    # File lib/rubygems/package/tar_reader.rb, line 36
      def each
        loop do
          return if @io.eof?

          header = Gem::Package::TarHeader.from @io
          return if header.empty?

          entry = Gem::Package::TarReader::Entry.new header, @io
          size = entry.header.size

          yield entry

          skip = (512 - (size % 512)) % 512

          if @io.respond_to? :seek then
            # avoid reading...
            @io.seek(size - entry.bytes_read, IO::SEEK_CUR)
          else
            pending = size - entry.bytes_read

            while pending > 0 do
              bread = @io.read([pending, 4096].min).size
              raise UnexpectedEOF if @io.eof?
              pending -= bread
            end
          end

          @io.read skip # discard trailing zeros

          # make sure nobody can use #read, #getc or #rewind anymore
          entry.close
        end
      end