From 31875e97b4e11493da07f34096bb4b89180a62b5 Mon Sep 17 00:00:00 2001
From: nobu <nobu@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
Date: Wed, 26 Aug 2009 14:58:44 +0000
Subject: [PATCH] * random.c (random_rand): fixed for edge cases of ranges.  
 [ruby-dev:39166]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@24674 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
---
 ChangeLog              |  5 +++++
 random.c               | 10 +++++++---
 test/ruby/test_rand.rb |  8 ++++++++
 3 files changed, 20 insertions(+), 3 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 37500d724e..f6074eff0d 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Wed Aug 26 23:58:39 2009  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* random.c (random_rand): fixed for edge cases of ranges.
+	  [ruby-dev:39166]
+
 Wed Aug 26 21:49:23 2009  NARUSE, Yui  <naruse@ruby-lang.org>
 
 	* lib/tempfile.rb: add documents from Hongli Lai's fork.
diff --git a/random.c b/random.c
index 3b5729f965..17e5bef3c6 100644
--- a/random.c
+++ b/random.c
@@ -760,10 +760,11 @@ make_mask(unsigned long x)
 static unsigned long
 limited_rand(struct MT *mt, unsigned long limit)
 {
-    unsigned long mask = make_mask(limit);
     int i;
-    unsigned long val;
+    unsigned long val, mask;
 
+    if (!limit) return 0;
+    mask = make_mask(limit);
   retry:
     val = 0;
     for (i = SIZEOF_LONG/SIZEOF_INT32-1; 0 <= i; i--) {
@@ -1016,7 +1017,7 @@ random_rand(int argc, VALUE *argv, VALUE obj)
 	    v = Qnil;
 	    if (FIXNUM_P(vmax)) {
 	      fixnum:
-		if ((max = FIX2LONG(vmax) - excl) > 0) {
+		if ((max = FIX2LONG(vmax) - excl) >= 0) {
 		    unsigned long r = limited_rand(&rnd->mt, (unsigned long)max);
 		    v = ULONG2NUM(r);
 		}
@@ -1042,6 +1043,9 @@ random_rand(int argc, VALUE *argv, VALUE obj)
 		}
 		v = rb_float_new(r * max);
 	    }
+	    else if (max == 0.0 && !excl) {
+		v = rb_float_new(0.0);
+	    }
 	}
     }
     else {
diff --git a/test/ruby/test_rand.rb b/test/ruby/test_rand.rb
index 446211587f..b6563954cf 100644
--- a/test/ruby/test_rand.rb
+++ b/test/ruby/test_rand.rb
@@ -199,6 +199,14 @@ class TestRand < Test::Unit::TestCase
     assert_raise(ArgumentError, '[ruby-core:24677]') { r.rand(-1) }
     assert_raise(ArgumentError, '[ruby-core:24677]') { r.rand(-1.0) }
     assert_raise(ArgumentError, '[ruby-core:24677]') { r.rand(0) }
+    assert_equal(0, r.rand(1), '[ruby-dev:39166]')
+    assert_equal(0, r.rand(0...1), '[ruby-dev:39166]')
+    assert_equal(0, r.rand(0..0), '[ruby-dev:39166]')
+    assert_equal(0.0, r.rand(0.0..0.0), '[ruby-dev:39166]')
+    assert_raise(ArgumentError, '[ruby-dev:39166]') { r.rand(0...0) }
+    assert_raise(ArgumentError, '[ruby-dev:39166]') { r.rand(0..-1) }
+    assert_raise(ArgumentError, '[ruby-dev:39166]') { r.rand(0.0...0.0) }
+    assert_raise(ArgumentError, '[ruby-dev:39166]') { r.rand(0.0...-0.1) }
   end
 
   def test_random_seed