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Diffstat (limited to 'src/linkgraph/linkgraph.h')
| -rw-r--r-- | src/linkgraph/linkgraph.h | 516 |
1 files changed, 516 insertions, 0 deletions
diff --git a/src/linkgraph/linkgraph.h b/src/linkgraph/linkgraph.h new file mode 100644 index 000000000..8dfe3f8ea --- /dev/null +++ b/src/linkgraph/linkgraph.h @@ -0,0 +1,516 @@ +/* $Id$ */ + +/* + * 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/>. + */ + +/** @file linkgraph.h Declaration of link graph classes used for cargo distribution. */ + +#ifndef LINKGRAPH_H +#define LINKGRAPH_H + +#include "../core/pool_type.hpp" +#include "../core/smallmap_type.hpp" +#include "../core/smallmatrix_type.hpp" +#include "../station_base.h" +#include "../cargotype.h" +#include "../date_func.h" +#include "linkgraph_type.h" + +struct SaveLoad; +class LinkGraph; + +/** + * Type of the pool for link graph components. Each station can be in at up to + * 32 link graphs. So we allow for plenty of them to be created. + */ +typedef Pool<LinkGraph, LinkGraphID, 32, 0xFFFFFF> LinkGraphPool; +/** The actual pool with link graphs. */ +extern LinkGraphPool _link_graph_pool; + +/** + * A connected component of a link graph. Contains a complete set of stations + * connected by links as nodes and edges. Each component also holds a copy of + * the link graph settings at the time of its creation. The global settings + * might change between the creation and join time so we can't rely on them. + */ +class LinkGraph : public LinkGraphPool::PoolItem<&_link_graph_pool> { +public: + + /** + * Node of the link graph. contains all relevant information from the associated + * station. It's copied so that the link graph job can work on its own data set + * in a separate thread. + */ + struct BaseNode { + uint supply; ///< Supply at the station. + uint demand; ///< Acceptance at the station. + StationID station; ///< Station ID. + Date last_update; ///< When the supply was last updated. + void Init(StationID st = INVALID_STATION, uint demand = 0); + }; + + /** + * An edge in the link graph. Corresponds to a link between two stations or at + * least the distance between them. Edges from one node to itself contain the + * ID of the opposite Node of the first active edge (i.e. not just distance) in + * the column as next_edge. + */ + struct BaseEdge { + uint distance; ///< Length of the link. + uint capacity; ///< Capacity of the link. + uint usage; ///< Usage of the link. + Date last_update; ///< When the link was last updated. + NodeID next_edge; ///< Destination of next valid edge starting at the same source node. + void Init(uint distance = 0); + }; + + /** + * Wrapper for an edge (const or not) allowing retrieval, but no modification. + * @tparam Tedge Actual edge class, may be "const BaseEdge" or just "BaseEdge". + */ + template<typename Tedge> + class EdgeWrapper { + protected: + Tedge &edge; ///< Actual edge to be used. + + public: + + /** + * Wrap a an edge. + * @param edge Edge to be wrapped. + */ + EdgeWrapper (Tedge &edge) : edge(edge) {} + + /** + * Get edge's capacity. + * @return Capacity. + */ + uint Capacity() const { return this->edge.capacity; } + + /** + * Get edge's usage. + * @return Usage. + */ + uint Usage() const { return this->edge.usage; } + + /** + * Get edge's distance. + * @return Distance. + */ + uint Distance() const { return this->edge.distance; } + + /** + * Get edge's last update. + * @return Last update. + */ + Date LastUpdate() const { return this->edge.last_update; } + }; + + /** + * Wrapper for a node (const or not) allowing retrieval, but no modification. + * @tparam Tedge Actual node class, may be "const BaseNode" or just "BaseNode". + * @tparam Tedge Actual edge class, may be "const BaseEdge" or just "BaseEdge". + */ + template<typename Tnode, typename Tedge> + class