in bijection-core/src/main/scala/com/twitter/bijection/ModDivInjection.scala [26:32]
override def apply(n: Int) = {
val cmod = n % modulus
val mod = if (cmod < 0) cmod + modulus else cmod
val div = n / modulus
val toNegInf = if ((n < 0) && (mod != 0)) div - 1 else div
(mod, toNegInf)
}