1 files changed, 101 insertions, 0 deletions
diff --git a/src/libs/math/random.c b/src/libs/math/random.c
new file mode 100644
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+///Copyright Paul Reiche, Fred Ford. 1992-2002
+
+/*
+ *  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.
+ */
+ 
+ /****************************************************************************
+* FILE: random.c
+* DESC: a library of random number generators for general purpose use.
+*
+* References:
+* "Random Number Generators: Good ones are hard to find" S.K.Park & K.W.Miller
+* Communications of the ACM, Vol31 Number 10, October 1988, Pp 1192-1201
+*
+* HISTORY: Created 1/23/1989
+* LAST CHANGED:
+*
+* Copyright (c) 1989, Robert Leyland and Fred Ford
+****************************************************************************/
+
+/* ----------------------------INCLUDES----------------------------------- */
+#include "mthintrn.h" /* get the externs for error checking */
+
+/* ----------------------------DEFINES------------------------------------ */
+/* constants for licongruential random number generator from CACM article
+   referenced above */
+#define A 16807 /* a relatively prime number -- also M div Q */
+#define M 2147483647L /* 0xFFFFFFFF / 2 */
+#define Q 127773L /* M div A */
+#define R 2836 /* M mod A */
+
+/* ----------------------------STATIC DATA-------------------------------- */
+
+static DWORD seed = 12345L; /* random number seed */
+
+/* ----------------------------CODE--------------------------------------- */
+
+/*****************************************************************************
+* FUNC: DWORD TFB_Random()
+*
+* DESC: random number generator
+*
+* NOTES:
+*
+* HISTORY: Created By Robert leyland
+*
+*****************************************************************************/
+
+DWORD
+TFB_Random (void)
+{
+	seed = A * (seed % Q) - R * (seed / Q);
+	if (seed > M)
+		return (seed -= M);
+	else if (seed)
+		return (seed);
+	else
+		return (seed = 1L);
+}
+
+/*****************************************************************************
+* FUNC: DWORD TFB_SeedRandom(DWORD l)
+*
+* DESC: set the seed for the random number generator to parameter "l", and
+* return the value of the previously active seed, to allow for multiple
+* random number streams.
+*
+* NOTES: if the seed is not valid it will be coerced into a valid range
+*
+* HISTORY: Created By Robert leyland
+*
+*****************************************************************************/
+
+DWORD
+TFB_SeedRandom (DWORD new_seed)
+{
+	DWORD old_seed;
+
+	/* coerce the seed to be in the range 1..M */
+	if (new_seed == 0L) /* 0 becomes 1 */
+		new_seed = 1;
+	else if (new_seed > M) /* and less than M */
+		new_seed -= M;
+
+	old_seed = seed;
+	seed = new_seed;
+	return (old_seed);
+}
+