NodeWrapper { + protected: + Tnode &node; ///< Node being wrapped. + Tedge *edges; ///< Outgoing edges for wrapped node. + NodeID index; ///< ID of wrapped node. + + public: + + /** + * Wrap a node. + * @param node Node to be wrapped. + * @param edges Outgoing edges for node to be wrapped. + * @param index ID of node to be wrapped. + */ + NodeWrapper(Tnode &node, Tedge *edges, NodeID index) : node(node), + edges(edges), index(index) {} + + /** + * Get supply of wrapped node. + * @return Supply. + */ + uint Supply() const { return this->node.supply; } + + /** + * Get demand of wrapped node. + * @return Demand. + */ + uint Demand() const { return this->node.demand; } + + /** + * Get ID of station belonging to wrapped node. + * @return ID of node's station. + */ + StationID Station() const { return this->node.station; } + + /** + * Get node's last update. + * @return Last update. + */ + Date LastUpdate() const { return this->node.last_update; } + }; + + /** + * Base class for iterating across outgoing edges of a node. Only the real + * edges (those with capacity) are iterated. The ones with only distance + * information are skipped. + * @tparam Tedge Actual edge class. May be "BaseEdge" or "const BaseEdge". + * @tparam Titer Actual iterator class. + */ + template <class Tedge, class Tedge_wrapper, class Titer> + class BaseEdgeIterator { + protected: + Tedge *base; ///< Array of edges being iterated. + NodeID current; ///< Current offset in edges array. + + /** + * A "fake" pointer to enable operator-> on temporaries. As the objects + * returned from operator* aren't references but real objects, we have + * to return something that implements operator->, but isn't a pointer + * from operator->. A fake pointer. + */ + class FakePointer : public SmallPair<NodeID, Tedge_wrapper> { + public: + + /** + * Construct a fake pointer from a pair of NodeID and edge. + * @param pair Pair to be "pointed" to (in fact shallow-copied). + */ + FakePointer(const SmallPair<NodeID, Tedge_wrapper> &pair) : SmallPair<NodeID, Tedge_wrapper>(pair) {} + + /** + * Retrieve the pair by operator->. + * @return Pair being "pointed" to. + */ + SmallPair<NodeID, Tedge_wrapper> *operator->() { return this; } + }; + + public: + /** + * Constructor. + * @param base Array of edges to be iterated. + * @param current ID of current node (to locate the first edge). + */ + BaseEdgeIterator (Tedge *base, NodeID current) : + base(base), + current(current == INVALID_NODE ? current : base[current].next_edge) + {} + + /** + * Prefix-increment. + * @return This. + */ + Titer &operator++() + { + this->current = this->base[this->current].next_edge; + return static_cast<Titer &>(*this); + } + + /** + * Postfix-increment. + * @return Version of this before increment. + */ + Titer operator++(int) + { + Titer ret(static_cast<Titer &>(*this)); + this->current = this->base[this->current].next_edge; + return ret; + } + + /** + * Compare with some other edge iterator. The other one may be of a + * child class. + * @tparam Tother Class of other iterator. + * @param other Instance of other iterator. + * @return If the iterators have the same edge array and current node. + */ + template<class Tother> + bool operator==(const Tother &other) + { + return this->base == other.base && this->current == other.current; + } + + /** + * Compare for inequality with some other edge iterator. The other one + * may be of a child class. + * @tparam Tother Class of other iterator. + * @param other Instance of other iterator. + * @return If either the edge arrays or the current nodes differ. + */ + template<class Tother> + bool operator!