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
37G_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 */
54typedef 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
73GLIB_AVAILABLE_IN_ALL
74void (g_free) (gpointer mem);
75GLIB_AVAILABLE_IN_2_76
76void g_free_sized (gpointer mem,
77 size_t size);
78
79GLIB_AVAILABLE_IN_2_34
80void g_clear_pointer (gpointer *pp,
81 GDestroyNotify destroy);
82
83GLIB_AVAILABLE_IN_ALL
84gpointer g_malloc (gsize n_bytes) G_GNUC_MALLOC G_GNUC_ALLOC_SIZE(1);
85GLIB_AVAILABLE_IN_ALL
86gpointer g_malloc0 (gsize n_bytes) G_GNUC_MALLOC G_GNUC_ALLOC_SIZE(1);
87GLIB_AVAILABLE_IN_ALL
88gpointer g_realloc (gpointer mem,
89 gsize n_bytes) G_GNUC_WARN_UNUSED_RESULT;
90GLIB_AVAILABLE_IN_ALL
91gpointer g_try_malloc (gsize n_bytes) G_GNUC_MALLOC G_GNUC_ALLOC_SIZE(1);
92GLIB_AVAILABLE_IN_ALL
93gpointer g_try_malloc0 (gsize n_bytes) G_GNUC_MALLOC G_GNUC_ALLOC_SIZE(1);
94GLIB_AVAILABLE_IN_ALL
95gpointer g_try_realloc (gpointer mem,
96 gsize n_bytes) G_GNUC_WARN_UNUSED_RESULT;
97
98GLIB_AVAILABLE_IN_ALL
99gpointer g_malloc_n (gsize n_blocks,
100 gsize n_block_bytes) G_GNUC_MALLOC G_GNUC_ALLOC_SIZE2(1,2);
101GLIB_AVAILABLE_IN_ALL
102gpointer g_malloc0_n (gsize n_blocks,
103 gsize n_block_bytes) G_GNUC_MALLOC G_GNUC_ALLOC_SIZE2(1,2);
104GLIB_AVAILABLE_IN_ALL
105gpointer g_realloc_n (gpointer mem,
106 gsize n_blocks,
107 gsize n_block_bytes) G_GNUC_WARN_UNUSED_RESULT;
108GLIB_AVAILABLE_IN_ALL
109gpointer g_try_malloc_n (gsize n_blocks,
110 gsize n_block_bytes) G_GNUC_MALLOC G_GNUC_ALLOC_SIZE2(1,2);
111GLIB_AVAILABLE_IN_ALL
112gpointer g_try_malloc0_n (gsize n_blocks,
113 gsize n_block_bytes) G_GNUC_MALLOC G_GNUC_ALLOC_SIZE2(1,2);
114GLIB_AVAILABLE_IN_ALL
115gpointer g_try_realloc_n (gpointer mem,
116 gsize n_blocks,
117 gsize n_block_bytes) G_GNUC_WARN_UNUSED_RESULT;
118
119GLIB_AVAILABLE_IN_2_72
120gpointer 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);
123GLIB_AVAILABLE_IN_2_72
124gpointer 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);
127GLIB_AVAILABLE_IN_2_72
128void g_aligned_free (gpointer mem);
129GLIB_AVAILABLE_IN_2_76
130void 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 */
232GLIB_AVAILABLE_STATIC_INLINE_IN_2_44
233static inline gpointer g_steal_pointer (gpointer pp);
234
235GLIB_AVAILABLE_STATIC_INLINE_IN_2_44
236static inline gpointer
237g_steal_pointer (gpointer pp)
238{
239 gpointer *ptr = (gpointer *) pp;
240 gpointer ref;
241
242 ref = *ptr;
243 *ptr = NULL;
244
245 return ref;
246}
247
248/* type safety */
249#if defined(glib_typeof) && GLIB_VERSION_MAX_ALLOWED >= GLIB_VERSION_2_58
250#define g_steal_pointer(pp) ((glib_typeof (*pp)) (g_steal_pointer) (pp))
251#else /* __GNUC__ */
252/* This version does not depend on gcc extensions, but gcc does not warn
253 * about incompatible-pointer-types: */
254#define g_steal_pointer(pp) \
255 (0 ? (*(pp)) : (g_steal_pointer) (pp))
256#endif /* __GNUC__ */
257
258/* Optimise: avoid the call to the (slower) _n function if we can
259 * determine at compile-time that no overflow happens.
