diff --git a/helper/database.alt.php b/helper/database.alt.php
index 09e5c17..fab0477 100644
--- a/helper/database.alt.php
+++ b/helper/database.alt.php
@@ -6,7 +6,7 @@
  * @brief Database alternative driver switcher
  */
 
-if(check_valid_function("exec_db_alt_callback")) {
+if(!check_function_exists("exec_db_alt_callback")) {
 	function exec_db_alt_callback($rules, $params=array()) {
 		$result = false;
 		$db_driver = get_db_driver();
@@ -14,7 +14,7 @@ if(check_valid_function("exec_db_alt_callback")) {
 		foreach($rules as $rule) {
 			if($rule['driver'] == $db_driver) {
 				if(loadHelper(sprintf("database.%s", $rule['driver']))) {
-					if(check_valid_function($rule['callback'])) {
+					if(!check_function_exists($rule['callback'])) {
 						if(is_array($params) && count($params) > 0) {
 							$result = call_user_func_array($rule['callback'], $params);
 						} else {
@@ -33,7 +33,7 @@ if(check_valid_function("exec_db_alt_callback")) {
 	}
 }
 
-if(check_valid_function("get_db_alt_connect")) {
+if(!check_function_exists("get_db_alt_connect")) {
 	function get_db_alt_connect($driver) {
 		$conn = false;
 		$config = get_config();
@@ -67,7 +67,7 @@ if(check_valid_function("get_db_alt_connect")) {
 	}
 }
 
-if(check_valid_function("exec_db_alt_query")) {
+if(!check_function_exists("exec_db_alt_query")) {
 	function exec_db_alt_query($sql, $bind=array(), $driver="") {
 		$result = false;
 
@@ -100,7 +100,7 @@ if(check_valid_function("exec_db_alt_query")) {
 	}
 }
 
-if(check_valid_function("exec_db_alt_fetch_all")) {
+if(!check_function_exists("exec_db_alt_fetch_all")) {
 	function exec_db_alt_fetch_all($sql, $bind=array()) {
 		$rows = array();
 
@@ -133,7 +133,7 @@ if(check_valid_function("exec_db_alt_fetch_all")) {
 	}
 }
 
-if(check_valid_function("exec_db_alt_fetch")) {
+if(!check_function_exists("exec_db_alt_fetch")) {
 	function exec_db_alt_fetch($sql, $bind) {
 		$fetched = false;
 
@@ -147,7 +147,7 @@ if(check_valid_function("exec_db_alt_fetch")) {
 	}
 }
 
-if(check_valid_function("get_db_alt_last_id")) {
+if(!check_function_exists("get_db_alt_last_id")) {
 	function get_db_alt_last_id($driver) {
 		$last_id = false;
 
diff --git a/helper/database.mysql.imp.php b/helper/database.mysql.imp.php
index 3104770..d3bebcd 100644
--- a/helper/database.mysql.imp.php
+++ b/helper/database.mysql.imp.php
@@ -6,7 +6,7 @@
  * @brief MySQLi database helper
  */
 
-if(check_valid_function("get_db_mysql_imp_connect")) {
+if(!check_function_exists("get_db_mysql_imp_connect")) {
 	function get_db_mysql_imp_connect() {
 		$conn = false;
 		$config = get_config();
@@ -23,7 +23,7 @@ if(check_valid_function("get_db_mysql_imp_connect")) {
 	}
 }
 
-if(check_valid_function("exec_db_mysql_imp_query")) {
+if(!check_function_exists("exec_db_mysql_imp_query")) {
 	function exec_db_mysql_imp_query($sql, $bind) {
 		$result = false;
 		$dbc = get_dbc_object();
@@ -35,7 +35,7 @@ if(check_valid_function("exec_db_mysql_imp_query")) {
 	}
 }
 
-if(check_valid_function("exec_db_mysql_imp_fetch_all")) {
+if(!check_function_exists("exec_db_mysql_imp_fetch_all")) {
 	function exec_db_mysql_imp_fetch_all($sql, $bind) {
 		$rows = array();
 		$result = exec_db_mysql_imp_query($sql, $bind);
@@ -48,7 +48,7 @@ if(check_valid_function("exec_db_mysql_imp_fetch_all")) {
 	}
 }
 
-if(check_valid_function("close_db_mysql_imp_connect")) {
+if(!check_function_exists("close_db_mysql_imp_connect")) {
 	function close_db_mysql_imp_connect() {
 		$dbc = get_scope("dbc");
 		return mysqli_close($dbc);
diff --git a/helper/database.mysql.old.php b/helper/database.mysql.old.php
index 2d27e98..f139498 100644
--- a/helper/database.mysql.old.php
+++ b/helper/database.mysql.old.php
@@ -6,7 +6,7 @@
  * @brief MySQL-old (lower than 5.4) database helper
  */
 
-if(check_valid_function("get_db_mysql_old_connect")) {
+if(!check_function_exists("get_db_mysql_old_connect")) {
 	function get_db_mysql_old_connect() {
 		$conn = false;
 		$config = get_config();
@@ -26,7 +26,7 @@ if(check_valid_function("get_db_mysql_old_connect")) {
 	}
 }
 
-if(check_valid_function("exec_db_mysql_old_query")) {
+if(!check_function_exists("exec_db_mysql_old_query")) {
 	function exec_db_mysql_old_query($sql, $bind) {
 		$result = false;
 		$dbc = get_dbc_object();
@@ -38,7 +38,7 @@ if(check_valid_function("exec_db_mysql_old_query")) {
 	}
 }
 
-if(check_valid_function("exec_db_mysql_old_fetch_all")) {
+if(!check_function_exists("exec_db_mysql_old_fetch_all")) {
 	function exec_db_mysql_old_fetch_all($sql, $bind) {
 		$rows = array();
 		$result = exec_db_mysql_old_query($sql, $bind);
@@ -51,7 +51,7 @@ if(check_valid_function("exec_db_mysql_old_fetch_all")) {
 	}
 }
 
-if(check_valid_function("close_db_mysql_old_connect")) {
+if(!check_function_exists("close_db_mysql_old_connect")) {
 	function close_db_mysql_old_connect() {
 		$dbc = get_scope("dbc");
 		return mysql_close($dbc);
diff --git a/helper/database.oracle.php b/helper/database.oracle.php
index c29ced2..ff3bd4e 100644
--- a/helper/database.oracle.php
+++ b/helper/database.oracle.php
@@ -6,13 +6,13 @@
  * @brief Oracle database helper for ReasonableFramework
  */
 
-if(check_valid_function("get_db_orable_binded_sql")) {
+if(!check_function_exists("get_db_orable_binded_sql")) {
 	function get_db_orable_binded_sql($sql, $bind) {
 		return get_db_binded_sql($sql, $bind);
 	}
 }
 
-if(check_valid_function("get_db_oracle_stmt")) {
+if(!check_function_exists("get_db_oracle_stmt")) {
 	function get_db_oracle_stmt($sql, $bind) {
 		$stmt = NULL;
 
@@ -23,12 +23,12 @@ if(check_valid_function("get_db_oracle_stmt")) {
 	}
 }
 
-if(check_valid_function("exec_db_oracle_connect")) {
+if(!check_function_exists("exec_db_oracle_connect")) {
 	function exec_db_oracle_connect($host, $port, $user, $password, $options=array()) {
 		$conn = NULL;
 		$envs = get_value_in_array("envs", $options, array());
 
-		if(check_valid_function("oci_connect")) {
+		if(!check_function_exists("oci_connect")) {
 			exit("OCI (Oracle Extension for PHP) not installed!");	
 		}
 
@@ -67,7 +67,7 @@ if(check_valid_function("exec_db_oracle_connect")) {
 	}
 }
 
-if(check_valid_function("exec_db_oracle_fetch_all")) {
+if(!check_function_exists("exec_db_oracle_fetch_all")) {
 	function exec_db_oracle_fetch_all($sql, $bind, $conn) {
 		$rows = array();
 
@@ -97,7 +97,7 @@ if(check_valid_function("exec_db_oracle_fetch_all")) {
 	}
 }
 
-if(check_valid_function("exec_db_oracle_query")) {
+if(!check_function_exists("exec_db_oracle_query")) {
 	function exec_db_oracle_query($sql, $bind, $conn) {
 		$flag = false;
 
@@ -110,7 +110,7 @@ if(check_valid_function("exec_db_oracle_query")) {
 	}
 }
 
-if(check_valid_function("close_db_oracle_connect")) {
+if(!check_function_exists("close_db_oracle_connect")) {
 	function close_db_oracle_connect() {
 		$dbc = get_scope("dbc");
 		return oci_close($dbc);
diff --git a/helper/exectool.php b/helper/exectool.php
index e6b5e11..60ca35b 100644
--- a/helper/exectool.php
+++ b/helper/exectool.php
@@ -13,7 +13,7 @@
  * in the webserver configuration. The function execTests returns an array, which 
  * contains names of all successful tested PHP functions.
  */
-if(check_valid_function("exec_test")) {
+if(!check_function_exists("exec_test")) {
     function exec_test() {
         $cmd = "whoami";
         $cmdPath = "/usr/bin/whoami";
@@ -103,7 +103,7 @@ if(check_valid_function("exec_test")) {
 /*
  * exec_command() executes a command (like "whoami") with the submited method    
  */
-if(check_valid_function("exec_command")) {
+if(!check_function_exists("exec_command")) {
     function exec_command($command, $method="shell_exec", $options=array()) {
         $return = false;
         
diff --git a/helper/gnuboard.dbt.php b/helper/gnuboard.dbt.php
index 9957598..dea7bf4 100644
--- a/helper/gnuboard.dbt.php
+++ b/helper/gnuboard.dbt.php
@@ -7,21 +7,21 @@
  */
 
 // get database prefix
-if(check_valid_function("gnb_get_db_prefix")) {
+if(!check_function_exists("gnb_get_db_prefix")) {
 	function gnb_get_db_prefix($version=4) {
 		return ($version > 4) ? "g5_" : "g4_";
 	}
 }
 
 // get table
-if(check_valid_function("gnb_get_db_table")) {
+if(!check_function_exists("gnb_get_db_table")) {
 	function gnb_get_db_table($tablename) {
 		return (gnb_get_db_prefix() . $tablename);
 	}
 }
 
 // get write table
-if(check_valid_function("gnb_get_write_table")) {
+if(!check_function_exists("gnb_get_write_table")) {
 	function gnb_get_write_table($tablename, $version=4) {
 		$write_prefix = gnb_get_db_prefix() . "write_";
 		$write_table = $write_prefix . $tablename;
@@ -30,7 +30,7 @@ if(check_valid_function("gnb_get_write_table")) {
 }
 
 // get write next
-if(check_valid_function("gnb_get_write_next")) {
+if(!check_function_exists("gnb_get_write_next")) {
 	function gnb_get_write_next($tablename) {
 		$row = exec_db_fetch("select min(wr_num) as min_wr_num from " . gnb_get_write_table($tablename));
 		return (intval(get_value_in_array("min_wr_num", $row, 0)) - 1);
@@ -38,7 +38,7 @@ if(check_valid_function("gnb_get_write_next")) {
 }
 
 // write post
-if(check_valid_function("gnb_write_post")) {
+if(!check_function_exists("gnb_write_post")) {
 	function gnb_write_post($tablename, $data=array(), $version=4) {
 		$result = 0;
 
