61 lines
1.4 KiB
Go
61 lines
1.4 KiB
Go
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// Copyright (C) 2018 Storj Labs, Inc.
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// See LICENSE for copying information.
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package kademlia
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import (
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"math/big"
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"storj.io/storj/pkg/pb"
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)
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// An Item is something we manage in a priority queue.
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type Item struct {
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value *pb.Node // The value of the item; arbitrary.
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priority *big.Int // The priority of the item in the queue.
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// The index is needed by update and is maintained by the heap.Interface methods.
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index int // The index of the item in the heap.
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}
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// A PriorityQueue implements heap.Interface and holds Items.
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type PriorityQueue []*Item
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// Len returns the length of the priority queue
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func (pq PriorityQueue) Len() int { return len(pq) }
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// Less does what you would think
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func (pq PriorityQueue) Less(i, j int) bool {
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// this sorts the nodes where the node popped has the closest location
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if i := pq[i].priority.Cmp(pq[j].priority); i < 0 {
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return true
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}
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return false
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}
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// Swap swaps two ints
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func (pq PriorityQueue) Swap(i, j int) {
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pq[i], pq[j] = pq[j], pq[i]
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pq[i].index = i
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pq[j].index = j
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}
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// Push adds an item to the top of the queue
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// must call heap.fix to resort
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func (pq *PriorityQueue) Push(x interface{}) {
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n := len(*pq)
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item := x.(*Item)
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item.index = n
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*pq = append(*pq, item)
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}
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// Pop returns the item with the lowest priority
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func (pq *PriorityQueue) Pop() interface{} {
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old := *pq
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n := len(old)
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item := old[n-1]
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item.index = -1 // for safety
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*pq = old[0 : n-1]
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return item
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}
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