=(const Tother &other) + { + return this->base != other.base || this->current != other.current; + } + + /** + * Dereference with operator*. + * @return Pair of current target NodeID and edge object. + */ + SmallPair<NodeID, Tedge_wrapper> operator*() const + { + return SmallPair<NodeID, Tedge_wrapper>(this->current, Tedge_wrapper(this->base[this->current])); + } + + /** + * Dereference with operator->. + * @return Fake pointer to Pair of current target NodeID and edge object. + */ + FakePointer operator->() const { + return FakePointer(this->operator*()); + } + }; + + /** + * A constant edge class. + */ + typedef EdgeWrapper<const BaseEdge> ConstEdge; + + /** + * An updatable edge class. + */ + class Edge : public EdgeWrapper<BaseEdge> { + public: + /** + * Constructor + * @param edge Edge to be wrapped. + */ + Edge(BaseEdge &edge) : EdgeWrapper<BaseEdge>(edge) {} + void Update(uint capacity, uint usage); + }; + + /** + * An iterator for const edges. Cannot be typedef'ed because of + * template-reference to ConstEdgeIterator itself. + */ + class ConstEdgeIterator : public BaseEdgeIterator<const BaseEdge, ConstEdge, ConstEdgeIterator> { + public: + /** + * Constructor. + * @param edges Array of edges to be iterated over. + * @param current ID of current edge's end node. + */ + ConstEdgeIterator(const BaseEdge *edges, NodeID current) : + BaseEdgeIterator<const BaseEdge, ConstEdge, ConstEdgeIterator>(edges, current) {} + }; + + /** + * An iterator for non-const edges. Cannot be typedef'ed because of + * template-reference to EdgeIterator itself. + */ + class EdgeIterator : public BaseEdgeIterator<BaseEdge, Edge, EdgeIterator> { + public: + /** + * Constructor. + * @param edges Array of edges to be iterated over. + * @param current ID of current edge's end node. + */ + EdgeIterator(BaseEdge *edges, NodeID current) : + BaseEdgeIterator<BaseEdge, Edge, EdgeIterator>(edges, current) {} + }; + + /** + * Constant node class. Only retrieval operations are allowed on both the + * node itself and its edges. + */ + class ConstNode : public NodeWrapper<const BaseNode, const BaseEdge> { + public: + /** + * Constructor. + * @param lg LinkGraph to get the node from. + * @param node ID of the node. + */ + ConstNode(const LinkGraph *lg, NodeID node) : + NodeWrapper<const BaseNode, const BaseEdge>(lg->nodes[node], lg->edges[node], node) + {} + + /** + * Get a ConstEdge. This is not a reference as the wrapper objects are + * not actually persistent. + * @param to ID of end node of edge. + * @return Constant edge wrapper. + */ + ConstEdge operator[](NodeID to) const { return ConstEdge(this->edges[to]); } + + /** + * Get an iterator pointing to the start of the edges array. + * @return Constant edge iterator. + */ + ConstEdgeIterator Begin() const { return ConstEdgeIterator(this->edges, this->index); } + + /** + * Get an iterator pointing beyond the end of the edges array. + * @return Constant edge iterator. + */ + ConstEdgeIterator End() const { return ConstEdgeIterator(this->edges, INVALID_NODE); } + }; + + /** + * Updatable node class. The node itself as well as its edges can be modified. + */ + class Node : public NodeWrapper<BaseNode, BaseEdge> { + public: + /** + * Constructor. + * @param lg LinkGraph to get the node from. + * @param node ID of the node. + */ + Node(LinkGraph *lg, NodeID node) : + NodeWrapper<BaseNode, BaseEdge>(lg->nodes[node], lg->edges[node], node) + {} + + /** + * Get an Edge. This is not a reference as the wrapper objects are not + * actually persistent. + * @param to ID of end node of edge. + * @return Edge wrapper. + */ + Edge operator[](NodeID to) { return Edge(this->edges[to]); } + + /** + * Get an iterator pointing to the start of the edges array. + * @return Edge iterator. + */ + EdgeIterator Begin() { return EdgeIterator(this->edges, this->index); } + + /** + * Get an iterator pointing beyond the end of the edges array. + * @return Constant edge iterator. + */ + EdgeIterator End() { return EdgeIterator(this->edges, INVALID_NODE); } + + /** + * Update the node's