php读取大文件示例分享(文件操作类)

Lib_File2.php
代码如下:
<?php
 class Lib_File2
 {
  //文件目录
  private $root = '/data/wwwroot/kkpromo/data/';

  //文件后缀
  private $suffix = '.log';

  //文件句柄
  private $handle=null;

  //一次读取文件的最大记录数
  private $limit=40000;

  //每行读取的字节长度
  private $length=1024;

  //开始时间
  private  $startTime=0;

  //内存使用基准点
  private static $startMemory=0;

  //
  private $conn=null;

  //
  private static  $init=null;

  public static function instance()
  {
   self::$startMemory = memory_get_usage(true);

   if(self::$init && is_object(self::$init))
   {
    return self::$init;
   }

   self::$init = new self();

   return self::$init;
  }

  private function __construct(){}

  public  function setRoot($root)  
  {
   if(!is_dir($root)) die($root.' ROOT DOES NOT EXIST');
   $this->root = $root;
  }

  public function setSuffix($suffix)
  {
   $this->suffix = $suffix;
  }

  public function setLimit($limit)
  {
   if(!is_numeric($limit)) die($limit.' SHOULD BE NUMBERIC');
   if(intval($limit) > 1000000) die($limit.' SHOULD BE LOWER THAN 1000000');
   $this->limit = intval($limit);
  }

  public function _getFile($date , $appid , $op)
  {
   $filename = rtrim($this->root , '/').DIRECTORY_SEPARATOR.$date.DIRECTORY_SEPARATOR.$appid.'.'.$op.$this->suffix;
   if(!file_exists($filename))
   {
    die($filename.' FILE DOES NOT EXISTS!');
   }

   if(!is_file($filename))
   {
    die($filename.' FILE DOES NOT EXIST!');
   }

   if(!is_readable($filename))
   {
    die($filename.'  FILE ACCESS DENY!');
   }

   return $filename;
  }

  
  public function closeFile($date=null , $appid=null , $op=null)
  {
   if($op && $date && $appid)
   {
    if(is_object($this->handle[$date.'_'.$appid.'_'.$op]) || $this->conn[$date.'_'.$appid.'_'.$op])
    {
     unset($this->handle[$date.'_'.$appid.'_'.$op]);