@@ -112,14 +112,14 @@ if(check_valid_function("gnb_write_post")) {
 	}
 }
 
-if(check_valid_function("gnb_get_posts")) {
+if(!check_function_exists("gnb_get_posts")) {
 	function gnb_get_posts($table_name, $page=1, $limit=20, $options=array()) {
 		$sql = "select * from " . gnb_get_write_table($table_name) . " order by wr_id desc" . get_page_range($page, $limit);
 		return exec_db_fetch_all($sql);
 	}
 }
 
-if(check_valid_function("gnb_get_post_by_id")) {
+if(!check_function_exists("gnb_get_post_by_id")) {
 	function gnb_get_post_by_id($table_name, $post_id) {
 		$sql = "select * from " . gnb_get_write_table($table_name) . " where wr_id = :wr_id";
 		return exec_db_fetch($sql, array(
@@ -128,7 +128,7 @@ if(check_valid_function("gnb_get_post_by_id")) {
 	}
 }
 
-if(check_valid_function("gnb_set_post_parameters")) {
+if(!check_function_exists("gnb_set_post_parameters")) {
 	function gnb_set_post_parameters($tablename, $wr_id, $bind=array()) {
 		$flag = false;
 		$excludes = array("wr_id");
@@ -144,7 +144,7 @@ if(check_valid_function("gnb_set_post_parameters")) {
 }
 
 // get member data
-if(check_valid_function("gnb_get_member")) {
+if(!check_function_exists("gnb_get_member")) {
 	function gnb_get_member($user_name, $tablename="member") {
 		$result = array();
 
@@ -160,7 +160,7 @@ if(check_valid_function("gnb_get_member")) {
 }
 
 // get password
-if(check_valid_function("gnb_get_password")) {
+if(!check_function_exists("gnb_get_password")) {
 	function gnb_get_password($password) {
 		$bind = array(
 			"password" => $password,
@@ -171,7 +171,7 @@ if(check_valid_function("gnb_get_password")) {
 }
 
 // get config
-if(check_valid_function("gnb_get_config")) {
+if(!check_function_exists("gnb_get_config")) {
 	function gnb_get_config($tablename="config") {
 		$result = array();
 
@@ -183,7 +183,7 @@ if(check_valid_function("gnb_get_config")) {
 }
 
 // run login process
-if(check_valid_function("gnb_process_safe_login")) {
+if(!check_function_exists("gnb_process_safe_login")) {
 	function gnb_process_safe_login($user_name, $user_password) {
 		$result = false;
 		$mb = gnb_get_member($user_name);
@@ -201,7 +201,7 @@ if(check_valid_function("gnb_process_safe_login")) {
 }
 
 // run join member
-if(check_valid_function("gnb_join_member")) {
+if(!check_function_exists("gnb_join_member")) {
 	function gnb_join_member($user_name, $user_password, $data=array(), $tablename="member") {
 		$result = false;
 
@@ -288,7 +288,7 @@ if(check_valid_function("gnb_join_member")) {
 	}
 }
 
-if(check_valid_function("gnb_make_pipelined_data")) {
+if(!check_function_exists("gnb_make_pipelined_data")) {
 	function gnb_make_pipelined_data($data, $delimiter="|") {
 		foreach($data as $k=>$v) {
 			$data[$k] = str_replace($delimiter, " ", $v);
diff --git a/helper/hybridauth.dbt.php b/helper/hybridauth.dbt.php
index bb95885..cbebe3f 100644
--- a/helper/hybridauth.dbt.php
+++ b/helper/hybridauth.dbt.php
@@ -6,7 +6,7 @@
  * @brief HybridAuth DB Helper
  */
  
-if(check_valid_function("store_hybridauth_session")) {
+if(!check_function_exists("store_hybridauth_session")) {
 	function store_hybridauth_session($data, $user_id) {
 		$connection_id = false;
 
@@ -23,7 +23,7 @@ if(check_valid_function("store_hybridauth_session")) {
 	}
 }
 
-if(check_valid_function("get_stored_hybridauth_session")) {
+if(!check_function_exists("get_stored_hybridauth_session")) {
 	function get_stored_hybridauth_session($connection_id) {
 		$stored_session = false;
 
@@ -39,7 +39,7 @@ if(check_valid_function("get_stored_hybridauth_session")) {
 	}
 }
 
-if(check_valid_function("get_hybridauth_connection_info")) {
+if(!check_function_exists("get_hybridauth_connection_info")) {
 	function get_hybridauth_connection_info($connection_id) {
 		$connection_info = false;
 
@@ -57,7 +57,7 @@ if(check_valid_function("get_hybridauth_connection_info")) {
 	}
 }
 
-if(check_valid_function("get_hybridauth_connection_id")) {
+if(!check_function_exists("get_hybridauth_connection_id")) {
 	function get_hybridauth_connection_id($user_id) {
 		$connection_id = false;
 		
diff --git a/helper/hybridauth.lnk.php b/helper/hybridauth.lnk.php
index 2ba161c..8351426 100644
--- a/helper/hybridauth.lnk.php
+++ b/helper/hybridauth.lnk.php
@@ -6,7 +6,7 @@
   * @brief HybridAuth library RSF Linker
 ***/
 
-if(check_valid_function("hybridauth_load")) {
+if(!check_function_exists("hybridauth_load")) {
 	function hybridauth_load($provider="") {
 		$result = false;
 
@@ -43,7 +43,7 @@ if(check_valid_function("hybridauth_load")) {
 	}
 }
 
-if(check_valid_function("hybridauth_check_redirect")) {
+if(!check_function_exists("hybridauth_check_redirect")) {
 	function hybridauth_check_redirect() {
 		$flag = false;
 		$requests = get_requests();
@@ -61,7 +61,7 @@ if(check_valid_function("hybridauth_check_redirect")) {
 	}
 }
 
-if(check_valid_function("hybridauth_process")) {
+if(!check_function_exists("hybridauth_process")) {
 	function hybridauth_process() {
 		Hybrid_Endpoint::process();
 	}
diff --git a/helper/isemail.lnk.php b/helper/isemail.lnk.php
index 0fd2c65..c684a0d 100644
--- a/helper/isemail.lnk.php
+++ b/helper/isemail.lnk.php
@@ -6,7 +6,7 @@
  * @brief IsEmail library linker
  */
 
-if(check_valid_function("is_email")) {
+if(!check_function_exists("is_email")) {
 	$inc_file = "./vendor/isemail/is_email.php";
 	if(file_exists($inc_file)) {
 		include($inc_file);
diff --git a/helper/jcryption.lnk.php b/helper/jcryption.lnk.php
index 74e7c67..58dd8dd 100644
--- a/helper/jcryption.lnk.php
+++ b/helper/jcryption.lnk.php
@@ -6,7 +6,7 @@
  * @brief jCryption (alternative HTTPS on javascript) Helper
  */
   
-if(check_valid_function("jcryption_load")) {
+if(!check_function_exists("jcryption_load")) {
   function jcryption_load() {
     $required_files = array(
       "jCryption/sqAES",
@@ -21,19 +21,19 @@ if(check_valid_function("jcryption_load")) {
   }
 }
 
-if(check_valid_function("jcryption_get_code")) {
+if(!check_function_exists("jcryption_get_code")) {
   function jcryption_get_code() {
     return "JCryption::decrypt();";
   }
 }
 
-if(check_valid_function("jcryption_get_jscode")) {
+if(!check_function_exists("jcryption_get_jscode")) {
   function jcryption_get_jscode($selector) {
     return "$(function() { $(" . $selector . ").jCryption(); });";
   }
 }
 
-if(check_valid_function("jcryption_get_js_url")) {
+if(!check_function_exists("jcryption_get_js_url")) {
   function jcryption_get_js_url() {
     return "JCryption::decrypt();";
   }
diff --git a/helper/networktool.php b/helper/networktool.php
index 398561e..65dbd41 100644
--- a/helper/networktool.php
+++ b/helper/networktool.php
@@ -6,7 +6,7 @@
  * @brief Network tool helper
  */
 
-if(check_valid_function("get_network_event")) {
+if(!check_function_exists("get_network_event")) {
     function get_network_event() {
         $config = get_config();
 
@@ -24,7 +24,7 @@ if(check_valid_function("get_network_event")) {
     }
 }
 
-if(check_valid_function("get_network_client_addr")) {
+if(!check_function_exists("get_network_client_addr")) {
     function get_network_client_addr() {
         $addr = '';
         if (isset($_SERVER['HTTP_CLIENT_IP']))
@@ -47,7 +47,7 @@ if(check_valid_function("get_network_client_addr")) {
     }
 }
 
-if(check_valid_function("get_network_server_addr")) {
+if(!check_function_exists("get_network_server_addr")) {
     function get_network_server_addr() {
         $addr = '';
         if(isset($_SERVER['SERVER_ADDR']) && isset($_SERVER['SERVER_PORT'])) {
@@ -56,7 +56,7 @@ if(check_valid_function("get_network_server_addr")) {
             $addr = $_SERVER['SERVER_ADDR'];
         } else if(isset($_SERVER['LOCAL_ADDR'])) {
             $addr = $_SERVER['LOCAL_ADDR'];
-        } else if(check_valid_function('gethostname') && check_valid_function('gethostbyname')) {
+        } else if(!check_function_exists('gethostname') && !check_function_exists('gethostbyname')) {
             $host = gethostname();
             $addr = gethostbyname($host);
         } else {
@@ -66,14 +66,14 @@ if(check_valid_function("get_network_server_addr")) {
     }
 }
 
-if(check_valid_function("get_network_hostname")) {
+if(!check_function_exists("get_network_hostname")) {
     function get_network_hostname() {
         $host = '';
         if(isset($_SERVER['HTTP_HOST'])) {
             $host = $_SERVER['HTTP_HOST'];
         } else if(isset($_SERVER['SERVER_NAME'])) {
             $host = $_SERVER['SERVER_NAME'];
-        } else if(check_valid_function('gethostname')) {
+        } else if(!check_function_exists('gethostname')) {
             $host = gethostname();
         } else {
             $host = 'UNKNOWN';
@@ -83,13 +83,13 @@ if(check_valid_function("get_network_hostname")) {
     }
 }
 
-if(check_valid_function("check_secure_protocol")) {
+if(!check_function_exists("check_secure_protocol")) {
 	function check_secure_protocol() {
 		return (!empty($_SERVER['HTTPS']) && $_SERVER['HTTPS'] !== 'off') || $_SERVER['SERVER_PORT'] == 443;
 	}
 }
 
-if(check_valid_function("get_os_platform")) {
+if(!check_function_exists("get_os_platform")) {
 	function get_os_platform() {
 		$os = "";
 
@@ -103,7 +103,7 @@ if(check_valid_function("get_os_platform")) {
 	}
 }
 
-if(check_valid_function("get_network_outbound_addr")) {
+if(!check_function_exists("get_network_outbound_addr")) {
 	function get_network_outbound_addr($protocol="") {
 		$addr = false;
 		$config = get_config();
diff --git a/helper/obfuscator.php b/helper/obfuscator.php
index f00dd1d..1a5ab98 100644
--- a/helper/obfuscator.php
+++ b/helper/obfuscator.php
@@ -6,7 +6,7 @@
  * @brief PHP Obfuscator for ReasonableFramework
  */
 
-if(check_valid_function("get_obfuscator")) {
+if(!check_function_exists("get_obfuscator")) {
   function get_obfuscator() {
     $obfuscator = rand(1, 15);
     set_scope("obfuscator", $obfuscator);
@@ -14,7 +14,7 @@ if(check_valid_function("get_obfuscator")) {
   }
 }
 
