1 /* GLIB - Library of useful routines for C programming
2 * Copyright (C) 1995-1997 Peter Mattis, Spencer Kimball and Josh MacDonald
3 *
4 * SPDX-License-Identifier: LGPL-2.1-or-later
5 *
6 * This library is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
10 *
11 * This library is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Lesser General Public License for more details.
15 *
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with this library; if not, see <http://www.gnu.org/licenses/>.
18 */
19
20 /*
21 * Modified by the GLib Team and others 1997-2000. See the AUTHORS
22 * file for a list of people on the GLib Team. See the ChangeLog
23 * files for a list of changes. These files are distributed with
24 * GLib at ftp://ftp.gtk.org/pub/gtk/.
25 */
26
27 #ifndef __G_MEM_H__
28 #define __G_MEM_H__
29
30 #if !defined (__GLIB_H_INSIDE__) && !defined (GLIB_COMPILATION)
31 #error "Only <glib.h> can be included directly."
32 #endif
33
34 #include <glib/gutils.h>
35 #include <glib/glib-typeof.h>
36
37 G_BEGIN_DECLS
38
39 /**
40 * GMemVTable:
41 * @malloc: function to use for allocating memory.
42 * @realloc: function to use for reallocating memory.
43 * @free: function to use to free memory.
44 * @calloc: function to use for allocating zero-filled memory.
45 * @try_malloc: function to use for allocating memory without a default error handler.
46 * @try_realloc: function to use for reallocating memory without a default error handler.
47 *
48 * A set of functions used to perform memory allocation. The same #GMemVTable must
49 * be used for all allocations in the same program; a call to g_mem_set_vtable(),
50 * if it exists, should be prior to any use of GLib.
51 *
52 * This functions related to this has been deprecated in 2.46, and no longer work.
53 */
54 typedef struct _GMemVTable GMemVTable;
55
56
57 #if GLIB_SIZEOF_VOID_P > GLIB_SIZEOF_LONG
58 /**
59 * G_MEM_ALIGN:
60 *
61 * Indicates the number of bytes to which memory will be aligned on the
62 * current platform.
63 */
64 # define G_MEM_ALIGN GLIB_SIZEOF_VOID_P
65 #else /* GLIB_SIZEOF_VOID_P <= GLIB_SIZEOF_LONG */
66 # define G_MEM_ALIGN GLIB_SIZEOF_LONG
67 #endif /* GLIB_SIZEOF_VOID_P <= GLIB_SIZEOF_LONG */
68
69
70 /* Memory allocation functions
71 */
72
73 GLIB_AVAILABLE_IN_ALL
74 void (g_free) (gpointer mem);
75 GLIB_AVAILABLE_IN_2_76
76 void g_free_sized (gpointer mem,
77 size_t size);
78
79 GLIB_AVAILABLE_IN_2_34
80 void g_clear_pointer (gpointer *pp,
81 GDestroyNotify destroy);
82
83 GLIB_AVAILABLE_IN_ALL
84 gpointer g_malloc (gsize n_bytes) G_GNUC_MALLOC G_GNUC_ALLOC_SIZE(1);
85 GLIB_AVAILABLE_IN_ALL
86 gpointer g_malloc0 (gsize n_bytes) G_GNUC_MALLOC G_GNUC_ALLOC_SIZE(1);
87 GLIB_AVAILABLE_IN_ALL
88 gpointer g_realloc (gpointer mem,
89 gsize n_bytes) G_GNUC_WARN_UNUSED_RESULT;
90 GLIB_AVAILABLE_IN_ALL
91 gpointer g_try_malloc (gsize n_bytes) G_GNUC_MALLOC G_GNUC_ALLOC_SIZE(1);
92 GLIB_AVAILABLE_IN_ALL
93 gpointer g_try_malloc0 (gsize n_bytes) G_GNUC_MALLOC G_GNUC_ALLOC_SIZE(1);
94 GLIB_AVAILABLE_IN_ALL
95 gpointer g_try_realloc (gpointer mem,
96 gsize n_bytes) G_GNUC_WARN_UNUSED_RESULT;
97
98 GLIB_AVAILABLE_IN_ALL
