Update getFileBlock

[fronders]

This addresses several things:

• fix %zu not supported by newlib's printf in Arduino_STM32 toolchain #38 by changing the format string to use %lu specifier which will work for everyone
• add more error checking and command formatting to make getFileBlock() similar to other methods
• make more reliable detection of comma_idx - the offset of file size in +URDBLOCK response

[PaulZC]

Hi @fronders ,

Thanks for submitting this.

Some compilers are 'fussy' and will throw an error on %lu if the type isn't 'long'. I'll run the compile-sketch test on it...

Cheers,
Paul

[PaulZC]

Yeah... %lu fails on ESP32:

It's messy, but you can fix this with a selective compile. Something like:

#ifdef ARDUINO_ARCH_ESP32 // ESP32 based boards
sprintf(command, "%s=\"%s\",%zu,%zu", SARA_R5_FILE_SYSTEM_READ_BLOCK, filename.c_str(), offset, requested_length);
#else
sprintf(command, "%s=\"%s\",%lu,%lu", SARA_R5_FILE_SYSTEM_READ_BLOCK, filename.c_str(), offset, requested_length);
#endif

[fronders]

@PaulZC I just noticed, that I forgot to add more error handling to response parser, hence the unused err variable. I'll get back when I have the code

[fronders]

@PaulZC I think using it with an explicit cast to unsigned long would be more universal than defining platform-dependant chunks:

// OK, yet insufficient with large sizes > ULONG_MAX
printf("%lu\n", (unsigned long) some_size_t_object); 

We should be fine with this for all 32-bit MCUs

Taken from here, what do you think?

[fronders]

@PaulZC just added that fix from code above that should work everywhere.

Also added error handling and response checks for getFileBlock() as it turns out it didn't have any before

[PaulZC]

Thanks @fronders ,

I'll give this another read through tomorrow, but all looks good...

Cheers,
Paul

[fronders]

hey @PaulZC, any updates? :)

[PaulZC]

Sorry @fronders - other stuff got in the way. I'll try and do this today. Please nudge me if I don't... Thanks!