Method get_slice

src/jrd/blb.cpp:870–960

SLONG blb::get_slice(thread_db* tdbb,
					jrd_tra* transaction,
					const bid* blob_id,
					const UCHAR* sdl,
					USHORT param_length,
					const UCHAR* param, SLONG slice_length, UCHAR* slice_addr)
{
/**************************************
 *
 *      b l b : : g e t _ s l i c e
 *
 **************************************
 *
 * Functional description
 *      Fetch a slice of an array.
 *
 **************************************/
	transaction = transaction->getOuter();

	SET_TDBB(tdbb);
    //Database* database = GET_DBB();
	Jrd::ContextPoolHolder context(tdbb, transaction->tra_pool);

	// Checkout slice description language
	SLONG variables[64];
	sdl_info info;
	memcpy(variables, param, MIN(sizeof(variables), param_length));

	if (SDL_info(tdbb->tdbb_status_vector, sdl, &info, variables)) {
		ERR_punt();
	}

	SLONG stuff[IAD_LEN(16) / 4];
	Ods::InternalArrayDesc* desc = (Ods::InternalArrayDesc*) stuff;
	blb* blob = get_array(tdbb, transaction, blob_id, desc);
	SLONG length = desc->iad_total_length;

	// Get someplace to put data

	UCharBuffer data_buffer;
	UCHAR* const data = data_buffer.getBuffer(desc->iad_total_length);

	// zero out memory, so that it does not have to be done for each element

	memset(data, 0, desc->iad_total_length);

	SLONG offset = 0;

	array_slice arg;

	// If we know something about the subscript bounds, prepare
	// to fetch only stuff we really care about

	if (info.sdl_info_dimensions)
	{
		const SLONG from = SDL_compute_subscript(tdbb->tdbb_status_vector, desc,
								  				 info.sdl_info_dimensions, info.sdl_info_lower);
		const SLONG to = SDL_compute_subscript(tdbb->tdbb_status_vector, desc,