[OpenSPARC-T2-SAM] / sam-t2 / devtools / v8plus / include / python2.4 / objimpl.h

/* The PyObject_ memory family:  high-level object memory interfaces.
   See pymem.h for the low-level PyMem_ family.
*/

#ifndef Py_OBJIMPL_H
#define Py_OBJIMPL_H

#include "pymem.h"

#ifdef __cplusplus
extern "C" {
#endif

/* BEWARE:

   Each interface exports both functions and macros.  Extension modules should
   use the functions, to ensure binary compatibility across Python versions.
   Because the Python implementation is free to change internal details, and
   the macros may (or may not) expose details for speed, if you do use the
   macros you must recompile your extensions with each Python release.

   Never mix calls to PyObject_ memory functions with calls to the platform
   malloc/realloc/ calloc/free, or with calls to PyMem_.
*/

/*
Functions and macros for modules that implement new object types.

 - PyObject_New(type, typeobj) allocates memory for a new object of the given
   type, and initializes part of it.  'type' must be the C structure type used
   to represent the object, and 'typeobj' the address of the corresponding
   type object.  Reference count and type pointer are filled in; the rest of
   the bytes of the object are *undefined*!  The resulting expression type is
   'type *'.  The size of the object is determined by the tp_basicsize field
   of the type object.

 - PyObject_NewVar(type, typeobj, n) is similar but allocates a variable-size
   object with room for n items.  In addition to the refcount and type pointer
   fields, this also fills in the ob_size field.

 - PyObject_Del(op) releases the memory allocated for an object.  It does not
   run a destructor -- it only frees the memory.  PyObject_Free is identical.

 - PyObject_Init(op, typeobj) and PyObject_InitVar(op, typeobj, n) don't
   allocate memory.  Instead of a 'type' parameter, they take a pointer to a
   new object (allocated by an arbitrary allocator), and initialize its object
   header fields.

Note that objects created with PyObject_{New, NewVar} are allocated using the
specialized Python allocator (implemented in obmalloc.c), if WITH_PYMALLOC is
enabled.  In addition, a special debugging allocator is used if PYMALLOC_DEBUG
is also #defined.

In case a specific form of memory management is needed (for example, if you
must use the platform malloc heap(s), or shared memory, or C++ local storage or
operator new), you must first allocate the object with your custom allocator,
then pass its pointer to PyObject_{Init, InitVar} for filling in its Python-
specific fields:  reference count, type pointer, possibly others.  You should
be aware that Python no control over these objects because they don't
cooperate with the Python memory manager.  Such objects may not be eligible
for automatic garbage collection and you have to make sure that they are
released accordingly whenever their destructor gets called (cf. the specific
form of memory management you're using).

Unless you have specific memory management requirements, use
PyObject_{New, NewVar, Del}.
*/

/*
 * Raw object memory interface
 * ===========================
 */

/* Functions to call the same malloc/realloc/free as used by Python's
   object allocator.  If WITH_PYMALLOC is enabled, these may differ from
   the platform malloc/realloc/free.  The Python object allocator is
   designed for fast, cache-conscious allocation of many "small" objects,
   and with low hidden memory overhead.

   PyObject_Malloc(0) returns a unique non-NULL pointer if possible.

   PyObject_Realloc(NULL, n) acts like PyObject_Malloc(n).
   PyObject_Realloc(p != NULL, 0) does not return  NULL, or free the memory
   at p.

   Returned pointers must be checked for NULL explicitly; no action is
   performed on failure other than to return NULL (no warning it printed, no
   exception is set, etc).

   For allocating objects, use PyObject_{New, NewVar} instead whenever
   possible.  The PyObject_{Malloc, Realloc, Free} family is exposed
   so that you can exploit Python's small-block allocator for non-object
   uses.  If you must use these routines to allocate object memory, make sure
   the object gets initialized via PyObject_{Init, InitVar} after obtaining
   the raw memory.
*/
PyAPI_FUNC(void *) PyObject_Malloc(size_t);
PyAPI_FUNC(void *) PyObject_Realloc(void *, size_t);
PyAPI_FUNC(void) PyObject_Free(void *);


