def unquote_and_convert_to(text, to_charset, from_charset = "iso-8859-1", preserve_underscores=false)
return "" if text.nil?
text.gsub(/(.*?)(?:(?:=\?(.*?)\?(.)\?(.*?)\?=)|$)/) do
before = $1
from_charset = $2
quoting_method = $3
text = $4
before = convert_to(before, to_charset, from_charset) if before.length > 0
before + case quoting_method
when "q", "Q" then
unquote_quoted_printable_and_convert_to(text, to_charset, from_charset, preserve_underscores)
when "b", "B" then
unquote_base64_and_convert_to(text, to_charset, from_charset)
when nil then
""
else
raise "unknown quoting method #{quoting_method.inspect}"
end
end
end