Classes List

Symfony\Component\Form\Util\OrderedHashMap

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<?php

/* * This file is part of the Symfony package. * * (c) Fabien Potencier <fabien@symfony.com> * * For the full copyright and license information, please view the LICENSE * file that was distributed with this source code. */


namespace Symfony\Component\Form\Util;

/** * A hash map which keeps track of deletions and additions. * * Like in associative arrays, elements can be mapped to integer or string keys. * Unlike associative arrays, the map keeps track of the order in which keys * were added and removed. This order is reflected during iteration. * * The map supports concurrent modification during iteration. That means that * you can insert and remove elements from within a foreach loop and the * iterator will reflect those changes accordingly. * * While elements that are added during the loop are recognized by the iterator, * changed elements are not. Otherwise the loop could be infinite if each loop * changes the current element: * * $map = new OrderedHashMap(); * $map[1] = 1; * $map[2] = 2; * $map[3] = 3; * * foreach ($map as $index => $value) { * echo "$index: $value\n" * if (1 === $index) { * $map[1] = 4; * $map[] = 5; * } * } * * print_r(iterator_to_array($map)); * * // => 1: 1 * // 2: 2 * // 3: 3 * // 4: 5 * // Array * // ( * // [1] => 4 * // [2] => 2 * // [3] => 3 * // [4] => 5 * // ) * * The map also supports multiple parallel iterators. That means that you can * nest foreach loops without affecting each other's iteration: * * foreach ($map as $index => $value) { * foreach ($map as $index2 => $value2) { * // ... * } * } * * @author Bernhard Schussek <bschussek@gmail.com> */
class OrderedHashMap implements \ArrayAccess\IteratorAggregate\Countable
{
    /** * The elements of the map, indexed by their keys. * * @var array */
    private $elements = array();

    /** * The keys of the map in the order in which they were inserted or changed. * * @var array */
    private $orderedKeys = array();

    /** * References to the cursors of all open iterators. * * @var array */
    private $managedCursors = array();

    /** * Creates a new map. * * @param array $elements The elements to insert initially */
    public function __construct(array $elements = array())
    {
        $this->elements = $elements;
        $this->orderedKeys = array_keys($elements);
    }

    /** * {@inheritdoc} */
    public function offsetExists($key)
    {
        return isset($this->elements[$key]);
    }

    /** * {@inheritdoc} */
    public function offsetGet($key)
    {
        if (!isset($this->elements[$key])) {
            throw new \OutOfBoundsException('The offset "'.$key.'" does not exist.');
        }

        return $this->elements[$key];
    }

    /** * {@inheritdoc} */
    public function offsetSet($key$value)
    {
        if (null === $key || !isset($this->elements[$key])) {
            if (null === $key) {
                $key = array() === $this->orderedKeys
                    // If the array is empty, use 0 as key
                    ? 0
                    // Imitate PHP's behavior of generating a key that equals
                    // the highest existing integer key + 1
                    : 1 + (int) max($this->orderedKeys);
            }

            $this->orderedKeys[] = (string) $key;
        }

        $this->elements[$key] = $value;
    }

    /** * {@inheritdoc} */
    public function offsetUnset($key)
    {
        if (false !== ($position = array_search((string) $key$this->orderedKeys))) {
            array_splice($this->orderedKeys$position1);
            unset($this->elements[$key]);

            foreach ($this->managedCursors as $i => $cursor) {
                if ($cursor >= $position) {
                    --$this->managedCursors[$i];
                }
            }
        }
    }

    /** * {@inheritdoc} */
    public function getIterator()
    {
        return new OrderedHashMapIterator($this->elements$this->orderedKeys$this->managedCursors);
    }

    /** * {@inheritdoc} */
    public function count()
    {
        return count($this->elements);
    }
}