mirror of
https://github.com/emirpasic/gods.git
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Implements queues, LinkedListQueue and ArrayQueue
This commit is contained in:
Emir Pasic
@@ -0,0 +1,88 @@
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// Copyright (c) 2021, Aryan Ahadinia. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// Package arrayqueue implements a queue backed by array list.
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//
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// Structure is not thread safe.
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//
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// Reference: https://en.wikipedia.org/wiki/Queue_(abstract_data_type)
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package arrayqueue
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import (
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"fmt"
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"strings"
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"github.com/emirpasic/gods/lists/arraylist"
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"github.com/emirpasic/gods/queues"
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)
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// Assert Queue implementation
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var _ queues.Queue = (*Queue)(nil)
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// Queue holds elements in an array-list
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type Queue struct {
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list *arraylist.List
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}
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// New instantiates a new empty queue
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func New() *Queue {
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return &Queue{list: arraylist.New()}
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}
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// Enqueue adds a value to the end of the queue
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func (queue *Queue) Enqueue(value interface{}) {
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queue.list.Add(value)
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}
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// Dequeue removes first element of the queue and returns it, or nil if queue is empty.
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// Second return parameter is true, unless the queue was empty and there was nothing to dequeue.
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func (queue *Queue) Dequeue() (value interface{}, ok bool) {
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value, ok = queue.list.Get(0)
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if ok {
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queue.list.Remove(0)
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}
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return
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}
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// Peek returns first element of the queue without removing it, or nil if queue is empty.
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// Second return parameter is true, unless the queue was empty and there was nothing to peek.
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func (queue *Queue) Peek() (value interface{}, ok bool) {
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return queue.list.Get(0)
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}
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// Empty returns true if queue does not contain any elements.
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func (queue *Queue) Empty() bool {
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return queue.list.Empty()
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}
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// Size returns number of elements within the queue.
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func (queue *Queue) Size() int {
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return queue.list.Size()
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}
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// Clear removes all elements from the queue.
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func (queue *Queue) Clear() {
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queue.list.Clear()
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}
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// Values returns all elements in the queue (FIFO order).
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func (queue *Queue) Values() []interface{} {
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return queue.list.Values()
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}
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// String returns a string representation of container
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func (queue *Queue) String() string {
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str := "ArrayQueue\n"
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values := []string{}
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for _, value := range queue.list.Values() {
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values = append(values, fmt.Sprintf("%v", value))
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}
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str += strings.Join(values, ", ")
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return str
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}
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// Check that the index is within bounds of the list
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func (queue *Queue) withinRange(index int) bool {
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return index >= 0 && index < queue.list.Size()
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}
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@@ -0,0 +1,494 @@
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// Copyright (c) 2015, Emir Pasic. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package arrayqueue
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import (
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"encoding/json"
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"fmt"
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"strings"
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"testing"
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)
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func TestQueueEnqueue(t *testing.T) {
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queue := New()
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if actualValue := queue.Empty(); actualValue != true {
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t.Errorf("Got %v expected %v", actualValue, true)
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}
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queue.Enqueue(1)
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queue.Enqueue(2)
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queue.Enqueue(3)
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if actualValue := queue.Values(); actualValue[0].(int) != 1 || actualValue[1].(int) != 2 || actualValue[2].(int) != 3 {
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t.Errorf("Got %v expected %v", actualValue, "[1,2,3]")
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}
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if actualValue := queue.Empty(); actualValue != false {
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t.Errorf("Got %v expected %v", actualValue, false)
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}
