function encryptDecrypt($key, $string, $decrypt){ 
  if($decrypt){ 
    $decrypted = rtrim(mcrypt_decrypt(MCRYPT_RIJNDAEL_256, md5($key), base64_decode($string), MCRYPT_MODE_CBC, md5(md5($key))), "12"); 
    return $decrypted; 
  }else{ 
    $encrypted = base64_encode(mcrypt_encrypt(MCRYPT_RIJNDAEL_256, md5($key), $string, MCRYPT_MODE_CBC, md5(md5($key)))); 
    return $encrypted; 
  } 
}

function generateRandomString($length = 10) { 
  $characters = '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ'; 
  $randomString = ''; 
  for ($i = 0; $i < $length; $i++) { 
    $randomString .= $characters[rand(0, strlen($characters) - 1)]; 
  } 
  return $randomString; 
}

function getExtension($filename){ 
 $myext = substr($filename, strrpos($filename, '.')); 
 return str_replace('.','',$myext); 
}

$filename = '我的文档.doc'; 
echo getExtension($filename);

function formatSize($size) { 
  $sizes = array(" Bytes", " KB", " MB", " GB", " TB", " PB", " EB", " ZB", " YB"); 
  if ($size == 0) { 
    return('n/a'); 
  } else { 
   return (round($size/pow(1024, ($i = floor(log($size, 1024)))), 2) . $sizes[$i]); 
  } 
}

$thefile = filesize('test_file.mp3'); 
echo formatSize($thefile);

function stringParser($string,$replacer){ 
  $result = str_replace(array_keys($replacer), array_values($replacer),$string); 
  return $result; 
}

$string = 'The {b}anchor text{/b} is the {b}actual word{/b} or words used {br}to describe the link {br}itself'; 
$replace_array = array('{b}' => '<b>','{/b}' => '</b>','{br}' => '<br />'); 
echo stringParser($string,$replace_array);

function listDirFiles($DirPath){ 
  if($dir = opendir($DirPath)){ 
     while(($file = readdir($dir))!== false){ 
        if(!is_dir($DirPath.$file)) 
        { 
          echo "filename: $file<br />"; 
        } 
     } 
  } 
}

listDirFiles('home/some_folder/');

function curPageURL() { 
  $pageURL = 'http'; 
  if (!empty($_SERVER['HTTPS'])) {$pageURL .= "s";} 
  $pageURL .= "://"; 
  if ($_SERVER["SERVER_PORT"] != "80") { 
    $pageURL .= $_SERVER["SERVER_NAME"].":".$_SERVER["SERVER_PORT"].$_SERVER["REQUEST_URI"]; 
  } else { 
    $pageURL .= $_SERVER["SERVER_NAME"].$_SERVER["REQUEST_URI"]; 
  } 
  return $pageURL; 
}

echo curPageURL();

function download($filename){ 
  if ((isset($filename))&&(file_exists($filename))){ 
    header("Content-length: ".filesize($filename)); 
    header('Content-Type: application/octet-stream'); 
    header('Content-Disposition: attachment; filename="' . $filename . '"'); 
    readfile("$filename"); 
  } else { 
    echo "Looks like file does not exist!"; 
  } 
}

download('/down/test_45f73e852.zip');

/* 
 Utf-8、gb2312都支持的汉字截取函数 
 cut_str(字符串, 截取长度, 开始长度, 编码); 
 编码默认为 utf-8 
 开始长度默认为 0 
*/ 
function cutStr($string, $sublen, $start = 0, $code = 'UTF-8'){ 
  if($code == 'UTF-8'){ 
    $pa = "/[\x01-\x7f]|[\xc2-\xdf][\x80-\xbf]|\xe0[\xa0-\xbf][\x80-\xbf]|[\xe1-\xef][\x80-\xbf][\x80-\xbf]|\xf0[\x90-\xbf][\x80-\xbf][\x80-\xbf]|[\xf1-\xf7][\x80-\xbf][\x80-\xbf][\x80-\xbf]/"; 
    preg_match_all($pa, $string, $t_string); 

    if(count($t_string[0]) - $start > $sublen) return join('', array_slice($t_string[0], $start, $sublen))."..."; 
    return join('', array_slice($t_string[0], $start, $sublen)); 
  }else{ 
    $start = $start*2; 
    $sublen = $sublen*2; 
    $strlen = strlen($string); 
    $tmpstr = ''; 

    for($i=0; $i<$strlen; $i++){ 
      if($i>=$start && $i<($start+$sublen)){ 
        if(ord(substr($string, $i, 1))>129){ 
          $tmpstr.= substr($string, $i, 2); 
        }else{ 
          $tmpstr.= substr($string, $i, 1); 
        } 
      } 
      if(ord(substr($string, $i, 1))>129) $i++; 
    } 
    if(strlen($tmpstr)<$strlen ) $tmpstr.= "..."; 
    return $tmpstr; 
  } 
}

