1 /* GStreamer
2 * Copyright (C) 2011 Wim Taymans <wim.taymans@gmail.be>
3 *
4 * gstallocator.c: memory block allocator
5 *
6 * This library is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Library General Public
8 * License as published by the Free Software Foundation; either
9 * version 2 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 * Library General Public License for more details.
15 *
16 * You should have received a copy of the GNU Library General Public
17 * License along with this library; if not, write to the
18 * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
19 * Boston, MA 02110-1301, USA.
20 */
21
22 /**
23 * SECTION:gstallocator
24 * @title: GstAllocator
25 * @short_description: allocate memory blocks
26 * @see_also: #GstMemory
27 * @auto-sort: false
28 * @symbols:
29 * - GstAllocator
30 *
31 * Memory is usually created by allocators with a gst_allocator_alloc()
32 * method call. When %NULL is used as the allocator, the default allocator will
33 * be used.
34 *
35 * New allocators can be registered with gst_allocator_register().
36 * Allocators are identified by name and can be retrieved with
37 * gst_allocator_find(). gst_allocator_set_default() can be used to change the
38 * default allocator.
39 *
40 * New memory can be created with gst_memory_new_wrapped() that wraps the memory
41 * allocated elsewhere.
42 */
43
44 #ifdef HAVE_CONFIG_H
45 #include "config.h"
46 #endif
47
48 #include "gst_private.h"
49 #include "gstmemory.h"
50
51 GST_DEBUG_CATEGORY_STATIC (gst_allocator_debug);
52 #define GST_CAT_DEFAULT gst_allocator_debug
53
54 struct _GstAllocatorPrivate
55 {
56 gpointer dummy;
57 };
58
59 #if defined(MEMORY_ALIGNMENT_MALLOC)
60 gsize gst_memory_alignment = 7;
61 #elif defined(MEMORY_ALIGNMENT_PAGESIZE)
62 /* we fill this in in the _init method */
63 gsize gst_memory_alignment = 0;
64 #elif defined(MEMORY_ALIGNMENT)
65 gsize gst_memory_alignment = MEMORY_ALIGNMENT - 1;
66 #else
67 #error "No memory alignment configured"
68 gsize gst_memory_alignment = 0;
69 #endif
70
71 /* the default allocator */
72 static GstAllocator *_default_allocator;
73
74 static GstAllocator *_sysmem_allocator;
75
76 /* registered allocators */
77 static GRWLock lock;
78 static GHashTable *allocators;
79
80 G_DEFINE_ABSTRACT_TYPE_WITH_PRIVATE (GstAllocator, gst_allocator,
81 GST_TYPE_OBJECT);
82
83 static void
gst_allocator_class_init(GstAllocatorClass * klass)84 gst_allocator_class_init (GstAllocatorClass * klass)
85 {
86 GST_DEBUG_CATEGORY_INIT (gst_allocator_debug, "allocator", 0,
87 "allocator debug");
88 }
89
90 static GstMemory *
_fallback_mem_copy(GstMemory * mem,gssize offset,gssize size)91 _fallback_mem_copy (GstMemory * mem, gssize offset, gssize size)
92 {
93 GstMemory *copy;
94 GstMapInfo sinfo, dinfo;
95 GstAllocationParams params = { 0, mem->align, 0, 0, };
96 GstAllocator *allocator;
97
98 if (!gst_memory_map (mem, &sinfo, GST_MAP_READ))
99 return NULL;
100
101 if (size == -1)
102 size = sinfo.size > offset ? sinfo.size - offset : 0;
103
104 /* use the same allocator as the memory we copy */
105 allocator = mem->allocator;
106 if (GST_OBJECT_FLAG_IS_SET (allocator, GST_ALLOCATOR_FLAG_CUSTOM_ALLOC))
107 allocator = NULL;
108 copy = gst_allocator_alloc (allocator, size, ¶ms);
109
110 if (!gst_memory_map (copy, &dinfo, GST_MAP_WRITE)) {
111 GST_CAT_WARNING (GST_CAT_MEMORY, "could not write map memory %p", copy);
112 gst_allocator_free (mem->allocator, copy);
113 gst_memory_unmap (mem, &sinfo);
114 return NULL;
115 }
116
117 GST_CAT_DEBUG (GST_CAT_PERFORMANCE,
118 "memcpy %" G_GSSIZE_FORMAT " memory %p -> %p", size, mem, copy);
119 memcpy (dinfo.data, sinfo.data + offset, size);
120 gst_memory_unmap (copy, &dinfo);
121 gst_memory_unmap (mem, &sinfo);
122
123 return copy;
124 }
125
126 static gboolean
