* random.c (rand_init): ignore higher bits if all they are same as

  the lower sign bit.  [ruby-core:29292](2)

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@27255 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

3 files changed, 18 insertions, 2 deletions

diff --git a/ChangeLog b/ChangeLog
index 4da00ef7fc..74a9d3bdbf 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Thu Apr  8 07:22:05 2010  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* random.c (rand_init): ignore higher bits if all they are same as
+	  the lower sign bit.  [ruby-core:29292](2)
+
 Thu Apr  8 07:16:19 2010  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* lib/irb/cmd/help.rb (IRB::ExtendCommand::Help#execute): use RI
diff --git a/random.c b/random.c
index 02d081c51f..de047995d5 100644
--- a/random.c
+++ b/random.c
@@ -367,6 +367,7 @@ rand_init(struct MT *mt, VALUE vseed)
 {
     volatile VALUE seed;
     long blen = 0;
+    long fixnum_seed;
     int i, j, len;
     unsigned int buf0[SIZEOF_LONG / SIZEOF_INT32 * 4], *buf = buf0;
 
@@ -374,9 +375,12 @@ rand_init(struct MT *mt, VALUE vseed)
     switch (TYPE(seed)) {
       case T_FIXNUM:
 	len = 1;
-	buf[0] = (unsigned int)(FIX2ULONG(seed) & 0xffffffff);
+	fixnum_seed = FIX2LONG(seed);
+	buf[0] = (unsigned int)(fixnum_seed & 0xffffffff);
 #if SIZEOF_LONG > SIZEOF_INT32
-	if ((buf[1] = (unsigned int)(FIX2ULONG(seed) >> 32)) != 0) ++len;
+	if ((long)(int)fixnum_seed != fixnum_seed) {
+	    if ((buf[1] = (unsigned int)(fixnum_seed >> 32)) != 0) ++len;
+	}
 #endif
 	break;
       case T_BIGNUM:
diff --git a/test/ruby/test_rand.rb b/test/ruby/test_rand.rb
index 157f542dea..25c07d3288 100644
--- a/test/ruby/test_rand.rb
+++ b/test/ruby/test_rand.rb
@@ -398,4 +398,11 @@ END
     assert(st.success?)
   rescue NotImplementedError, ArgumentError
   end
+
+  def test_seed
+    bug3104 = '[ruby-core:29292]'
+    rand_1 = Random.new(-1).rand
+    assert_not_equal(rand_1, Random.new((1 << 31) -1).rand, "#{bug3104} (2)")
+    assert_not_equal(rand_1, Random.new((1 << 63) -1).rand, "#{bug3104} (2)")
+  end
 end