if condition not work wiht very large file in php -

i need read file server , boucle file read need. before condition if display work fine case large file or small. inside if not work large file. php code. first, use get_contents_file not wokr , change fread not work large files.

<!-- language: lang-html -->   function test_funct_campg($id_campg_x){          $dir = new directoryiterator("/var/log/test/");  ;         foreach ($dir $file) {                if ($file->isfile()){                if(preg_match('#actyn-#i', $file)){                        ini_set("memory_limit","70000m");                        $f = fopen($file->getfileinfo(), 'r');  $contents = fread($f, filesize($file->getfileinfo())); //fclose($f); $table = explode("\n", $contents);                       foreach ($table $row) {                         $str=explode('"', $row);                             $row=$str[0].$str[2];                            $fields=explode(',', $row);                         $email_address=$fields[5];                           $test_error=$fields[9];                         $id_campg=$fields[20];                   //  echo count($fields[20]);                 print_r($id_campg);// work in case large file or small display same id id_campg                            if($id_campg==$id_campg_x){  //$id_campg_x variable passed function                           print_r($id_campg); // work f fie not large                                }                      }                 }             }         }                }      enter code here