PHP not have a function for XML-safe entity decode? Not have some xml_entity_decode?

Question

THE PROBLEM: I need a XML file \"full encoded\" by UTF8; that is, with no entity representing symbols, all symbols enconded by UTF8, except the only 3 ones that are

Answer 1

    public function entity_decode($str, $charset = NULL)
{
    if (strpos($str, '&') === FALSE)
    {
        return $str;
    }

    static $_entities;

    isset($charset) OR $charset = $this->charset;
    $flag = is_php('5.4')
        ? ENT_COMPAT | ENT_HTML5
        : ENT_COMPAT;

    do
    {
        $str_compare = $str;

        // Decode standard entities, avoiding false positives
        if ($c = preg_match_all('/&[a-z]{2,}(?![a-z;])/i', $str, $matches))
        {
            if ( ! isset($_entities))
            {
                $_entities = array_map('strtolower', get_html_translation_table(HTML_ENTITIES, $flag, $charset));

                // If we're not on PHP 5.4+, add the possibly dangerous HTML 5
                // entities to the array manually
                if ($flag === ENT_COMPAT)
                {
                    $_entities[':'] = ':';
                    $_entities['('] = '(';
                    $_entities[')'] = '&rpar';
                    $_entities["\n"] = '&newline;';
                    $_entities["\t"] = '&tab;';
                }
            }

            $replace = array();
            $matches = array_unique(array_map('strtolower', $matches[0]));
            for ($i = 0; $i < $c; $i++)
            {
                if (($char = array_search($matches[$i].';', $_entities, TRUE)) !== FALSE)
                {
                    $replace[$matches[$i]] = $char;
                }
            }

            $str = str_ireplace(array_keys($replace), array_values($replace), $str);
        }

        // Decode numeric & UTF16 two byte entities
        $str = html_entity_decode(
            preg_replace('/(&#(?:x0*[0-9a-f]{2,5}(?![0-9a-f;]))|(?:0*\d{2,4}(?![0-9;])))/iS', '$1;', $str),
            $flag,
            $charset
        );
    }
    while ($str_compare !== $str);
    return $str;
}