MINKEY = -1
    EOO = 0
    NUMBER = 1
    STRING = 2
    OBJECT = 3
    ARRAY = 4
    BINARY = 5
    UNDEFINED = 6
    OID = 7
    BOOLEAN = 8
    DATE = 9
    NULL = 10
    REGEX = 11
    REF = 12
    CODE = 13
    SYMBOL = 14
    CODE_W_SCOPE = 15
    NUMBER_INT = 16
    TIMESTAMP = 17
    NUMBER_LONG = 18
    MAXKEY = 127


    def bson_type(o)
      case o
      when nil
        NULL
      when Integer
        NUMBER_INT
      when Float
        NUMBER
      when ByteBuffer
        BINARY
      when Code
        CODE_W_SCOPE
      when String
        STRING
      when Array
        ARRAY
      when Regexp
        REGEX
      when ObjectId
        OID
      when DBRef
        REF
      when true, false
        BOOLEAN
      when Time
        DATE
      when Hash
        OBJECT
      when Symbol
        SYMBOL
      when MaxKey
        MAXKEY
      when MinKey
        MINKEY
      when Numeric
        raise Exception, "Cannot serialize the Numeric type #{o.class} as BSON; only Fixum, Bignum, and Float are supported."
      when Date, DateTime
        raise Exception, "#{o.class} is not currently supported; " +
        "use a UTC Time instance instead."
      else
        if defined?(ActiveSupport::TimeWithZone) && o.is_a?(ActiveSupport::TimeWithZone)
          raise Exception, "ActiveSupport::TimeWithZone is not currently supported; " +
          "use a UTC Time instance instead."
        else
          raise Exception, "Cannot serialize #{o.class} as a BSON type; it either isn't supported or won't translate to BSON."
        end
      end
    end


def serialize_number_element(val, type)
      if type == NUMBER
        puts "#{val} is type #{type} and written as a double"
      else
        if val > 2**64 / 2 - 1 or val < -2**64 / 2
          raise RangeError.new("MongoDB can only handle 8-byte ints")
        end
        if val > 2**32 / 2 - 1 or val < -2**32 / 2
          puts "#{val} is type #{type} and written as a int64"
        else
          puts "#{val} is type #{type} and written as a int32"
        end
      end
    end

a = [1, 32767, 2**32 / 2 -1, 2**32, 2**33, 2**63 / 2, 2**63]

a.each do |number|
  puts "type #{bson_type(number)}"
  serialize_number_element(number, bson_type(number))
end