aboutsummaryrefslogblamecommitdiffstats
path: root/lib/asn1/src/asn1rt_per_bin_rt2ct.erl
blob: 5997232f13bf502d5c22998d785b5f3869de59c7 (plain) (tree)
1
2
3
4
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141


                   
                                                        















                                                                         



                                     
                               
                                                                    




                                                              
                                       

                                                      


                                                                
                      
 









                                                              
                                       
                               
                                          
                                            








                               











































                                                          









































                                                                               













































































































































                                                                         



















































































                                                                                                                                                                        


















                                                                            
                                                  





















                                                                                     
                                        

                                                  
               



































































                                                                        
                                    



                                                          
                                                              
                                                            









                                                       

























                                                                     





                                                                              




                                                           









                                                                       




















































                                                                                              











































                                                                                  









































                                                                                                                 

































































































































































































































































































































































































































































                                                                                        






                                                

                                                     








                                                        

                                    






                                                


                                      


















                                                                
 


















                                                                       

























































































































































































                                                                                                                                                  
































































































































































                                                                             
                       


      
           
              



                                                   


                                                                 
                                                   



                                











                                                           
%%
%% %CopyrightBegin%
%% 
%% Copyright Ericsson AB 2002-2012. 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(asn1rt_per_bin_rt2ct).
%% encoding / decoding of PER aligned

-include("asn1_records.hrl").

-export([decode_fragmented/3]).
-export([setchoiceext/1, setext/1, fixoptionals/3, fixextensions/2, 
	 skipextensions/3, getbit/1, getchoice/3 ]).
-export([set_choice/3, encode_integer/2, encode_integer/3  ]).
-export([encode_small_number/1,
	 encode_length/2,
	 encode_small_length/1,
	 decode_compact_bit_string/3]).
-export([encode_bit_string/3, decode_bit_string/3  ]).
-export([encode_octet_string/2,
	 encode_object_identifier/1, decode_object_identifier/1,
	 encode_real/1, decode_real/1,
	 encode_relative_oid/1, decode_relative_oid/1,
	 complete/1]).

-export([encode_open_type/2, decode_open_type/2]).

-export([encode_GeneralString/2, decode_GeneralString/2,
	 encode_GraphicString/2, decode_GraphicString/2,
	 encode_TeletexString/2, decode_TeletexString/2,
	 encode_VideotexString/2, decode_VideotexString/2,
	 encode_ObjectDescriptor/2, decode_ObjectDescriptor/1,
	 encode_UTF8String/1,decode_UTF8String/1
	]).

-export([encode_unconstrained_number/1,
	 encode_octet_string/3,
	 encode_known_multiplier_string/5,
	 decode_known_multiplier_string/5]).


-export([eint_positive/1]).
-export([pre_complete_bits/2]).

-define('16K',16384).
-define('32K',32768).
-define('64K',65536).

%%--------------------------------------------------------
%% setchoiceext(InRootSet) -> [{bit,X}]
%% X  is set to  1 when InRootSet==false
%% X  is set to  0 when InRootSet==true
%%
setchoiceext(true) ->
    [0];
setchoiceext(false) ->
    [1].

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% setext(true|false) ->  CompleteList
%%

setext(false) ->
%    [{debug,ext},{bits,1,0}];
    [0];
setext(true) ->
%    [{debug,ext},{bits,1,1}];
    [1].

fixoptionals(OptList,_OptLength,Val) when is_tuple(Val) ->
%    Bits = fixoptionals(OptList,Val,0),
%    {Val,{bits,OptLength,Bits}};
%    {Val,[10,OptLength,Bits]};
    {Val,fixoptionals(OptList,Val,[])};

fixoptionals([],_,Acc) ->
    %% Optbits
    lists:reverse(Acc);
fixoptionals([{Pos,DefVal}|Ot],Val,Acc) ->
    case element(Pos,Val) of
	asn1_DEFAULT -> fixoptionals(Ot,Val,[0|Acc]);
	DefVal -> fixoptionals(Ot,Val,[0|Acc]);
	_ -> fixoptionals(Ot,Val,[1|Acc])
    end;
fixoptionals([Pos|Ot],Val,Acc) ->
    case element(Pos,Val) of
	asn1_NOVALUE -> fixoptionals(Ot,Val,[0|Acc]);
	asn1_DEFAULT -> fixoptionals(Ot,Val,[0|Acc]);
	_ -> fixoptionals(Ot,Val,[1|Acc])
    end.


fixextensions({ext,ExtPos,ExtNum},Val) ->
    case fixextensions(ExtPos,ExtNum+ExtPos,Val,0) of
	0 -> [];
	ExtBits ->
	    [encode_small_length(ExtNum),pre_complete_bits(ExtNum,ExtBits)]
    end.

fixextensions(Pos,MaxPos,_,Acc) when Pos >= MaxPos ->
    Acc;
fixextensions(Pos,ExtPos,Val,Acc) ->
    Bit = case catch(element(Pos+1,Val)) of
	      asn1_NOVALUE ->
		  0;
	      asn1_NOEXTVALUE ->
		  0;
	      {'EXIT',_} ->
		  0;
	      _ ->
		  1
	  end,
    fixextensions(Pos+1,ExtPos,Val,(Acc bsl 1)+Bit).

skipextensions(Bytes,Nr,ExtensionBitstr) when is_bitstring(ExtensionBitstr) -> 
    Prev = Nr - 1,
    case ExtensionBitstr of
	<<_:Prev,1:1,_/bitstring>> ->
	    {_,Bytes2} = decode_open_type(Bytes,[]),
 	    skipextensions(Bytes2, Nr+1, ExtensionBitstr);
	<<_:Prev,0:1,_/bitstring>> ->
	    skipextensions(Bytes, Nr+1, ExtensionBitstr);
	_ ->
	    Bytes
    end.
	

getchoice(Bytes,1,0) -> % only 1 alternative is not encoded
    {0,Bytes};
getchoice(Bytes,_,1) ->
    decode_small_number(Bytes);
getchoice(Bytes,NumChoices,0) ->
    decode_constrained_number(Bytes,{0,NumChoices-1}).


%% getbits_as_binary(Num,Bytes) -> {Bin,Rest}
%% Num = integer(),
%% Bytes = bitstring(),
%% Bin = bitstring(),
%% Rest = bitstring()
getbits_as_binary(Num,Bytes) when is_bitstring(Bytes) ->
    <<BS:Num/bitstring,Rest/bitstring>> = Bytes,
    {BS,Rest}.
    
getbits_as_list(Num,Bytes) when is_bitstring(Bytes) ->
    <<BitStr:Num/bitstring,Rest/bitstring>> = Bytes,
    {[ B || <<B:1>> <= BitStr],Rest}.


getbit(Buffer) ->
    <<B:1,Rest/bitstring>> = Buffer,
    {B,Rest}.


getbits(Buffer,Num) when is_bitstring(Buffer) ->
    <<Bs:Num,Rest/bitstring>> = Buffer,
    {Bs,Rest}.

align(Bin) when is_binary(Bin) ->
    Bin;
align(BitStr) when is_bitstring(BitStr) ->
    AlignBits = bit_size(BitStr) rem 8,
    <<_:AlignBits,Rest/binary>> = BitStr,
    Rest.


%% First align buffer, then pick the first Num octets.
%% Returns octets as an integer with bit significance as in buffer.
getoctets(Buffer,Num) when is_binary(Buffer) ->
    <<Val:Num/integer-unit:8,RestBin/binary>> = Buffer,
    {Val,RestBin};
getoctets(Buffer,Num) when is_bitstring(Buffer) ->
    AlignBits = bit_size(Buffer) rem 8,
    <<_:AlignBits,Val:Num/integer-unit:8,RestBin/binary>> = Buffer,
    {Val,RestBin}.


%% First align buffer, then pick the first Num octets.
%% Returns octets as a binary
getoctets_as_bin(Bin,Num) when is_binary(Bin) ->
    <<Octets:Num/binary,RestBin/binary>> = Bin,
    {Octets,RestBin};
getoctets_as_bin(Bin,Num) when is_bitstring(Bin) ->
    AlignBits = bit_size(Bin) rem 8,
    <<_:AlignBits,Val:Num/binary,RestBin/binary>> = Bin,
    {Val,RestBin}.
    