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if actualValue := queue.Size(); actualValue != 3 {
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t.Errorf("Got %v expected %v", actualValue, 3)
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}
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if actualValue, ok := queue.Peek(); actualValue != 1 || !ok {
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t.Errorf("Got %v expected %v", actualValue, 1)
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}
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}
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func TestQueuePeek(t *testing.T) {
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queue := New()
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if actualValue, ok := queue.Peek(); actualValue != nil || ok {
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t.Errorf("Got %v expected %v", actualValue, nil)
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}
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queue.Enqueue(1)
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queue.Enqueue(2)
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queue.Enqueue(3)
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if actualValue, ok := queue.Peek(); actualValue != 1 || !ok {
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t.Errorf("Got %v expected %v", actualValue, 1)
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}
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}
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func TestQueueDequeue(t *testing.T) {
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queue := New()
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queue.Enqueue(1)
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queue.Enqueue(2)
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queue.Enqueue(3)
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queue.Dequeue()
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if actualValue, ok := queue.Peek(); actualValue != 2 || !ok {
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t.Errorf("Got %v expected %v", actualValue, 2)
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}
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if actualValue, ok := queue.Dequeue(); actualValue != 2 || !ok {
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t.Errorf("Got %v expected %v", actualValue, 2)
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}
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if actualValue, ok := queue.Dequeue(); actualValue != 3 || !ok {
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t.Errorf("Got %v expected %v", actualValue, 3)
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}
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if actualValue, ok := queue.Dequeue(); actualValue != nil || ok {
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t.Errorf("Got %v expected %v", actualValue, nil)
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}
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if actualValue := queue.Empty(); actualValue != true {
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t.Errorf("Got %v expected %v", actualValue, true)
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}
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if actualValue := queue.Values(); len(actualValue) != 0 {
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t.Errorf("Got %v expected %v", actualValue, "[]")
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}
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}
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func TestQueueIteratorOnEmpty(t *testing.T) {
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queue := New()
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it := queue.Iterator()
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for it.Next() {
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t.Errorf("Shouldn't iterate on empty queue")
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}
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}
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func TestQueueIteratorNext(t *testing.T) {
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queue := New()
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queue.Enqueue("a")
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queue.Enqueue("b")
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queue.Enqueue("c")
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it := queue.Iterator()
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count := 0
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for it.Next() {
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count++
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index := it.Index()
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value := it.Value()
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switch index {
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case 0:
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if actualValue, expectedValue := value, "a"; actualValue != expectedValue {
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t.Errorf("Got %v expected %v", actualValue, expectedValue)
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}
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case 1:
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if actualValue, expectedValue := value, "b"; actualValue != expectedValue {
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t.Errorf("Got %v expected %v", actualValue, expectedValue)
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}
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case 2:
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if actualValue, expectedValue := value, "c"; actualValue != expectedValue {
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t.Errorf("Got %v expected %v", actualValue, expectedValue)
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}
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default:
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t.Errorf("Too many")
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}
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if actualValue, expectedValue := index, count-1; actualValue != expectedValue {
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t.Errorf("Got %v expected %v", actualValue, expectedValue)
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}
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}
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if actualValue, expectedValue := count, 3; actualValue != expectedValue {
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t.Errorf("Got %v expected %v", actualValue, expectedValue)
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}
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queue.Clear()
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it = queue.Iterator()
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for it.Next() {
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t.Errorf("Shouldn't iterate on empty queue")
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}
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}
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func TestQueueIteratorPrev(t *testing.T) {
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queue := New()
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queue.Enqueue("a")
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queue.Enqueue("b")
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queue.Enqueue("c")
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it := queue.Iterator()
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for it.Next() {
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}
