package struc import ( "io" "reflect" ) type Custom interface { Pack(p []byte, opt *Options) (int, error) Unpack(r io.Reader, length int, opt *Options) error Size(opt *Options) int String() string } type customFallback struct { custom Custom } func (c customFallback) Pack(p []byte, val reflect.Value, opt *Options) (int, error) { return c.custom.Pack(p, opt) } func (c customFallback) Unpack(r io.Reader, val reflect.Value, opt *Options) error { return c.custom.Unpack(r, 1, opt) } func (c customFallback) Sizeof(val reflect.Value, opt *Options) int { return c.custom.Size(opt) } func (c customFallback) String() string { return c.custom.String() }