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
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#if defined(g_has_typeof) && GLIB_VERSION_MAX_ALLOWED >= GLIB_VERSION_2_58
114#define g_clear_pointer(pp, destroy) \
115 G_STMT_START { \
116 G_STATIC_ASSERT (sizeof *(pp) == sizeof (gpointer)); \
117 __typeof__((pp)) _pp = (pp); \
118 __typeof__(*(pp)) _ptr = *_pp; \
119 *_pp = NULL; \
120 if (_ptr) \
121 (destroy) (_ptr); \
122 } G_STMT_END
123#else /* __GNUC__ */
124#define g_clear_pointer(pp, destroy) \
125 G_STMT_START { \
126 G_STATIC_ASSERT (sizeof *(pp) == sizeof (gpointer)); \
127 /* Only one access, please; work around type aliasing */ \
128 union { char *in; gpointer *out; } _pp; \
129 gpointer _p; \
130 /* This assignment is needed to avoid a gcc warning */ \
131 GDestroyNotify _destroy = (GDestroyNotify) (destroy); \
132 \
133 _pp.in = (char *) (pp); \
134 _p = *_pp.out; \
135 if (_p) \
136 { \
137 *_pp.out = NULL; \
138 _destroy (_p); \
139 } \
140 } G_STMT_END
141#endif /* __GNUC__ */
142
143/**
144 * g_steal_pointer:
145 * @pp: (not nullable): a pointer to a pointer
146 *
147 * Sets @pp to %NULL, returning the value that was there before.
148 *
149 * Conceptually, this transfers the ownership of the pointer from the
150 * referenced variable to the "caller" of the macro (ie: "steals" the
151 * reference).
152 *
153 * The return value will be properly typed, according to the type of
154 * @pp.
155 *
156 * This can be very useful when combined with g_autoptr() to prevent the
157 * return value of a function from being automatically freed. Consider
158 * the following example (which only works on GCC and clang):
159 *
160 * |[
161 * GObject *
162 * create_object (void)
163 * {
164 * g_autoptr(GObject) obj = g_object_new (G_TYPE_OBJECT, NULL);
165 *
166 * if (early_error_case)
167 * return NULL;
168 *
169 * return g_steal_pointer (&obj);
170 * }
171 * ]|
172 *
173 * It can also be used in similar ways for 'out' parameters and is
174 * particularly useful for dealing with optional out parameters:
175 *
176 * |[
177 * gboolean
178 * get_object (GObject **obj_out)
179 * {
180 * g_autoptr(GObject) obj = g_object_new (G_TYPE_OBJECT, NULL);
181 *
182 * if (early_error_case)
183 * return FALSE;
184 *
185 * if (obj_out)
186 * *obj_out = g_steal_pointer (&obj);
187 *
188 * return TRUE;
189 * }
190 * ]|
191 *
192 * In the above example, the object will be automatically freed in the
193 * early error case and also in the case that %NULL was given for
194 * @obj_out.
195 *
196 * Since: 2.44
197 */
198static inline gpointer
199g_steal_pointer (gpointer pp)
200{
201 gpointer *ptr = (gpointer *) pp;
202 gpointer ref;
203
204 ref = *ptr;
205 *ptr = NULL;
206
207 return ref;
208}
209
210/* type safety */
211#if defined(__GNUC__) && (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 8)) && !defined(__cplusplus) && GLIB_VERSION_MAX_ALLOWED >= GLIB_VERSION_2_58
212#define g_steal_pointer(pp) ((__typeof__(*pp)) (g_steal_pointer) (pp))
213#else /* __GNUC__ */
214/* This version does not depend on gcc extensions, but gcc does not warn
215 * about incompatible-pointer-types: */
216#define g_steal_pointer(pp) \
217 (0 ? (*(pp)) : (g_steal_pointer) (pp))
218#endif /* __GNUC__ */
219
220/* Optimise: avoid the call to the (slower) _n function if we can
221 * determine at compile-time that no overflow happens.
222 */
223#if defined (__GNUC__) && (__GNUC__ >= 2) && defined (__OPTIMIZE__)
224# define _G_NEW(struct_type, n_structs, func) \
225 (struct_type *) (G_GNUC_EXTENSION ({ \
226 gsize __n = (gsize) (n_structs); \
227 gsize __s = sizeof (struct_type); \
228 gpointer __p; \
229 if (__s == 1) \
230 __p = g_##func (__n); \
231 else if (__builtin_constant_p (__n) && \
232 (__s == 0 || __n <= G_MAXSIZE / __s)) \
233 __p = g_##func (__n * __s); \
234 else \
235 __p = g_##func##_n (__n, __s); \
236 __p; \
237 }))
238# define _G_RENEW(struct_type, mem, n_structs, func) \
239 (struct_type *) (G_GNUC_EXTENSION ({ \
240 gsize __n = (gsize) (n_structs); \
241 gsize __s = sizeof (struct_type); \
242 gpointer __p = (gpointer) (mem); \
243 if (__s == 1) \
244 __p = g_##func (__p, __n); \
245 else if (__builtin_constant_p (__n) && \
246 (__s == 0 || __n <= G_MAXSIZE / __s)) \
247 __p = g_##func (__p, __n * __s); \
248 else \
249 __p = g_##func##_n (__p, __n, __s); \
250 __p; \
251 }))
252
253#else
254
255/* Unoptimised version: always call the _n() function. */
256
257#define _G_NEW(struct_type, n_structs, func) \
258 ((struct_type *) g_##func##_n ((n_structs), sizeof (struct_type)))
259#define _G_RENEW(struct_type, mem, n_structs, func) \
260 ((struct_type *) g_##func##_n (mem, (n_structs), sizeof (struct_type)))
261
262#endif
263
264/**
265 * g_new:
266 * @struct_type: the type of the elements to allocate
267 * @n_structs: the number of elements to allocate
268 *
269 * Allocates @n_structs elements of type @struct_type.
