func (as *asciiSet) contains(c byte) bool {
	return (as[c/32] & (1 << (c % 32))) != 0
}

// containsRune is a simplified version of strings.ContainsRune
// to avoid importing the strings package.
// We avoid bytes.ContainsRune to avoid allocating a temporary copy of s.
func containsRune(s string, r rune) bool {
	for _, c := range s {
		if c == r {
			return true
		}
	}
	return false
}

func NewChecksumWithType(alg ChecksumType, value string) *Checksum {
	if !alg.IsSet() {
		return nil
	}
	wantParts := 0
	if strings.ContainsRune(value, '-') {
		valSplit := strings.Split(value, "-")
		if len(valSplit) != 2 {
			return nil
		}
		value = valSplit[0]
		nParts, err := strconv.Atoi(valSplit[1])
		if err != nil {
			return nil

			if m.objSize == 0 {
				m.objSize = ei.V2Obj.Size
			}
			m.data = ei.V2Obj.EcM
			m.parity = ei.V2Obj.EcN
			if len(ei.V2Obj.PartNums) == 1 && !strings.ContainsRune(ei.V2Obj.MetaUsr.Etag, '-') {
				m.wantMD5 = ei.V2Obj.MetaUsr.Etag
			}
			if m.shards == 0 {
				m.shards = m.data + m.parity
			}
			idx = ei.V2Obj.EcIndex - 1