TSLRouteFinder Class Reference

Detailed Description

This class encapsulates the route-traversal algorithms pertinent to the network.

Clients supply cost methods that are called by the traversal algorithms. Thus, clients are fully in charge of what the meaning of cost is for their application. This could simply be the distance travelled via a link; or it could be the time taken to travel, or the fuel cost, or whatever else. The traversal algorithms simply supply the cost object with the current link and turn; it is up to the cost object how it uses these to compute the real cost of traversal. For example, if an application is routing lorries and links contain information about height restrictions (e.g. low bridges), then clients could initialise a cost object with the type of vehicle that is being routed; the cost object can then determine if the vehicle's height prohibits it travelling down particular links and assign costs accordingly.

Classes
struct	Segment

Public Member Functions
Segment	operator[] (int N) const
void	destroy ()
TSLPolyline *	generatePolyline (int from=-1, int to=-1)
double	get_cost (int N) const
const TSLLink *	get_link (int N) const
const TSLNode *	get_node (int N) const
int	link_count () const
int	node_count () const
int	shortest_path (const TSLNetwork::node_iterator &from, const TSLNetwork::node_iterator &to, const TSLPathCost::distance_type &maxDist=TSLPathCost::infinity) const

Static Public Member Functions
static TSLRouteFinder *	make (const TSLNetwork *nwk, const TSLPathCost &cost)

Member Function Documentation

destroy()

void TSLRouteFinder::destroy

(

)

Destroy the object.

generatePolyline()

TSLPolyline * TSLRouteFinder::generatePolyline	(	int	from = -1,
		int	to = -1 )

Generates a TSLPolyline composed from the links between the node identified by the from index and the node identified by the to index (these indices relate to the node position in the route, e.g. 3rd node to 7th node). The client is responsible for managing any TSLPolylines created.

Parameters

from	The index of the node to start the polyline from.
to	The index of the node to end the polyline on.

Returns

a pointer to a TSLPolyline object if generation was successful, 0 otherwise.

get_cost()

double TSLRouteFinder::get_cost

(

int

N

)

const

Access method for the path cost.

Parameters

N	The Nth node of the route.

Returns

the path's cost to the given node in the route.

get_link()

const TSLLink * TSLRouteFinder::get_link

(

int

N

)

const

Access method for a link in the path.

Parameters

N	The Nth link of the route.

Returns

the path's link at the given position in the route.

get_node()

const TSLNode * TSLRouteFinder::get_node

(

int

N

)

const

Access method for a node in the path.

Parameters

N	The Nth node of the route.

Returns

the path's node at the given position in the route.

link_count()

int TSLRouteFinder::link_count

(

)

const

Query method for the number of links in the route.

make()

static TSLRouteFinder * TSLRouteFinder::make ( const TSLNetwork * nwk, const TSLPathCost & cost )

static

Create a TSLRouteFinder object, associating a network and cost object with it. The client is responsible for destroying the object.

NOTE: The TSLRouteFinder object does NOT make a copy of the cost object passed to it. Therefore the client must ensure that the cost object remains valid for the lifetime of the TSLRouteFinder object.

Parameters

nwk	The network for which routing will be performed.
cost	The cost object.

node_count()

int TSLRouteFinder::node_count

(

)

const

Query method for the number of nodes in the route.

operator[]()

Segment TSLRouteFinder::operator[]

(

int

N

)

const

Access method for the path.

Parameters

N	The index.

Returns

the path's Segment at the given index.

shortest_path()

int TSLRouteFinder::shortest_path	(	const TSLNetwork::node_iterator &	from,
		const TSLNetwork::node_iterator &	to,
		const TSLPathCost::distance_type &	maxDist = TSLPathCost::infinity ) const

Find the shortest-path through the network given the start and end points. The optional maxDist argument specifies an effective radius (from the start) beyond which links & nodes are not searched.

Parameters

from	A reference to the network node_iterator pointing to the start node.
to	A reference to the network node_iterator pointing to the finish node.
maxDist	An upper bound for the cost of a path. Links from nodes whose cost exceeds maxDist will not be traversed.

Returns

the number of Segments that the path is made up of.