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| author | Erlang/OTP <[email protected]> | 2009-11-20 14:54:40 +0000 |
|---|---|---|
| committer | Erlang/OTP <[email protected]> | 2009-11-20 14:54:40 +0000 |
| commit | 84adefa331c4159d432d22840663c38f155cd4c1 (patch) | |
| tree | bff9a9c66adda4df2106dfd0e5c053ab182a12bd /erts/example/next_perm.erl | |
| download | otp-84adefa331c4159d432d22840663c38f155cd4c1.tar.gz otp-84adefa331c4159d432d22840663c38f155cd4c1.tar.bz2 otp-84adefa331c4159d432d22840663c38f155cd4c1.zip | |
The R13B03 release.OTP_R13B03
Diffstat (limited to 'erts/example/next_perm.erl')
| -rw-r--r-- | erts/example/next_perm.erl | 66 |
1 files changed, 66 insertions, 0 deletions
diff --git a/erts/example/next_perm.erl b/erts/example/next_perm.erl new file mode 100644 index 0000000000..40a5c24d35 --- /dev/null +++ b/erts/example/next_perm.erl @@ -0,0 +1,66 @@ +%%
+%% %CopyrightBegin%
+%% +%% Copyright Ericsson AB 2006-2009. 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%
+%%
+-module(next_perm).
+
+-export([next_perm/1, prev_perm/1, load/0, all_perm/1]).
+
+load() ->
+ case whereis(next_perm) of
+ undefined ->
+ case erl_ddll:load_driver(".", "next_perm") of
+ ok -> ok;
+ {error, already_loaded} -> ok;
+ E -> exit(E)
+ end,
+ Port = open_port({spawn, "next_perm"}, []),
+ register(next_perm, Port);
+ _ ->
+ ok
+ end.
+
+list_to_integer_binaries(L) ->
+ [<<I:32/integer-native>> || I <- L].
+
+next_perm(L) ->
+ next_perm(L, 1).
+
+prev_perm(L) ->
+ next_perm(L, 2).
+
+next_perm(L, Nxt) ->
+ load(),
+ B = list_to_integer_binaries(L),
+ Port = whereis(next_perm),
+ port_command(Port, [Nxt, B]),
+ receive
+ [Port | Result] ->
+ Result
+ end.
+
+all_perm(L) ->
+ New = prev_perm(L),
+ all_perm(New, L, [New]).
+
+all_perm(L, L, Acc) ->
+ Acc;
+all_perm(L, Orig, Acc) ->
+ New = prev_perm(L),
+ all_perm(New, Orig, [New | Acc]).
+
+
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