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 GLIB_AVAILABLE_MACRO_IN_2_34
124#else /* __GNUC__ */
125#define g_clear_pointer(pp, destroy) \
126 G_STMT_START { \
127 G_STATIC_ASSERT (sizeof *(pp) == sizeof (gpointer)); \
128 /* Only one access, please; work around type aliasing */ \
129 union { char *in; gpointer *out; } _pp; \
130 gpointer _p; \
131 /* This assignment is needed to avoid a gcc warning */ \
132 GDestroyNotify _destroy = (GDestroyNotify) (destroy); \
133 \
134 _pp.in = (char *) (pp); \
135 _p = *_pp.out; \
136 if (_p) \
137 { \
138 *_pp.out = NULL; \
139 _destroy (_p); \
140 } \
141 } G_STMT_END \
142 GLIB_AVAILABLE_MACRO_IN_2_34
143#endif /* __GNUC__ */
144
145/**
146 * g_steal_pointer:
147 * @pp: (not nullable): a pointer to a pointer
148 *
149 * Sets @pp to %NULL, returning the value that was there before.
150 *
151 * Conceptually, this transfers the ownership of the pointer from the
152 * referenced variable to the "caller" of the macro (ie: "steals" the
153 * reference).
154 *
155 * The return value will be properly typed, according to the type of
156 * @pp.
157 *
158 * This can be very useful when combined with g_autoptr() to prevent the
159 * return value of a function from being automatically freed. Consider
160 * the following example (which only works on GCC and clang):
161 *
162 * |[
163 * GObject *
164 * create_object (void)
165 * {
166 * g_autoptr(GObject) obj = g_object_new (G_TYPE_OBJECT, NULL);
167 *
168 * if (early_error_case)
169 * return NULL;
170 *
171 * return g_steal_pointer (&obj);
172 * }
173 * ]|
174 *
175 * It can also be used in similar ways for 'out' parameters and is
176 * particularly useful for dealing with optional out parameters:
177 *
178 * |[
179 * gboolean
180 * get_object (GObject **obj_out)
181 * {
182 * g_autoptr(GObject) obj = g_object_new (G_TYPE_OBJECT, NULL);
183 *
184 * if (early_error_case)
185 * return FALSE;
186 *
187 * if (obj_out)
188 * *obj_out = g_steal_pointer (&obj);
189 *
190 * return TRUE;
191 * }
192 * ]|
193 *
194 * In the above example, the object will be automatically freed in the
195 * early error case and also in the case that %NULL was given for
196 * @obj_out.
197 *
198 * Since: 2.44
199 */
200static inline gpointer
201g_steal_pointer (gpointer pp)
202{
203 gpointer *ptr = (gpointer *) pp;
204 gpointer ref;
205
206 ref = *ptr;
207 *ptr = NULL;
208
209 return ref;
210}
211
212/* type safety */
213#if defined(__GNUC__) && (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 8)) && !defined(__cplusplus) && GLIB_VERSION_MAX_ALLOWED >= GLIB_VERSION_2_58
214#define g_steal_pointer(pp) ((__typeof__(*pp)) (g_steal_pointer) (pp))
215#else /* __GNUC__ */
216/* This version does not depend on gcc extensions, but gcc does not warn
217 * about incompatible-pointer-types: */
218#define g_steal_pointer(pp) \
219 (0 ? (*(pp)) : (g_steal_pointer) (pp))
220#endif /* __GNUC__ */
221
222/* Optimise: avoid the call to the (slower) _n function if we can
223 * determine at compile-time that no overflow happens.
224 */
225#if defined (__GNUC__) && (__GNUC__ >= 2) && defined (__OPTIMIZE__)
226# define _G_NEW(struct_type, n_structs, func) \
227 (struct_type *) (G_GNUC_EXTENSION ({ \
228 gsize __n = (gsize) (n_structs); \
229 gsize __s = sizeof (struct_type); \
230 gpointer __p; \
231 if (__s == 1) \
232 __p = g_##func (__n); \
233 else if (__builtin_constant_p (__n) && \
234 (__s == 0 || __n <= G_MAXSIZE / __s)) \
235 __p = g_##func (__n * __s); \
236 else \
237 __p = g_##func##_n (__n, __s); \
238 __p; \
239 }))
240# define _G_RENEW(struct_type, mem, n_structs, func) \
241 (struct_type *) (G_GNUC_EXTENSION ({ \
242 gsize __n = (gsize) (n_structs); \
243 gsize __s = sizeof (struct_type); \
244 gpointer __p = (gpointer) (mem); \
245 if (__s == 1) \
246 __p = g_##func (__p, __n); \
247 else if (__builtin_constant_p (__n) && \
248 (__s == 0 || __n <= G_MAXSIZE / __s)) \
249 __p = g_##func (__p, __n * __s); \
250 else \
251 __p = g_##func##_n (__p, __n, __s); \
252 __p; \
253 }))
254
255#else
256
257/* Unoptimised version: always call the _n() function. */
258
259#define _G_NEW(struct_type, n_structs, func) \
260 ((struct_type *) g_##func##_n ((n_structs), sizeof (struct_type)))
261#define _G_RENEW(struct_type, mem, n_structs, func) \
262 ((struct_type *) g_##func##_n (mem, (n_structs), sizeof (struct_type)))
263
264#endif
265
266/**
267 * g_new:
268 * @struct_type: the type of the elements to allocate
269 * @n_structs: the number of elements to allocate
270 *
271 * Allocates @n_structs elements of type @struct_type.
