linkgraph.cpp

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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 <https://www.gnu.org/licenses/old-licenses/gpl-2.0>.
 */

 
#include "../stdafx.h"
#include "../core/pool_func.hpp"
#include "linkgraph.h"
 
#include "../safeguards.h"
 
/* Initialize the link-graph-pool */
LinkGraphPool _link_graph_pool("LinkGraph");
INSTANTIATE_POOL_METHODS(LinkGraph)
 

LinkGraph::BaseNode::BaseNode(TileIndex xy, StationID st, uint demand)
{
  this->xy = xy;
  this->supply = 0;
  this->demand = demand;
  this->station = st;
  this->last_update = EconomyTime::INVALID_DATE;
}

LinkGraph::BaseEdge::BaseEdge(NodeID dest_node)
{
  this->capacity = 0;
  this->usage = 0;
  this->travel_time_sum = 0;
  this->last_unrestricted_update = EconomyTime::INVALID_DATE;
  this->last_restricted_update = EconomyTime::INVALID_DATE;
  this->dest_node = dest_node;
}

void LinkGraph::ShiftDates(TimerGameEconomy::Date interval)
{
  this->last_compression += interval;
  for (NodeID node1 = 0; node1 < this->Size(); ++node1) {
    BaseNode &source = this->nodes[node1];
    if (source.last_update != EconomyTime::INVALID_DATE) source.last_update += interval;
    for (BaseEdge &edge : this->nodes[node1].edges) {
      if (edge.last_unrestricted_update != EconomyTime::INVALID_DATE) edge.last_unrestricted_update += interval;
      if (edge.last_restricted_update != EconomyTime::INVALID_DATE) edge.last_restricted_update += interval;
    }
  }
}
 
void LinkGraph::Compress()
{
  this->last_compression = TimerGameEconomy::Date{(TimerGameEconomy::date + this->last_compression).base() / 2};
  for (NodeID node1 = 0; node1 < this->Size(); ++node1) {
    this->nodes[node1].supply /= 2;
    for (BaseEdge &edge : this->nodes[node1].edges) {
      if (edge.capacity > 0) {
        uint new_capacity = std::max(1U, edge.capacity / 2);
        if (edge.capacity < (1 << 16)) {
          edge.travel_time_sum = edge.travel_time_sum * new_capacity / edge.capacity;
        } else if (edge.travel_time_sum != 0) {
          edge.travel_time_sum = std::max<uint64_t>(1, edge.travel_time_sum / 2);
        }
        edge.capacity = new_capacity;
        edge.usage /= 2;
      }
    }
  }
}

void LinkGraph::Merge(LinkGraph *other)
{
  TimerGameEconomy::Date age = TimerGameEconomy::date - this->last_compression + 1;
  TimerGameEconomy::Date other_age = TimerGameEconomy::date - other->last_compression + 1;
  NodeID first = this->Size();
  for (NodeID node1 = 0; node1 < other->Size(); ++node1) {
    Station *st = Station::Get(other->nodes[node1].station);
    NodeID new_node = this->AddNode(st);
    this->nodes[new_node].supply = LinkGraph::Scale(other->nodes[node1].supply, age, other_age);
    st->goods[this->cargo].link_graph = this->index;
    st->goods[this->cargo].node = new_node;
 
    for (BaseEdge &e : other->nodes[node1].edges) {
      BaseEdge &new_edge = this->nodes[new_node].edges.emplace_back(first + e.dest_node);
      new_edge.capacity = LinkGraph::Scale(e.capacity, age, other_age);
      new_edge.usage = LinkGraph::Scale(e.usage, age, other_age);
      new_edge.travel_time_sum = LinkGraph::Scale(e.travel_time_sum, age, other_age);
    }
  }
  delete other;
}

void LinkGraph::RemoveNode(NodeID id)
{
  assert(id < this->Size());
 
