megaco_sdp.erl

OTP是开放电信平台的简称

encode_rtimes_repeat(Repeat) when is_list(Repeat) ->
    Repeat;
encode_rtimes_repeat(BadRepeat) ->
    error({invalid_rtimes_repeat, BadRepeat}).

encode_rtimes_duration(Duration) when is_list(Duration) ->
    Duration;
encode_rtimes_duration(BadDuration) ->
    error({invalid_rtimes_duration, BadDuration}).

encode_rtimes_list_of_offsets(LOO) when is_list(LOO) ->
    F = fun(Off, Acc) when is_list(Off) -> 
		Acc ++ " " ++ Off;
	   (BadOff, Acc) -> 
		error({invalid_rtimes_list_of_offsets, {BadOff, Acc}})
	end,
    lists:foldl(F, [], LOO);
encode_rtimes_list_of_offsets(BadLoo) ->
    error({invalid_rtimes_list_of_offsets, BadLoo}).
    
	    
decode_pp_tzones(Value) ->
    ?d("decode_pp_ztimes -> entry with"
       "~n   Value: ~p", [Value]),
    List = string:tokens(Value, " \t"),
    {ok, #megaco_sdp_z{list_of_adjustments = List}}.

encode_pp_tzones(LOA) ->
    ?d("encode_pp_ztimes -> entry with"
       "~n   LOA: ~p", [LOA]),
    Val = encode_tzones_list_of_adjustments(LOA),
    #'PropertyParm'{name  = "z", 
		    value = [Val]}.

encode_tzones_list_of_adjustments([H|T]) when is_list(H) ->
    F = fun(Adjustment, Acc) when is_list(Adjustment) -> 
		Acc ++ " " ++ Adjustment;
	   (BadAdjustment, Acc) ->
		error({invalid_tzones_list_of_adjustments, 
		       {BadAdjustment, Acc}})
	end, 
    lists:foldl(F, H, T);
encode_tzones_list_of_adjustments(LOA) ->
    error({invalid_tzones_list_of_adjustments, LOA}).


%% ===== Encryption Keys =====
%% 
decode_pp_encryption_keys(Value) ->
    ?d("decode_pp_encryption_keys -> entry with"
       "~n   Value: ~p", [Value]),
    {M, E} = 
	case string:tokens(Value, ":") of
	    [Method, EncryptionKey] -> 
		?d("decode_pp_encryption_keys -> "
		   "~n   Method:        ~p"
		   "~n   EncryptionKey: ~p", [Method, EncryptionKey]),
		{Method, EncryptionKey};
	    [Method] -> 
		?d("decode_pp_encryption_keys -> "
		   "~n   Method: ~p", [Method]),
		{Method, undefined};
	    Err ->
		invalid_pp(encryption_key, Value, Err)
	end,
    M2 = 
	case tolower(M) of
	    "prompt" ->
		prompt;
	    "clear" ->
		clear;
	    "base64" ->
		base64;
	    "uri" ->
		uri;
	    _ ->
		M
	end,
    ?d("decode_pp_encryption_keys -> "
       "~n   M2: ~p", [M2]),
    SDP = #megaco_sdp_k{method         = M2, 
			encryption_key = E},
    {ok, SDP}.
    
