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    <h3>Editing: TranslatorTrait.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\Contracts\Translation;

use Symfony\Component\Translation\Exception\InvalidArgumentException;

/**
 * A trait to help implement TranslatorInterface and LocaleAwareInterface.
 *
 * @author Fabien Potencier &lt;fabien@symfony.com&gt;
 */
trait TranslatorTrait
{
    private $locale;

    /**
     * {@inheritdoc}
     */
    public function setLocale(string $locale)
    {
        $this-&gt;locale = $locale;
    }

    /**
     * {@inheritdoc}
     *
     * @return string
     */
    public function getLocale()
    {
        return $this-&gt;locale ?: (class_exists(\Locale::class) ? \Locale::getDefault() : 'en');
    }

    /**
     * {@inheritdoc}
     */
    public function trans(?string $id, array $parameters = [], ?string $domain = null, ?string $locale = null): string
    {
        if (null === $id || '' === $id) {
            return '';
        }

        if (!isset($parameters['%count%']) || !is_numeric($parameters['%count%'])) {
            return strtr($id, $parameters);
        }

        $number = (float) $parameters['%count%'];
        $locale = $locale ?: $this-&gt;getLocale();

        $parts = [];
        if (preg_match('/^\|++$/', $id)) {
            $parts = explode('|', $id);
        } elseif (preg_match_all('/(?:\|\||[^\|])++/', $id, $matches)) {
            $parts = $matches[0];
        }

        $intervalRegexp = &lt;&lt;&lt;'EOF'
/^(?P&lt;interval&gt;
    ({\s*
        (\-?\d+(\.\d+)?[\s*,\s*\-?\d+(\.\d+)?]*)
    \s*})

        |

    (?P&lt;left_delimiter&gt;[\[\]])
        \s*
        (?P&lt;left&gt;-Inf|\-?\d+(\.\d+)?)
        \s*,\s*
        (?P&lt;right&gt;\+?Inf|\-?\d+(\.\d+)?)
        \s*
    (?P&lt;right_delimiter&gt;[\[\]])
)\s*(?P&lt;message&gt;.*?)$/xs
EOF;

        $standardRules = [];
        foreach ($parts as $part) {
            $part = trim(str_replace('||', '|', $part));

            // try to match an explicit rule, then fallback to the standard ones
            if (preg_match($intervalRegexp, $part, $matches)) {
                if ($matches[2]) {
                    foreach (explode(',', $matches[3]) as $n) {
                        if ($number == $n) {
                            return strtr($matches['message'], $parameters);
                        }
                    }
                } else {
                    $leftNumber = '-Inf' === $matches['left'] ? -\INF : (float) $matches['left'];
                    $rightNumber = is_numeric($matches['right']) ? (float) $matches['right'] : \INF;

                    if (('[' === $matches['left_delimiter'] ? $number &gt;= $leftNumber : $number &gt; $leftNumber)
                        &amp;&amp; (']' === $matches['right_delimiter'] ? $number &lt;= $rightNumber : $number &lt; $rightNumber)
                    ) {
                        return strtr($matches['message'], $parameters);
                    }
                }
            } elseif (preg_match('/^\w+\:\s*(.*?)$/', $part, $matches)) {
                $standardRules[] = $matches[1];
            } else {
                $standardRules[] = $part;
            }
        }

        $position = $this-&gt;getPluralizationRule($number, $locale);

        if (!isset($standardRules[$position])) {
            // when there's exactly one rule given, and that rule is a standard
            // rule, use this rule
            if (1 === \count($parts) &amp;&amp; isset($standardRules[0])) {
                return strtr($standardRules[0], $parameters);
            }

            $message = sprintf('Unable to choose a translation for &quot;%s&quot; with locale &quot;%s&quot; for value &quot;%d&quot;. Double check that this translation has the correct plural options (e.g. &quot;There is one apple|There are %%count%% apples&quot;).', $id, $locale, $number);

            if (class_exists(InvalidArgumentException::class)) {
                throw new InvalidArgumentException($message);
            }

            throw new \InvalidArgumentException($message);
        }

        return strtr($standardRules[$position], $parameters);
    }

    /**
     * Returns the plural position to use for the given locale and number.
     *
     * The plural rules are derived from code of the Zend Framework (2010-09-25),
     * which is subject to the new BSD license (http://framework.zend.com/license/new-bsd).
     * Copyright (c) 2005-2010 Zend Technologies USA Inc. (http://www.zend.com)
     */
    private function getPluralizationRule(float $number, string $locale): int
    {
        $number = abs($number);

