Add pdo_firebird subdriver
diff --git a/system/database/drivers/pdo/pdo_driver.php b/system/database/drivers/pdo/pdo_driver.php
index 94a1210..b8724e9 100644
--- a/system/database/drivers/pdo/pdo_driver.php
+++ b/system/database/drivers/pdo/pdo_driver.php
@@ -143,7 +143,7 @@
 		}
 
 		// Add the database name to the DSN, if needed
-		if (stripos($this->dsn, 'dbname') === FALSE && in_array($this->subdriver, array('4D', 'firebird', 'cubrid')))
+		if (stripos($this->dsn, 'dbname') === FALSE && in_array($this->subdriver, array('4D', 'cubrid')))
 		{
 			$this->dsn .= 'dbname='.$this->database.';';
 		}
diff --git a/system/database/drivers/pdo/subdrivers/pdo_dblib_driver.php b/system/database/drivers/pdo/subdrivers/pdo_dblib_driver.php
index cee936a..0429207 100644
--- a/system/database/drivers/pdo/subdrivers/pdo_dblib_driver.php
+++ b/system/database/drivers/pdo/subdrivers/pdo_dblib_driver.php
@@ -73,7 +73,7 @@
 		}
 		else
 		{
-			if ( ! empty($this->char_set) && strpos($this->dsn, 'charset=') === FALSE)
+			if ( ! empty($this->char_set) && strpos($this->dsn, 'charset=', 6) === FALSE)
 			{
 				$this->dsn .= ';charset='.$this->char_set;
 			}
diff --git a/system/database/drivers/pdo/subdrivers/pdo_firebird_driver.php b/system/database/drivers/pdo/subdrivers/pdo_firebird_driver.php
new file mode 100644
index 0000000..c074a9a
--- /dev/null
+++ b/system/database/drivers/pdo/subdrivers/pdo_firebird_driver.php
@@ -0,0 +1,262 @@
+<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
+/**
+ * CodeIgniter
+ *
+ * An open source application development framework for PHP 5.2.4 or newer
+ *
+ * NOTICE OF LICENSE
+ *
+ * Licensed under the Open Software License version 3.0
+ *
+ * This source file is subject to the Open Software License (OSL 3.0) that is
+ * bundled with this package in the files license.txt / license.rst.  It is
+ * also available through the world wide web at this URL:
+ * http://opensource.org/licenses/OSL-3.0
+ * If you did not receive a copy of the license and are unable to obtain it
+ * through the world wide web, please send an email to
+ * licensing@ellislab.com so we can send you a copy immediately.
+ *
+ * @package		CodeIgniter
+ * @author		EllisLab Dev Team
+ * @copyright	Copyright (c) 2008 - 2012, EllisLab, Inc. (http://ellislab.com/)
+ * @license		http://opensource.org/licenses/OSL-3.0 Open Software License (OSL 3.0)
+ * @link		http://codeigniter.com
+ * @since		Version 3.0.0
+ * @filesource
+ */
+
+/**
+ * PDO Firebird Database Adapter Class
+ *
+ * Note: _DB is an extender class that the app controller
+ * creates dynamically based on whether the query builder
+ * class is being used or not.
+ *
+ * @package		CodeIgniter
+ * @subpackage	Drivers
+ * @category	Database
+ * @author		EllisLab Dev Team
+ * @link		http://codeigniter.com/user_guide/database/
+ */
+class CI_DB_pdo_firebird_driver extends CI_DB_pdo_driver {
+
+	public $subdriver = 'firebird';
+
+	/**
+	 * The syntax to count rows is slightly different across different
+	 * database engines, so this string appears in each driver and is
+	 * used for the count_all() and count_all_results() functions.
+	 */
+	protected $_random_keyword = ' RANDOM()'; // Currently not supported
+
+	/**
+	 * Constructor
+	 *
+	 * Builds the DSN if not already set.