%% same as above but returns octets as a List
getoctets_as_list(Buffer,Num) ->
    {Bin,Buffer2} = getoctets_as_bin(Buffer,Num),
    {binary_to_list(Bin),Buffer2}.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% set_choice(Alt,Choices,Altnum) -> ListofBitSettings
%% Alt = atom()
%% Altnum = integer() | {integer(),integer()}% number of alternatives
%% Choices = [atom()] | {[atom()],[atom()]}
%% When Choices is a tuple the first list is the Rootset and the
%% second is the Extensions and then Altnum must also be a tuple with the
%% lengths of the 2 lists 
%%
set_choice(Alt,{L1,L2},{Len1,_Len2}) ->
    case set_choice_tag(Alt,L1) of
	N when is_integer(N), Len1 > 1 ->
%	    [{bits,1,0}, % the value is in the root set
%	     encode_constrained_number({0,Len1-1},N)];
	    [0, % the value is in the root set
	     encode_constrained_number({0,Len1-1},N)];
	N when is_integer(N) ->
%	    [{bits,1,0}]; % no encoding if only 0 or 1 alternative
	    [0]; % no encoding if only 0 or 1 alternative
	false ->
%	    [{bits,1,1}, % extension value
	    [1, % extension value
	     case set_choice_tag(Alt,L2) of
		 N2 when is_integer(N2) ->
		     encode_small_number(N2);
		 false ->
		     unknown_choice_alt
	     end]
    end;
set_choice(Alt,L,Len) ->
    case set_choice_tag(Alt,L) of
	N when is_integer(N), Len > 1 ->
	    encode_constrained_number({0,Len-1},N);
	N when is_integer(N) ->
	    []; % no encoding if only 0 or 1 alternative
	false ->
	    [unknown_choice_alt]
    end.

set_choice_tag(Alt,Choices) ->
    set_choice_tag(Alt,Choices,0).

set_choice_tag(Alt,[Alt|_Rest],Tag) ->
    Tag;
set_choice_tag(Alt,[_H|Rest],Tag) ->
    set_choice_tag(Alt,Rest,Tag+1);
set_choice_tag(_Alt,[],_Tag) ->
    false.

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% decode_fragmented_XXX; decode of values encoded fragmented according
%% to ITU-T X.691 clause 10.9.3.8. The unit (XXX) is either bits, octets,
%% characters or number of components (in a choice,sequence or similar).
%% Buffer is a buffer binary().
%% C is the constrained length.
%% If the buffer is not aligned, this function does that.
decode_fragmented_bits(Buffer,C) when is_binary(Buffer) ->
    decode_fragmented_bits(Buffer,C,[]);
decode_fragmented_bits(Buffer,C) when is_bitstring(Buffer) ->
    AlignBits = bit_size(Buffer) rem 8,
    <<_:AlignBits,Rest/binary>> = Buffer,
    decode_fragmented_bits(Rest,C,[]).

decode_fragmented_bits(<<3:2,Len:6,Bin/binary>>,C,Acc) ->
    {Value,Bin2} = split_binary(Bin, Len * ?'16K'), % Len = 1 | 2 | 3 | 4
    decode_fragmented_bits(Bin2,C,[Value|Acc]);
decode_fragmented_bits(<<0:1,0:7,Bin/binary>>,C,Acc) ->
    BinBits = erlang:list_to_bitstring(lists:reverse(Acc)),
    case C of
	Int when is_integer(Int),C == bit_size(BinBits) ->
	    {BinBits,Bin};
	Int when is_integer(Int) ->
	    exit({error,{asn1,{illegal_value,C,BinBits}}})
    end;
decode_fragmented_bits(<<0:1,Len:7,Bin/binary>>,C,Acc) ->
    <<Value:Len/bitstring,Rest/bitstring>> = Bin,
    BinBits = erlang:list_to_bitstring([Value|Acc]),
    case C of
	Int when is_integer(Int),C == bit_size(BinBits) ->
	    {BinBits,Rest};
	Int when is_integer(Int) ->
	    exit({error,{asn1,{illegal_value,C,BinBits}}})
    end.

    
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% encode_open_type(Constraint, Value) -> CompleteList
%% Value = list of bytes of an already encoded value (the list must be flat)
%%         | binary
%% Contraint = not used in this version
%%
encode_open_type(_Constraint, Val) when is_list(Val) ->
    Bin = list_to_binary(Val),
    case size(Bin) of 
	Size when Size>255 ->
	    [encode_length(undefined,Size),[21,<<Size:16>>,Bin]];
	Size ->
	    [encode_length(undefined,Size),[20,Size,Bin]]
    end;
encode_open_type(_Constraint, Val) when is_binary(Val) ->
    case size(Val) of
	Size when Size>255 ->
	    [encode_length(undefined,size(Val)),[21,<<Size:16>>,Val]]; % octets implies align
	Size ->
	    [encode_length(undefined,Size),[20,Size,Val]]
    end.
%% the binary_to_list is not optimal but compatible with the current solution

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% decode_open_type(Buffer,Constraint) -> Value
%% Constraint is not used in this version
%% Buffer = [byte] with PER encoded data 
%% Value = [byte] with decoded data (which must be decoded again as some type)
%%
decode_open_type(Bytes, _Constraint) ->
    {Len,Bytes2} = decode_length(Bytes,undefined),
    getoctets_as_bin(Bytes2,Len).

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% encode_integer(Constraint,Value,NamedNumberList) -> CompleteList
%% encode_integer(Constraint,Value) -> CompleteList
%% encode_integer(Constraint,{Name,Value}) -> CompleteList
%% 
%%
encode_integer(C,V,NamedNumberList) when is_atom(V) ->
    case lists:keysearch(V,1,NamedNumberList) of
	{value,{_,NewV}} -> 
	    encode_integer(C,NewV);
	_ -> 
	    exit({error,{asn1,{namednumber,V}}})
    end;
encode_integer(C,V,_NamedNumberList) when is_integer(V) ->
    encode_integer(C,V);
encode_integer(C,{Name,V},NamedNumberList) when is_atom(Name) ->
    encode_integer(C,V,NamedNumberList).

encode_integer(C,{Name,Val}) when is_atom(Name) ->
    encode_integer(C,Val);

encode_integer([{Rc,_Ec}],Val) when is_tuple(Rc) -> % XXX when is this invoked? First argument most often a list,...Ok this is the extension case...but it doesn't work.
    case (catch encode_integer([Rc],Val)) of
	{'EXIT',{error,{asn1,_}}} ->
%	    [{bits,1,1},encode_unconstrained_number(Val)];
	    [1,encode_unconstrained_number(Val)];
	Encoded ->
%	    [{bits,1,0},Encoded]
	    [0,Encoded]
    end;

encode_integer([],Val) ->
    encode_unconstrained_number(Val);
%% The constraint is the effective constraint, and in this case is a number
encode_integer([{'SingleValue',V}],V) ->
    [];
encode_integer([{'ValueRange',VR={Lb,Ub},Range,PreEnc}],Val) when Val >= Lb,
						Ub >= Val ->
    %% this case when NamedNumberList
    encode_constrained_number(VR,Range,PreEnc,Val);
encode_integer([{'ValueRange',{Lb,'MAX'}}],Val) ->
    encode_semi_constrained_number(Lb,Val);
encode_integer([{'ValueRange',{'MIN',_}}],Val) ->
    encode_unconstrained_number(Val);
encode_integer([{'ValueRange',VR={_Lb,_Ub}}],Val) ->
    encode_constrained_number(VR,Val);
encode_integer(_,Val) ->
    exit({error,{asn1,{illegal_value,Val}}}).

    
%% X.691:10.6 Encoding of a normally small non-negative whole number
%% Use this for encoding of CHOICE index if there is an extension marker in 
%% the CHOICE
encode_small_number({Name,Val}) when is_atom(Name) ->
    encode_small_number(Val);
encode_small_number(Val) when Val =< 63 ->
%    [{bits,1,0},{bits,6,Val}];
%    [{bits,7,Val}]; % same as above but more efficient
    [10,7,Val]; % same as above but more efficient
encode_small_number(Val) ->
%    [{bits,1,1},encode_semi_constrained_number(0,Val)].
    [1,encode_semi_constrained_number(0,Val)].

decode_small_number(Bytes) ->
    {Bit,Bytes2} = getbit(Bytes),
    case Bit of
	0 -> 
	    getbits(Bytes2,6);
	1 ->
	    decode_semi_constrained_number(Bytes2)
    end.