/* Macros */
#ifdef WITH_PYMALLOC
#ifdef PYMALLOC_DEBUG
PyAPI_FUNC(void *) _PyObject_DebugMalloc(size_t nbytes);
PyAPI_FUNC(void *) _PyObject_DebugRealloc(void *p, size_t nbytes);
PyAPI_FUNC(void) _PyObject_DebugFree(void *p);
PyAPI_FUNC(void) _PyObject_DebugDumpAddress(const void *p);
PyAPI_FUNC(void) _PyObject_DebugCheckAddress(const void *p);
PyAPI_FUNC(void) _PyObject_DebugMallocStats(void);
#define PyObject_MALLOC		_PyObject_DebugMalloc
#define PyObject_Malloc		_PyObject_DebugMalloc
#define PyObject_REALLOC	_PyObject_DebugRealloc
#define PyObject_Realloc	_PyObject_DebugRealloc
#define PyObject_FREE		_PyObject_DebugFree
#define PyObject_Free		_PyObject_DebugFree

#else	/* WITH_PYMALLOC && ! PYMALLOC_DEBUG */
#define PyObject_MALLOC		PyObject_Malloc
#define PyObject_REALLOC	PyObject_Realloc
#define PyObject_FREE		PyObject_Free
#endif

#else	/* ! WITH_PYMALLOC */
#define PyObject_MALLOC		PyMem_MALLOC
#define PyObject_REALLOC	PyMem_REALLOC
/* This is an odd one!  For backward compatibility with old extensions, the
   PyMem "release memory" functions have to invoke the object allocator's
   free() function.  When pymalloc isn't enabled, that leaves us using
   the platform free(). */
#define PyObject_FREE		free

#endif	/* WITH_PYMALLOC */

#define PyObject_Del		PyObject_Free
#define PyObject_DEL		PyObject_FREE

/* for source compatibility with 2.2 */
#define _PyObject_Del		PyObject_Free

/*
 * Generic object allocator interface
 * ==================================
 */

/* Functions */
PyAPI_FUNC(PyObject *) PyObject_Init(PyObject *, PyTypeObject *);
PyAPI_FUNC(PyVarObject *) PyObject_InitVar(PyVarObject *,
                                                 PyTypeObject *, int);
PyAPI_FUNC(PyObject *) _PyObject_New(PyTypeObject *);
PyAPI_FUNC(PyVarObject *) _PyObject_NewVar(PyTypeObject *, int);

#define PyObject_New(type, typeobj) \
		( (type *) _PyObject_New(typeobj) )
#define PyObject_NewVar(type, typeobj, n) \
		( (type *) _PyObject_NewVar((typeobj), (n)) )

/* Macros trading binary compatibility for speed. See also pymem.h.
   Note that these macros expect non-NULL object pointers.*/
#define PyObject_INIT(op, typeobj) \
	( (op)->ob_type = (typeobj), _Py_NewReference((PyObject *)(op)), (op) )
#define PyObject_INIT_VAR(op, typeobj, size) \
	( (op)->ob_size = (size), PyObject_INIT((op), (typeobj)) )

#define _PyObject_SIZE(typeobj) ( (typeobj)->tp_basicsize )

/* _PyObject_VAR_SIZE returns the number of bytes (as size_t) allocated for a
   vrbl-size object with nitems items, exclusive of gc overhead (if any).  The
   value is rounded up to the closest multiple of sizeof(void *), in order to
   ensure that pointer fields at the end of the object are correctly aligned
   for the platform (this is of special importance for subclasses of, e.g.,
   str or long, so that pointers can be stored after the embedded data).

   Note that there's no memory wastage in doing this, as malloc has to
   return (at worst) pointer-aligned memory anyway.
*/
#if ((SIZEOF_VOID_P - 1) & SIZEOF_VOID_P) != 0
#   error "_PyObject_VAR_SIZE requires SIZEOF_VOID_P be a power of 2"
#endif

#define _PyObject_VAR_SIZE(typeobj, nitems)	\
	(size_t)				\
	( ( (typeobj)->tp_basicsize +		\
	    (nitems)*(typeobj)->tp_itemsize +	\
	    (SIZEOF_VOID_P - 1)			\
	  ) & ~(SIZEOF_VOID_P - 1)		\
	)

#define PyObject_NEW(type, typeobj) \
( (type *) PyObject_Init( \
	(PyObject *) PyObject_MALLOC( _PyObject_SIZE(typeobj) ), (typeobj)) )

#define PyObject_NEW_VAR(type, typeobj, n) \
( (type *) PyObject_InitVar( \
      (PyVarObject *) PyObject_MALLOC(_PyObject_VAR_SIZE((typeobj),(n)) ),\
      (typeobj), (n)) )

/* This example code implements an object constructor with a custom
   allocator, where PyObject_New is inlined, and shows the important
   distinction between two steps (at least):
       1) the actual allocation of the object storage;
       2) the initialization of the Python specific fields
          in this storage with PyObject_{Init, InitVar}.

