1 /* GLIB - Library of useful routines for C programming
2 * Copyright (C) 1995-1997 Peter Mattis, Spencer Kimball and Josh MacDonald
3 *
4 * This library is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU Lesser General Public
6 * License as published by the Free Software Foundation; either
7 * version 2.1 of the License, or (at your option) any later version.
8 *
9 * This library is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * Lesser General Public License for more details.
13 *
14 * You should have received a copy of the GNU Lesser General Public
15 * License along with this library; if not, see <http://www.gnu.org/licenses/>.
16 */
17
18 /*
19 * Modified by the GLib Team and others 1997-2000. See the AUTHORS
20 * file for a list of people on the GLib Team. See the ChangeLog
21 * files for a list of changes. These files are distributed with
22 * GLib at ftp://ftp.gtk.org/pub/gtk/.
23 */
24
25 #ifndef __G_MEM_H__
26 #define __G_MEM_H__
27
28 #if !defined (__GLIB_H_INSIDE__) && !defined (GLIB_COMPILATION)
29 #error "Only <glib.h> can be included directly."
30 #endif
31
32 #include <glib/gutils.h>
33
34 #if defined(glib_typeof_2_68) && GLIB_VERSION_MIN_REQUIRED >= GLIB_VERSION_2_68
35 /* for glib_typeof */
36 #include <type_traits>
37 #endif
38
39 G_BEGIN_DECLS
40
41 /**
42 * GMemVTable:
43 * @malloc: function to use for allocating memory.
44 * @realloc: function to use for reallocating memory.
45 * @free: function to use to free memory.
46 * @calloc: function to use for allocating zero-filled memory.
47 * @try_malloc: function to use for allocating memory without a default error handler.
48 * @try_realloc: function to use for reallocating memory without a default error handler.
49 *
50 * A set of functions used to perform memory allocation. The same #GMemVTable must
51 * be used for all allocations in the same program; a call to g_mem_set_vtable(),
52 * if it exists, should be prior to any use of GLib.
53 *
54 * This functions related to this has been deprecated in 2.46, and no longer work.
55 */
56 typedef struct _GMemVTable GMemVTable;
57
58
59 #if GLIB_SIZEOF_VOID_P > GLIB_SIZEOF_LONG
60 /**
61 * G_MEM_ALIGN:
62 *
63 * Indicates the number of bytes to which memory will be aligned on the
64 * current platform.
65 */
66 # define G_MEM_ALIGN GLIB_SIZEOF_VOID_P
67 #else /* GLIB_SIZEOF_VOID_P <= GLIB_SIZEOF_LONG */
68 # define G_MEM_ALIGN GLIB_SIZEOF_LONG
69 #endif /* GLIB_SIZEOF_VOID_P <= GLIB_SIZEOF_LONG */
70
71
72 /* Memory allocation functions
73 */
74
75 GLIB_AVAILABLE_IN_ALL
76 void g_free (gpointer mem);
77
78 GLIB_AVAILABLE_IN_2_34
79 void g_clear_pointer (gpointer *pp,
80 GDestroyNotify destroy);
81
82 GLIB_AVAILABLE_IN_ALL
83 gpointer g_malloc (gsize n_bytes) G_GNUC_MALLOC G_GNUC_ALLOC_SIZE(1);
84 GLIB_AVAILABLE_IN_ALL
85 gpointer g_malloc0 (gsize n_bytes) G_GNUC_MALLOC G_GNUC_ALLOC_SIZE(1);
86 GLIB_AVAILABLE_IN_ALL
87 gpointer g_realloc (gpointer mem,
88 gsize n_bytes) G_GNUC_WARN_UNUSED_RESULT;
89 GLIB_AVAILABLE_IN_ALL
90 gpointer g_try_malloc (gsize n_bytes) G_GNUC_MALLOC G_GNUC_ALLOC_SIZE(1);
91 GLIB_AVAILABLE_IN_ALL
92 gpointer g_try_malloc0 (gsize n_bytes) G_GNUC_MALLOC G_GNUC_ALLOC_SIZE(1);
93 GLIB_AVAILABLE_IN_ALL
94 gpointer g_try_realloc (gpointer mem,
95 gsize n_bytes) G_GNUC_WARN_UNUSED_RESULT;
96
97 GLIB_AVAILABLE_IN_ALL
98 gpointer g_malloc_n (gsize n_blocks,
