PCG psudo random number generator (minimal)

pcg.go

// port of C source: http://www.pcg-random.org/download.html

type PCG32 struct {
	state, seq uint64
}

func NewPCG32(stateSeed, seq uint64) *PCG32 {
	return &PCG32{
		state: stateSeed,
		inc:   seq }
}

func (rng *PCG32) random() uint32 {
	oldState := rng.state
	rng.state = oldState*6364136223846793005 + (rng.inc | 1)
	xorShifted := uint32(((oldState >> 18) ^ oldState) >> 27)
	rot := uint32(oldState >> 59)
	return (xorShifted >> rot) | (xorShifted << ((-rot) & 31))
}