supply and set last_update to the current date. + * @param supply Supply to be added. + */ + void UpdateSupply(uint supply) + { + this->node.supply += supply; + this->node.last_update = _date; + } + + /** + * Set the node's demand. + * @param demand New demand for the node. + */ + void SetDemand(uint demand) + { + this->node.demand = demand; + } + + void AddEdge(NodeID to, uint capacity, uint usage = 0); + void UpdateEdge(NodeID to, uint capacity, uint usage = 0); + void RemoveEdge(NodeID to); + }; + + typedef SmallVector<BaseNode, 16> NodeVector; + typedef SmallMatrix<BaseEdge> EdgeMatrix; + + /** Minimum effective distance for timeout calculation. */ + static const uint MIN_TIMEOUT_DISTANCE = 48; + + /** Minimum number of days between subsequent compressions of a LG. */ + static const uint COMPRESSION_INTERVAL = 256; + + /** + * Scale a value from a link graph of age orig_age for usage in one of age + * target_age. Make sure that the value stays > 0 if it was > 0 before. + * @param val Value to be scaled. + * @param target_age Age of the target link graph. + * @param orig_age Age of the original link graph. + * @return scaled value. + */ + inline static uint Scale(uint val, uint target_age, uint orig_age) + { + return val > 0 ? max(1U, val * target_age / orig_age) : 0; + } + + /** Bare constructor, only for save/load. */ + LinkGraph() : cargo(INVALID_CARGO), last_compression(0) {} + /** + * Real constructor. + * @param cargo Cargo the link graph is about. + */ + LinkGraph(CargoID cargo) : cargo(cargo), last_compression(_date) {} + + void Init(uint size); + void Compress(); + void Merge(LinkGraph *other); + + /* Splitting link graphs is intentionally not implemented. + * The overhead in determining connectedness would probably outweigh the + * benefit of having to deal with smaller graphs. In real world examples + * networks generally grow. Only rarely a network is permanently split. + * Reacting to temporary splits here would obviously create performance + * problems and detecting the temporary or permanent nature of splits isn't + * trivial. */ + + /** + * Get a node with the specified id. + * @param num ID of the node. + * @return the Requested node. + */ + inline Node operator[](NodeID num) { return Node(this, num); } + + /** + * Get a const reference to a node with the specified id. + * @param num ID of the node. + * @return the Requested node. + */ + inline ConstNode operator[](NodeID num) const { return ConstNode(this, num); } + + /** + * Get the current size of the component. + * @return Size. + */ + inline uint Size() const { return this->nodes.Length(); } + + /** + * Get date of last compression. + * @return Date of last compression. + */ + inline Date LastCompression() const { return this->last_compression; } + + /** + * Get the cargo ID this component's link graph refers to. + * @return Cargo ID. + */ + inline CargoID Cargo() const { return this->cargo; } + + /** + * Scale a value to its monthly equivalent, based on last compression. + * @param base Value to be scaled. + * @return Scaled value. + */ + inline uint Monthly(uint base) const + { + return base * 30 / (_date - this->last_compression + 1); + } + + NodeID AddNode(const Station *st); + void RemoveNode(NodeID id); + +protected: + friend class LinkGraph::ConstNode; + friend class LinkGraph::Node; + friend const SaveLoad *GetLinkGraphDesc(); + friend const SaveLoad *GetLinkGraphJobDesc(); + friend void SaveLoad_LinkGraph(LinkGraph &lg); + + CargoID cargo; ///< Cargo of this component's link graph. + Date last_compression; ///< Last time the capacities and supplies were compressed. + NodeVector nodes; ///< Nodes in the component. + EdgeMatrix edges; ///< Edges in the component. +}; + +#define FOR_ALL_LINK_GRAPHS(var) FOR_ALL_ITEMS_FROM(LinkGraph, link_graph_index, var, 0) + +#endif /* LINKGRAPH_H */ |