diff --git a/_compile.php b/_compile.php
index b8976f5c..29118193 100644
--- a/_compile.php
+++ b/_compile.php
@@ -79,24 +79,33 @@ function php_shrink($input) {
 	$special_variables = array_flip(array('$TOKENS', '$this', '$GLOBALS', '$_GET', '$_POST', '$_FILES', '$_COOKIE', '$_SESSION', '$_SERVER'));
 	static $short_variables = array();
 	$shortening = true;
-	$special_functions = array_flip(array('Min_MySQLi', 'Min_MySQLResult', 'normalize_enum', '__construct'));
+	$special_functions = array_flip(array('Min_MySQLi', 'Min_MySQLResult', '__construct'));
+	$defined_functions = array();
 	static $short_functions = array();
 	$tokens = token_get_all($input);
 	
 	foreach ($tokens as $i => $token) {
 		if ($token[0] === T_VARIABLE && !isset($special_variables[$token[1]])) {
 			$short_variables[$token[1]]++;
-		} elseif ($token[0] === T_STRING && $tokens[$i+1] === '(' && !is_callable($token[1]) && !isset($special_functions[$token[1]])) {
+		} elseif ($token[0] === T_STRING && $tokens[$i+1] === '(' && !isset($special_functions[$token[1]])) {
 			$short_functions[$token[1]]++;
+			if ($tokens[$i-2][0] === T_FUNCTION) {
+				$defined_functions[$token[1]] = true;
+			}
 		}
 	}
+	
 	arsort($short_variables);
 	foreach (array_keys($short_variables) as $number => $key) {
 		$short_variables[$key] = short_identifier($number, implode("", range('a', 'z')) . '_' . implode("", range('A', 'Z'))); // could use also numbers and \x7f-\xff
 	}
 	arsort($short_functions);
-	foreach (array_keys($short_functions) as $number => $key) {
-		$short_functions[$key] = short_identifier($number, implode("", range('a', 'z')) . '_');
+	$number = 0;
+	foreach ($short_functions as $key => $val) {
+		if (isset($defined_functions[$key])) {
+			$short_functions[$key] = short_identifier($number, implode("", range('a', 'z')) . '_');
+			$number++;
+		}
 	}
 	
 	$set = array_flip(preg_split('//', '!"#$&\'()*+,-./:;<=>?@[\]^`{|}'));
@@ -117,11 +126,11 @@ function php_shrink($input) {
 				}
 			} elseif ($token[0] === T_VARIABLE && !isset($special_variables[$token[1]])) {
 				$token[1] = '$' . $short_variables[$token[1]];
-			} elseif ($token[0] === T_STRING && $tokens[$i+1] === '(' && !is_callable($token[1]) && !isset($special_functions[$token[1]])
+			} elseif ($token[0] === T_STRING && $tokens[$i+1] === '(' && isset($defined_functions[$token[1]])
 			&& $tokens[$i-1][0] !== T_DOUBLE_COLON && $tokens[$i-2][0] !== T_NEW && !in_array($tokens[$i-2][1], array('_result', '$_result'), true)
 			) {
 				$token[1] = $short_functions[$token[1]];
-			} elseif ($token[0] == T_CONSTANT_ENCAPSED_STRING && $tokens[$i-1] === '(' && in_array($tokens[$i-2][1], array('array_map', 'set_exception_handler'), true) && isset($short_functions[substr($token[1], 1, -1)])) {
+			} elseif ($token[0] == T_CONSTANT_ENCAPSED_STRING && (($tokens[$i-1] === '(' && in_array($tokens[$i-2][1], array('array_map', 'set_exception_handler'), true)) || $token[1] == "'normalize_enum'") && isset($defined_functions[substr($token[1], 1, -1)])) {
 				$token[1] = "'" . $short_functions[substr($token[1], 1, -1)] . "'";
 			}
 			if (isset($set[substr($output, -1)]) || isset($set[$token[1]{0}])) {
diff --git a/abstraction.inc.php b/abstraction.inc.php
index 24a9633b..3824e0d8 100644
--- a/abstraction.inc.php
+++ b/abstraction.inc.php
@@ -4,12 +4,12 @@ if (extension_loaded("mysqli")) {
 		var $extension = "MySQLi";
 		
 		function Min_MySQLi() {
-			parent::init();
+			$this->init();
 		}
 		
 		function connect($server, $username, $password) {
 			list($host, $port) = explode(":", $server, 2);
-			return @parent::real_connect(
+			return @$this->real_connect(
 				(strlen($server) ? $host : ini_get("mysqli.default_host")),
 				(strlen("$server$username") ? $username : ini_get("mysqli.default_user")),
 				(strlen("$server$username$password") ? $password : ini_get("mysqli.default_pw")),
@@ -181,7 +181,7 @@ if (extension_loaded("mysqli")) {
 			set_exception_handler('auth_error'); // try/catch is not compatible with PHP 4
 			parent::__construct("mysql:host=" . str_replace(":", ";port=", $server), $username, $password);
 			restore_exception_handler();
-			parent::setAttribute(13, array('Min_PDOStatement')); // PDO::ATTR_STATEMENT_CLASS
+			$this->setAttribute(13, array('Min_PDOStatement')); // PDO::ATTR_STATEMENT_CLASS
 			$this->server_info = $this->result($this->query("SELECT VERSION()"));
 			return true;
 		}
@@ -193,7 +193,7 @@ if (extension_loaded("mysqli")) {
 		function query($query) {
 			$_result = parent::query($query);
 			if (!$_result) {
-				$errorInfo = parent::errorInfo();
+				$errorInfo = $this->errorInfo();
 				$this->error = $errorInfo[2];
 				return false;
 			}
@@ -227,7 +227,7 @@ if (extension_loaded("mysqli")) {
 		}
 		
 		function escape_string($string) {
-			return substr(parent::quote($string), 1, -1);
+			return substr($this->quote($string), 1, -1);
 		}
 	}
 	
@@ -235,15 +235,15 @@ if (extension_loaded("mysqli")) {
 		var $_offset = 0, $num_rows;
 		
 		function fetch_assoc() {
-			return parent::fetch(2); // PDO::FETCH_ASSOC
+			return $this->fetch(2); // PDO::FETCH_ASSOC
 		}
 		
 		function fetch_row() {
-			return parent::fetch(3); // PDO::FETCH_NUM
+			return $this->fetch(3); // PDO::FETCH_NUM
 		}
 		
 		function fetch_field() {
-			$row = (object) parent::getColumnMeta($this->_offset++);
+			$row = (object) $this->getColumnMeta($this->_offset++);
 			$row->orgtable = $row->table;
 			$row->orgname = $row->name;
 			$row->charsetnr = (in_array("blob", $row->flags) ? 63 : 0);
diff --git a/todo.txt b/todo.txt
index c7568be2..e5e84070 100644
--- a/todo.txt
+++ b/todo.txt
@@ -10,3 +10,4 @@ Function to fix database encoding - http://php.vrana.cz/prevod-kodovani-mysql.ph
 ? Execution time in sql.inc.php
 ? Save token also to cookie - for session expiration and login in other window
 ? Save uploaded files after error to session variable instead of hidden field
+? Aliasing of built-in functions can save 7 KB, substitution of $_GET and friends can save 2 KB, remove of base64_decode() + using chars 127-255 in minification can save 1 KB