megaco_digit_map.erl

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%% ``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 via the world wide web 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.
%% 
%% The Initial Developer of the Original Code is Ericsson Utvecklings AB.
%% Portions created by Ericsson are Copyright 1999, Ericsson Utvecklings
%% AB. All Rights Reserved.''
%% 
%%     $Id$
%%
%%----------------------------------------------------------------------
%% Purpose: Parse and evaluate digit maps
%%----------------------------------------------------------------------
%%
%% digitMap           =  digitString
%%                    /   LWSP "(" LWSP digitStringList LWSP ")" LWSP 
%% digitStringList    = digitString *( LWSP "|" LWSP digitString ) 
%% digitString        = 1*(digitStringElement) 
%% digitStringElement = digitPosition [DOT] 
%% digitPosition      = digitMapLetter / digitMapRange
%% digitMapRange      = ("x" / LWSP "[" LWSP digitLetter LWSP "]" LWSP)
%% digitLetter        = *((DIGIT "-" DIGIT ) / digitMapLetter)
%% digitMapLetter     = DIGIT   ; Basic event symbols 
%%                    / %x41-4B ; a-k
%%                    / %x61-6B ; A-K 
%%                    / "T"     ; Start inter-event timers
%%                    / "S"     ; Short inter-event timers
%%                    / "L"     ; Long  inter-event timers, e.g. 16 sec
%%                    / "Z"     ; Long duration modifier
%% DIGIT              = %x30-39 ; 0-9 
%%                   
%%----------------------------------------------------------------------
%% Example of a digit map:
%% 
%% (0| 00|[1-7]xxx|8xxxxxxx|Fxxxxxxx|Exx|91xxxxxxxxxx|9011x.) 
%% 
%% DM = "(0| 00|[1-7]xxx|8xxxxxxx|Fxxxxxxx|Exx|91xxxxxxxxxx|9011x.)".
%% DM = "xxx | xxL3 | xxS4".
%% megaco:parse_digit_map(DM).
%% megaco:test_digit_event(DM, "1234").
%% megaco:test_digit_event(DM, "12ssss3").
%% megaco:test_digit_event(DM, "12ssss4").
%% megaco:test_digit_event(DM, "12ssss5").
%% 
%%----------------------------------------------------------------------

-module(megaco_digit_map).

-export([parse/1, eval/1, eval/2, report/2, test/2]). % Public
-export([test_eval/2]).                               % Internal

-include_lib("megaco/src/app/megaco_internal.hrl").
-include("megaco_message_internal.hrl").
-include_lib("megaco/src/text/megaco_text_tokens.hrl").

-record(state_transition, {mode, next, cont}).

-record(timers, {mode       = state_dependent,
		 start 	    = 0,
		 short 	    = timer_to_millis(3), 
		 long  	    = timer_to_millis(9),
		 duration   = 100,      % (not used) 100 ms <-> 9.9 sec
		 unexpected = reject}). % ignore | reject


%%----------------------------------------------------------------------
%% Parses a digit map body, represented as a list of chars,
%% into a list of state transitions.
%% 
%% Returns {ok, StateTransitionList} | {error, Reason}
%% 
%%----------------------------------------------------------------------

parse(DigitMapBody) when list(DigitMapBody) ->
    ?d("parse -> entry with"
       "~n   DigitMapBody: ~p", [DigitMapBody]),
    case parse_digit_map(DigitMapBody) of
	{ok, STL} ->
	    {ok, duration_cleanup(STL, [])};
	{error, Reason} ->
	    {error, Reason}
    end;
parse(_DigitMapBody) ->
    {error, not_a_digit_map_body}.

duration_cleanup([], Acc) ->
    Acc;
duration_cleanup([STL|T], Acc) ->
    #state_transition{cont = Events} = STL,
    Events2 = duration_events_cleanup(Events, []),
    duration_cleanup(T, [STL#state_transition{cont = Events2}|Acc]).

duration_events_cleanup([], Acc) ->
    lists:reverse(Acc);
duration_events_cleanup([duration_event, Event|Events], Acc) ->
    duration_events_cleanup(Events, [{duration_event, Event}|Acc]);
duration_events_cleanup([Event|Events], Acc) ->
    duration_events_cleanup(Events, [Event|Acc]).
    
parse_digit_map(Chars) ->
    parse_digit_map(Chars, 1, [], []).

