Fantom-foundation/go-lachesis

// This is a duplicated and slightly modified version of "gopkg.in/karalabe/cookiejar.v2/collections/prque".

package prque

import (
    "container/heap"
)

// Prque queue data structure.
type Prque struct {
    cont *sstack
}

// New creates a new priority queue.
func New(setIndex setIndexCallback) *Prque {
    return &Prque{newSstack(setIndex)}
}

// Push pushes a value with a given priority into the queue, expanding if necessary.
func (p *Prque) Push(data interface{}, priority int64) {
    heap.Push(p.cont, &item{data, priority})
}

// Pop pops the value with the greatest priority off the stack and returns it.
// Currently no shrinking is done.
func (p *Prque) Pop() (interface{}, int64) {
    item := heap.Pop(p.cont).(*item)
    return item.value, item.priority
}

// PopItem pops only the item from the queue, dropping the associated priority value.
func (p *Prque) PopItem() interface{} {
    return heap.Pop(p.cont).(*item).value
}

// Remove removes the element with the given index.
func (p *Prque) Remove(i int) interface{} {
    if i < 0 {
        return nil
    }
    return heap.Remove(p.cont, i)
}

// Empty checks whether the priority queue is empty.
func (p *Prque) Empty() bool {
    return p.cont.Len() == 0
}

// Size returns the number of element in the priority queue.
func (p *Prque) Size() int {
    return p.cont.Len()
}

// Reset clears the contents of the priority queue.
func (p *Prque) Reset() {
    *p = *New(p.cont.setIndex)
}