class FFI::StructByReference

def from_native(value, ctx)
  @struct_class.new(value)
end

def initialize(struct_class)
  unless Class === struct_class and struct_class < FFI::Struct
    raise TypeError, 'wrong type (expected subclass of FFI::Struct)'
  end
  @struct_class = struct_class
end

def native_type
  FFI::Type::POINTER
end

def to_native(value, ctx)
  return Pointer::NULL if value.nil?
  unless @struct_class === value
    raise TypeError, "wrong argument type #{value.class} (expected #{@struct_class})"
  end
  value.pointer
end