mirror of
https://github.com/python/cpython.git
synced 2024-11-27 15:27:06 +01:00
cc71cc9256
Add PyMem_RawMalloc(), PyMem_RawCalloc(), PyMem_RawRealloc() and PyMem_RawFree() to the limited C API. These functions were added by Python 3.4 and are needed to port stdlib extensions to the limited C API, like grp and pwd. Co-authored-by: Erlend E. Aasland <erlend@python.org>
111 lines
4.3 KiB
C
111 lines
4.3 KiB
C
// The PyMem_ family: low-level memory allocation interfaces.
|
|
// See objimpl.h for the PyObject_ memory family.
|
|
|
|
#ifndef Py_PYMEM_H
|
|
#define Py_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 PyMem_ with calls to the platform malloc/realloc/
|
|
calloc/free. For example, on Windows different DLLs may end up using
|
|
different heaps, and if you use PyMem_Malloc you'll get the memory from the
|
|
heap used by the Python DLL; it could be a disaster if you free()'ed that
|
|
directly in your own extension. Using PyMem_Free instead ensures Python
|
|
can return the memory to the proper heap. As another example, in
|
|
a debug build (Py_DEBUG macro), Python wraps all calls to all PyMem_ and
|
|
PyObject_ memory functions in special debugging wrappers that add additional
|
|
debugging info to dynamic memory blocks. The system routines have no idea
|
|
what to do with that stuff, and the Python wrappers have no idea what to do
|
|
with raw blocks obtained directly by the system routines then.
|
|
|
|
The GIL must be held when using these APIs.
|
|
*/
|
|
|
|
/*
|
|
* Raw memory interface
|
|
* ====================
|
|
*/
|
|
|
|
/* Functions
|
|
|
|
Functions supplying platform-independent semantics for malloc/realloc/
|
|
free. These functions make sure that allocating 0 bytes returns a distinct
|
|
non-NULL pointer (whenever possible -- if we're flat out of memory, NULL
|
|
may be returned), even if the platform malloc and realloc don't.
|
|
Returned pointers must be checked for NULL explicitly. No action is
|
|
performed on failure (no exception is set, no warning is printed, etc).
|
|
*/
|
|
|
|
PyAPI_FUNC(void *) PyMem_Malloc(size_t size);
|
|
PyAPI_FUNC(void *) PyMem_Calloc(size_t nelem, size_t elsize);
|
|
PyAPI_FUNC(void *) PyMem_Realloc(void *ptr, size_t new_size);
|
|
PyAPI_FUNC(void) PyMem_Free(void *ptr);
|
|
|
|
/*
|
|
* Type-oriented memory interface
|
|
* ==============================
|
|
*
|
|
* Allocate memory for n objects of the given type. Returns a new pointer
|
|
* or NULL if the request was too large or memory allocation failed. Use
|
|
* these macros rather than doing the multiplication yourself so that proper
|
|
* overflow checking is always done.
|
|
*/
|
|
|
|
#define PyMem_New(type, n) \
|
|
( ((size_t)(n) > PY_SSIZE_T_MAX / sizeof(type)) ? NULL : \
|
|
( (type *) PyMem_Malloc((n) * sizeof(type)) ) )
|
|
|
|
/*
|
|
* The value of (p) is always clobbered by this macro regardless of success.
|
|
* The caller MUST check if (p) is NULL afterwards and deal with the memory
|
|
* error if so. This means the original value of (p) MUST be saved for the
|
|
* caller's memory error handler to not lose track of it.
|
|
*/
|
|
#define PyMem_Resize(p, type, n) \
|
|
( (p) = ((size_t)(n) > PY_SSIZE_T_MAX / sizeof(type)) ? NULL : \
|
|
(type *) PyMem_Realloc((p), (n) * sizeof(type)) )
|
|
|
|
|
|
// Deprecated aliases only kept for backward compatibility.
|
|
// PyMem_Del and PyMem_DEL are defined with no parameter to be able to use
|
|
// them as function pointers (ex: dealloc = PyMem_Del).
|
|
#define PyMem_MALLOC(n) PyMem_Malloc((n))
|
|
#define PyMem_NEW(type, n) PyMem_New(type, (n))
|
|
#define PyMem_REALLOC(p, n) PyMem_Realloc((p), (n))
|
|
#define PyMem_RESIZE(p, type, n) PyMem_Resize((p), type, (n))
|
|
#define PyMem_FREE(p) PyMem_Free((p))
|
|
#define PyMem_Del(p) PyMem_Free((p))
|
|
#define PyMem_DEL(p) PyMem_Free((p))
|
|
|
|
|
|
#if !defined(Py_LIMITED_API) || Py_LIMITED_API+0 >= 0x030d0000
|
|
// Memory allocator which doesn't require the GIL to be held.
|
|
// Usually, it's just a thin wrapper to functions of the standard C library:
|
|
// malloc(), calloc(), realloc() and free(). The difference is that
|
|
// tracemalloc can track these memory allocations.
|
|
PyAPI_FUNC(void *) PyMem_RawMalloc(size_t size);
|
|
PyAPI_FUNC(void *) PyMem_RawCalloc(size_t nelem, size_t elsize);
|
|
PyAPI_FUNC(void *) PyMem_RawRealloc(void *ptr, size_t new_size);
|
|
PyAPI_FUNC(void) PyMem_RawFree(void *ptr);
|
|
#endif
|
|
|
|
#ifndef Py_LIMITED_API
|
|
# define Py_CPYTHON_PYMEM_H
|
|
# include "cpython/pymem.h"
|
|
# undef Py_CPYTHON_PYMEM_H
|
|
#endif
|
|
|
|
#ifdef __cplusplus
|
|
}
|
|
#endif
|
|
#endif // !Py_PYMEM_H
|