  NodeID last_node = this->Size() - 1;
  Station::Get(this->nodes[last_node].station)->goods[this->cargo].node = id;
  /* Erase node by swapping with the last element. Node index is referenced
   * directly from station goods entries so the order and position must remain. */
  this->nodes[id] = this->nodes.back();
  this->nodes.pop_back();
  for (auto &n : this->nodes) {
    /* Find iterator position where an edge to id would be. */
    auto [first, last] = std::equal_range(n.edges.begin(), n.edges.end(), id);
    /* Remove potential node (erasing an empty range is safe). */
    auto insert = n.edges.erase(first, last);
    /* As the edge list is sorted, a potential edge to last_node will always be the last edge. */
    if (!n.edges.empty() && n.edges.back().dest_node == last_node) {
      /* Change dest ID and move into the spot of the deleted edge. */
      n.edges.back().dest_node = id;
      n.edges.insert(insert, n.edges.back());
      n.edges.pop_back();
    }
  }
}

NodeID LinkGraph::AddNode(const Station *st)
{
  const GoodsEntry &good = st->goods[this->cargo];
 
  NodeID new_node = this->Size();
  this->nodes.emplace_back(st->xy, st->index, good.status.Test(GoodsEntry::State::Acceptance));
 
  return new_node;
}

void LinkGraph::BaseNode::AddEdge(NodeID to, uint capacity, uint usage, uint32_t travel_time, EdgeUpdateModes modes)
{
  assert(!this->HasEdgeTo(to));
 
  BaseEdge &edge = *this->edges.emplace(std::upper_bound(this->edges.begin(), this->edges.end(), to), to);
  edge.capacity = capacity;
  edge.usage = usage;
  edge.travel_time_sum = static_cast<uint64_t>(travel_time) * capacity;
  if (modes.Test(EdgeUpdateMode::Unrestricted)) edge.last_unrestricted_update = TimerGameEconomy::date;
  if (modes.Test(EdgeUpdateMode::Restricted)) edge.last_restricted_update = TimerGameEconomy::date;
}

void LinkGraph::BaseNode::UpdateEdge(NodeID to, uint capacity, uint usage, uint32_t travel_time, EdgeUpdateModes modes)
{
  assert(capacity > 0);
  assert(usage <= capacity);
  if (!this->HasEdgeTo(to)) {
    this->AddEdge(to, capacity, usage, travel_time, modes);
  } else {
    this->GetEdge(to)->Update(capacity, usage, travel_time, modes);
  }
}

void LinkGraph::BaseNode::RemoveEdge(NodeID to)
{
  auto [first, last] = std::equal_range(this->edges.begin(), this->edges.end(), to);
  this->edges.erase(first, last);
}

void LinkGraph::BaseEdge::Update(uint capacity, uint usage, uint32_t travel_time, EdgeUpdateModes modes)
{
  assert(this->capacity > 0);
  assert(capacity >= usage);
 
  if (modes.Test(EdgeUpdateMode::Increase)) {
    if (this->travel_time_sum == 0) {
      this->travel_time_sum = static_cast<uint64_t>(this->capacity + capacity) * travel_time;
    } else if (travel_time == 0) {
      this->travel_time_sum += this->travel_time_sum / this->capacity * capacity;
    } else {
      this->travel_time_sum += static_cast<uint64_t>(travel_time) * capacity;
    }
    this->capacity += capacity;
    this->usage += usage;
  } else if (modes.Test(EdgeUpdateMode::Refresh)) {
    if (this->travel_time_sum == 0) {
      this->capacity = std::max(this->capacity, capacity);
      this->travel_time_sum = static_cast<uint64_t>(travel_time) * this->capacity;
    } else if (capacity > this->capacity) {
      this->travel_time_sum = this->travel_time_sum / this->capacity * capacity;
      this->capacity = capacity;
    }
    this->usage = std::max(this->usage, usage);
  }
  if (modes.Test(EdgeUpdateMode::Unrestricted)) this->last_unrestricted_update = TimerGameEconomy::date;
  if (modes.Test(EdgeUpdateMode::Restricted)) this->last_restricted_update = TimerGameEconomy::date;
}

void LinkGraph::Init(uint size)
{
  assert(this->Size() == 0);
  this->nodes.resize(size);
}