Function array_agg_array_deserialize

src/backend/utils/adt/array_userfuncs.c:1383–1466

}

Datum
array_agg_array_deserialize(PG_FUNCTION_ARGS)
{
	bytea	   *sstate;
	ArrayBuildStateArr *result;
	StringInfoData buf;
	Oid			element_type;
	Oid			array_type;
	int			nbytes;
	const char *temp;

	/* cannot be called directly because of internal-type argument */
	Assert(AggCheckCallContext(fcinfo, NULL));

	sstate = PG_GETARG_BYTEA_PP(0);

	/*
	 * Copy the bytea into a StringInfo so that we can "receive" it using the
	 * standard recv-function infrastructure.
	 */
	initStringInfo(&buf);
	appendBinaryStringInfo(&buf,
						   VARDATA_ANY(sstate), VARSIZE_ANY_EXHDR(sstate));

	/* element_type */
	element_type = pq_getmsgint(&buf, sizeof(Oid));

	/* array_type */
	array_type = pq_getmsgint(&buf, sizeof(Oid));

	/* nbytes */
	nbytes = pq_getmsgint(&buf, sizeof(int));

	result = initArrayResultArr(array_type, element_type,
								CurrentMemoryContext, false);

	result->abytes = 1024;
	while (result->abytes < nbytes)
		result->abytes *= 2;

	result->data = (char *) palloc(result->abytes);

	/* data */
	temp = pq_getmsgbytes(&buf, nbytes);
	memcpy(result->data, temp, nbytes);
	result->nbytes = nbytes;

	/* abytes */
	result->abytes = pq_getmsgint(&buf, sizeof(int));

	/* aitems: might be 0 */
	result->aitems = pq_getmsgint(&buf, sizeof(int));

	/* nullbitmap */
	if (result->aitems > 0)
	{
		int			size = (result->aitems + 7) / 8;