torrent/dht/closest_nodes.go

50 lines
1005 B
Go

package dht
import (
"container/heap"
)
type nodeMaxHeap struct {
IDs []string
Target string
}
func (me nodeMaxHeap) Len() int { return len(me.IDs) }
func (me nodeMaxHeap) Less(i, j int) bool {
return idDistance(me.IDs[i], me.Target).Cmp(idDistance(me.IDs[j], me.Target)) > 0
}
func (me *nodeMaxHeap) Pop() (ret interface{}) {
ret, me.IDs = me.IDs[len(me.IDs)-1], me.IDs[:len(me.IDs)-1]
return
}
func (me *nodeMaxHeap) Push(val interface{}) {
me.IDs = append(me.IDs, val.(string))
}
func (me nodeMaxHeap) Swap(i, j int) {
me.IDs[i], me.IDs[j] = me.IDs[j], me.IDs[i]
}
type closestNodesSelector struct {
closest nodeMaxHeap
k int
}
func (me *closestNodesSelector) Push(id string) {
heap.Push(&me.closest, id)
if me.closest.Len() > me.k {
heap.Pop(&me.closest)
}
}
func (me *closestNodesSelector) IDs() []string {
return me.closest.IDs
}
func newKClosestNodesSelector(k int, targetID string) (ret closestNodesSelector) {
ret.k = k
ret.closest.Target = targetID
return
}