%%%----------------------------------------------------------------------
%%% File    : iconv.erl
%%% Author  : Alexey Shchepin <alexey@process-one.net>
%%% Purpose : Interface to libiconv
%%% Created : 16 Feb 2003 by Alexey Shchepin <alexey@process-one.net>
%%%
%%%
%%% ejabberd, Copyright (C) 2002-2013   ProcessOne
%%%
%%% This program is free software; you can redistribute it and/or
%%% modify it under the terms of the GNU General Public License as
%%% published by the Free Software Foundation; either version 2 of the
%%% License, or (at your option) any later version.
%%%
%%% This program is distributed in the hope that it will be useful,
%%% but WITHOUT ANY WARRANTY; without even the implied warranty of
%%% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
%%% General Public License for more details.
%%%
%%% You should have received a copy of the GNU General Public License
%%% along with this program; if not, write to the Free Software
%%% Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
%%% 02111-1307 USA
%%%
%%%----------------------------------------------------------------------

-module(iconv).

-author('alexey@process-one.net').

-behaviour(gen_server).

-export([start/0, start_link/0, convert/3]).

%% Internal exports, call-back functions.
-export([init/1, handle_call/3, handle_cast/2,
	 handle_info/2, code_change/3, terminate/2]).

start() ->
    gen_server:start({local, ?MODULE}, ?MODULE, [], []).

start_link() ->
    gen_server:start_link({local, ?MODULE}, ?MODULE, [],
			  []).

init([]) ->
    case erl_ddll:load_driver(ejabberd:get_so_path(),
			      iconv_erl)
	of
      ok -> ok;
      {error, already_loaded} -> ok
    end,
    Port = open_port({spawn, "iconv_erl"}, []),
    ets:new(iconv_table, [set, public, named_table]),
    ets:insert(iconv_table, {port, Port}),
    {ok, Port}.

%%% --------------------------------------------------------
%%% The call-back functions.
%%% --------------------------------------------------------

handle_call(_, _, State) -> {noreply, State}.

handle_cast(_, State) -> {noreply, State}.

handle_info({'EXIT', Port, Reason}, Port) ->
    {stop, {port_died, Reason}, Port};
handle_info({'EXIT', _Pid, _Reason}, Port) ->
    {noreply, Port};
handle_info(_, State) -> {noreply, State}.

code_change(_OldVsn, State, _Extra) -> {ok, State}.

terminate(_Reason, Port) -> Port ! {self, close}, ok.

-spec convert(binary(), binary(), binary()) -> binary().

convert(From, To, String) ->
    [{port, Port} | _] = ets:lookup(iconv_table, port),
    Bin = term_to_binary({From, To, String}),
    BRes = port_control(Port, 1, Bin),
    (BRes).