pack_bytes()

Generate a byte sequence by concatenating element data

Generates a byte sequence by concatenating element data.

uint8_t* pack_bytes(uint8_t* b, uint8_t* e, ...)

pack_bytes takes container class begin(), end() iterators as parameters and writes the data specified by the following parameters into the container as a byte sequence.

The data types given as variadic arguments are as follows.

Data Type	Bytes	Description
`uint8_t`	1
`uint16_t`	2	Stored in big-endian order
`uint32_t`	4	Stored in big-endian order
`uint8_t[N]`	N	Fixed-length array of `uint8_t`
`std::pair<char*,N>`	N	Pair of array and length for `char` or `uint8_t` arrays. Can be created with `make_pair()`.

smplbuf_u8& pack_bytes(smplbuf_u8& c, ...)

pack_bytes takes a container object as a parameter and writes the data specified by the following parameters into the container as a byte sequence. It appends to the end using the container’s .push_back() method.

The data types given as variadic arguments are as follows.

Data Type	Bytes	Description
`uint8_t`	1
`uint16_t`	2	Stored in big-endian order
`uint32_t`	4	Stored in big-endian order
`uint8_t[N]`	N	Fixed-length array of `uint8_t`
`std::pair<char*,N>`	N	Pair of array and length for `char` or `uint8_t` arrays. Can be created with `make_pair()`.
`smplbuf_u8?`	`.size()`	`smplbuf<>` container of `uint8_t` type. Stores data of container length (`.size()`).

Example

auto&& rx = the_twelite.receiver.read();

smplbuf<uint8_t, 128> buf;
mwx::pack_bytes(buf
	, uint8_t(rx.get_addr_src_lid())	// src addr (LID)
	, uint8_t(0xCC)							      // cmd id (0xCC, fixed)
	, uint8_t(rx.get_psRxDataApp()->u8Seq)	// sequence number
	, uint32_t(rx.get_addr_src_long())		// src addr (long)
	, uint32_t(rx.get_addr_dst())			// dst addr
	, uint8_t(rx.get_lqi())					  // LQI
	, uint16_t(rx.get_length())				// payload length
	, rx.get_payload() 						    // payload
);

In this example, attributes and payload of the received packet are re-stored into another buffer buf.

Background

To simplify the description of byte arrays of type uint8_t used for generating data payloads of wireless packets and extracting data.

auto&& rx = the_twelite.receiver.read();

uint8_t data[128];
data[0] = rx.get_addr_src_lid();
data[1] = 0xCC;
data[2] = rx.get_psRxDataApp()->u8Seq;
data[4] = rx.get_addr_src_long() & 0x000000FF;
data[5] = (rx.get_addr_src_long() & 0x0000FF00) >> 8;
data[6] = (rx.get_addr_src_long() & 0x00FF0000) >> 16;
data[7] = (rx.get_addr_src_long() & 0xFF000000) >> 24;
...

The above is the simplest description, but a byte array can be generated using Byte array utils as follows.

auto&& rx = the_twelite.receiver.read();

uint8_t data[128], *q = data;
S_OCTET(q, rx.get_addr_src_lid());
S_OCTET(q, 0xCC);
S_OCTET(q, rx.get_psRxDataApp()->u8Seq);
S_DWORD(q, rx.get_addr_src_long());
S_DWORD(q, rx.get_addr_dst());
S_OCTET(q, rx.get_lqi());
S_WORD(q, rx.get_length());
for (auto x : rx.get_payload()) {
  S_OCTET(q, x);
}