Packages
kafka_protocol
4.1.5
4.3.4
4.3.3
4.3.2
4.3.1
4.3.0
4.2.9
4.2.8
4.2.7
4.2.6
4.2.5
4.2.4
4.2.3
4.2.2
4.2.1
4.2.0
4.1.10
4.1.9
4.1.8
4.1.7
4.1.6
4.1.5
4.1.4
4.1.3
4.1.2
4.1.1
4.1.0
4.0.3
4.0.2
4.0.1
3.0.1
3.0.0
2.4.1
2.3.6
2.3.5
2.3.4
2.3.3
2.3.2
2.3.1
2.3.0
2.2.9
2.2.8
2.2.7
2.2.6
2.2.5
2.2.4
2.2.3
2.2.2
2.2.1
2.2.0
2.1.2
2.1.1
2.1.0
2.0.1
2.0.0
1.1.3
1.1.2
1.1.1
1.1.0
1.0.0
0.9.2
0.9.1
0.9.0
0.8.0
0.7.8
0.7.7
0.7.6
0.7.5
0.7.4
0.7.3
0.7.2
0.7.1
0.7.0
0.6.0
0.4.0
0.3.2
0.3.1
0.2.3
Kafka protocol library for Erlang/Elixir
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src/kpro_varint.erl
%%% Copyright (c) 2018-2021, Klarna Bank AB (publ)
%%%
%%% Licensed under the Apache License, Version 2.0 (the "License");
%%% you may not use this file except in compliance with the License.
%%% You may obtain a copy of the License at
%%%
%%% http://www.apache.org/licenses/LICENSE-2.0
%%%
%%% Unless required by applicable law or agreed to in writing, software
%%% distributed under the License is distributed on an "AS IS" BASIS,
%%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
%%% See the License for the specific language governing permissions and
%%% limitations under the License.
-module(kpro_varint).
-compile({inline, [enc_zigzag/1]}).
-export([ encode/1
, decode/1
]).
-export([ encode_unsigned/1
, decode_unsigned/1
]).
-define(MAX_BITS, 63).
%% @doc Decode varint.
-spec decode(binary()) -> {integer(), binary()}.
decode(Bin) ->
dec_zigzag(dec_varint(Bin)).
%% @doc Encode varint.
-spec encode(kpro:int64()) -> iodata().
encode(Int) ->
enc_varint(enc_zigzag(Int)).
%% @doc Encode unsigned varint.
-spec encode_unsigned(non_neg_integer()) -> iodata().
encode_unsigned(Int) when Int >= 0 ->
enc_varint(Int).
%% @doc Decode unsigned varint.
-spec decode_unsigned(binary()) -> {non_neg_integer(), binary()}.
decode_unsigned(Bin) ->
dec_varint(Bin).
-spec enc_zigzag(integer()) -> non_neg_integer().
enc_zigzag(Int) ->
true = (Int >= -(1 bsl ?MAX_BITS)),
true = (Int < ((1 bsl ?MAX_BITS) - 1)),
(Int bsl 1) bxor (Int bsr ?MAX_BITS).
-spec enc_varint(non_neg_integer()) -> iodata().
enc_varint(I) when I =< 127 ->
[I];
enc_varint(I) ->
[128 + I band 127 | enc_varint(I bsr 7)].
-spec dec_zigzag({integer(), binary()} | integer()) ->
{integer(), binary()} | integer().
dec_zigzag({Int, TailBin}) ->
{(Int bsr 1) bxor -(Int band 1), TailBin}.
-spec dec_varint(binary()) -> {integer(), binary()}.
dec_varint(Bin) ->
dec_varint(Bin, 0, 0).
-spec dec_varint(binary(), integer(), integer()) -> {integer(), binary()}.
dec_varint(Bin, Acc, AccBits) ->
true = (AccBits =< ?MAX_BITS), %% assert
<<Tag:1, Value:7, Tail/binary>> = Bin,
NewAcc = (Value bsl AccBits) bor Acc,
case Tag =:= 0 of
true -> {NewAcc, Tail};
false -> dec_varint(Tail, NewAcc, AccBits + 7)
end.
%%%_* Emacs ====================================================================
%%% Local Variables:
%%% allout-layout: t
%%% erlang-indent-level: 2
%%% End: