reserve.h File Reference

Connection routing, checking seat availability and reservation. More...

#include "osurs/network.h"

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Functions
Connection *	new_connection (const Node *orig, const Node *dest, int time)
	Create connection between nodes. More...
int	check_connection (Connection *connection, int seats, int *trip_count)
	Check if seats are available in connection. More...
Connection *	select_connection (Connection *connection, int seats)
	Selects the best connection. More...
Reservation *	new_reservation (Connection *connection, int seats, char *id)
	Create a new reservation. More...
void	delete_connection (Connection *connection)
	Delete a connection. More...

Detailed Description

Connection routing, checking seat availability and reservation.

Simple connection routing algorithm without transfers. After checking seat availability in connections reservations can be booked on the network.

Note

There are already powerful routing algorithms for public transport, so the algorithm included here is minimal and only serves to book reservations on already known/found connections to the right segments of the trips (without transfers).

Date

: 2022-07-12

Author

: Merlin Unterfinger

Function Documentation

check_connection()

int check_connection	(	Connection *	connection,
		int	seats,
		int *	trip_count
	)

Check if seats are available in connection.

Check a connection if the desired number of seats is available. This is important since reservations can change or avoid double booking of a searched connection.

Note

This function is called internally by new_reservation(Connection).

Parameters

connection	The queried connection to check.
seats	The number of seats to check.
trip_count	The trip number on the route, needed for getting the reserved count.

Returns

Returns 0 if failure and 1 if success.

delete_connection()

void delete_connection

(

Connection *

connection

)

Delete a connection.

Frees the memory from a connection chain on the heap.

Note

This function has to be called for every queried connection to prevent memory leaks.

Parameters

connection

The connection chain to delete.

new_connection()

Connection* new_connection	(	const Node *	orig,
		const Node *	dest,
		int	time
	)

Create connection between nodes.

Searches connections between nodes on the network considering a departure time. If more than one connection is possible between to nodes on the network, a connection chain is created. In a connection chain, the .last property of the connection structure points to the last connection or NULL if it is the root of the chain. Identically, the .next property points to the next connection or to NULL if it is the end of the chain.

Note

Queried connections are not stored on the network and must be released individually to prevent a memory leak (delete_connection(Connection*)).

Parameters

orig	Origin node in network for connection.
dest	Destination node in network for connection.
time	The departure time in seconds after midnight (00:00:00).

Returns

Returns a pointer to a connection chain or NULL if no connection was found.

new_reservation()

Reservation* new_reservation	(	Connection *	connection,
		int	seats,
		char *	id
	)

Create a new reservation.

Books a connection on the network, if the desired seats are available. If enough seats are available the reservation counts of the corresponding trip on the stops of the routes are increased and a new reservation is allocated and connected to the network.

Parameters

connection	The connection to reserve.
seats	The number of seats to reserve.
id	The UUID of the reservation or NULL to generate a new one.

Returns

Returns a reservation or null if no seats are available.

select_connection()

Connection* select_connection	(	Connection *	connection,
		int	seats
	)

Selects the best connection.

Chooses the best connection based on arrival time and seat availability.

Parameters

connection	Connection results from new_connection().
seats	The number of seats that should be available on the connection.

Returns

The shifted pointer to the best connection (Connection*) or NULL if no suitable connection is found.