feat: Add gzip decompression to Parquet.

Author: mchav

dataframe.cabal

@@ -107,6 +107,7 @@ library
                       unordered-containers >= 0.1 && < 1,
                       vector ^>= 0.13,
                       vector-algorithms ^>= 0.9,
+                      zlib >= 0.5 && < 1,
                       zstd >= 0.1.2.0 && < 0.2,
                       mmap >= 0.5.8 && <= 0.5.9,
                       parallel >= 3.2.2.0 && < 5
@@ -124,6 +125,7 @@ executable dataframe-benchmark-example
                       dataframe ^>= 0.3,
                       random >= 1 && < 2,
                       time >= 1.12 && < 2,
+                      text,
                       vector ^>= 0.13,
     hs-source-dirs:   app
     default-language: Haskell2010

src/DataFrame/IO/Parquet/Page.hs

@@ -3,9 +3,11 @@
 
 module DataFrame.IO.Parquet.Page where
 
+import qualified Codec.Compression.GZip as GZip
 import Codec.Compression.Zstd.Streaming
 import Data.Bits
 import qualified Data.ByteString as BSO
+import qualified Data.ByteString.Lazy as LB
 import Data.Int
 import Data.Maybe (fromMaybe, listToMaybe)
 import Data.Word
@@ -42,6 +44,7 @@ readPage c columnBytes = do
             Left e -> error (show e)
             Right res -> pure res
         UNCOMPRESSED -> pure (BSO.pack compressed)
+        GZIP -> pure (LB.toStrict (GZip.decompress (LB.pack compressed)))
         other -> error ("Unsupported compression type: " ++ show other)
     pure
         ( Just $ Page hdr (BSO.unpack fullData)