parse_digit_map(Chars, Line, DS, STL) ->
    ?d("parse_digit_map -> entry with"
       "~n   Chars: ~p"
       "~n   DS:    ~p", [Chars, DS]),
    case megaco_text_scanner:skip_sep_chars(Chars, Line) of
	{[], _Line2} when DS /= [] ->
	    case parse_digit_string(DS) of
		{ok, DS2} ->
		    ST = #state_transition{mode = state_dependent,
					   next = start,
					   cont = DS2},
		    STL2 = lists:reverse([ST | STL]),
		    {ok, STL2};
		{error, Reason} ->
		    {error, Reason}
	    end;
	{[Char | Chars2], Line2} ->
	    case Char of
		$( when DS == [], STL == [] ->
		    parse_digit_map(Chars2, Line2, DS, STL);
		$) when DS /= [] ->
		    case megaco_text_scanner:skip_sep_chars(Chars2, Line2) of
			{[], _Line3} ->
			    case parse_digit_string(DS) of
				{ok, DS2} ->
				    ST = #state_transition{mode = state_dependent,
							   next = start,
							   cont = DS2},
				    STL2 = lists:reverse([ST | STL]),
				    {ok, STL2};
				{error, Reason} ->
				    {error, Reason}
			    end;
			{Chars3, Line3} ->
			    Trash =  lists:reverse(Chars3),
			    {error, {round_bracket_mismatch, Trash, Line3}}
		    end;
		$| when DS /= [] ->
		    case parse_digit_string(DS) of
			{ok, DS2} ->
			    ST = #state_transition{mode = state_dependent,
						   next = start,
						   cont = DS2},
			    parse_digit_map(Chars2, Line2, [], [ST | STL]);
			{error, Reason} ->
			    {error, Reason}
		    end;
		_ when Char /= $(, Char /= $|, Char /= $) ->
		    parse_digit_map(Chars2, Line2, [Char | DS], STL);
		_ ->
		    {error, {round_bracket_mismatch, Line2}}
	    end;
	{[], Line2} ->
	    {error, {digit_string_expected, Line2}}
    end.

parse_digit_string(Chars) ->
    ?d("parse_digit_string -> entry with"
       "~n   Chars: ~p", [Chars]),
    parse_digit_string(Chars, []).

parse_digit_string([Char | Chars], DS) ->
    ?d("parse_digit_string -> entry with"
       "~n   Char:  ~p"
       "~n   Chars: ~p"
       "~n   DS:    ~p", [[Char], Chars, DS]),
    case Char of
	$] ->
	    parse_digit_letter(Chars, [], DS);
	$[ ->
	    {error, square_bracket_mismatch};
	$x ->
	    parse_digit_string(Chars, [{range, $0, $9} | DS]);
	$. ->
	    parse_digit_string(Chars, [zero_or_more | DS]);

	I when I >= $0, I =< $9 ->
	    parse_digit_string(Chars, [{single, I} | DS]);

	A when A >= $a, A =< $k ->
	    parse_digit_string(Chars, [{single, A} | DS]);
	A when A >= $A, A =< $K ->
	    parse_digit_string(Chars, [{single, A} | DS]);

	$S ->
	    parse_digit_string(Chars, [use_short_timer | DS]);
	$s ->
	    parse_digit_string(Chars, [use_short_timer | DS]);

	$L ->
	    parse_digit_string(Chars, [use_long_timer | DS]);
	$l ->
	    parse_digit_string(Chars, [use_long_timer | DS]);

        $Z when length(Chars) > 0 ->
            parse_digit_string(Chars, [duration_event | DS]);
        $z when length(Chars) > 0 ->
            parse_digit_string(Chars, [duration_event | DS]);

        $Z ->
            {error, duration_not_allowed_as_last_char};
        $z ->
            {error, duration_not_allowed_as_last_char};

	BadChar ->
	    {error, {illegal_char_in_digit_string, BadChar}}
    end;
parse_digit_string([], DM) ->
    ?d("parse_digit_string -> entry when done with"
       "~n   DM: ~p", [DM]),
    {ok, DM}.


parse_digit_letter([Char | Chars], DL, DS) ->
    ?d("parse_digit_letter -> entry with"
       "~n   Char:  ~p"
       "~n   Chars: ~p"
       "~n   DL:    ~p"
       "~n   DS:    ~p", [[Char], Chars, DL, DS]),
    case Char of
	$[ ->
	    parse_digit_string(Chars, [DL | DS]);
	$] ->
	    {error, square_bracket_mismatch};
	To when To >= $0, To =< $9 ->
	    case Chars of
		[$-, From | Chars2] when From >= $0, From =< $9 ->
		    parse_digit_letter(Chars2, [{range, From, To} | DL], DS);
		_ ->
		    parse_digit_letter(Chars, [{single, To} | DL], DS)
	    end;

	A when A >= $a, A =< $k ->
	    parse_digit_letter(Chars, [{single, A} | DL], DS);
	A when A >= $A, A =< $K ->
	    parse_digit_letter(Chars, [{single, A} | DL], DS);

	$S ->
	    parse_digit_letter(Chars, [use_short_timer | DL], DS);
	$s ->
	    parse_digit_letter(Chars, [use_short_timer | DL], DS);

	$L ->
	    parse_digit_letter(Chars, [use_long_timer | DL], DS);
	$l ->
	    parse_digit_letter(Chars, [use_long_timer | DL], DS);

	$Z ->
	    parse_digit_letter(Chars, [duration_event | DL], DS);
	$z ->
	    parse_digit_letter(Chars, [duration_event | DL], DS);

	BadChar ->
	    {error, {illegal_char_between_square_brackets, BadChar}}
    end;
parse_digit_letter([], _DL, _DS) ->
    {error, square_bracket_mismatch}.


