[macruby-changes] [3013] MacRuby/trunk/random.c

[source_changes at macosforge.org]

Revision: 3013
          http://trac.macosforge.org/projects/ruby/changeset/3013
Author:   lsansonetti at apple.com
Date:     2009-11-16 11:02:11 -0800 (Mon, 16 Nov 2009)
Log Message:
-----------
Fixed Kernel#rand(nil) random float generation (patch by nagachika00 at gmail.com)

Modified Paths:
--------------
    MacRuby/trunk/random.c

Modified: MacRuby/trunk/random.c
===================================================================
--- MacRuby/trunk/random.c	2009-11-16 16:54:04 UTC (rev 3012)
+++ MacRuby/trunk/random.c	2009-11-16 19:02:11 UTC (rev 3013)
@@ -33,36 +33,18 @@
     srandomdev();
 }
 
-/*
- * #rand(0) needs to generate a float x, such as 0.0 <= x <= 1.0. However,
- * srandom() returns a long. We want to convert that long by dividing it until
- * it is <= 1.0 using its 10th power.
- * For performance reasons, long_to_float_divider() returns the 10th power of
- * the number, without calculating the number length and using pow().
- */
-static inline unsigned long
-long_to_float_divider(long val)
-{
-    unsigned long divider = 1;
-
-    while (divider <= val) {
-        divider *= 10;
-    }
-    return divider;
-}
-
 static VALUE
 random_number_with_limit(long limit)
 {
     long	val;
 
     if (limit == 0) {
-#if __LP64__
+	/*
+	 * #rand(0) needs to generate a float x, such as 0.0 <= x <= 1.0. However,
+	 * srandom() returns a long. We want to convert that long by divide by RAND_MAX
+	 */
 	val = random();
-#else
-	val = random() % (ULONG_MAX / 10);
-#endif /* !__LP64__ */
-	return DOUBLE2NUM((double)val / long_to_float_divider(val));
+	return DOUBLE2NUM((double)val / ((unsigned long)RAND_MAX+1));
     }
     else {
 	if (limit < 0) {
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