   PyObject *
   YourObject_New(...)
   {
       PyObject *op;

       op = (PyObject *) Your_Allocator(_PyObject_SIZE(YourTypeStruct));
       if (op == NULL)
           return PyErr_NoMemory();

       PyObject_Init(op, &YourTypeStruct);

       op->ob_field = value;
       ...
       return op;
   }

   Note that in C++, the use of the new operator usually implies that
   the 1st step is performed automatically for you, so in a C++ class
   constructor you would start directly with PyObject_Init/InitVar
*/

/*
 * Garbage Collection Support
 * ==========================
 */

/* C equivalent of gc.collect(). */
long PyGC_Collect(void);

/* Test if a type has a GC head */
#define PyType_IS_GC(t) PyType_HasFeature((t), Py_TPFLAGS_HAVE_GC)

/* Test if an object has a GC head */
#define PyObject_IS_GC(o) (PyType_IS_GC((o)->ob_type) && \
	((o)->ob_type->tp_is_gc == NULL || (o)->ob_type->tp_is_gc(o)))

PyAPI_FUNC(PyVarObject *) _PyObject_GC_Resize(PyVarObject *, int);
#define PyObject_GC_Resize(type, op, n) \
		( (type *) _PyObject_GC_Resize((PyVarObject *)(op), (n)) )

/* for source compatibility with 2.2 */
#define _PyObject_GC_Del PyObject_GC_Del

/* GC information is stored BEFORE the object structure. */
typedef union _gc_head {
	struct {
		union _gc_head *gc_next;
		union _gc_head *gc_prev;
		int gc_refs;
	} gc;
	long double dummy;  /* force worst-case alignment */
} PyGC_Head;

extern PyGC_Head *_PyGC_generation0;

#define _Py_AS_GC(o) ((PyGC_Head *)(o)-1)

#define _PyGC_REFS_UNTRACKED			(-2)
#define _PyGC_REFS_REACHABLE			(-3)
#define _PyGC_REFS_TENTATIVELY_UNREACHABLE	(-4)

/* Tell the GC to track this object.  NB: While the object is tracked the
 * collector it must be safe to call the ob_traverse method. */
#define _PyObject_GC_TRACK(o) do { \
	PyGC_Head *g = _Py_AS_GC(o); \
	if (g->gc.gc_refs != _PyGC_REFS_UNTRACKED) \
		Py_FatalError("GC object already tracked"); \
	g->gc.gc_refs = _PyGC_REFS_REACHABLE; \
	g->gc.gc_next = _PyGC_generation0; \
	g->gc.gc_prev = _PyGC_generation0->gc.gc_prev; \
	g->gc.gc_prev->gc.gc_next = g; \
	_PyGC_generation0->gc.gc_prev = g; \
    } while (0);

/* Tell the GC to stop tracking this object.
 * gc_next doesn't need to be set to NULL, but doing so is a good
 * way to provoke memory errors if calling code is confused.
 */
#define _PyObject_GC_UNTRACK(o) do { \
	PyGC_Head *g = _Py_AS_GC(o); \
	assert(g->gc.gc_refs != _PyGC_REFS_UNTRACKED); \
	g->gc.gc_refs = _PyGC_REFS_UNTRACKED; \
	g->gc.gc_prev->gc.gc_next = g->gc.gc_next; \
	g->gc.gc_next->gc.gc_prev = g->gc.gc_prev; \
	g->gc.gc_next = NULL; \
    } while (0);

PyAPI_FUNC(PyObject *) _PyObject_GC_Malloc(size_t);
PyAPI_FUNC(PyObject *) _PyObject_GC_New(PyTypeObject *);
PyAPI_FUNC(PyVarObject *) _PyObject_GC_NewVar(PyTypeObject *, int);
PyAPI_FUNC(void) PyObject_GC_Track(void *);
PyAPI_FUNC(void) PyObject_GC_UnTrack(void *);
PyAPI_FUNC(void) PyObject_GC_Del(void *);