        switch ('pt_BR' !== $locale &amp;&amp; 'en_US_POSIX' !== $locale &amp;&amp; \strlen($locale) &gt; 3 ? substr($locale, 0, strrpos($locale, '_')) : $locale) {
            case 'af':
            case 'bn':
            case 'bg':
            case 'ca':
            case 'da':
            case 'de':
            case 'el':
            case 'en':
            case 'en_US_POSIX':
            case 'eo':
            case 'es':
            case 'et':
            case 'eu':
            case 'fa':
            case 'fi':
            case 'fo':
            case 'fur':
            case 'fy':
            case 'gl':
            case 'gu':
            case 'ha':
            case 'he':
            case 'hu':
            case 'is':
            case 'it':
            case 'ku':
            case 'lb':
            case 'ml':
            case 'mn':
            case 'mr':
            case 'nah':
            case 'nb':
            case 'ne':
            case 'nl':
            case 'nn':
            case 'no':
            case 'oc':
            case 'om':
            case 'or':
            case 'pa':
            case 'pap':
            case 'ps':
            case 'pt':
            case 'so':
            case 'sq':
            case 'sv':
            case 'sw':
            case 'ta':
            case 'te':
            case 'tk':
            case 'ur':
            case 'zu':
                return (1 == $number) ? 0 : 1;

            case 'am':
            case 'bh':
            case 'fil':
            case 'fr':
            case 'gun':
            case 'hi':
            case 'hy':
            case 'ln':
            case 'mg':
            case 'nso':
            case 'pt_BR':
            case 'ti':
            case 'wa':
                return ($number &lt; 2) ? 0 : 1;

            case 'be':
            case 'bs':
            case 'hr':
            case 'ru':
            case 'sh':
            case 'sr':
            case 'uk':
                return ((1 == $number % 10) &amp;&amp; (11 != $number % 100)) ? 0 : ((($number % 10 &gt;= 2) &amp;&amp; ($number % 10 &lt;= 4) &amp;&amp; (($number % 100 &lt; 10) || ($number % 100 &gt;= 20))) ? 1 : 2);

            case 'cs':
            case 'sk':
                return (1 == $number) ? 0 : ((($number &gt;= 2) &amp;&amp; ($number &lt;= 4)) ? 1 : 2);

            case 'ga':
                return (1 == $number) ? 0 : ((2 == $number) ? 1 : 2);

            case 'lt':
                return ((1 == $number % 10) &amp;&amp; (11 != $number % 100)) ? 0 : ((($number % 10 &gt;= 2) &amp;&amp; (($number % 100 &lt; 10) || ($number % 100 &gt;= 20))) ? 1 : 2);

            case 'sl':
                return (1 == $number % 100) ? 0 : ((2 == $number % 100) ? 1 : (((3 == $number % 100) || (4 == $number % 100)) ? 2 : 3));

            case 'mk':
                return (1 == $number % 10) ? 0 : 1;

            case 'mt':
                return (1 == $number) ? 0 : (((0 == $number) || (($number % 100 &gt; 1) &amp;&amp; ($number % 100 &lt; 11))) ? 1 : ((($number % 100 &gt; 10) &amp;&amp; ($number % 100 &lt; 20)) ? 2 : 3));

            case 'lv':
                return (0 == $number) ? 0 : (((1 == $number % 10) &amp;&amp; (11 != $number % 100)) ? 1 : 2);

            case 'pl':
                return (1 == $number) ? 0 : ((($number % 10 &gt;= 2) &amp;&amp; ($number % 10 &lt;= 4) &amp;&amp; (($number % 100 &lt; 12) || ($number % 100 &gt; 14))) ? 1 : 2);

            case 'cy':
                return (1 == $number) ? 0 : ((2 == $number) ? 1 : (((8 == $number) || (11 == $number)) ? 2 : 3));

            case 'ro':
                return (1 == $number) ? 0 : (((0 == $number) || (($number % 100 &gt; 0) &amp;&amp; ($number % 100 &lt; 20))) ? 1 : 2);

            case 'ar':
                return (0 == $number) ? 0 : ((1 == $number) ? 1 : ((2 == $number) ? 2 : ((($number % 100 &gt;= 3) &amp;&amp; ($number % 100 &lt;= 10)) ? 3 : ((($number % 100 &gt;= 11) &amp;&amp; ($number % 100 &lt;= 99)) ? 4 : 5))));

            default:
                return 0;
        }
    }
}
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