src/linkgraph/refresh.h

   1 /* $Id: refresh.h 26283 2014-01-28 19:49:43Z fonsinchen $ */
   2
   3 /*
   4  * This file is part of OpenTTD.
   5  * OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
   6  * OpenTTD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
   7  * See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
   8  */
   9
  10 /** @file refresh.h Declaration of link refreshing utility. */
  11
  12 #ifndef REFRESH_H
  13 #define REFRESH_H
  14
  15 #include "../cargo_type.h"
  16 #include "../vehicle_base.h"
  17 #include "../3rdparty/cpp-btree/btree_set.h"
  18 #include <vector>
  19 #include <map>
  20
  21 /**
  22  * Utility to refresh links a consist will visit.
  23  */
  24 class LinkRefresher {
  25 public:
  26         static void Run(Vehicle *v, bool allow_merge = true, bool is_full_loading = false, uint32 cargo_mask = ~0);
  27
  28 protected:
  29         /**
  30          * Various flags about properties of the last examined link that might have
  31          * an influence on the next one.
  32          */
  33         enum RefreshFlags {
  34                 USE_NEXT,     ///< There was a conditional jump. Try to use the given next order when looking for a new one.
  35                 HAS_CARGO,    ///< Consist could leave the last stop where it could interact with cargo carrying cargo (i.e. not an "unload all" + "no loading" order).
  36                 WAS_REFIT,    ///< Consist was refit since the last stop where it could interact with cargo.
  37                 RESET_REFIT,  ///< Consist had a chance to load since the last refit and the refit capacities can be reset.
  38                 IN_AUTOREFIT, ///< Currently doing an autorefit loop. Ignore the first autorefit order.
  39         };
  40
  41         /**
  42          * Simulated cargo type and capacity for prediction of future links.
  43          */
  44         struct RefitDesc {
  45                 CargoID cargo;    ///< Cargo type the vehicle will be carrying.
  46                 uint16 capacity;  ///< Capacity the vehicle will have.
  47                 uint16 remaining; ///< Capacity remaining from before the previous refit.
  48                 RefitDesc(CargoID cargo, uint16 capacity, uint16 remaining) :
  49                                 cargo(cargo), capacity(capacity), remaining(remaining) {}
  50         };
  51
  52         /**
  53          * A hop the refresh algorithm might evaluate. If the same hop is seen again
  54          * the evaluation is stopped. This of course is a fairly simple heuristic.
  55          * Sequences of refit orders can produce vehicles with all kinds of
  56          * different cargoes and remembering only one can lead to early termination
  57          * of the algorithm. However, as the order language is Turing complete, we
  58          * are facing the halting problem here. At some point we have to draw the
  59          * line.
  60          */
  61         struct Hop {
  62                 OrderID from;  ///< Last order where vehicle could interact with cargo or absolute first order.
  63                 OrderID to;    ///< Next order to be processed.
  64                 CargoID cargo; ///< Cargo the consist is probably carrying or CT_INVALID if unknown.
  65
  66                 /**
  67                  * Default constructor should not be called but has to be visible for
  68                  * usage in btree::btree_set.
  69                  */
  70                 Hop() {}
  71
  72                 /**
  73                  * Real constructor, only use this one.
  74                  * @param from First order of the hop.
  75                  * @param to Second order of the hop.
  76                  * @param cargo Cargo the consist is probably carrying when passing the hop.
  77                  */
  78                 Hop(OrderID from, OrderID to, CargoID cargo) : from(from), to(to), cargo(cargo) {}
  79                 bool operator<(const Hop &other) const;
  80         };
  81
  82         typedef std::vector<RefitDesc> RefitList;
  83         typedef btree::btree_set<Hop> HopSet;
  84
  85         Vehicle *vehicle;           ///< Vehicle for which the links should be refreshed.
  86         uint capacities[NUM_CARGO]; ///< Current added capacities per cargo ID in the consist.
  87         RefitList refit_capacities; ///< Current state of capacity remaining from previous refits versus overall capacity per vehicle in the consist.
  88         HopSet *seen_hops;          ///< Hops already seen. If the same hop is seen twice we stop the algorithm. This is shared between all Refreshers of the same run.
  89         CargoID cargo;              ///< Cargo given in last refit order.
  90         bool allow_merge;           ///< If the refresher is allowed to merge or extend link graphs.
  91         bool is_full_loading;       ///< If the vehicle is full loading.
  92         uint32 cargo_mask;          ///< Bit-mask of cargo IDs to refresh.
  93
  94         LinkRefresher(Vehicle *v, HopSet *seen_hops, bool allow_merge, bool is_full_loading, uint32 cargo_mask);
  95
  96         bool HandleRefit(CargoID refit_cargo);
  97         void ResetRefit();
  98         void RefreshStats(const Order *cur, const Order *next);
  99         const Order *PredictNextOrder(const Order *cur, const Order *next, uint8 flags, uint num_hops = 0);
 100
 101         void RefreshLinks(const Order *cur, const Order *next, uint8 flags, uint num_hops = 0);
 102 };
 103
 104 #endif /* REFRESH_H */