weights[i+1] = b & 0xf
		}
	}

	// RFC 4.2.1.3.

	var weightMark [13]uint32
	weightMask := uint32(0)
	for _, w := range weights[:count] {
		if w > 12 {
			return 0, 0, r.makeError(off, "Huffman weight overflow")
		}
		weightMark[w]++
		if w > 0 {
			weightMask += 1 << (w - 1)
		}
	}
	if weightMask == 0 {
		return 0, 0, r.makeError(off, "bad Huffman weights")
	}