Stream::find() not working for values above 0x7F

[pnjun]

I found out that the Stream::find() (and all related functions, findUntil() etc), does not work when the sequence to be found contains values above 0x7F. I believe this is because the function uses char instead of uint8_t.

Example, using these definitions:

char     a = 0xff;
uint8_t b = 0xff;

a == b is false, and therefore the find() method does not return a match when supplied a uint8_t[] array containing values above 0x7F, since the array gets casted to char. Changing the declaration of find() to uint8_t should solve the issue.

I don't know if ignoring values above 0x7F is the intended behaviour, but if that is the case I think the documentation should be more specific and explain this case better. In any case, if the current behaviour is the intended one, i do not see the reason behind it.

First time reporting something on Arduino, sorry if I overlooked something obvious.

[matthijskooijman]

Sounds like sloppy typing indeed, would be good to fix. I haven't looked closely, but I think that using char and char* in the public API is ok (since that's the common typing for a string), but internally, the code should make sure to either convert the target to uint8_t, or convert the thing to compare with to char too.

Did you try changing the typing to confirm that this indeeds fixes the problem?

Note that development on the non-arch-specific code happens at ArduinoCore-API repo now, so I'll transfer this issue there.