Method Load

src/saveload/order_sl.cpp:164–214

	ORDRChunkHandler() : ChunkHandler('ORDR', CH_READONLY) {}

	void Load() const override
	{
		if (IsSavegameVersionBefore(SLV_5, 2)) {
			/* Version older than 5.2 did not have a ->next pointer. Convert them
			 * (in the old days, the orderlist was 5000 items big) */
			size_t len = SlGetFieldLength();

			if (IsSavegameVersionBefore(SLV_5)) {
				/* Pre-version 5 had another layout for orders
				 * (uint16_t instead of uint32_t) */
				len /= sizeof(uint16_t);
				std::vector<uint16_t> orders(len);

				SlCopy(&orders[0], len, SLE_UINT16);

				for (size_t i = 0; i < len; ++i) {
					auto &item = AllocateOldOrder(i);
					item.order.AssignOrder(UnpackVersion4Order(orders[i]));
				}
			} else if (IsSavegameVersionBefore(SLV_5, 2)) {
				len /= sizeof(uint32_t);
				std::vector<uint32_t> orders(len);

				SlCopy(&orders[0], len, SLE_UINT32);

				for (size_t i = 0; i < len; ++i) {
					auto &item = AllocateOldOrder(i);
					item.order = Order(GB(orders[i], 0, 8), GB(orders[i], 8, 8), GB(orders[i], 16, 16));
				}
			}

			/* Update all the next pointer. The orders were built like this:
			 * While the order is valid, the previous order will get its next pointer set */
			for (uint32_t num = 1; const OldOrderSaveLoadItem &item : _old_order_saveload_pool) {
				if (!item.order.IsType(OT_NOTHING) && num > 1) {
					OldOrderSaveLoadItem *prev = GetOldOrder(num - 1);
					if (prev != nullptr) prev->next = num;
				}
				++num;
			}
		} else {
			const std::vector<SaveLoad> slt = SlCompatTableHeader(GetOrderDescription(), _order_sl_compat);

			int index;

			while ((index = SlIterateArray()) != -1) {
				auto &item = AllocateOldOrder(index);
				SlObject(&item, slt);
			}
		}
	}
};

template <typename T>