Add SQLite3 database driver
diff --git a/system/database/drivers/sqlite3/sqlite3_forge.php b/system/database/drivers/sqlite3/sqlite3_forge.php
new file mode 100644
index 0000000..07c2551
--- /dev/null
+++ b/system/database/drivers/sqlite3/sqlite3_forge.php
@@ -0,0 +1,223 @@
+<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
+/**
+ * CodeIgniter
+ *
+ * An open source application development framework for PHP 5.1.6 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 1.0
+ * @filesource
+ */
+
+/**
+ * SQLite3 Forge Class
+ *
+ * @category	Database
+ * @author	Andrey Andreev
+ * @link	http://codeigniter.com/user_guide/database/
+ */
+class CI_DB_sqlite3_forge extends CI_DB_forge {
+
+	/**
+	 * Create database
+	 *
+	 * @param	string	the database name
+	 * @return	bool
+	 */
+	public function _create_database()
+	{
+		// In SQLite, a database is created when you connect to the database.
+		// We'll return TRUE so that an error isn't generated
+		return TRUE;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Drop database
+	 *
+	 * @param	string	the database name
+	 * @return	bool
+	 */
+	public function _drop_database($name)
+	{
+		// In SQLite, a database is dropped when we delete a file
+		if (@file_exists($this->db->database))
+		{
+			// We need to close the pseudo-connection first
+			$this->db->close();
+			if ( ! @unlink($this->db->database))
+			{
+				return $this->db->db_debug ? $this->db->display_error('db_unable_to_drop') : FALSE;
+			}
+
+			return TRUE;
+		}
+
+		return $this->db->db_debug ? $this->db->display_error('db_unable_to_drop') : FALSE;
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Create Table
+	 *
+	 * @param	string	the table name
+	 * @param	array	the fields
+	 * @param	mixed	primary key(s)
+	 * @param	mixed	key(s)
+	 * @param	bool	should 'IF NOT EXISTS' be added to the SQL
+	 * @return	bool
+	 */
+	public function _create_table($table, $fields, $primary_keys, $keys, $if_not_exists)
+	{
+		$sql = 'CREATE TABLE ';
+
+		// IF NOT EXISTS added to SQLite in 3.3.0
+		if ($if_not_exists === TRUE && version_compare($this->db->version(), '3.3.0', '>=') === TRUE)
+		{
+			$sql .= 'IF NOT EXISTS ';
+		}
+
+		$sql .= $this->db->_escape_identifiers($table).'(';
+		$current_field_count = 0;
+
+		foreach ($fields as $field=>$attributes)
+		{
+			// Numeric field names aren't allowed in databases, so if the key is
+			// numeric, we know it was assigned by PHP and the developer manually
+			// entered the field information, so we'll simply add it to the list
+			if (is_numeric($field))
+			{
+				$sql .= "\n\t".$attributes;
+			}
+			else
+			{
+				$attributes = array_change_key_case($attributes, CASE_UPPER);
+
+				$sql .= "\n\t".$this->db->_protect_identifiers($field)
+					.' '.$attributes['TYPE']
+					.(array_key_exists('CONSTRAINT', $attributes) ? '('.$attributes['CONSTRAINT'].')' : '')
+					.((array_key_exists('UNSIGNED', $attributes) && $attributes['UNSIGNED'] === TRUE) ? ' UNSIGNED' : '')
+					.(array_key_exists('DEFAULT', $attributes) ? ' DEFAULT \''.$attributes['DEFAULT'].'\'' : '')
+					.((array_key_exists('NULL', $attributes) && $attributes['NULL'] === TRUE) ? ' NULL' : ' NOT NULL')
+					.((array_key_exists('AUTO_INCREMENT', $attributes) && $attributes['AUTO_INCREMENT'] === TRUE) ? ' AUTO_INCREMENT' : '');
+			}
+
+			// don't add a comma on the end of the last field
+			if (++$current_field_count < count($fields))
+			{
+				$sql .= ',';
+			}
+		}
+
+		if (count($primary_keys) > 0)
+		{
+			$primary_keys = $this->db->_protect_identifiers($primary_keys);
+			$sql .= ",\n\tPRIMARY KEY (".implode(', ', $primary_keys).')';
+		}
+
+		if (is_array($keys) && count($keys) > 0)
+		{
+			foreach ($keys as $key)
+			{
+				if (is_array($key))
+				{
+					$key = $this->db->_protect_identifiers($key);
+				}
+				else
+				{
+					$key = array($this->db->_protect_identifiers($key));
+				}
+
+				$sql .= ",\n\tUNIQUE (".implode(', ', $key).')';
+			}
+		}
+
+		return $sql."\n)";
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Drop Table
+	 *
+	 * @param	string	the table name
+	 * @return	string
+	 */
+	public function _drop_table($table)
+	{
+		return 'DROP TABLE '.$table.' IF EXISTS';
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Alter table query
+	 *
+	 * Generates a platform-specific query so that a table can be altered
+	 * Called by add_column(), drop_column(), and column_alter(),
+	 *
+	 * @param	string	the ALTER type (ADD, DROP, CHANGE)
+	 * @param	string	the column name
+	 * @param	string	the table name
+	 * @param	string	the column definition
+	 * @param	string	the default value
+	 * @param	bool	should 'NOT NULL' be added
+	 * @param	string	the field after which we should add the new field
+	 * @return	string
+	 */
+	public function _alter_table($alter_type, $table, $column_name, $column_definition = '', $default_value = '', $null = '', $after_field = '')
+	{
+		/* SQLite only supports adding new columns and it does
+		 * NOT support the AFTER statement. Each new column will
+		 * be added as the last one in the table.
+		 */
+		if ($alter_type !== 'ADD COLUMN')
+		{
+			// Not supported
+			return FALSE;
+		}
+
+		return 'ALTER TABLE '.$this->db->_protect_identifiers($table).' '.$alter_type.' '.$this->db->_protect_identifiers($column_name)
+			.' '.$column_definition
+			.($default_value != '' ? ' DEFAULT '.$default_value : '')
+			// If NOT NULL is specified, the field must have a DEFAULT value other than NULL
+			.(($null !== NULL && $default_value !== 'NULL') ? ' NOT NULL' : ' NULL');
+	}
+
+	// --------------------------------------------------------------------
+
+	/**
+	 * Rename a table
+	 *
+	 * Generates a platform-specific query so that a table can be renamed
+	 *
+	 * @param	string	the old table name
+	 * @param	string	the new table name
+	 * @return	string
+	 */
+	public function _rename_table($table_name, $new_table_name)
+	{
+		return 'ALTER TABLE '.$this->db->_protect_identifiers($table_name).' RENAME TO '.$this->db->_protect_identifiers($new_table_name);
+	}
+}
+
+/* End of file sqlite3_forge.php */
+/* Location: ./system/database/drivers/sqlite3/sqlite3_forge.php */