softrng.dm

/datum/softrng
	var/x
	var/y

/datum/softrng/New(seed = world.timeofday)
	x = round(seed) % 65536
	y = x

// xorshift16, Marsaglia2003: https://www.jstatsoft.org/article/view/v008i14
/datum/softrng/proc/rand16()
	var/t = x ^ (y << 5)
	x = y
	y = (y ^ (y >> 1)) ^ (t ^ (t >> 3))
	return y

/datum/softrng/proc/randfloat()
	return rand16() / 65535

/datum/softrng/proc/randint(lower, upper)
	return round(randfloat() * (upper - lower + 1) + lower)

/datum/softrng/proc/picklist(list/l)
	return l[randint(1, l.len)]