/**
 * 带单位的文件大小字符串转换成字节数
 *
 * @param 
 * @arrange (512.笔记) jb51.cc
 **/
function StringSizeToBytes($Size){
 
    $Unit = strtolower($Size);
    $Unit = preg_replace('/[^a-z]/','',$Unit);
 
    $Value = intval(preg_replace('/[^0-9]/',$Size));
 
    $Units = array('b'=>0,'kb'=>1,'mb'=>2,'gb'=>3,'tb'=>4);
    $Exponent = isset($Units[$Unit]) ? $Units[$Unit] : 0;
 
    return ($Value * pow(1024,$Exponent));            
}

// Example usage:
// Check if a file is bigger than 10 MB
 
if (filesize('example.zip') > StringSizeToBytes('10 MB')){
    print 'File is to big !';
}
else {
    print 'File is okay';
}


/***   来自编程之家 jb51.cc（jb51.cc）   ***/