PHP將時間格式化幾天前、幾分鐘前等

<?php

class DateFormat
{
    private static $_DIFF_FORMAT = array(
        'DAY'           => '%s天前',
        'DAY_HOUR'      => '%s天%s小時前',
        'HOUR'          => '%s小時',
        'HOUR_MINUTE'   => '%s小時%s分前',
        'MINUTE'        => '%s分鐘前',
        'MINUTE_SECOND' => '%s分鐘%s秒前',
        'SECOND'        => '%s秒前',
    );

/**
 * 友好格式化時間
 * 
 * @param int 時間
 * @param array $formats
 * @return string
 */
public static function diff($timestamp, $formats = null) 
{
    if ($formats == null) {
        $formats = self::$_DIFF_FORMAT;
    }
    /* 計算出時間差 */
    $seconds = time() - $timestamp;
    $minutes = floor($seconds / 60);
    $hours   = floor($minutes / 60);
    $days    = floor($hours / 24);

    if ($days > 0) {
        $diffFormat = 'DAY';
    } else {
        $diffFormat = ($hours > 0) ? 'HOUR' : 'MINUTE';
        if ($diffFormat == 'HOUR') {
            $diffFormat .= ($minutes > 0 && ($minutes - $hours * 60) > 0) ? '_MINUTE' : '';
        } else {
            $diffFormat = (($seconds - $minutes * 60) > 0 && $minutes > 0) 
                            ? $diffFormat.'_SECOND' : 'SECOND';
        }
    }

    $dateDiff = null;
    switch ($diffFormat) {
        case 'DAY':
            $dateDiff = sprintf($formats[$diffFormat], $days);
            break;
        case 'DAY_HOUR':
            $dateDiff = sprintf($formats[$diffFormat], $days, $hours - $days * 60);
            break;
        case 'HOUR':
            $dateDiff = sprintf($formats[$diffFormat], $hours);
            break;
        case 'HOUR_MINUTE':
            $dateDiff = sprintf($formats[$diffFormat], $hours, $minutes - $hours * 60);
            break;
        case 'MINUTE':
            $dateDiff = sprintf($formats[$diffFormat], $minutes);
            break;
        case 'MINUTE_SECOND':
            $dateDiff = sprintf($formats[$diffFormat], $minutes, $seconds - $minutes * 60);
            break;
        case 'SECOND':
            $dateDiff = sprintf($formats[$diffFormat], $seconds);
            break;
    }
    return $dateDiff;
}

}
echo DateFormat::diff('1310455823');
/ 33分鐘47秒前  /</pre>