Method computeHash

src/jrd/recsrc/HashJoin.cpp:663–740

}

ULONG HashJoin::computeHash(thread_db* tdbb,
							Request* request,
						    const SubStream& sub,
							UCHAR* keyBuffer) const
{
	memset(keyBuffer, 0, sub.totalKeyLength);

	UCHAR* keyPtr = keyBuffer;

	for (FB_SIZE_T i = 0; i < sub.keys->getCount(); i++)
	{
		dsc* const desc = EVL_expr(tdbb, request, (*sub.keys)[i]);
		const USHORT keyLength = sub.keyLengths[i];

		if (desc && !(request->req_flags & req_null))
		{
			if (desc->isText())
			{
				dsc to;
				to.makeText(keyLength, desc->getTextType(), keyPtr);

				if (IS_INTL_DATA(desc))
				{
					// Convert the INTL string into the binary comparable form
					INTL_string_to_key(tdbb, INTL_INDEX_TYPE(desc),
									   desc, &to, INTL_KEY_UNIQUE);
				}
				else
				{
					// This call ensures that the padding bytes are appended
					MOV_move(tdbb, desc, &to);
				}
			}
			else
			{
				const auto data = desc->dsc_address;

				if (desc->isDecFloat())
				{
					// Values inside our key buffer are not aligned,
					// so ensure we satisfy our platform's alignment rules
					OutAligner<ULONG, MAX_DEC_KEY_LONGS> key(keyPtr, keyLength);

					if (desc->dsc_dtype == dtype_dec64)
						((Decimal64*) data)->makeKey(key);
					else if (desc->dsc_dtype == dtype_dec128)
						((Decimal128*) data)->makeKey(key);
					else
						fb_assert(false);
				}
				else if (desc->dsc_dtype == dtype_real && *(float*) data == 0)
				{
					fb_assert(keyLength == sizeof(float));
					memset(keyPtr, 0, keyLength); // positive zero in binary
				}
				else if (desc->dsc_dtype == dtype_double && *(double*) data == 0)
				{
					fb_assert(keyLength == sizeof(double));