Issue #18585: speed zipfile import by only generating zipfile._ZipDecryptor on demand
diff --git a/Lib/zipfile.py b/Lib/zipfile.py
index fad52a2..173d990 100644
--- a/Lib/zipfile.py
+++ b/Lib/zipfile.py
@@ -475,13 +475,15 @@
crc = ((crc >> 1) & 0x7FFFFFFF)
table[i] = crc
return table
- crctable = _GenerateCRCTable()
+ crctable = None
def _crc32(self, ch, crc):
"""Compute the CRC32 primitive on one byte."""
return ((crc >> 8) & 0xffffff) ^ self.crctable[(crc ^ ch) & 0xff]
def __init__(self, pwd):
+ if _ZipDecrypter.crctable is None:
+ _ZipDecrypter.crctable = _ZipDecrypter._GenerateCRCTable()
self.key0 = 305419896
self.key1 = 591751049
self.key2 = 878082192