Changeset 13333

Timestamp:

Dec 22, 2009, 2:35:55 PM (15 years ago)

Author:

R. Matthew Emerson

Message:

If the system has /dev/urandom, read from it to initialize the
random-state object when calling (make-random-state t).

Use different values for the intial random state.

File:

• trunk/source/level-1/l1-numbers.lisp (modified) (1 diff)

trunk/source/level-1/l1-numbers.lisp

@@ -457 +457 @@
 
 (defun random-mrg31k3p-state ()
-  (loop repeat 6
-        for n = (init-random-state-seeds)
-        ;; The first three seed elements must not be all zero, and
-        ;; likewise for the second three.  Avoid the issue by
-        ;; excluding zero values.
-        collect (1+ (mod n (1- mrg31k3p-limit))) into seed
-        finally (return (apply #'%cons-mrg31k3p-state seed))))
+  (with-open-file (stream "/dev/urandom" :element-type '(unsigned-byte 32)
+                          :if-does-not-exist nil)
+    (loop repeat 6
+          for n = (if stream (read-byte stream) (init-random-state-seeds))
+          ;; The first three seed elements must not be all zero, and
+          ;; likewise for the second three.  Avoid the issue by
+          ;; excluding zero values.
+          collect (1+ (mod n (1- mrg31k3p-limit))) into seed
+          finally (return (apply #'%cons-mrg31k3p-state seed)))))
 
 (defun initial-random-state ()
-  (initialize-mrg31k3p-state 12345 12345 12345 12345 12345 12345))
+  (initialize-mrg31k3p-state 314159 42 1776 271828 6021023 1066))
 
 (defun make-random-state (&optional state)