Function hexVal

pkg/blob/ref.go:293–302

'0' => 0 ... 'f' => 15, else sets *bad to true.

(b byte, bad *bool)

// '0' => 0 ... 'f' => 15, else sets *bad to true.
func hexVal(b byte, bad *bool) byte {
	if '0' <= b && b <= '9' {
		return b - '0'
	}
	if 'a' <= b && b <= 'f' {
		return b - 'a' + 10
	}
	*bad = true
	return 0
}

func validDigestName(name string) bool {
	if name == "" {