Teach the ASN.1 compiler the 'maps' option

When the 'maps' option is given, the SEQUENCE and SET types are
represented as maps instead of as records. Optional and default values
must be not be given as asn1_NOVALUE or asn1_DEFAULT in a map passed
to the M:encode/2 function; they must be omitted from the
map. Similarly, when decoding missing values will be omitted from the
map.

No .hrl files will be generated when the 'maps' options is used.
That means values in an ASN.1 module must be retrieved by calling the
appropriate function in generated module.

Since we one day hope to get rid of the options 'compact_bit_string',
'legacy_bit_string', and 'legacy_erlang_types', we will not allow them
to be combined with the 'maps' option.

1 files changed, 39 insertions, 2 deletions

diff --git a/lib/asn1/src/asn1ct_imm.erl b/lib/asn1/src/asn1ct_imm.erl
index 741d54c321..2ab848652e 100644
--- a/lib/asn1/src/asn1ct_imm.erl
+++ b/lib/asn1/src/asn1ct_imm.erl
@@ -37,9 +37,11 @@
 	 per_enc_open_type/2,
 	 per_enc_restricted_string/3,
 	 per_enc_small_number/2]).
--export([per_enc_extension_bit/2,per_enc_extensions/4,per_enc_optional/2]).
+-export([per_enc_extension_bit/2,per_enc_extensions/4,
+         per_enc_extensions_map/4,
+         per_enc_optional/2]).
 -export([per_enc_sof/5]).
--export([enc_absent/3,enc_append/1,enc_element/2]).
+-export([enc_absent/3,enc_append/1,enc_element/2,enc_maps_get/2]).
 -export([enc_cg/2]).
 -export([optimize_alignment/1,optimize_alignment/2,
 	 dec_slim_cg/2,dec_code_gen/2]).
@@ -349,6 +351,20 @@ per_enc_extensions(Val0, Pos0, NumBits, Aligned) when NumBits > 0 ->
 			['_'|Length ++ PutBits]]}],
 	 {var,"Extensions"}}].
 
+per_enc_extensions_map(Val0, Vars, Undefined, Aligned) ->
+    NumBits = length(Vars),
+    {B,[_Val,Bitmap]} = mk_vars(Val0, [bitmap]),
+    Length = per_enc_small_length(NumBits, Aligned),
+    PutBits = case NumBits of
+		  1 -> [{put_bits,1,1,[1]}];
+		  _ -> [{put_bits,Bitmap,NumBits,[1]}]
+	      end,
+    BitmapExpr = extensions_bitmap(Vars, Undefined),
+    B++[{assign,Bitmap,BitmapExpr},
+	{list,[{'cond',[[{eq,Bitmap,0}],
+			['_'|Length ++ PutBits]]}],
+	 {var,"Extensions"}}].
+
 per_enc_optional(Val, DefVals) when is_list(DefVals) ->
     Zero = {put_bits,0,1,[1]},
     One = {put_bits,1,1,[1]},
@@ -414,6 +430,13 @@ enc_element(N, Val0) ->
     {[],[Val,Dst]} = mk_vars(Val0, [element]),
     {[{call,erlang,element,[N,Val],Dst}],Dst}.
 
+enc_maps_get(N, Val0) ->
+    {[],[Val,Dst0]} = mk_vars(Val0, [element]),
+    {var,Dst} = Dst0,
+    DstExpr = {expr,lists:concat(["#{",N,":=",Dst,"}"])},
+    {var,SrcVar} = Val,
+    {[{assign,DstExpr,SrcVar}],Dst0}.
+
 enc_cg(Imm0, false) ->
     Imm1 = enc_cse(Imm0),
     Imm2 = enc_pre_cg(Imm1),
@@ -1231,6 +1254,20 @@ enc_length(Len, {Lb,Ub}, Aligned) when is_integer(Lb) ->
 enc_length(Len, Sv, _Aligned) when is_integer(Sv) ->
     [{'cond',[[{eq,Len,Sv}]]}].
 
+extensions_bitmap(Vs, Undefined) ->
+    Highest = 1 bsl (length(Vs)-1),
+    Cs = extensions_bitmap_1(Vs, Undefined, Highest),
+    lists:flatten(lists:join(" bor ", Cs)).
+
+extensions_bitmap_1([{var,V}|Vs], Undefined, Power) ->
+    S = ["case ",V," of\n",
+         "  ",Undefined," -> 0;\n"
+         "  _ -> ",integer_to_list(Power),"\n"
+         "end"],
+    [S|extensions_bitmap_1(Vs, Undefined, Power bsr 1)];
+extensions_bitmap_1([], _, _) ->
+    [].
+
 put_bits_binary(Bin, _Unit, Aligned) when is_binary(Bin) ->
     Sz = byte_size(Bin),
     <<Int:Sz/unit:8>> = Bin,