_fallback_mem_is_span(GstMemory * mem1,GstMemory * mem2,gsize * offset)127 _fallback_mem_is_span (GstMemory * mem1, GstMemory * mem2, gsize * offset)
128 {
129 return FALSE;
130 }
131
132 static void
gst_allocator_init(GstAllocator * allocator)133 gst_allocator_init (GstAllocator * allocator)
134 {
135 allocator->priv = gst_allocator_get_instance_private (allocator);
136
137 allocator->mem_copy = _fallback_mem_copy;
138 allocator->mem_is_span = _fallback_mem_is_span;
139 }
140
141 G_DEFINE_BOXED_TYPE (GstAllocationParams, gst_allocation_params,
142 (GBoxedCopyFunc) gst_allocation_params_copy,
143 (GBoxedFreeFunc) gst_allocation_params_free);
144
145 /**
146 * gst_allocation_params_new:
147 *
148 * Create a new #GstAllocationParams on the heap. This function is for
149 * use in GStreamer language bindings. In your own code, you can just
150 * declare a #GstAllocationParams on the stack or in a struct, and
151 * call gst_allocation_params_init() to initialize it.
152 *
153 * You do not need to call gst_allocation_params_init() on the instance
154 * returned by this function.
155 *
156 * Returns: (transfer full) (not nullable): a new #GstAllocationParams
157 *
158 * Since: 1.20
159 */
160 GstAllocationParams *
gst_allocation_params_new(void)161 gst_allocation_params_new (void)
162 {
163 /* Call new() and then init(), rather than calling new0(), in case
164 * init() ever changes to something other than a memset(). */
165 GstAllocationParams *result = g_slice_new (GstAllocationParams);
166 gst_allocation_params_init (result);
167 return result;
168 }
169
170 /**
171 * gst_allocation_params_init:
172 * @params: a #GstAllocationParams
173 *
174 * Initialize @params to its default values
175 */
176 void
gst_allocation_params_init(GstAllocationParams * params)177 gst_allocation_params_init (GstAllocationParams * params)
178 {
179 g_return_if_fail (params != NULL);
180
181 memset (params, 0, sizeof (GstAllocationParams));
182 }
183
184 /**
185 * gst_allocation_params_copy:
186 * @params: (transfer none) (nullable): a #GstAllocationParams
187 *
188 * Create a copy of @params.
189 *
190 * Returns: (transfer full) (nullable): a new #GstAllocationParams.
191 */
192 GstAllocationParams *
gst_allocation_params_copy(const GstAllocationParams * params)193 gst_allocation_params_copy (const GstAllocationParams * params)
194 {
195 GstAllocationParams *result = NULL;
196
197 if (params) {
198 result =
199 (GstAllocationParams *) g_slice_copy (sizeof (GstAllocationParams),
200 params);
201 }
202 return result;
203 }
204
205 /**
206 * gst_allocation_params_free:
207 * @params: (in) (transfer full): a #GstAllocationParams
208 *
209 * Free @params
210 */
211 void
gst_allocation_params_free(GstAllocationParams * params)212 gst_allocation_params_free (GstAllocationParams * params)
213 {
214 g_slice_free (GstAllocationParams, params);
215 }
216
217 /**
218 * gst_allocator_register:
219 * @name: the name of the allocator
220 * @allocator: (transfer full): #GstAllocator
221 *
222 * Registers the memory @allocator with @name.
223 */
224 void
gst_allocator_register(const gchar * name,GstAllocator * allocator)225 gst_allocator_register (const gchar * name, GstAllocator * allocator)
226 {
227 g_return_if_fail (name != NULL);
228 g_return_if_fail (allocator != NULL);
229
230 GST_CAT_DEBUG (GST_CAT_MEMORY, "registering allocator %p with name \"%s\"",
231 allocator, name);
232
233 g_rw_lock_writer_lock (&lock);
234 /* The ref will never be released */
235 GST_OBJECT_FLAG_SET (allocator, GST_OBJECT_FLAG_MAY_BE_LEAKED);
236 g_hash_table_insert (allocators, (gpointer) name, (gpointer) allocator);
237 g_rw_lock_writer_unlock (&lock);
238 }
239
240 /**
241 * gst_allocator_find:
242 * @name: (allow-none): the name of the allocator
243 *
244 * Find a previously registered allocator with @name. When @name is %NULL, the
245 * default allocator will be returned.