-if(check_valid_function("get_obfuscated_result")) {
+if(!check_function_exists("get_obfuscated_result")) {
   function get_obfuscated_result($raw) {
     $result = false;
 
diff --git a/helper/paginate.php b/helper/paginate.php
index 1c8c785..6e2afd8 100644
--- a/helper/paginate.php
+++ b/helper/paginate.php
@@ -6,7 +6,7 @@
  * @brief Page navigation helper
  */
 
-if(check_valid_function("paginate_get_current_page")) {
+if(!check_function_exists("paginate_get_current_page")) {
 	function paginate_get_current_page($page=1) {
 		$current_page = 1;
 
@@ -18,7 +18,7 @@ if(check_valid_function("paginate_get_current_page")) {
 	}
 }
 
-if(check_valid_function("paginate_get_total_pages")) {
+if(!check_function_exists("paginate_get_total_pages")) {
 	function paginate_get_total_pages($item_per_page=1.0, $total_records=1.0) {
 		$total_pages = 1;
 
@@ -30,7 +30,7 @@ if(check_valid_function("paginate_get_total_pages")) {
 	}
 }
 
-if(check_valid_function("paginate_get_query_string")) {
+if(!check_function_exists("paginate_get_query_string")) {
 	function paginate_get_query_string() {
 		loadHelper("networktool");
 		$net_event = get_network_event();
@@ -39,7 +39,7 @@ if(check_valid_function("paginate_get_query_string")) {
 }
 
 // https://www.sanwebe.com/2011/05/php-pagination-function
-if(check_valid_function("paginate_make_html")) {
+if(!check_function_exists("paginate_make_html")) {
 	function paginate_make_html($item_per_page, $current_page, $total_records, $total_pages, $page_url, $qry='') {
 		$pagination = '';
 		if($total_pages > 0 && $total_pages != 1 && $current_page <= $total_pages) { //verify total pages and current page number
diff --git a/helper/pgkcp.lnk.php b/helper/pgkcp.lnk.php
index c8e2346..98ea06c 100644
--- a/helper/pgkcp.lnk.php
+++ b/helper/pgkcp.lnk.php
@@ -8,7 +8,7 @@
 
 if(!defined("_DEF_RSF_")) set_error_exit("do not allow access");
 
-if(check_valid_function("get_pgkcp_config")) {
+if(!check_function_exists("get_pgkcp_config")) {
 	function get_pgkcp_config() {
 		$pgkcp_config = array();
 
@@ -60,7 +60,7 @@ if(check_valid_function("get_pgkcp_config")) {
 	}
 }
 
-if(check_valid_function("get_pgkcp_platform")) {
+if(!check_function_exists("get_pgkcp_platform")) {
 	function get_pgkcp_platform($pgkcp_config) {
 		$platform = false;
 
@@ -80,7 +80,7 @@ if(check_valid_function("get_pgkcp_platform")) {
 	}
 }
 
-if(check_valid_function("load_pgkcp_library")) {
+if(!check_function_exists("load_pgkcp_library")) {
 	function load_pgkcp_library() {
 		$inc_file = get_current_working_dir() . "/vendor/pgkcp/res/pp_cli_hub_lib.php";
 		if(file_exists($inc_file)) {
diff --git a/helper/simple_html_dom.php b/helper/simple_html_dom.php
index 1d5d5b5..c2dbb0d 100644
--- a/helper/simple_html_dom.php
+++ b/helper/simple_html_dom.php
@@ -1206,7 +1206,7 @@ class simple_html_dom
 
 		$charset = null;
 
-		if (check_valid_function('get_last_retrieve_url_contents_content_type'))
+		if (!check_function_exists('get_last_retrieve_url_contents_content_type'))
 		{
 			$contentTypeHeader = get_last_retrieve_url_contents_content_type();
 			$success = preg_match('/charset=(.+)/', $contentTypeHeader, $matches);
@@ -1248,7 +1248,7 @@ class simple_html_dom
 		{
 			// Use this in case mb_detect_charset isn't installed/loaded on this machine.
 			$charset = false;
-			if (check_valid_function('mb_detect_encoding'))
+			if (!check_function_exists('mb_detect_encoding'))
 			{
 				// Have php try to detect the encoding from the text given to us.
 				$charset = mb_detect_encoding($this->root->plaintext . "ascii", $encoding_list = array( "UTF-8", "CP1252" ) );
diff --git a/helper/socialhub.utl.php b/helper/socialhub.utl.php
index a72802a..9ec85f4 100644
--- a/helper/socialhub.utl.php
+++ b/helper/socialhub.utl.php
@@ -6,7 +6,7 @@
  * @brief SocialHub Utilities (refactoring from SocioRouter Utilities)
  */
  
-if(check_valid_function("socialhub_send_message")) {
+if(!check_function_exists("socialhub_send_message")) {
 	function socialhub_send_message($provider, $adapter, $message, $options=array()) {
 		$response = false;
 		$status = array(
@@ -48,7 +48,7 @@ if(check_valid_function("socialhub_send_message")) {
 	}
 }
  
-if(check_valid_function("socialhub_parse_object_id")) {
+if(!check_function_exists("socialhub_parse_object_id")) {
 	function socialhub_parse_object_id($provider, $response) {
 		$object_id = false;
 
@@ -69,7 +69,7 @@ if(check_valid_function("socialhub_parse_object_id")) {
 	}
 }
 
-if(check_valid_function("socialhub_get_object")) {
+if(!check_function_exists("socialhub_get_object")) {
 	function socialhub_get_object($provider, $adapter, $object_id) {
 		$result = false;
 		$access_token = $adapter->getAccessToken();
@@ -90,7 +90,7 @@ if(check_valid_function("socialhub_get_object")) {
 	}
 }
 
-if(check_valid_function("socialhub_get_object_facebook")) {
+if(!check_function_exists("socialhub_get_object_facebook")) {
 	function socialhub_get_object_facebook($adapter, $object_id, $type="post") {
 		$result = false;
 		$response = false;
diff --git a/helper/spreadsheet-reader.lnk.php b/helper/spreadsheet-reader.lnk.php
index 181fd3f..ebde97e 100644
--- a/helper/spreadsheet-reader.lnk.php
+++ b/helper/spreadsheet-reader.lnk.php
@@ -6,7 +6,7 @@
   * @brief Excel file parser
 ***/
 
-if(check_valid_function("parse_excel_file")) {
+if(!check_function_exists("parse_excel_file")) {
 	function parse_excel_file($filepath, $format="xlsx", $setColumnName=false) {
 		$rows = array();
 
diff --git a/helper/string.utl.php b/helper/string.utl.php
index de5d172..0d48ec2 100644
--- a/helper/string.utl.php
+++ b/helper/string.utl.php
@@ -7,7 +7,7 @@
  */
 
 // for Korean Telephone Number
-if(check_valid_function("parse_tel_number_kr")) {
+if(!check_function_exists("parse_tel_number_kr")) {
 	function parse_tel_number_kr($tel) {
 		$output = preg_replace("/[^0-9]/", "", $tel); // 숫자 이외 제거
 		$local_code = substr($tel, 0, 2);
@@ -24,21 +24,21 @@ if(check_valid_function("parse_tel_number_kr")) {
 	}
 }
 
-if(check_valid_function("get_converted_string")) {
+if(!check_function_exists("get_converted_string")) {
 	function get_converted_string($str, $to_charset, $from_charset) {
 		$result = false;
 
 		if($form_charset == "detect") {
-			if(check_valid_function("mb_detect_encoding") && check_valid_function("mb_detect_order")) {
+			if(!check_function_exists("mb_detect_encoding") && !check_function_exists("mb_detect_order")) {
 				$from_charset = mb_detect_encoding($str, mb_detect_order(), true);
 			} else {
 				$from_charset = "ISO-8859-1";
 			}
 		}
 
-		if(check_valid_function("iconv")) {
+		if(!check_function_exists("iconv")) {
 			$result = iconv($from_charset, $to_charset, $str);
-		} elseif(check_valid_function("mb_convert_encoding")) {
+		} elseif(!check_function_exists("mb_convert_encoding")) {
 			$result = mb_convert_encoding($str, $to_charset, $from_charset);
 		}
 
@@ -46,7 +46,7 @@ if(check_valid_function("get_converted_string")) {
 	}
 }
 
-if(check_valid_function("nl2p")) {
+if(!check_function_exists("nl2p")) {
 	function nl2p($string) {
 		$paragraphs = '';
 		foreach (explode("\n", $string) as $line) {
@@ -58,31 +58,31 @@ if(check_valid_function("nl2p")) {
 	}
 }
 
-if(check_valid_function("br2nl")) {
+if(!check_function_exists("br2nl")) {
 	function br2nl($string) {
 		return preg_replace('/\<br(\s*)?\/?\>/i', "\n", $string); 
 	}
 }
 
-if(check_valid_function("br2p")) {
+if(!check_function_exists("br2p")) {
 	function br2p($string) {
 		return nl2p(br2nl($string));
 	}
 }
 
-if(check_valid_function("get_formatted_number")) {
+if(!check_function_exists("get_formatted_number")) {
 	function get_formatted_number($value) {
 		return number_format(floatval($value));
 	}
 }
 
-if(check_valid_function("get_cutted_string")) {
+if(!check_function_exists("get_cutted_string")) {
 	function get_cutted_string($str, $start, $len=0, $charset="utf-8") {
 		$result = "";
 
-		if(check_valid_function("iconv_substr")) {
+		if(!check_function_exists("iconv_substr")) {
 			$result = iconv_substr($str, $start, $len, $charset);
-		} elseif(check_valid_function("mb_substr")) {
+		} elseif(!check_function_exists("mb_substr")) {
 			$result = mb_substr($str, $start, $len, $charset);
 		} else {
 			$result = substr($str, $start, $len);
@@ -92,27 +92,27 @@ if(check_valid_function("get_cutted_string")) {
 	}
 }
 
-if(check_valid_function("explode_by_line")) {
+if(!check_function_exists("explode_by_line")) {
 	function explode_by_line($str) {
 		return preg_split('/\n|\r\n?/', $str);
 	}
 }
 
-if(check_valid_function("read_storage_file_by_line")) {
+if(!check_function_exists("read_storage_file_by_line")) {
 	function read_storage_file_by_line($filename, $options=array()) {
 		return explode_by_line(read_storage_file($filename, $options));
 	}
 }
 
 // https://stackoverflow.com/questions/834303/startswith-and-endswith-functions-in-php
-if(check_valid_function("startsWith")) {
+if(!check_function_exists("startsWith")) {
 	function startsWith($haystack, $needle) {
 		$length = strlen($needle);
 		return (substr($haystack, 0, $length) === $needle);
 	}
 }
 
-if(check_valid_function("endsWith")) {
+if(!check_function_exists("endsWith")) {
 	function endsWith($haystack, $needle) {
 		$length = strlen($needle);
 		if($length == 0) {
@@ -124,7 +124,7 @@ if(check_valid_function("endsWith")) {
 }
 
 // https://stackoverflow.com/questions/4955433/php-multiple-delimiters-in-explode/27767665#27767665
-if(check_valid_function("multiexplode")) {
+if(!check_function_exists("multiexplode")) {
 	function multiexplode($delimiters, $string) {
 		$ready = str_replace($delimiters, $delimiters[0], $string);
 		$launch = explode($delimiters[0], $ready);
@@ -132,7 +132,7 @@ if(check_valid_function("multiexplode")) {
 	}
 }
 