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count := 0
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for it.Prev() {
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count++
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index := it.Index()
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value := it.Value()
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switch index {
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case 0:
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if actualValue, expectedValue := value, "a"; actualValue != expectedValue {
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t.Errorf("Got %v expected %v", actualValue, expectedValue)
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}
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case 1:
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if actualValue, expectedValue := value, "b"; actualValue != expectedValue {
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t.Errorf("Got %v expected %v", actualValue, expectedValue)
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}
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case 2:
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if actualValue, expectedValue := value, "c"; actualValue != expectedValue {
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t.Errorf("Got %v expected %v", actualValue, expectedValue)
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}
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default:
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t.Errorf("Too many")
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}
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if actualValue, expectedValue := index, 3-count; actualValue != expectedValue {
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t.Errorf("Got %v expected %v", actualValue, expectedValue)
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}
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}
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if actualValue, expectedValue := count, 3; actualValue != expectedValue {
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t.Errorf("Got %v expected %v", actualValue, expectedValue)
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}
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}
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func TestQueueIteratorBegin(t *testing.T) {
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queue := New()
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it := queue.Iterator()
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it.Begin()
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queue.Enqueue("a")
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queue.Enqueue("b")
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queue.Enqueue("c")
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for it.Next() {
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}
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it.Begin()
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it.Next()
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if index, value := it.Index(), it.Value(); index != 0 || value != "a" {
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t.Errorf("Got %v,%v expected %v,%v", index, value, 0, "a")
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}
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}
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func TestQueueIteratorEnd(t *testing.T) {
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queue := New()
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it := queue.Iterator()
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if index := it.Index(); index != -1 {
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t.Errorf("Got %v expected %v", index, -1)
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}
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it.End()
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if index := it.Index(); index != 0 {
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t.Errorf("Got %v expected %v", index, 0)
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}
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queue.Enqueue("a")
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queue.Enqueue("b")
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queue.Enqueue("c")
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it.End()
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if index := it.Index(); index != queue.Size() {
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t.Errorf("Got %v expected %v", index, queue.Size())
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}
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it.Prev()
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if index, value := it.Index(), it.Value(); index != queue.Size()-1 || value != "c" {
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t.Errorf("Got %v,%v expected %v,%v", index, value, queue.Size()-1, "c")
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}
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}
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func TestQueueIteratorFirst(t *testing.T) {
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queue := New()
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it := queue.Iterator()
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if actualValue, expectedValue := it.First(), false; actualValue != expectedValue {
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t.Errorf("Got %v expected %v", actualValue, expectedValue)
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}
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queue.Enqueue("a")
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queue.Enqueue("b")
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queue.Enqueue("c")
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if actualValue, expectedValue := it.First(), true; actualValue != expectedValue {
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t.Errorf("Got %v expected %v", actualValue, expectedValue)
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}
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if index, value := it.Index(), it.Value(); index != 0 || value != "a" {
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t.Errorf("Got %v,%v expected %v,%v", index, value, 0, "a")
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}
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}
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func TestQueueIteratorLast(t *testing.T) {
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queue := New()
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it := queue.Iterator()
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if actualValue, expectedValue := it.Last(), false; actualValue != expectedValue {
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t.Errorf("Got %v expected %v", actualValue, expectedValue)
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}
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queue.Enqueue("a")
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queue.Enqueue("b")
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queue.Enqueue("c")
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if actualValue, expectedValue := it.Last(), true; actualValue != expectedValue {
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t.Errorf("Got %v expected %v", actualValue, expectedValue)
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}
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if index, value := it.Index(), it.Value(); index != 2 || value != "c" {
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t.Errorf("Got %v,%v expected %v,%v", index, value, 2, "c")
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}
