amf.rb

require 'net/rtmp/packet'
require 'net/rtmp/bytestream'
require 'stringio'

module Net
  class RTMP
    class AMF
      EndOfPacket = Class.new

      DECODE_DATA_TYPE = {
        0x00 => :number,
        0x01 => :boolean,
        0x02 => :string,
        0x03 => :object,
        0x04 => :movieclip,
        0x05 => :null,
        0x06 => :undefined,
        0x07 => :reference,
        0x08 => :ecma_array,
        0x09 => :object_end,
        0x0a => :strict_array,
        0x0b => :date,
        0x0c => :long_string,
        0x0d => :unsupported,
        0x0e => :record_set,
        0x0f => :xml_object,
        0x10 => :typed_object
      }
      ENCODE_DATA_TYPE = DECODE_DATA_TYPE.invert

      def initialize
        @elements = []
      end

      def parse(data)
        @elements = recursive_parse(Bytestream.new(StringIO.new(data)))
      end

      def to_a
        @elements
      end

    private
      def recursive_parse(bytestream)
        elements = []
        until bytestream.eof? || (e = next_element(bytestream)) == EndOfPacket
          elements << e
        end
        elements
      end

      def next_element(bytestream)
        data_type = DECODE_DATA_TYPE[read_data_type(bytestream)]
        value = __send__("read_#{data_type}", bytestream)
        value
      end

      def read_data_type(bytestream)
        bytestream.read_uint8
      end

      def read_length_prefixed_data(bytestream)
        length = bytestream.read_uint16_be
        bytestream.read(length)
      end

      alias_method :read_string,      :read_length_prefixed_data
      alias_method :read_long_string, :read_length_prefixed_data

      def read_number(bytestream)
        bytestream.read_double_be
      end

      def read_boolean(bytestream)
        bytestream.read_uint8 != 0
      end

      def read_object(bytestream)
        hash = {}
        until (key = read_length_prefixed_data(bytestream)) == ''
          hash[key] = next_element(bytestream)
        end
        hash
      end

      def read_null(_)
        nil
      end

      def read_object_end(_)
        EndOfPacket
      end

    end
  end
end