From 3c15ff32e89e401b4dde2b8acc9699be2614b996 Mon Sep 17 00:00:00 2001
From: Anders Svensson <anders@erlang.org>
Date: Wed, 18 May 2011 18:29:12 +0200
Subject: Initial commit of the diameter application.

The application provides an implementation of the Diameter protocol
as defined in RFC 3588.
---
 lib/diameter/src/app/diameter_dict.erl | 153 +++++++++++++++++++++++++++++++++
 1 file changed, 153 insertions(+)
 create mode 100644 lib/diameter/src/app/diameter_dict.erl

(limited to 'lib/diameter/src/app/diameter_dict.erl')

diff --git a/lib/diameter/src/app/diameter_dict.erl b/lib/diameter/src/app/diameter_dict.erl
new file mode 100644
index 0000000000..3b9ba00a3f
--- /dev/null
+++ b/lib/diameter/src/app/diameter_dict.erl
@@ -0,0 +1,153 @@
+%%
+%% %CopyrightBegin%
+%%
+%% Copyright Ericsson AB 2010-2011. All Rights Reserved.
+%%
+%% The contents of this file are subject to the Erlang Public License,
+%% Version 1.1, (the "License"); you may not use this file except in
+%% compliance with the License. You should have received a copy of the
+%% Erlang Public License along with this software. If not, it can be
+%% retrieved online at http://www.erlang.org/.
+%%
+%% Software distributed under the License is distributed on an "AS IS"
+%% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
+%% the License for the specific language governing rights and limitations
+%% under the License.
+%%
+%% %CopyrightEnd%
+%%
+
+%%
+%% This module provide OTP's dict interface built on top of ets.
+%%
+%% Note that while the interface is the same as dict the semantics
+%% aren't quite. A Dict here is just a table identifier (although
+%% this fact can't be used if you want dict/ets-based implementations
+%% to be interchangeable) so changes made to the Dict modify the
+%% underlying table. For merge/3, the first argument table is modified.
+%%
+%% The underlying ets table implementing a dict is deleted when the
+%% process from which new() was invoked exits and the dict is only
+%% writable from this process.
+%%
+%% The reason for this is to be able to swap dict/ets-based
+%% implementations: the former is easier to debug, the latter is
+%% faster for larger tables. It's also just a nice interface even
+%% when there's no need for swapability.
+%%
+
+-module(diameter_dict).
+
+-export([append/3,
+         append_list/3,
+         erase/2,
+         fetch/2,
+         fetch_keys/1,
+         filter/2,
+         find/2,
+         fold/3,
+         from_list/1,
+         is_key/2,
+         map/2,
+         merge/3,
+         new/0,
+         store/3,
+         to_list/1,
+         update/3,
+         update/4,
+         update_counter/3]).
+
+%%% ----------------------------------------------------------
+%%% EXPORTED INTERNAL FUNCTIONS
+%%% ----------------------------------------------------------
+
+append(Key, Value, Dict) ->
+    append_list(Key, [Value], Dict).
+
+append_list(Key, ValueList, Dict)
+  when is_list(ValueList) ->
+    update(Key, fun(V) -> V ++ ValueList end, ValueList, Dict).
+
+erase(Key, Dict) ->
+    ets:delete(Dict, Key),
+    Dict.
+
+fetch(Key, Dict) ->
+    {ok, V} = find(Key, Dict),
+    V.
+
+fetch_keys(Dict) ->
+    ets:foldl(fun({K,_}, Acc) -> [K | Acc] end, [], Dict).
+
+filter(Pred, Dict) ->
+    lists:foreach(fun({K,V}) -> filter(Pred(K,V), K, Dict) end, to_list(Dict)),
+    Dict.
+
+find(Key, Dict) ->
+    case ets:lookup(Dict, Key) of
+        [{Key, V}] ->
+            {ok, V};
+        [] ->
+            error
+    end.
+
+fold(Fun, Acc0, Dict) ->
+    ets:foldl(fun({K,V}, Acc) -> Fun(K, V, Acc) end, Acc0, Dict).
+
+from_list(List) ->
+    lists:foldl(fun store/2, new(), List).
+
+is_key(Key, Dict) ->
+    ets:member(Dict, Key).
+
+map(Fun, Dict) ->
+    lists:foreach(fun({K,V}) -> store(K, Fun(K,V), Dict) end, to_list(Dict)),
+    Dict.
+
+merge(Fun, Dict1, Dict2) ->
+    fold(fun(K2,V2,_) ->
+                 update(K2, fun(V1) -> Fun(K2, V1, V2) end, V2, Dict1)
+         end,
+         Dict1,
+         Dict2).
+
+new() ->
+    ets:new(?MODULE, [set]).
+
+store(Key, Value, Dict) ->
+    store({Key, Value}, Dict).
+
+to_list(Dict) ->
+    ets:tab2list(Dict).
+
+update(Key, Fun, Dict) ->
+    store(Key, Fun(fetch(Key, Dict)), Dict).
+
+update(Key, Fun, Initial, Dict) ->
+    store(Key, map(Key, Fun, Dict, Initial), Dict).
+
+update_counter(Key, Increment, Dict)
+  when is_integer(Increment) ->
+    update(Key, fun(V) -> V + Increment end, Increment, Dict).
+
+%%% ---------------------------------------------------------
+%%% INTERNAL FUNCTIONS
+%%% ---------------------------------------------------------
+
+store({_,_} = T, Dict) ->
+    ets:insert(Dict, T),
+    Dict.
+
+filter(true, _, _) ->
+    ok;
+filter(false, K, Dict) ->
+    erase(K, Dict).
+
+map(Key, Fun, Dict, Error) ->
+    case find(Key, Dict) of
+        {ok, V} ->
+            Fun(V);
+        error ->
+            Error
+    end.
+
-- 
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