%% X.691:10.7 Encoding of a semi-constrained whole number
%% might be an optimization encode_semi_constrained_number(0,Val) ->
encode_semi_constrained_number(C,{Name,Val}) when is_atom(Name) ->
    encode_semi_constrained_number(C,Val);
encode_semi_constrained_number({Lb,'MAX'},Val) ->
    encode_semi_constrained_number(Lb,Val);
encode_semi_constrained_number(Lb,Val) ->
    Val2 = Val - Lb,
    Oct = eint_positive(Val2),
    Len = length(Oct),
    if 
	Len < 128 ->
	    %{octets,[Len|Oct]}; % equiv with encode_length(undefined,Len) but faster
	    [20,Len+1,[Len|Oct]];
	Len < 256 ->
	    [encode_length(undefined,Len),[20,Len,Oct]];
	true ->
	    [encode_length(undefined,Len),[21,<<Len:16>>,Oct]]
    end.

decode_semi_constrained_number(Bytes) ->
    {Len,Bytes2} = decode_length(Bytes,undefined),
    {V,Bytes3} = getoctets(Bytes2,Len),
    {V,Bytes3}.

encode_constrained_number({Lb,_Ub},_Range,{bits,N},Val) ->
    Val2 = Val-Lb,
%    {bits,N,Val2};
    [10,N,Val2];
encode_constrained_number({Lb,_Ub},_Range,{octets,N},Val) when N < 256->
    %% N is 8 or 16 (1 or 2 octets)
    Val2 = Val-Lb,
%    {octets,<<Val2:N/unit:8>>};
    [20,N,Val2];
encode_constrained_number({Lb,_Ub},_Range,{octets,N},Val) -> % N>255
    %% N is 8 or 16 (1 or 2 octets)
    Val2 = Val-Lb,
%    {octets,<<Val2:N/unit:8>>};
    [21,<<N:16>>,Val2];
encode_constrained_number({Lb,_Ub},Range,_,Val) ->
    Val2 = Val-Lb,
    if
	Range =< 16#1000000  -> % max 3 octets
	    Octs = eint_positive(Val2),
%	    [encode_length({1,3},size(Octs)),{octets,Octs}];
	    L = length(Octs),
	    [encode_length({1,3},L),[20,L,Octs]];
	Range =< 16#100000000  -> % max 4 octets
	    Octs = eint_positive(Val2),
%	    [encode_length({1,4},size(Octs)),{octets,Octs}];
	    L = length(Octs),
	    [encode_length({1,4},L),[20,L,Octs]];
	Range =< 16#10000000000  -> % max 5 octets
	    Octs = eint_positive(Val2),
%	    [encode_length({1,5},size(Octs)),{octets,Octs}];
	    L = length(Octs),
	    [encode_length({1,5},L),[20,L,Octs]];
	true  ->
	    exit({not_supported,{integer_range,Range}})
    end.

encode_constrained_number(Range,{Name,Val}) when is_atom(Name) ->
    encode_constrained_number(Range,Val);
encode_constrained_number({Lb,Ub},Val) when Val >= Lb, Ub >= Val -> 
    Range = Ub - Lb + 1,
    Val2 = Val - Lb,
    if 
	Range  == 1 -> [];
	Range  == 2 ->
%	    Size = {bits,1,Val2};
	    [Val2];
	Range  =< 4 -> 
%	    Size = {bits,2,Val2};
	    [10,2,Val2];
	Range  =< 8 ->
	    [10,3,Val2];
	Range  =< 16 ->
	    [10,4,Val2];
	Range  =< 32 ->
	    [10,5,Val2];
	Range  =< 64 ->
	    [10,6,Val2];
	Range  =< 128 ->
	    [10,7,Val2];
	Range  =< 255 ->
	    [10,8,Val2];
	Range  =< 256 ->
%	    Size = {octets,[Val2]};
	    [20,1,Val2];
	Range  =< 65536 ->
%	    Size = {octets,<<Val2:16>>};
	    [20,2,<<Val2:16>>];
	Range =< (1 bsl (255*8))  ->
            Octs = binary:encode_unsigned(Val2),
            RangeOcts = binary:encode_unsigned(Range - 1),
            OctsLen = erlang:byte_size(Octs),
            RangeOctsLen = erlang:byte_size(RangeOcts),
            LengthBitsNeeded = minimum_bits(RangeOctsLen - 1),
            [10,LengthBitsNeeded,OctsLen-1,20,OctsLen,Octs];
	true  ->
	    exit({not_supported,{integer_range,Range}})
    end;
encode_constrained_number({_,_},Val) -> 
    exit({error,{asn1,{illegal_value,Val}}}).

decode_constrained_number(Buffer,VR={Lb,Ub}) ->
    Range = Ub - Lb + 1,
    decode_constrained_number(Buffer,VR,Range).

decode_constrained_number(Buffer,{Lb,_Ub},Range) ->
						%    Val2 = Val - Lb,
    {Val,Remain} = 
	if 
	    Range  == 1 ->
		{0,Buffer};
	    Range  == 2 ->
		getbits(Buffer,1);
	    Range  =< 4 -> 
		getbits(Buffer,2);
	    Range  =< 8 ->
		getbits(Buffer,3);
	    Range  =< 16 ->
		getbits(Buffer,4);
	    Range  =< 32 ->
		getbits(Buffer,5);
	    Range  =< 64 ->
		getbits(Buffer,6);
	    Range  =< 128 ->
		getbits(Buffer,7);
	    Range  =< 255 ->
		getbits(Buffer,8);
	    Range  =< 256 ->
		getoctets(Buffer,1);
	    Range  =< 65536 ->
		getoctets(Buffer,2);
            Range =< (1 bsl (255*8))  ->
                OList = binary:bin_to_list(binary:encode_unsigned(Range - 1)),
                RangeOctLen = length(OList),
                {Len, Bytes} = decode_length(Buffer, {1, RangeOctLen}),
                {Octs, RestBytes} = getoctets_as_bin(Bytes, Len),
                {binary:decode_unsigned(Octs), RestBytes};
	    true  ->
		exit({not_supported,{integer_range,Range}})
	end,
    {Val+Lb,Remain}.

%% For some reason the minimum bits needed in the length field in
%% the encoding of constrained whole numbers must always be at least 2?
minimum_bits(N) when N < 4 -> 2;
minimum_bits(N) when N < 8 -> 3;
minimum_bits(N) when N < 16 -> 4;
minimum_bits(N) when N < 32 -> 5;
minimum_bits(N) when N < 64 -> 6;
minimum_bits(N) when N < 128 -> 7;
minimum_bits(_N) -> 8.

%% X.691:10.8 Encoding of an unconstrained whole number

encode_unconstrained_number(Val) when Val >= 0 ->
    Oct = eint(Val,[]),
    Len = length(Oct),
    if 
	Len < 128 ->
	    %{octets,[Len|Oct]}; % equiv with encode_length(undefined,Len) but faster
	    [20,Len+1,[Len|Oct]];
	Len < 256 ->
%	    [encode_length(undefined,Len),20,Len,Oct];
	    [20,Len+2,<<2:2,Len:14>>,Oct];% equiv with encode_length(undefined,Len) but faster
	true ->
%	    [encode_length(undefined,Len),{octets,Oct}]
	    [encode_length(undefined,Len),[21,<<Len:16>>,Oct]]
    end;
encode_unconstrained_number(Val) -> % negative
    Oct = enint(Val,[]),
    Len = length(Oct),
    if 
	Len < 128 ->
%	    {octets,[Len|Oct]}; % equiv with encode_length(undefined,Len) but faster
	    [20,Len+1,[Len|Oct]];% equiv with encode_length(undefined,Len) but faster
	Len < 256 ->
%	    [encode_length(undefined,Len),20,Len,Oct];
	    [20,Len+2,<<2:2,Len:14>>,Oct];% equiv with encode_length(undefined,Len) but faster
	true ->
	    %[encode_length(undefined,Len),{octets,Oct}]
	    [encode_length(undefined,Len),[21,<<Len:16>>,Oct]]
    end.


%% used for positive Values which don't need a sign bit
%% returns a list
eint_positive(Val) ->
    case eint(Val,[]) of
	[0,B1|T] ->
	    [B1|T];
	T -> 
	    T
    end.


eint(0, [B|Acc]) when B < 128 ->
    [B|Acc];
eint(N, Acc) ->
    eint(N bsr 8, [N band 16#ff| Acc]).

enint(-1, [B1|T]) when B1 > 127 ->
    [B1|T];
enint(N, Acc) ->
    enint(N bsr 8, [N band 16#ff|Acc]).

%% X.691:10.9 Encoding of a length determinant
%%encode_small_length(undefined,Len) -> % null means no UpperBound
%%    encode_small_number(Len).