246 *
247 * Returns: (transfer full) (nullable): a #GstAllocator or %NULL when
248 * the allocator with @name was not registered.
249 */
250 GstAllocator *
gst_allocator_find(const gchar * name)251 gst_allocator_find (const gchar * name)
252 {
253 GstAllocator *allocator;
254
255 g_rw_lock_reader_lock (&lock);
256 if (name) {
257 allocator = g_hash_table_lookup (allocators, (gconstpointer) name);
258 } else {
259 allocator = _default_allocator;
260 }
261 if (allocator)
262 gst_object_ref (allocator);
263 g_rw_lock_reader_unlock (&lock);
264
265 return allocator;
266 }
267
268 /**
269 * gst_allocator_set_default:
270 * @allocator: (transfer full): a #GstAllocator
271 *
272 * Set the default allocator.
273 */
274 void
gst_allocator_set_default(GstAllocator * allocator)275 gst_allocator_set_default (GstAllocator * allocator)
276 {
277 GstAllocator *old;
278
279 g_return_if_fail (GST_IS_ALLOCATOR (allocator));
280
281 g_rw_lock_writer_lock (&lock);
282 old = _default_allocator;
283 _default_allocator = allocator;
284 g_rw_lock_writer_unlock (&lock);
285
286 if (old)
287 gst_object_unref (old);
288 }
289
290 /**
291 * gst_allocator_alloc:
292 * @allocator: (transfer none) (allow-none): a #GstAllocator to use
293 * @size: size of the visible memory area
294 * @params: (transfer none) (allow-none): optional parameters
295 *
296 * Use @allocator to allocate a new memory block with memory that is at least
297 * @size big.
298 *
299 * The optional @params can specify the prefix and padding for the memory. If
300 * %NULL is passed, no flags, no extra prefix/padding and a default alignment is
301 * used.
302 *
303 * The prefix/padding will be filled with 0 if flags contains
304 * #GST_MEMORY_FLAG_ZERO_PREFIXED and #GST_MEMORY_FLAG_ZERO_PADDED respectively.
305 *
306 * When @allocator is %NULL, the default allocator will be used.
307 *
308 * The alignment in @params is given as a bitmask so that @align + 1 equals
309 * the amount of bytes to align to. For example, to align to 8 bytes,
310 * use an alignment of 7.
311 *
312 * Returns: (transfer full) (nullable): a new #GstMemory.
313 */
314 GstMemory *
gst_allocator_alloc(GstAllocator * allocator,gsize size,GstAllocationParams * params)315 gst_allocator_alloc (GstAllocator * allocator, gsize size,
316 GstAllocationParams * params)
317 {
318 GstMemory *mem;
319 static GstAllocationParams defparams = { 0, 0, 0, 0, };
320 GstAllocatorClass *aclass;
321
322 if (params) {
323 g_return_val_if_fail (((params->align + 1) & params->align) == 0, NULL);
324 } else {
325 params = &defparams;
326 }
327
328 if (allocator == NULL)
329 allocator = _default_allocator;
330
331 aclass = GST_ALLOCATOR_GET_CLASS (allocator);
332 if (aclass->alloc)
333 mem = aclass->alloc (allocator, size, params);
334 else
335 mem = NULL;
336
337 return mem;
338 }
339
340 /**
341 * gst_allocator_free:
342 * @allocator: (transfer none): a #GstAllocator to use
343 * @memory: (transfer full): the memory to free
344 *
345 * Free @memory that was previously allocated with gst_allocator_alloc().