270 * The returned pointer is cast to a pointer to the given type.
271 * If @n_structs is 0 it returns %NULL.
272 * Care is taken to avoid overflow when calculating the size of the allocated block.
273 *
274 * Since the returned pointer is already casted to the right type,
275 * it is normally unnecessary to cast it explicitly, and doing
276 * so might hide memory allocation errors.
277 *
278 * Returns: a pointer to the allocated memory, cast to a pointer to @struct_type
279 */
280#define g_new(struct_type, n_structs) _G_NEW (struct_type, n_structs, malloc)
281/**
282 * g_new0:
283 * @struct_type: the type of the elements to allocate.
284 * @n_structs: the number of elements to allocate.
285 *
286 * Allocates @n_structs elements of type @struct_type, initialized to 0's.
287 * The returned pointer is cast to a pointer to the given type.
288 * If @n_structs is 0 it returns %NULL.
289 * Care is taken to avoid overflow when calculating the size of the allocated block.
290 *
291 * Since the returned pointer is already casted to the right type,
292 * it is normally unnecessary to cast it explicitly, and doing
293 * so might hide memory allocation errors.
294 *
295 * Returns: a pointer to the allocated memory, cast to a pointer to @struct_type.
296 */
297#define g_new0(struct_type, n_structs) _G_NEW (struct_type, n_structs, malloc0)
298/**
299 * g_renew:
300 * @struct_type: the type of the elements to allocate
301 * @mem: the currently allocated memory
302 * @n_structs: the number of elements to allocate
303 *
304 * Reallocates the memory pointed to by @mem, so that it now has space for
305 * @n_structs elements of type @struct_type. It returns the new address of
306 * the memory, which may have been moved.
307 * Care is taken to avoid overflow when calculating the size of the allocated block.
308 *
309 * Returns: a pointer to the new allocated memory, cast to a pointer to @struct_type
310 */
311#define g_renew(struct_type, mem, n_structs) _G_RENEW (struct_type, mem, n_structs, realloc)
312/**
313 * g_try_new:
314 * @struct_type: the type of the elements to allocate
315 * @n_structs: the number of elements to allocate
316 *
317 * Attempts to allocate @n_structs elements of type @struct_type, and returns
318 * %NULL on failure. Contrast with g_new(), which aborts the program on failure.
319 * The returned pointer is cast to a pointer to the given type.
320 * The function returns %NULL when @n_structs is 0 of if an overflow occurs.
321 *
322 * Since: 2.8
323 * Returns: a pointer to the allocated memory, cast to a pointer to @struct_type
324 */
325#define g_try_new(struct_type, n_structs) _G_NEW (struct_type, n_structs, try_malloc)
326/**
327 * g_try_new0:
328 * @struct_type: the type of the elements to allocate
329 * @n_structs: the number of elements to allocate
330 *
331 * Attempts to allocate @n_structs elements of type @struct_type, initialized
332 * to 0's, and returns %NULL on failure. Contrast with g_new0(), which aborts
333 * the program on failure.
334 * The returned pointer is cast to a pointer to the given type.
335 * The function returns %NULL when @n_structs is 0 or if an overflow occurs.
336 *
337 * Since: 2.8
338 * Returns: a pointer to the allocated memory, cast to a pointer to @struct_type
339 */
340#define g_try_new0(struct_type, n_structs) _G_NEW (struct_type, n_structs, try_malloc0)
341/**
342 * g_try_renew:
343 * @struct_type: the type of the elements to allocate
344 * @mem: the currently allocated memory
345 * @n_structs: the number of elements to allocate
346 *
347 * Attempts to reallocate the memory pointed to by @mem, so that it now has
348 * space for @n_structs elements of type @struct_type, and returns %NULL on
349 * failure. Contrast with g_renew(), which aborts the program on failure.
350 * It returns the new address of the memory, which may have been moved.
351 * The function returns %NULL if an overflow occurs.
352 *
353 * Since: 2.8
354 * Returns: a pointer to the new allocated memory, cast to a pointer to @struct_type
355 */
356#define g_try_renew(struct_type, mem, n_structs) _G_RENEW (struct_type, mem, n_structs, try_realloc)
357
358
359/* Memory allocation virtualization for debugging purposes
360 * g_mem_set_vtable() has to be the very first GLib function called
361 * if being used
362 */
363struct _GMemVTable {
364 gpointer (*malloc) (gsize n_bytes);
365 gpointer (*realloc) (gpointer mem,
366 gsize n_bytes);
367 void (*free) (gpointer mem);
368 /* optional; set to NULL if not used ! */
369 gpointer (*calloc) (gsize n_blocks,
370 gsize n_block_bytes);
371 gpointer (*try_malloc) (gsize n_bytes);
372 gpointer (*try_realloc) (gpointer mem,
373 gsize n_bytes);
374};
375GLIB_DEPRECATED_IN_2_46
376void g_mem_set_vtable (GMemVTable *vtable);
377GLIB_DEPRECATED_IN_2_46
378gboolean g_mem_is_system_malloc (void);
379
380GLIB_VAR gboolean g_mem_gc_friendly;
381
382/* Memory profiler and checker, has to be enabled via g_mem_set_vtable()
383 */
384GLIB_VAR GMemVTable *glib_mem_profiler_table;
385GLIB_DEPRECATED_IN_2_46
386void g_mem_profile (void);
387
388G_END_DECLS
389
390#endif /* __G_MEM_H__ */
391