AdGuardHome/internal/dhcpd/bitset.go

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package dhcpd
const bitsPerWord = 64
// bitSet is a sparse bitSet. A nil *bitSet is an empty bitSet.
type bitSet struct {
words map[uint64]uint64
}
// newBitSet returns a new bitset.
func newBitSet() (s *bitSet) {
return &bitSet{
words: map[uint64]uint64{},
}
}
// isSet returns true if the bit n is set.
func (s *bitSet) isSet(n uint64) (ok bool) {
if s == nil {
return false
}
wordIdx := n / bitsPerWord
bitIdx := n % bitsPerWord
var word uint64
word, ok = s.words[wordIdx]
return ok && word&(1<<bitIdx) != 0
}
// set sets or unsets a bit.
func (s *bitSet) set(n uint64, ok bool) {
if s == nil {
return
}
wordIdx := n / bitsPerWord
bitIdx := n % bitsPerWord
word := s.words[wordIdx]
if ok {
word |= 1 << bitIdx
} else {
word &^= 1 << bitIdx
}
s.words[wordIdx] = word
}