%%----------------------------------------------------------------------
%% Collect digit map letters according to digit map
%% Returns {ok, Letters} | {error, Reason}
%%----------------------------------------------------------------------
     
eval(DMV) when record(DMV, 'DigitMapValue') ->
    case parse(DMV#'DigitMapValue'.digitMapBody) of
	{ok, DigitMapBody} ->
	    eval(DigitMapBody, DMV);
	{error, Reason} ->
	    {error, Reason}
    end;
eval(STL) when list(STL) ->
     eval(STL, #timers{}).
	
eval(STL, #'DigitMapValue'{startTimer    = Start,
			   shortTimer    = Short,
			   longTimer     = Long,
			   durationTimer = Duration}) ->
    Timers = #timers{start    = timer_to_millis(Start),
		     short    = timer_to_millis(Short),
		     long     = timer_to_millis(Long),
		     duration = duration_to_millis(Duration)},
    eval(STL, Timers);
eval(STL, {ignore, #'DigitMapValue'{startTimer    = Start,
				    shortTimer    = Short,
				    longTimer     = Long,
				    durationTimer = Duration}}) ->
    Timers = #timers{start      = timer_to_millis(Start),
		     short      = timer_to_millis(Short),
		     long       = timer_to_millis(Long),
		     duration   = duration_to_millis(Duration),
		     unexpected = ignore},
    eval(STL, Timers);
eval(STL, {reject, #'DigitMapValue'{startTimer    = Start,
				    shortTimer    = Short,
				    longTimer     = Long,
				    durationTimer = Duration}}) ->
    Timers = #timers{start      = timer_to_millis(Start),
		     short      = timer_to_millis(Short),
		     long       = timer_to_millis(Long),
		     duration   = duration_to_millis(Duration),
		     unexpected = reject},
    eval(STL, Timers);
eval(STL, Timers) when list(STL),
		       record(hd(STL), state_transition),
		       record(Timers, timers) ->
    ?d("eval -> entry with"
       "~n   STL:    ~p"
       "~n   Timers: ~p", [STL, Timers]),
    case collect(start, mandatory_event, Timers, lists:reverse(STL), []) of
	{error, _} = Error ->
	    ?d("eval -> error:"
	       "~n   Error: ~p", [Error]),
	    Error;
	OK ->
	    ?d("eval -> ok:"
	       "~n   OK: ~p", [OK]),
	    OK
    end;
eval(DigitMapBody, ignore) ->
    eval(DigitMapBody, #timers{unexpected = ignore});
eval(DigitMapBody, reject) ->
    eval(DigitMapBody, #timers{unexpected = reject});
eval(DigitMapBody, Timers) ->
    case parse(DigitMapBody) of
	{ok, STL} ->
	    eval(STL, Timers);
	{error, Reason} ->
	    {error, Reason}
    end.

%% full | unambiguous

collect(Event, State, Timers, STL, Letters) ->
    ?d("collect -> entry with"
       "~n   Event:  ~p"
       "~n   State:  ~p"
       "~n   Timers: ~p"
       "~n   STL:    ~p", [Event, State, Timers, STL]),
    case handle_event(Event, State, Timers, STL, Letters) of
	{completed_full, _Timers2, _STL2, Letters2} ->
	    completed(full, Letters2);
	{completed, _Timers2, _STL2, Letters2} ->
	    completed(unambiguous, Letters2);
	{State2, Timers2, STL2, Letters2} ->
	    ?d("collect -> "
	       "~n   State2:   ~p"
	       "~n   Timers2:  ~p"
	       "~n   Letters2: ~p", [State2, Timers2, Letters2]),
	    MaxWait = choose_timer(State2, Event, Timers2),
	    ?d("collect -> Timer choosen: "
	       "~n   MaxWait: ~p", [MaxWait]),
	    receive
		{?MODULE, _FromPid, Event2} ->
		    ?d("collect -> Got event: "
		       "~n   ~p", [Event2]),
		    collect(Event2, State2, Timers2, STL2, Letters2)
	    after MaxWait ->
		    ?d("collect -> timeout after ~w", [MaxWait]),
		    collect(inter_event_timeout, 
			    State2, Timers2, STL2, Letters2)
	    end;

	{error, Reason} ->
	    ?d("collect -> error: "
	       "~n   Reason: ~p", [Reason]),
	    {error, Reason}
    end.

choose_timer(_State, start, #timers{start = 0}) ->
    ?d("choose_timer(start) -> entry", []),
    infinity;
choose_timer(_State, start, #timers{start = T}) ->
    ?d("choose_timer(start) -> entry with"
       "~n   T: ~p", [T]),
    T;
choose_timer(State, _Event, T) ->
    ?d("choose_timer(~p) -> entry with"