Validate an option array

Question

We use the default WordPress register_setting() function to validate theme options. This call, for example:

register_setting( 'options-group', 'option1', 'intval' );

Will validate whether or not $option1 is an integer.

What can I use to pass an array of options to validate each member of the array?

For example:

$options = array(
    'options1' => 4,              // intval
    'options2' => '127.0.0.1',    // IP address
    'options3' => 'test@test.com' // Email address
);