/
tree_node_v4.go
51 lines (41 loc) · 1.24 KB
/
tree_node_v4.go
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// Template file.
package template
import (
"math/bits"
"github.com/kentik/patricia"
)
const _leftmost32Bit = uint32(1 << 31)
type treeNodeV4 struct {
Left uint // left node index: 0 for not set
Right uint // right node index: 0 for not set
prefix uint32
prefixLength uint
TagCount int
}
// See how many bits match the input address
func (n *treeNodeV4) MatchCount(address patricia.IPv4Address) uint {
var length uint
if address.Length > n.prefixLength {
length = n.prefixLength
} else {
length = address.Length
}
matches := uint(bits.LeadingZeros32(n.prefix ^ address.Address))
if matches > length {
return length
}
return matches
}
// ShiftPrefix shifts the prefix by the input shiftCount
func (n *treeNodeV4) ShiftPrefix(shiftCount uint) {
n.prefix <<= shiftCount
n.prefixLength -= shiftCount
}
// IsLeftBitSet returns whether the leftmost bit is set
func (n *treeNodeV4) IsLeftBitSet() bool {
return n.prefix >= _leftmost32Bit
}
// MergeFromNodes updates the prefix and prefix length from the two input nodes
func (n *treeNodeV4) MergeFromNodes(left *treeNodeV4, right *treeNodeV4) {
n.prefix, n.prefixLength = patricia.MergePrefixes32(left.prefix, left.prefixLength, right.prefix, right.prefixLength)
}