%% X.691:10.9.3.5 
%% X.691:10.9.3.7
encode_length(undefined,Len) -> % un-constrained
    if 
	Len < 128 ->
%	    {octets,[Len]};
	    [20,1,Len];
	Len < 16384 ->
	    %{octets,<<2:2,Len:14>>};
	    [20,2,<<2:2,Len:14>>];
	true  -> % should be able to endode length >= 16384 i.e. fragmented length
	    exit({error,{asn1,{encode_length,{nyi,above_16k}}}})
    end;

encode_length({0,'MAX'},Len) ->
    encode_length(undefined,Len);
encode_length(Vr={Lb,Ub},Len) when Ub =< 65535 ,Lb >= 0 -> % constrained
    encode_constrained_number(Vr,Len);
encode_length({Lb,_Ub},Len) when is_integer(Lb), Lb >= 0 -> % Ub > 65535
    encode_length(undefined,Len);
encode_length({Vr={Lb,Ub},Ext},Len) 
  when Ub =< 65535 ,Lb >= 0,Len=<Ub, is_list(Ext) -> 
    %% constrained extensible 
    [0,encode_constrained_number(Vr,Len)];
encode_length({{Lb,_},Ext},Len) when is_list(Ext) -> 
    [1,encode_semi_constrained_number(Lb,Len)];
encode_length(SingleValue,_Len) when is_integer(SingleValue) ->
    [].

%% X.691 10.9.3.4 (only used for length of bitmap that prefixes extension 
%% additions in a sequence or set
encode_small_length(Len) when Len =< 64 ->
%%    [{bits,1,0},{bits,6,Len-1}];
%    {bits,7,Len-1}; % the same as above but more efficient
    [10,7,Len-1];
encode_small_length(Len) ->
%    [{bits,1,1},encode_length(undefined,Len)].
    [1,encode_length(undefined,Len)].


decode_length(Buffer,undefined)  -> % un-constrained
    case align(Buffer) of
	<<0:1,Oct:7,Rest/binary>> ->
	    {Oct,Rest};
	<<2:2,Val:14,Rest/binary>> ->
	    {Val,Rest};
	<<3:2,_Val:14,_Rest/binary>> ->
	    %% this case should be fixed
	    exit({error,{asn1,{decode_length,{nyi,above_16k}}}})
    end;

decode_length(Buffer,{Lb,Ub}) when Ub =< 65535 ,Lb >= 0 -> % constrained
    decode_constrained_number(Buffer,{Lb,Ub});
decode_length(Buffer,{Lb,_Ub}) when is_integer(Lb), Lb >= 0 -> % Ub > 65535
    decode_length(Buffer,undefined);
decode_length(Buffer,{{Lb,Ub},Ext}) when is_list(Ext) -> 
    case getbit(Buffer) of
	{0,Buffer2} ->
	    decode_length(Buffer2, {Lb,Ub});
	{1,Buffer2} ->
	    decode_length(Buffer2, undefined)
    end;


%When does this case occur with {_,_Lb,Ub} ??
% X.691:10.9.3.5 
decode_length(Bin,{_,_Lb,_Ub}) -> % Unconstrained or large Ub NOTE! this case does not cover case when Ub > 65535
    case Bin of
	<<0:1,Val:7,Rest/bitstring>> -> 
	    {Val,Rest};
	_ ->
	    case align(Bin) of
		<<2:2,Val:14,Rest/binary>> -> 
		    {Val,Rest};
		<<3:2,_:14,_Rest/binary>> -> 
		    exit({error,{asn1,{decode_length,{nyi,length_above_64K}}}})
	    end
    end;
decode_length(Buffer,SingleValue) when is_integer(SingleValue) ->
    {SingleValue,Buffer}.



%%===============================================================================
%%===============================================================================
%%===============================================================================
%% Bitstring value, ITU_T X.690 Chapter 8.5
%%===============================================================================
%%===============================================================================
%%===============================================================================

%%===============================================================================
%% encode bitstring value
%%===============================================================================



%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% bitstring NamedBitList
%% Val can be  of:
%% - [identifiers] where only named identifers are set to one, 
%%   the Constraint must then have some information of the 
%%   bitlength.
%% - [list of ones and zeroes] all bits 
%% - integer value representing the bitlist
%% C is constraint Len, only valid when identifiers


%% when the value is a list of {Unused,BinBits}, where 
%% Unused = integer(),
%% BinBits = binary().

encode_bit_string(C,Bin={Unused,BinBits},NamedBitList) when is_integer(Unused),
							    is_binary(BinBits) ->
    encode_bin_bit_string(C,Bin,NamedBitList);

%% when the value is a list of named bits

encode_bit_string(C, LoNB=[FirstVal | _RestVal], NamedBitList) when is_atom(FirstVal) ->
    ToSetPos = get_all_bitposes(LoNB, NamedBitList, []),
    BitList = make_and_set_list(ToSetPos,0),
    encode_bit_string(C,BitList,NamedBitList);% consider the constraint

encode_bit_string(C, BL=[{bit,_} | _RestVal], NamedBitList) ->
    ToSetPos = get_all_bitposes(BL, NamedBitList, []),
    BitList = make_and_set_list(ToSetPos,0),
    encode_bit_string(C,BitList,NamedBitList);

%% when the value is a list of ones and zeroes
encode_bit_string(Int, BitListValue, _) 
  when is_list(BitListValue),is_integer(Int),Int =< 16 ->
    %% The type is constrained by a single value size constraint
    %% range_check(Int,length(BitListValue)),
    [40,Int,length(BitListValue),BitListValue];
encode_bit_string(Int, BitListValue, _) 
  when is_list(BitListValue),is_integer(Int), Int =< 255 ->
    %% The type is constrained by a single value size constraint
    %% range_check(Int,length(BitListValue)),
    [2,40,Int,length(BitListValue),BitListValue];
encode_bit_string(Int, BitListValue, _) 
  when is_list(BitListValue),is_integer(Int), Int < ?'64K' ->
    {Code,DesiredLength,Length} = 
	case length(BitListValue) of
	    B1 when B1 > Int ->
		exit({error,{'BIT_STRING_length_greater_than_SIZE',
			     Int,BitListValue}});
	    B1 when B1 =< 255,Int =< 255 ->
		{40,Int,B1};
	    B1 when B1 =< 255 ->
		{42,<<Int:16>>,B1};
	    B1 ->
		{43,<<Int:16>>,<<B1:16>>}
	end,
    %% The type is constrained by a single value size constraint
    [2,Code,DesiredLength,Length,BitListValue];
encode_bit_string(no, BitListValue,[]) 
  when is_list(BitListValue) ->
    [encode_length(undefined,length(BitListValue)),
     2,BitListValue];
encode_bit_string({{Fix,Fix},Ext}, BitListValue,[]) 
  when is_integer(Fix), is_list(Ext) ->
    case length(BitListValue) of
	Len when Len =< Fix ->
	    [0,encode_bit_string(Fix,BitListValue,[])];
	_ ->
	    [1,encode_bit_string(no,BitListValue,[])]
    end;
encode_bit_string(C, BitListValue,[]) 
  when is_list(BitListValue) ->
    [encode_length(C,length(BitListValue)),
     2,BitListValue];
encode_bit_string(no, BitListValue,_NamedBitList) 
  when is_list(BitListValue) ->
    %% this case with an unconstrained BIT STRING can be made more efficient
    %% if the complete driver can take a special code so the length field
    %% is encoded there.
    NewBitLVal = lists:reverse(lists:dropwhile(fun(0)->true;(1)->false end,
					    lists:reverse(BitListValue))),
    [encode_length(undefined,length(NewBitLVal)),
     2,NewBitLVal];
encode_bit_string({{Fix,Fix},Ext}, BitListValue,_NamedBitList) 
  when is_integer(Fix), is_list(Ext) ->
    case length(BitListValue) of
	Len when Len =< Fix ->
	    [0,encode_bit_string(Fix,BitListValue,_NamedBitList)];
	_ ->
	    [1,encode_bit_string(no,BitListValue,_NamedBitList)]
    end;
encode_bit_string(C,BitListValue,_NamedBitList) 
  when is_list(BitListValue) ->% C = {_,'MAX'}
%     NewBitLVal = lists:reverse(lists:dropwhile(fun(0)->true;(1)->false end,
% 					    lists:reverse(BitListValue))),
    NewBitLVal = bit_string_trailing_zeros(BitListValue,C),
    [encode_length(C,length(NewBitLVal)),
     2,NewBitLVal]; 


%% when the value is an integer
encode_bit_string(C, IntegerVal, NamedBitList) when is_integer(IntegerVal)->
    BitList = int_to_bitlist(IntegerVal),
    encode_bit_string(C,BitList,NamedBitList);

%% when the value is a tuple
encode_bit_string(C,{Name,Val}, NamedBitList) when is_atom(Name) ->
    encode_bit_string(C,Val,NamedBitList).

bit_string_trailing_zeros(BitList,C) when is_integer(C) ->
    bit_string_trailing_zeros1(BitList,C,C);
bit_string_trailing_zeros(BitList,{Lb,Ub}) when is_integer(Lb) ->
    bit_string_trailing_zeros1(BitList,Lb,Ub);
bit_string_trailing_zeros(BitList,{{Lb,Ub},_}) when is_integer(Lb) ->
    bit_string_trailing_zeros1(BitList,Lb,Ub);
bit_string_trailing_zeros(BitList,_) ->
    BitList.

bit_string_trailing_zeros1(BitList,Lb,Ub) ->
    case length(BitList) of
	Lb -> BitList;
	B when B<Lb -> BitList++lists:duplicate(Lb-B,0);
	D -> F = fun(L,LB,LB,_,_)->lists:reverse(L);
		    ([0|R],L1,LB,UB,Fun)->Fun(R,L1-1,LB,UB,Fun);
		    (L,L1,_,UB,_)when L1 =< UB -> lists:reverse(L);
		    (_,_L1,_,_,_) ->exit({error,{list_length_BIT_STRING,
						 BitList}}) end,
	     F(lists:reverse(BitList),D,Lb,Ub,F)
    end.

