module Ethon::Curls::Options

def set_option(option, value, handle, type = :easy)
  type = type.to_sym unless type.is_a?(Symbol)
  raise NameError, "Ethon::Curls::Options unknown type #{type}." unless respond_to?(OPTION_STRINGS[type])
  opthash=send(OPTION_STRINGS[type], nil)
  raise Errors::InvalidOption.new(option) unless opthash.include?(option)
  case opthash[option][:type]
  when :none
    return if value.nil?
    value=1
    va_type=:long
  when :int
    return if value.nil?
    va_type=:long
    value=value.to_i
  when :bool
    return if value.nil?
    va_type=:long
    value=(value&&value!=0) ? 1 : 0
  when :time
    return if value.nil?
    va_type=:long
    value=value.to_i
  when :enum
    return if value.nil?
    va_type=:long
    value = case value
    when Symbol
      opthash[option][:opts][value]
    when String
      opthash[option][:opts][value.to_sym]
    else
      value
    end.to_i
  when :bitmask
    return if value.nil?
    va_type=:long
    value = case value
    when Symbol
      opthash[option][:opts][value]
    when Array
      value.inject(0) { |res,v| res|opthash[option][:opts][v] }
    else
      value
    end.to_i
  when :string
    va_type=:string
    value=value.to_s unless value.nil?
  when :string_as_pointer
    va_type = :pointer
    s = ''
    s = value.to_s unless value.nil?
    value = FFI::MemoryPointer.new(:char, s.bytesize)
    value.put_bytes(0, s)
  when :string_escape_null
    va_type=:string
    value=Util.escape_zero_byte(value) unless value.nil?
  when :ffipointer
    va_type=:pointer
    raise Errors::InvalidValue.new(option,value) unless value.nil? or value.is_a? FFI::Pointer
  when :curl_slist
    va_type=:pointer
    raise Errors::InvalidValue.new(option,value) unless value.nil? or value.is_a? FFI::Pointer
  when :buffer
    raise NotImplementedError, "Ethon::Curls::Options option #{option} buffer type not implemented."
  when :dontuse_object
    raise NotImplementedError, "Ethon::Curls::Options option #{option} type not implemented."
  when :cbdata
    raise NotImplementedError, "Ethon::Curls::Options option #{option} callback data type not implemented. Use Ruby closures."
  when :callback
    va_type=:callback
    raise Errors::InvalidValue.new(option,value) unless value.nil? or value.is_a? Proc
  when :socket_callback
    va_type=:socket_callback
    raise Errors::InvalidValue.new(option,value) unless value.nil? or value.is_a? Proc
  when :timer_callback
    va_type=:timer_callback
    raise Errors::InvalidValue.new(option,value) unless value.nil? or value.is_a? Proc
  when :debug_callback
    va_type=:debug_callback
    raise Errors::InvalidValue.new(option,value) unless value.nil? or value.is_a? Proc
  when :progress_callback
    va_type=:progress_callback
    raise Errors::InvalidValue.new(option,value) unless value.nil? or value.is_a? Proc
  when :off_t
    return if value.nil?
    va_type=:int64
    value=value.to_i
  end
  if va_type==:long or va_type==:int64 then
      bits=FFI.type_size(va_type)*8
      tv=((value<0) ? value.abs-1 : value)
      raise Errors::InvalidValue.new(option,value) unless tv<(1<<bits)
  end
  send(FUNCS[type], handle, opthash[option][:opt], va_type, value)
end