#==============================================================================
# ** Buffer
#------------------------------------------------------------------------------
#  Esta classe lê e escreve dados binários.
#------------------------------------------------------------------------------
#  Autor: Valentine
#==============================================================================

class Buffer_Writer

  def initialize
    @write_buffer = []
    @write_pack = ''
  end

  def write_byte(byte)
    @write_buffer << byte
    @write_pack << 'c'
  end

  def write_boolean(value)
    write_byte(value ? 1 : 0)
  end

  def write_short(short)
    @write_buffer << short
    @write_pack << 's'
  end

  def write_int(int)
    @write_buffer << int
    @write_pack << 'i'
  end

  def write_long(long)
    @write_buffer << long
    # q representa um número de 64 bits, diferentemente
    #de l que representa um número de 32 bits
    @write_pack << 'q'
  end

  def write_string(str)
    write_short(str.bytesize)
    str.each_byte { |c| write_byte(c) }
  end

  def to_s
    @write_buffer.pack(@write_pack)
  end

end

#==============================================================================
# ** Buffer_Reader
#==============================================================================
class Buffer_Reader

  def initialize(str)
    @read_bytes = []
    # O método bytes não é usado, pois, nesta versão do
    #Ruby, ele retorna Enumerator em vez de Array
    str.each_byte { |c| @read_bytes << c }
    @read_pos = 0
  end

  def read_byte
    byte = @read_bytes[@read_pos]
    @read_pos += 1
    byte
  end

  def read_boolean
    read_byte == 1
  end

  def read_short
    read(2, 's')
  end

  def read_int
    read(4, 'i')
  end

  def read_long
    read(8, 'q')
  end

  def read_string
    size = read_short
    read(size, "A#{size}")
  end

  def read_time
    Time.new(read_short, read_byte, read_byte)
  end

  private

  def read(n, format)
    bytes = @read_bytes[@read_pos, @read_pos + n]
    @read_pos += n
    bytes.pack('C*').unpack(format)[0]
  end

end