unaligned access exception

[szemzoa]

Hi,

First, thanks for your work!

I try to use the client on a cortex-m0+ SoC, and it works great with QOS0.
With QOS1 it throws an unaligned exception, in function

ssize_t mqtt_pack_pubxxx_request(uint8_t *buf, size_t bufsz,
enum MQTTControlPacketType control_type,
uint16_t packet_id)

when packed_id is casted at (uint16_t) buf = (uint16_t) MQTT_PAL_HTONS(packet_id);

It tries to write to address buf + 67 an uint16 packed_id variable, what is an unaligned exception on some arch.
So my proposal is to change ALL uint16_t casts to uint8_t buf to use memcpy, or use some kind of put_unaligned macros.

Regards,
Andras

[LiamBindle]

Hi Andras,

Sorry for the delayed response. Glad to hear that QoS 0 is working okay. It's always good to get feedback from different platforms!

Oh yeah, I see what you mean. That was a bit of an oversight.

I like your solution though, that seems like a good way to solve it to me. Another option that pops into my head is keeping track of the byte index and setting the byte array with |= rather than = with the desired value bit-shifted by the byte index mod platform integer size.

Either solution seems good to me though. I have a really busy month, so I probably won't have time to implement this until Christmas. If you or anyone else would like to implement it though, I'd be more than happy to merge a pull request 😄

Thanks for raising this!

Liam

[LiamBindle]

Sorry that closing this issue took so long. Again, thanks to @jepaan for the fix.