%% encode_bin_bit_string/3, when value is a tuple of Unused and BinBits.
%% Unused = integer(),i.e. number unused bits in least sign. byte of
%% BinBits = binary().
encode_bin_bit_string(C,{Unused,BinBits},_NamedBitList)
  when is_integer(C),C=<16 ->
    range_check(C,bit_size(BinBits) - Unused),
    [45,C,size(BinBits),BinBits];
encode_bin_bit_string(C,{Unused,BinBits},_NamedBitList)
  when is_integer(C), C =< 255 ->
    range_check(C,bit_size(BinBits) - Unused),
    [2,45,C,size(BinBits),BinBits];
encode_bin_bit_string(C,{Unused,BinBits},_NamedBitList)
  when is_integer(C), C =< 65535 ->
    range_check(C,bit_size(BinBits) - Unused),
    case size(BinBits) of
	Size when Size =< 255 ->
	    [2,46,<<C:16>>,Size,BinBits];
	Size ->
	    [2,47,<<C:16>>,<<Size:16>>,BinBits]
    end;
%% encode_bin_bit_string(C,{_Unused,BinBits},_NamedBitList)
%%   when is_integer(C) ->
%%     exit({error,{asn1, {bitstring_size, not_supported, C}}});
encode_bin_bit_string(C,UnusedAndBin={_,_},NamedBitList) ->
%    UnusedAndBin1 = {Unused1,Bin1} = 
    {Unused1,Bin1} = 
	%% removes all trailing bits if NamedBitList is not empty
	remove_trailing_bin(NamedBitList,UnusedAndBin),
    case C of
	{Lb,Ub} when is_integer(Lb),is_integer(Ub) ->
%	    [encode_length({Lb,Ub},size(Bin1)*8 - Unused1),
%	     align,UnusedAndBin1];
	    Size=size(Bin1),
	    [encode_length({Lb,Ub},Size*8 - Unused1),
	     2,octets_unused_to_complete(Unused1,Size,Bin1)];
	no ->
	    Size=size(Bin1),
	    [encode_length(undefined,Size*8 - Unused1),
	     2,octets_unused_to_complete(Unused1,Size,Bin1)];
	{{Fix,Fix},Ext} when is_integer(Fix),is_list(Ext) ->
	    %%[encode_length(Sc,size(Bin1)*8 - Unused1),
	    case size(Bin1)*8 - Unused1 of
		Size when Size =< Fix  ->
		    [0,encode_bin_bit_string(Fix,UnusedAndBin,NamedBitList)];
		_Size ->
		    [1,encode_bin_bit_string(no,UnusedAndBin,NamedBitList)]
	    end;
	Sc -> 
	    Size=size(Bin1),
	    [encode_length(Sc,Size*8 - Unused1),
	     2,octets_unused_to_complete(Unused1,Size,Bin1)]
    end.

range_check(C,C) when is_integer(C) ->
    ok;
range_check(C1,C2) when is_integer(C1) ->
    exit({error,{asn1,{bit_string_out_of_range,{C1,C2}}}}).

remove_trailing_bin([], {Unused,Bin}) ->
    {Unused,Bin};
remove_trailing_bin(_NamedNumberList,{_Unused,<<>>}) ->
    {0,<<>>};
remove_trailing_bin(NamedNumberList, {_Unused,Bin}) ->
    Size = size(Bin)-1,
    <<Bfront:Size/binary, LastByte:8>> = Bin,
    %% clear the Unused bits to be sure
%    LastByte1 = LastByte band (((1 bsl Unused) -1) bxor 255),% why this???
    Unused1 = trailingZeroesInNibble(LastByte band 15),
    Unused2 = 
	case Unused1 of 
	    4 ->
		4 + trailingZeroesInNibble(LastByte bsr 4);
	    _ -> Unused1
	end,
    case Unused2 of
	8 ->
	    remove_trailing_bin(NamedNumberList,{0,Bfront});
	_ ->
	    {Unused2,Bin}
    end.


trailingZeroesInNibble(0) ->
    4;
trailingZeroesInNibble(1) ->
    0;
trailingZeroesInNibble(2) ->
    1;
trailingZeroesInNibble(3) ->
    0;
trailingZeroesInNibble(4) ->
    2;
trailingZeroesInNibble(5) ->
    0;
trailingZeroesInNibble(6) ->
    1;
trailingZeroesInNibble(7) ->
    0;
trailingZeroesInNibble(8) ->
    3;
trailingZeroesInNibble(9) ->
    0;
trailingZeroesInNibble(10) ->
    1;
trailingZeroesInNibble(11) ->
    0;
trailingZeroesInNibble(12) -> %#1100
    2;
trailingZeroesInNibble(13) ->
    0;
trailingZeroesInNibble(14) ->
    1;
trailingZeroesInNibble(15) ->
    0.

%%%%%%%%%%%%%%%
%% The result is presented as a list of named bits (if possible)
%% else as a tuple {Unused,Bits}. Unused is the number of unused
%% bits, least significant bits in the last byte of Bits. Bits is
%% the BIT STRING represented as a binary.
%% 
decode_compact_bit_string(Buffer, C, NamedNumberList) ->
    case get_constraint(C,'SizeConstraint') of
	0 -> % fixed length
	    {{8,0},Buffer};
	V when is_integer(V),V=<16 -> %fixed length 16 bits or less
	    compact_bit_string(Buffer,V,NamedNumberList);
	V when is_integer(V),V=<65536 -> %fixed length > 16 bits
	    Bytes2 = align(Buffer),
	    compact_bit_string(Bytes2,V,NamedNumberList);
	V when is_integer(V) -> % V > 65536 => fragmented value
	    {BitStr,Buffer2} = decode_fragmented_bits(Buffer,V),
	    case bit_size(BitStr) band 7 of
		0 -> {{0,BitStr},Buffer2};
		N -> {{8-N,<<BitStr/bitstring,0:(8-N)>>},Buffer2}
	    end;
	{Lb,Ub} when is_integer(Lb),is_integer(Ub) ->
	    %% This case may demand decoding of fragmented length/value
	    {Len,Bytes2} = decode_length(Buffer,{Lb,Ub}),
	    Bytes3 = align(Bytes2),
	    compact_bit_string(Bytes3,Len,NamedNumberList);
	no ->
	    %% This case may demand decoding of fragmented length/value
	    {Len,Bytes2} = decode_length(Buffer,undefined),
	    Bytes3 = align(Bytes2),
	    compact_bit_string(Bytes3,Len,NamedNumberList);
	{{Fix,Fix},Ext} = Sc when is_integer(Fix), is_list(Ext) ->
	    case decode_length(Buffer,Sc) of
		{Len,Bytes2} when Len > Fix ->
		    Bytes3 = align(Bytes2),
		    compact_bit_string(Bytes3,Len,NamedNumberList);
		{Len,Bytes2} when Len > 16 ->
		    Bytes3 = align(Bytes2),
		    compact_bit_string(Bytes3,Len,NamedNumberList);
		{Len,Bytes2} ->
		    compact_bit_string(Bytes2,Len,NamedNumberList)
	    end;
	Sc ->
	    {Len,Bytes2} = decode_length(Buffer,Sc),
	    Bytes3 = align(Bytes2),
	    compact_bit_string(Bytes3,Len,NamedNumberList)
    end.


