We don't need to copy the from/to arrays, we can just iterate backwards.
NB: this makes graph_remove_edge delete only one edge (which is more
consistent with graph_add_edge allowing parallel edges).
Iterating graph->nodes backwards also makes graph_delete_graph faster
since that also iterates backwards.
Signed-off-by: David Lamparter <equinox@opensourcerouting.org>
Iterating over an array while deleting items needs to consider
interactions between the iteration position and deletion. The previous
code completely ignored that problem, leading to memleaks (graph_delete
skipping half of the nodes) and dangling pointers (if parallel edges
exist in graph_remove_edge).
Iterating backwards is safe and reduces "move to fill hole" overhead in
deletion.
Signed-off-by: David Lamparter <equinox@opensourcerouting.org>
Cc: Quentin Young <qlyoung@cumulusnetworks.com>
Ability to remove directed edge between two nodes.
Also ensures that adjacency vectors have no null entries.
Signed-off-by: Quentin Young <qlyoung@cumulusnetworks.com>
