.TH "RQ_PID2SBN" 3 2022-07-15 "LCRQ" "Librecast Programmer's Manual"
.SH NAME
rq_pid2sbn, rq_pid2esi, rq_pidsetsbn, rq_pidsetesi - get/set SBN,ESI in rq_pid_t
.SH SYNOPSIS
.nf
.B #include <lcrq.h>
.PP
.BI "uint8_t rq_pid2sbn(rq_pid_t " pid ");"
.BI "uint32_t rq_pid2esi(rq_pid_t " pid ");"
.BI "rq_pid_t rq_pidsetsbn(rq_pid_t " pid ", uint8_t " sbn ");"
.BI "rq_pid_t rq_pidsetesi(rq_pid_t " pid ", uint32_t " esi ");"
.fi
.PP
Compile and link with \fI\-llcrq\fP.
.SH DESCRIPTION
Bitshifting macros for getting and setting the SBN and ESI bits of rq_pid_t.
.PP
.EX
0                   1                   2                   3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|     SBN       |               Encoding Symbol ID              |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
.EE
.PP
SBN (Source Block Number) is an 8 bit unsigned integer. The Encoding Symbol ID
(ESI) is a 24 bit unsigned integer in network byte order.
.PP
.SH RETURN VALUE
.B rq_pid2sbn()
and
.B rq_pid2esi()
return the uint8_t SBN and uint32_t ESI numbers respectively.
.B rq_pidsetsbn()
and
.B rq_pidsetesi()
both return rq_pid_t with the appropriate bits set.
.SH ERRORS
These macros do not return errors.
.SH EXAMPLE
.SS Program source
\&
.EX
#include <assert.h>
#include <lcrq.h>

int main(void)
{
	rq_pid_t pid = 0;
	uint32_t esi = 19;
	uint8_t sbn = 42;

	/* set SBN and ESI bits */
	pid = rq_pidsetsbn(pid, sbn);
	pid = rq_pidsetesi(pid, esi);

	/* make sure we can read them back */
	assert(sbn == rq_pid2sbn(pid));
	assert(esi == rq_pid2esi(pid));

	return 0;
}
.EE
.SH SEE ALSO
.BR rq_init (3),
.BR rq_free (3),
.BR rq_decode (3),
.BR rq_encode (3),
.BR rq_symbol (3),
.BR lcrq (7)