$str = "jQuery插件实现的加载图片和页面效果"; 
echo cutStr($str,16);

//获取用户真实IP 
function getIp() { 
  if (getenv("HTTP_CLIENT_IP") && strcasecmp(getenv("HTTP_CLIENT_IP"), "unknown")) 
    $ip = getenv("HTTP_CLIENT_IP"); 
  else 
    if (getenv("HTTP_X_FORWARDED_FOR") && strcasecmp(getenv("HTTP_X_FORWARDED_FOR"), "unknown")) 
      $ip = getenv("HTTP_X_FORWARDED_FOR"); 
    else 
      if (getenv("REMOTE_ADDR") && strcasecmp(getenv("REMOTE_ADDR"), "unknown")) 
        $ip = getenv("REMOTE_ADDR"); 
      else 
        if (isset ($_SERVER['REMOTE_ADDR']) && $_SERVER['REMOTE_ADDR'] && strcasecmp($_SERVER['REMOTE_ADDR'], "unknown")) 
          $ip = $_SERVER['REMOTE_ADDR']; 
        else 
          $ip = "unknown"; 
  return ($ip); 
}

echo getIp();

function injCheck($sql_str) { 
  $check = preg_match('/select|insert|update|delete|\'|\/\*|\*|\.\.\/|\.\/|union|into|load_file|outfile/', $sql_str); 
  if ($check) { 
    echo '非法字符！！'; 
    exit; 
  } else { 
    return $sql_str; 
  } 
}

echo injCheck('1 or 1=1');

function message($msgTitle,$message,$jumpUrl){ 
  $str = '<!DOCTYPE HTML>'; 
  $str .= '<html>'; 
  $str .= '<head>'; 
  $str .= '<meta charset="utf-8">'; 
  $str .= '<title>页面提示</title>'; 
  $str .= '<style type="text/css">'; 
  $str .= '*{margin:0; padding:0}a{color:#369; text-decoration:none;}a:hover{text-decoration:underline}body{height:100%; font:12px/18px Tahoma, Arial, sans-serif; color:#424242; background:#fff}.message{width:450px; height:120px; margin:16% auto; border:1px solid #99b1c4; background:#ecf7fb}.message h3{height:28px; line-height:28px; background:#2c91c6; text-align:center; color:#fff; font-size:14px}.msg_txt{padding:10px; margin-top:8px}.msg_txt h4{line-height:26px; font-size:14px}.msg_txt h4.red{color:#f30}.msg_txt p{line-height:22px}'; 
  $str .= '</style>'; 
  $str .= '</head>'; 
  $str .= '<body>'; 
  $str .= '<div>'; 
  $str .= '<h3>'.$msgTitle.'</h3>'; 
  $str .= '<div>'; 
  $str .= '<h4>'.$message.'</h4>'; 
  $str .= '<p>系统将在 <span style="color:blue;font-weight:bold">3</span> 秒后自动跳转,如果不想等待,直接点击 <a href="{$jumpUrl}">这里</a> 跳转</p>'; 
  $str .= "<script>setTimeout('location.replace(\'".$jumpUrl."\')',2000)</script>"; 
  $str .= '</div>'; 
  $str .= '</div>'; 
  $str .= '</body>'; 
  $str .= '</html>'; 
  echo $str; 
}

function changeTimeType($seconds) { 
  if ($seconds > 3600) { 
    $hours = intval($seconds / 3600); 
    $minutes = $seconds % 3600; 
    $time = $hours . ":" . gmstrftime('%M:%S', $minutes); 
  } else { 
    $time = gmstrftime('%H:%M:%S', $seconds); 
  } 
  return $time; 
}

$seconds = 3712; 
echo changeTimeType($seconds);