PHP 5.4.37 Released

La classe SplQueue

(PHP 5 >= 5.3.0)

Introduction

La classe SplQueue fournit l'interface d'implémentation d'une queue, basée sur une liste doublement chaînée.

Synopsis de la classe

SplQueue extends SplDoublyLinkedList implements Iterator , ArrayAccess , Countable {
/* Méthodes */
__construct ( void )
mixed dequeue ( void )
void enqueue ( mixed $value )
void setIteratorMode ( int $mode )
/* Méthodes héritées */
public void SplDoublyLinkedList::add ( mixed $index , mixed $newval )
public mixed SplDoublyLinkedList::bottom ( void )
public int SplDoublyLinkedList::count ( void )
public mixed SplDoublyLinkedList::current ( void )
public bool SplDoublyLinkedList::isEmpty ( void )
public mixed SplDoublyLinkedList::key ( void )
public void SplDoublyLinkedList::next ( void )
public mixed SplDoublyLinkedList::offsetGet ( mixed $index )
public void SplDoublyLinkedList::offsetSet ( mixed $index , mixed $newval )
public void SplDoublyLinkedList::offsetUnset ( mixed $index )
public mixed SplDoublyLinkedList::pop ( void )
public void SplDoublyLinkedList::prev ( void )
public void SplDoublyLinkedList::push ( mixed $value )
public void SplDoublyLinkedList::rewind ( void )
public string SplDoublyLinkedList::serialize ( void )
public void SplDoublyLinkedList::setIteratorMode ( int $mode )
public mixed SplDoublyLinkedList::shift ( void )
public mixed SplDoublyLinkedList::top ( void )
public void SplDoublyLinkedList::unserialize ( string $serialized )
public void SplDoublyLinkedList::unshift ( mixed $value )
public bool SplDoublyLinkedList::valid ( void )
}

Sommaire

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User Contributed Notes 2 notes

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11
Manu Manjunath
11 months ago
SplQueue inherits from SplDoublyLinkedList. So, objects of SplQueue support methods push() and pop(). But please be advised that if you use push() and pop() methods on a SplQueue object, it behaves like a stack rather than a queue.

For example:

$q = new SplQueue();
$q->push(1);
$q->push(2);
$q->push(3);
$q->pop();
print_r($q);

Above code returns:

SplQueue Object
(
    [flags:SplDoublyLinkedList:private] => 4
    [dllist:SplDoublyLinkedList:private] => Array
        (
            [0] => 1
            [1] => 2
        )
)

Note that 3 got popped and *not* 1.

So, please make sure that you use only enqueue() and dequeue() methods on a SplQueue object and *not* push() and pop().
up
0
MrStonedOne
24 days ago
You can use shift/unshift and push/pop to dequeue/undequeue and queue/unqueue respectively. Really handy for those applications that use sockets where you might not know you can't send data until you attempt to.

for example, this is a function for an application that will un-dequeue the remainder of the data if socket_write indicated it did not write the entire contents of the provided data.

<?php
function processSendQueue($socket, $sendQueue) {
    while (!
$sendQueue->isEmpty()) {
                           
//shift() is the same as dequeue()
       
$senditem = $sendQueue->shift();

       
//returns the number of bytes written.
       
$rtn = socket_write($socket, $senditem);
        if (
$rtn === false) {
           
$sendQueue->unshift($senditem);
            throw new
exception("send error: " . socket_last_error($socket));
            return;
        }
        if (
$rtn < strlen($senditem) {
           
$sendQueue->unshift(substr($senditem, $rtn);
            break;
        }
    }
}
?>
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