linkgraphjob.h

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/*
 * This file is part of OpenTTD.
 * 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.
 * 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.
 * 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/>.
 */
 
#ifndef LINKGRAPHJOB_H
#define LINKGRAPHJOB_H
 
#include "../thread.h"
#include "linkgraph.h"
#include <atomic>
 
class LinkGraphJob;
class Path;
typedef std::list<Path *> PathList;
 
typedef Pool<LinkGraphJob, LinkGraphJobID, 32, 0xFFFF> LinkGraphJobPool;
extern LinkGraphJobPool _link_graph_job_pool;
 
class LinkGraphJob : public LinkGraphJobPool::PoolItem<&_link_graph_job_pool>{
public:
  struct DemandAnnotation {
    uint demand;             
    uint unsatisfied_demand; 
  };
 
  struct EdgeAnnotation {
    const LinkGraph::BaseEdge &base; 
 
    uint flow;               
 
    EdgeAnnotation(const LinkGraph::BaseEdge &base) : base(base), flow(0) {}
 
    uint Flow() const { return this->flow; }
 
    void AddFlow(uint flow) { this->flow += flow; }
 
    void RemoveFlow(uint flow)
    {
      assert(flow <= this->flow);
      this->flow -= flow;
    }
 
    friend inline bool operator <(NodeID dest, const EdgeAnnotation &rhs)
    {
      return dest < rhs.base.dest_node;
    }
  };
 
  struct NodeAnnotation {
    const LinkGraph::BaseNode &base; 
 
    uint undelivered_supply; 
    PathList paths;          
    FlowStatMap flows;       
 
    std::vector<EdgeAnnotation>   edges;   
    std::vector<DemandAnnotation> demands; 
 
    NodeAnnotation(const LinkGraph::BaseNode &node, size_t size) : base(node), undelivered_supply(node.supply), paths(), flows()
    {
      this->edges.reserve(node.edges.size());
      for (auto &e : node.edges) this->edges.emplace_back(e);
      this->demands.resize(size);
    }
 
    EdgeAnnotation &operator[](NodeID to)
    {
      auto it = std::find_if(this->edges.begin(), this->edges.end(), [=] (const EdgeAnnotation &e) { return e.base.dest_node == to; });
      assert(it != this->edges.end());
      return *it;
    }
 
    const EdgeAnnotation &operator[](NodeID to) const
    {
      auto it = std::find_if(this->edges.begin(), this->edges.end(), [=] (const EdgeAnnotation &e) { return e.base.dest_node == to; });
      assert(it != this->edges.end());
      return *it;
    }
 
    uint DemandTo(NodeID to) const { return this->demands[to].demand; }
 
    uint UnsatisfiedDemandTo(NodeID to) const { return this->demands[to].unsatisfied_demand; }
 
    void SatisfyDemandTo(NodeID to, uint demand)
    {
      assert(demand <= this->demands[to].unsatisfied_demand);
      this->demands[to].unsatisfied_demand -= demand;
    }
 
    void DeliverSupply(NodeID to, uint amount)
    {
      this->undelivered_supply -= amount;
      this->demands[to].demand += amount;
      this->demands[to].unsatisfied_demand += amount;
    }
  };
 
private:
  typedef std::vector<NodeAnnotation> NodeAnnotationVector;
 
  friend SaveLoadTable GetLinkGraphJobDesc();
  friend class LinkGraphSchedule;
 
protected:
  const LinkGraph link_graph;        
  const LinkGraphSettings settings;  
  std::thread thread;                
  TimerGameEconomy::Date join_date; 
  NodeAnnotationVector nodes;        
  std::atomic<bool> job_completed;   
  std::atomic<bool> job_aborted;     
 
  void EraseFlows(NodeID from);
  void JoinThread();
  void SpawnThread();
 
public:
  LinkGraphJob() : settings(_settings_game.linkgraph),
      join_date(EconomyTime::INVALID_DATE), job_completed(false), job_aborted(false) {}
 
  LinkGraphJob(const LinkGraph &orig);
  ~LinkGraphJob();
 
  void Init();
 
  inline bool IsJobCompleted() const { return this->job_completed.load(std::memory_order_acquire); }
 
  inline bool IsJobAborted() const { return this->job_aborted.load(std::memory_order_acquire); }
 
  inline void AbortJob() { this->job_aborted.store(true, std::memory_order_release); }
 
  inline bool IsScheduledToBeJoined() const { return this->join_date <= TimerGameEconomy::date; }
 
  inline TimerGameEconomy::Date JoinDate() const { return join_date; }
 
  inline void ShiftJoinDate(TimerGameEconomy::Date interval) { this->join_date += interval; }
 
  inline const LinkGraphSettings &Settings() const { return this->settings; }
 
  inline NodeAnnotation &operator[](NodeID num) { return this->nodes[num]; }
 
  inline NodeID Size() const { return this->link_graph.Size(); }
 
  inline CargoID Cargo() const { return this->link_graph.Cargo(); }
 
  inline TimerGameEconomy::Date LastCompression() const { return this->link_graph.LastCompression(); }
 
  inline LinkGraphID LinkGraphIndex() const { return this->link_graph.index; }
 
  inline const LinkGraph &Graph() const { return this->link_graph; }
};
 
class Path {
public:
  static Path *invalid_path;
 
  Path(NodeID n, bool source = false);
  virtual ~Path() = default;
 
  inline NodeID GetNode() const { return this->node; }
 
  inline NodeID GetOrigin() const { return this->origin; }
 
  inline Path *GetParent() { return this->parent; }
 
  inline uint GetCapacity() const { return this->capacity; }
 
  inline int GetFreeCapacity() const { return this->free_capacity; }
 
  inline static int GetCapacityRatio(int free, uint total)
  {
    return Clamp(free, PATH_CAP_MIN_FREE, PATH_CAP_MAX_FREE) * PATH_CAP_MULTIPLIER / std::max(total, 1U);
  }
 
  inline int GetCapacityRatio() const
  {
    return Path::GetCapacityRatio(this->free_capacity, this->capacity);
  }
 
  inline uint GetDistance() const { return this->distance; }
 
  inline void ReduceFlow(uint f) { this->flow -= f; }
 
  inline void AddFlow(uint f) { this->flow += f; }
 
  inline uint GetFlow() const { return this->flow; }
 
  inline uint GetNumChildren() const { return this->num_children; }
 
  inline void Detach()
  {
    if (this->parent != nullptr) {
      this->parent->num_children--;
      this->parent = nullptr;
    }
  }
 
  uint AddFlow(uint f, LinkGraphJob &job, uint max_saturation);
  void Fork(Path *base, uint cap, int free_cap, uint dist);
 
protected:
 
  /*
   * Some boundaries to clamp against in order to avoid integer overflows.
   */
  static constexpr int PATH_CAP_MULTIPLIER = 16;
  static constexpr int PATH_CAP_MIN_FREE = (INT_MIN + 1) / PATH_CAP_MULTIPLIER;
  static constexpr int PATH_CAP_MAX_FREE = (INT_MAX - 1) / PATH_CAP_MULTIPLIER;
 
  uint distance;     
  uint capacity;     
  int free_capacity; 
  uint flow;         
  NodeID node;       
  NodeID origin;     
  uint num_children; 
  Path *parent;      
};
 
#endif /* LINKGRAPHJOB_H */