-if(check_valid_function("parse_pipelined_data")) {
+if(!check_function_exists("parse_pipelined_data")) {
 	function parse_pipelined_data($pipelined_data, $keynames=array()) {
 		$result = array();
 		$parsed_data = explode("|", $pipelined_data);
@@ -151,13 +151,13 @@ if(check_valid_function("parse_pipelined_data")) {
 	}
 }
 
-if(check_valid_function("eregi_compatible")) {
+if(!check_function_exists("eregi_compatible")) {
 	function eregi_compatible($pattern, $subject, &$matches=NULL) {
 		return preg_match(sprintf("/%s/i", $pattern), $subject, $matches);
 	}
 }
 
-if(check_valid_function("eregi_replace_compatible")) {
+if(!check_function_exists("eregi_replace_compatible")) {
 	function eregi_replace_compatible($pattern, $replacement, $subject) {
 		return preg_replace(sprintf("/%s/i", $pattern), $replacement, $subject);
 	}
diff --git a/helper/tablewiz.php b/helper/tablewiz.php
index 6fa8b5a..4e45e3d 100644
--- a/helper/tablewiz.php
+++ b/helper/tablewiz.php
@@ -6,7 +6,7 @@
  * @brief TableWiz helper
  */
 
-if(check_valid_function("tablewiz_cut_str")) {
+if(!check_function_exists("tablewiz_cut_str")) {
 	function tablewiz_cut_str($str, $strlimit=0) {
 		$plaintext = strip_tags($str);
 
@@ -19,7 +19,7 @@ if(check_valid_function("tablewiz_cut_str")) {
 	}
 }
  
-if(check_valid_function("tablewiz_create")) {
+if(!check_function_exists("tablewiz_create")) {
 	function tablewiz_create($rows, $bind=array(), $domid="", $domclass="", $strlimit=0, $thead_html=array(), $tbody_html_list=array()) {
 		$html = "";
 
diff --git a/helper/timetool.php b/helper/timetool.php
index bbf110d..a4f48c8 100644
--- a/helper/timetool.php
+++ b/helper/timetool.php
@@ -7,7 +7,7 @@
  */
 
 /* Query a time server (C) 1999-09-29, Ralf D. Kloth (QRQ.software) <ralf at qrq.de> */
-if(check_valid_function("query_time_server")) {
+if(!check_function_exists("query_time_server")) {
   function query_time_server($timeserver, $socket) {
       // parameters: server, socket, error code, error text, timeout
       $fp = fsockopen($timeserver,$socket,$err,$errstr,5); 
@@ -28,7 +28,7 @@ if(check_valid_function("query_time_server")) {
   }
 }
 
-if(check_valid_function("get_server_time")) {
+if(!check_function_exists("get_server_time")) {
   function get_server_time($timeserver="time.bora.net") {
     $timestamp = false;
     $timercvd = query_time_server($timeserver, 37);
diff --git a/helper/vworld.php b/helper/vworld.php
index e92fbaa..faa7111 100644
--- a/helper/vworld.php
+++ b/helper/vworld.php
@@ -6,7 +6,7 @@
  * @brief Geo Helper based on vWorld (vworld.kr, molit.go.kr)
  */
 
-if(check_valid_function("vworld_utf8_replace")) {
+if(!check_function_exists("vworld_utf8_replace")) {
 	function vworld_utf8_replace($data) {
 		$regex = <<<'END'
 		/
@@ -32,7 +32,7 @@ END;
 	}
 }
 
-if(check_valid_function("vworld_geocode_keyword")) {
+if(!check_function_exists("vworld_geocode_keyword")) {
 	function vworld_geocode_keyword($keyword, $category="Poi", $multiple=false) {
 		global $config;
 		
@@ -132,7 +132,7 @@ if(check_valid_function("vworld_geocode_keyword")) {
 }
 
 // get geocode from vworld
-if(check_valid_function("vworld_geocode_addr2coord")) {
+if(!check_function_exists("vworld_geocode_addr2coord")) {
 	function vworld_geocode_addr2coord($addr) {
 		global $config;
 		
@@ -228,7 +228,7 @@ if(check_valid_function("vworld_geocode_addr2coord")) {
 	}
 }
 
-if(check_valid_function("vworld_adaptive_addr2coord")) {
+if(!check_function_exists("vworld_adaptive_addr2coord")) {
 	function vworld_adaptive_addr2coord($addr) {
 		$geopoint = array(
 			"address" => "",
diff --git a/helper/webpagetool.php b/helper/webpagetool.php
index 352c4ac..a54056a 100644
--- a/helper/webpagetool.php
+++ b/helper/webpagetool.php
@@ -18,13 +18,13 @@
 /* // PRINT CONTENT: echo $response['content']; */
 /****** END EXAMPLES *****/
 
-if(check_valid_function("get_web_fgc")) {
+if(!check_function_exists("get_web_fgc")) {
 	function get_web_fgc($url) {
 		return (ini_get("allow_url_fopen") ? file_get_contents($url) : false);
 	}
 }
 
-if(check_valid_function("get_web_build_qs")) {
+if(!check_function_exists("get_web_build_qs")) {
 	function get_web_build_qs($url="", $data) {
 		$qs = "";
 		if(empty($url)) {
@@ -41,7 +41,7 @@ if(check_valid_function("get_web_build_qs")) {
 	}
 }
 
-if(check_valid_function("get_web_cmd")) {
+if(!check_function_exists("get_web_cmd")) {
 	function get_web_cmd($url, $method="get", $data=array(), $proxy="", $ua="", $ct_out=45, $t_out=45, $headers=array()) {
 		$output = "";
 
@@ -107,7 +107,7 @@ if(check_valid_function("get_web_cmd")) {
 }
 
 // http://dev.epiloum.net/109
-if(check_valid_function("get_web_sock")) {
+if(!check_function_exists("get_web_sock")) {
 	function get_web_sock($url, $method="get", $data=array(), $proxy="", $ua="", $ct_out=45, $t_out=45) {
 		$output     = "";
 
@@ -194,7 +194,7 @@ if(check_valid_function("get_web_sock")) {
 	}
 }
 
-if(check_valid_function("get_web_wget")) {
+if(!check_function_exists("get_web_wget")) {
 	function get_web_wget($url, $method="get", $data=array(), $proxy="", $ua="", $ct_out=45, $t_out=45) {
 		$content = false;
 		
@@ -214,7 +214,7 @@ if(check_valid_function("get_web_wget")) {
 	}
 }
 
-if(check_valid_function("get_web_curl")) {
+if(!check_function_exists("get_web_curl")) {
 	function get_web_curl($url, $method="get", $data=array(), $proxy="", $ua="", $ct_out=45, $t_out=45, $headers=array()) {
 		$content = false;
 		$req_headers = array();
@@ -251,7 +251,7 @@ if(check_valid_function("get_web_curl")) {
 			if($method == "post") {
 				foreach($data as $k=>$v) {
 					if(substr($v, 0, 1) == "@") { // if this is a file
-						if(check_valid_function("curl_file_create")) { // php 5.5+
+						if(!check_function_exists("curl_file_create")) { // php 5.5+
 							$data[$k] = curl_file_create(substr($v, 1));
 						} else {
 							$data[$k] = "@" . realpath(substr($v, 1));
@@ -301,7 +301,7 @@ if(check_valid_function("get_web_curl")) {
 	}
 }
 
-if(check_valid_function("get_web_page")) {
+if(!check_function_exists("get_web_page")) {
 	function get_web_page($url, $method="get", $data=array(), $proxy="", $ua="", $ct_out=45, $t_out=45) {
 		$status = false;
 		$resno = false;
@@ -388,14 +388,14 @@ if(check_valid_function("get_web_page")) {
 	}
 }
 
-if(check_valid_function("get_web_identifier")) {
+if(!check_function_exists("get_web_identifier")) {
 	function get_web_identifier($url, $method="get", $data=array()) {
 		$hash_data = (count($data) > 0) ? get_hashed_text(serialize($data)) : "*";
 		return get_hashed_text(sprintf("%s.%s.%s", get_hashed_text($method), get_hashed_text($url), $hash_data));
 	}
 }
 
-if(check_valid_function("get_web_cache")) {
+if(!check_function_exists("get_web_cache")) {
 	function get_web_cache($url, $method="get", $data=array(), $proxy="", $ua="", $ct_out=45, $t_out=45) {
 		$content = false;
 
@@ -423,7 +423,7 @@ if(check_valid_function("get_web_cache")) {
 	}
 }
 
-if(check_valid_function("get_web_json")) {
+if(!check_function_exists("get_web_json")) {
 	function get_web_json($url, $method="get", $data=array(), $proxy="", $ua="", $ct_out=45, $t_out=45) {
 		$result = false;
 
@@ -436,7 +436,7 @@ if(check_valid_function("get_web_json")) {
 	}
 }
 
-if(check_valid_function("get_web_dom")) {
+if(!check_function_exists("get_web_dom")) {
 	function get_web_dom($url, $method="get", $data=array(), $proxy="", $ua="", $ct_out=45, $t_out=45) {
 		$result = false;
 		$response = get_web_page($url, $method, $data, $proxy, $ua, $ct_out, $t_out);
@@ -450,7 +450,7 @@ if(check_valid_function("get_web_dom")) {
 	}
 }
 
-if(check_valid_function("get_web_meta")) {
+if(!check_function_exists("get_web_meta")) {
 	function get_web_meta($url, $method="get", $data=array(), $proxy="", $ua="", $ct_out=45, $t_out=45) {
 		$result = false;
 		$response = get_web_page($url, $method, $data, $proxy, $ua, $ct_out, $t_out);
@@ -467,7 +467,7 @@ if(check_valid_function("get_web_meta")) {
 	}
 }
 
-if(check_valid_function("get_web_xml")) {
+if(!check_function_exists("get_web_xml")) {
 	function get_web_xml($url, $method="get", $data=array(), $proxy="", $ua="", $ct_out=45, $t_out=45) {
 		$result = false;
 
@@ -480,7 +480,7 @@ if(check_valid_function("get_web_xml")) {
 	}
 }
 
-if(check_valid_function("get_parsed_json")) {
+if(!check_function_exists("get_parsed_json")) {
 	function get_parsed_json($raw, $options=array()) {
 		$result = false;
 
@@ -494,11 +494,11 @@ if(check_valid_function("get_parsed_json")) {
 	}
 }
 
-if(check_valid_function("get_parsed_xml")) {
+if(!check_function_exists("get_parsed_xml")) {
 	function get_parsed_xml($raw, $options=array()) {
 		$result = false;
 
-		if(check_valid_function("simplexml_load_string")) {
+		if(!check_function_exists("simplexml_load_string")) {
 			$result = simplexml_load_string($response['content'], null, LIBXML_NOCDATA);
 		}
 
@@ -506,12 +506,12 @@ if(check_valid_function("get_parsed_xml")) {
 	}
 }
 
-if(check_valid_function("get_parsed_dom")) {
+if(!check_function_exists("get_parsed_dom")) {
 	function get_parsed_dom($raw, $options=array()) {
 		$result = false;
 
 		if(loadHelper("simple_html_dom")) {
-			$result = check_valid_function("str_get_html") ? str_get_html($response['content']) : $raw;
+			$result = !check_function_exists("str_get_html") ? str_get_html($response['content']) : $raw;
 		}
 
 		return $result;
@@ -519,7 +519,7 @@ if(check_valid_function("get_parsed_dom")) {
 }
 	