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}
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func TestQueueIteratorNextTo(t *testing.T) {
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// Sample seek function, i.e. string starting with "b"
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seek := func(index int, value interface{}) bool {
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return strings.HasSuffix(value.(string), "b")
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}
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// NextTo (empty)
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{
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queue := New()
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it := queue.Iterator()
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for it.NextTo(seek) {
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t.Errorf("Shouldn't iterate on empty queue")
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}
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}
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// NextTo (not found)
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{
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queue := New()
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queue.Enqueue("xx")
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queue.Enqueue("yy")
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it := queue.Iterator()
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for it.NextTo(seek) {
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t.Errorf("Shouldn't iterate on empty queue")
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}
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}
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// NextTo (found)
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{
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queue := New()
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queue.Enqueue("aa")
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queue.Enqueue("bb")
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queue.Enqueue("cc")
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it := queue.Iterator()
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it.Begin()
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if !it.NextTo(seek) {
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t.Errorf("Shouldn't iterate on empty queue")
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}
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if index, value := it.Index(), it.Value(); index != 1 || value.(string) != "bb" {
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t.Errorf("Got %v,%v expected %v,%v", index, value, 1, "bb")
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}
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if !it.Next() {
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t.Errorf("Should go to first element")
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}
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if index, value := it.Index(), it.Value(); index != 2 || value.(string) != "cc" {
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t.Errorf("Got %v,%v expected %v,%v", index, value, 2, "cc")
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}
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if it.Next() {
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t.Errorf("Should not go past last element")
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}
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}
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}
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func TestQueueIteratorPrevTo(t *testing.T) {
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// Sample seek function, i.e. string starting with "b"
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seek := func(index int, value interface{}) bool {
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return strings.HasSuffix(value.(string), "b")
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}
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// PrevTo (empty)
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{
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queue := New()
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it := queue.Iterator()
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it.End()
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for it.PrevTo(seek) {
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t.Errorf("Shouldn't iterate on empty queue")
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}
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}
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// PrevTo (not found)
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{
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queue := New()
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queue.Enqueue("xx")
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queue.Enqueue("yy")
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it := queue.Iterator()
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it.End()
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for it.PrevTo(seek) {
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t.Errorf("Shouldn't iterate on empty queue")
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}
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}
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// PrevTo (found)
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{
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queue := New()
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queue.Enqueue("aa")
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queue.Enqueue("bb")
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queue.Enqueue("cc")
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it := queue.Iterator()
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it.End()
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if !it.PrevTo(seek) {
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t.Errorf("Shouldn't iterate on empty queue")
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}
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if index, value := it.Index(), it.Value(); index != 1 || value.(string) != "bb" {
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t.Errorf("Got %v,%v expected %v,%v", index, value, 1, "bb")
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}
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if !it.Prev() {
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t.Errorf("Should go to first element")
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}
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if index, value := it.Index(), it.Value(); index != 0 || value.(string) != "aa" {
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t.Errorf("Got %v,%v expected %v,%v", index, value, 0, "aa")
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}
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if it.Prev() {
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t.Errorf("Should not go before first element")
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}
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}
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}
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func TestQueueSerialization(t *testing.T) {
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queue := New()
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queue.Enqueue("a")
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queue.Enqueue("b")
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queue.Enqueue("c")
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var err error
