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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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28
Modules/binascii.c
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@ -898,33 +898,21 @@ static PyObject *
binascii_crc32(PyObject *self, PyObject *args)
{ /* By Jim Ahlstrom; All rights transferred to CNRI */
unsigned char *bin_data;
unsigned long crc = 0UL; /* initial value of CRC */
unsigned int crc = 0; /* initial value of CRC */
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;
crc = ~ crc;
#if SIZEOF_LONG > 4
/* only want the trailing 32 bits */
crc &= 0xFFFFFFFFUL;
#endif
while (len--)
crc = crc_32_tab[(crc ^ *bin_data++) & 0xffUL] ^ (crc >> 8);
while (len--) {
crc = crc_32_tab[(crc ^ *bin_data++) & 0xff] ^ (crc >> 8);
/* Note: (crc >> 8) MUST zero fill on left */
}
result = (long)(crc ^ 0xFFFFFFFFUL);
#if SIZEOF_LONG > 4
/* 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);
result = (crc ^ 0xFFFFFFFF);
return PyLong_FromUnsignedLong(result & 0xffffffff);
}