99 gsize n_block_bytes) G_GNUC_MALLOC G_GNUC_ALLOC_SIZE2(1,2);
100 GLIB_AVAILABLE_IN_ALL
101 gpointer g_malloc0_n (gsize n_blocks,
102 gsize n_block_bytes) G_GNUC_MALLOC G_GNUC_ALLOC_SIZE2(1,2);
103 GLIB_AVAILABLE_IN_ALL
104 gpointer g_realloc_n (gpointer mem,
105 gsize n_blocks,
106 gsize n_block_bytes) G_GNUC_WARN_UNUSED_RESULT;
107 GLIB_AVAILABLE_IN_ALL
108 gpointer g_try_malloc_n (gsize n_blocks,
109 gsize n_block_bytes) G_GNUC_MALLOC G_GNUC_ALLOC_SIZE2(1,2);
110 GLIB_AVAILABLE_IN_ALL
111 gpointer g_try_malloc0_n (gsize n_blocks,
112 gsize n_block_bytes) G_GNUC_MALLOC G_GNUC_ALLOC_SIZE2(1,2);
113 GLIB_AVAILABLE_IN_ALL
114 gpointer g_try_realloc_n (gpointer mem,
115 gsize n_blocks,
116 gsize n_block_bytes) G_GNUC_WARN_UNUSED_RESULT;
117
118 #if defined(glib_typeof) && GLIB_VERSION_MAX_ALLOWED >= GLIB_VERSION_2_58 && (!defined(glib_typeof_2_68) || GLIB_VERSION_MIN_REQUIRED >= GLIB_VERSION_2_68)
119 #define g_clear_pointer(pp, destroy) \
120 G_STMT_START \
121 { \
122 G_STATIC_ASSERT (sizeof *(pp) == sizeof (gpointer)); \
123 glib_typeof ((pp)) _pp = (pp); \
124 glib_typeof (*(pp)) _ptr = *_pp; \
125 *_pp = NULL; \
126 if (_ptr) \
127 (destroy) (_ptr); \
128 } \
129 G_STMT_END \
130 GLIB_AVAILABLE_MACRO_IN_2_34
131 #else /* __GNUC__ */
132 #define g_clear_pointer(pp, destroy) \
133 G_STMT_START { \
134 G_STATIC_ASSERT (sizeof *(pp) == sizeof (gpointer)); \
135 /* Only one access, please; work around type aliasing */ \
136 union { char *in; gpointer *out; } _pp; \
137 gpointer _p; \
138 /* This assignment is needed to avoid a gcc warning */ \
139 GDestroyNotify _destroy = (GDestroyNotify) (destroy); \
140 \
141 _pp.in = (char *) (pp); \
142 _p = *_pp.out; \
143 if (_p) \
144 { \
145 *_pp.out = NULL; \
146 _destroy (_p); \
147 } \
148 } G_STMT_END \
149 GLIB_AVAILABLE_MACRO_IN_2_34
150 #endif /* __GNUC__ */
151
152 /**
153 * g_steal_pointer:
154 * @pp: (not nullable): a pointer to a pointer
155 *
156 * Sets @pp to %NULL, returning the value that was there before.
157 *
158 * Conceptually, this transfers the ownership of the pointer from the
159 * referenced variable to the "caller" of the macro (ie: "steals" the
160 * reference).
161 *
162 * The return value will be properly typed, according to the type of
163 * @pp.
164 *
165 * This can be very useful when combined with g_autoptr() to prevent the
166 * return value of a function from being automatically freed. Consider
167 * the following example (which only works on GCC and clang):
168 *
169 * |[
170 * GObject *
171 * create_object (void)
172 * {
173 * g_autoptr(GObject) obj = g_object_new (G_TYPE_OBJECT, NULL);
174 *
175 * if (early_error_case)
176 * return NULL;
177 *
178 * return g_steal_pointer (&obj);
179 * }
180 * ]|
181 *
182 * It can also be used in similar ways for 'out' parameters and is
183 * particularly useful for dealing with optional out parameters:
184 *
185 * |[
186 * gboolean
187 * get_object (GObject **obj_out)
188 * {
189 * g_autoptr(GObject) obj = g_object_new (G_TYPE_OBJECT, NULL);
190 *
191 * if (early_error_case)
192 * return FALSE;
193 *
194 * if (obj_out)
195 * *obj_out = g_steal_pointer (&obj);
196 *
197 * return TRUE;
198 * }
199 * ]|
200 *
201 * In the above example, the object will be automatically freed in the
202 * early error case and also in the case that %NULL was given for
203 * @obj_out.
