sup

lib/sup/rfc2047.rb (2470B) - raw

 ## from: http://blade.nagaokaut.ac.jp/cgi-bin/scat.rb/ruby/ruby-talk/101949
 
 # $Id: rfc2047.rb,v 1.4 2003/04/18 20:55:56 sam Exp $
 # MODIFIED slightly by William Morgan
 #
 # An implementation of RFC 2047 decoding.
 #
 # This module depends on the iconv library by Nobuyoshi Nakada, which I've
 # heard may be distributed as a standard part of Ruby 1.8. Many thanks to him
 # for helping with building and using iconv.
 #
 # Thanks to "Josef 'Jupp' Schugt" <jupp / gmx.de> for pointing out an error with
 # stateful character sets.
 #
 # Copyright (c) Sam Roberts <sroberts / uniserve.com> 2004
 #
 # This file is distributed under the same terms as Ruby.
 
 module Rfc2047
   WORD = %r{=\?([!\#$%&'*+-/0-9A-Z\\^\`a-z{|}~]+)\?([BbQq])\?([!->@-~ ]+)\?=} # :nodoc: 'stupid ruby-mode
   WORDSEQ = %r{(#{WORD.source})\s+(?=#{WORD.source})}
 
   def Rfc2047.is_encoded? s; s =~ WORD end
 
   # Decodes a string, +from+, containing RFC 2047 encoded words into a target
   # character set, +target+. See iconv_open(3) for information on the
   # supported target encodings. If one of the encoded words cannot be
   # converted to the target encoding, it is left in its encoded form.
   def Rfc2047.decode_to(target, from)
     from = from.gsub(WORDSEQ, '\1')
     from.gsub(WORD) do
       |word|
       charset, encoding, text = $1, $2, $3
 
       # B64 or QP decode, as necessary:
       case encoding
         when 'b', 'B'
           ## Padding is optional in RFC 2047 words. Add some extra padding
           ## before decoding the base64, otherwise on Ruby 2.0 the final byte
           ## might be discarded.
           text = (text + '===').unpack('m*')[0]
 
         when 'q', 'Q'
           # RFC 2047 has a variant of quoted printable where a ' ' character
           # can be represented as an '_', rather than =32, so convert
           # any of these that we find before doing the QP decoding.
           text = text.tr("_", " ")
           text = text.unpack('M*')[0]
 
         # Don't need an else, because no other values can be matched in a
         # WORD.
       end
 
       # Handle UTF-7 specially because Ruby doesn't actually support it as
       # a normal character encoding.
       if charset == 'UTF-7'
         begin
           next text.decode_utf7.encode(target)
         rescue ArgumentError, EncodingError
           next word
         end
       end
 
       begin
         text.force_encoding(charset).encode(target)
       rescue ArgumentError, EncodingError
         word
       end
     end
   end
 end