Also align the parameter naming in binascii to be consistent with zlib.
possibly the last fragment).
-.. function:: crc_hqx(data, crc)
+.. function:: crc_hqx(data, value)
- Compute the binhex4 crc value of *data*, starting with an initial *crc* and
- returning the result.
+ Compute the binhex4 crc value of *data*, starting with *value* as the
+ initial crc, and return the result.
-.. function:: crc32(data[, crc])
+.. function:: crc32(data[, value])
- Compute CRC-32, the 32-bit checksum of data, starting with an initial crc. This
+ Compute CRC-32, the 32-bit checksum of *data*, starting with an
+ initial CRC of *value*. The default initial CRC is zero. The algorithm
is consistent with the ZIP file checksum. Since the algorithm is designed for
use as a checksum algorithm, it is not suitable for use as a general hash
algorithm. Use as follows::
print(binascii.crc32(b"hello world"))
# Or, in two pieces:
crc = binascii.crc32(b"hello")
- crc = binascii.crc32(b" world", crc) & 0xffffffff
+ crc = binascii.crc32(b" world", crc)
print('crc32 = {:#010x}'.format(crc))
-.. note::
- To generate the same numeric value across all Python versions and
- platforms use crc32(data) & 0xffffffff. If you are only using
- the checksum in packed binary format this is not necessary as the
- return value is the correct 32bit binary representation
- regardless of sign.
+ .. versionchanged:: 3.0
+ The result is always unsigned.
+ To generate the same numeric value across all Python versions and
+ platforms, use ``crc32(data) & 0xffffffff``.
.. function:: b2a_hex(data)
.. function:: adler32(data[, value])
Computes an Adler-32 checksum of *data*. (An Adler-32 checksum is almost as
- reliable as a CRC32 but can be computed much more quickly.) If *value* is
- present, it is used as the starting value of the checksum; otherwise, a fixed
- default value is used. This allows computing a running checksum over the
+ reliable as a CRC32 but can be computed much more quickly.) The result
+ is an unsigned 32-bit integer. If *value* is present, it is used as
+ the starting value of the checksum; otherwise, a default value of 1
+ is used. Passing in *value* allows computing a running checksum over the
concatenation of several inputs. The algorithm is not cryptographically
strong, and should not be used for authentication or digital signatures. Since
the algorithm is designed for use as a checksum algorithm, it is not suitable
for use as a general hash algorithm.
- Always returns an unsigned 32-bit integer.
-
-.. note::
- To generate the same numeric value across all Python versions and
- platforms use adler32(data) & 0xffffffff. If you are only using
- the checksum in packed binary format this is not necessary as the
- return value is the correct 32bit binary representation
- regardless of sign.
+ .. versionchanged:: 3.0
+ Always returns an unsigned value.
+ To generate the same numeric value across all Python versions and
+ platforms, use ``adler32(data) & 0xffffffff``.
.. function:: compress(data[, level])
single: Cyclic Redundancy Check
single: checksum; Cyclic Redundancy Check
- Computes a CRC (Cyclic Redundancy Check) checksum of *data*. If *value* is
- present, it is used as the starting value of the checksum; otherwise, a fixed
- default value is used. This allows computing a running checksum over the
+ Computes a CRC (Cyclic Redundancy Check) checksum of *data*. The
+ result is an unsigned 32-bit integer. If *value* is present, it is used
+ as the starting value of the checksum; otherwise, a default value of 0
+ is used. Passing in *value* allows computing a running checksum over the
concatenation of several inputs. The algorithm is not cryptographically
strong, and should not be used for authentication or digital signatures. Since
the algorithm is designed for use as a checksum algorithm, it is not suitable
for use as a general hash algorithm.
- Always returns an unsigned 32-bit integer.
-
- .. note::
-
+ .. versionchanged:: 3.0
+ Always returns an unsigned value.
To generate the same numeric value across all Python versions and
- platforms, use ``crc32(data) & 0xffffffff``. If you are only using
- the checksum in packed binary format this is not necessary as the
- return value is the correct 32-bit binary representation
- regardless of sign.
+ platforms, use ``crc32(data) & 0xffffffff``.
.. function:: decompress(data[, wbits[, bufsize]])
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
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
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):
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):
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:
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))
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
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)
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)
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()
projects / python / commitdiff