[Swig-devel] [ swig-Bugs-3429388 ] not handling 0xffffffff correctly as UINT32 input to C func

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Bugs item #3429388, was opened at 2011-10-27 10:54
Message generated for change (Comment added) made by weihongbin
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Category: python
Group: None
Status: Open
Resolution: None
Priority: 5
Private: No
Submitted By: Hongbin Wei (weihongbin)
Assigned to: Nobody/Anonymous (nobody)
Summary: not handling 0xffffffff correctly as UINT32 input to C func

Initial Comment:
I have a C function “void Uint32_Test(UINT32 num)”. when I pass in a 0xffffffff as the argument from Python to the wrapper function, I get “overflowerror : in method ‘Uint32_Test’, argument 1 of type ‘UINT32’”. 

Looking into the wrappers, I found that the error is generated at the lines of following method marked by "<==". Obviously 0xffffffff is being treated as a singed value although it's expected to be an unsigned. 

SWIGINTERN int
SWIG_AsVal_unsigned_SS_long (PyObject *obj, unsigned long *val) 
{
  if (PyInt_Check(obj)) {
    long v = PyInt_AsLong(obj);      <==
    if (v >= 0) {                                <==
      if (val) *val = v;
      return SWIG_OK;
    } else {
      return SWIG_OverflowError;
    }
  } else if (PyLong_Check(obj)) {
    unsigned long v = PyLong_AsUnsignedLong(obj);
    if (!PyErr_Occurred()) {
      if (val) *val = v;
      return SWIG_OK;
    } else {
      PyErr_Clear();
    }
  }
#ifdef SWIG_PYTHON_CAST_MODE
  {
    int dispatch = 0;
    unsigned long v = PyLong_AsUnsignedLong(obj);
    if (!PyErr_Occurred()) {
      if (val) *val = v;
      return SWIG_AddCast(SWIG_OK);
    } else {
      PyErr_Clear();
    }
    if (!dispatch) {
      double d;
      int res = SWIG_AddCast(SWIG_AsVal_double (obj,&d));
      if (SWIG_IsOK(res) && SWIG_CanCastAsInteger(&d, 0, ULONG_MAX)) {
       if (val) *val = (unsigned long)(d);
       return res;
      }
    }
  }
#endif
  return SWIG_TypeError;
}


----------------------------------------------------------------------

>Comment By: Hongbin Wei (weihongbin)
Date: 2011-11-04 17:01

Message:
Thanks, Stefan. Your latest patch works.

----------------------------------------------------------------------

Comment By: szager (szager)
Date: 2011-11-01 11:52

Message:
OK, I have updated the patch.  Note that the new patch has diffs for two
files, not one.

Please try applying the patches to the SWIG source files, and *not* to
your generated wrappers.  A fix which can't be applied to source files is
useless.  Although it is confusing to see a change only in SWIG_AsVal_dec,
that is in fact the correct place to fix this.

Thanks,

Stefan

----------------------------------------------------------------------

Comment By: Hongbin Wei (weihongbin)
Date: 2011-10-31 16:12

Message:
I looked at the patch.
1) On my system, it's SWIGINTERN int SWIG_AsVal_unsigned_SS_long (PyObject
*obj, unsigned long *val) that got generated, called and triggered the
failure, not  SWIG_AsVal_dec(unsigned long)(PyObject *obj, unsigned long
*val). 
2) I merged the patch to SWIGINTERN int SWIG_AsVal_unsigned_SS_long
(PyObject *obj, unsigned long *val), and replacing
PyInt_AsUnsignedLongMask(obj) with PyLong_AsUnsignedLongMask(obj) since the
PyInt_AsUnsignedLongMask(obj) is not defined. And found out that
PyErr_Occurred() returns TRUE, thus the same error message as before.
3) I tried replacing "if (v >= 0) {" with "if (!PyErr_Occurred()) {" only.
That seems working fine.




----------------------------------------------------------------------

Comment By: szager (szager)
Date: 2011-10-28 21:13

Message:
I can't reproduce this with 64-bit python, and I don't have a 32-bit python
installation to try it with.  Can you please try applying the patch
attached to this bug, and let me know if it fixes the problem?

----------------------------------------------------------------------

Comment By: Hongbin Wei (weihongbin)
Date: 2011-10-27 14:19

Message:
Thanks Stefan. Here's the output of the commands.
>>> platform.architecture()
('32bit', 'WinddowsPE')
>>> platform.python_version()
'3.2.0'

----------------------------------------------------------------------

Comment By: szager (szager)
Date: 2011-10-27 11:52

Message:
I have a proposed fix for this, but I'm unable to reproduce the problem. 
Can you please provide some details about the system you're running on:

- Please send the output of this command:

python -c 'import platform; print platform.architecture(); print
platform.python_version()'

- If you're on a linux system, please send the output of this command:

uname -a

Thanks,

Stefan

----------------------------------------------------------------------

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