%% -*- erlang-indent-level: 2 -*-
%%
%% Licensed under the Apache License, Version 2.0 (the "License");
%% you may not use this file except in compliance with the License.
%% You may obtain a copy of the License at
%%
%% http://www.apache.org/licenses/LICENSE-2.0
%%
%% Unless required by applicable law or agreed to in writing, software
%% distributed under the License is distributed on an "AS IS" BASIS,
%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
%% See the License for the specific language governing permissions and
%% limitations under the License.
%%
%%----------------------------------------------------------------------
%% File : hipe_adj_list.erl
%% Author : Andreas Wallin <[email protected]>
%% Purpose : Keeps track of adjacency lists for the inference graph.
%% Created : 18 Mar 2000 by Andreas Wallin <[email protected]>
%%----------------------------------------------------------------------
-module(hipe_adj_list).
-author("Andreas Wallin").
-export([new/1,
add_edge/3,
%% add_edges/3,
remove_edge/3,
%% remove_edges/3,
edges/2]).
%%----------------------------------------------------------------------
%% Function: new
%%
%% Description: Creates an empty structure for adjacency lists
%%
%% Parameters:
%% Max_nodes -- Limit for node numbers
%%
%% Returns:
%% Empty adj_list structure
%%
%%----------------------------------------------------------------------
new(Max_nodes) ->
hipe_vectors:new(Max_nodes, []).
%%----------------------------------------------------------------------
%% Function: add_edges
%%
%% Description: Adds edges from a node to other nodes
%%
%% Parameters:
%% U -- A node
%% Vs -- Nodes to add edges to
%% Adj_list -- Old adjacency lists
%%
%% Returns:
%% An updated adj_list data-structure
%%
%%----------------------------------------------------------------------
%%add_edges(_, [], Adj_list) -> Adj_list;
%%add_edges(U, Vs, Adj_list) when is_list(Vs), is_integer(U) ->
%% hipe_vectors:set(Adj_list, U, ordsets:union(Vs, hipe_vectors:get(Adj_list, U))).
%%----------------------------------------------------------------------
%% Function: add_edge
%%
%% Description: Creates an edge between two nodes
%%
%% Parameters:
%% U -- A node
%% V -- Another node
%% Adj_list -- Old adjacency lists
%%
%% Returns:
%% New adj_list data-structure with (U and V connected)
%%
%%----------------------------------------------------------------------
add_edge(U, V, Adj_list) -> % PRE: U =/= V, not V \in adjList[U]
hipe_vectors:set(Adj_list, U,
[V | hipe_vectors:get(Adj_list, U)]).
%%----------------------------------------------------------------------
%% Function: remove_edges
%%
%% Description: Removes edges from a node to other nodes
%%
%% Parameters:
%% U -- A node
%% Vs -- Nodes to remove edges to
%% Adj_list -- Old adjacency lists
%%
%% Returns:
%% An updated adj_list data-structure
%%
%%----------------------------------------------------------------------
%% remove_edges(_, [], Adj_list) -> Adj_list;
remove_edges(U, Vs, Adj_list) when is_list(Vs), is_integer(U) ->
hipe_vectors:set(Adj_list, U, hipe_vectors:get(Adj_list, U) -- Vs).
%%----------------------------------------------------------------------
%% Function: remove_edge
%%
%% Description: Removes an edge between two nodes
%%
%% Parameters:
%% U -- A node
%% V -- Another node
%% Adj_list -- Old adjacency lists
%%
%% Returns:
%% New adjacency lists with (U and V not connected)
%%
%%----------------------------------------------------------------------
remove_edge(U, U, Adj_list) -> Adj_list;
remove_edge(U, V, Adj_list) when is_integer(U), is_integer(V) ->
remove_edges(U, [V], Adj_list).
%%----------------------------------------------------------------------
%% Function: edges
%%
%% Description: Tells where the edges of a node go
%%
%% Parameters:
%% U -- A node
%% Adj_list -- Adjacency lists
%%
%% Returns:
%% The set of nodes connected to U
%%
%%----------------------------------------------------------------------
edges(U, Adj_list) ->
hipe_vectors:get(Adj_list, U).
