nobu	2013-02-24 15:33:49 +0900 (Sun, 24 Feb 2013)

  New Revision: 39466

  http://svn.ruby-lang.org/cgi-bin/viewvc.cgi?view=rev&revision=39466

  Log:
    random.c: increase limit for generic rand
    
    * random.c (rb_random_ulong_limited): limit is inclusive, but generic
      rand method should return a number less than it, so increase for the
      difference.  [ruby-core:52779] [Bug #7935]

  Modified files:
    trunk/ChangeLog
    trunk/random.c
    trunk/test/ruby/test_rand.rb

Index: ChangeLog
===================================================================
--- ChangeLog	(revision 39465)
+++ ChangeLog	(revision 39466)
@@ -1,3 +1,15 @@ https://github.com/ruby/ruby/blob/trunk/ChangeLog#L1
+Sun Feb 24 15:33:46 2013  Nobuyoshi Nakada  <nobu@r...>
+
+	* random.c (rb_random_ulong_limited): limit is inclusive, but generic
+	  rand method should return a number less than it, so increase for the
+	  difference.  [ruby-core:52779] [Bug #7935]
+
+Sun Feb 24 15:32:36 2013  Nobuyoshi Nakada  <nobu@r...>
+
+	* random.c (rb_random_ulong_limited): limit is inclusive, but generic
+	  rand method should return a number less than it, so increase for the
+	  difference.  [ruby-core:52779] [Bug #7935]
+
 Sun Feb 24 15:14:43 2013  Eric Hodel  <drbrain@s...>
 
 	* lib/net/http.rb:  Removed duplicate Accept-Encoding in Net::HTTP#get.
Index: test/ruby/test_rand.rb
===================================================================
--- test/ruby/test_rand.rb	(revision 39465)
+++ test/ruby/test_rand.rb	(revision 39466)
@@ -528,5 +528,13 @@ END https://github.com/ruby/ruby/blob/trunk/test/ruby/test_rand.rb#L528
     def (gen = Object.new).rand(*) -1 end
     e = assert_raise(RangeError) {[1,2,3].sample(random: gen)}
     assert_match(/small -1\z/, e.message, bug7903)
+
+    bug7935 = '[ruby-core:52779] [Bug #7935]'
+    class << (gen = Object.new)
+      def rand(limit) @limit = limit; 0 end
+      attr_reader :limit
+    end
+    [1, 2].sample(1, random: gen)
+    assert_equal(2, gen.limit, bug7935)
   end
 end
Index: random.c
===================================================================
--- random.c	(revision 39465)
+++ random.c	(revision 39466)
@@ -942,13 +942,26 @@ rb_random_real(VALUE obj) https://github.com/ruby/ruby/blob/trunk/random.c#L942
     return genrand_real(&rnd->mt);
 }
 
+static inline VALUE
+ulong_to_num_plus_1(unsigned long n)
+{
+#if HAVE_LONG_LONG
+    return ULL2NUM((LONG_LONG)n+1);
+#else
+    if (n >= ULONG_MAX) {
+	return rb_big_plus(ULONG2NUM(n), INT2FIX(1));
+    }
+    return ULONG2NUM(n+1);
+#endif
+}
+
 unsigned long
 rb_random_ulong_limited(VALUE obj, unsigned long limit)
 {
     rb_random_t *rnd = try_get_rnd(obj);
     if (!rnd) {
 	extern int rb_num_negative_p(VALUE);
-	VALUE lim = ULONG2NUM(limit);
+	VALUE lim = ulong_to_num_plus_1(limit);
 	VALUE v = rb_funcall2(obj, id_rand, 1, &lim);
 	unsigned long r = NUM2ULONG(v);
 	if (rb_num_negative_p(v)) {

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