%%%%%%%%%%%%%%%
%% The result is presented as a list of named bits (if possible)
%% else as a list of 0 and 1.
%% 
decode_bit_string(Buffer, C, NamedNumberList) ->
    case get_constraint(C,'SizeConstraint') of
	{Lb,Ub} when is_integer(Lb),is_integer(Ub) ->
	    {Len,Bytes2} = decode_length(Buffer,{Lb,Ub}),
	    Bytes3 = align(Bytes2),
	    bit_list_or_named(Bytes3,Len,NamedNumberList);
	no ->
	    {Len,Bytes2} = decode_length(Buffer,undefined),
	    Bytes3 = align(Bytes2),
	    bit_list_or_named(Bytes3,Len,NamedNumberList);
	0 -> % fixed length
	    {[],Buffer}; % nothing to encode
	V when is_integer(V),V=<16 -> % fixed length 16 bits or less
	    bit_list_or_named(Buffer,V,NamedNumberList);
	V when is_integer(V),V=<65536 ->
	    Bytes2 = align(Buffer),
	    bit_list_or_named(Bytes2,V,NamedNumberList);
	V when is_integer(V) ->
	    Bytes2 = align(Buffer),
	    {BinBits,_Bytes3} = decode_fragmented_bits(Bytes2,V),
	    bit_list_or_named(BinBits,V,NamedNumberList);
	{{Fix,Fix},Ext} =Sc when is_integer(Fix), is_list(Ext) ->
	    case decode_length(Buffer,Sc) of
		{Len,Bytes2} when Len > Fix ->
		    Bytes3 = align(Bytes2),
		    bit_list_or_named(Bytes3,Len,NamedNumberList);
		{Len,Bytes2} when Len > 16 ->
		    Bytes3 = align(Bytes2),
		    bit_list_or_named(Bytes3,Len,NamedNumberList);
		{Len,Bytes2} ->
		    bit_list_or_named(Bytes2,Len,NamedNumberList)
	    end;
	Sc -> % extension marker
	    {Len,Bytes2} = decode_length(Buffer,Sc),
	    Bytes3 = align(Bytes2),
	    bit_list_or_named(Bytes3,Len,NamedNumberList)
    end.


%% if no named bits are declared we will return a
%% {Unused,Bits}. Unused = integer(),
%% Bits = binary().
compact_bit_string(Buffer,Len,[]) ->
    {BitStr,Rest} = getbits_as_binary(Len,Buffer), % {{Unused,BinBits},NewBuffer}
    PadLen = (8 - (bit_size(BitStr) rem 8)) rem 8,
    {{PadLen,<<BitStr/bitstring,0:PadLen>>},Rest};
compact_bit_string(Buffer,Len,NamedNumberList) ->
    bit_list_or_named(Buffer,Len,NamedNumberList).


%% if no named bits are declared we will return a
%% BitList = [0 | 1]

bit_list_or_named(Buffer,Len,[]) ->
    getbits_as_list(Len,Buffer);

%% if there are named bits declared we will return a named
%% BitList where the names are atoms and unnamed bits represented
%% as {bit,Pos}
%% BitList = [atom() | {bit,Pos}]
%% Pos = integer()

bit_list_or_named(Buffer,Len,NamedNumberList) ->
    {BitList,Rest} = getbits_as_list(Len,Buffer),
    {bit_list_or_named1(0,BitList,NamedNumberList,[]), Rest}.

bit_list_or_named1(Pos,[0|Bt],Names,Acc) ->
    bit_list_or_named1(Pos+1,Bt,Names,Acc);
bit_list_or_named1(Pos,[1|Bt],Names,Acc) ->
    case lists:keysearch(Pos,2,Names) of
	{value,{Name,_}} ->
	    bit_list_or_named1(Pos+1,Bt,Names,[Name|Acc]);
	_  -> 
	    bit_list_or_named1(Pos+1,Bt,Names,[{bit,Pos}|Acc])
    end;
bit_list_or_named1(_Pos,[],_Names,Acc) ->
    lists:reverse(Acc).



%%%%%%%%%%%%%%%
%% 

int_to_bitlist(Int) when is_integer(Int), Int > 0 ->
    [Int band 1 | int_to_bitlist(Int bsr 1)];
int_to_bitlist(0) ->
    [].


%%%%%%%%%%%%%%%%%%
%% get_all_bitposes([list of named bits to set], named_bit_db, []) ->
%%   [sorted_list_of_bitpositions_to_set]

get_all_bitposes([{bit,ValPos}|Rest], NamedBitList, Ack) ->
    get_all_bitposes(Rest, NamedBitList, [ValPos | Ack ]);

get_all_bitposes([Val | Rest], NamedBitList, Ack) ->
    case lists:keysearch(Val, 1, NamedBitList) of
	{value, {_ValName, ValPos}} ->
	    get_all_bitposes(Rest, NamedBitList, [ValPos | Ack]);
	_ ->
	    exit({error,{asn1, {bitstring_namedbit, Val}}})
    end;
get_all_bitposes([], _NamedBitList, Ack) ->
    lists:sort(Ack).

%%%%%%%%%%%%%%%%%%
%% make_and_set_list([list of positions to set to 1])->
%% returns list with all in SetPos set.
%% in positioning in list the first element is 0, the second 1 etc.., but
%% 

make_and_set_list([XPos|SetPos], XPos) ->
    [1 | make_and_set_list(SetPos, XPos + 1)];
make_and_set_list([Pos|SetPos], XPos) ->
    [0 | make_and_set_list([Pos | SetPos], XPos + 1)];
make_and_set_list([], _) ->
    [].



%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% X.691:16
%% encode_octet_string(Constraint,ExtensionMarker,Val)
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

encode_octet_string(C,Val) ->
    encode_octet_string(C,false,Val).

encode_octet_string(C,Bool,{_Name,Val}) ->
    encode_octet_string(C,Bool,Val);
encode_octet_string(_C,true,_Val) -> 
    exit({error,{asn1,{'not_supported',extensionmarker}}});
encode_octet_string(SZ={_,_},false,Val) ->
%    [encode_length(SZ,length(Val)),align,
%	     {octets,Val}];
    Len = length(Val),
    try
	[encode_length(SZ,Len),2,
	 octets_to_complete(Len,Val)]
    catch
	exit:{error,{asn1,{encode_length,_}}} ->
	    encode_fragmented_octet_string(Val)
    end;
encode_octet_string(SZ,false,Val) when is_list(SZ) ->
    Len = length(Val),
    try
	[encode_length({hd(SZ),lists:max(SZ)},Len),2,
	 octets_to_complete(Len,Val)]
    catch
	exit:{error,{asn1,{encode_length,_}}} ->
	    encode_fragmented_octet_string(Val)
    end;
encode_octet_string(Sv,false,Val) when is_integer(Sv) ->
    encode_fragmented_octet_string(Val);
encode_octet_string(no,false,Val) ->
    Len = length(Val),
    try
	[encode_length(undefined,Len),2,
	 octets_to_complete(Len,Val)]
    catch
	exit:{error,{asn1,{encode_length,_}}} ->
	    encode_fragmented_octet_string(Val)
    end;
encode_octet_string(C,_,_) ->
    exit({error,{not_implemented,C}}).

encode_fragmented_octet_string(Val) ->
    Bin = iolist_to_binary(Val),
    efos_1(Bin).

efos_1(<<B1:16#C000/binary,B2:16#4000/binary,T/binary>>) ->
    [20,1,<<3:2,4:6>>,
     octets_to_complete(16#C000, B1),
     octets_to_complete(16#4000, B2)|efos_1(T)];
efos_1(<<B:16#C000/binary,T/binary>>) ->
    [20,1,<<3:2,3:6>>,octets_to_complete(16#C000, B)|efos_1(T)];
efos_1(<<B:16#8000/binary,T/binary>>) ->
    [20,1,<<3:2,2:6>>,octets_to_complete(16#8000, B)|efos_1(T)];
efos_1(<<B:16#4000/binary,T/binary>>) ->
    [20,1,<<3:2,1:6>>,octets_to_complete(16#4000, B)|efos_1(T)];
efos_1(<<>>) ->
    [20,1,0];
efos_1(<<B/bitstring>>) ->
    Len = byte_size(B),
    [encode_length(undefined, Len),octets_to_complete(Len, B)].

decode_fragmented(SegSz0, Buf0, Unit) ->
    SegSz = SegSz0 * Unit * ?'16K',
    <<Res:SegSz/bitstring,Buf/bitstring>> = Buf0,
    decode_fragmented_1(Buf, Unit, Res).

decode_fragmented_1(<<0:1,N:7,Buf0/bitstring>>, Unit, Res) ->
    Sz = N*Unit,
    <<S:Sz/bitstring,Buf/bitstring>> = Buf0,
    {<<Res/bitstring,S/bitstring>>,Buf};
decode_fragmented_1(<<1:1,0:1,N:14,Buf0/bitstring>>, Unit, Res) ->
    Sz = N*Unit,
    <<S:Sz/bitstring,Buf/bitstring>> = Buf0,
    {<<Res/bitstring,S/bitstring>>,Buf};
decode_fragmented_1(<<1:1,1:1,SegSz0:6,Buf0/bitstring>>, Unit, Res0) ->
    SegSz = SegSz0 * Unit * ?'16K',
    <<Frag:SegSz/bitstring,Buf/bitstring>> = Buf0,
    Res = <<Res0/bitstring,Frag/bitstring>>,
    decode_fragmented_1(Buf, Unit, Res).


