Function evlEncodeDecodeHex

src/jrd/SysFunction.cpp:3668–3769

}

dsc* evlEncodeDecodeHex(thread_db* tdbb, bool encodeFlag, const SysFunction* function, const NestValueArray& args, impure_value* impure)
{
	const dsc* arg = EVL_expr(tdbb, tdbb->getRequest(), args[0]);
	if (!arg)	// return NULL if value is NULL
		return NULL;

	const unsigned BLOB_BUF = 4096;
	UCHAR in[BLOB_BUF];
	const UCHAR* ptr;
	unsigned len = 0;
	HalfStaticArray<UCHAR, BLOB_BUF> out;
	UCHAR last;
	unsigned pos = 0;
	AutoPtr<blb> inBlob, outBlob;

	if (arg->isBlob())
	{
		// open all blobs as stream - that's perfectly OK for newly created blob with hex ascii
		// and enables exact restore of binary blob up to segmented structure if present
		inBlob.reset(blb::open2(tdbb, tdbb->getRequest()->req_transaction,
			reinterpret_cast<const bid*>(arg->dsc_address), sizeof(streamBpb), streamBpb));
		outBlob.reset(blb::create2(tdbb, tdbb->getRequest()->req_transaction,
			&impure->vlu_misc.vlu_bid, sizeof(streamBpb), streamBpb));
	}
	else
		ptr = CVT_get_bytes(arg, len);

	for(;; --len, ++pos)
	{
		if (arg->isBlob() && !len)
		{
			// try to get next portion of data from the blob
			len = inBlob->BLB_get_data(tdbb, in, sizeof in, false);
			ptr = in;
		}
		if (!len)
			break;

		UCHAR c = *ptr++;
		if (encodeFlag)
		{
			out.add(hexChar(c >> 4));
			out.add(hexChar(c));
		}
		else
		{
			if (pos & 1)
				out.add((last << 4) + binChar(c, pos));
			else
				last = binChar(c, pos);
		}

		if (out.getCount() >= BLOB_BUF && arg->isBlob())
		{
			outBlob->BLB_put_data(tdbb, out.begin(), out.getCount());
			out.clear();
		}
	}