Function evlReverse

src/jrd/SysFunction.cpp:6381–6481

dsc* evlReverse(thread_db* tdbb, const SysFunction*, const NestValueArray& args,
	impure_value* impure)
{
	fb_assert(args.getCount() == 1);

	Request* request = tdbb->getRequest();

	dsc* value = EVL_expr(tdbb, request, args[0]);
	if (request->req_flags & req_null)	// return NULL if value is NULL
		return NULL;

	CharSet* cs = INTL_charset_lookup(tdbb, value->getCharSet());

	if (value->isBlob())
	{
		blb* blob = blb::open(tdbb, tdbb->getRequest()->req_transaction,
			reinterpret_cast<bid*>(value->dsc_address));

		HalfStaticArray<UCHAR, BUFFER_LARGE> buffer;
		HalfStaticArray<UCHAR, BUFFER_LARGE> buffer2;

		UCHAR* p = buffer.getBuffer(blob->blb_length);
		const SLONG len = blob->BLB_get_data(tdbb, p, blob->blb_length, true);

		if (cs->isMultiByte() || cs->minBytesPerChar() > 1)
		{
			const UCHAR* p1 = p;
			UCHAR* p2 = buffer2.getBuffer(len) + len;
			const UCHAR* const end = p1 + len;
			ULONG size = 0;

			while (p2 > buffer2.begin())
			{
#ifdef DEV_BUILD
				const bool read =
#endif
					IntlUtil::readOneChar(cs, &p1, end, &size);
				fb_assert(read == true);
				memcpy(p2 -= size, p1, size);
			}

			fb_assert(p2 == buffer2.begin());
			p = p2;
		}
		else
		{
			for (UCHAR* p2 = p + len - 1; p2 >= p; p++, p2--)
			{
				const UCHAR c = *p;
				*p = *p2;
				*p2 = c;
			}

			p = buffer.begin();
		}

		EVL_make_value(tdbb, value, impure);