%%
%% %CopyrightBegin%
%%
%% Copyright Ericsson AB 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(asn1rtt_per_common).
-include("asn1_records.hrl").
-export([decode_fragmented/3,
decode_compact_bit_string/1,
decode_legacy_bit_string/1,
decode_named_bit_string/2,
decode_chars/2,decode_chars/3,
decode_chars_16bit/1,
decode_big_chars/2]).
-define('16K',16384).
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).
decode_named_bit_string(Val, NNL) ->
Bits = [B || <<B:1>> <= Val],
decode_named_bit_string_1(0, Bits, NNL, []).
decode_legacy_bit_string(Val) ->
[B || <<B:1>> <= Val].
decode_compact_bit_string(Val) ->
PadLen = (8 - (bit_size(Val) band 7)) band 7,
{PadLen,<<Val/bitstring,0:PadLen>>}.
decode_chars(Val, N) ->
[C || <<C:N>> <= Val].
decode_chars(Val, N, Chars) ->
[element(C+1, Chars) || <<C:N>> <= Val].
decode_chars_16bit(Val) ->
Cs = [C || <<C:16>> <= Val],
decode_chars_16bit_1(Cs).
decode_big_chars(Val, N) ->
decode_big_chars_1(decode_chars(Val, N)).
%%%
%%% Internal functions.
%%%
decode_named_bit_string_1(Pos, [0|Bt], Names, Acc) ->
decode_named_bit_string_1(Pos+1, Bt, Names, Acc);
decode_named_bit_string_1(Pos, [1|Bt], Names, Acc) ->
case lists:keyfind(Pos, 2, Names) of
{Name,_} ->
decode_named_bit_string_1(Pos+1, Bt, Names, [Name|Acc]);
false ->
decode_named_bit_string_1(Pos+1, Bt, Names, [{bit,Pos}|Acc])
end;
decode_named_bit_string_1(_Pos, [], _Names, Acc) ->
lists:reverse(Acc).
decode_chars_16bit_1([H|T]) when H < 256 ->
[H|decode_chars_16bit_1(T)];
decode_chars_16bit_1([H|T]) ->
[{0,0,H bsr 8,H band 255}|decode_chars_16bit_1(T)];
decode_chars_16bit_1([]) -> [].
decode_big_chars_1([H|T]) when H < 256 ->
[H|decode_big_chars_1(T)];
decode_big_chars_1([H|T]) ->
[list_to_tuple(binary_to_list(<<H:32>>))|decode_big_chars_1(T)];
decode_big_chars_1([]) -> [].
