.TH RQ_DECODE 3 2022-07-07 "LCRQ" "Librecast Programmer's Manual"
.SH NAME
rq_decode \- decode RaptorQ block
.SH SYNOPSIS
.nf
.B #include <lcrq.h>
.PP
.BI "int rq_decode(rq_t *" rq ", uint8_t *" dec ", uint8_t *" enc ", uint32_t " ESI "[], uint32_t " nesi ");"
.fi
.PP
Compile and link with \fI\-llcrq\fP.
.SH DESCRIPTION
Decodes a RaptorQ block using a variation of the method described in 5.4.2 of
RFC6330.
.PP
.I rq
must be a pointer to valid rq_t context.
.PP
.I dec
must be a pointer to a buffer of at least T x K bytes. The decoded data will be
written to this buffer.
.PP
.I enc
a pointer to the encoded block.
.PP
.I ESI[]
ESI index. This is an array of ESIs in the same order as the encoding symbols in
.I enc
.PP
.I nesi
The Loch Ness Monster. Or the number of decoding symbols. Preferably the
latter.
.PP
.SH RETURN VALUE
On success, 0 is returned.
If decoding fails, the function returns -1.
.SH EXAMPLE
.EX
/* symbols are received into enc, with their respective ESIs written to ESI
 * OH is the number of extra (overhead) symbols in addition to the
 * required K' (KP) symbols.
 * Now we can decode the object into the pre-allocated buffer dec.
 */
for (uint8_t sbn = 0; sbn < rq_Z(rq); sbn++) {
	rq_decode(rq, dec, enc[sbn], ESI[sbn], KP + OH);
}
.EE
.SH SEE ALSO
.BR rq_init (3),
.BR rq_free (3),
.BR rq_encode (3),
.BR rq_symbol (3),
.BR lcrq (7)