chunkMax = chunkLimit / len(b) * len(b)
		if chunkMax == 0 {
			chunkMax = len(b)
		}
	}
	nb := bytealg.MakeNoZero(n)[:n:n]
	bp := copy(nb, b)
	for bp < n {
		chunk := bp
		if chunk > chunkMax {
			chunk = chunkMax
		}
		bp += copy(nb[bp:], nb[:chunk])
	}
	return nb
}

// ToUpper returns a copy of the byte slice s with all Unicode letters mapped to
// their upper case.