support zstd as a decompressor

1 files changed, 9 insertions, 0 deletions

diff --git a/dedup/compression.py b/dedup/compression.py
index 2e9869c..742d7fd 100644
--- a/dedup/compression.py
+++ b/dedup/compression.py
@@ -5,6 +5,11 @@ import zlib
 
 import lzma
 
+try:
+    import zstandard
+except ImportError:
+    zstandard = None
+
 
 class Decompressor(typing.Protocol):
     def copy(self) -> "Decompressor":
@@ -196,6 +201,10 @@ decompressors = {
     '.xz':   lzma.LZMADecompressor,
 }
 
+if zstandard is not None:
+    decompressors[".zst"] = zstandard.ZstdDecompressor
+
+
 def decompress(filelike: typing.BinaryIO, extension: str) -> typing.BinaryIO:
     """Decompress a stream according to its extension.
     @param filelike: is a read-only byte-stream. It must support read(size) and