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