diff --git a/lib/zip/extra_field/universal_time.rb b/lib/zip/extra_field/universal_time.rb
index a1bfaab5..99838812 100644
--- a/lib/zip/extra_field/universal_time.rb
+++ b/lib/zip/extra_field/universal_time.rb
@@ -9,7 +9,8 @@ def initialize(binstr = nil)
       @mtime = nil
       @atime = nil
       @flag  = 0
-      binstr && merge(binstr)
+
+      merge(binstr) unless binstr.nil?
     end
 
     attr_reader :atime, :ctime, :mtime, :flag
@@ -63,15 +64,15 @@ def ==(other)
 
     def pack_for_local
       s = [@flag].pack('C')
-      @flag & 1 != 0 && s << [@mtime.to_i].pack('l<')
-      @flag & 2 != 0 && s << [@atime.to_i].pack('l<')
-      @flag & 4 != 0 && s << [@ctime.to_i].pack('l<')
+      s << [@mtime.to_i].pack('l<') unless @flag & 1 == 0
+      s << [@atime.to_i].pack('l<') unless @flag & 2 == 0
+      s << [@ctime.to_i].pack('l<') unless @flag & 4 == 0
       s
     end
 
     def pack_for_c_dir
       s = [@flag].pack('C')
-      @flag & 1 == 1 && s << [@mtime.to_i].pack('l<')
+      s << [@mtime.to_i].pack('l<') unless @flag & 1 == 0
       s
     end
   end