Packages
kafka_protocol
2.1.2
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_compress.erl
%%% Copyright (c) 2018, Klarna AB
%%%
%%% 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_compress).
-export([ compress/2
, decompress/2
, codec_to_method/1
, method_to_codec/1
]).
-include("kpro_private.hrl").
%% @doc Translate codec in kafka batch attributes to compression method.
-spec codec_to_method(byte()) -> kpro:compress_option().
codec_to_method(A) when ?KPRO_IS_GZIP_ATTR(A) -> ?gzip;
codec_to_method(A) when ?KPRO_IS_SNAPPY_ATTR(A) -> ?snappy;
codec_to_method(A) when ?KPRO_IS_LZ4_ATTR(A) -> ?lz4;
codec_to_method(_) -> ?no_compression.
%% @doc Translate compression method to bits for kafka batch attributes.
method_to_codec(?gzip) -> ?KPRO_COMPRESS_GZIP;
method_to_codec(?snappy) -> ?KPRO_COMPRESS_SNAPPY;
method_to_codec(?lz4) -> ?KPRO_COMPRESS_LZ4;
method_to_codec(?no_compression) -> ?KPRO_COMPRESS_NONE.
%% @doc Compress encoded batch.
-spec compress(kpro:compress_option(), iodata()) -> iodata().
compress(?no_compression, IoData) -> IoData;
compress(?gzip, IoData) -> zlib:gzip(IoData);
compress(?snappy, IoData) -> snappy_compress(IoData).
%% @doc Decompress batch.
-spec decompress(kpro:compress_option(), binary()) -> binary().
decompress(?no_compression, Bin) -> Bin;
decompress(?gzip, Bin) -> zlib:gunzip(Bin);
decompress(?snappy, Bin) -> java_snappy_unpack(Bin).
%%%_* Internals ================================================================
%% Java snappy implementation has its own non-standard
%% magic header, see org/xerial/snappy/SnappyCodec.java
java_snappy_unpack(<<130, "SNAPPY", 0,
_Version:32, _MinCompatibleV:32, Chunks/binary>>) ->
java_snappy_unpack_chunks(Chunks, []);
java_snappy_unpack(Bin) ->
snappy_decompress(Bin).
java_snappy_unpack_chunks(<<>>, Acc) ->
iolist_to_binary(Acc);
java_snappy_unpack_chunks(Chunks, Acc) ->
<<Len:32/unsigned-integer, Rest/binary>> = Chunks,
case Len =:= 0 of
true ->
Rest =:= <<>> orelse erlang:error({Len, Rest}), %% assert
Acc;
false ->
<<Data:Len/binary, Tail/binary>> = Rest,
Decompressed = snappy_decompress(Data),
java_snappy_unpack_chunks(Tail, [Acc, Decompressed])
end.
snappy_decompress(BinData) ->
{ok, Decompressed} = snappyer:decompress(BinData),
Decompressed.
snappy_compress(IoData) ->
{ok, Compressed} = snappyer:compress(IoData),
Compressed.
%%%_* Emacs ====================================================================
%%% Local Variables:
%%% allout-layout: t
%%% erlang-indent-level: 2
%%% End: