这个类可以判断文件的大小，即使大于2gb，它可以使用不同的方法来确定一个大的文件。
<?php
require ("filesizeHelper.php");
$filesizeHelper = new FilesizeHelper();
$file = 'F:codepearl.text';
//$file ="/media/disk-1/Just.A.Very.Large.File.avi";
$filesize = $filesizeHelper->getFileSize($file);
echo"<pre>";
var_dump($filesize);<?php
/**
* ----------------------------------------------------------------------
* FileSizeHelper
* ----------------------------------------------------------------------
*
* Class for manipulating large files (bigger than 2GB)
*
* This class detects the real file size of a specified file even if the
* file size is begger than 2GB, the class also able to format the resulted
* file size in KB, MB, GB, TB units which make it more readable.
*
* The class uses several methods to detect bigger file sizes:
* 1. The native filesize() function
* 2. Using the cURL module
* 3. Using the php native seek function
* 4. Windows COM interface (on windows server)
* 5. Using external program (exec() function needed)
*/
class FilesizeHelper {
/**
* File path
*
* @var string
* @accessprivate
*/
private $path;
/**
* File size in bytes
*
* @var float
* @accessprivate
*/
private $byteSize;
/**
* Whether we are on Windows platform or another OS (*nix and MacOS)
*
* @var bool
* @accessprivate
*/
private $isWindows;
/**
* Constructor
*
* @accesspublic
* @param void
* @return void
*/
public function __construct() {
// Check if we are on Windows platform
$this->isWindows = (strtoupper(substr(PHP_OS, 0, 3)) == 'WIN');
}
/**
* Gets the size of the specified file
*
* @accesspublic
* @paramstringThe file path
* @paramboolWhether to format the file size in KB, MB, GB, TB
* @return mixed
*/
public function getFileSize($file, $formatted = true) {
// Set the path of the file
$this->path = $file;
// Check for a valid file path
$this->__checkFilePath();
// Get the file size in bytes
$this->byteSize = (float) $this->__getByteSize();
// If failed to get the file size or the file size is zero, return a blank result
if (!$this->byteSize) {
if (!$formatted) {
return 0;
}
// Return a blank array
$blank_size = $this->__formatFileSize();
return array(0, $blank_size[0], $blank_size[1]);
}
// Return the bytesize if no formatting is needed
if (!$formatted) {
return $this->byteSize;
}
// Return an array containing the file size information
return $this->__formatFileSize();
}
/**
* Formats the file size in KB, MB, GB, TB units
*
* @accessprivate
* @param void
* @return arrayReturn arry containing the file size information
*/
private function __formatFileSize() {
// If the file size is zero return a blank result
$_size = $this->byteSize;
if (!$_size || $_size < 0) {
return array(0, '0 B', array(0, 'B'));
}
// If the file size is smaller than 1KB
if ($_size <= 1024) {
return array(0, '1 KB', array(1, 'KB'));
}
// Set an array of all file size units
$size_units = Array('B', 'KB', 'MB', 'GB', 'TB', 'PB', 'EB');
// Set the initial unit to Bytes
$unit = $size_units[0];
// Loop through all file size units
for ($i = 1; ($i < count($size_units) && $_size >= 1024); $i++) {
$_size = $_size / 1024;
$unit = $size_units[$i];
}
// Set the number of digits after the decimal place in the resulted file size
$round = 2;
// If the file size is in KiloByte we do not need any decimal numbers
if ($unit == 'KB') {
$round = 0;
}
// Round the file size
$formatted = round((float) $_size, $round);
// Return the file size data
return array($this->byteSize, $formatted ."". $unit, array($formatted, $unit));
}
/**
* Chek if the file is exist
*
* @accessprivate
* @param void
* @return void
*/
private function __checkFilePath() {
clearstatcache();
if (!file_exists($this->path)) {
throw new Exception("File not found at $this->path");
}
}
/**
* Gets the size of the specified file in bytes
*
* @accessprivate
* @param void
* @return stringThe file size in bytes
*/
private function __getByteSize() {
// Try the php native filesize() function.
$bytesize = @filesize($this->path);
if (false !== $bytesize && $bytesize >= 0) {
return $bytesize;
}
// If filesize() fails with larger files, try to get the size using curl module.
$bytesize = $this->__useCurl();
if ($bytesize) {
return $bytesize;
}
// If curl fails to get the file size try using the php native seek function.
$bytesize = $this->__useNativeSeek();
if ($bytesize) {
return $bytesize;
}
// If the native seek fails to get the file size and we are on windows try using Windows COM interface
$bytesize = $this->__useCom();
if ($bytesize) {
return $bytesize;
}
// If all the above methods failed to get the file size try using external program (exec() function needed)
$bytesize = $this->__useExec();
if ($bytesize) {
return $bytesize;
}
// Unable to get the file size in bytes
throw new Exception("Unable to get the file size for the file". $this->path ."!");
}
/**
* Gets the file size using curl module
*
* @accessprivate
* @param void
* @returnmixedThe file size as string or false when fail or cUrl module not available
* @seehttp://www.php.net/manual/en/function.filesize.php#100434
*/
private function __useCurl() {
// If the curl module is not available return false
if (!function_exists("curl_init")) {
return false;
}
$ch = curl_init("file://". $this->path);
curl_setopt($ch, CURLOPT_NOBODY, true);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_HEADER, true);
$data = curl_exec($ch);
curl_close($ch);
if ($data !== false && preg_match('/Content-Length: (d+)/', $data, $matches)) {
return (string) $matches[1];
}
}
/**
* Gets the file size by using native fseek function
*
* @accessprivate
* @param void
* @returnmixedThe file size as string or false when fail
* @seehttp://www.php.net/manual/en/function.filesize.php#79023
* @seehttp://www.php.net/manual/en/function.filesize.php#102135
*/
private function __useNativeSeek() {
// This should work for large files on 64bit platforms and for small files every where
$fp = @fopen($this->path,"rb");
// If failed to open the file return false
if (!$fp) {
return false;
}
flock($fp, LOCK_SH);
// Seeks past the end-of-file
$res = fseek($fp, 0, SEEK_END);
if ($res === 0) {
// Get the current position of the file pointer
$pos = ftell($fp);
flock($fp, LOCK_UN);
fclose($fp);
// $pos will be positive int if file is <2GB
// if is >2GB <4GB it will be negative number
if ($pos >= 0) {
return (string) $pos;
}
else {
return sprintf("%u", $pos);
}
}
else {
flock($fp, LOCK_UN);
fclose($fp);
return false;
}
}
/**
* Gets the file size by using Windows COM interface
*
* @accessprivate
* @param void
* @returnmixedThe file size as string or false when fail or COM not available
*/
private function __useCom() {
if (!$this->isWindows || !class_exists("COM")) {
return false;
}
// Use the Windows COM interface
$fsobj = new COM('Scripting.FileSystemObject');
if (dirname($this->path) == '.') {
$this->path = ((substr(getcwd(), -1) == DIRECTORY_SEPARATOR) ? getcwd() . basename($this->path) : getcwd() . DIRECTORY_SEPARATOR . basename($this->path));
}
// Get the file data
$f = $fsobj->GetFile($this->path);
// Convert to string
return (string) $f->Size;
}
/**
* Gets the file size by using external program (exec needed)
*
* @accessprivate
* @param void
* @return mixedThe file size as string or false when fail or or exec is disabled
*/
private function __useExec() {
// If exeec is disable return false
if (!function_exists("exec")) {
return false;
}
//Escape the file path string to be used as a shell argument
$escapedPath = escapeshellarg($this->path);
// If we are on Windows
if ($this->isWindows) {
// Try using the NT substition modifier %~z
$size = trim(exec("for %F in ($escapedPath) do @echo %~zF"));
}
// If other OS (*nix and MacOS)
else {
// If the platform is not Windows, use the stat command (should work for *nix and MacOS)
$size = trim(exec("stat -c%s $escapedPath"));
}
// If the return is not blank, not zero, and is number
if ($size && ctype_digit($size)) {
return (string) $size;
}
// An error has occured
return false;
}
} 
