merges r31158 from trunk into ruby_1_9_2.

--
* numeric.c (flo_round): fix inaccurate results.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_1_9_2@31790 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

5 files changed, 20 insertions, 2 deletions

diff --git a/ChangeLog b/ChangeLog
index f640b966cc..ac8001e1fa 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Wed Mar 23 08:07:33 2011  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* numeric.c (flo_round): fix inaccurate results.
+
 Wed Mar 23 00:12:16 2011  Tajima Akio <artonx@yahoo.co.jp>
 
 	* win32/win32.c: wait process real termination after reading 
diff --git a/include/ruby/intern.h b/include/ruby/intern.h
index 0f1081715d..f0cff67928 100644
--- a/include/ruby/intern.h
+++ b/include/ruby/intern.h
@@ -114,6 +114,7 @@ VALUE rb_big_plus(VALUE, VALUE);
 VALUE rb_big_minus(VALUE, VALUE);
 VALUE rb_big_mul(VALUE, VALUE);
 VALUE rb_big_div(VALUE, VALUE);
+VALUE rb_big_idiv(VALUE, VALUE);
 VALUE rb_big_modulo(VALUE, VALUE);
 VALUE rb_big_divmod(VALUE, VALUE);
 VALUE rb_big_pow(VALUE, VALUE);
diff --git a/numeric.c b/numeric.c
index 6fb50a04e6..ce5031428d 100644
--- a/numeric.c
+++ b/numeric.c
@@ -97,6 +97,9 @@ round(double x)
 }
 #endif
 
+static VALUE fix_mul(VALUE x, VALUE y);
+static VALUE int_pow(long x, unsigned long y);
+
 static ID id_coerce, id_to_i, id_eq;
 
 VALUE rb_cNumeric;
@@ -1450,7 +1453,15 @@ flo_round(int argc, VALUE *argv, VALUE num)
 	if (ndigits < 0) number = 0;
     }
     else {
-	if (ndigits < 0) number /= f;
+	if (ndigits < 0) {
+	    if (fabs(number) < f) return INT2FIX(0);
+	    if (!FIXABLE(number)) {
+		VALUE f10 = int_pow(10, -ndigits);
+		num = rb_big_idiv(rb_dbl2big(number), f10);
+		return FIXNUM_P(num) ? fix_mul(num, f10) : rb_big_mul(num, f10);
+	    }
+	    number /= f;
+	}
 	else number *= f;
 	number = round(number);
 	if (ndigits < 0) number *= f;
diff --git a/test/ruby/test_float.rb b/test/ruby/test_float.rb
index b465814140..ab5f9bdc07 100644
--- a/test/ruby/test_float.rb
+++ b/test/ruby/test_float.rb
@@ -295,6 +295,8 @@ class TestFloat < Test::Unit::TestCase
     assert_equal(1.110, 1.111.round(2))
     assert_equal(11110.0, 11111.1.round(-1))
     assert_equal(11100.0, 11111.1.round(-2))
+
+    assert_equal(10**300, 1.1e300.round(-300))
   end
 
   VS = [
diff --git a/version.h b/version.h
index 3dad4685f3..9aeb85c740 100644
--- a/version.h
+++ b/version.h
@@ -1,5 +1,5 @@
 #define RUBY_VERSION "1.9.2"
-#define RUBY_PATCHLEVEL 217
+#define RUBY_PATCHLEVEL 218
 #define RUBY_VERSION_MAJOR 1
 #define RUBY_VERSION_MINOR 9
 #define RUBY_VERSION_TEENY 1