%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% Restricted char string types 
%% (NumericString, PrintableString,VisibleString,IA5String,BMPString,UniversalString)
%% X.691:26 and X.680:34-36
%%encode_restricted_string(aligned,'BMPString',Constraints,Extension,Val)


encode_restricted_string(aligned,{Name,Val}) when is_atom(Name) ->
    encode_restricted_string(aligned,Val);

encode_restricted_string(aligned,Val) when is_list(Val)->
    Len = length(Val),
    [encode_length(undefined,Len),octets_to_complete(Len,Val)].


encode_known_multiplier_string(StringType,SizeC,NumBits,CharOutTab,{Name,Val}) when is_atom(Name) ->
    encode_known_multiplier_string(StringType,SizeC,NumBits,CharOutTab,Val);
encode_known_multiplier_string(_StringType,SizeC,NumBits,CharOutTab,Val) ->
    Result = chars_encode2(Val,NumBits,CharOutTab),
    case SizeC of
	Ub when is_integer(Ub), Ub*NumBits =< 16  ->
	    Result;
	Ub when is_integer(Ub),Ub =<65535 -> % fixed length
	    [2,Result];
	{Ub,Lb} ->
	    [encode_length({Ub,Lb},length(Val)),2,Result];
	no  ->
	    [encode_length(undefined,length(Val)),2,Result]
    end.

decode_restricted_string(Bytes,aligned) ->
    {Len,Bytes2} = decode_length(Bytes,undefined),
    getoctets_as_list(Bytes2,Len).

decode_known_multiplier_string(StringType,SizeC,NumBits,CharInTab,Bytes) ->
    case SizeC of
	Ub when is_integer(Ub), Ub*NumBits =< 16  ->
	    chars_decode(Bytes,NumBits,StringType,CharInTab,Ub);
	Ub when is_integer(Ub),Ub =<65535 -> % fixed length
	    Bytes1 = align(Bytes),
	    chars_decode(Bytes1,NumBits,StringType,CharInTab,Ub);
	Vl when is_list(Vl) ->
	    {Len,Bytes1} = decode_length(Bytes,{hd(Vl),lists:max(Vl)}),
	    Bytes2 = align(Bytes1),
	    chars_decode(Bytes2,NumBits,StringType,CharInTab,Len);
	no  ->
	    {Len,Bytes1} = decode_length(Bytes,undefined),
	    Bytes2 = align(Bytes1),
	    chars_decode(Bytes2,NumBits,StringType,CharInTab,Len);
	{Lb,Ub}->
	    {Len,Bytes1} = decode_length(Bytes,{Lb,Ub}),
	    Bytes2 = align(Bytes1),
	    chars_decode(Bytes2,NumBits,StringType,CharInTab,Len)
    end.

encode_GeneralString(_C,Val) ->
    encode_restricted_string(aligned,Val).
decode_GeneralString(Bytes,_C) ->
    decode_restricted_string(Bytes,aligned).

encode_GraphicString(_C,Val) ->
    encode_restricted_string(aligned,Val).
decode_GraphicString(Bytes,_C) ->
    decode_restricted_string(Bytes,aligned).

encode_ObjectDescriptor(_C,Val) ->
    encode_restricted_string(aligned,Val).
decode_ObjectDescriptor(Bytes) ->
    decode_restricted_string(Bytes,aligned).

encode_TeletexString(_C,Val) -> % equivalent with T61String
    encode_restricted_string(aligned,Val).
decode_TeletexString(Bytes,_C) ->
    decode_restricted_string(Bytes,aligned).

encode_VideotexString(_C,Val) ->
    encode_restricted_string(aligned,Val).
decode_VideotexString(Bytes,_C) ->
    decode_restricted_string(Bytes,aligned).




%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% getBMPChars(Bytes,Len) ->{BMPcharList,RemainingBytes}
%%
getBMPChars(<<T/binary>>, 0, Acc) ->
    {lists:reverse(Acc),T};
getBMPChars(<<0,O2,Bytes1/bitstring>>, Len, Acc) ->
    getBMPChars(Bytes1,Len-1,[O2|Acc]);
getBMPChars(<<O1,O2,Bytes1/bitstring>>, Len, Acc) ->
    getBMPChars(Bytes1,Len-1,[{0,0,O1,O2}|Acc]).

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% chars_encode(C,StringType,Value) -> ValueList
%%
%% encodes chars according to the per rules taking the constraint PermittedAlphabet 
%% into account.
%% This function does only encode the value part and NOT the length

% chars_encode(C,StringType,Value) ->
%     case {StringType,get_constraint(C,'PermittedAlphabet')} of
% 	{'UniversalString',{_,Sv}} ->
% 	    exit({error,{asn1,{'not implemented',"UniversalString with PermittedAlphabet constraint"}}});
% 	{'BMPString',{_,Sv}} ->
% 	    exit({error,{asn1,{'not implemented',"BMPString with PermittedAlphabet constraint"}}});
% 	_ ->
% 	    {NumBits,CharOutTab} = {get_NumBits(C,StringType),get_CharOutTab(C,StringType)}, 
% 	    chars_encode2(Value,NumBits,CharOutTab)
%     end.


chars_encode2([H|T],NumBits,T1={Min,Max,notab}) when  H =< Max, H >= Min ->
%    [[10,NumBits,H-Min]|chars_encode2(T,NumBits,T1)];
    [pre_complete_bits(NumBits,H-Min)|chars_encode2(T,NumBits,T1)];
chars_encode2([H|T],NumBits,T1={Min,Max,Tab}) when H =< Max, H >= Min ->
%    [[10,NumBits,element(H-Min+1,Tab)]|chars_encode2(T,NumBits,T1)];
    [pre_complete_bits(NumBits,exit_if_false(H,element(H-Min+1,Tab)))|
     chars_encode2(T,NumBits,T1)];
chars_encode2([{A,B,C,D}|T],NumBits,T1={Min,_Max,notab}) -> 
    %% no value range check here (ought to be, but very expensive)
%    [{bits,NumBits,(A*B*C*D)-Min}|chars_encode2(T,NumBits,{Min,Max,notab})];
%    [[10,NumBits,((((((A bsl 8)+B) bsl 8)+C) bsl 8)+D)-Min]|chars_encode2(T,NumBits,T1)];
    [pre_complete_bits(NumBits,
			       ((((((A bsl 8)+B) bsl 8)+C) bsl 8)+D)-Min)|
     chars_encode2(T,NumBits,T1)];
chars_encode2([H={A,B,C,D}|T],NumBits,{Min,Max,Tab}) -> 
    %% no value range check here (ought to be, but very expensive)
    [pre_complete_bits(NumBits,exit_if_false(H,element(((((((A bsl 8)+B) bsl 8)+C) bsl 8)+D)-Min,Tab)))|chars_encode2(T,NumBits,{Min,Max,notab})];
chars_encode2([H|_T],_NumBits,{_Min,_Max,_Tab}) ->
    exit({error,{asn1,{illegal_char_value,H}}});
chars_encode2([],_,_) ->
    [].

exit_if_false(V,false)->
    exit({error,{asn1,{"illegal value according to Permitted alphabet constraint",V}}});
exit_if_false(_,V) ->V.

pre_complete_bits(NumBits,Val) when NumBits =< 8 ->
    [10,NumBits,Val];
pre_complete_bits(NumBits,Val) when NumBits =< 16 ->
    [10,NumBits-8,Val bsr 8,10,8,(Val band 255)];
pre_complete_bits(NumBits,Val) when NumBits =< 2040 -> % 255 * 8
%     LBUsed = NumBits rem 8,
%     {Unused,Len} = case (8 - LBUsed) of
% 		       8 -> {0,NumBits div 8};
% 		       U -> {U,(NumBits div 8) + 1}
% 		   end,
%     NewVal = Val bsr LBUsed,
%     [30,Unused,Len,<<NewVal:Len/unit:8,Val:LBUsed,0:Unused>>].
    Unused = (8 - (NumBits rem 8)) rem 8,
    Len = NumBits + Unused,
    [30,Unused,Len div 8,<<(Val bsl Unused):Len>>].


chars_decode(Bytes,_,'BMPString',_,Len) ->
    getBMPChars(Bytes,Len,[]);
chars_decode(Bytes,NumBits,_StringType,CharInTab,Len) ->	
    chars_decode2(Bytes,CharInTab,NumBits,Len).


