50 lines
812 B
Go
50 lines
812 B
Go
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
|
|
}
|