Count the number of byte in a multidimensional array

Having this array:

Array
(
    [_block1] => Array
        (
            [list] => Array
            (
                 [sub-list] => Array
                 (
                 )
            )
            [links] => Number
            [total] => Number
            ...
        )
    [_block2] => Array
        (
             [@attributes] => Array
             (
             )
             [title] => ...
             [data] => Array ()
             ...
        )
    [_block3] => Array
        (
             ..
        )
)

Those blocks contain data returned by api. Knowing that each api returns data in a different way/structure I need to measure/calculate the data/size inside of each and one of them and then do if data > X or < do something.

Is it possible? I have searched google but I only found count() and that isn't what I need to make this work.

Edit: Each and of the those blocks contain many other sub blocks, and I was thinking of calculating the data size in bytes, because count wont do the job here.

If I understood well your question, you need the size of each "block" subarray inside the main array.

You can do something like this:

$sizes = array();
foreach($returnedArray as $key => $content) {
    $sizes[$key] = count($content);
}

The $sizes array will be an associative array which the various "block"s as keys and the size of the data as values.

Edit: after the edit of the question, if the data inside the innermost arrays are strings or integers you can use a function like this:

function getSize($arr) {
    $tot = 0;
    foreach($arr as $a) {
        if (is_array($a)) {
            $tot += getSize($a);
        }
        if (is_string($a)) {
            $tot += strlen($a);
        }
        if (is_int($a)) {
            $tot += PHP_INT_SIZE;
        }
    }
    return $tot;
}

assuming to have only ASCII-encoded strings.