diff options
Diffstat (limited to 'lib/asn1')
| -rw-r--r-- | lib/asn1/src/asn1ct_imm.erl | 118 |
1 files changed, 110 insertions, 8 deletions
diff --git a/lib/asn1/src/asn1ct_imm.erl b/lib/asn1/src/asn1ct_imm.erl index 1d1013b0a9..1b6a25b917 100644 --- a/lib/asn1/src/asn1ct_imm.erl +++ b/lib/asn1/src/asn1ct_imm.erl @@ -20,7 +20,8 @@ -module(asn1ct_imm). -export([per_dec_boolean/0,per_dec_enumerated/2,per_dec_enumerated/3, per_dec_integer/2,per_dec_length/3,per_dec_named_integer/3, - per_dec_octet_string/2, + per_dec_octet_string/2]). +-export([optimize_alignment/1,optimize_alignment/2, dec_slim_cg/2,dec_code_gen/2]). -export([effective_constraint/2]). -import(asn1ct_gen, [emit/1]). @@ -28,7 +29,8 @@ -record(st, {var, base}). -dec_slim_cg(Imm, BytesVar) -> +dec_slim_cg(Imm0, BytesVar) -> + {Imm,_} = optimize_alignment(Imm0), asn1ct_name:new(v), [H|T] = atom_to_list(asn1ct_name:curr(v)) ++ "@", VarBase = [H-($a-$A)|T], @@ -45,6 +47,13 @@ dec_code_gen(Imm, BytesVar) -> "end"]), ok. +optimize_alignment(Imm) -> + opt_al(Imm, unknown). + +optimize_alignment(Imm, Al) -> + opt_al(Imm, Al). + + per_dec_boolean() -> {map,{get_bits,1,[1]},[{0,false},{1,true}]}. @@ -211,6 +220,91 @@ per_num_bits(N) when N =< 128 -> 7; per_num_bits(N) when N =< 255 -> 8. %%% +%%% Remove unnecessary aligning to octet boundaries. +%%% + +opt_al({get_bits,E0,Opts0}, A0) -> + {E,A1} = opt_al(E0, A0), + Opts = opt_al_1(A1, Opts0), + A = update_al(A1, E, Opts), + {{get_bits,E,Opts},A}; +opt_al({call,Fun,E0}, A0) -> + {E,A} = opt_al(E0, A0), + {{call,Fun,E},A}; +opt_al({convert,Op,E0}, A0) -> + {E,A} = opt_al(E0, A0), + {{convert,Op,E},A}; +opt_al({value,E0}, A0) -> + {E,A} = opt_al(E0, A0), + {{value,E},A}; +opt_al({add,E0,I}, A0) when is_integer(I) -> + {E,A} = opt_al(E0, A0), + {{add,E,I},A}; +opt_al({test,E0,V,B0}, A0) -> + {E,A1} = opt_al(E0, A0), + {B,A2} = opt_al(B0, A1), + {{test,E,V,B},A2}; +opt_al({'case',Cs0}, A0) -> + {Cs,A} = opt_al_cs(Cs0, A0), + {{'case',Cs},A}; +opt_al({map,E0,Cs}, A0) -> + {E,A} = opt_al(E0, A0), + {{map,E,Cs},A}; +opt_al(I, A) when is_integer(I) -> + {I,A}. + +opt_al_cs([C0|Cs0], A0) -> + {C,A1} = opt_al(C0, A0), + {Cs,A2} = opt_al_cs(Cs0, A0), + {[C|Cs],merge_al(A1, A2)}; +opt_al_cs([], _) -> {[],none}. + +merge_al(unknown, _) -> unknown; +merge_al(Other, none) -> Other; +merge_al(_, unknown) -> unknown; +merge_al(I0, I1) -> + case {I0 rem 8,I1 rem 8} of + {I,I} -> I; + {_,_} -> unknown + end. + +opt_al_1(unknown, Opts) -> + Opts; +opt_al_1(A, Opts0) -> + case alignment(Opts0) of + none -> + Opts0; + full -> + case A rem 8 of + 0 -> + %% Already in alignment. + proplists:delete(align, Opts0); + Bits -> + %% Cheaper alignment with a constant padding. + Opts1 = proplists:delete(align, Opts0), + [{align,8-Bits }|Opts1] + end; + A -> %Assertion. + Opts0 + end. + +update_al(A0, E, Opts) -> + A = case alignment(Opts) of + none -> A0; + full -> 0; + Bits when is_integer(A0) -> + 0 = (A0 + Bits) rem 8; %Assertion. + _ -> + 0 + end, + [U] = [U || U <- Opts, is_integer(U)], + if + U rem 8 =:= 0 -> A; + is_integer(A), is_integer(E) -> A + U*E; + true -> unknown + end. + +%%% %%% Flatten the intermediate format and assign temporaries. %%% @@ -288,16 +382,21 @@ flatten_hoist_align_1([], Ab, Acc) -> {[Ab],lists:reverse(Acc)}. flatten_align({get_bits,{SrcBits,SrcBuf},U,Dst}=Gb0, Pre, St0) -> - case is_aligned(U) of - false -> + case alignment(U) of + none -> flatten_align_1(U, Dst, Pre++[Gb0], St0); - true -> + full -> {PadBits,St1} = new_var("Pad", St0), {DstBuf,St2} = new_var("Buf", St1), Ab = {align_bits,SrcBuf,PadBits}, Agb = {get_bits,{PadBits,SrcBuf},[1],{'_',DstBuf}}, Gb = {get_bits,{SrcBits,DstBuf},U,Dst}, - flatten_align_1(U, Dst, Pre++[Ab,Agb,Gb], St2) + flatten_align_1(U, Dst, Pre++[Ab,Agb,Gb], St2); + PadBits when is_integer(PadBits), PadBits > 0 -> + {DstBuf,St1} = new_var("Buf", St0), + Agb = {get_bits,{PadBits,SrcBuf},[1],{'_',DstBuf}}, + Gb = {get_bits,{SrcBits,DstBuf},U,Dst}, + flatten_align_1(U, Dst, Pre++[Agb,Gb], St1) end. flatten_align_1(U, {D,_}=Dst, Pre, St) -> @@ -316,8 +415,11 @@ new_var_pair(St0) -> new_var(Tag, #st{base=VarBase,var=N}=St) -> {VarBase++Tag++integer_to_list(N),St#st{var=N+1}}. -is_aligned(Fl) -> - proplists:get_bool(align, Fl). +alignment([{align,false}|_]) -> none; +alignment([{align,true}|_]) -> full; +alignment([{align,Bits}|_]) -> Bits; +alignment([_|T]) -> alignment(T); +alignment([]) -> none. is_non_zero(Fl) -> lists:member(non_zero, Fl). |