260 */
261#if defined (__GNUC__) && (__GNUC__ >= 2) && defined (__OPTIMIZE__)
262# define _G_NEW(struct_type, n_structs, func) \
263 (struct_type *) (G_GNUC_EXTENSION ({ \
264 gsize __n = (gsize) (n_structs); \
265 gsize __s = sizeof (struct_type); \
266 gpointer __p; \
267 if (__s == 1) \
268 __p = g_##func (__n); \
269 else if (__builtin_constant_p (__n) && \
270 (__s == 0 || __n <= G_MAXSIZE / __s)) \
271 __p = g_##func (__n * __s); \
272 else \
273 __p = g_##func##_n (__n, __s); \
274 __p; \
275 }))
276# define _G_RENEW(struct_type, mem, n_structs, func) \
277 (struct_type *) (G_GNUC_EXTENSION ({ \
278 gsize __n = (gsize) (n_structs); \
279 gsize __s = sizeof (struct_type); \
280 gpointer __p = (gpointer) (mem); \
281 if (__s == 1) \
282 __p = g_##func (__p, __n); \
283 else if (__builtin_constant_p (__n) && \
284 (__s == 0 || __n <= G_MAXSIZE / __s)) \
285 __p = g_##func (__p, __n * __s); \
286 else \
287 __p = g_##func##_n (__p, __n, __s); \
288 __p; \
289 }))
290
291#else
292
293/* Unoptimised version: always call the _n() function. */
294
295#define _G_NEW(struct_type, n_structs, func) \
296 ((struct_type *) g_##func##_n ((n_structs), sizeof (struct_type)))
297#define _G_RENEW(struct_type, mem, n_structs, func) \
298 ((struct_type *) g_##func##_n (mem, (n_structs), sizeof (struct_type)))
299
300#endif
301
302/**
303 * g_new:
304 * @struct_type: the type of the elements to allocate
305 * @n_structs: the number of elements to allocate
306 *
307 * Allocates @n_structs elements of type @struct_type.
308 * The returned pointer is cast to a pointer to the given type.
309 * If @n_structs is 0 it returns %NULL.
310 * Care is taken to avoid overflow when calculating the size of the allocated block.
311 *
312 * Since the returned pointer is already casted to the right type,
313 * it is normally unnecessary to cast it explicitly, and doing
314 * so might hide memory allocation errors.
315 *
316 * Returns: a pointer to the allocated memory, cast to a pointer to @struct_type
317 */
318#define g_new(struct_type, n_structs) _G_NEW (struct_type, n_structs, malloc)
319/**
320 * g_new0:
321 * @struct_type: the type of the elements to allocate.
322 * @n_structs: the number of elements to allocate.
323 *
324 * Allocates @n_structs elements of type @struct_type, initialized to 0's.
325 * The returned pointer is cast to a pointer to the given type.
326 * If @n_structs is 0 it returns %NULL.
327 * Care is taken to avoid overflow when calculating the size of the allocated block.
328 *
329 * Since the returned pointer is already casted to the right type,
330 * it is normally unnecessary to cast it explicitly, and doing
331 * so might hide memory allocation errors.
332 *
333 * Returns: a pointer to the allocated memory, cast to a pointer to @struct_type.
334 */
335#define g_new0(struct_type, n_structs) _G_NEW (struct_type, n_structs, malloc0)
336/**
337 * g_renew:
338 * @struct_type: the type of the elements to allocate
339 * @mem: the currently allocated memory
340 * @n_structs: the number of elements to allocate
341 *
342 * Reallocates the memory pointed to by @mem, so that it now has space for
343 * @n_structs elements of type @struct_type. It returns the new address of
344 * the memory, which may have been moved.
