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/**
* ¶ÁÈ¡Îļþ×îºóÈô¸ÉÐеÄÊý¾Ý
*
* @param string $filename
* ÎļþÃû
* @param string $rows
* ÐÐÊý
* @param string $size
* Äڴ滺³åÇø´óС£¬Ä¬ÈÏΪ1024×Ö½Ú
* @param string $ending
* ÐÐβ·Ö¸ô·û£¬Ä¬ÈÏΪ\n
* @return array
* ¶ÁÈ¡³É¹¦Ôò·µ»Ø×Ö·û´®Êý×飬ÎļþβµÄ×Ö·û´®¿¿Ç°£¬¶Áȡʧ°ÜÔò·µ»Øfalse
*/
function tail($filename, $rows, $size = 1024, $ending = "\n") {
$ret = false;
if ($rows > 0 && $fp = fopen($filename, 'rb')) {
$pos = filesize($filename);
$ret = array();
flock($fp, LOCK_SH);

$data = '';
$found = 0;
while ($found < $rows) {
$pos = $pos - $size;
if ($pos < 0) {
$size = 1024 + $pos;
$pos = 0;
}
fseek($fp, $pos, SEEK_SET);
$data = fread($fp, $size) . $data;
$tmp = explode($ending, $data);
$count = count($tmp);
for ($i = 1; $i < $count; $i++) {
$ret[] = $tmp[$count - $i];
$found++;
if ($found >= $rows) {
break;
}
}
$data = $tmp[0];
if ($pos <= 0) {
break;
}
}
flock($fp, LOCK_UN);
fclose($fp);
}
return $ret;
}