#define PyObject_GC_New(type, typeobj) \
		( (type *) _PyObject_GC_New(typeobj) )
#define PyObject_GC_NewVar(type, typeobj, n) \
		( (type *) _PyObject_GC_NewVar((typeobj), (n)) )


/* Utility macro to help write tp_traverse functions.
 * To use this macro, the tp_traverse function must name its arguments
 * "visit" and "arg".  This is intended to keep tp_traverse functions
 * looking as much alike as possible.
 */
#define Py_VISIT(op)					\
        do { 						\
                if (op) {				\
                        int vret = visit((op), arg);	\
                        if (vret)			\
                                return vret;		\
                }					\
        } while (0)

/* This is here for the sake of backwards compatibility.  Extensions that
 * use the old GC API will still compile but the objects will not be
 * tracked by the GC. */
#define PyGC_HEAD_SIZE 0
#define PyObject_GC_Init(op)
#define PyObject_GC_Fini(op)
#define PyObject_AS_GC(op) (op)
#define PyObject_FROM_GC(op) (op)


/* Test if a type supports weak references */
#define PyType_SUPPORTS_WEAKREFS(t) \
        (PyType_HasFeature((t), Py_TPFLAGS_HAVE_WEAKREFS) \
         && ((t)->tp_weaklistoffset > 0))

#define PyObject_GET_WEAKREFS_LISTPTR(o) \
	((PyObject **) (((char *) (o)) + (o)->ob_type->tp_weaklistoffset))

