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