海运的博客

使用apt-get安装工具但是又不知道在哪个软件包中用apt-file解决：

apt-get install apt-file
apt-file update
apt-file search /usr/bin/dig

<?php
   function arr_foreach ($arr) 
   {
      static $tmp=array();  
      if (!is_array ($arr)) 
      {
         return false;
      }
      foreach ($arr as $val ) 
      {
         if (is_array ($val)) 
         {
            arr_foreach ($val);
         } 
         else 
         {
            $tmp[]=$val;
         }
      }
      return $tmp;
   }
   $a = array(1,2=>array(3,4=>array(5,6)),7);
   print_r(arr_foreach($a));
?>

使用for循环，只能遍历数字下标的数组：

<?php
   function arr_foreach($arr)
   {
      static $tmp=array();  

      for($i=0; $i<count($arr); $i++)
      {  
         if(is_array($arr[$i]))
         {  
            arr_foreach($arr[$i]);  
         }else{  
            $tmp[]=$arr[$i];  
         }  
      }  

      return $tmp;  
   }  
   $a = array(1,array(3,array(5,6)),7);
   print_r(arr_foreach($a));
?>

<?php
   function url_base64_encode($string) {
      $data = base64_encode($string);
      $data = str_replace(array('+','/','='),array('-','_',''),$data);
      return $data;
   }

   function url_base64_decode($string) {
      $data = str_replace(array('-','_'),array('+','/'),$string);
      $mod4 = strlen($data) % 4;
      if ($mod4) {
         $data .= substr('====', $mod4);
      }
      return base64_decode($data);
   }

   function encrypt($key, $str) {   
      $iv = mcrypt_create_iv(mcrypt_get_iv_size(MCRYPT_RIJNDAEL_128,MCRYPT_MODE_ECB),MCRYPT_DEV_URANDOM);
      $str_encrypt = mcrypt_encrypt(MCRYPT_RIJNDAEL_128,$key,$str,MCRYPT_MODE_ECB,$iv);
      return trim(url_base64_encode($str_encrypt));   
   }   

   function decrypt($key, $str_encrypt) {   
      $str_encrypt = trim(url_base64_decode($str_encrypt));   
      $iv = mcrypt_create_iv(mcrypt_get_iv_size(MCRYPT_RIJNDAEL_128,MCRYPT_MODE_ECB),MCRYPT_DEV_URANDOM);
      $str_decrypt = mcrypt_decrypt(MCRYPT_RIJNDAEL_128,$key,$str_encrypt,MCRYPT_MODE_ECB,$iv);
      return trim($str_decrypt);
   }
   echo encrypt('key','http://www.baidu.com////aaaa/bbbb/ccd//ddd')."\n";
   echo decrypt('key','zPsrxzCmqAAvlLwv4E7AlI346XTbaw1hAOoPZhtD3sKw__EIxmWpyHTEp4u2skGM')."\n";

?>

<?php
   if (getmxrr("qq.com", $mxhosts, $mxweights)) {

      foreach ($mxhosts as $host) {
         $hosts[] = dns_get_record($host, DNS_A);
      }
   }
   function getall_by_key(array $arr, $key){  
      if (!trim($key)) return false;  
      preg_match_all("/\"$key\";\w{1}:(?:\d+:|)(.*?);/", serialize($arr), $output);  
      return $output[1];  
   }  
   print_r(getall_by_key($hosts, 'ip'));  
?>

使用系统提供的flock函数：

<?php
   function ffwrite($filename,$content) {
      $file = fopen("$filename","a");
      while(1) {
         if (flock($file,LOCK_EX))
         {
            fwrite($file,$content);
            flock($file,LOCK_UN);
            fclose($file);
            break;
            } else {
            usleep(1000);
         }
      }
   }
?>

或根据创建文件判断其它进程是否在写操作，性能略差，测试1000次20进程写操作慢3%。

<?php
 function _fwrite($filename, $content) {
     $filename_lock = $filename . '.lock';
     while(1)
     {
         if(file_exists($filename_lock))
            {
             usleep(1000);
             } else {
             touch($filename_lock); 
             $f = fopen($filename, 'a');
             fwrite($f, "$content");
             fclose($f);
             unlink($filename_lock);
             break;
             }       
         }
     if(file_exists($filename_lock))
        {
         unlink($filename_lock);
         }
     }
 ?>