+	 *
+	 * @param	array
+	 * @return	void
+	 */
+	public function __construct($params)
+	{
+		parent::__construct($params);
+
+		if (empty($this->dsn))
+		{
+			$this->dsn = 'firebird:';
+
+			if ( ! empty($this->database))
+			{
+				$this->dsn .= 'dbname='.$this->database;
+			}
+			elseif ( ! empty($this->hostname))
+			{
+				$this->dsn .= 'dbname='.$this->hostname;
+			}
+
+			empty($this->char_set) OR $this->dsn .= ';charset='.$this->char_set;
+			empty($this->role) OR $this->dsn .= ';role='.$this->role;
+		}
+		elseif ( ! empty($this->char_set) && strpos($this->dsn, 'charset=', 9) === FALSE)
+		{
+			$this->dsn .= ';charset='.$this->char_set;
+		}
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Show table query
+	 *
+	 * Generates a platform-specific query string so that the table names can be fetched
+	 *
+	 * @param	bool
+	 * @return	string
+	 */
+	protected function _list_tables($prefix_limit = FALSE)
+	{
+		$sql = 'SELECT "RDB$RELATION_NAME" FROM "RDB$RELATIONS" WHERE "RDB$RELATION_NAME" NOT LIKE \'RDB$%\' AND "RDB$RELATION_NAME" NOT LIKE \'MON$%\'';
+
+		if ($prefix_limit === TRUE && $this->dbprefix !== '')
+		{
+			return $sql.' AND "RDB$RELATION_NAME" LIKE \''.$this->escape_like_str($this->dbprefix)."%' "
+				.sprintf($this->_like_escape_str, $this->_like_escape_chr);
+		}
+
+		return $sql;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Show column query
+	 *
+	 * Generates a platform-specific query string so that the column names can be fetched
+	 *
+	 * @param	string	the table name
+	 * @return	string
+	 */
+	protected function _list_columns($table = '')
+	{
+		return 'SELECT "RDB$FIELD_NAME" FROM "RDB$RELATION_FIELDS" WHERE "RDB$RELATION_NAME" = '.$this->escape($table);
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Field data query
+	 *
+	 * Generates a platform-specific query so that the column data can be retrieved
+	 *
+	 * @param	string	the table name
+	 * @return	string
+	 */
+	protected function _field_data($table)
+	{
+		return 'SELECT FIRST 1 * FROM '.$this->protect_identifiers($table);
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * From Tables
+	 *
+	 * This function implicitly groups FROM tables so there is no confusion
+	 * about operator precedence in harmony with SQL standards
+	 *
+	 * @param	array
+	 * @return 	string
+	 */
+	protected function _from_tables($tables)
+	{
+		return is_array($tables) ? implode(', ', $tables) : $tables;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Update statement
+	 *
+	 * Generates a platform-specific update string from the supplied data
+	 *
+	 * @param	string	the table name
+	 * @param	array	the update data
+	 * @param	array	the where clause
+	 * @param	array	the orderby clause
+	 * @param	array	the limit clause (ignored)
+	 * @param	array	the like clause
+	 * @return	string
+	 */
+	protected function _update($table, $values, $where, $orderby = array(), $limit = FALSE, $like = array())
+	{
+		foreach ($values as $key => $val)
+		{
+			$valstr[] = $key.' = '.$val;
+		}
+
+		$where = empty($where) ? '' : ' WHERE '.implode(' ', $where);
+
+		if ( ! empty($like))
+		{
+			$where .= ($where === '' ? ' WHERE ' : ' AND ').implode(' ', $like);
+		}
+
+		return 'UPDATE '.$table.' SET '.implode(', ', $valstr)
+			.$where
+			.(count($orderby) > 0 ? ' ORDER BY '.implode(', ', $orderby) : '');
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Truncate statement
+	 *
+	 * Generates a platform-specific truncate string from the supplied data
+	 *
+	 * If the database does not support the truncate() command,
+	 * then this method maps to 'DELETE FROM table'
+	 *
+	 * @param	string	the table name
+	 * @return	string
+         */
+	protected function _truncate($table)
+	{
+		return 'DELETE FROM '.$table;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Delete statement
+	 *
+	 * Generates a platform-specific delete string from the supplied data
+	 *
+	 * @param	string	the table name
+	 * @param	array	the where clause
+	 * @param	array	the like clause
+	 * @param	string	the limit clause (ignored)
+	 * @return	string
+	 */
+	protected function _delete($table, $where = array(), $like = array(), $limit = FALSE)
+	{
+		$conditions = array();
+
+		empty($where) OR $conditions[] = implode(' ', $where);
+		empty($like) OR $conditions[] = implode(' ', $like);
+
+		return 'DELETE FROM '.$table.(count($conditions) > 0 ? ' WHERE '.implode(' AND ', $conditions) : '');
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Limit string
+	 *
+	 * Generates a platform-specific LIMIT clause
+	 *
+	 * @param	string	the sql query string
+	 * @param	int	the number of rows to limit the query to
+	 * @param	int	the offset value
+	 * @return	string
+	 */
+	protected function _limit($sql, $limit, $offset)
+	{
+		// Limit clause depends on if Interbase or Firebird
+		if (stripos($this->version(), 'firebird') !== FALSE)
+		{
+			$select = 'FIRST '. (int) $limit
+				.($offset > 0 ? ' SKIP '. (int) $offset : '');
+		}
+		else
+		{
+			$select = 'ROWS '
+				.($offset > 0 ? (int) $offset.' TO '.($limit + $offset) : (int) $limit);
+		}
+
+		return preg_replace('`SELECT`i', 'SELECT '.$select, $sql);
+	}
+
+}
+
+/* End of file pdo_firebird_driver.php */
+/* Location: ./system/database/drivers/pdo/subdrivers/pdo_firebird_driver.php */
\ No newline at end of file
diff --git a/system/database/drivers/pdo/subdrivers/pdo_mysql_driver.php b/system/database/drivers/pdo/subdrivers/pdo_mysql_driver.php
index be56212..dcab4ec 100644
--- a/system/database/drivers/pdo/subdrivers/pdo_mysql_driver.php
+++ b/system/database/drivers/pdo/subdrivers/pdo_mysql_driver.php
@@ -70,6 +70,10 @@
 			empty($this->database) OR $this->dsn .= ';dbname='.$this->database;
 			empty($this->char_set) OR $this->dsn .= ';charset='.$this->char_set;
 		}
+		elseif ( ! empty($this->char_set) && strpos($this->dsn, 'charset=', 6) === FALSE && is_php('5.3.6'))
+		{
+			$this->dsn .= ';charset='.$this->char_set;
+		}
 	}
 
 	// --------------------------------------------------------------------