class Addressable::URI

def self.encode_component(component, character_class=
    CharacterClasses::RESERVED + CharacterClasses::UNRESERVED,
    upcase_encoded='')
  return nil if component.nil?
  begin
    if component.kind_of?(Symbol) ||
        component.kind_of?(Numeric) ||
        component.kind_of?(TrueClass) ||
        component.kind_of?(FalseClass)
      component = component.to_s
    else
      component = component.to_str
    end
  rescue TypeError, NoMethodError
    raise TypeError, "Can't convert #{component.class} into String."
  end if !component.is_a? String
  if ![String, Regexp].include?(character_class.class)
    raise TypeError,
      "Expected String or Regexp, got #{character_class.inspect}"
  end
  if character_class.kind_of?(String)
    character_class = /[^#{character_class}]/
  end
  # We can't perform regexps on invalid UTF sequences, but
  # here we need to, so switch to ASCII.
  component = component.dup
  component.force_encoding(Encoding::ASCII_8BIT)
  # Avoiding gsub! because there are edge cases with frozen strings
  component = component.gsub(character_class) do |sequence|
    SEQUENCE_UPCASED_PERCENT_ENCODING_TABLE[sequence]
  end
  if upcase_encoded.length > 0
    upcase_encoded_chars = upcase_encoded.chars.map do |char|
      SEQUENCE_ENCODING_TABLE[char]
    end
    component = component.gsub(/%(#{upcase_encoded_chars.join('|')})/,
                               &:upcase)
  end
  return component
end