[Patches] simple 64-bit fixes in Objects/ dir

Trent Mick trentm@activestate.com
Mon, 5 Jun 2000 15:39:34 -0700


Discussion:

This patch is one of a set of five (one per python/dist/src/* directory).
They have been broken up to keep the patches small such that people might
spend the time to review them. If one single patch would be prefered I can
provide that.

This patch makes some simple changes for the benefit of 64-bit platforms (to
avoid possible overflows where C data types have changed sizes and to
eliminate unnecessary warnings). Each change fits into one of the following
categories:

- Change a local variable declaration from int to size_t where appropriate.
  This is typically done for variables that hold strlen() or sizeof()
  results. On 64-bit platforms sizeof(int) < sizeof(size_t), so using size_t
  avoids a downcast warning (or overflow). The variable is often later
  downcast to an int anyway but it is (IMO) more appropriate to do the
  downcast where the downcast is necessary and not before. 32-bit platforms
  are not affected by this change.
- Change (int) casts to (size_t) casts within comparisons where appropriate.
  This can avoid an unnecessary possible overflow (in somecases) and a
  warning on 64-bit platforms.
- Remove pointer downcasts to (long) for comparison (see Objects/object.c).
  This is unreliable on Win64 where sizeof(void*) > sizeof(long).
- Add a check for int overflow and raise and OverflowError where it cannot be
  proven a priori that int will not overflow. This is usually associated with
  string lengths. While it may seem overkill to have a check to ensure that a
  string does not overflow 2G characters it *is* a potential for silent
  overflow.
- [Python/thread_nt.c] Use %p instead of %ld printf formatter for debugging
  output to print a pointer. %ld results in data loss on Win64.


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Patch:

*** /home/trentm/main/contrib/python/dist/src/Objects/classobject.c	Fri Jun  2 11:21:14 2000
--- /home/trentm/main/Apps/Perlium/Python/dist/src/Objects/classobject.c	Fri Jun  2 15:53:43 2000
***************
*** 283,289 ****
  {
  	if (v == NULL || !PyString_Check(v))
  		return "__name__ must be a string object";
! 	if ((long)strlen(PyString_AS_STRING(v)) != PyString_GET_SIZE(v))
  		return "__name__ must not contain null bytes";
  	set_slot(&c->cl_name, v);
  	return "";
--- 283,289 ----
  {
  	if (v == NULL || !PyString_Check(v))
  		return "__name__ must be a string object";
! 	if (strlen(PyString_AS_STRING(v)) != (size_t)PyString_GET_SIZE(v))
  		return "__name__ must not contain null bytes";
  	set_slot(&c->cl_name, v);
  	return "";
*** /home/trentm/main/contrib/python/dist/src/Objects/object.c	Fri Jun  2 11:21:14 2000
--- /home/trentm/main/Apps/Perlium/Python/dist/src/Objects/object.c	Fri Jun  2 15:53:43 2000
***************
*** 367,373 ****
  	if (pair == NULL) {
  		return NULL;
  	}
! 	if ((long)v <= (long)w) {
  		PyTuple_SET_ITEM(pair, 0, PyLong_FromVoidPtr((void *)v));
  		PyTuple_SET_ITEM(pair, 1, PyLong_FromVoidPtr((void *)w));
  	} else {
--- 367,373 ----
  	if (pair == NULL) {
  		return NULL;
  	}
! 	if (v <= w) {
  		PyTuple_SET_ITEM(pair, 0, PyLong_FromVoidPtr((void *)v));
  		PyTuple_SET_ITEM(pair, 1, PyLong_FromVoidPtr((void *)w));
  	} else {

-- 
Trent Mick
trentm@activestate.com