Changeset 13334

Timestamp:

Dec 22, 2009, 4:28:27 PM (15 years ago)

Author:

R. Matthew Emerson

Message:

On Windows, use quasi-documented function RtlGenRandom to initialize
random state object when calling (make-random-state t).

​http://msdn.microsoft.com/en-us/library/aa387694(VS.85).aspx
​http://blogs.msdn.com/michael_howard/archive/2005/01/14/353379.aspx

File:

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

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

@@ -456 +456 @@
     (%cons-mrg31k3p-state x0 x1 x2 x3 x4 x5)))
 
+#+windows-target
+(defun random-mrg31k3p-state ()
+  (flet ((random-u32 ()
+           (%stack-block ((buf 4))
+             ;; BOOLEAN RtlGenRandom(PVOID buf, ULONG len)
+             (let ((r (external-call "SystemFunction036" :address buf
+                                     :unsigned 4 :byte)))
+               (if (plusp r)
+                 (%get-unsigned-long buf)
+                 (init-random-state-seeds))))))
+    (loop repeat 6
+          for n = (random-u32)
+          ;; 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)))))
+
+#-windows-target
 (defun random-mrg31k3p-state ()
   (with-open-file (stream "/dev/urandom" :element-type '(unsigned-byte 32)