$def->addElement('video', 'Block', 'Optional: (source, Flow) | (Flow, source) | Flow', 'Common', array(
                        'src' => 'URI',
                        'type' => 'Text',
                        'width' => 'Length',
                        'height' => 'Length',
                        'poster' => 'URI',
                        'preload' => 'Enum#auto,metadata,none',
                        'controls' => 'Bool',
                    ));
                    $def->addElement('source', 'Block', 'Flow', 'Common', array(
                        'src' => 'URI',
                        'type' => 'Text',
                    ));
                    if ($allow_style) {
                        $def->addElement('style', 'Block', 'Flow', 'Common', array('type' => 'Text'));
                    }
                }

                $purifier = new HTMLPurifier($config);
            }
            if (_PS_MAGIC_QUOTES_GPC_) {
                $html = stripslashes($html);
            }

            $html = $purifier->purify($html);

            if (_PS_MAGIC_QUOTES_GPC_) {
                $html = addslashes($html);
            }
        }

        return $html;
    }

    /**
     * Check if a constant was already defined
     * @param string $constant Constant name
     * @param mixed $value Default value to set if not defined
    */
    public static function safeDefine($constant, $value)
    {
        if (!defined($constant)) {
            define($constant, $value);
        }
    }

    /**
     * Spread an amount on lines, adjusting the $column field,
     * with the biggest adjustments going to the rows having the
     * highest $sort_column.
     *
     * E.g.:
     *
     * $rows = [['a' => 5.1], ['a' => 8.2]];
     *
     * spreadAmount(0.3, 1, $rows, 'a');
     *
     * => $rows is [['a' => 8.4], ['a' => 5.2]]
     *
     * @param $amount float  The amount to spread across the rows
     * @param $precision int Rounding precision
     *                       e.g. if $amount is 1, $precision is 0 and $rows = [['a' => 2], ['a' => 1]]
     *                       then the resulting $rows will be [['a' => 3], ['a' => 1]]
     *                       But if $precision were 1, then the resulting $rows would be [['a' => 2.5], ['a' => 1.5]]
     * @param &$rows array   An array, associative or not, containing arrays that have at least $column and $sort_column fields
     * @param $column string The column on which to perform adjustments
     */
    public static function spreadAmount($amount, $precision, &$rows, $column)
    {
        if (!is_array($rows) || empty($rows)) {
            return;
        }

        $sort_function = create_function('$a, $b', "return \$b['$column'] > \$a['$column'] ? 1 : -1;");

        uasort($rows, $sort_function);

        $unit = pow(10, $precision);

        $int_amount = (int)round($unit * $amount);

        $remainder = $int_amount % count($rows);
        $amount_to_spread = ($int_amount - $remainder) / count($rows) / $unit;

        $sign = ($amount >= 0 ? 1 : -1);
        $position = 0;
        foreach ($rows as &$row) {
            $adjustment_factor = $amount_to_spread;

            if ($position < abs($remainder)) {
                $adjustment_factor += $sign * 1 / $unit;
            }

            $row[$column] += $adjustment_factor;

            ++$position;
        }
        unset($row);
    }

    /**
     * Replaces elements from passed arrays into the first array recursively
     * @param array $base The array in which elements are replaced.
     * @param array $replacements The array from which elements will be extracted.
    */
    public static function arrayReplaceRecursive($base, $replacements)
    {
        if (function_exists('array_replace_recursive')) {
            return array_replace_recursive($base, $replacements);
        }

        foreach (array_slice(func_get_args(), 1) as $replacements) {
            $bref_stack = array(&$base);
            $head_stack = array($replacements);

            do {
                end($bref_stack);

                $bref = &$bref_stack[key($bref_stack)];
                $head = array_pop($head_stack);
                unset($bref_stack[key($bref_stack)]);
                foreach (array_keys($head) as $key) {
                    if (isset($key, $bref) && is_array($bref[$key]) && is_array($head[$key])) {
                        $bref_stack[] = &$bref[$key];
                        $head_stack[] = $head[$key];
                    } else {
                        $bref[$key] = $head[$key];
                    }
                }
            } while (count($head_stack));
        }
        return $base;
    }
}

/**
 * Compare 2 prices to sort products
 *
 * @param float $a
 * @param float $b
 * @return int
 */
/* Externalized because of a bug in PHP 5.1.6 when inside an object */
function cmpPriceAsc($a, $b)
{
    if ((float)$a['price_tmp'] < (float)$b['price_tmp']) {
        return (-1);
    } elseif ((float)$a['price_tmp'] > (float)$b['price_tmp']) {
        return (1);
    }
    return 0;
}

function cmpPriceDesc($a, $b)
{
    if ((float)$a['price_tmp'] < (float)$b['price_tmp']) {
        return 1;
    } elseif ((float)$a['price_tmp'] > (float)$b['price_tmp']) {
        return -1;
    }
    return 0;
}