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