[Python-checkins] CVS: python/dist/src/Include pymem.h,2.4,2.4.16.1 pyport.h,2.40,2.40.8.1

[Michael Hudson]

Update of /cvsroot/python/python/dist/src/Include
In directory usw-pr-cvs1:/tmp/cvs-serv12181

Modified Files:
      Tag: release22-maint
	pymem.h pyport.h 
Log Message:
backport tim_one's checkin of
    revision 2.5 of pymem.h
    revision 2.44 of pyport.h

Whether platform malloc(0) returns NULL has nothing to do with whether
platform realloc(p, 0) returns NULL, so MALLOC_ZERO_RETURNS_NULL can
be correctly undefined yet realloc(p, 0) can return NULL anyway.

Prevent realloc(p, 0) doing free(p) and returning NULL via a different
hack.  Would probably be better to get rid of MALLOC_ZERO_RETURNS_NULL
entirely.

Bugfix candidate.


Index: pymem.h
===================================================================
RCS file: /cvsroot/python/python/dist/src/Include/pymem.h,v
retrieving revision 2.4
retrieving revision 2.4.16.1
diff -C2 -d -r2.4 -r2.4.16.1
*** pymem.h	26 Jul 2001 21:34:59 -0000	2.4
--- pymem.h	5 Mar 2002 14:24:45 -0000	2.4.16.1
***************
*** 112,122 ****
  #define PyMem_NEW(type, n) \
  	( (type *) PyMem_MALLOC(_PyMem_EXTRA + (n) * sizeof(type)) )
! #define PyMem_RESIZE(p, type, n) \
! 	if ((p) == NULL) \
! 		(p) = (type *)(PyMem_MALLOC( \
! 				    _PyMem_EXTRA + (n) * sizeof(type))); \
! 	else \
! 		(p) = (type *)(PyMem_REALLOC((p), \
! 				    _PyMem_EXTRA + (n) * sizeof(type)))
  #define PyMem_DEL(p) PyMem_FREE(p)
  
--- 112,127 ----
  #define PyMem_NEW(type, n) \
  	( (type *) PyMem_MALLOC(_PyMem_EXTRA + (n) * sizeof(type)) )
! 
! /* See comment near MALLOC_ZERO_RETURNS_NULL in pyport.h. */
! #define PyMem_RESIZE(p, type, n)			\
! 	do {						\
! 		size_t _sum = (n) * sizeof(type);	\
! 		if (!_sum)				\
! 			_sum = 1;			\
! 		(p) = (type *)((p) ?			\
! 			       PyMem_REALLOC(p, _sum) :	\
! 			       PyMem_MALLOC(_sum));	\
! 	} while (0)
! 
  #define PyMem_DEL(p) PyMem_FREE(p)
  

Index: pyport.h
===================================================================
RCS file: /cvsroot/python/python/dist/src/Include/pyport.h,v
retrieving revision 2.40
retrieving revision 2.40.8.1
diff -C2 -d -r2.40 -r2.40.8.1
*** pyport.h	27 Oct 2001 21:16:16 -0000	2.40
--- pyport.h	5 Mar 2002 14:24:45 -0000	2.40.8.1
***************
*** 365,370 ****
  
  #ifdef MALLOC_ZERO_RETURNS_NULL
! /* XXX Always allocate one extra byte, since some malloc's return NULL
!    XXX for malloc(0) or realloc(p, 0). */
  #define _PyMem_EXTRA 1
  #else
--- 365,378 ----
  
  #ifdef MALLOC_ZERO_RETURNS_NULL
! /* Allocate an extra byte if the platform malloc(0) returns NULL.
!    Caution:  this bears no relation to whether realloc(p, 0) returns NULL
!    when p != NULL.  Even on platforms where malloc(0) does not return NULL,
!    realloc(p, 0) may act like free(p) and return NULL.  Examples include
!    Windows, and Python's own obmalloc.c (as of 2-Mar-2002).  For whatever
!    reason, our docs promise that PyMem_Realloc(p, 0) won't act like
!    free(p) or return NULL, so realloc() calls may have to be hacked
!    too, but MALLOC_ZERO_RETURNS_NULL's state is irrelevant to realloc (it
!    needs a different hack).
! */
  #define _PyMem_EXTRA 1
  #else