52 lines
1.1 KiB
Go
52 lines
1.1 KiB
Go
package priopool
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// Priority pool based on implementation example from heap package.
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// Priority queue itself is not thread safe.
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// See https://cs.opensource.google/go/go/+/refs/tags/go1.17.2:src/container/heap/example_pq_test.go
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import (
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"container/heap"
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)
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type priorityQueueTask struct {
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value func()
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priority int
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index int // the index is needed by update and is maintained by the heap.Interface methods
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}
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type priorityQueue []*priorityQueueTask
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func (pq priorityQueue) Len() int { return len(pq) }
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func (pq priorityQueue) Less(i, j int) bool {
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return pq[i].priority > pq[j].priority
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}
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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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func (pq *priorityQueue) Push(x interface{}) {
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n := len(*pq)
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item := x.(*priorityQueueTask)
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item.index = n
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*pq = append(*pq, item)
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}
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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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old[n-1] = nil
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item.index = -1
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*pq = old[0 : n-1]
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return item
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}
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func (pq *priorityQueue) update(item *priorityQueueTask, value func(), priority int) {
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item.value = value
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item.priority = priority
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heap.Fix(pq, item.index)
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}
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