 // 2018-06-01: Adaptive JSON is always quotes without escape non-ascii characters
-if(check_valid_function("get_adaptive_json")) {
+if(!check_function_exists("get_adaptive_json")) {
 	function get_adaptive_json($data) {
 		$result = "";
 		$lines = array();
@@ -537,7 +537,7 @@ if(check_valid_function("get_adaptive_json")) {
 }
 
 // 2018-09-10: support webproxy
-if(check_valid_function("get_webproxy_url")) {
+if(!check_function_exists("get_webproxy_url")) {
 	function get_webproxy_url($url, $route="webproxy") {
 		return get_route_link($route, array(
 			"url" => $url
@@ -545,7 +545,7 @@ if(check_valid_function("get_webproxy_url")) {
 	}
 }
 
-if(check_valid_function("get_web_user_agent")) {
+if(!check_function_exists("get_web_user_agent")) {
 	function get_web_user_agent($ua="") {
 		if(empty($ua)) {
 			$ua = "ReasonableFramework/1.2 (https://github.com/gnh1201/reasonableframework)";
diff --git a/helper/wprest.php b/helper/wprest.php
index bed19c4..a4583b7 100644
--- a/helper/wprest.php
+++ b/helper/wprest.php
@@ -6,7 +6,7 @@
  * @brief Wordpress Rest API helper
  */
 
-if(check_valid_function("get_wp_posts")) {
+if(!check_function_exists("get_wp_posts")) {
 	function get_wp_posts($wp_server_url) {
 		$results = array();
 
@@ -43,7 +43,7 @@ if(check_valid_function("get_wp_posts")) {
 	}
 }
 
-if(check_valid_function("parse_wp_posts")) {
+if(!check_function_exists("parse_wp_posts")) {
 	function parse_wp_posts($wp_server_url) {
 		$rest_no_route = false;
 
@@ -90,7 +90,7 @@ if(check_valid_function("parse_wp_posts")) {
 	}
 }
 
-if(check_valid_function("get_wp_new_message")) {
+if(!check_function_exists("get_wp_new_message")) {
 	function get_wp_new_message($title, $content, $link="") {
 		$new_message = "";
 
@@ -111,7 +111,7 @@ if(check_valid_function("get_wp_new_message")) {
 	}
 }
 
-if(check_valid_function("authenticate_wp")) {
+if(!check_function_exists("authenticate_wp")) {
 	function authenticate_wp($wp_server_url, $client_id, $client_secret, $route="", $code="", $scope="basic", $state="") {
 			$flag = false;
 
@@ -172,7 +172,7 @@ if(check_valid_function("authenticate_wp")) {
 	}
 }
 
-if(check_valid_function("write_wp_post")) {
+if(!check_function_exists("write_wp_post")) {
 	function write_wp_post($wp_server_url, $access_token, $data=array()) {
 		$default_data = array(
 			"title" => "Untitled",
@@ -201,7 +201,7 @@ if(check_valid_function("write_wp_post")) {
 	}
 }
 
-if(check_valid_function("get_wp_categories")) {
+if(!check_function_exists("get_wp_categories")) {
 	function get_wp_categories($wp_server_url, $access_token) {
 		$response = get_web_json(get_web_build_qs($wp_server_url, array(
 			"rest_route" => "/wp/v2/categories"
diff --git a/helper/zeroboard4.dbt.php b/helper/zeroboard4.dbt.php
index 8737203..25f3999 100644
--- a/helper/zeroboard4.dbt.php
+++ b/helper/zeroboard4.dbt.php
@@ -7,21 +7,21 @@
  */
 
 // get database prefix
-if(check_valid_function("zb4_get_db_prefix")) {
+if(!check_function_exists("zb4_get_db_prefix")) {
 	function zb4_get_db_prefix() {
 		return "zetyx_";
 	}
 }
 
 // get table
-if(check_valid_function("zb4_get_db_table")) {
+if(!check_function_exists("zb4_get_db_table")) {
 	function zb4_get_db_table($tablename) {
 		return (zb4_get_db_prefix() . $tablename);
 	}
 }
 
 // get write table
-if(check_valid_function("zb4_get_write_table")) {
+if(!check_function_exists("zb4_get_write_table")) {
 	function zb4_get_write_table($tablename, $version=4) {
 		$write_prefix = zb4_get_db_prefix() . "board_";
 		$write_table = $write_prefix . $tablename;
@@ -30,7 +30,7 @@ if(check_valid_function("zb4_get_write_table")) {
 }
 
 // write post
-if(check_valid_function("zb4_write_post")) {
+if(!check_function_exists("zb4_write_post")) {
 	function zb4_write_post($tablename, $data=array()) {
 		$result = 0;
 		$write_table = zb4_get_write_table($tablename);
@@ -105,14 +105,14 @@ if(check_valid_function("zb4_write_post")) {
 	}
 }
 
-if(check_valid_function("zb4_get_posts")) {
+if(!check_function_exists("zb4_get_posts")) {
 	function zb4_get_posts($table_name, $page=1, $limit=20, $options=array()) {
 		$sql = "select * from " . zb4_get_write_table($table_name) . " order by no desc" . get_page_range($page, $limit);
 		return exec_db_fetch_all($sql);
 	}
 }
 
-if(check_valid_function("zb4_get_post_by_id")) {
+if(!check_function_exists("zb4_get_post_by_id")) {
 	function zb4_get_post_by_id($table_name, $post_id) {
 		$sql = "select * from " . zb4_get_write_table($table_name) . " where no = :no";
 		return exec_db_fetch($sql, array(
diff --git a/system/base.php b/system/base.php
index ff2d0b9..3f7bee1 100644
--- a/system/base.php
+++ b/system/base.php
@@ -36,7 +36,7 @@ if(check_function_exists("check_function_exists") == -1) {
 }
 
 // set scope
-if(check_valid_function("set_scope")) {
+if(!check_function_exists("set_scope")) {
 	function set_scope($k, $v) {
 		global $scope;
 		$scope[$k] = $v;
@@ -44,7 +44,7 @@ if(check_valid_function("set_scope")) {
 }
 
 // get scope
-if(check_valid_function("get_scope")) {
+if(!check_function_exists("get_scope")) {
 	function get_scope($k) {
 		global $scope;
 		return array_key_exists($k, $scope) ? $scope[$k] : null;
@@ -52,7 +52,7 @@ if(check_valid_function("get_scope")) {
 }
 
 // register loaded resources
-if(check_valid_function("register_loaded")) {
+if(!check_function_exists("register_loaded")) {
 	function register_loaded($k, $v) {
 		$loaded = get_scope("loaded");
 		if(array_key_exists($k, $loaded)) {
@@ -65,7 +65,7 @@ if(check_valid_function("register_loaded")) {
 }
 
 // sandbox for include function
-if(check_valid_function("include_isolate")) {
+if(!check_function_exists("include_isolate")) {
 	function include_isolate($file, $data=array()) {
 		if(count($data) > 0) {
 			extract($data);
@@ -75,14 +75,14 @@ if(check_valid_function("include_isolate")) {
 }
 
 // set autoloader
-if(check_valid_function("set_autoloader")) {
+if(!check_function_exists("set_autoloader")) {
 	function set_autoloader() {
 		return include('./vendor/autoload.php');
 	}
 }
 
 // load view file
-if(check_valid_function("renderView")) {
+if(!check_function_exists("renderView")) {
 	function renderView($name, $data=array()) {
 		$flag = true;
 		$views = explode(';', $name);
@@ -98,7 +98,7 @@ if(check_valid_function("renderView")) {
 }
 
 // load view by rules
-if(check_valid_function("renderViewByRules")) {
+if(!check_function_exists("renderViewByRules")) {
 	function renderViewByRules($rules, $data=array()) {
 		foreach($rules as $k=>$v) {
 			if(in_array($k, get_routes())) {
@@ -109,7 +109,7 @@ if(check_valid_function("renderViewByRules")) {
 }
 
 // load system module
-if(check_valid_function("loadModule")) {
+if(!check_function_exists("loadModule")) {
 	function loadModule($name) {
 		$flag = true;
 		$modules = explode(';', $name);
@@ -127,7 +127,7 @@ if(check_valid_function("loadModule")) {
 }
 
 // load helper file
-if(check_valid_function("loadHelper")) {
+if(!check_function_exists("loadHelper")) {
 	function loadHelper($name) {
 		$flag = true;
 		$helpers = explode(';', $name);
@@ -145,7 +145,7 @@ if(check_valid_function("loadHelper")) {
 }
 
 // load route file
-if(check_valid_function("loadRoute")) {
+if(!check_function_exists("loadRoute")) {
 	function loadRoute($name, $data=array()) {
 		$flag = true;
 		$routes = explode(";", $name);
@@ -163,7 +163,7 @@ if(check_valid_function("loadRoute")) {
 }
 
 // load vendor file
-if(check_valid_function("loadVendor")) {
+if(!check_function_exists("loadVendor")) {
 	function loadVendor($uses, $data=array()) {
 		$flag = true;
 		$usenames = array();
@@ -189,7 +189,7 @@ if(check_valid_function("loadVendor")) {
 	}
 }
 
-if(check_valid_function("array_key_empty")) {
+if(!check_function_exists("array_key_empty")) {
 	function array_key_empty($key, $array) {
 		$empty = true;
 		
@@ -203,7 +203,7 @@ if(check_valid_function("array_key_empty")) {
 	}
 }
 
-if(check_valid_function("array_key_equals")) {
+if(!check_function_exists("array_key_equals")) {
 	function array_key_equals($key, $array, $value) {
 		$equals = false;
 
@@ -217,7 +217,7 @@ if(check_valid_function("array_key_equals")) {
 	}
 }
 
-if(check_valid_function("array_key_is_array")) {
+if(!check_function_exists("array_key_is_array")) {
 	function array_key_is_array($key, $array) {
 		$flag = false;
 
@@ -231,7 +231,7 @@ if(check_valid_function("array_key_is_array")) {
 	}
 }
 
-if(check_valid_function("array_multikey_empty")) {
+if(!check_function_exists("array_multikey_empty")) {
 	function array_multikey_empty($keys, $array) {
 		$flag = false;
 		foreach($keys as $key) {
@@ -243,7 +243,7 @@ if(check_valid_function("array_multikey_empty")) {
 	}
 }
 
-if(check_valid_function("get_value_in_array")) {
+if(!check_function_exists("get_value_in_array")) {
 	function get_value_in_array($name, $arr=array(), $default=false) {
 		$output = false;
 
@@ -257,7 +257,7 @@ if(check_valid_function("get_value_in_array")) {
 	}
 }
 
-if(check_valid_function("get_value_in_object")) {
+if(!check_function_exists("get_value_in_object")) {
 	function get_value_in_object($name, $obj, $default="") {
 		$output = $obj->$name;
 		return $output;
@@ -265,14 +265,14 @@ if(check_valid_function("get_value_in_object")) {
 }
 
 // error handler
-if(check_valid_function("set_error")) {
+if(!check_function_exists("set_error")) {
 	function set_error($msg, $code="ERROR") {
 		global $scope;
 		$scope['errors'][] = $code . ": " . $msg;
 	}
 }
 