encode_pp_encryption_keys(prompt = _Method, undefined) ->
    ?d("encode_pp_encryption_keys(prompt) -> entry", []),
    #'PropertyParm'{name  = "k", 
		    value = ["prompt"]};
encode_pp_encryption_keys(clear = _Method, EncryptionKey) 
  when is_list(EncryptionKey) ->
    ?d("encode_pp_encryption_keys(clear) -> entry with"
       "~n   EncryptionKey: ~p", [EncryptionKey]),
    #'PropertyParm'{name  = "k", 
		    value = ["clear:" ++ EncryptionKey]};
encode_pp_encryption_keys(base64 = _Method, EncryptionKey) 
  when is_list(EncryptionKey) ->
    ?d("encode_pp_encryption_keys(base64) -> entry with"
       "~n   EncryptionKey: ~p", [EncryptionKey]),
    #'PropertyParm'{name  = "k", 
		    value = ["base64:" ++ EncryptionKey]};
encode_pp_encryption_keys(uri = _Method, EncryptionKey) 
  when is_list(EncryptionKey) ->
    ?d("encode_pp_encryption_keys(uri) -> entry with"
       "~n   EncryptionKey: ~p", [EncryptionKey]),
    #'PropertyParm'{name  = "k", 
		    value = ["uri:" ++ EncryptionKey]};
encode_pp_encryption_keys(Method, EncryptionKey) 
  when is_list(Method) and is_list(EncryptionKey) ->
    ?d("encode_pp_encryption_keys -> entry with"
       "~n   Method:        ~p"
       "~n   EncryptionKey: ~p", [Method, EncryptionKey]),
    #'PropertyParm'{name  = "k", 
		    value = [Method ++ ":" ++ EncryptionKey]};
encode_pp_encryption_keys(BadMethod, BadEK) ->
    error({invalid_encryption_keys, {BadMethod, BadEK}}).

    
%% ===== Attributes =====
%% 
decode_pp_attribute(Value) ->
    ?d("decode_pp_attribute -> entry with"
       "~n   Value: ~p", [Value]),
    case string:tokens(Value, ":") of
	["rtpmap", AttrValue] ->
	    ?d("decode_pp_attribute -> rtpmap: "
	       "~n   AttrValue: ~p", [AttrValue]),
	    case string:tokens(AttrValue, "\/ \t") of
		[PayloadStr, EncName, ClockRateStr | EncPar] ->
		    ?d("decode_pp_attribute -> "
		       "~n   PayloadStr:   ~p"
		       "~n   EncName:      ~p"
		       "~n   ClockRateStr: ~p"
		       "~n   EncPar:       ~p", 
		       [PayloadStr, EncName, ClockRateStr, EncPar]),
		    Payload   = s2i(PayloadStr, invalid_rtpmap_payload),
		    ?d("decode_pp_attribute -> Payload: ~w", [Payload]),
		    ClockRate = s2i(ClockRateStr, invalid_rtpmap_payload), 
		    ?d("decode_pp_attribute -> ClockRate: ~w", [ClockRate]),
		    SDP = #megaco_sdp_a_rtpmap{payload_type   = Payload, 
					       encoding_name  = EncName,
					       clock_rate     = ClockRate, 
					       encoding_parms = EncPar},
		    {ok, SDP};
		_ ->
		    error({invalid_rtpmap, AttrValue})
	    end;

	["ptime", PacketTimeStr] ->
	    ?d("decode_pp_attribute -> ptime: "
	       "~n   PacketTimeStr: ~p", [PacketTimeStr]),
	    PacketTime = s2i(PacketTimeStr, invalid_ptime_packet_time), 
	    ?d("decode_pp_attribute -> PacketTime: ~w", [PacketTime]),
	    SDP = #megaco_sdp_a_ptime{packet_time = PacketTime}, 
	    {ok, SDP};

	["quality", QualityStr] ->
	    ?d("decode_pp_attribute -> quality: "
	       "~n   QualityStr: ~p", [QualityStr]),
	    Quality = s2i(QualityStr, invalid_quality_quality), 
	    ?d("decode_pp_attribute -> Quality: ~w", [Quality]),
	    SDP = #megaco_sdp_a_quality{quality = Quality}, 
	    {ok, SDP};

	["fmtp", FMTP] ->
	    ?d("decode_pp_attribute -> fmtp: "
	       "~n   FMTP: ~p", [FMTP]),
	    case string:tokens(FMTP, " \t") of
		[Fmt, Param] ->
		    ?d("decode_pp_attribute -> "
		       "~n   Fmt:   ~p"
		       "~n   Param: ~p", [Fmt, Param]),
		    SDP = #megaco_sdp_a_fmtp{format = Fmt,
					     param  = Param}, 
		    {ok, SDP};
		_ ->
		    error({invalid_fmtp, FMTP})
	    end;

