zstd-erlang
=====
[](https://hex.pm/packages/zstd)
Zstd binding for Erlang/Elixir
http://facebook.github.io/zstd/
The current version uses [v1.5.4](https://github.com/facebook/zstd/releases/tag/v1.5.4)
Usage
-----
```
zstd:compress(Binary).
zstd:compress(Binary, CompressionLevel).
zstd:decompress(Binary).
```
```
1> Compressed = zstd:compress(<<"Hello, World!">>).
<<40,181,47,253,32,13,105,0,0,72,101,108,108,111,44,32,87,
111,114,108,100,33>>
2> zstd:decompress(Compressed).
<<"Hello, World!">>
```
```
compress_file() ->
{ok, File} = file:open("test.txt.zst", [write, raw, delayed_write, sync]),
Bin = << <<"A">> || _ <- lists:seq(1, 1024 * 1024) >>,
CStream = zstd:new_compression_stream(),
ok = zstd:compression_stream_init(CStream),
{ok, ResC} = zstd:stream_compress(CStream, Bin),
file:write(File, ResC),
{ok, ResF} = zstd:stream_flush(CStream),
file:write(File, ResF),
file:close(File).
decompress_file() ->
{ok, Data} = file:read_file("test.txt.zst"),
DStream = zstd:new_decompression_stream(),
ok = zstd:decompression_stream_init(DStream),
{ok, Bin} = zstd:stream_decompress(DStream, Data),
io:format("~s", [Bin]),
io:format("Size: ~p~n", [size(Bin)]).
decompress_large_file() ->
DStream = zstd:new_decompression_stream(),
ok = zstd:decompression_stream_init(DStream),
{ok, RFile} = file:open("somefile.log.ztd", [read, raw, binary, read_ahead]),
{ok, WFile} = file:open("somefile.log", [write, raw, delayed_write, sync]),
read_file(RFile, WFile, DStream),
file:close(RFile),
file:close(WFile).
read_file(RFile, WFile, DStream) ->
case file:read(RFile, 1024 * 8) of
{ok, Data} ->
{ok, Bin} = zstd:stream_decompress(DStream, Data),
file:write(WFile, Bin),
read_file(RFile, WFile, DStream);
eof ->
ok
end.
```
#### For Elixir
```
iex(1)> compressed = :zstd.compress("Hello, World!")
<<40, 181, 47, 253, 32, 13, 105, 0, 0, 72, 101, 108, 108, 111, 44, 32, 87, 111,
114, 108, 100, 33>>
iex(2)> :zstd.decompress(compressed)
"Hello, World!"
```
