pack_bytes()

Generates a sequence of bytes by arranging element data.

Generates a sequence of bytes by arranging element data.

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

pack_bytes takes a begin(),end() iterator of the container class as a parameter and writes the data specified by the following parameters to the container as a sequence of bytes.

The data given for the variable argument parameters are as follows

Data Type	Number of 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 type uint8_t.
std::pair<char*,N>	N	A pair of an array of type char*,uint8_t* and array length. Can be generated with make_pair().

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

The pack_bytes takes a container object as a parameter and writes the data specified by the subsequent parameters as a sequence of bytes into the container. It is appended to the end by the container's .push_back() method.

The data given as variable argument parameters is shown below.

Data Type	Number of 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 type uint8_t.
std::pair<char*,N>	N	A pair of an array of type char*,uint8_t* and array length. Can be generated with make_pair().
smplbuf_u8?	.size()	smplbuf<>container of typeuint8_t. Container length (.size()`) of data.

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)	// seqence 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, each attribute and payload of the received packet is re-stored in a separate buffer buf.

Background

To simplify the description of byte arrays of type uint8_t used in the generation of data payloads and extraction of data in non-volatile packets.

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 byte arrays 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);
}