#ifdef __cplusplus
}
#endif
#endif /* !Py_OBJIMPL_H */
Commit	Line	Data
920dae64 AT	1	/* The PyObject_ memory family: high-level object memory interfaces.
	2	See pymem.h for the low-level PyMem_ family.
	3	*/
	4
	5	#ifndef Py_OBJIMPL_H
	6	#define Py_OBJIMPL_H
	7
	8	#include "pymem.h"
	9
	10	#ifdef __cplusplus
	11	extern "C" {
	12	#endif
	13
	14	/* BEWARE:
	15
	16	Each interface exports both functions and macros. Extension modules should
	17	use the functions, to ensure binary compatibility across Python versions.
	18	Because the Python implementation is free to change internal details, and
	19	the macros may (or may not) expose details for speed, if you do use the
	20	macros you must recompile your extensions with each Python release.
	21
	22	Never mix calls to PyObject_ memory functions with calls to the platform
	23	malloc/realloc/ calloc/free, or with calls to PyMem_.
	24	*/
	25
	26	/*
	27	Functions and macros for modules that implement new object types.
	28
	29	- PyObject_New(type, typeobj) allocates memory for a new object of the given
	30	type, and initializes part of it. 'type' must be the C structure type used
	31	to represent the object, and 'typeobj' the address of the corresponding
	32	type object. Reference count and type pointer are filled in; the rest of
	33	the bytes of the object are undefined! The resulting expression type is
	34	'type *'. The size of the object is determined by the tp_basicsize field
	35	of the type object.
	36
	37	- PyObject_NewVar(type, typeobj, n) is similar but allocates a variable-size
	38	object with room for n items. In addition to the refcount and type pointer
	39	fields, this also fills in the ob_size field.
	40
	41	- PyObject_Del(op) releases the memory allocated for an object. It does not
	42	run a destructor -- it only frees the memory. PyObject_Free is identical.
	43
	44	- PyObject_Init(op, typeobj) and PyObject_InitVar(op, typeobj, n) don't
	45	allocate memory. Instead of a 'type' parameter, they take a pointer to a
	46	new object (allocated by an arbitrary allocator), and initialize its object
	47	header fields.
	48
	49	Note that objects created with PyObject_{New, NewVar} are allocated using the
	50	specialized Python allocator (implemented in obmalloc.c), if WITH_PYMALLOC is
	51	enabled. In addition, a special debugging allocator is used if PYMALLOC_DEBUG
	52	is also #defined.
	53
	54	In case a specific form of memory management is needed (for example, if you
	55	must use the platform malloc heap(s), or shared memory, or C++ local storage or
	56	operator new), you must first allocate the object with your custom allocator,
	57	then pass its pointer to PyObject_{Init, InitVar} for filling in its Python-
	58	specific fields: reference count, type pointer, possibly others. You should
	59	be aware that Python no control over these objects because they don't
	60	cooperate with the Python memory manager. Such objects may not be eligible
	61	for automatic garbage collection and you have to make sure that they are
	62	released accordingly whenever their destructor gets called (cf. the specific
	63	form of memory management you're using).
	64
65	Unless you have specific memory management requirements, use
66	PyObject_{New, NewVar, Del}.
67	*/
68
69	/*
70	* Raw object memory interface
71	* ===========================
72	*/
73
74	/* Functions to call the same malloc/realloc/free as used by Python's
75	object allocator. If WITH_PYMALLOC is enabled, these may differ from
76	the platform malloc/realloc/free. The Python object allocator is
77	designed for fast, cache-conscious allocation of many "small" objects,
78	and with low hidden memory overhead.
79
80	PyObject_Malloc(0) returns a unique non-NULL pointer if possible.
81
82	PyObject_Realloc(NULL, n) acts like PyObject_Malloc(n).
83	PyObject_Realloc(p != NULL, 0) does not return NULL, or free the memory
84	at p.
85
86	Returned pointers must be checked for NULL explicitly; no action is
87	performed on failure other than to return NULL (no warning it printed, no
88	exception is set, etc).
89
90	For allocating objects, use PyObject_{New, NewVar} instead whenever
91	possible. The PyObject_{Malloc, Realloc, Free} family is exposed
92	so that you can exploit Python's small-block allocator for non-object
93	uses. If you must use these routines to allocate object memory, make sure
94	the object gets initialized via PyObject_{Init, InitVar} after obtaining