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assert := func() {
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if actualValue, expectedValue := fmt.Sprintf("%s%s%s", queue.Values()...), "abc"; actualValue != expectedValue {
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t.Errorf("Got %v expected %v", actualValue, expectedValue)
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}
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if actualValue, expectedValue := queue.Size(), 3; actualValue != expectedValue {
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t.Errorf("Got %v expected %v", actualValue, expectedValue)
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}
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if err != nil {
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t.Errorf("Got error %v", err)
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}
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}
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assert()
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bytes, err := queue.ToJSON()
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assert()
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err = queue.FromJSON(bytes)
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assert()
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bytes, err = json.Marshal([]interface{}{"a", "b", "c", queue})
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if err != nil {
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t.Errorf("Got error %v", err)
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}
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err = json.Unmarshal([]byte(`[1,2,3]`), &queue)
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if err != nil {
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t.Errorf("Got error %v", err)
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}
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}
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func TestQueueString(t *testing.T) {
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c := New()
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c.Enqueue(1)
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if !strings.HasPrefix(c.String(), "ArrayQueue") {
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t.Errorf("String should start with container name")
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}
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}
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func benchmarkEnqueue(b *testing.B, queue *Queue, size int) {
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for i := 0; i < b.N; i++ {
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for n := 0; n < size; n++ {
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queue.Enqueue(n)
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}
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}
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}
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|
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func benchmarkDequeue(b *testing.B, queue *Queue, size int) {
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for i := 0; i < b.N; i++ {
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for n := 0; n < size; n++ {
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queue.Dequeue()
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}
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}
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}
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func BenchmarkArrayQueueDequeue100(b *testing.B) {
|
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b.StopTimer()
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size := 100
|
||||
queue := New()
|
||||
for n := 0; n < size; n++ {
|
||||
queue.Enqueue(n)
|
||||
}
|
||||
b.StartTimer()
|
||||
benchmarkDequeue(b, queue, size)
|
||||
}
|
||||
|
||||
func BenchmarkArrayQueueDequeue1000(b *testing.B) {
|
||||
b.StopTimer()
|
||||
size := 1000
|
||||
queue := New()
|
||||
for n := 0; n < size; n++ {
|
||||
queue.Enqueue(n)
|
||||
}
|
||||
b.StartTimer()
|
||||
benchmarkDequeue(b, queue, size)
|
||||
}
|
||||
|
||||
func BenchmarkArrayQueueDequeue10000(b *testing.B) {
|
||||
b.StopTimer()
|
||||
size := 10000
|
||||
queue := New()
|
||||
for n := 0; n < size; n++ {
|
||||
queue.Enqueue(n)
|
||||
}
|
||||
b.StartTimer()
|
||||
benchmarkDequeue(b, queue, size)
|
||||
}
|
||||
|
||||
func BenchmarkArrayQueueDequeue100000(b *testing.B) {
|
||||
b.StopTimer()
|
||||
size := 100000
|
||||
queue := New()
|
||||
for n := 0; n < size; n++ {
|
||||
queue.Enqueue(n)
|
||||
}
|
||||
b.StartTimer()
|
||||
benchmarkDequeue(b, queue, size)
|
||||
}
|
||||
|
||||
func BenchmarkArrayQueueEnqueue100(b *testing.B) {
|
||||
b.StopTimer()
|
||||
size := 100
|
||||
queue := New()
|
||||
b.StartTimer()
|
||||
benchmarkEnqueue(b, queue, size)
|
||||
}
|
||||
|
||||
func BenchmarkArrayQueueEnqueue1000(b *testing.B) {
|
||||
b.StopTimer()
|
||||
size := 1000
|
||||
queue := New()
|
||||
for n := 0; n < size; n++ {
|
||||
queue.Enqueue(n)
|
||||
}
|
||||
b.StartTimer()
|
||||
benchmarkEnqueue(b, queue, size)
|
||||
}
|
||||
|
||||
func BenchmarkArrayQueueEnqueue10000(b *testing.B) {
|
||||
b.StopTimer()
|
||||
size := 10000
|
||||
queue := New()
|
||||
for n := 0; n < size; n++ {
|
||||
queue.Enqueue(n)
|
||||
}
|
||||
b.StartTimer()
|
||||
benchmarkEnqueue(b, queue, size)
|
||||
}
|
||||
|
||||
func BenchmarkArrayQueueEnqueue100000(b *testing.B) {
|
||||
b.StopTimer()
|
||||
size := 100000
|
||||
queue := New()
|
||||
for n := 0; n < size; n++ {
|
||||
queue.Enqueue(n)
|
||||
}
|
||||
b.StartTimer()
|
||||
benchmarkEnqueue(b, queue, size)
|
||||
}
|
||||
@@ -0,0 +1,111 @@
|
||||
// Copyright (c) 2021, Aryan Ahadinia. All rights reserved.
|
||||
// Use of this source code is governed by a BSD-style
|
||||
// license that can be found in the LICENSE file.
|
||||
|
||||
package arrayqueue
|
||||
|
||||
import "github.com/emirpasic/gods/containers"
|
||||
|
||||
// Assert Iterator implementation
|
||||
var _ containers.ReverseIteratorWithIndex = (*Iterator)(nil)
|
||||
|
||||
// Iterator returns a stateful iterator whose values can be fetched by an index.
|
||||
type Iterator struct {
|
||||
queue *Queue
|
||||
index int
|
||||
}
|
||||
|
||||
// Iterator returns a stateful iterator whose values can be fetched by an index.
|
||||
func (queue *Queue) Iterator() Iterator {
|
||||
return Iterator{queue: queue, index: -1}
|
||||
}
|
||||
|
||||
// Next moves the iterator to the next element and returns true if there was a next element in the container.
|
||||
// If Next() returns true, then next element's index and value can be retrieved by Index() and Value().
|
||||
// If Next() was called for the first time, then it will point the iterator to the first element if it exists.
|
||||
// Modifies the state of the iterator.
|
||||
func (iterator *Iterator) Next() bool {
|
||||
if iterator.index < iterator.queue.Size() {
|
||||
iterator.index++
|
||||
}
|
||||
return iterator.queue.withinRange(iterator.index)
|
||||
}
|
||||
|
||||
// Prev moves the iterator to the previous element and returns true if there was a previous element in the container.
|
||||
// If Prev() returns true, then previous element's index and value can be retrieved by Index() and Value().
|
||||
// Modifies the state of the iterator.
|
||||
func (iterator *Iterator) Prev() bool {
|
||||
if iterator.index >= 0 {
|
||||
iterator.index--
|
||||
}
|
||||
return iterator.queue.withinRange(iterator.index)
|
||||
}
|
||||
|
||||
// Value returns the current element's value.
|
||||
// Does not modify the state of the iterator.
|
||||
func (iterator *Iterator) Value() interface{} {
|
||||
value, _ := iterator.queue.list.Get(iterator.index)
|
||||
return value
|
||||
}
|
||||
|
||||
// Index returns the current element's index.
