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crc32 always returns unsigned. cleanup the code a bit and revert r61648 with

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the proper fix.
This commit is contained in:
Gregory P. Smith 2008-03-20 06:20:09 +00:00
parent 97797a9c3c
commit 2727503bc9
3 changed files with 16 additions and 28 deletions
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4
Lib/test/test_zlib.py
View file

@ -42,14 +42,14 @@ class ChecksumTestCase(unittest.TestCase):
def test_crc32_adler32_unsigned(self): def test_crc32_adler32_unsigned(self):
foo = 'abcdefghijklmnop' foo = 'abcdefghijklmnop'
# explicitly test signed behavior # explicitly test signed behavior
self.assertEqual(zlib.crc32(foo), -1808088941) self.assertEqual(zlib.crc32(foo), 2486878355)
self.assertEqual(zlib.crc32('spam'), 1138425661) self.assertEqual(zlib.crc32('spam'), 1138425661)
self.assertEqual(zlib.adler32(foo+foo), 3573550353) self.assertEqual(zlib.adler32(foo+foo), 3573550353)
self.assertEqual(zlib.adler32('spam'), 72286642) self.assertEqual(zlib.adler32('spam'), 72286642)
def test_same_as_binascii_crc32(self): def test_same_as_binascii_crc32(self):
foo = 'abcdefghijklmnop' foo = 'abcdefghijklmnop'
crc = -1808088941 crc = 2486878355
self.assertEqual(binascii.crc32(foo), crc) self.assertEqual(binascii.crc32(foo), crc)
self.assertEqual(zlib.crc32(foo), crc) self.assertEqual(zlib.crc32(foo), crc)
self.assertEqual(binascii.crc32('spam'), zlib.crc32('spam')) self.assertEqual(binascii.crc32('spam'), zlib.crc32('spam'))

28
Modules/binascii.c
View file

@ -898,33 +898,21 @@ static PyObject *
binascii_crc32(PyObject *self, PyObject *args) binascii_crc32(PyObject *self, PyObject *args)
{ /* By Jim Ahlstrom; All rights transferred to CNRI */ { /* By Jim Ahlstrom; All rights transferred to CNRI */
unsigned char *bin_data; unsigned char *bin_data;
unsigned long crc = 0UL; /* initial value of CRC */ unsigned int crc = 0; /* initial value of CRC */
Py_ssize_t len; Py_ssize_t len;
long result; unsigned int result;
if ( !PyArg_ParseTuple(args, "s#|k:crc32", &bin_data, &len, &crc) ) if ( !PyArg_ParseTuple(args, "s#|I:crc32", &bin_data, &len, &crc) )
return NULL; return NULL;
crc = ~ crc; crc = ~ crc;
#if SIZEOF_LONG > 4 while (len--) {
/* only want the trailing 32 bits */ crc = crc_32_tab[(crc ^ *bin_data++) & 0xff] ^ (crc >> 8);
crc &= 0xFFFFFFFFUL;
#endif
while (len--)
crc = crc_32_tab[(crc ^ *bin_data++) & 0xffUL] ^ (crc >> 8);
/* Note: (crc >> 8) MUST zero fill on left */ /* Note: (crc >> 8) MUST zero fill on left */
}
result = (long)(crc ^ 0xFFFFFFFFUL); result = (crc ^ 0xFFFFFFFF);
#if SIZEOF_LONG > 4 return PyLong_FromUnsignedLong(result & 0xffffffff);
/* Extend the sign bit. This is one way to ensure the result is the
* same across platforms. The other way would be to return an
* unbounded unsigned long, but the evidence suggests that lots of
* code outside this treats the result as if it were a signed 4-byte
* integer.
*/
result |= -(result & (1L << 31));
#endif
return PyLong_FromLong(result);
} }

12
Modules/zlibmodule.c
View file

@ -915,14 +915,14 @@ PyDoc_STRVAR(adler32__doc__,
static PyObject * static PyObject *
PyZlib_adler32(PyObject *self, PyObject *args) PyZlib_adler32(PyObject *self, PyObject *args)
{ {
uLong adler32val = adler32(0L, Z_NULL, 0); unsigned int adler32val = adler32(0L, Z_NULL, 0);
Byte *buf; Byte *buf;
int len; int len;
if (!PyArg_ParseTuple(args, "s#|k:adler32", &buf, &len, &adler32val)) if (!PyArg_ParseTuple(args, "s#|I:adler32", &buf, &len, &adler32val))
return NULL; return NULL;
adler32val = adler32(adler32val, buf, len); adler32val = adler32(adler32val, buf, len);
return PyLong_FromUnsignedLong(adler32val & 0xffffffff); return PyLong_FromUnsignedLong(adler32val & 0xffffffffU);
} }
PyDoc_STRVAR(crc32__doc__, PyDoc_STRVAR(crc32__doc__,
@ -934,13 +934,13 @@ PyDoc_STRVAR(crc32__doc__,
static PyObject * static PyObject *
PyZlib_crc32(PyObject *self, PyObject *args) PyZlib_crc32(PyObject *self, PyObject *args)
{ {
uLong crc32val = crc32(0L, Z_NULL, 0); unsigned int crc32val = crc32(0L, Z_NULL, 0);
Byte *buf; Byte *buf;
int len; int len;
if (!PyArg_ParseTuple(args, "s#|k:crc32", &buf, &len, &crc32val)) if (!PyArg_ParseTuple(args, "s#|I:crc32", &buf, &len, &crc32val))
return NULL; return NULL;
crc32val = crc32(crc32val, buf, len); crc32val = crc32(crc32val, buf, len);
return PyLong_FromLong(crc32val & 0xffffffff); return PyLong_FromUnsignedLong(crc32val & 0xffffffffU);
} }