346 */
347 void
gst_allocator_free(GstAllocator * allocator,GstMemory * memory)348 gst_allocator_free (GstAllocator * allocator, GstMemory * memory)
349 {
350 GstAllocatorClass *aclass;
351
352 g_return_if_fail (GST_IS_ALLOCATOR (allocator));
353 g_return_if_fail (memory != NULL);
354 g_return_if_fail (memory->allocator == allocator);
355
356 aclass = GST_ALLOCATOR_GET_CLASS (allocator);
357 if (aclass->free)
358 aclass->free (allocator, memory);
359 }
360
361 /* default memory implementation */
362 typedef struct
363 {
364 GstMemory mem;
365
366 gsize slice_size;
367 guint8 *data;
368
369 gpointer user_data;
370 GDestroyNotify notify;
371 } GstMemorySystem;
372
373 typedef struct
374 {
375 GstAllocator parent;
376 } GstAllocatorSysmem;
377
378 typedef struct
379 {
380 GstAllocatorClass parent_class;
381 } GstAllocatorSysmemClass;
382
383 static GType gst_allocator_sysmem_get_type (void);
384 G_DEFINE_TYPE (GstAllocatorSysmem, gst_allocator_sysmem, GST_TYPE_ALLOCATOR);
385
386 /* initialize the fields */
387 static inline void
_sysmem_init(GstMemorySystem * mem,GstMemoryFlags flags,GstMemory * parent,gsize slice_size,gpointer data,gsize maxsize,gsize align,gsize offset,gsize size,gpointer user_data,GDestroyNotify notify)388 _sysmem_init (GstMemorySystem * mem, GstMemoryFlags flags,
389 GstMemory * parent, gsize slice_size,
390 gpointer data, gsize maxsize, gsize align, gsize offset, gsize size,
391 gpointer user_data, GDestroyNotify notify)
392 {
393 gst_memory_init (GST_MEMORY_CAST (mem),
394 flags, _sysmem_allocator, parent, maxsize, align, offset, size);
395
396 mem->slice_size = slice_size;
397 mem->data = data;
398 mem->user_data = user_data;
399 mem->notify = notify;
400 }
401
402 /* create a new memory block that manages the given memory */
403 static inline GstMemorySystem *
_sysmem_new(GstMemoryFlags flags,GstMemory * parent,gpointer data,gsize maxsize,gsize align,gsize offset,gsize size,gpointer user_data,GDestroyNotify notify)404 _sysmem_new (GstMemoryFlags flags,
405 GstMemory * parent, gpointer data, gsize maxsize, gsize align, gsize offset,
406 gsize size, gpointer user_data, GDestroyNotify notify)
407 {
408 GstMemorySystem *mem;
409 gsize slice_size;
410
411 slice_size = sizeof (GstMemorySystem);
412
413 mem = g_slice_alloc (slice_size);
414 _sysmem_init (mem, flags, parent, slice_size,
415 data, maxsize, align, offset, size, user_data, notify);
416
417 return mem;
418 }
419
420 /* allocate the memory and structure in one block */
421 static GstMemorySystem *
_sysmem_new_block(GstMemoryFlags flags,gsize maxsize,gsize align,gsize offset,gsize size)422 _sysmem_new_block (GstMemoryFlags flags,
423 gsize maxsize, gsize align, gsize offset, gsize size)
424 {
425 GstMemorySystem *mem;
426 gsize aoffset, slice_size, padding;
427 guint8 *data;
428
429 /* ensure configured alignment */
430 align |= gst_memory_alignment;
431 /* allocate more to compensate for alignment */
432 maxsize += align;
433 /* alloc header and data in one block */
434 slice_size = sizeof (GstMemorySystem) + maxsize;
435
436 mem = g_slice_alloc (slice_size);
437 if (mem == NULL)
438 return NULL;
439
440 data = (guint8 *) mem + sizeof (GstMemorySystem);
441
442 /* do alignment */
443 if ((aoffset = ((guintptr) data & align))) {
444 aoffset = (align + 1) - aoffset;
445 data += aoffset;
446 maxsize -= aoffset;
447 }
448
449 if (offset && (flags & GST_MEMORY_FLAG_ZERO_PREFIXED))
450 memset (data, 0, offset);
451
452 padding = maxsize - (offset + size);
