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