%%
%% %CopyrightBegin%
%%
%% Copyright Ericsson AB 1996-2011. All Rights Reserved.
%%
%% 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.
%%
%% %CopyrightEnd%
%%
%%
-module(sounder).
-export([start/0,play/1,new/1,go/0,stop/0,nosound/0,silent/0]).
-include_lib("kernel/include/file.hrl").
%%----------------------------------------------------------------------
%% sounder.erl - An interface to /dev/audio
%%
%% Created by: {lennarto,mike}@erix.ericsson.se
%% Modified by: EV,[email protected]
%%
%% Mod: 6 Jun 1996 by [email protected]
%% The executable sounder will no be looked for in the
%% same directory as from where sounder.jam is loaded.
%%
%%
%% start() - Returns either: ok ,or: silent ,where silent means
%% that no audio capabilities exists but the sounder
%% will work "silently" in order to not break any code.
%%
%% stop() - Returns: ok
%%
%% new(File) - Tries to load the File. At success, a number refering
%% to the File is returned that shall be used with send/1.
%% Otherwise {error,Reason} is returned.
%%
%% play(No) - Tries to execute the sound registered with the number No
%% Returns: ok , or: {error,Reason}
%%
%% silent() - Returns: true ,if no audio capabilities exists, else: false
%%
%% Note: It is also possible to receive: {error,sounder_not_started}
%%
%%----------------------------------------------------------------------
start() ->
case whereis(sounder) of
undefined ->
%% first we check if the workstation has audio capabilities
case file:read_file_info('/dev/audio') of
{ok, FI} when FI#file_info.access==read_write ->
register(sounder, spawn(sounder,go,[])),
ok;
_Other ->
register(sounder, spawn(sounder,nosound,[])),
silent
end;
_Pid ->
ok
end.
stop() ->
catch begin check(),
sounder ! {stop},
ok end.
new(File) when is_list(File) -> new(list_to_atom(File));
new(File) when is_atom(File) ->
catch begin check(),
sounder ! {new,File,self()},
wait_for_ack(sounder) end.
play(No) when is_integer(No) ->
catch begin check(),
sounder ! {play, No, self()},
wait_for_ack(sounder) end.
silent() ->
catch begin check(),
sounder ! {play,silent,self()},
receive {sounder,Answer} -> Answer end end.
go() ->
Port = open_port({spawn,lists:append(bonk:bonk_dir(), "sounder")},[{packet, 2}]),
loop(Port).
loop(Port) ->
receive
{new, File, From} when is_atom(File) ->
Port ! {self(),{command,lists:append([0],atom_to_list(File))}},
From ! {sounder,wait_for_ack(Port)},
loop(Port);
{play,silent,From} ->
From ! {sounder,false},
loop(Port);
{play,No,From} when is_integer(No) ->
Port ! {self(),{command,[No]}},
From ! {sounder,wait_for_ack(Port)},
loop(Port);
{stop} ->
Port ! {self(),close},
exit(normal);
_ ->
loop(Port)
end.
%% The application using sounds can check on silence itself
%% and refrain from playing sounds.
%% Or it can try to play sounds that will be "consumed in silence"
nosound() ->
receive
{new,File,From} when is_atom(File) ->
From ! {sounder,{ok,silent}},
nosound();
{play,silent,From} ->
From ! {sounder,true},
nosound();
{play,No,From} when is_integer(No) ->
From ! {sounder,{error,no_audio_cap}},
nosound();
{stop} ->
exit(normal);
_ ->
nosound()
end.
wait_for_ack(sounder) ->
receive {sounder,Res} -> Res end;
wait_for_ack(Port) when is_port(Port) ->
receive
{Port,{data,"ok"}} ->
ok;
{Port,{data,[No]}} ->
{ok,No};
{Port,{data,Msg}} ->
{error,list_to_atom(Msg)};
{'EXIT',Port,_} ->
exit(port_exited)
end.
check() ->
case whereis(sounder) of
Pid when is_pid(Pid) ->
ok;
undefined ->
throw({error,sounder_not_started})
end.