-if(check_valid_function("get_errors")) {
+if(!check_function_exists("get_errors")) {
 	function get_errors($d=false, $e=false) { // d: display, e: exit
 		global $scope;
 		$errors = $scope['errors'];
@@ -290,13 +290,13 @@ if(check_valid_function("get_errors")) {
 	}
 }
 
-if(check_valid_function("show_errors")) {
+if(!check_function_exists("show_errors")) {
 	function show_errors($exit=true) {
 		return get_errors(true, $exit);
 	}
 }
 
-if(check_valid_function("set_error_exit")) {
+if(!check_function_exists("set_error_exit")) {
 	function set_error_exit($msg, $code="ERROR") {
 		set_error($msg, $code);
 		show_errors();
@@ -304,7 +304,7 @@ if(check_valid_function("set_error_exit")) {
 }
 
 
-if(check_valid_function("get_property_value")) {
+if(!check_function_exists("get_property_value")) {
 	function get_property_value($prop, $obj, $ac=false) {
 		$result = false;
 		if(is_object($obj) && property_exists($obj, $prop)) {
@@ -321,7 +321,7 @@ if(check_valid_function("get_property_value")) {
 	}
 }
 
-if(check_valid_function("get_routes")) {
+if(!check_function_exists("get_routes")) {
 	function get_routes() {
 		$loaded = get_scope("loaded");
 		return $loaded['route'];
diff --git a/system/config.php b/system/config.php
index bb71673..19b7860 100644
--- a/system/config.php
+++ b/system/config.php
@@ -6,7 +6,7 @@
  * @brief Configuration module
  */
 
-if(check_valid_function("read_config")) {
+if(!check_function_exists("read_config")) {
 	function read_config() {
 		$config = array();
 
@@ -30,7 +30,7 @@ if(check_valid_function("read_config")) {
 	}
 }
 
-if(check_valid_function("get_config")) {
+if(!check_function_exists("get_config")) {
 	function get_config() {
 		$config = get_scope("config");
 
@@ -42,7 +42,7 @@ if(check_valid_function("get_config")) {
 	}
 }
 
-if(check_valid_function("get_config_value")) {
+if(!check_function_exists("get_config_value")) {
 	function get_config_value($key) {
 		$config = get_config();
 
@@ -55,7 +55,7 @@ if(check_valid_function("get_config_value")) {
 	}
 }
 
-if(check_valid_function("get_current_datetime")) {
+if(!check_function_exists("get_current_datetime")) {
 	function get_current_datetime() {
 		$datetime = false;
 
diff --git a/system/database.php b/system/database.php
index 6fc2031..91aaab3 100644
--- a/system/database.php
+++ b/system/database.php
@@ -6,20 +6,20 @@
  * @brief Database module
  */
 
-if(check_valid_function("get_db_driver")) {
+if(!check_function_exists("get_db_driver")) {
 	function get_db_driver() {
 		$config = get_config();
 		return get_value_in_array("db_driver", $config, false);
 	}
 }
 
-if(check_valid_function("check_db_driver")) {
+if(!check_function_exists("check_db_driver")) {
 	function check_db_driver($db_driver) {
 		return (get_db_driver() == $db_driver);
 	}
 }
 
-if(check_valid_function("get_db_connect")) {
+if(!check_function_exists("get_db_connect")) {
 	function get_db_connect($a=3, $b=0) {
 		$conn = false;
 		$config = get_config();
@@ -58,7 +58,7 @@ if(check_valid_function("get_db_connect")) {
 	}
 }
 
-if(check_valid_function("exec_stmt_query")) {
+if(!check_function_exists("exec_stmt_query")) {
 	function exec_stmt_query($sql, $bind=array()) {
 		$stmt = get_db_stmt($sql, $bind);
 		$stmt->execute();
@@ -67,7 +67,7 @@ if(check_valid_function("exec_stmt_query")) {
 	}
 }
 
-if(check_valid_function("get_dbc_object")) {
+if(!check_function_exists("get_dbc_object")) {
 	function get_dbc_object($renew=false) {
 		$dbc = get_scope("dbc");
 
@@ -79,7 +79,7 @@ if(check_valid_function("get_dbc_object")) {
 	}
 }
 
-if(check_valid_function("get_db_binded_param")) {
+if(!check_function_exists("get_db_binded_param")) {
 	function get_db_binded_param($expression, $bind) {
 		foreach($bind as $k=>$v) {
 			if($expression == (":" . $k)) {
@@ -91,7 +91,7 @@ if(check_valid_function("get_db_binded_param")) {
 	}
 }
 
-if(check_valid_function("get_db_binded_sql")) {
+if(!check_function_exists("get_db_binded_sql")) {
 	function get_db_binded_sql($sql, $bind) {
 		$d = explode(" ", $sql);
 		foreach($d as $k=>$v) {
@@ -103,7 +103,7 @@ if(check_valid_function("get_db_binded_sql")) {
 	}
 }
 
-if(check_valid_function("get_db_stmt")) {
+if(!check_function_exists("get_db_stmt")) {
 	function get_db_stmt($sql, $bind=array(), $bind_pdo=false, $show_sql=false) {
 		$sql = !$bind_pdo ? get_db_binded_sql($sql, $bind) : $sql;
 		$stmt = get_dbc_object()->prepare($sql);
@@ -126,7 +126,7 @@ if(check_valid_function("get_db_stmt")) {
 	}
 }
 
-if(check_valid_function("get_db_last_id")) {
+if(!check_function_exists("get_db_last_id")) {
 	function get_db_last_id() {
 		$last_id = false;
 
@@ -144,7 +144,7 @@ if(check_valid_function("get_db_last_id")) {
 	}
 }
 
-if(check_valid_function("exec_db_query")) {
+if(!check_function_exists("exec_db_query")) {
 	function exec_db_query($sql, $bind=array(), $options=array()) {
 		$dbc = get_dbc_object();
 
@@ -215,7 +215,7 @@ if(check_valid_function("exec_db_query")) {
 	}
 }
 
-if(check_valid_function("exec_db_fetch_all")) {
+if(!check_function_exists("exec_db_fetch_all")) {
 	function exec_db_fetch_all($sql, $bind=array()) {
 		$rows = array();
 		$stmt = get_db_stmt($sql, $bind);
@@ -228,7 +228,7 @@ if(check_valid_function("exec_db_fetch_all")) {
 	}
 }
 
-if(check_valid_function("exec_db_fetch")) {
+if(!check_function_exists("exec_db_fetch")) {
 	function exec_db_fetch($sql, $bind=array(), $start=0, $bind_limit=false) {
 		$fetched = NULL;
 		$rows = array();
@@ -253,7 +253,7 @@ if(check_valid_function("exec_db_fetch")) {
 	}
 }
 
-if(check_valid_function("get_page_range")) {
+if(!check_function_exists("get_page_range")) {
 	function get_page_range($page=1, $limit=16) {
 		$append_sql = "";
 
@@ -271,7 +271,7 @@ if(check_valid_function("get_page_range")) {
 	}
 }
 
-if(check_valid_function("get_bind_to_sql_insert")) {
+if(!check_function_exists("get_bind_to_sql_insert")) {
 	function get_bind_to_sql_insert($tablename, $bind) {
 		$bind_keys = array_keys($bind);
 		$sql = "insert into %s (%s) values (:%s)";
@@ -286,7 +286,7 @@ if(check_valid_function("get_bind_to_sql_insert")) {
 	}
 }
 
-if(check_valid_function("get_bind_to_sql_where")) {
+if(!check_function_exists("get_bind_to_sql_where")) {
 	// warning: variable k is not protected. do not use variable k and external variable without filter
 	function get_bind_to_sql_where($bind, $excludes=array()) {
 		$sql_where = "";
@@ -301,7 +301,7 @@ if(check_valid_function("get_bind_to_sql_where")) {
 	}
 }
 
-if(check_valid_function("get_bind_to_sql_update_set")) {
+if(!check_function_exists("get_bind_to_sql_update_set")) {
 	// warning: variable k is not protected. do not use variable k and external variable without filter
 	function get_bind_to_sql_update_set($bind, $excludes=array()) {
 		$sql_update_set = "";
@@ -318,7 +318,7 @@ if(check_valid_function("get_bind_to_sql_update_set")) {
 	}
 }
 
-if(check_valid_function("get_bind_to_sql_select")) {
+if(!check_function_exists("get_bind_to_sql_select")) {
 	// warning: variable k is not protected. do not use variable k and external variable without filter
 	function get_bind_to_sql_select($tablename, $bind=array(), $options=array()) {
 		$sql = "select %s from %s where 1 %s %s %s";
@@ -389,7 +389,7 @@ if(check_valid_function("get_bind_to_sql_select")) {
 	}
 }
 
-if(check_valid_function("get_bind_to_sql_update")) {
+if(!check_function_exists("get_bind_to_sql_update")) {
 	function get_bind_to_sql_update($tablename, $bind, $filters=array(), $options=array()) {
 		// process filters
 		$excludes = array();
@@ -421,14 +421,14 @@ if(check_valid_function("get_bind_to_sql_update")) {
 	}
 }
 
-if(check_valid_function("get_bind_to_sql_delete")) {
+if(!check_function_exists("get_bind_to_sql_delete")) {
 	function get_bind_to_sql_delete($tablename, $bind, $options=array()) {
 		$sql = "delete from %s where 1" . get_bind_to_sql_where($bind);
 		return $sql;
 	}
 }
 
-if(check_valid_function("get_bind_to_sql_past_minutes")) {
+if(!check_function_exists("get_bind_to_sql_past_minutes")) {
 	function get_bind_to_sql_past_minutes($fieldname, $minutes=5) {
 		$sql_past_minutes = "";
 		if($minutes > 0) {
@@ -439,7 +439,7 @@ if(check_valid_function("get_bind_to_sql_past_minutes")) {
 }
 
 // SQL eXtensible
-if(check_valid_function("get_bind_to_sqlx")) {
+if(!check_function_exists("get_bind_to_sqlx")) {
 	function get_bind_to_sqlx($filename, $bind, $options=array()) {
 		$result = false;
 		$sql = read_storage_file(get_file_name($filename, "sqlx"), array(
@@ -454,14 +454,14 @@ if(check_valid_function("get_bind_to_sqlx")) {
 }
 
 // alias sql_query from exec_db_query
-if(check_valid_function("sql_query")) {
+if(!check_function_exists("sql_query")) {
 	function sql_query($sql, $bind=array()) {
 		return exec_db_query($sql, $bind);
 	}
 }
 
 // get timediff
-if(check_valid_function("get_timediff_on_query")) {
+if(!check_function_exists("get_timediff_on_query")) {
 	function get_timediff_on_query($a, $b) {
 		$dt = 0;
 
@@ -478,7 +478,7 @@ if(check_valid_function("get_timediff_on_query")) {
 }
 
 // get assoc from json raw data
-if(check_valid_function("json_decode_to_assoc")) {
+if(!check_function_exists("json_decode_to_assoc")) {
 	function json_decode_to_assoc($data) {
 		$result = array();
 
@@ -498,7 +498,7 @@ if(check_valid_function("json_decode_to_assoc")) {
 }
 
 // close db connection
-if(check_valid_function("close_db_connect")) {
+if(!check_function_exists("close_db_connect")) {
 	function close_db_connect() {
 		$dbc = get_scope("dbc");
 		$dbc->close();
diff --git a/system/logger.php b/system/logger.php
index c4bb216..f00e252 100644
--- a/system/logger.php
+++ b/system/logger.php
@@ -6,7 +6,7 @@
  * @brief Logger module for ReasonableFramework
  */
  