	[Attr, AttrValue] ->
	    ?d("decode_pp_attribute -> "
	       "~n   Attr:      ~p"
	       "~n   AttrValue: ~p", [Attr, AttrValue]),
	    {ok, #megaco_sdp_a{attribute = Attr, value = AttrValue}};

	[Attr] ->
	    ?d("decode_pp_attribute -> "
	       "~n   Attr: ~p", [Attr]),
	    {ok, #megaco_sdp_a{attribute = Attr}};

	Err ->
	    invalid_pp(invalid_attribute, Value, Err)
    end.
    
encode_pp_attribute_rtpmap(Payload0, EncName0, ClockRate0, EncPar0) ->
    ?d("encode_pp_attribute_rtpmap -> entry with"
       "~n   Payload0:   ~p"
       "~n   EncName0:   ~p"
       "~n   ClockRate0: ~p"
       "~n   EncPar0:    ~p", [Payload0, EncName0, ClockRate0, EncPar0]),
    Payload   = encode_rtpmap_payload(Payload0), 
    EncName   = encode_rtpmap_encoding_name(EncName0), 
    ClockRate = encode_rtpmap_clockrate(ClockRate0), 
    EncPar    = encode_rtpmap_encoding_parms(EncPar0), 
    Val = "rtpmap:" ++ Payload ++ " " ++ 
	EncName ++ "/" ++ ClockRate ++ EncPar, 
    #'PropertyParm'{name  = "a", 
		    value = [Val]}.

encode_rtpmap_payload(Payload) when is_integer(Payload) ->
    integer_to_list(Payload);
encode_rtpmap_payload(BadPayload) ->
    error({invalid_rtpmap_payload, BadPayload}).

encode_rtpmap_encoding_name(EncName) when is_list(EncName) ->
    EncName;
encode_rtpmap_encoding_name(BadEncName) ->
    error({invalid_rtpmap_encoding_name, BadEncName}).

encode_rtpmap_clockrate(ClockRate) when is_integer(ClockRate) ->
    integer_to_list(ClockRate);
encode_rtpmap_clockrate(BadClockRate) ->
    error({invalid_rtpmap_clockrate, BadClockRate}).

encode_rtpmap_encoding_parms(EncPar) when is_list(EncPar) ->
    F = fun(EP, Acc) when is_list(EP) -> 
		Acc ++ "/" ++ EP;
	   (BadEP, Acc) ->
		error({invalid_rtpmap_encoding_parms, {BadEP, Acc}})
	end,
    lists:foldl(F, [], EncPar);
encode_rtpmap_encoding_parms(BadEncPar) ->
    error({invalid_rtpmap_encoding_parms, BadEncPar}).
		

encode_pp_attribute_ptime(PacketTime) when is_integer(PacketTime) ->
    ?d("encode_pp_attribute_ptime -> entry with"
       "~n   PacketTime: ~w", [PacketTime]),
    #'PropertyParm'{name  = "a", 
		    value = ["ptime:" ++ integer_to_list(PacketTime)]};
encode_pp_attribute_ptime(BadPT) ->
    error({invalid_ptime_packet_time, BadPT}).

encode_pp_attribute_quality(Quality) when is_integer(Quality) ->
    ?d("encode_pp_attribute_quality -> entry with"
       "~n   Quality: ~w", [Quality]),
    #'PropertyParm'{name  = "a", 
		    value = ["quality:" ++ integer_to_list(Quality)]};
encode_pp_attribute_quality(BadQ) ->
    error({invalid_quality_quality, BadQ}).

