class Mail::Encodings::TransferEncoding

def self.can_encode?(enc)

but it can encode binary.
that couldn't be directly transported, e.g. Base64 has 7bit output,
Override in subclasses to indicate that they can encode text

def self.can_encode?(enc)
  can_transport? enc
end

def self.can_transport?(enc)

class hierarchy is arranged e.g. Base64 < 7bit < 8bit < Binary.
And encoding's superclass can always transport it since the

def self.can_transport?(enc)
  enc && enc <= self
end

def self.compatible_input?(str)

def self.compatible_input?(str)
  true
end

def self.cost(str)

def self.cost(str)
  raise "Unimplemented"
end

def self.lowest_cost(str, encodings)

def self.lowest_cost(str, encodings)
  best = nil
  best_cost = nil
  encodings.each do |enc|
    # If the current choice cannot be transported safely, give priority
    # to other choices but allow it to be used as a fallback.
    this_cost = enc.cost(str) if enc.compatible_input?(str)
    if !best_cost || (this_cost && this_cost < best_cost)
      best_cost = this_cost
      best = enc
    elsif this_cost == best_cost
      best = enc if enc::PRIORITY < best::PRIORITY
    end
  end
  best
end

def self.negotiate(message_encoding, source_encoding, str, allowed_encodings = nil)

def self.negotiate(message_encoding, source_encoding, str, allowed_encodings = nil)
  message_encoding = Encodings.get_encoding(message_encoding) || Encodings.get_encoding('8bit')
  source_encoding  = Encodings.get_encoding(source_encoding)
  if message_encoding && source_encoding && message_encoding.can_transport?(source_encoding) && source_encoding.compatible_input?(str)
    source_encoding
  else
    renegotiate(message_encoding, source_encoding, str, allowed_encodings)
  end
end

def self.renegotiate(message_encoding, source_encoding, str, allowed_encodings = nil)

def self.renegotiate(message_encoding, source_encoding, str, allowed_encodings = nil)
  encodings = Encodings.get_all.select do |enc|
    (allowed_encodings.nil? || allowed_encodings.include?(enc)) &&
      message_encoding.can_transport?(enc) &&
      enc.can_encode?(source_encoding)
  end
  lowest_cost(str, encodings)
end

def self.to_s

def self.to_s
  self::NAME
end

Modules

Classes