php日期差 日期加减 DateDiff DateAdd

 
/**
 * 时间差
 * @param $part
 * @param $begin
 * @param $end
 */
function DateDiff($part, $begin, $end)
{
    $diff = $end - $begin;
    switch($part)
    {
        case "y": $retval = bcdiv($diff, (60 * 60 * 24 * 365)); break;
        case "m": $retval = bcdiv($diff, (60 * 60 * 24 * 30)); break;
        case "w": $retval = bcdiv($diff, (60 * 60 * 24 * 7)); break;
        case "d": $retval = bcdiv($diff, (60 * 60 * 24)); break;
        case "h": $retval = bcdiv($diff, (60 * 60)); break;
        case "n": $retval = bcdiv($diff, 60); break;
        case "s": $retval = $diff; break;
    }
    return $retval;
}
function DateAdd($part, $number, $date)
{
    $date_array = getdate($date);
    $hor = $date_array["hours"];
    $min = $date_array["minutes"];
    $sec = $date_array["seconds"];
    $mon = $date_array["mon"];
    $day = $date_array["mday"];
    $yar = $date_array["year"];
    switch($part)
    {
        case "y": $yar += $number; break;
        case "q": $mon += ($number * 3); break;
        case "m": $mon += $number; break;
        case "w": $day += ($number * 7); break;
        case "d": $day += $number; break;
        case "h": $hor += $number; break;
        case "n": $min += $number; break;
        case "s": $sec += $number; break;
    }
    return date("Y-m-d H:i:s", mktime($hor, $min, $sec, $mon, $day, $yar));
}