CI and Oracle: Escaping

[eluser]Unknown[/eluser]
There is a problem for the oci8 driver.
If called $db->escape() or $db->escape_str() - unary quotes aren't shielded.

Unary quotes escaping like (for oracle):

Code:

$str = str_replace("'", "''", $str);

Please fix

p.s. support of oracle in CI is realized badly