80 lines
1.8 KiB
Go
80 lines
1.8 KiB
Go
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package dht
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import (
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"container/list"
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"sort"
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)
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type RoutingTable struct {
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node Node
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buckets [numBuckets]*list.List
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}
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func NewRoutingTable(node *Node) *RoutingTable {
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var rt RoutingTable
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for i := range rt.buckets {
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rt.buckets[i] = list.New()
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}
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rt.node = *node
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return &rt
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}
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func (rt *RoutingTable) Update(node *Node) {
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prefixLength := node.id.Xor(rt.node.id).PrefixLen()
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bucket := rt.buckets[prefixLength]
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element := findInList(bucket, rt.node.id)
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if element == nil {
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if bucket.Len() <= bucketSize {
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bucket.PushBack(node)
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}
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// TODO: Handle insertion when the list is full by evicting old elements if
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// they don't respond to a ping.
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} else {
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bucket.MoveToBack(element)
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}
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}
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func (rt *RoutingTable) FindClosest(target bitmap, count int) []*Node {
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toSort := []*SortedNode{}
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prefixLength := target.Xor(rt.node.id).PrefixLen()
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bucket := rt.buckets[prefixLength]
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appendNodes(bucket.Front(), nil, &toSort, target)
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for i := 1; (prefixLength-i >= 0 || prefixLength+i < nodeIDLength*8) && len(toSort) < count; i++ {
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if prefixLength-i >= 0 {
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bucket = rt.buckets[prefixLength-i]
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appendNodes(bucket.Front(), nil, &toSort, target)
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}
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if prefixLength+i < nodeIDLength*8 {
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bucket = rt.buckets[prefixLength+i]
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appendNodes(bucket.Front(), nil, &toSort, target)
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}
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}
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sort.Sort(byXorDistance(toSort))
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nodes := []*Node{}
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for _, c := range toSort {
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nodes = append(nodes, c.node)
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}
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return nodes
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}
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func findInList(bucket *list.List, value bitmap) *list.Element {
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for curr := bucket.Front(); curr != nil; curr = curr.Next() {
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if curr.Value.(*Node).id.Equals(value) {
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return curr
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}
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}
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return nil
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}
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func appendNodes(start, end *list.Element, nodes *[]*SortedNode, target bitmap) {
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for curr := start; curr != end; curr = curr.Next() {
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node := curr.Value.(*Node)
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*nodes = append(*nodes, &SortedNode{node, node.id.Xor(target)})
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}
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}
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