encode_pp_attribute_fmtp(Fmt0, Param0) ->
    ?d("encode_pp_attribute_rtpmap -> entry with"
       "~n   Fmt0:   ~p"
       "~n   Param0: ~p", [Fmt0, Param0]),
    Fmt   = encode_fmtp_format(Fmt0),
    Param = encode_fmtp_param(Param0),
    Val   = "fmtp:" ++ Fmt ++ " " ++ Param, 
    #'PropertyParm'{name  = "a", 
		    value = [Val]}.

encode_fmtp_format(Fmt) when is_list(Fmt) ->
    Fmt;
encode_fmtp_format(BadFmt) ->
    error({invalid_fmtp_format, BadFmt}).

encode_fmtp_param(Param) when is_list(Param) ->
    Param;
encode_fmtp_param(BadParam) ->
    error({invalid_fmtp_param, BadParam}).


encode_pp_attribute(Attr, undefined) when is_list(Attr) ->
    ?d("encode_pp_attribute_rtpmap -> entry with"
       "~n   Attr: ~p", [Attr]),
    #'PropertyParm'{name  = "a", 
		    value = [Attr]};
encode_pp_attribute(Attr, Value) when is_list(Attr) and is_list(Value) ->
    ?d("encode_pp_attribute_rtpmap -> entry with"
       "~n   Attr:  ~p"
       "~n   Value: ~p", [Attr, Value]),
    #'PropertyParm'{name  = "a", 
		    value = [Attr ++ ":" ++ Value]};
encode_pp_attribute(BadAttr, BadAttrValue) ->
    error({invalid_attribute, {BadAttr, BadAttrValue}}).


%% ===== Media Announcements =====
%% 
decode_pp_media_announcement(Value) ->
    case string:tokens(Value, " \t") of
	[Media0, PortInfo, Transport | FMT] ->
	    Media = 
		case tolower(Media0) of
		    "audio"       -> audio;
		    "video"       -> video;
		    "application" -> application;
		    "data"        -> data;
		    "control"     -> control;
		    _             -> Media0
		end,
	    {Port, NoOfPorts} = 
		case string:tokens(PortInfo, "/") of
		    [P1, NP] ->
			{s2i(P1, invalid_media_announcement_port),
			 s2i(NP, invalid_media_announcement_nof_ports)};
		    [P2] ->
			{s2i(P2, invalid_media_announcement_port),
			 undefined};
		    Err ->
			invalid_pp(mnta_port_info, Value, Err)
		end,
	    SDP = #megaco_sdp_m{media     = Media,
				port      = Port,
				num_ports = NoOfPorts,
				transport = Transport,
				fmt_list  = FMT},
	    {ok, SDP};
	Err ->
	    invalid_pp(media_name_transp_addr, Value, Err)
    end.


encode_pp_media_announcement(Media0, Port0, undefined, Transport0, FMT0) ->
    ?d("encode_pp_media_announcement -> entry with"
       "~n   Media0:     ~p"
       "~n   Port0:      ~p"
       "~n   Transport0: ~p"
       "~n   FMT0:       ~p", [Media0, Port0, Transport0, FMT0]),
    Media     = encode_media_announcement_media(Media0),
    Port      = encode_media_announcement_port(Port0),
    Transport = encode_media_announcement_transport(Transport0),
    FMT       = encode_media_announcement_fmt_list(FMT0),
    do_encode_pp_media_announcement(Media, Port, "", Transport, FMT);
encode_pp_media_announcement(Media0, Port0, NumPorts0, Transport0, FMT0) ->
    ?d("encode_pp_media_announcement -> entry with"
       "~n   Media0:     ~p"
       "~n   Port0:      ~p"
       "~n   NumPorts0:  ~p"
       "~n   Transport0: ~p"
       "~n   FMT0:       ~p", [Media0, Port0, NumPorts0, Transport0, FMT0]),
    Media     = encode_media_announcement_media(Media0),
    Port      = encode_media_announcement_port(Port0),
    NumPorts  = encode_media_announcement_num_port(NumPorts0), 
    Transport = encode_media_announcement_transport(Transport0),
    FMT       = encode_media_announcement_fmt_list(FMT0),
    do_encode_pp_media_announcement(Media, Port, NumPorts, Transport, FMT).