99 gpointer g_malloc_n (gsize n_blocks,
100 gsize n_block_bytes) G_GNUC_MALLOC G_GNUC_ALLOC_SIZE2(1,2);
101 GLIB_AVAILABLE_IN_ALL
102 gpointer g_malloc0_n (gsize n_blocks,
103 gsize n_block_bytes) G_GNUC_MALLOC G_GNUC_ALLOC_SIZE2(1,2);
104 GLIB_AVAILABLE_IN_ALL
105 gpointer g_realloc_n (gpointer mem,
106 gsize n_blocks,
107 gsize n_block_bytes) G_GNUC_WARN_UNUSED_RESULT;
108 GLIB_AVAILABLE_IN_ALL
109 gpointer g_try_malloc_n (gsize n_blocks,
110 gsize n_block_bytes) G_GNUC_MALLOC G_GNUC_ALLOC_SIZE2(1,2);
111 GLIB_AVAILABLE_IN_ALL
112 gpointer g_try_malloc0_n (gsize n_blocks,
113 gsize n_block_bytes) G_GNUC_MALLOC G_GNUC_ALLOC_SIZE2(1,2);
114 GLIB_AVAILABLE_IN_ALL
115 gpointer g_try_realloc_n (gpointer mem,
116 gsize n_blocks,
117 gsize n_block_bytes) G_GNUC_WARN_UNUSED_RESULT;
118
119 GLIB_AVAILABLE_IN_2_72
120 gpointer g_aligned_alloc (gsize n_blocks,
121 gsize n_block_bytes,
122 gsize alignment) G_GNUC_WARN_UNUSED_RESULT G_GNUC_ALLOC_SIZE2(1,2);
123 GLIB_AVAILABLE_IN_2_72
124 gpointer g_aligned_alloc0 (gsize n_blocks,
125 gsize n_block_bytes,
126 gsize alignment) G_GNUC_WARN_UNUSED_RESULT G_GNUC_ALLOC_SIZE2(1,2);
127 GLIB_AVAILABLE_IN_2_72
128 void g_aligned_free (gpointer mem);
129 GLIB_AVAILABLE_IN_2_76
130 void g_aligned_free_sized (gpointer mem,
131 size_t alignment,
132 size_t size);
133
134 #if defined(glib_typeof) && GLIB_VERSION_MAX_ALLOWED >= GLIB_VERSION_2_58
135 #define g_clear_pointer(pp, destroy) \
136 G_STMT_START \
137 { \
138 G_STATIC_ASSERT (sizeof *(pp) == sizeof (gpointer)); \
139 glib_typeof ((pp)) _pp = (pp); \
140 glib_typeof (*(pp)) _ptr = *_pp; \
141 *_pp = NULL; \
142 if (_ptr) \
143 (destroy) (_ptr); \
144 } \
145 G_STMT_END \
146 GLIB_AVAILABLE_MACRO_IN_2_34
147 #else /* __GNUC__ */
148 #define g_clear_pointer(pp, destroy) \
149 G_STMT_START { \
150 G_STATIC_ASSERT (sizeof *(pp) == sizeof (gpointer)); \
151 /* Only one access, please; work around type aliasing */ \
152 union { char *in; gpointer *out; } _pp; \
153 gpointer _p; \
154 /* This assignment is needed to avoid a gcc warning */ \
155 GDestroyNotify _destroy = (GDestroyNotify) (destroy); \
156 \
157 _pp.in = (char *) (pp); \
158 _p = *_pp.out; \
159 if (_p) \
160 { \
161 *_pp.out = NULL; \
162 _destroy (_p); \
163 } \
164 } G_STMT_END \
165 GLIB_AVAILABLE_MACRO_IN_2_34
166 #endif /* __GNUC__ */
167
168
169 #if G_GNUC_CHECK_VERSION (4, 1) && GLIB_VERSION_MAX_ALLOWED >= GLIB_VERSION_2_78 && defined(G_HAVE_FREE_SIZED)
170
171 #define g_free(mem) \
172 (__builtin_object_size ((mem), 0) != ((size_t) - 1)) ? \
173 g_free_sized (mem, __builtin_object_size ((mem), 0)) : (g_free) (mem)
174
175 #endif /* G_GNUC_CHECK_VERSION (4, 1) && && GLIB_VERSION_MAX_ALLOWED >= GLIB_VERSION_2_78 && defined(G_HAVE_FREE_SIZED) */
176
177 /**
178 * g_steal_pointer:
179 * @pp: (not nullable): a pointer to a pointer
180 *
181 * Sets @pp to %NULL, returning the value that was there before.
182 *
183 * Conceptually, this transfers the ownership of the pointer from the
184 * referenced variable to the "caller" of the macro (ie: "steals" the
185 * reference).
186 *
187 * The return value will be properly typed, according to the type of
188 * @pp.