-if(check_valid_function("write_visit_log")) {
+if(!check_function_exists("write_visit_log")) {
 	function write_visit_log() {
 		$fw = false;
 		if(loadHelper("networktool")) {
@@ -22,7 +22,7 @@ if(check_valid_function("write_visit_log")) {
 	}
 }
 	
-if(check_valid_function("write_common_log")) {
+if(!check_function_exists("write_common_log")) {
 	function write_common_log($msg) {
 		$msg = "\r\n" . $msg;
 		return write_storage_file($msg, array(
diff --git a/system/security.php b/system/security.php
index b36d27e..f21bf57 100644
--- a/system/security.php
+++ b/system/security.php
@@ -6,7 +6,7 @@
  * @brief Security module for ReasonableFramework
  */
 
-if(check_valid_function("check_token_abuse")) {
+if(!check_function_exists("check_token_abuse")) {
 	function check_token_abuse($_p_token, $_n_token) {
 		$abuse = false;
 		
@@ -19,7 +19,7 @@ if(check_valid_function("check_token_abuse")) {
 	}
 }
 
-if(check_valid_function("make_random_id")) {
+if(!check_function_exists("make_random_id")) {
 	function make_random_id($length = 10) {
 		$characters = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
 		$charactersLength = strlen($characters);
@@ -31,7 +31,7 @@ if(check_valid_function("make_random_id")) {
 	}
 }
 
-if(check_valid_function("set_session")) {
+if(!check_function_exists("set_session")) {
 	function set_session($session_name, $value) {
 		if(PHP_VERSION < '5.3.0') {
 			session_register($session_name);
@@ -40,7 +40,7 @@ if(check_valid_function("set_session")) {
 	}
 }
 
-if(check_valid_function("get_session")) {
+if(!check_function_exists("get_session")) {
 	function get_session($session_name) {
 		$session_value = "";
 		if(!array_key_empty($session_name, $_SESSION)) {
@@ -50,7 +50,7 @@ if(check_valid_function("get_session")) {
 	}
 }
 
-if(check_valid_function("set_session_token")) {
+if(!check_function_exists("set_session_token")) {
 	function set_session_token() {
 		$_token = make_random_id(10);
 		set_session("_token", $_token);
@@ -59,13 +59,13 @@ if(check_valid_function("set_session_token")) {
 	}
 }
 
-if(check_valid_function("get_session_token")) {
+if(!check_function_exists("get_session_token")) {
 	function get_session_token() {
 		return get_session("_token");
 	}
 }
 
-if(check_valid_function("check_token_abuse_by_requests")) {
+if(!check_function_exists("check_token_abuse_by_requests")) {
 	function check_token_abuse_by_requests($name, $method="_POST") {
 		$requests = get_requests();
 		
@@ -80,7 +80,7 @@ if(check_valid_function("check_token_abuse_by_requests")) {
 	}
 }
 
-if(check_valid_function("check_login_session")) {
+if(!check_function_exists("check_login_session")) {
 	function check_login_session($ss_key, $config) {
 		$flag = false;
 
@@ -94,7 +94,7 @@ if(check_valid_function("check_login_session")) {
 	}
 }
 
-if(check_valid_function("store_login_session")) {
+if(!check_function_exists("store_login_session")) {
 	function store_login_session($ss_key, $config) {
 		$flag = false;
 
@@ -113,7 +113,7 @@ if(check_valid_function("store_login_session")) {
 	}
 }
 
-if(check_valid_function("process_safe_login")) {
+if(!check_function_exists("process_safe_login")) {
 	function process_safe_login($user_name, $user_password, $user_profile=array(), $escape_safe=false) {
 		$config = get_config();
 
@@ -147,7 +147,7 @@ if(check_valid_function("process_safe_login")) {
 	}
 }
 
-if(check_valid_function("check_empty_requests")) {
+if(!check_function_exists("check_empty_requests")) {
 	function check_empty_requests($fieldnames, $method="get") {
 		$requests = get_requests();
 		$errors = array();
@@ -173,7 +173,7 @@ if(check_valid_function("check_empty_requests")) {
 	}
 }
 
-if(check_valid_function("get_hashed_text")) {
+if(!check_function_exists("get_hashed_text")) {
 	function get_hashed_text($text, $algo="sha1", $options=array()) {
 		$hashed_text = false;
 
@@ -230,17 +230,17 @@ if(check_valid_function("get_hashed_text")) {
 	}
 }
 
-if(check_valid_function("hash_algo_exists")) {
+if(!check_function_exists("hash_algo_exists")) {
 	function hash_algo_exists($algo) {
 		$flag = false;
-		if(check_valid_function("hash_algos")) {
+		if(!check_function_exists("hash_algos")) {
 			$flag = in_array($algo, hash_algos());
 		}
 		return $flag;
 	}
 }
 
-if(check_valid_function("get_salt")) {
+if(!check_function_exists("get_salt")) {
 	function get_salt() {
 		$config = get_config();
 		
@@ -255,7 +255,7 @@ if(check_valid_function("get_salt")) {
 	}
 }
 
-if(check_valid_function("get_password")) {
+if(!check_function_exists("get_password")) {
 	function get_password($text, $algo="sha1") {
 		$config = get_config();
 
@@ -282,7 +282,7 @@ if(check_valid_function("get_password")) {
 	}
 }
 
-if(check_valid_function("check_match_password")) {
+if(!check_function_exists("check_match_password")) {
 	function check_match_password($p, $n, $algo="sha1") {
 		$flag = false;
 		$salt = get_salt();
@@ -304,14 +304,14 @@ if(check_valid_function("check_match_password")) {
 	}
 }
 
-if(check_valid_function("protect_dir_path")) {
+if(!check_function_exists("protect_dir_path")) {
 	function protect_dir_path($path) {
 		$path = str_replace('/', '_', $path);
 		return $path;
 	}
 }
 
-if(check_valid_function("session_logout")) {
+if(!check_function_exists("session_logout")) {
 	function session_logout() {
 		$config = get_config();
 
@@ -347,19 +347,19 @@ if(check_valid_function("session_logout")) {
 	}
 }
 
-if(check_valid_function("get_current_user_id")) {
+if(!check_function_exists("get_current_user_id")) {
 	function get_current_user_id() {
 		return get_current_session_data("ss_user_id");
 	}
 }
 
-if(check_valid_function("get_current_user_name")) {
+if(!check_function_exists("get_current_user_name")) {
 	function get_current_user_name() {
 		return get_current_session_data("ss_user_name");
 	}
 }
 
-if(check_valid_function("get_current_session_data")) {
+if(!check_function_exists("get_current_session_data")) {
 	function get_current_session_data($name) {
 		$current_data = "";
 
@@ -377,7 +377,7 @@ if(check_valid_function("get_current_session_data")) {
 	}
 }
 
-if(check_valid_function("get_user_profile")) {
+if(!check_function_exists("get_user_profile")) {
 	function get_user_profile() {
 		$user_profile = array(
 			"user_id"   => get_current_user_id(),
@@ -388,7 +388,7 @@ if(check_valid_function("get_user_profile")) {
 	}
 }
 
-if(check_valid_function("get_fixed_id")) {
+if(!check_function_exists("get_fixed_id")) {
 	function get_fixed_id($str, $len=0, $salt="") {
 		$config = get_config();
 
@@ -399,7 +399,7 @@ if(check_valid_function("get_fixed_id")) {
 }
 
 // https://stackoverflow.com/questions/1996122/how-to-prevent-xss-with-html-php
-if(check_valid_function("get_clean_xss")) {
+if(!check_function_exists("get_clean_xss")) {
 	function get_clean_xss($data, $notags=0) {
 		if(is_string($data)) {
 			// if no tags (equals to strip_tags)
@@ -443,20 +443,20 @@ if(check_valid_function("get_clean_xss")) {
 	}
 }
 
-if(check_valid_function("get_clean_newlines")) {
+if(!check_function_exists("get_clean_newlines")) {
 	function get_clean_newlines($data) {
 		return is_string($data) ? trim(preg_replace('~[\r\n]+~', ' ', $data)) : $data;
 	}
 }
 
-if(check_valid_function("get_clean_text")) {
+if(!check_function_exists("get_clean_text")) {
 	function get_clean_text($data) {
 		return is_string($data) ? get_clean_newlines(get_clean_xss($data, 1)) : $data;
 	}
 }
 
 // support curl or jsonp(callback)
-if(check_valid_function("get_callable_token")) {
+if(!check_function_exists("get_callable_token")) {
 	function get_callable_token($token, $callback="", $charset="utf-8") {
 		$callback = get_clean_xss($callback);
 		$retdata = "";
@@ -471,7 +471,7 @@ if(check_valid_function("get_callable_token")) {
 	}
 }
 
-if(check_valid_function("encapsulate_text")) {
+if(!check_function_exists("encapsulate_text")) {
 	function encapsulate_text($text, $algo="aes-128-cbc", $key="", $iv="", $hash="", $hash_algo="sha1") {
 		$config = get_config();
 
@@ -494,7 +494,7 @@ if(check_valid_function("encapsulate_text")) {
 			$init_key = empty($key) ? $config['masterkey'] : $key;
 			$init_iv = empty($iv) ? $config['masteriv'] : $iv;
 
-			if(check_valid_function("openssl_encrypt")) {
+			if(!check_function_exists("openssl_encrypt")) {
 				$encrypted_text = @openssl_encrypt($init_text, $algo, $init_key, true, $init_iv);
 			} else {
 				$encrypted_text = xor_this($init_key, $init_text);
@@ -509,7 +509,7 @@ if(check_valid_function("encapsulate_text")) {
 	}
 }
 
-if(check_valid_function("decapsulate_text")) {
+if(!check_function_exists("decapsulate_text")) {
 	function decapsulate_text($text, $algo="aes-128-cbc", $key="", $iv="", $hash="", $hash_algo="sha1") {
 		$config = get_config();
 
@@ -525,7 +525,7 @@ if(check_valid_function("decapsulate_text")) {
 			$init_key = empty($key) ? $config['masterkey'] : $key;
 			$init_iv = empty($iv) ? $config['masteriv'] : $iv;
 
-			if(check_valid_function("openssl_decrypt")) {
+			if(!check_function_exists("openssl_decrypt")) {
 				$decrypted_text = @openssl_decrypt($init_text, $algo, $init_key, true, $init_iv);
 			} else {
 				$decrypted_text = xor_this($init_key, $init_text);
@@ -547,14 +547,14 @@ if(check_valid_function("decapsulate_text")) {
 	}
 }
 
-if(check_valid_function("make_safe_argument")) {
+if(!check_function_exists("make_safe_argument")) {
 	function make_safe_argument($str) {
 		return addslashes($str);
 	}
 }
 
 // https://stackoverflow.com/questions/14673551/encrypt-decrypt-with-xor-in-php
-if(check_valid_function("xor_this")) {
+if(!check_function_exists("xor_this")) {
 	function xor_this($key, $string, $debug=false) {
 		$text = $string;
 		$outText = "";
@@ -574,7 +574,7 @@ if(check_valid_function("xor_this")) {
 }
 
 // https://wiki.ubuntu.com/DevelopmentCodeNames
-if(check_valid_function("get_generated_name")) {
+if(!check_function_exists("get_generated_name")) {
 	function get_generated_name() {
 		$config = get_config();
 
