From: "Iñaki Baz Castillo" <ibc@...>
Date: 2009-04-04T01:39:53+09:00
Subject: Problem with String encoding when modifying it in C method

Hi, I've added a method "multi_capitalize" to String class. This
method is done in C and basically modifies the string:

  "record-roUTE".multi_capitalize => "Record-Route"

The problem is that after the method execution, the new String has
ASCII-8BIT encoding, while the original string had UTF-8 (using Ruby
1.9.1).

--------------------------------------------------------------------------------
irb> hname = "record-rouTE-€"
"record-rouTE-€"

irb> hname.encoding
#<Encoding:UTF-8>

irb> hname2 = hname.multi_capitalize
"Record-Route-\xE2\x82\xAC"                <------- !!!

irb> hname2.encoding
#<Encoding:ASCII-8BIT>                     <------- !!!

irb> hname2.force_encoding("utf-8")
"Record-Route-€"

irb> hname2.encoding
#<Encoding:UTF-8>
--------------------------------------------------------------------------------

What should I add to my C method to mantain the UTF-8 codification
after the changes in the string?
Could I invoke the C "force_encoding()" function from the C code
before returning the modified string? How to invoke it?

Thanks a lot.


-- 
Iñaki Baz Castillo
<ibc@aliax.net>