diff --git a/lib/zip/ioextras/abstract_input_stream.rb b/lib/zip/ioextras/abstract_input_stream.rb
index 721e33a..c132725 100644
--- a/lib/zip/ioextras/abstract_input_stream.rb
+++ b/lib/zip/ioextras/abstract_input_stream.rb
@@ -36,7 +36,7 @@ module Zip
                end
 
         if tbuf.nil? || tbuf.empty?
-          return nil if number_of_bytes
+          return nil if number_of_bytes&.positive?
 
           return ''
         end