/* The PyMem_ family: low-level memory allocation interfaces.
 See objimpl.h for the PyObject_ memory family.
*/

#ifndef Py_PYMEM_H
#define Py_PYMEM_H

#include "pyport.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
 PYMALLOC_DEBUG mode, 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_Realloc(void *ptr, size_t new_size);
PyAPI_FUNC(void) PyMem_Free(void *ptr);

/* Macros. */

/* PyMem_MALLOC(0) means malloc(1). Some systems would return NULL
 for malloc(0), which would be treated as an error. Some platforms
 would return a pointer with no memory behind it, which would break
 pymalloc. To solve these problems, allocate an extra byte. */
/* Returns NULL to indicate error if a negative size or size larger than
 Py_ssize_t can represent is supplied. Helps prevents security holes. */
#define PyMem_MALLOC(n) PyMem_Malloc(n)
#define PyMem_REALLOC(p, n) PyMem_Realloc(p, n)
#define PyMem_FREE(p) PyMem_Free(p)

/*
 * 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)) ) )
#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)) )
#define PyMem_RESIZE(p, type, n) \
 ( (p) = ((size_t)(n) > PY_SSIZE_T_MAX / sizeof(type)) ? NULL : \
 (type *) PyMem_REALLOC((p), (n) * sizeof(type)) )

/* PyMem{Del,DEL} are left over from ancient days, and shouldn't be used
 * anymore. They're just confusing aliases for PyMem_{Free,FREE} now.
 */
#define PyMem_Del PyMem_Free
#define PyMem_DEL PyMem_FREE

/* bpo-35053: expose _Py_tracemalloc_config for performance:
 _Py_NewReference() needs an efficient check to test if tracemalloc is
 tracing.

 It has to be defined in pymem.h, before object.h is included. */
struct _PyTraceMalloc_Config {
 /* Module initialized?
 Variable protected by the GIL */
 enum {
 TRACEMALLOC_NOT_INITIALIZED,
 TRACEMALLOC_INITIALIZED,
 TRACEMALLOC_FINALIZED
 } initialized;

 /* Is tracemalloc tracing memory allocations?
 Variable protected by the GIL */
 int tracing;

 /* limit of the number of frames in a traceback, 1 by default.
 Variable protected by the GIL. */
 int max_nframe;

 /* use domain in trace key?
 Variable protected by the GIL. */
 int use_domain;
};

PyAPI_DATA(struct _PyTraceMalloc_Config) _Py_tracemalloc_config;

#define _PyTraceMalloc_Config_INIT \
 {.initialized = TRACEMALLOC_NOT_INITIALIZED, \
 .tracing = 0, \
 .max_nframe = 1, \
 .use_domain = 0}


#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 */