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Improve FlipRightBit by doing it directly. #1610

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merged 1 commit into from
May 16, 2019
Merged

Improve FlipRightBit by doing it directly. #1610

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6 changes: 3 additions & 3 deletions storage/types.go
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Original file line number Diff line number Diff line change
Expand Up @@ -339,7 +339,8 @@ func (n *NodeID) Copy() *NodeID {

// FlipRightBit flips the ith bit from LSB
func (n *NodeID) FlipRightBit(i int) *NodeID {
n.SetBit(i, n.Bit(i)^1)
bIndex := (n.PathLenBits() - i - 1) / 8
n.Path[bIndex] ^= 1 << uint(i%8)
return n
}

Expand Down Expand Up @@ -370,8 +371,7 @@ func (n *NodeID) MaskLeft(depth int) *NodeID {
// in the binary tree (often termed sibling node).
func (n *NodeID) Neighbor() *NodeID {
height := n.PathLenBits() - n.PrefixLenBits
n.FlipRightBit(height)
return n
return n.FlipRightBit(height)
}

// Siblings returns the siblings of the given node.
Expand Down
9 changes: 8 additions & 1 deletion storage/types_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -574,7 +574,7 @@ func TestSetBit(t *testing.T) {
}
}

func TestFlipBit(t *testing.T) {
func TestFlipRightBit(t *testing.T) {
for _, tc := range []struct {
index []byte
i int
Expand Down Expand Up @@ -869,3 +869,10 @@ func BenchmarkAsKey(b *testing.B) {
_ = nID.AsKey()
}
}

func BenchmarkFlipRightBit(b *testing.B) {
nID := NewNodeIDFromHash(h2b("000102030405060708090A0B0C0D0E0F10111213"))
for i := 0; i < b.N; i++ {
nID.FlipRightBit(27)
}
}