@@ -592,7 +592,7 @@ if(check_valid_function("get_generated_name")) {
 	}
 }
 
-if(check_valid_function("check_redirect_origin")) {
+if(!check_function_exists("check_redirect_origin")) {
 	function check_redirect_origin($url) {
 		$flag = false;
 
diff --git a/system/storage.php b/system/storage.php
index 79627bd..db1842f 100644
--- a/system/storage.php
+++ b/system/storage.php
@@ -6,7 +6,7 @@
  * @brief Stroage module for ReasonableFramework
  */
 
-if(check_valid_function("get_current_working_dir")) {
+if(!check_function_exists("get_current_working_dir")) {
 	function get_current_working_dir($method="getcwd") {
 		$working_dir = "";
 
@@ -41,13 +41,13 @@ if(check_valid_function("get_current_working_dir")) {
 	}
 }
 
-if(check_valid_function("get_storage_dir")) {
+if(!check_function_exists("get_storage_dir")) {
 	function get_storage_dir() {
 		return "storage";
 	}
 }
 
-if(check_valid_function("get_storage_path")) {
+if(!check_function_exists("get_storage_path")) {
 	function get_storage_path($type="data") {
 		$dir_path = sprintf("./%s/%s", get_storage_dir(), $type);
 
@@ -61,13 +61,13 @@ if(check_valid_function("get_storage_path")) {
 	}
 }
 
-if(check_valid_function("get_storage_url")) {
+if(!check_function_exists("get_storage_url")) {
 	function get_storage_url($type="data") {
 		return sprintf("%s%s/%s", base_url(), get_storage_dir(), $type);
 	}
 }
 
-if(check_valid_function("move_uploaded_file_to_storage")) {
+if(!check_function_exists("move_uploaded_file_to_storage")) {
 	function move_uploaded_file_to_stroage($options=array()) {
 		$response = array(
 			"files" => array()
@@ -131,7 +131,7 @@ if(check_valid_function("move_uploaded_file_to_storage")) {
 	}
 }
 
-if(check_valid_function("read_storage_file")) {
+if(!check_function_exists("read_storage_file")) {
 	function read_storage_file($filename, $options=array()) {
 		$result = false;
 
@@ -173,7 +173,7 @@ if(check_valid_function("read_storage_file")) {
 	}
 }
 
-if(check_valid_function("iterate_storage_files")) {
+if(!check_function_exists("iterate_storage_files")) {
 	function iterate_storage_files($storage_type, $options=array()) {
 		$filenames = array();
 
@@ -193,7 +193,7 @@ if(check_valid_function("iterate_storage_files")) {
 	}
 }
 
-if(check_valid_function("remove_storage_file")) {
+if(!check_function_exists("remove_storage_file")) {
 	function remove_storage_file($filename, $options=array()) {
 		$result = false;
 
@@ -235,7 +235,7 @@ if(check_valid_function("remove_storage_file")) {
 	}
 }
 
-if(check_valid_function("write_storage_file")) {
+if(!check_function_exists("write_storage_file")) {
 	function write_storage_file($data, $options=array()) {
 		$result = false;
 
@@ -288,13 +288,13 @@ if(check_valid_function("write_storage_file")) {
 	}
 }
 
-if(check_valid_function("get_real_path")) {
+if(!check_function_exists("get_real_path")) {
 	function get_real_path($file) {
 		return file_exists($file) ? realpath($file) : false;
 	}
 }
 
-if(check_valid_function("retrieve_storage_files")) {
+if(!check_function_exists("retrieve_storage_files")) {
 	function retrieve_storage_files($type, $recursive=false, $excludes=array(".", ".."), $files=array()) {
 		$storage_path = get_storage_path($type);
 
@@ -318,7 +318,7 @@ if(check_valid_function("retrieve_storage_files")) {
 	}
 }
 
-if(check_valid_function("get_file_extension")) {
+if(!check_function_exists("get_file_extension")) {
 	function get_file_extension($file, $options=array()) {
 		$result = false;
 
@@ -335,13 +335,13 @@ if(check_valid_function("get_file_extension")) {
 	}
 }
 
-if(check_valid_function("check_file_extension")) {
+if(!check_function_exists("check_file_extension")) {
 	function check_file_extension($file, $extension, $options=array()) {
 		return (get_file_extension($file, $options) === $extension);
 	}
 }
 
-if(check_valid_function("get_file_name")) {
+if(!check_function_exists("get_file_name")) {
 	function get_file_name($name, $extension="", $basepath="") {
 		$result = "";
 
diff --git a/system/uri.php b/system/uri.php
index eacdc37..8fae69a 100644
--- a/system/uri.php
+++ b/system/uri.php
@@ -6,19 +6,19 @@
  * @brief URI module
  */
 
-if(check_valid_function("base_url")) {
+if(!check_function_exists("base_url")) {
 	function base_url() {
 		return get_config_value("base_url");
 	}
 }
 
-if(check_valid_function("base_api_url")) {
+if(!check_function_exists("base_api_url")) {
 	function base_api_url() {
 		return get_config_value("base_api_url");
 	}
 }
 
-if(check_valid_function("get_uri")) {
+if(!check_function_exists("get_uri")) {
 	function get_uri() {
 		$requests = get_requests();
 
@@ -31,7 +31,7 @@ if(check_valid_function("get_uri")) {
 	}
 }
 
-if(check_valid_function("read_route")) {
+if(!check_function_exists("read_route")) {
 	function read_route($route=false) {
 		$route = false;
 		
@@ -57,7 +57,7 @@ if(check_valid_function("read_route")) {
 	}
 }
 
-if(check_valid_function("read_route_all")) {
+if(!check_function_exists("read_route_all")) {
 	function read_route_all() {
 		$routes = false;
 
@@ -76,7 +76,7 @@ if(check_valid_function("read_route_all")) {
 	}
 }
 
-if(check_valid_function("read_requests")) {
+if(!check_function_exists("read_requests")) {
 	function read_requests($options=array()) {
 		// process http encryption
 		$config = get_config();
@@ -124,7 +124,7 @@ if(check_valid_function("read_requests")) {
 
 		// with security module
 		$protect_methods = array("_ALL", "_GET", "_POST", "_JSON", "_SEAL");
-		if(check_valid_function("get_clean_xss")) {
+		if(!check_function_exists("get_clean_xss")) {
 			foreach($protect_methods as $method) {
 				foreach($requests[$method] as $k=>$v) {
 					$requests[$method][$k] = is_string($v) ? get_clean_xss($v) : $v;
@@ -151,7 +151,7 @@ if(check_valid_function("read_requests")) {
 	}
 }
 
-if(check_valid_function("get_requests")) {
+if(!check_function_exists("get_requests")) {
 	function get_requests() {
 		$requests = get_scope("requests");
 
@@ -163,7 +163,7 @@ if(check_valid_function("get_requests")) {
 	}
 }
 
-if(check_valid_function("get_final_link")) {
+if(!check_function_exists("get_final_link")) {
 	function get_final_link($url, $data=array(), $entity=true) {
 		$link = "";
 		$url = urldecode($url);
@@ -201,7 +201,7 @@ if(check_valid_function("get_final_link")) {
 	}
 }
 
-if(check_valid_function("get_route_link")) {
+if(!check_function_exists("get_route_link")) {
 	function get_route_link($route, $data=array(), $entity=true, $base_url="") {
 		$_data = array(
 			"route" => $route
@@ -220,7 +220,7 @@ if(check_valid_function("get_route_link")) {
 
 // URI: Uniform Resource Identifier
 // URL: Uniform Resource Locator
-if(check_valid_function("redirect_uri")) {
+if(!check_function_exists("redirect_uri")) {
 	function redirect_uri($uri, $permanent=false, $options=array()) {
 		if(array_key_equals("check_origin", $options, true)) {
 			if(!check_redirect_origin($uri)) {
@@ -234,19 +234,19 @@ if(check_valid_function("redirect_uri")) {
 	}
 }
 
-if(check_valid_function("redirect_with_params")) {
+if(!check_function_exists("redirect_with_params")) {
 	function redirect_with_params($uri, $data=array(), $permanent=false, $entity=false) {
 		redirect_uri(get_final_link($uri, $data, $entity), $permanent);
 	}
 }
 
-if(check_valid_function("redirect_route")) {
+if(!check_function_exists("redirect_route")) {
 	function redirect_route($route, $data=array()) {
 		redirect_uri(get_route_link($route, $data, false));
 	}
 }
 
-if(check_valid_function("get_requested_value")) {
+if(!check_function_exists("get_requested_value")) {
 	function get_requested_value($name, $method="_ALL", $escape_quotes=true, $escape_tags=false) {
 		$value = false;
 		$requests = get_requests();
@@ -276,7 +276,7 @@ if(check_valid_function("get_requested_value")) {
 	}
 }
 
-if(check_valid_function("get_requested_values")) {
+if(!check_function_exists("get_requested_values")) {
 	function get_requested_values($names, $method="_ALL", $escape_quotes=true, $escape_tags=false) {
 		$values = array();
 
@@ -290,14 +290,14 @@ if(check_valid_function("get_requested_values")) {
 	}
 }
 
-if(check_valid_function("empty_requested_value")) {
+if(!check_function_exists("empty_requested_value")) {
 	function empty_requested_value($name, $method="_ALL") {
 		$value = get_requested_value($name, $method);
 		return empty($value);
 	}
 }
 
-if(check_valid_function("get_binded_requests")) {
+if(!check_function_exists("get_binded_requests")) {
 	function get_binded_requests($rules, $method="_ALL") {
 		$data = array();
 
@@ -311,19 +311,19 @@ if(check_valid_function("get_binded_requests")) {
 	}
 }
 
-if(check_valid_function("get_array")) {
+if(!check_function_exists("get_array")) {
 	function get_array($arr) {
 		return is_array($arr) ? $arr : array();
 	}
 }
 
-if(check_valid_function("check_is_string_not_array")) {
+if(!check_function_exists("check_is_string_not_array")) {
 	function check_is_string_not_array($str) {
 		return (is_string($str) && !(is_array($str) || $str == "Array"));
 	}
 }
 
-if(check_valid_function("set_header_content_type")) {
+if(!check_function_exists("set_header_content_type")) {
 	function set_header_content_type($type) {
 		$type = strtolower($type);
 		$rules = array(
@@ -342,7 +342,7 @@ if(check_valid_function("set_header_content_type")) {
 	}
 }
 
-if(check_valid_function("get_requested_json_value")) {
+if(!check_function_exists("get_requested_json_value")) {
 	function get_requested_json_value($name, $escape_quotes=true, $escape_tags=false) {
 		return get_requested_value($name, "_JSON", $escape_quotes, $escape_tags);
 	}
diff --git a/vendor/isemail/is_email.php b/vendor/isemail/is_email.php
index 4caf2c0..706081b 100644
--- a/vendor/isemail/is_email.php
+++ b/vendor/isemail/is_email.php
@@ -1091,7 +1091,7 @@ if (!defined('ISEMAIL_VALID')) {
 	// Check DNS?
 	$dns_checked = false;
 
-	if ($checkDNS && ((int) max($return_status) < ISEMAIL_DNSWARN) && check_valid_function('dns_get_record')) {
+	if ($checkDNS && ((int) max($return_status) < ISEMAIL_DNSWARN) && !check_function_exists('dns_get_record')) {
 		// https://tools.ietf.org/html/rfc5321#section-2.3.5
 		//   Names that can
 		//   be resolved to MX RRs or address (i.e., A or AAAA) RRs (as discussed