204 *
205 * Since: 2.44
206 */
207 GLIB_AVAILABLE_STATIC_INLINE_IN_2_44
208 static inline gpointer
g_steal_pointer(gpointer pp)209 g_steal_pointer (gpointer pp)
210 {
211 gpointer *ptr = (gpointer *) pp;
212 gpointer ref;
213
214 ref = *ptr;
215 *ptr = NULL;
216
217 return ref;
218 }
219
220 /* type safety */
221 #if defined(glib_typeof) && GLIB_VERSION_MAX_ALLOWED >= GLIB_VERSION_2_58 && (!defined(glib_typeof_2_68) || GLIB_VERSION_MIN_REQUIRED >= GLIB_VERSION_2_68)
222 #define g_steal_pointer(pp) ((glib_typeof (*pp)) (g_steal_pointer) (pp))
223 #else /* __GNUC__ */
224 /* This version does not depend on gcc extensions, but gcc does not warn
225 * about incompatible-pointer-types: */
226 #define g_steal_pointer(pp) \
227 (0 ? (*(pp)) : (g_steal_pointer) (pp))
228 #endif /* __GNUC__ */
229
230 /* Optimise: avoid the call to the (slower) _n function if we can
231 * determine at compile-time that no overflow happens.
232 */
233 #if defined (__GNUC__) && (__GNUC__ >= 2) && defined (__OPTIMIZE__)
234 # define _G_NEW(struct_type, n_structs, func) \
235 (struct_type *) (G_GNUC_EXTENSION ({ \
236 gsize __n = (gsize) (n_structs); \
237 gsize __s = sizeof (struct_type); \
238 gpointer __p; \
239 if (__s == 1) \
240 __p = g_##func (__n); \
241 else if (__builtin_constant_p (__n) && \
242 (__s == 0 || __n <= G_MAXSIZE / __s)) \
243 __p = g_##func (__n * __s); \
244 else \
245 __p = g_##func##_n (__n, __s); \
246 __p; \
247 }))
248 # define _G_RENEW(struct_type, mem, n_structs, func) \
249 (struct_type *) (G_GNUC_EXTENSION ({ \
250 gsize __n = (gsize) (n_structs); \
251 gsize __s = sizeof (struct_type); \
252 gpointer __p = (gpointer) (mem); \
253 if (__s == 1) \
254 __p = g_##func (__p, __n); \
255 else if (__builtin_constant_p (__n) && \
256 (__s == 0 || __n <= G_MAXSIZE / __s)) \
257 __p = g_##func (__p, __n * __s); \
258 else \
259 __p = g_##func##_n (__p, __n, __s); \
260 __p; \
261 }))
262
263 #else
264
265 /* Unoptimised version: always call the _n() function. */
266
267 #define _G_NEW(struct_type, n_structs, func) \
268 ((struct_type *) g_##func##_n ((n_structs), sizeof (struct_type)))
269 #define _G_RENEW(struct_type, mem, n_structs, func) \
270 ((struct_type *) g_##func##_n (mem, (n_structs), sizeof (struct_type)))
271
272 #endif
273
274 /**
275 * g_new:
276 * @struct_type: the type of the elements to allocate
277 * @n_structs: the number of elements to allocate
278 *
279 * Allocates @n_structs elements of type @struct_type.
280 * The returned pointer is cast to a pointer to the given type.
281 * If @n_structs is 0 it returns %NULL.
282 * Care is taken to avoid overflow when calculating the size of the allocated block.
283 *
284 * Since the returned pointer is already casted to the right type,
285 * it is normally unnecessary to cast it explicitly, and doing
286 * so might hide memory allocation errors.
287 *
288 * Returns: a pointer to the allocated memory, cast to a pointer to @struct_type
289 */
290 #define g_new(struct_type, n_structs) _G_NEW (struct_type, n_structs, malloc)
291 /**
292 * g_new0:
293 * @struct_type: the type of the elements to allocate.
294 * @n_structs: the number of elements to allocate.
295 *
296 * Allocates @n_structs elements of type @struct_type, initialized to 0's.
297 * The returned pointer is cast to a pointer to the given type.
298 * If @n_structs is 0 it returns %NULL.
299 * Care is taken to avoid overflow when calculating the size of the allocated block.
300 *
301 * Since the returned pointer is already casted to the right type,
302 * it is normally unnecessary to cast it explicitly, and doing
303 * so might hide memory allocation errors.