|
||||
// Does not modify the state of the iterator.
|
||||
func (iterator *Iterator) Index() int {
|
||||
return iterator.index
|
||||
}
|
||||
|
||||
// Begin resets the iterator to its initial state (one-before-first)
|
||||
// Call Next() to fetch the first element if any.
|
||||
func (iterator *Iterator) Begin() {
|
||||
iterator.index = -1
|
||||
}
|
||||
|
||||
// End moves the iterator past the last element (one-past-the-end).
|
||||
// Call Prev() to fetch the last element if any.
|
||||
func (iterator *Iterator) End() {
|
||||
iterator.index = iterator.queue.Size()
|
||||
}
|
||||
|
||||
// First moves the iterator to the first element and returns true if there was a first element in the container.
|
||||
// If First() returns true, then first element's index and value can be retrieved by Index() and Value().
|
||||
// Modifies the state of the iterator.
|
||||
func (iterator *Iterator) First() bool {
|
||||
iterator.Begin()
|
||||
return iterator.Next()
|
||||
}
|
||||
|
||||
// Last moves the iterator to the last element and returns true if there was a last element in the container.
|
||||
// If Last() returns true, then last element's index and value can be retrieved by Index() and Value().
|
||||
// Modifies the state of the iterator.
|
||||
func (iterator *Iterator) Last() bool {
|
||||
iterator.End()
|
||||
return iterator.Prev()
|
||||
}
|
||||
|
||||
// NextTo moves the iterator to the next element from current position that satisfies the condition given by the
|
||||
// passed function, and returns true if there was a next element in the container.
|
||||
// If NextTo() returns true, then next element's index and value can be retrieved by Index() and Value().
|
||||
// Modifies the state of the iterator.
|
||||
func (iterator *Iterator) NextTo(f func(index int, value interface{}) bool) bool {
|
||||
for iterator.Next() {
|
||||
index, value := iterator.Index(), iterator.Value()
|
||||
if f(index, value) {
|
||||
return true
|
||||
}
|
||||
}
|
||||
return false
|
||||
}
|
||||
|
||||
// PrevTo moves the iterator to the previous element from current position that satisfies the condition given by the
|
||||
// passed function, and returns true if there was a next element in the container.
|
||||
// If PrevTo() returns true, then next element's index and value can be retrieved by Index() and Value().
|
||||
// Modifies the state of the iterator.
|
||||
func (iterator *Iterator) PrevTo(f func(index int, value interface{}) bool) bool {
|
||||
for iterator.Prev() {
|
||||
index, value := iterator.Index(), iterator.Value()
|
||||
if f(index, value) {
|
||||
return true
|
||||
}
|
||||
}
|
||||
return false
|
||||
}
|
||||
@@ -0,0 +1,33 @@
|
||||
// Copyright (c) 2015, Emir Pasic. All rights reserved.
|
||||
// Use of this source code is governed by a BSD-style
|
||||
// license that can be found in the LICENSE file.
|
||||
|
||||
package arrayqueue
|
||||
|
||||
import (
|
||||
"github.com/emirpasic/gods/containers"
|
||||
)
|
||||
|
||||
// Assert Serialization implementation
|
||||
var _ containers.JSONSerializer = (*Queue)(nil)
|
||||
var _ containers.JSONDeserializer = (*Queue)(nil)
|
||||
|
||||
// ToJSON outputs the JSON representation of the queue.
|
||||
func (queue *Queue) ToJSON() ([]byte, error) {
|
||||
return queue.list.ToJSON()
|
||||
}
|
||||
|
||||
// FromJSON populates the queue from the input JSON representation.
|
||||
func (queue *Queue) FromJSON(data []byte) error {
|
||||
return queue.list.FromJSON(data)
|
||||
}
|
||||
|
||||
// UnmarshalJSON @implements json.Unmarshaler
|
||||
func (queue *Queue) UnmarshalJSON(bytes []byte) error {
|
||||
return queue.FromJSON(bytes)
|
||||
}
|
||||
|
||||
// MarshalJSON @implements json.Marshaler
|
||||
func (queue *Queue) MarshalJSON() ([]byte, error) {
|
||||
return queue.ToJSON()
|
||||
}
|
||||
Reference in New Issue
Block a user