Question

In Java, I can easily cast a number to a byte, for example:

System.err.println((byte) 13020);

the result will be

-36

Now how can I achieve the same in PHP?

Answer 1

Maybe do a modulo 256 expression (if unsigned) or modulo 256 and minus 128.

$val = ($val % 256) - 128

This work if you only want a value. If you want a real-one-byte, maybe pack() function will help here.

Edit: Right, 0 would be 128, so maybe this solution do will works:

$val = (($val+128) % 256) - 128