php实现求相对时间函数

<?php
function relativeTime($time = false, $limit = 86400, $format = g:i A M jS) {
  if (empty($time) || (!is_string($time) & amp; & amp;
  !is_numeric($time))) $time = time();
  elseif (is_string($time)) $time = strtotime($time);
  $now = time();
  $relative = ;
  if ($time === $now) $relative = now;
  elseif ($time > $now) $relative = in the future;
  else {
    $diff = $now - $time;
    if ($diff >= $limit) $relative = date($format, $time);
    elseif ($diff < 60) {
      $relative = less than one minute ago;
    } elseif (($minutes = ceil($diff / 60)) < 60) {
      $relative = $minutes .  minute . (((int)$minutes === 1) ?  : s) .  ago;
    } else {
      $hours = ceil($diff / 3600);
      $relative = about  . $hours .  hour . (((int)$hours === 1) ?  : s) .  ago;
    }
  }
  return $relative;
}