First commit

src/gmhc_counters.erl

@@ -0,0 +1,53 @@
+-module(gmhc_counters).
+
+-export([ initialize/0 ]).
+
+-export([ add/1
+        , add/2
+        , add_read/1
+        , add_read/2
+        , get_value/1
+        , values/0 ]).
+
+counters() ->
+    #{ connector => 1 }.
+
+initialize() ->
+    Counters = counters(),
+    Size = map_size(Counters),
+    CRef = counters:new(Size, []),
+    put_counters(#{ref => CRef, counters => Counters}).
+
+add(Counter) ->
+    add(Counter, 1).
+
+add(Counter, Incr) when is_integer(Incr), Incr >= 0 ->
+    {CRef, Ix} = counter_ix(Counter),
+    counters:add(CRef, Ix, Incr).
+
+add_read(Counter) ->
+    add_read(Counter, 1).
+
+add_read(Counter, Incr) when is_integer(Incr), Incr >= 0 ->
+    {CRef, Ix} = counter_ix(Counter),
+    counters:add(CRef, Ix, Incr),
+    counters:get(CRef, Ix).
+
+get_value(Counter) ->
+    {CRef, Ix} = counter_ix(Counter),
+    counters:get(CRef, Ix).
+
+values() ->
+    #{ref := CRef, counters := Counters} = get_counters(),
+    maps:map(fun(_,Ix) -> counters:get(CRef, Ix) end, Counters).
+                     
+
+counter_ix(Counter) ->
+    #{ref := CRef, counters := #{Counter := Ix}} = get_counters(),
+    {CRef, Ix}.
+
+put_counters(C) ->
+    persistent_term:put(?MODULE, C).
+
+get_counters() ->
+    persistent_term:get(?MODULE).