subsys/net/lib/lwm2m/README_lwm2m

LwM2M Client in Zephyr
----------------------

### SenML CBOR

SenML CBOR content format support takes advantage of the Zcbor library's capability of generating
domain specific code. To generate the SenML encoder and decoder the following CDDL file
is used as an input for the generator:

```
lwm2m_senml = [1* record]

record = {
	? bn => tstr,            ; Base Name
	? n => tstr,             ; Name
	? ( vi => int .size 8 // ; Integer Value
	    vf => float       // ; Float Value
	    vs => tstr        // ; String Value
	    vb => bool        // ; Boolean Value
	    vd => bstr ),        ; Data Value
	0*3 key-value-pair       ; To handle unordered maps; length-first ordered map keys
}

; now define the generic versions
key-value-pair = ( int => value )

value = tstr / bstr / int .size 8 / float / bool

n  = 0
bn = -2
vi = 2
vf = 2
vs = 3
vd = 8
vb = 4
```

The CDDL description is based on the RFC 8428 - Sensor Measurement Lists (SenML). For further
details please see the chapter 11 - CDDL.

To generate the encoder and decoder:

```console
zcbor --default-max-qty 99 -c CDDL_FILE code -e -t lwm2m_senml --oc lwm2m_senml_cbor_encode.c --oh lwm2m_senml_cbor_encode.h
zcbor --default-max-qty 99 -c CDDL_FILE code -d -t lwm2m_senml --oc lwm2m_senml_cbor_decode.c --oh lwm2m_senml_cbor_decode.h
```

The default value of the number of maximum allowed records doesn't really matter as it's replaced
with a Kconfig option.