453 if (padding && (flags & GST_MEMORY_FLAG_ZERO_PADDED))
454 memset (data + offset + size, 0, padding);
455
456 _sysmem_init (mem, flags, NULL, slice_size, data, maxsize,
457 align, offset, size, NULL, NULL);
458
459 return mem;
460 }
461
462 static gpointer
_sysmem_map(GstMemorySystem * mem,gsize maxsize,GstMapFlags flags)463 _sysmem_map (GstMemorySystem * mem, gsize maxsize, GstMapFlags flags)
464 {
465 return mem->data;
466 }
467
468 static gboolean
_sysmem_unmap(GstMemorySystem * mem)469 _sysmem_unmap (GstMemorySystem * mem)
470 {
471 return TRUE;
472 }
473
474 static GstMemorySystem *
_sysmem_copy(GstMemorySystem * mem,gssize offset,gsize size)475 _sysmem_copy (GstMemorySystem * mem, gssize offset, gsize size)
476 {
477 GstMemorySystem *copy;
478
479 if (size == -1)
480 size = mem->mem.size > offset ? mem->mem.size - offset : 0;
481
482 copy = _sysmem_new_block (0, size, mem->mem.align, 0, size);
483 GST_CAT_DEBUG (GST_CAT_PERFORMANCE,
484 "memcpy %" G_GSIZE_FORMAT " memory %p -> %p", size, mem, copy);
485 memcpy (copy->data, mem->data + mem->mem.offset + offset, size);
486
487 return copy;
488 }
489
490 static GstMemorySystem *
_sysmem_share(GstMemorySystem * mem,gssize offset,gsize size)491 _sysmem_share (GstMemorySystem * mem, gssize offset, gsize size)
492 {
493 GstMemorySystem *sub;
494 GstMemory *parent;
495
496 /* find the real parent */
497 if ((parent = mem->mem.parent) == NULL)
498 parent = (GstMemory *) mem;
499
500 if (size == -1)
501 size = mem->mem.size - offset;
502
503 /* the shared memory is always readonly */
504 sub =
505 _sysmem_new (GST_MINI_OBJECT_FLAGS (parent) |
506 GST_MINI_OBJECT_FLAG_LOCK_READONLY, parent, mem->data, mem->mem.maxsize,
507 mem->mem.align, mem->mem.offset + offset, size, NULL, NULL);
508
509 return sub;
510 }
511
512 static gboolean
_sysmem_is_span(GstMemorySystem * mem1,GstMemorySystem * mem2,gsize * offset)513 _sysmem_is_span (GstMemorySystem * mem1, GstMemorySystem * mem2, gsize * offset)
514 {
515
516 if (offset) {
517 GstMemorySystem *parent;
518
519 parent = (GstMemorySystem *) mem1->mem.parent;
520
521 *offset = mem1->mem.offset - parent->mem.offset;
522 }
523
524 /* and memory is contiguous */
525 return mem1->data + mem1->mem.offset + mem1->mem.size ==
526 mem2->data + mem2->mem.offset;
527 }
528
529 static GstMemory *
default_alloc(GstAllocator * allocator,gsize size,GstAllocationParams * params)530 default_alloc (GstAllocator * allocator, gsize size,
531 GstAllocationParams * params)
532 {
533 gsize maxsize = size + params->prefix + params->padding;
534
535 return (GstMemory *) _sysmem_new_block (params->flags,
536 maxsize, params->align, params->prefix, size);
537 }
538
539 static void
default_free(GstAllocator * allocator,GstMemory * mem)540 default_free (GstAllocator * allocator, GstMemory * mem)
541 {
542 GstMemorySystem *dmem = (GstMemorySystem *) mem;
543 gsize slice_size;
544
545 if (dmem->notify)
546 dmem->notify (dmem->user_data);
547
548 slice_size = dmem->slice_size;
549
550 #ifdef USE_POISONING
551 /* just poison the structs, not all the data */
552 memset (mem, 0xff, sizeof (GstMemorySystem));
553 #endif
554
555 g_slice_free1 (slice_size, mem);
556 }
557
558 static void
gst_allocator_sysmem_finalize(GObject * obj)559 gst_allocator_sysmem_finalize (GObject * obj)
560 {
561 /* Don't raise warnings if we are shutting down */
562 if (_default_allocator)
563 g_warning ("The default memory allocator was freed!");
564
565 ((GObjectClass *) gst_allocator_sysmem_parent_class)->finalize (obj);
566 }
567
568 static void