189 *
190 * This can be very useful when combined with g_autoptr() to prevent the
191 * return value of a function from being automatically freed. Consider
192 * the following example (which only works on GCC and clang):
193 *
194 * |[
195 * GObject *
196 * create_object (void)
197 * {
198 * g_autoptr(GObject) obj = g_object_new (G_TYPE_OBJECT, NULL);
199 *
200 * if (early_error_case)
201 * return NULL;
202 *
203 * return g_steal_pointer (&obj);
204 * }
205 * ]|
206 *
207 * It can also be used in similar ways for 'out' parameters and is
208 * particularly useful for dealing with optional out parameters:
209 *
210 * |[
211 * gboolean
212 * get_object (GObject **obj_out)
213 * {
214 * g_autoptr(GObject) obj = g_object_new (G_TYPE_OBJECT, NULL);
215 *
216 * if (early_error_case)
217 * return FALSE;
218 *
219 * if (obj_out)
220 * *obj_out = g_steal_pointer (&obj);
221 *
222 * return TRUE;
223 * }
224 * ]|
225 *
226 * In the above example, the object will be automatically freed in the
227 * early error case and also in the case that %NULL was given for
228 * @obj_out.
229 *
230 * Since: 2.44
231 */
232 GLIB_AVAILABLE_STATIC_INLINE_IN_2_44
233 static inline gpointer
234 g_steal_pointer (gpointer pp)
235 {
236 gpointer *ptr = (gpointer *) pp;
237 gpointer ref;
238
239 ref = *ptr;
240 *ptr = NULL;
241
242 return ref;
243 }
244
245 /* type safety */
246 #if defined(glib_typeof) && GLIB_VERSION_MAX_ALLOWED >= GLIB_VERSION_2_58
247 #define g_steal_pointer(pp) ((glib_typeof (*pp)) (g_steal_pointer) (pp))
248 #else /* __GNUC__ */
249 /* This version does not depend on gcc extensions, but gcc does not warn
250 * about incompatible-pointer-types: */
251 #define g_steal_pointer(pp) \
252 (0 ? (*(pp)) : (g_steal_pointer) (pp))
253 #endif /* __GNUC__ */
254
255 /* Optimise: avoid the call to the (slower) _n function if we can
256 * determine at compile-time that no overflow happens.
257 */
258 #if defined (__GNUC__) && (__GNUC__ >= 2) && defined (__OPTIMIZE__)
259 # define _G_NEW(struct_type, n_structs, func) \
260 (struct_type *) (G_GNUC_EXTENSION ({ \
261 gsize __n = (gsize) (n_structs); \
262 gsize __s = sizeof (struct_type); \
263 gpointer __p; \
264 if (__s == 1) \
265 __p = g_##func (__n); \
266 else if (__builtin_constant_p (__n) && \
267 (__s == 0 || __n <= G_MAXSIZE / __s)) \
268 __p = g_##func (__n * __s); \
269 else \
270 __p = g_##func##_n (__n, __s); \
271 __p; \
272 }))
273 # define _G_RENEW(struct_type, mem, n_structs, func) \
274 (struct_type *) (G_GNUC_EXTENSION ({ \
275 gsize __n = (gsize) (n_structs); \
276 gsize __s = sizeof (struct_type); \
277 gpointer __p = (gpointer) (mem); \
278 if (__s == 1) \
279 __p = g_##func (__p, __n); \
280 else if (__builtin_constant_p (__n) && \
281 (__s == 0 || __n <= G_MAXSIZE / __s)) \
282 __p = g_##func (__p, __n * __s); \
283 else \
284 __p = g_##func##_n (__p, __n, __s); \
285 __p; \
286 }))
287
288 #else
289
290 /* Unoptimised version: always call the _n() function. */
291
292 #define _G_NEW(struct_type, n_structs, func) \
293 ((struct_type *) g_##func##_n ((n_structs), sizeof (struct_type)))
294 #define _G_RENEW(struct_type, mem, n_structs, func) \
295 ((struct_type *) g_##func##_n (mem, (n_structs), sizeof (struct_type)))
296
297 #endif
298
299 /**
300 * g_new:
301 * @struct_type: the type of the elements to allocate
302 * @n_structs: the number of elements to allocate
303 *
304 * Allocates @n_structs elements of type @struct_type.
305 * The returned pointer is cast to a pointer to the given type.
306 * If @n_structs is 0 it returns %NULL.
307 * Care is taken to avoid overflow when calculating the size of the allocated block.
308 *
309 * Since the returned pointer is already casted to the right type,
310 * it is normally unnecessary to cast it explicitly, and doing
311 * so might hide memory allocation errors.
312 *
313 * Returns: a pointer to the allocated memory, cast to a pointer to @struct_type
314 */
315 #define g_new(struct_type, n_structs) _G_NEW (struct_type, n_structs, malloc)
316 /**
317 * g_new0:
318 * @struct_type: the type of the elements to allocate.
319 * @n_structs: the number of elements to allocate.
320 *
321 * Allocates @n_structs elements of type @struct_type, initialized to 0's.
322 * The returned pointer is cast to a pointer to the given type.
