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    <h3>Editing: AcceptHeader.php</h3>
    <textarea name="content" rows="20" cols="80">&lt;?php

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

namespace Symfony\Component\HttpFoundation;

// Help opcache.preload discover always-needed symbols
class_exists(AcceptHeaderItem::class);

/**
 * Represents an Accept-* header.
 *
 * An accept header is compound with a list of items,
 * sorted by descending quality.
 *
 * @author Jean-François Simon &lt;contact@jfsimon.fr&gt;
 */
class AcceptHeader
{
    /**
     * @var AcceptHeaderItem[]
     */
    private array $items = [];

    private bool $sorted = true;

    /**
     * @param AcceptHeaderItem[] $items
     */
    public function __construct(array $items)
    {
        foreach ($items as $item) {
            $this-&gt;add($item);
        }
    }

    /**
     * Builds an AcceptHeader instance from a string.
     */
    public static function fromString(?string $headerValue): self
    {
        $index = 0;

        $parts = HeaderUtils::split($headerValue ?? '', ',;=');

        return new self(array_map(function ($subParts) use (&amp;$index) {
            $part = array_shift($subParts);
            $attributes = HeaderUtils::combine($subParts);

            $item = new AcceptHeaderItem($part[0], $attributes);
            $item-&gt;setIndex($index++);

            return $item;
        }, $parts));
    }

    /**
     * Returns header value's string representation.
     */
    public function __toString(): string
    {
        return implode(',', $this-&gt;items);
    }

    /**
     * Tests if header has given value.
     */
    public function has(string $value): bool
    {
        return isset($this-&gt;items[$value]);
    }

    /**
     * Returns given value's item, if exists.
     */
    public function get(string $value): ?AcceptHeaderItem
    {
        return $this-&gt;items[$value] ?? $this-&gt;items[explode('/', $value)[0].'/*'] ?? $this-&gt;items['*/*'] ?? $this-&gt;items['*'] ?? null;
    }

    /**
     * Adds an item.
     *
     * @return $this
     */
    public function add(AcceptHeaderItem $item): static
    {
        $this-&gt;items[$item-&gt;getValue()] = $item;
        $this-&gt;sorted = false;

        return $this;
    }

    /**
     * Returns all items.
     *
     * @return AcceptHeaderItem[]
     */
    public function all(): array
    {
        $this-&gt;sort();

        return $this-&gt;items;
    }

    /**
     * Filters items on their value using given regex.
     */
    public function filter(string $pattern): self
    {
        return new self(array_filter($this-&gt;items, function (AcceptHeaderItem $item) use ($pattern) {
            return preg_match($pattern, $item-&gt;getValue());
        }));
    }

    /**
     * Returns first item.
     */
    public function first(): ?AcceptHeaderItem
    {
        $this-&gt;sort();

        return $this-&gt;items ? reset($this-&gt;items) : null;
    }

    /**
     * Sorts items by descending quality.
     */
    private function sort(): void
    {
        if (!$this-&gt;sorted) {
            uasort($this-&gt;items, function (AcceptHeaderItem $a, AcceptHeaderItem $b) {
                $qA = $a-&gt;getQuality();
                $qB = $b-&gt;getQuality();

                if ($qA === $qB) {
                    return $a-&gt;getIndex() &gt; $b-&gt;getIndex() ? 1 : -1;
                }

                return $qA &gt; $qB ? -1 : 1;
            });

            $this-&gt;sorted = true;
        }
    }
}
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