Fix broken handling of default values for BIT STRINGs

For DER/PER/UPER, a value equal to the DEFAULT is not supposed to
be encoded.

BIT STRINGs values can be represented as Erlang terms in four
different ways: as an integer, as a list of zeroes and ones,
as a {Unused,Binary} tuple, or as an Erlang bitstring.

When encoding a BIT STRING, only certain representations of
BIT STRINGs values were recognized. All representations must
be recognized.

When decoding a DEFAULT value for a BIT STRING, the actual value
given in the decoding would be either an integer or a list
of zeroes and one (depending on how the literal was written in
the specification). We expect that the default value should be
in the same representation as any other BIT STRING value (i.e.
by default an Erlang bitstring, or a list if the 'legacy_bitstring'
option has been given, or as compact bitstring if 'compact_bitstring'
has been given).

1 files changed, 38 insertions, 6 deletions

diff --git a/lib/asn1/src/asn1ct_gen.erl b/lib/asn1/src/asn1ct_gen.erl
index 3452d29085..30d337635b 100644
--- a/lib/asn1/src/asn1ct_gen.erl
+++ b/lib/asn1/src/asn1ct_gen.erl
@@ -33,7 +33,9 @@
 	 insert_once/2,
 	 ct_gen_module/1,
 	 index2suffix/1,
-	 get_record_name_prefix/0]).
+	 get_record_name_prefix/0,
+	 conform_value/2,
+	 named_bitstring_value/2]).
 -export([pgen/5,
 	 mk_var/1, 
 	 un_hyphen_var/1]).
@@ -1485,8 +1487,14 @@ gen_prim_check_call(PrimType, Default, Element, Type) ->
 		  end,
 	    check_call(check_int, [Default,Element,{asis,NNL}]);
 	'BIT STRING' ->
-	    {_,NBL} = Type#type.def,
-	    check_call(check_bitstring, [Default,Element,{asis,NBL}]);
+	    case Type#type.def of
+		{_,[]} ->
+		    check_call(check_bitstring,
+			       [Default,Element]);
+		{_,[_|_]=NBL} ->
+		    check_call(check_named_bitstring,
+			       [Default,Element,{asis,NBL}])
+	    end;
 	'OCTET STRING' ->
 	    check_call(check_octetstring, [Default,Element]);
 	'NULL' ->
@@ -1640,9 +1648,33 @@ unify_if_string(PrimType) ->
 	Other -> Other
     end.
 
-
-	
-	
+conform_value(#type{def={'BIT STRING',[]}}, Bs) ->
+    case asn1ct:get_bit_string_format() of
+	compact when is_binary(Bs) ->
+	    {0,Bs};
+	compact when is_bitstring(Bs) ->
+	    Sz = bit_size(Bs),
+	    Unused = 8 - bit_size(Bs),
+	    {Unused,<<Bs:Sz/bits,0:Unused>>};
+	legacy ->
+	    [B || <<B:1>> <= Bs];
+	bitstring when is_bitstring(Bs) ->
+	    Bs
+    end;
+conform_value(_, Value) -> Value.
+
+named_bitstring_value(List, Names) ->
+    Int = lists:foldl(fun(N, A) ->
+			      {N,Pos} = lists:keyfind(N, 1, Names),
+			      A bor (1 bsl Pos)
+		      end, 0, List),
+    named_bitstring_value_1(<<>>, Int).
+
+named_bitstring_value_1(Bs, 0) ->
+    Bs;
+named_bitstring_value_1(Bs, Int) ->
+    B = Int band 1,
+    named_bitstring_value_1(<<Bs/bitstring,B:1>>, Int bsr 1).
 
 get_inner(A) when is_atom(A) -> A;    
 get_inner(Ext) when is_record(Ext,'Externaltypereference') -> Ext;