o.objMap[h] = obj
	o.keySlice = append(o.keySlice, h)
}

// size reports the length of o.
func (o *ObjectSet) size() int {
	return len(o.keySlice)
}

// nameMatches returns a subset of o where objects names match the given regex.
func (o *ObjectSet) nameMatches(nameRegex string) *ObjectSet {
	ret := &ObjectSet{}
	for k, v := range o.objMap {
		_, _, objName := object.FromHash(k)
		m, err := regexp.MatchString(nameRegex, objName)