Merge pull request #227 from jeandet/lib_deflate

Adds automatic support for libdeflate which yields at least a 2x speedup
MAVENSDC · Jul 28, 2023 · dad8076 · dad8076
2 parents b44282a + 282056a
commit dad8076
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Showing 3 changed files with 14 additions and 7 deletions.
diff --git a/cdflib/cdfread.py b/cdflib/cdfread.py
@@ -1,4 +1,4 @@
-import gzip
+from .gzip_wrapper import gzip_inflate
 import hashlib
 import io
 import os
@@ -579,7 +579,7 @@ def _uncompress_file(self) -> None:
 
         if cType == 5:
             self._f.seek(data_start)
-            decompressed_data = gzip.decompress(self._f.read(data_size))
+            decompressed_data = gzip_inflate(self._f.read(data_size))
         elif cType == 1:
             self._f.seek(data_start)
             decompressed_data = self._uncompress_rle(self._f.read(data_size))
@@ -1982,7 +1982,7 @@ def _read_vvr_block(self, offset: int) -> bytes:
         if section_type == 13:
             # a CVVR
             compressed_size = int.from_bytes(block[8:16], "big")
-            return gzip.decompress(block[16 : 16 + compressed_size])
+            return gzip_inflate(block[16 : 16 + compressed_size])
         elif section_type == 7:
             # a VVR
             return block[4:]
@@ -2001,7 +2001,7 @@ def _read_vvr_block2(self, offset: int) -> bytes:
         if section_type == 13:
             # a CVVR
             compressed_size = int.from_bytes(block[8:12], "big")
-            return gzip.decompress(block[12 : 12 + compressed_size])
+            return gzip_inflate(block[12 : 12 + compressed_size])
         elif section_type == 7:
             # a VVR
             return block[4:]

diff --git a/cdflib/cdfwrite.py b/cdflib/cdfwrite.py
@@ -1,5 +1,5 @@
 import binascii
-import gzip
+from .gzip_wrapper import  gzip_deflate
 import hashlib
 import io
 import logging
@@ -1031,7 +1031,7 @@ def _write_var_data_nonsparse(
                     endrec = recs - 1
                     endloc = len(data)
                 bdata = data[startloc:endloc]
-                cdata = gzip.compress(bdata, compression)
+                cdata = gzip_deflate(bdata, compression)
                 if len(cdata) < len(bdata):
                     n1offset = self._write_cvvr(f, cdata)
                 else:
@@ -2065,7 +2065,7 @@ def _write_ccr(self, f: io.BufferedWriter, g: io.BufferedWriter, level: int) ->
         uSize = len(data)
         section_type = self.CCR_
         rfuA = 0
-        cData = gzip.compress(data, level)
+        cData = gzip_deflate(data, level)
         block_size = self.CCR_BASE_SIZE64 + len(cData)
         cprOffset = 0
         ccr1 = bytearray(32)

diff --git a/cdflib/gzip_wrapper.py b/cdflib/gzip_wrapper.py
@@ -0,0 +1,7 @@
+try:
+    from deflate import gzip_decompress as gzip_inflate
+    from deflate import gzip_compress as gzip_deflate
+
+except ImportError:
+    from gzip import decompress as gzip_inflate
+    from gzip import compress as gzip_deflate