gst_allocator_sysmem_class_init(GstAllocatorSysmemClass * klass)569 gst_allocator_sysmem_class_init (GstAllocatorSysmemClass * klass)
570 {
571 GObjectClass *gobject_class;
572 GstAllocatorClass *allocator_class;
573
574 gobject_class = (GObjectClass *) klass;
575 allocator_class = (GstAllocatorClass *) klass;
576
577 gobject_class->finalize = gst_allocator_sysmem_finalize;
578
579 allocator_class->alloc = default_alloc;
580 allocator_class->free = default_free;
581 }
582
583 static void
gst_allocator_sysmem_init(GstAllocatorSysmem * allocator)584 gst_allocator_sysmem_init (GstAllocatorSysmem * allocator)
585 {
586 GstAllocator *alloc = GST_ALLOCATOR_CAST (allocator);
587
588 GST_CAT_DEBUG (GST_CAT_MEMORY, "init allocator %p", allocator);
589
590 alloc->mem_type = GST_ALLOCATOR_SYSMEM;
591 alloc->mem_map = (GstMemoryMapFunction) _sysmem_map;
592 alloc->mem_unmap = (GstMemoryUnmapFunction) _sysmem_unmap;
593 alloc->mem_copy = (GstMemoryCopyFunction) _sysmem_copy;
594 alloc->mem_share = (GstMemoryShareFunction) _sysmem_share;
595 alloc->mem_is_span = (GstMemoryIsSpanFunction) _sysmem_is_span;
596 }
597
598 void
_priv_gst_allocator_initialize(void)599 _priv_gst_allocator_initialize (void)
600 {
601 g_rw_lock_init (&lock);
602 allocators = g_hash_table_new_full (g_str_hash, g_str_equal, NULL,
603 gst_object_unref);
604
605 #ifdef HAVE_GETPAGESIZE
606 #ifdef MEMORY_ALIGNMENT_PAGESIZE
607 gst_memory_alignment = getpagesize () - 1;
608 #endif
609 #endif
610
611 GST_CAT_DEBUG (GST_CAT_MEMORY, "memory alignment: %" G_GSIZE_FORMAT,
612 gst_memory_alignment);
613
614 _sysmem_allocator = g_object_new (gst_allocator_sysmem_get_type (), NULL);
615
616 /* Clear floating flag */
617 gst_object_ref_sink (_sysmem_allocator);
618
619 gst_allocator_register (GST_ALLOCATOR_SYSMEM,
620 gst_object_ref (_sysmem_allocator));
621
622 _default_allocator = gst_object_ref (_sysmem_allocator);
623 }
624
625 void
_priv_gst_allocator_cleanup(void)626 _priv_gst_allocator_cleanup (void)
627 {
628 gst_object_unref (_sysmem_allocator);
629 _sysmem_allocator = NULL;
630
631 gst_object_unref (_default_allocator);
632 _default_allocator = NULL;
633
634 g_clear_pointer (&allocators, g_hash_table_unref);
635 }
636
637 /**
638 * gst_memory_new_wrapped:
639 * @flags: #GstMemoryFlags
640 * @data: (array length=size) (element-type guint8) (transfer none): data to
641 * wrap
642 * @maxsize: allocated size of @data
643 * @offset: offset in @data
644 * @size: size of valid data
645 * @user_data: (allow-none): user_data
646 * @notify: (allow-none) (scope async) (closure user_data): called with @user_data when the memory is freed
647 *
648 * Allocate a new memory block that wraps the given @data.
649 *
650 * The prefix/padding must be filled with 0 if @flags contains
651 * #GST_MEMORY_FLAG_ZERO_PREFIXED and #GST_MEMORY_FLAG_ZERO_PADDED respectively.
652 *
653 * Returns: (transfer full) (nullable): a new #GstMemory.
654 */
655 GstMemory *
gst_memory_new_wrapped(GstMemoryFlags flags,gpointer data,gsize maxsize,gsize offset,gsize size,gpointer user_data,GDestroyNotify notify)656 gst_memory_new_wrapped (GstMemoryFlags flags, gpointer data,
657 gsize maxsize, gsize offset, gsize size, gpointer user_data,
658 GDestroyNotify notify)
659 {
660 GstMemorySystem *mem;
661
662 g_return_val_if_fail (data != NULL, NULL);
663 g_return_val_if_fail (offset + size <= maxsize, NULL);
664
665 mem =
666 _sysmem_new (flags, NULL, data, maxsize, 0, offset, size, user_data,
667 notify);
668
669 return (GstMemory *) mem;
670 }
671