Issue #22341: Drop Python 2 workaround and document CRC initial value

Also align the parameter naming in binascii to be consistent with zlib.

4 files changed, 13 insertions, 24 deletions

diff --git a/Lib/gzip.py b/Lib/gzip.py
index 45152e4..3a2b322 100644
--- a/Lib/gzip.py
+++ b/Lib/gzip.py
@@ -210,7 +210,7 @@ class GzipFile(_compression.BaseStream):
 
     def _init_write(self, filename):
         self.name = filename
-        self.crc = zlib.crc32(b"") & 0xffffffff
+        self.crc = zlib.crc32(b"")
         self.size = 0
         self.writebuf = []
         self.bufsize = 0
@@ -261,7 +261,7 @@ class GzipFile(_compression.BaseStream):
         if length > 0:
             self.fileobj.write(self.compress.compress(data))
             self.size += length
-            self.crc = zlib.crc32(data, self.crc) & 0xffffffff
+            self.crc = zlib.crc32(data, self.crc)
             self.offset += length
 
         return length
@@ -381,7 +381,7 @@ class _GzipReader(_compression.DecompressReader):
         self._last_mtime = None
 
     def _init_read(self):
-        self._crc = zlib.crc32(b"") & 0xffffffff
+        self._crc = zlib.crc32(b"")
         self._stream_size = 0  # Decompressed size of unconcatenated stream
 
     def _read_exact(self, n):
@@ -485,7 +485,7 @@ class _GzipReader(_compression.DecompressReader):
         return uncompress
 
     def _add_read_data(self, data):
-        self._crc = zlib.crc32(data, self._crc) & 0xffffffff
+        self._crc = zlib.crc32(data, self._crc)
         self._stream_size = self._stream_size + len(data)
 
     def _read_eof(self):
diff --git a/Lib/tarfile.py b/Lib/tarfile.py
index ca45126..9d22c8e 100755
--- a/Lib/tarfile.py
+++ b/Lib/tarfile.py
@@ -459,13 +459,7 @@ class _Stream:
                 self.fileobj.write(self.buf)
                 self.buf = b""
                 if self.comptype == "gz":
-                    # The native zlib crc is an unsigned 32-bit integer, but
-                    # the Python wrapper implicitly casts that to a signed C
-                    # long.  So, on a 32-bit box self.crc may "look negative",
-                    # while the same crc on a 64-bit box may "look positive".
-                    # To avoid irksome warnings from the `struct` module, force
-                    # it to look positive on all boxes.
-                    self.fileobj.write(struct.pack("<L", self.crc & 0xffffffff))
+                    self.fileobj.write(struct.pack("<L", self.crc))
                     self.fileobj.write(struct.pack("<L", self.pos & 0xffffFFFF))
         finally:
             if not self._extfileobj:
diff --git a/Lib/test/test_zlib.py b/Lib/test/test_zlib.py
index 88c415b..ecdb5a7 100644
--- a/Lib/test/test_zlib.py
+++ b/Lib/test/test_zlib.py
@@ -47,16 +47,11 @@ class ChecksumTestCase(unittest.TestCase):
         self.assertEqual(zlib.adler32(b"", 1), 1)
         self.assertEqual(zlib.adler32(b"", 432), 432)
 
-    def assertEqual32(self, seen, expected):
-        # 32-bit values masked -- checksums on 32- vs 64- bit machines
-        # This is important if bit 31 (0x08000000L) is set.
-        self.assertEqual(seen & 0x0FFFFFFFF, expected & 0x0FFFFFFFF)
-
     def test_penguins(self):
-        self.assertEqual32(zlib.crc32(b"penguin", 0), 0x0e5c1a120)
-        self.assertEqual32(zlib.crc32(b"penguin", 1), 0x43b6aa94)
-        self.assertEqual32(zlib.adler32(b"penguin", 0), 0x0bcf02f6)
-        self.assertEqual32(zlib.adler32(b"penguin", 1), 0x0bd602f7)
+        self.assertEqual(zlib.crc32(b"penguin", 0), 0x0e5c1a120)
+        self.assertEqual(zlib.crc32(b"penguin", 1), 0x43b6aa94)
+        self.assertEqual(zlib.adler32(b"penguin", 0), 0x0bcf02f6)
+        self.assertEqual(zlib.adler32(b"penguin", 1), 0x0bd602f7)
 
         self.assertEqual(zlib.crc32(b"penguin"), zlib.crc32(b"penguin", 0))
         self.assertEqual(zlib.adler32(b"penguin"),zlib.adler32(b"penguin",1))
diff --git a/Lib/zipfile.py b/Lib/zipfile.py
index bee00d0..56a2479 100644
--- a/Lib/zipfile.py
+++ b/Lib/zipfile.py
@@ -734,7 +734,7 @@ class ZipExtFile(io.BufferedIOBase):
 
         if hasattr(zipinfo, 'CRC'):
             self._expected_crc = zipinfo.CRC
-            self._running_crc = crc32(b'') & 0xffffffff
+            self._running_crc = crc32(b'')
         else:
             self._expected_crc = None
 
@@ -856,7 +856,7 @@ class ZipExtFile(io.BufferedIOBase):
         if self._expected_crc is None:
             # No need to compute the CRC if we don't have a reference value
             return
-        self._running_crc = crc32(newdata, self._running_crc) & 0xffffffff
+        self._running_crc = crc32(newdata, self._running_crc)
         # Check the CRC if we're at the end of the file
         if self._eof and self._running_crc != self._expected_crc:
             raise BadZipFile("Bad CRC-32 for file %r" % self.name)
@@ -1492,7 +1492,7 @@ class ZipFile:
                     if not buf:
                         break
                     file_size = file_size + len(buf)
-                    CRC = crc32(buf, CRC) & 0xffffffff
+                    CRC = crc32(buf, CRC)
                     if cmpr:
                         buf = cmpr.compress(buf)
                         compress_size = compress_size + len(buf)
@@ -1567,7 +1567,7 @@ class ZipFile:
 
             self._writecheck(zinfo)
             self._didModify = True
-            zinfo.CRC = crc32(data) & 0xffffffff       # CRC-32 checksum
+            zinfo.CRC = crc32(data)       # CRC-32 checksum
             co = _get_compressor(zinfo.compress_type)
             if co:
                 data = co.compress(data) + co.flush()