gitlab.com/q-dev/q-client.git@v1.0.1/Godeps/_workspace/src/gopkg.in/karalabe/cookiejar.v2/collections/prque/prque.go (about)

     1  // CookieJar - A contestant's algorithm toolbox
     2  // Copyright (c) 2013 Peter Szilagyi. All rights reserved.
     3  //
     4  // CookieJar is dual licensed: use of this source code is governed by a BSD
     5  // license that can be found in the LICENSE file. Alternatively, the CookieJar
     6  // toolbox may be used in accordance with the terms and conditions contained
     7  // in a signed written agreement between you and the author(s).
     8  
     9  // Package prque implements a priority queue data structure supporting arbitrary
    10  // value types and float priorities.
    11  //
    12  // The reasoning behind using floats for the priorities vs. ints or interfaces
    13  // was larger flexibility without sacrificing too much performance or code
    14  // complexity.
    15  //
    16  // If you would like to use a min-priority queue, simply negate the priorities.
    17  //
    18  // Internally the queue is based on the standard heap package working on a
    19  // sortable version of the block based stack.
    20  package prque
    21  
    22  import (
    23  	"container/heap"
    24  )
    25  
    26  // Priority queue data structure.
    27  type Prque struct {
    28  	cont *sstack
    29  }
    30  
    31  // Creates a new priority queue.
    32  func New() *Prque {
    33  	return &Prque{newSstack()}
    34  }
    35  
    36  // Pushes a value with a given priority into the queue, expanding if necessary.
    37  func (p *Prque) Push(data interface{}, priority float32) {
    38  	heap.Push(p.cont, &item{data, priority})
    39  }
    40  
    41  // Pops the value with the greates priority off the stack and returns it.
    42  // Currently no shrinking is done.
    43  func (p *Prque) Pop() (interface{}, float32) {
    44  	item := heap.Pop(p.cont).(*item)
    45  	return item.value, item.priority
    46  }
    47  
    48  // Pops only the item from the queue, dropping the associated priority value.
    49  func (p *Prque) PopItem() interface{} {
    50  	return heap.Pop(p.cont).(*item).value
    51  }
    52  
    53  // Checks whether the priority queue is empty.
    54  func (p *Prque) Empty() bool {
    55  	return p.cont.Len() == 0
    56  }
    57  
    58  // Returns the number of element in the priority queue.
    59  func (p *Prque) Size() int {
    60  	return p.cont.Len()
    61  }
    62  
    63  // Clears the contents of the priority queue.
    64  func (p *Prque) Reset() {
    65  	*p = *New()
    66  }