module Ethon::Curls::Options

def set_option(option, value, handle, type = :easy)
  raise NameError, "Ethon::Curls::Options unknown type #{type}." unless respond_to?("#{type.to_s.downcase}_options")
  opthash=send("#{type.to_s.downcase}_options")
  raise Errors::InvalidOption.new(option) unless opthash.include?(option)
  case opthash[option][:type]
  when :none
    return if value.nil?
    value=1
    func=:long
  when :int
    return if value.nil?
    func=:long
    value=value.to_i
  when :bool
    return if value.nil?
    func=:long
    value=(value&&value!=0) ? 1 : 0
  when :time
    return if value.nil?
    func=:long
    value=value.to_i
  when :enum
    return if value.nil?
    func=:long
    value=opthash[option][:opts][value] if value.is_a? Symbol
    value=value.to_i
  when :bitmask
    return if value.nil?
    func=:long
    value=opthash[option][:opts][value] if value.is_a? Symbol
    value=value.inject(0) { |res,v| res|opthash[option][:opts][v] } if value.is_a? Array
    value=value.to_i
  when :string
    func=:string
    value=value.to_s unless value.nil?
  when :string_escape_null
    func=:string
    value=Util.escape_zero_byte(value) unless value.nil?
  when :ffipointer
    func=:ffipointer
    raise Errors::InvalidValue.new(option,value) unless value.nil? or value.is_a? FFI::Pointer
  when :curl_slist
    func=:ffipointer
    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
    func=:callback
    raise Errors::InvalidValue.new(option,value) unless value.nil? or value.is_a? Proc
  when :debug_callback
    func=:debug_callback
    raise Errors::InvalidValue.new(option,value) unless value.nil? or value.is_a? Proc
  when :off_t
    return if value.nil?
    func=:off_t
    value=value.to_i
  end
  if func==:long or func==:off_t then
      bits=FFI.type_size(:long)*8 if func==:long
      bits=FFI.type_size(:int64)*8 if func==:off_t
      tv=((value<0) ? value.abs-1 : value)
      raise Errors::InvalidValue.new(option,value) unless tv<(1<<bits)
  end
  send("#{type}_setopt_#{func}", handle, opthash[option][:opt], value)
end