class Rack::Auth::Digest::Params

def self.dequote(str) # From WEBrick::HTTPUtils
  ret = (/\A"(.*)"\Z/ =~ str) ? $1 : str.dup
  ret.gsub!(/\\(.)/, "\\1")
  ret
end

def self.parse(str)
  Params[*split_header_value(str).map do |param|
    k, v = param.split('=', 2)
    [k, dequote(v)]
  end.flatten]
end

def self.split_header_value(str)
  str.scan(/\w+\=(?:"[^\"]+"|[^,]+)/n)
end

def [](k)
  super k.to_s
end

def []=(k, v)
  super k.to_s, v.to_s
end

def initialize
  super()
  yield self if block_given?
end

def quote(str) # From WEBrick::HTTPUtils
  '"' + str.gsub(/[\\\"]/o, "\\\1") + '"'
end

def to_s
  map do |k, v|
    "#{k}=#{(UNQUOTED.include?(k) ? v.to_s : quote(v))}"
  end.join(', ')
end