323 * If @n_structs is 0 it returns %NULL.
324 * Care is taken to avoid overflow when calculating the size of the allocated block.
325 *
326 * Since the returned pointer is already casted to the right type,
327 * it is normally unnecessary to cast it explicitly, and doing
328 * so might hide memory allocation errors.
329 *
330 * Returns: a pointer to the allocated memory, cast to a pointer to @struct_type.
331 */
332 #define g_new0(struct_type, n_structs) _G_NEW (struct_type, n_structs, malloc0)
333 /**
334 * g_renew:
335 * @struct_type: the type of the elements to allocate
336 * @mem: the currently allocated memory
337 * @n_structs: the number of elements to allocate
338 *
339 * Reallocates the memory pointed to by @mem, so that it now has space for
340 * @n_structs elements of type @struct_type. It returns the new address of
341 * the memory, which may have been moved.
342 * Care is taken to avoid overflow when calculating the size of the allocated block.
343 *
344 * Returns: a pointer to the new allocated memory, cast to a pointer to @struct_type
345 */
346 #define g_renew(struct_type, mem, n_structs) _G_RENEW (struct_type, mem, n_structs, realloc)
347 /**
348 * g_try_new:
349 * @struct_type: the type of the elements to allocate
350 * @n_structs: the number of elements to allocate
351 *
352 * Attempts to allocate @n_structs elements of type @struct_type, and returns
353 * %NULL on failure. Contrast with g_new(), which aborts the program on failure.
354 * The returned pointer is cast to a pointer to the given type.
355 * The function returns %NULL when @n_structs is 0 of if an overflow occurs.
356 *
357 * Since: 2.8
358 * Returns: a pointer to the allocated memory, cast to a pointer to @struct_type
359 */
360 #define g_try_new(struct_type, n_structs) _G_NEW (struct_type, n_structs, try_malloc)
361 /**
362 * g_try_new0:
363 * @struct_type: the type of the elements to allocate
364 * @n_structs: the number of elements to allocate
365 *
366 * Attempts to allocate @n_structs elements of type @struct_type, initialized
367 * to 0's, and returns %NULL on failure. Contrast with g_new0(), which aborts
368 * the program on failure.
369 * The returned pointer is cast to a pointer to the given type.
370 * The function returns %NULL when @n_structs is 0 or if an overflow occurs.
371 *
372 * Since: 2.8
373 * Returns: a pointer to the allocated memory, cast to a pointer to @struct_type
374 */
375 #define g_try_new0(struct_type, n_structs) _G_NEW (struct_type, n_structs, try_malloc0)
376 /**
377 * g_try_renew:
378 * @struct_type: the type of the elements to allocate
379 * @mem: the currently allocated memory
380 * @n_structs: the number of elements to allocate
381 *
382 * Attempts to reallocate the memory pointed to by @mem, so that it now has
383 * space for @n_structs elements of type @struct_type, and returns %NULL on
384 * failure. Contrast with g_renew(), which aborts the program on failure.
385 * It returns the new address of the memory, which may have been moved.
386 * The function returns %NULL if an overflow occurs.
387 *
388 * Since: 2.8
389 * Returns: a pointer to the new allocated memory, cast to a pointer to @struct_type
390 */
391 #define g_try_renew(struct_type, mem, n_structs) _G_RENEW (struct_type, mem, n_structs, try_realloc)
392
393
394 /* Memory allocation virtualization for debugging purposes
395 * g_mem_set_vtable() has to be the very first GLib function called
396 * if being used
397 */
398 struct _GMemVTable {
399 gpointer (*malloc) (gsize n_bytes);
400 gpointer (*realloc) (gpointer mem,
401 gsize n_bytes);
402 void (*free) (gpointer mem);
403 /* optional; set to NULL if not used ! */
404 gpointer (*calloc) (gsize n_blocks,
405 gsize n_block_bytes);
406 gpointer (*try_malloc) (gsize n_bytes);
407 gpointer (*try_realloc) (gpointer mem,
408 gsize n_bytes);
409 };
410 GLIB_DEPRECATED_IN_2_46
411 void g_mem_set_vtable (GMemVTable *vtable);
412 GLIB_DEPRECATED_IN_2_46
413 gboolean g_mem_is_system_malloc (void);
414
415 GLIB_VAR gboolean g_mem_gc_friendly;
416
417 /* Memory profiler and checker, has to be enabled via g_mem_set_vtable()
418 */
419 GLIB_VAR GMemVTable *glib_mem_profiler_table;
420 GLIB_DEPRECATED_IN_2_46
421 void g_mem_profile (void);
422
423 G_END_DECLS
424
425 #endif /* __G_MEM_H__ */