Round with Precision

gistfile1.php

<?php

    /**
     * Rounds a float with direction.
     *
     * Since round() doesn't support an optional rounding mode until 5.3 I
     * had to roll my own function to do so in the meantime.
     *
     * Note: Does not support negative precision.
     *
     * @static
     * @param  float $value the value to be rounded
     * @param  integer $precision optional decimal precision to round to
     * @param  string $mode optional direction to round to
     * @return float potentially rounded value
     */
    public static function round($value, $precision = 0, $mode = null)
    {
        if ($precision >= 0)
        {
            $offset = (int)str_pad('1', $precision + 1, '0');
            $value  = (string)($value * $offset);
        }

        switch ($mode)
        {
            case 'floor':
                $value = floor($value);
                break;

            case 'ceiling':
                $value = ceil($value);
                break;

            default:
                $value = round($value);
                break;
        }

        if ($precision >= 0)
        {
            $value = number_format($value / $offset, 2);
        }

        return $value;
    }

?>

line #22, if you don't cast the value as a string it becomes a float. once a float floor() may not handle as you'd except. case in point, 10.2:

var_dump(floor(10.2 * 100), floor(1020), floor((string)(10.2 * 100)));