 0x8a88d77b, 0xf5ad9d0e,
+ 0x8999220b, 0x27fb47b9
+};
+
+static long *fptr = &rntb[4];
+static long *rptr = &rntb[1];
+static long *state = &rntb[1];
+static int rand_type = 3;
+static int rand_deg = 31;
+static int rand_sep = 3;
+static long *end_ptr = &rntb[32];
+
+static long rrandom(void);
+
+void
+srrandom(int x)
+{
+ int i;
+
+ state[0] = x;
+ if (rand_type != 0) {
+ for (i = 1; i < rand_deg; i++) {
+ state[i] = 1103515245 * state[i - 1] + 12345;
+ }
+ fptr = &state[rand_sep];
+ rptr = &state[0];
+ for (i = 0; i < 10 * rand_deg; i++) {
+ (void)rrandom();
+ }
+ }
+}
+
+static long
+rrandom(void)
+{
+ long i;
+
+ if (rand_type == 0) {
+ i = state[0] = (state[0]*1103515245 + 12345) & 0x7fffffff;
+ } else {
+ *fptr += *rptr;
+ i = (*fptr >> 1) & 0x7fffffff;
+ if (++fptr >= end_ptr) {
+ fptr = state;
+ ++rptr;
+ } else {
+ if (++rptr >= end_ptr) {
+ rptr = state;
+ }
+ }
+ }
+ return(i);
+}
+
+int
+get_rand(int x, int y)
+{
+ int r, t;
+ long lr;
+
+ if (x > y) {
+ t = y;
+ y = x;
+ x = t;
+ }
+ lr = rrandom();
+ lr &= 0x00003fffL;
+ r = (int)lr;
+ r = (r % ((y - x) + 1)) + x;
+ return(r);
+}
+
+int
+rand_percent(int percentage)
+{
+ return(get_rand(1, 100) <= percentage);
+}
+
+int
+coin_toss(void)
+{
+ return(((rrandom() & 01) ? 1 : 0));
+}