Bug fix for char and overflow

[tamtam22]

serialport_read_until() method needs some optimization, in particular these 2 fixes!

1. More proper way to declare char:

char b[1]; change to char b;
int n = read(fd, b, 1); change to int n = read(fd, &b, 1);
buf[i] = b[0]; change to buf[i] = b;
while( b[0] != until ... change to while( b != until ...

2. Overflow problem

while( ... && i < buf_max ... change to while( ... && i+1 < buf_max ...

Unless the documentation says that buf_max should be one less than the size of the buffer (which would be counterintuitive and error-prone)

Also, since i is checked at the end, even with this fix, the code will still store one byte if you pass in buf_max == 0 (but without the fix it will store two bytes). So that's another bug.

[todbot]

Awesome, thanks. If you submit a pull-request I'll merge it immediately.

[tamtam22]

Just a reminder the changes have been commited.

Hello,

I have found multiple fixes you have suggested for the Arduino Serial library.

He didn't commit anything in the code as I don't think he cares about this project.

This is pretty much the only existing C library out here to communicate with the Arduino so it worth fixing it.

I'm using this in various hobby projects and I experience a great deal of instability in the communication which is not the Arduinos fault because if I just open a regular screen /dev/ttyACM0 9600 and send a command with echo COMMAND > /dev/ttyACM0 it works fine roboustly.

However my code is a bit more complex. I basically put his library into a multi threaded socket server so an external app can connect with TELNET protocol on that C daemon and send a command such as LIGHTS_ON and that command will be relayed through serial to the Arduino then the response will come back and sent back through telnet. At least that would be the desired way...

I mostly have a problem with the read back function that I get junk like:

Desired line:
DEVICE,STATUS,14.93,0.96,11,20.31,08:56:43
Read back data:

 2020-05-01 14:13:08 ] From DEVICE (length: 22) [RAW]:
SA,NLN,49,.6,40.20:55

Which is junk. Can you maybe help me out with my code if you have some time?

I have already added your overflow modification it does not change my issues.

Thanks.