html_entity.php

См. документацию.

<?php
 
class CSecurityHtmlEntity
{
    private static $htmlMnemonics = array(
        "html" => array(
                "/&colon;/i", "/&tab;/i", "/&newline;/i"
            ),
        "text" => array(
                ":",           "\r",       "\n"
            ),
        );

    protected static function decodeCb($entity)
    {
        $ad = $entity[2];
        if($ad == ';')
            $ad="";
        $num = intval($entity[1]);
        return chr($num).$ad;
    }

    protected static function decodeCbHex($entity)
    {
        $ad = $entity[2];
        if($ad==';')
            $ad="";
        $num = intval(hexdec($entity[1]));
        return chr($num).$ad;
    }

    protected static function decode($string)
    {
        $string = preg_replace_callback("/\&\#(\d+)([^\d]|$)/is", array(__CLASS__, "decodeCb"), $string);
        $string = preg_replace_callback("/\&\#x([\da-f]+)([^\da-f]|$)/is", array(__CLASS__, "decodeCbHex"), $string);
        $string = preg_replace(self::$htmlMnemonics["html"], self::$htmlMnemonics["text"],$string);
        return $string;
    }

    public static function decodeString($pString)
    {
        $strY = $pString;
        $str1 = "";
        while($str1 <> $strY)
        {
            $str1 = $strY;
            $strY = self::decode($strY);
            $strY = str_replace("\x00", "", $strY);
            $strY = preg_replace("/\&\#0+(;|([^\d;]))/is", "\\2", $strY);
            $strY = preg_replace("/\&\#x0+(;|([^\da-f;]))/is", "\\2", $strY);
        }
 
        return $str1;
    }
}