do_encode_pp_media_announcement(Media, Port, NumOfPorts, Transport, FMT) ->
    Val = Media ++ " " ++ Port ++ NumOfPorts ++ " " ++ Transport ++ FMT,
    #'PropertyParm'{name  = "m", 
		    value = [Val]}.

encode_media_announcement_media(Media) when is_atom(Media) ->
    MaMedia = [audio, video, application, data, control], 
    case lists:member(Media, MaMedia) of
	true ->
	    atom_to_list(Media);
	false ->
	    error({invalid_media_announcement_media, Media})
    end;
encode_media_announcement_media(Media) when is_list(Media) ->
    Media;
encode_media_announcement_media(BadMedia) ->
    error({invalid_media_announcement_media, BadMedia}).

encode_media_announcement_port(Port) when is_integer(Port) ->
    integer_to_list(Port);
encode_media_announcement_port(BadPort) ->
    error({invalid_media_announcement_port, BadPort}).

encode_media_announcement_num_port(NumPort) when is_integer(NumPort) ->
    "/" ++ integer_to_list(NumPort);
encode_media_announcement_num_port(BadNumPort) ->
    error({invalid_media_announcement_num_port, BadNumPort}).

encode_media_announcement_transport(Transport) when is_list(Transport) ->
    Transport;
encode_media_announcement_transport(BadTransport) ->
    error({invalid_media_announcement_transport, BadTransport}).

encode_media_announcement_fmt_list(FmtList) when is_list(FmtList) ->
    F = fun(FMT, Acc) when is_list(FMT) -> 
		Acc ++ " " ++ FMT;
	   (BadFMT, Acc) ->
		error({invalid_media_announcement_fmt_list, {BadFMT, Acc}})
	end,
    lists:foldl(F, [], FmtList);
encode_media_announcement_fmt_list(BadFmtList) ->
    error({invalid_media_announcement_fmt_list, BadFmtList}).


decode_network_type(NT) when is_list(NT) ->
    case tolower(NT) of
	"in" -> in;
	_    -> NT
    end.

encode_network_type(in)                  -> "IN";
encode_network_type(NT) when is_list(NT) -> NT;
encode_network_type(Bad) ->
    {error, {invalid_network_type, Bad}}.


decode_address_type(AT) when is_list(AT) ->
    case tolower(AT) of
	"ip4" -> ip4;
	"ip6" -> ip6;
	_     -> AT
    end.
	     
encode_address_type(ip4)                 -> "IP4";
encode_address_type(ip6)                 -> "IP6";
encode_address_type(AT) when is_list(AT) -> 
    case toupper(AT) of
	"IP4" -> "IP4";
	"IP6" -> "IP6";
	_     -> AT
    end;
encode_address_type(Crap) ->
    {error, {invalid_address_type, Crap}}.
    

s2i(S, E) ->
    case (catch list_to_integer(S)) of
	I when is_integer(I) ->
	    I;
	_ ->
	    error({E, S})
    end.

-define(LOWER(Char),
        if
            Char >= $A, Char =< $Z ->
                Char - ($A - $a);
            true ->
                Char
        end).
tolower(Chars) ->
    [?LOWER(Char) || Char <- Chars].

-define(UPPER(Char),
        if
            Char >= $a, Char =< $z ->
                Char + ($A - $a);
            true ->
                Char
        end).
toupper(Chars) ->
    [?UPPER(Char) || Char <- Chars].
    
invalid_pp(What, Value, Error) ->
    {error, {invalid_PropertyParm, {What, Value, Error}}}.

error(Reason) ->
    throw({error, Reason}).