304 *
305 * Returns: a pointer to the allocated memory, cast to a pointer to @struct_type.
306 */
307 #define g_new0(struct_type, n_structs) _G_NEW (struct_type, n_structs, malloc0)
308 /**
309 * g_renew:
310 * @struct_type: the type of the elements to allocate
311 * @mem: the currently allocated memory
312 * @n_structs: the number of elements to allocate
313 *
314 * Reallocates the memory pointed to by @mem, so that it now has space for
315 * @n_structs elements of type @struct_type. It returns the new address of
316 * the memory, which may have been moved.
317 * Care is taken to avoid overflow when calculating the size of the allocated block.
318 *
319 * Returns: a pointer to the new allocated memory, cast to a pointer to @struct_type
320 */
321 #define g_renew(struct_type, mem, n_structs) _G_RENEW (struct_type, mem, n_structs, realloc)
322 /**
323 * g_try_new:
324 * @struct_type: the type of the elements to allocate
325 * @n_structs: the number of elements to allocate
326 *
327 * Attempts to allocate @n_structs elements of type @struct_type, and returns
328 * %NULL on failure. Contrast with g_new(), which aborts the program on failure.
329 * The returned pointer is cast to a pointer to the given type.
330 * The function returns %NULL when @n_structs is 0 of if an overflow occurs.
331 *
332 * Since: 2.8
333 * Returns: a pointer to the allocated memory, cast to a pointer to @struct_type
334 */
335 #define g_try_new(struct_type, n_structs) _G_NEW (struct_type, n_structs, try_malloc)
336 /**
337 * g_try_new0:
338 * @struct_type: the type of the elements to allocate
339 * @n_structs: the number of elements to allocate
340 *
341 * Attempts to allocate @n_structs elements of type @struct_type, initialized
342 * to 0's, and returns %NULL on failure. Contrast with g_new0(), which aborts
343 * the program on failure.
344 * The returned pointer is cast to a pointer to the given type.
345 * The function returns %NULL when @n_structs is 0 or if an overflow occurs.
346 *
347 * Since: 2.8
348 * Returns: a pointer to the allocated memory, cast to a pointer to @struct_type
349 */
350 #define g_try_new0(struct_type, n_structs) _G_NEW (struct_type, n_structs, try_malloc0)
351 /**
352 * g_try_renew:
353 * @struct_type: the type of the elements to allocate
354 * @mem: the currently allocated memory
355 * @n_structs: the number of elements to allocate
356 *
357 * Attempts to reallocate the memory pointed to by @mem, so that it now has
358 * space for @n_structs elements of type @struct_type, and returns %NULL on
359 * failure. Contrast with g_renew(), which aborts the program on failure.
360 * It returns the new address of the memory, which may have been moved.
361 * The function returns %NULL if an overflow occurs.
362 *
363 * Since: 2.8
364 * Returns: a pointer to the new allocated memory, cast to a pointer to @struct_type
365 */
366 #define g_try_renew(struct_type, mem, n_structs) _G_RENEW (struct_type, mem, n_structs, try_realloc)
367
368
369 /* Memory allocation virtualization for debugging purposes
370 * g_mem_set_vtable() has to be the very first GLib function called
371 * if being used
372 */
373 struct _GMemVTable {
374 gpointer (*malloc) (gsize n_bytes);
375 gpointer (*realloc) (gpointer mem,
376 gsize n_bytes);
377 void (*free) (gpointer mem);
378 /* optional; set to NULL if not used ! */
379 gpointer (*calloc) (gsize n_blocks,
380 gsize n_block_bytes);
381 gpointer (*try_malloc) (gsize n_bytes);
382 gpointer (*try_realloc) (gpointer mem,
383 gsize n_bytes);
384 };
385 GLIB_DEPRECATED_IN_2_46
386 void g_mem_set_vtable (GMemVTable *vtable);
387 GLIB_DEPRECATED_IN_2_46
388 gboolean g_mem_is_system_malloc (void);
389
390 GLIB_VAR gboolean g_mem_gc_friendly;
391
392 /* Memory profiler and checker, has to be enabled via g_mem_set_vtable()
393 */
394 GLIB_VAR GMemVTable *glib_mem_profiler_table;
395 GLIB_DEPRECATED_IN_2_46
396 void g_mem_profile (void);
397
398 G_END_DECLS
399
400 #endif /* __G_MEM_H__ */
401