x-gzip64 decoder for Mail gem

Author: amatsuda

lib/mail/encodings/x_gzip64.rb

@@ -0,0 +1,19 @@
+# frozen_string_literal: true
+
+require 'mail/encodings/base64'
+require 'zlib'
+
+module Mail
+  module Encodings
+    class XGzip64 < Base64
+      NAME = 'x-gzip64'
+      PRIORITY = 3
+      Encodings.register(NAME, self)
+
+      def self.decode(str)
+        base64str = Utilities.decode_base64(str)
+        ActiveSupport::Gzip.decompress(base64str)
+      end
+    end
+  end
+end