forked from python/cpython
-
Notifications
You must be signed in to change notification settings - Fork 0
/
pymem.h
170 lines (129 loc) · 5.06 KB
/
pymem.h
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
/* Lowest-level memory allocation interface */
#ifndef Py_PYMEM_H
#define Py_PYMEM_H
#include "pyport.h"
#ifdef __cplusplus
extern "C" {
#endif
/*
* Core memory allocator
* =====================
*/
/* To make sure the interpreter is user-malloc friendly, all memory
APIs are implemented on top of this one.
The PyCore_* macros can be defined to make the interpreter use a
custom allocator. Note that they are for internal use only. Both
the core and extension modules should use the PyMem_* API.
See the comment block at the end of this file for two scenarios
showing how to use this to use a different allocator. */
#ifndef PyCore_MALLOC_FUNC
#undef PyCore_REALLOC_FUNC
#undef PyCore_FREE_FUNC
#define PyCore_MALLOC_FUNC malloc
#define PyCore_REALLOC_FUNC realloc
#define PyCore_FREE_FUNC free
#endif
#ifndef PyCore_MALLOC_PROTO
#undef PyCore_REALLOC_PROTO
#undef PyCore_FREE_PROTO
#define PyCore_MALLOC_PROTO (size_t)
#define PyCore_REALLOC_PROTO (void *, size_t)
#define PyCore_FREE_PROTO (void *)
#endif
#ifdef NEED_TO_DECLARE_MALLOC_AND_FRIEND
extern void *PyCore_MALLOC_FUNC PyCore_MALLOC_PROTO;
extern void *PyCore_REALLOC_FUNC PyCore_REALLOC_PROTO;
extern void PyCore_FREE_FUNC PyCore_FREE_PROTO;
#endif
#ifndef PyCore_MALLOC
#undef PyCore_REALLOC
#undef PyCore_FREE
#define PyCore_MALLOC(n) PyCore_MALLOC_FUNC(n)
#define PyCore_REALLOC(p, n) PyCore_REALLOC_FUNC((p), (n))
#define PyCore_FREE(p) PyCore_FREE_FUNC(p)
#endif
/* BEWARE:
Each interface exports both functions and macros. Extension modules
should normally use the functions for ensuring binary compatibility
of the user's code across Python versions. Subsequently, if the
Python runtime switches to its own malloc (different from standard
malloc), no recompilation is required for the extensions.
The macro versions trade compatibility for speed. They can be used
whenever there is a performance problem, but their use implies
recompilation of the code for each new Python release. The Python
core uses the macros because it *is* compiled on every upgrade.
This might not be the case with 3rd party extensions in a custom
setup (for example, a customer does not always have access to the
source of 3rd party deliverables). You have been warned! */
/*
* Raw memory interface
* ====================
*/
/* Functions */
/* Function wrappers around PyCore_MALLOC and friends; useful if you
need to be sure that you are using the same memory allocator as
Python. Note that the wrappers make sure that allocating 0 bytes
returns a non-NULL pointer, even if the underlying malloc
doesn't. Returned pointers must be checked for NULL explicitly.
No action is performed on failure. */
extern DL_IMPORT(void *) PyMem_Malloc(size_t);
extern DL_IMPORT(void *) PyMem_Realloc(void *, size_t);
extern DL_IMPORT(void) PyMem_Free(void *);
/* Starting from Python 1.6, the wrappers Py_{Malloc,Realloc,Free} are
no longer supported. They used to call PyErr_NoMemory() on failure. */
/* Macros */
#define PyMem_MALLOC(n) PyCore_MALLOC(n)
#define PyMem_REALLOC(p, n) PyCore_REALLOC((void *)(p), (n))
#define PyMem_FREE(p) PyCore_FREE((void *)(p))
/*
* Type-oriented memory interface
* ==============================
*/
/* Functions */
#define PyMem_New(type, n) \
( (type *) PyMem_Malloc((n) * sizeof(type)) )
#define PyMem_Resize(p, type, n) \
( (p) = (type *) PyMem_Realloc((p), (n) * sizeof(type)) )
#define PyMem_Del(p) PyMem_Free(p)
/* Macros */
#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)
/* PyMem_XDEL is deprecated. To avoid the call when p is NULL,
it is recommended to write the test explicitly in the code.
Note that according to ANSI C, free(NULL) has no effect. */
#ifdef __cplusplus
}
#endif
/* SCENARIOS
Here are two scenarios by Vladimir Marangozov (the author of the
memory allocation redesign).
1) Scenario A
Suppose you want to use a debugging malloc library that collects info on
where the malloc calls originate from. Assume the interface is:
d_malloc(size_t n, char* src_file, unsigned long src_line) c.s.
In this case, you would define (for example in config.h) :
#define PyCore_MALLOC_FUNC d_malloc
...
#define PyCore_MALLOC_PROTO (size_t, char *, unsigned long)
...
#define NEED_TO_DECLARE_MALLOC_AND_FRIEND
#define PyCore_MALLOC(n) PyCore_MALLOC_FUNC((n), __FILE__, __LINE__)
...
2) Scenario B
Suppose you want to use malloc hooks (defined & initialized in a 3rd party
malloc library) instead of malloc functions. In this case, you would
define:
#define PyCore_MALLOC_FUNC (*malloc_hook)
...
#define NEED_TO_DECLARE_MALLOC_AND_FRIEND
and ignore the previous definitions about PyCore_MALLOC_FUNC, etc.
*/
#endif /* !Py_PYMEM_H */