numeric.c: integer overflow

* numeric.c (ruby_num_interval_step_size): get rid of integer
  overflow.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@45212 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

2 files changed, 6 insertions, 2 deletions

diff --git a/numeric.c b/numeric.c
index 14ebc3b1c6..9692be96ce 100644
--- a/numeric.c
+++ b/numeric.c
@@ -1830,7 +1830,7 @@ ruby_num_interval_step_size(VALUE from, VALUE to, VALUE step, int excl)
 	if (delta < 0) {
 	    return INT2FIX(0);
 	}
-	return LONG2FIX(delta / diff + 1);
+	return ULONG2NUM(delta / diff + 1UL);
     }
     else if (RB_TYPE_P(from, T_FLOAT) || RB_TYPE_P(to, T_FLOAT) || RB_TYPE_P(step, T_FLOAT)) {
 	double n = ruby_float_step_size(NUM2DBL(from), NUM2DBL(to), NUM2DBL(step), excl);
diff --git a/test/ruby/test_numeric.rb b/test/ruby/test_numeric.rb
index 90d4d9ffea..0c9c38610c 100644
--- a/test/ruby/test_numeric.rb
+++ b/test/ruby/test_numeric.rb
@@ -251,7 +251,8 @@ class TestNumeric < Test::Unit::TestCase
   end
 
   def test_step
-    bignum = 1 << 100
+    i, bignum = 32, 1 << 30
+    bignum <<= (i <<= 1) - 32 until bignum.is_a?(Bignum)
     assert_raise(ArgumentError) { 1.step(10, 1, 0) { } }
     assert_raise(ArgumentError) { 1.step(10, 1, 0).size }
     assert_raise(ArgumentError) { 1.step(10, 0) { } }
@@ -267,6 +268,9 @@ class TestNumeric < Test::Unit::TestCase
     assert_nothing_raised { 1.step(by: nil) }
     assert_nothing_raised { 1.step(by: nil).size }
 
+    assert_equal(bignum*2+1, (-bignum).step(bignum, 1).size)
+    assert_equal(bignum*2, (-bignum).step(bignum-1, 1).size)
+
     assert_step [1, 2, 3, 4, 5, 6, 7, 8, 9, 10], [1, 10]
     assert_step [1, 2, 3, 4, 5, 6, 7, 8, 9, 10], [1, to: 10]
     assert_step [1, 2, 3, 4, 5, 6, 7, 8, 9, 10], [1, to: 10, by: nil]