345 * Care is taken to avoid overflow when calculating the size of the allocated block.
346 *
347 * Returns: a pointer to the new allocated memory, cast to a pointer to @struct_type
348 */
349#define g_renew(struct_type, mem, n_structs) _G_RENEW (struct_type, mem, n_structs, realloc)
350/**
351 * g_try_new:
352 * @struct_type: the type of the elements to allocate
353 * @n_structs: the number of elements to allocate
354 *
355 * Attempts to allocate @n_structs elements of type @struct_type, and returns
356 * %NULL on failure. Contrast with g_new(), which aborts the program on failure.
357 * The returned pointer is cast to a pointer to the given type.
358 * The function returns %NULL when @n_structs is 0 of if an overflow occurs.
359 *
360 * Since: 2.8
361 * Returns: a pointer to the allocated memory, cast to a pointer to @struct_type
362 */
363#define g_try_new(struct_type, n_structs) _G_NEW (struct_type, n_structs, try_malloc)
364/**
365 * g_try_new0:
366 * @struct_type: the type of the elements to allocate
367 * @n_structs: the number of elements to allocate
368 *
369 * Attempts to allocate @n_structs elements of type @struct_type, initialized
370 * to 0's, and returns %NULL on failure. Contrast with g_new0(), which aborts
371 * the program on failure.
372 * The returned pointer is cast to a pointer to the given type.
373 * The function returns %NULL when @n_structs is 0 or if an overflow occurs.
374 *
375 * Since: 2.8
376 * Returns: a pointer to the allocated memory, cast to a pointer to @struct_type
377 */
378#define g_try_new0(struct_type, n_structs) _G_NEW (struct_type, n_structs, try_malloc0)
379/**
380 * g_try_renew:
381 * @struct_type: the type of the elements to allocate
382 * @mem: the currently allocated memory
383 * @n_structs: the number of elements to allocate
384 *
385 * Attempts to reallocate the memory pointed to by @mem, so that it now has
386 * space for @n_structs elements of type @struct_type, and returns %NULL on
387 * failure. Contrast with g_renew(), which aborts the program on failure.
388 * It returns the new address of the memory, which may have been moved.
389 * The function returns %NULL if an overflow occurs.
390 *
391 * Since: 2.8
392 * Returns: a pointer to the new allocated memory, cast to a pointer to @struct_type
393 */
394#define g_try_renew(struct_type, mem, n_structs) _G_RENEW (struct_type, mem, n_structs, try_realloc)
395
396
397/* Memory allocation virtualization for debugging purposes
398 * g_mem_set_vtable() has to be the very first GLib function called
399 * if being used
400 */
401struct _GMemVTable {
402 gpointer (*malloc) (gsize n_bytes);
403 gpointer (*realloc) (gpointer mem,
404 gsize n_bytes);
405 void (*free) (gpointer mem);
406 /* optional; set to NULL if not used ! */
407 gpointer (*calloc) (gsize n_blocks,
408 gsize n_block_bytes);
409 gpointer (*try_malloc) (gsize n_bytes);
410 gpointer (*try_realloc) (gpointer mem,
411 gsize n_bytes);
412};
413GLIB_DEPRECATED_IN_2_46
414void g_mem_set_vtable (GMemVTable *vtable);
415GLIB_DEPRECATED_IN_2_46
416gboolean g_mem_is_system_malloc (void);
417
418GLIB_VAR gboolean g_mem_gc_friendly;
419
420/* Memory profiler and checker, has to be enabled via g_mem_set_vtable()
421 */
422GLIB_VAR GMemVTable *glib_mem_profiler_table;
423GLIB_DEPRECATED_IN_2_46
424void g_mem_profile (void);
425
426G_END_DECLS
427
428#endif /* __G_MEM_H__ */
429