95	the raw memory.
96	*/
97	PyAPI_FUNC(void *) PyObject_Malloc(size_t);
98	PyAPI_FUNC(void ) PyObject_Realloc(void , size_t);
99	PyAPI_FUNC(void) PyObject_Free(void *);
100
101
102	/* Macros */
103	#ifdef WITH_PYMALLOC
104	#ifdef PYMALLOC_DEBUG
105	PyAPI_FUNC(void *) _PyObject_DebugMalloc(size_t nbytes);
106	PyAPI_FUNC(void ) _PyObject_DebugRealloc(void p, size_t nbytes);
107	PyAPI_FUNC(void) _PyObject_DebugFree(void *p);
108	PyAPI_FUNC(void) _PyObject_DebugDumpAddress(const void *p);
109	PyAPI_FUNC(void) _PyObject_DebugCheckAddress(const void *p);
110	PyAPI_FUNC(void) _PyObject_DebugMallocStats(void);
111	#define PyObject_MALLOC _PyObject_DebugMalloc
112	#define PyObject_Malloc _PyObject_DebugMalloc
113	#define PyObject_REALLOC _PyObject_DebugRealloc
114	#define PyObject_Realloc _PyObject_DebugRealloc
115	#define PyObject_FREE _PyObject_DebugFree
116	#define PyObject_Free _PyObject_DebugFree
117
118	#else /* WITH_PYMALLOC && ! PYMALLOC_DEBUG */
119	#define PyObject_MALLOC PyObject_Malloc
120	#define PyObject_REALLOC PyObject_Realloc
121	#define PyObject_FREE PyObject_Free
122	#endif
123
124	#else /* ! WITH_PYMALLOC */
125	#define PyObject_MALLOC PyMem_MALLOC
126	#define PyObject_REALLOC PyMem_REALLOC
127	/* This is an odd one! For backward compatibility with old extensions, the
128	PyMem "release memory" functions have to invoke the object allocator's
129	free() function. When pymalloc isn't enabled, that leaves us using
130	the platform free(). */
131	#define PyObject_FREE free
132
133	#endif /* WITH_PYMALLOC */
134
135	#define PyObject_Del PyObject_Free
136	#define PyObject_DEL PyObject_FREE
137
138	/* for source compatibility with 2.2 */
139	#define _PyObject_Del PyObject_Free
140
141	/*
142	* Generic object allocator interface
143	* ==================================
144	*/
145
146	/* Functions */
147	PyAPI_FUNC(PyObject ) PyObject_Init(PyObject , PyTypeObject *);
148	PyAPI_FUNC(PyVarObject ) PyObject_InitVar(PyVarObject ,
149	PyTypeObject *, int);
150	PyAPI_FUNC(PyObject ) _PyObject_New(PyTypeObject );
151	PyAPI_FUNC(PyVarObject ) _PyObject_NewVar(PyTypeObject , int);
152
153	#define PyObject_New(type, typeobj) \
154	( (type *) _PyObject_New(typeobj) )
155	#define PyObject_NewVar(type, typeobj, n) \
156	( (type *) _PyObject_NewVar((typeobj), (n)) )
157
158	/* Macros trading binary compatibility for speed. See also pymem.h.
159	Note that these macros expect non-NULL object pointers.*/
160	#define PyObject_INIT(op, typeobj) \
161	( (op)->ob_type = (typeobj), _Py_NewReference((PyObject *)(op)), (op) )
162	#define PyObject_INIT_VAR(op, typeobj, size) \
163	( (op)->ob_size = (size), PyObject_INIT((op), (typeobj)) )
164
165	#define _PyObject_SIZE(typeobj) ( (typeobj)->tp_basicsize )
166
167	/* _PyObject_VAR_SIZE returns the number of bytes (as size_t) allocated for a
168	vrbl-size object with nitems items, exclusive of gc overhead (if any). The
169	value is rounded up to the closest multiple of sizeof(void *), in order to
170	ensure that pointer fields at the end of the object are correctly aligned
171	for the platform (this is of special importance for subclasses of, e.g.,
172	str or long, so that pointers can be stored after the embedded data).
173
174	Note that there's no memory wastage in doing this, as malloc has to
175	return (at worst) pointer-aligned memory anyway.
176	*/
177	#if ((SIZEOF_VOID_P - 1) & SIZEOF_VOID_P) != 0
178	# error "_PyObject_VAR_SIZE requires SIZEOF_VOID_P be a power of 2"
179	#endif
180
181	#define _PyObject_VAR_SIZE(typeobj, nitems) \
182	(size_t) \
183	( ( (typeobj)->tp_basicsize + \
184	(nitems)*(typeobj)->tp_itemsize + \
185	(SIZEOF_VOID_P - 1) \
186	) & ~(SIZEOF_VOID_P - 1) \
187	)
188
189	#define PyObject_NEW(type, typeobj) \
190	( (type *) PyObject_Init( \
191	(PyObject *) PyObject_MALLOC( _PyObject_SIZE(typeobj) ), (typeobj)) )
192
193	#define PyObject_NEW_VAR(type, typeobj, n) \
194	( (type *) PyObject_InitVar( \
195	(PyVarObject *) PyObject_MALLOC(_PyObject_VAR_SIZE((typeobj),(n)) ),\
196	(typeobj), (n)) )
197
198	/* This example code implements an object constructor with a custom
199	allocator, where PyObject_New is inlined, and shows the important
200	distinction between two steps (at least):
201	1) the actual allocation of the object storage;
202	2) the initialization of the Python specific fields
203	in this storage with PyObject_{Init, InitVar}.
204
205	PyObject *
206	YourObject_New(...)
207	{
