Setting up 3.5.0 as trunk

src/random.c

@@ -0,0 +1,91 @@
+/* ************************************************************************
+*   File: random.c                                      Part of CircleMUD *
+*  Usage: pseudo-random number generator                                  *
+************************************************************************ */
+
+/*
+ * I am bothered by the non-portablility of 'rand' and 'random' -- rand
+ * is ANSI C, but on some systems such as Suns, rand has seriously tragic
+ * spectral properties (the low bit alternates between 0 and 1!).  random
+ * is better but isn't supported by all systems.  So, in my quest for Ultimate
+ * CircleMUD Portability, I decided to include this code for a simple but
+ * relatively effective random number generator.  It's not the best RNG code
+ * around, but I like it because it's very short and simple, and for our
+ * purposes it's "random enough".
+ *               --Jeremy Elson  2/23/95
+ *
+ * Now that we're using GNU's autoconf, I've coded Circle to always use
+ * random(), and automatically link in this object file if random() isn't
+ * supported on the target system.  -JE 2/3/96
+ *
+ * Well, despite autoconf we're back to using this random all the
+ * time.  Oh well, there's no harm in changing my mind on this one
+ * from release to release...  -JE 10/28/97
+ */
+
+/***************************************************************************/
+
+/*
+ *
+ * This program is public domain and was written by William S. England
+ * (Oct 1988).  It is based on an article by:
+ *
+ * Stephen K. Park and Keith W. Miller. RANDOM NUMBER GENERATORS:
+ * GOOD ONES ARE HARD TO FIND. Communications of the ACM,
+ * New York, NY.,October 1988 p.1192
+
+ The following is a portable c program for generating random numbers.
+ The modulus and multipilier have been extensively tested and should
+ not be changed except by someone who is a professional Lehmer generator
+ writer.  THIS GENERATOR REPRESENTS THE MINIMUM STANDARD AGAINST WHICH
+ OTHER GENERATORS SHOULD BE JUDGED. ("Quote from the referenced article's
+ authors. WSE" )
+*/
+
+#define	m  (unsigned long)2147483647
+#define	q  (unsigned long)127773
+
+#define	a (unsigned int)16807
+#define	r (unsigned int)2836
+
+/*
+** F(z)	= (az)%m
+**	= az-m(az/m)
+**
+** F(z)  = G(z)+mT(z)
+** G(z)  = a(z%q)- r(z/q)
+** T(z)  = (z/q) - (az/m)
+**
+** F(z)  = a(z%q)- rz/q+ m((z/q) - a(z/m))
+** 	 = a(z%q)- rz/q+ m(z/q) - az
+*/
+
+static unsigned long seed;
+
+/* local functions */
+void circle_srandom(unsigned long initial_seed);
+unsigned long circle_random(void);
+
+
+void circle_srandom(unsigned long initial_seed)
+{
+    seed = initial_seed; 
+}
+
+
+unsigned long circle_random(void)
+{
+   int lo, hi, test;
+
+    hi   = seed/q;
+    lo   = seed%q;
+
+    test = a*lo - r*hi;
+
+    if (test > 0)
+	seed = test;
+    else
+	seed = test+ m;
+
+    return (seed);
+}