272 * The returned pointer is cast to a pointer to the given type.
273 * If @n_structs is 0 it returns %NULL.
274 * Care is taken to avoid overflow when calculating the size of the allocated block.
275 *
276 * Since the returned pointer is already casted to the right type,
277 * it is normally unnecessary to cast it explicitly, and doing
278 * so might hide memory allocation errors.
279 *
280 * Returns: a pointer to the allocated memory, cast to a pointer to @struct_type
281 */
282#define g_new(struct_type, n_structs) _G_NEW (struct_type, n_structs, malloc)
283/**
284 * g_new0:
285 * @struct_type: the type of the elements to allocate.
286 * @n_structs: the number of elements to allocate.
287 *
288 * Allocates @n_structs elements of type @struct_type, initialized to 0's.
289 * The returned pointer is cast to a pointer to the given type.
290 * If @n_structs is 0 it returns %NULL.
291 * Care is taken to avoid overflow when calculating the size of the allocated block.
292 *
293 * Since the returned pointer is already casted to the right type,
294 * it is normally unnecessary to cast it explicitly, and doing
295 * so might hide memory allocation errors.
296 *
297 * Returns: a pointer to the allocated memory, cast to a pointer to @struct_type.
298 */
299#define g_new0(struct_type, n_structs) _G_NEW (struct_type, n_structs, malloc0)
300/**
301 * g_renew:
302 * @struct_type: the type of the elements to allocate
303 * @mem: the currently allocated memory
304 * @n_structs: the number of elements to allocate
305 *
306 * Reallocates the memory pointed to by @mem, so that it now has space for
307 * @n_structs elements of type @struct_type. It returns the new address of
308 * the memory, which may have been moved.
309 * Care is taken to avoid overflow when calculating the size of the allocated block.
310 *
311 * Returns: a pointer to the new allocated memory, cast to a pointer to @struct_type
312 */
313#define g_renew(struct_type, mem, n_structs) _G_RENEW (struct_type, mem, n_structs, realloc)
314/**
315 * g_try_new:
316 * @struct_type: the type of the elements to allocate
317 * @n_structs: the number of elements to allocate
318 *
319 * Attempts to allocate @n_structs elements of type @struct_type, and returns
320 * %NULL on failure. Contrast with g_new(), which aborts the program on failure.
321 * The returned pointer is cast to a pointer to the given type.
322 * The function returns %NULL when @n_structs is 0 of if an overflow occurs.
323 *
324 * Since: 2.8
325 * Returns: a pointer to the allocated memory, cast to a pointer to @struct_type
326 */
327#define g_try_new(struct_type, n_structs) _G_NEW (struct_type, n_structs, try_malloc)
328/**
329 * g_try_new0:
330 * @struct_type: the type of the elements to allocate
331 * @n_structs: the number of elements to allocate
332 *
333 * Attempts to allocate @n_structs elements of type @struct_type, initialized
334 * to 0's, and returns %NULL on failure. Contrast with g_new0(), which aborts
335 * the program on failure.
336 * The returned pointer is cast to a pointer to the given type.
337 * The function returns %NULL when @n_structs is 0 or if an overflow occurs.
338 *
339 * Since: 2.8
340 * Returns: a pointer to the allocated memory, cast to a pointer to @struct_type
341 */
342#define g_try_new0(struct_type, n_structs) _G_NEW (struct_type, n_structs, try_malloc0)
343/**
344 * g_try_renew:
345 * @struct_type: the type of the elements to allocate
346 * @mem: the currently allocated memory
347 * @n_structs: the number of elements to allocate
348 *
349 * Attempts to reallocate the memory pointed to by @mem, so that it now has
350 * space for @n_structs elements of type @struct_type, and returns %NULL on
351 * failure. Contrast with g_renew(), which aborts the program on failure.
352 * It returns the new address of the memory, which may have been moved.
353 * The function returns %NULL if an overflow occurs.
354 *
355 * Since: 2.8
356 * Returns: a pointer to the new allocated memory, cast to a pointer to @struct_type
357 */
358#define g_try_renew(struct_type, mem, n_structs) _G_RENEW (struct_type, mem, n_structs, try_realloc)
359
360
361/* Memory allocation virtualization for debugging purposes
362 * g_mem_set_vtable() has to be the very first GLib function called
363 * if being used
364 */
365struct _GMemVTable {
366 gpointer (*malloc) (gsize n_bytes);
367 gpointer (*realloc) (gpointer mem,
368 gsize n_bytes);
369 void (*free) (gpointer mem);
370 /* optional; set to NULL if not used ! */
371 gpointer (*calloc) (gsize n_blocks,
372 gsize n_block_bytes);
373 gpointer (*try_malloc) (gsize n_bytes);
374 gpointer (*try_realloc) (gpointer mem,
375 gsize n_bytes);
376};
377GLIB_DEPRECATED_IN_2_46
378void g_mem_set_vtable (GMemVTable *vtable);
379GLIB_DEPRECATED_IN_2_46
380gboolean g_mem_is_system_malloc (void);
381
382GLIB_VAR gboolean g_mem_gc_friendly;
383
384/* Memory profiler and checker, has to be enabled via g_mem_set_vtable()
385 */
386GLIB_VAR GMemVTable *glib_mem_profiler_table;
387GLIB_DEPRECATED_IN_2_46
388void g_mem_profile (void);
389
390G_END_DECLS
391
392#endif /* __G_MEM_H__ */
393