chars_decode2(Bytes,CharInTab,NumBits,Len) ->
    chars_decode2(Bytes,CharInTab,NumBits,Len,[]).

chars_decode2(Bytes,_CharInTab,_NumBits,0,Acc) ->
    {lists:reverse(Acc),Bytes};
chars_decode2(Bytes,{Min,Max,notab},NumBits,Len,Acc) when NumBits > 8 ->
    {Char,Bytes2} = getbits(Bytes,NumBits),
    Result = 
	if
	    Char < 256 -> Char;
	    true ->
		list_to_tuple(binary_to_list(<<Char:32>>))
	end,
    chars_decode2(Bytes2,{Min,Max,notab},NumBits,Len -1,[Result|Acc]);
chars_decode2(Bytes,{Min,Max,notab},NumBits,Len,Acc) ->
    {Char,Bytes2} = getbits(Bytes,NumBits),
    chars_decode2(Bytes2,{Min,Max,notab},NumBits,Len -1,[Char+Min|Acc]);

%% BMPString and UniversalString with PermittedAlphabet is currently not supported
chars_decode2(Bytes,{Min,Max,CharInTab},NumBits,Len,Acc) ->
    {Char,Bytes2} = getbits(Bytes,NumBits),
    chars_decode2(Bytes2,{Min,Max,CharInTab},NumBits,Len -1,[element(Char+1,CharInTab)|Acc]).


%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% encode_UTF8String(Val) -> CompleteList
%% Val -> <<utf8encoded binary>>
%% CompleteList -> [apropriate codes and values for driver complete]
%%
encode_UTF8String(Val) when is_binary(Val) ->
    [encode_length(undefined,size(Val)),
     octets_to_complete(size(Val),Val)];
encode_UTF8String(Val) ->
    encode_UTF8String(list_to_binary(Val)).


%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% decode_UTF8String(Bytes) -> {Utf8Binary,RemainingBytes}
%% Utf8Binary -> <<utf8 encoded binary>>
%% RemainingBytes -> <<buffer>>
decode_UTF8String(Bytes) -> 
    {Len,Bytes2} = decode_length(Bytes,undefined),
    {_Bin,_Bytes3} = getoctets_as_bin(Bytes2,Len).




%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% encode_object_identifier(Val) -> CompleteList
%% encode_object_identifier({Name,Val}) -> CompleteList
%% Val -> {Int1,Int2,...,IntN} % N >= 2
%% Name -> atom()
%% Int1 -> integer(0..2)
%% Int2 -> integer(0..39) when Int1 (0..1) else integer()
%% Int3-N -> integer()
%% CompleteList -> [{bits,8,Val}|{octets,Ol}|align|...]
%%
encode_object_identifier({Name,Val}) when is_atom(Name) ->
    encode_object_identifier(Val);
encode_object_identifier(Val) ->
    OctetList = e_object_identifier(Val),
    Octets = list_to_binary(OctetList),
    [encode_length(undefined,size(Octets)),
     octets_to_complete(size(Octets),Octets)].

e_object_identifier({'OBJECT IDENTIFIER',V}) ->
    e_object_identifier(V);
e_object_identifier({Cname,V}) when is_atom(Cname),is_tuple(V) ->
    e_object_identifier(tuple_to_list(V));
e_object_identifier({Cname,V}) when is_atom(Cname),is_list(V) ->
    e_object_identifier(V);
e_object_identifier(V) when is_tuple(V) ->
    e_object_identifier(tuple_to_list(V));

%% E1 = 0|1|2 and (E2 < 40 when E1 = 0|1) 
e_object_identifier([E1,E2|Tail]) when E1 >= 0, E1 < 2, E2 < 40 ; E1==2 ->
    Head = 40*E1 + E2,  % weird
    e_object_elements([Head|Tail],[]);
e_object_identifier(Oid=[_,_|_Tail]) ->
    exit({error,{asn1,{'illegal_value',Oid}}}).

e_object_elements([],Acc) ->
    lists:reverse(Acc);
e_object_elements([H|T],Acc) ->
    e_object_elements(T,[e_object_element(H)|Acc]).

e_object_element(Num) when Num < 128 ->
    [Num];
e_object_element(Num) ->
    [e_o_e(Num bsr 7)|[Num band 2#1111111]].
e_o_e(Num) when Num < 128 ->
    Num bor 2#10000000;
e_o_e(Num) ->
    [e_o_e(Num bsr 7)|[(Num band 2#1111111) bor 2#10000000]].



%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% decode_object_identifier(Bytes) -> {ObjId,RemainingBytes}
%% ObjId -> {integer(),integer(),...} % at least 2 integers
%% RemainingBytes -> [integer()] when integer() (0..255)
decode_object_identifier(Bytes) ->
    {Len,Bytes2} = decode_length(Bytes,undefined),
    {Octs,Bytes3} = getoctets_as_list(Bytes2,Len),
    [First|Rest] = dec_subidentifiers(Octs,0,[]),
    Idlist = if
		 First < 40 ->
		     [0,First|Rest];
		 First < 80 ->
		     [1,First - 40|Rest];
		 true ->
		     [2,First - 80|Rest]
	     end,
    {list_to_tuple(Idlist),Bytes3}.

dec_subidentifiers([H|T],Av,Al) when H >=16#80 ->
    dec_subidentifiers(T,(Av bsl 7) + (H band 16#7F),Al);
dec_subidentifiers([H|T],Av,Al) ->
    dec_subidentifiers(T,0,[(Av bsl 7) + H |Al]);
dec_subidentifiers([],_Av,Al) ->
    lists:reverse(Al).

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% encode_relative_oid(Val) -> CompleteList
%% encode_relative_oid({Name,Val}) -> CompleteList
encode_relative_oid({Name,Val}) when is_atom(Name) ->
    encode_relative_oid(Val);
encode_relative_oid(Val) when is_tuple(Val) ->
    encode_relative_oid(tuple_to_list(Val));
encode_relative_oid(Val) when is_list(Val) ->
    Octets = list_to_binary([e_object_element(X)||X <- Val]),
    [encode_length(undefined,size(Octets)),
     octets_to_complete(size(Octets),Octets)].
    
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% decode_relative_oid(Val) -> CompleteList
%% decode_relative_oid({Name,Val}) -> CompleteList
decode_relative_oid(Bytes) ->
    {Len,Bytes2} = decode_length(Bytes,undefined),
    {Octs,Bytes3} = getoctets_as_list(Bytes2,Len),
    ObjVals = dec_subidentifiers(Octs,0,[]),
    {list_to_tuple(ObjVals),Bytes3}.


%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% encode_real(Val) -> CompleteList
%% encode_real({Name,Val}) -> CompleteList
encode_real({Name,Val}) when is_atom(Name) ->
    encode_real(Val);
encode_real(Real) ->
    {EncVal,Len} = ?RT_COMMON:encode_real([],Real),
    [encode_length(undefined,Len),octets_to_complete(size(EncVal),EncVal)].


%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% decode_real(Val) -> {REALvalue,Rest}
%% decode_real({Name,Val}) -> {REALvalue,Rest}
decode_real(Bytes) ->
    {Len,Bytes2} = decode_length(Bytes,undefined),
    {RealVal,Rest,Len} = ?RT_COMMON:decode_real(Bytes2,Len),
    {RealVal,Rest}.


get_constraint([{Key,V}],Key) ->
    V;
get_constraint([],_) ->
    no;
get_constraint(C,Key) ->
    case lists:keysearch(Key,1,C) of
	false ->
	    no;
	{value,{_,V}} -> 
	    V
    end.


%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% complete(InList) -> ByteList
%% Takes a coded list with bits and bytes and converts it to a list of bytes
%% Should be applied as the last step at encode of a complete ASN.1 type
%%

-ifdef(nodriver).

complete(L) ->
    erlang_complete(L).

-else.

%% asn1-1.7
complete(L) ->
    case asn1rt_nif:encode_per_complete(L) of
	{error, Reason} -> handle_error(Reason, L);
	Else when is_binary(Else) -> Else
    end.

handle_error([],_)->
    exit({error,{asn1,{"memory allocation problem in driver"}}});
handle_error($1,L) -> % error in complete in driver
    exit({error,{asn1,L}});
handle_error(ErrL,L) ->
    exit({error,{asn1,ErrL,L}}).

-endif.


octets_to_complete(Len,Val) when Len < 256 ->
    [20,Len,Val];
octets_to_complete(Len,Val) ->
    [21,<<Len:16>>,Val].

octets_unused_to_complete(Unused,Len,Val) when Len < 256 ->
    [30,Unused,Len,Val];
octets_unused_to_complete(Unused,Len,Val) ->
    [31,Unused,<<Len:16>>,Val].