string.c: fix capacity

* string.c (str_buf_cat): should round up the capacity by 4KiB,
  but not number of rooms.  [ruby-core:61886] [Bug #9709]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@45534 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

3 files changed, 17 insertions, 1 deletions

diff --git a/ChangeLog b/ChangeLog
index 6d1ceb6cba..309a5556fd 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Wed Apr  9 12:44:54 2014  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* string.c (str_buf_cat): should round up the capacity by 4KiB,
+	  but not number of rooms.  [ruby-core:61886] [Bug #9709]
+
 Tue Apr  8 22:55:32 2014  Akinori MUSHA  <knu@iDaemons.org>
 
 	* lib/mkmf.rb (MakeMakefile#dir_config): Improve documentation.
diff --git a/string.c b/string.c
index 511374c7b8..ccf265738e 100644
--- a/string.c
+++ b/string.c
@@ -2029,7 +2029,7 @@ str_buf_cat(VALUE str, const char *ptr, long len)
     if (capa <= total) {
 	while (total > capa) {
 	    if (capa + termlen >= LONG_MAX / 2) {
-		capa = (total + 4095) / 4096;
+		capa = (total + 4095) / 4096 * 4096;
 		break;
 	    }
 	    capa = (capa + termlen) * 2;
diff --git a/test/ruby/test_string.rb b/test/ruby/test_string.rb
index a35f6a3bb7..8366424c66 100644
--- a/test/ruby/test_string.rb
+++ b/test/ruby/test_string.rb
@@ -2252,6 +2252,17 @@ class TestString < Test::Unit::TestCase
     assert_equal(:foo, s.send(:=~, /abc/))
     assert_equal(:foo, s =~ /abc/, "should not use optimized instruction")
   end
+
+  def test_LSHIFT_neary_long_max
+    return unless @cls == String
+    assert_ruby_status([], <<-'end;', '[ruby-core:61886] [Bug #9709]')
+      begin
+        a = "a" * 0x4000_0000
+        a << "a" * 0x1_0000
+      rescue NoMemoryError
+      end
+    end;
+  end
 end
 
 class TestString2 < TestString