Briefly, my Button class (yeah - I don't really like adding a capital C to a class name) maintains a state model to determine if changes on an input pin represent a click event, double click event, and so on, and call a C function to handle the appropriate event handler (onClick, onDoubleClick).
In the original code (OneButton) the CTOR takes a pin number - this is the Arduino pin and behind the scenes, the Arduino environment maps this into a port/pin combination during operations such as DigitalRead().
I want to do something similar - only I don't have Arduino pin numbers to play with (currently the code is targetted at ATTiny85 but it should work on any ATTiny or ATMega).
If I forget about specifying a port (after all, I can only use PORTB on an ATTiny85) I could pass just the port bit (for example, PB1) and hard code setting port direction (using the DDRB macro) and testing the input bit state - and this is what I will do for now.
I can define some constants representing the port number (and there are already macros for the bit numbers) and use a switch statement to determine which macro or inline assembly instruction to use - but this will require conditional code to determine whether the appropriate macro is available for the target platform.
I wondered if there is a generic solution to this problem - preferably one that doesn't have the code overhead of the Arduino.