208	PyObject *op;
209
210	op = (PyObject *) Your_Allocator(_PyObject_SIZE(YourTypeStruct));
211	if (op == NULL)
212	return PyErr_NoMemory();
213
214	PyObject_Init(op, &YourTypeStruct);
215
216	op->ob_field = value;
217	...
218	return op;
219	}
220
221	Note that in C++, the use of the new operator usually implies that
222	the 1st step is performed automatically for you, so in a C++ class
223	constructor you would start directly with PyObject_Init/InitVar
224	*/
225
226	/*
227	* Garbage Collection Support
228	* ==========================
229	*/
230
231	/* C equivalent of gc.collect(). */
232	long PyGC_Collect(void);
233
234	/* Test if a type has a GC head */
235	#define PyType_IS_GC(t) PyType_HasFeature((t), Py_TPFLAGS_HAVE_GC)
236
237	/* Test if an object has a GC head */
238	#define PyObject_IS_GC(o) (PyType_IS_GC((o)->ob_type) && \
239	((o)->ob_type->tp_is_gc == NULL \|\| (o)->ob_type->tp_is_gc(o)))
240
241	PyAPI_FUNC(PyVarObject ) _PyObject_GC_Resize(PyVarObject , int);
242	#define PyObject_GC_Resize(type, op, n) \
243	( (type ) _PyObject_GC_Resize((PyVarObject )(op), (n)) )
244
245	/* for source compatibility with 2.2 */
246	#define _PyObject_GC_Del PyObject_GC_Del
247
248	/* GC information is stored BEFORE the object structure. */
249	typedef union _gc_head {
250	struct {
251	union _gc_head *gc_next;
252	union _gc_head *gc_prev;
253	int gc_refs;
254	} gc;
255	long double dummy; /* force worst-case alignment */
256	} PyGC_Head;
257
258	extern PyGC_Head *_PyGC_generation0;
259
260	#define _Py_AS_GC(o) ((PyGC_Head *)(o)-1)
261
262	#define _PyGC_REFS_UNTRACKED (-2)
263	#define _PyGC_REFS_REACHABLE (-3)
264	#define _PyGC_REFS_TENTATIVELY_UNREACHABLE (-4)
265
266	/* Tell the GC to track this object. NB: While the object is tracked the
267	* collector it must be safe to call the ob_traverse method. */
268	#define _PyObject_GC_TRACK(o) do { \
269	PyGC_Head *g = _Py_AS_GC(o); \
270	if (g->gc.gc_refs != _PyGC_REFS_UNTRACKED) \
271	Py_FatalError("GC object already tracked"); \
272	g->gc.gc_refs = _PyGC_REFS_REACHABLE; \
273	g->gc.gc_next = _PyGC_generation0; \
274	g->gc.gc_prev = _PyGC_generation0->gc.gc_prev; \
275	g->gc.gc_prev->gc.gc_next = g; \
276	_PyGC_generation0->gc.gc_prev = g; \
277	} while (0);
278
279	/* Tell the GC to stop tracking this object.
280	* gc_next doesn't need to be set to NULL, but doing so is a good
281	* way to provoke memory errors if calling code is confused.
282	*/
283	#define _PyObject_GC_UNTRACK(o) do { \
284	PyGC_Head *g = _Py_AS_GC(o); \
285	assert(g->gc.gc_refs != _PyGC_REFS_UNTRACKED); \
286	g->gc.gc_refs = _PyGC_REFS_UNTRACKED; \
287	g->gc.gc_prev->gc.gc_next = g->gc.gc_next; \
288	g->gc.gc_next->gc.gc_prev = g->gc.gc_prev; \
289	g->gc.gc_next = NULL; \
290	} while (0);
291
292	PyAPI_FUNC(PyObject *) _PyObject_GC_Malloc(size_t);
293	PyAPI_FUNC(PyObject ) _PyObject_GC_New(PyTypeObject );
294	PyAPI_FUNC(PyVarObject ) _PyObject_GC_NewVar(PyTypeObject , int);
295	PyAPI_FUNC(void) PyObject_GC_Track(void *);
296	PyAPI_FUNC(void) PyObject_GC_UnTrack(void *);
297	PyAPI_FUNC(void) PyObject_GC_Del(void *);
298
299	#define PyObject_GC_New(type, typeobj) \
300	( (type *) _PyObject_GC_New(typeobj) )
301	#define PyObject_GC_NewVar(type, typeobj, n) \
302	( (type *) _PyObject_GC_NewVar((typeobj), (n)) )
303
304
305	/* Utility macro to help write tp_traverse functions.
306	* To use this macro, the tp_traverse function must name its arguments
307	* "visit" and "arg". This is intended to keep tp_traverse functions
308	* looking as much alike as possible.
309	*/
310	#define Py_VISIT(op) \
311	do { \
312	if (op) { \
313	int vret = visit((op), arg); \
314	if (vret) \
315	return vret; \
316	} \
317	} while (0)
318
319	/* This is here for the sake of backwards compatibility. Extensions that
320	* use the old GC API will still compile but the objects will not be
321	* tracked by the GC. */
322	#define PyGC_HEAD_SIZE 0
323	#define PyObject_GC_Init(op)
324	#define PyObject_GC_Fini(op)
325	#define PyObject_AS_GC(op) (op)
326	#define PyObject_FROM_GC(op) (op)
327
328
329	/* Test if a type supports weak references */
330	#define PyType_SUPPORTS_WEAKREFS(t) \
331	(PyType_HasFeature((t), Py_TPFLAGS_HAVE_WEAKREFS) \
332	&& ((t)->tp_weaklistoffset > 0))
333
334	#define PyObject_GET_WEAKREFS_LISTPTR(o) \
335	((PyObject *) (((char ) (o)) + (o)->ob_type->tp_weaklistoffset))
336
337	#ifdef __cplusplus
338	}
339	#endif
340	#endif /* !Py_OBJIMPL_H */