1 files changed, 11 insertions, 2 deletions
diff --git a/ext/digest/lib/sha1.rb b/ext/digest/lib/sha1.rb
index c4ac6f66ea..c7cf51439f 100644
--- a/ext/digest/lib/sha1.rb
+++ b/ext/digest/lib/sha1.rb
@@ -7,8 +7,17 @@ require 'digest/sha1'
 
 SHA1 = Digest::SHA1
 
-class SHA1
-  def self.sha1(*args)
+class << SHA1
+  alias orig_new new
+  def new(str = nil)
+    if str
+      orig_new.update(str)
+    else
+      orig_new
+    end
+  end
+
+  def sha1(*args)
     new(*args)
   end
 end