2 * Copyright (C) 2011 Wim Taymans <wim.taymans@gmail.be>
4 * gstmemory.c: memory block handling
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.
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.
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., 59 Temple Place - Suite 330,
19 * Boston, MA 02111-1307, USA.
24 * @short_description: refcounted wrapper for memory blocks
25 * @see_also: #GstBuffer
27 * GstMemory is a lightweight refcounted object that wraps a region of memory.
28 * They are typically used to manage the data of a #GstBuffer.
30 * A GstMemory object has an allocated region of memory of maxsize. The maximum
31 * size does not change during the lifetime of the memory object. The memory
32 * also has an offset and size property that specifies the valid range of memory
33 * in the allocated region.
35 * Memory is usually created by allocators with a gst_allocator_alloc()
36 * method call. When NULL is used as the allocator, the default allocator will
39 * New allocators can be registered with gst_allocator_register().
40 * Allocators are identified by name and can be retrieved with
41 * gst_allocator_find(). gst_allocator_set_default() can be used to change the
44 * New memory can be created with gst_memory_new_wrapped() that wraps the memory
45 * allocated elsewhere.
47 * Refcounting of the memory block is performed with gst_memory_ref() and
50 * The size of the memory can be retrieved and changed with
51 * gst_memory_get_sizes() and gst_memory_resize() respectively.
53 * Getting access to the data of the memory is performed with gst_memory_map().
54 * The call will return a pointer to offset bytes into the region of memory.
55 * After the memory access is completed, gst_memory_unmap() should be called.
57 * Memory can be copied with gst_memory_copy(), which will return a writable
58 * copy. gst_memory_share() will create a new memory block that shares the
59 * memory with an existing memory block at a custom offset and with a custom
62 * Memory can be efficiently merged when gst_memory_is_span() returns TRUE.
64 * Last reviewed on 2012-03-28 (0.11.3)
71 #include "gst_private.h"
72 #include "gstmemory.h"
74 GST_DEFINE_MINI_OBJECT_TYPE (GstMemory, gst_memory);
76 GST_DEFINE_MINI_OBJECT_TYPE (GstAllocator, gst_allocator);
78 G_DEFINE_BOXED_TYPE (GstAllocationParams, gst_allocation_params,
79 (GBoxedCopyFunc) gst_allocation_params_copy,
80 (GBoxedFreeFunc) gst_allocation_params_free);
82 #if defined(MEMORY_ALIGNMENT_MALLOC)
83 size_t gst_memory_alignment = 7;
84 #elif defined(MEMORY_ALIGNMENT_PAGESIZE)
85 /* we fill this in in the _init method */
86 size_t gst_memory_alignment = 0;
87 #elif defined(MEMORY_ALIGNMENT)
88 size_t gst_memory_alignment = MEMORY_ALIGNMENT - 1;
90 #error "No memory alignment configured"
91 size_t gst_memory_alignment = 0;
96 GstMiniObject mini_object;
101 GDestroyNotify notify;
104 /* default memory implementation */
111 GDestroyNotify notify;
114 /* the default allocator */
115 static GstAllocator *_default_allocator;
117 /* our predefined allocators */
118 static GstAllocator *_default_mem_impl;
120 #define SHARE_ONE (1 << 16)
121 #define LOCK_ONE (GST_LOCK_FLAG_LAST)
122 #define FLAG_MASK (GST_LOCK_FLAG_LAST - 1)
123 #define LOCK_MASK ((SHARE_ONE - 1) - FLAG_MASK)
124 #define LOCK_FLAG_MASK (SHARE_ONE - 1)
127 _gst_memory_copy (GstMemory * mem)
129 return gst_memory_copy (mem, 0, -1);
133 _gst_memory_free (GstMemory * mem)
135 /* there should be no outstanding mappings */
136 g_return_if_fail ((g_atomic_int_get (&mem->state) & LOCK_MASK) < 4);
137 mem->allocator->info.mem_free (mem);
140 /* initialize the fields */
142 _default_mem_init (GstMemoryDefault * mem, GstMemoryFlags flags,
143 GstMemory * parent, gsize slice_size, gpointer data,
144 gsize maxsize, gsize offset, gsize size, gsize align,
145 gpointer user_data, GDestroyNotify notify)
147 gst_mini_object_init (GST_MINI_OBJECT_CAST (mem), GST_TYPE_MEMORY,
148 (GstMiniObjectCopyFunction) _gst_memory_copy, NULL,
149 (GstMiniObjectFreeFunction) _gst_memory_free);
151 mem->mem.mini_object.flags = flags;
153 mem->mem.allocator = _default_mem_impl;
154 mem->mem.parent = parent ? gst_memory_ref (parent) : NULL;
155 mem->mem.state = (flags & GST_MEMORY_FLAG_READONLY ? GST_LOCK_FLAG_READ : 0);
156 mem->mem.maxsize = maxsize;
157 mem->mem.align = align;
158 mem->mem.offset = offset;
159 mem->mem.size = size;
160 mem->slice_size = slice_size;
162 mem->user_data = user_data;
163 mem->notify = notify;
165 GST_CAT_DEBUG (GST_CAT_MEMORY, "new memory %p, maxsize:%" G_GSIZE_FORMAT
166 " offset:%" G_GSIZE_FORMAT " size:%" G_GSIZE_FORMAT, mem, maxsize,
170 /* create a new memory block that manages the given memory */
171 static GstMemoryDefault *
172 _default_mem_new (GstMemoryFlags flags, GstMemory * parent, gpointer data,
173 gsize maxsize, gsize offset, gsize size, gsize align, gpointer user_data,
174 GDestroyNotify notify)
176 GstMemoryDefault *mem;
179 slice_size = sizeof (GstMemoryDefault);
181 mem = g_slice_alloc (slice_size);
182 _default_mem_init (mem, flags, parent, slice_size,
183 data, maxsize, offset, size, align, user_data, notify);
188 /* allocate the memory and structure in one block */
189 static GstMemoryDefault *
190 _default_mem_new_block (GstMemoryFlags flags, gsize maxsize, gsize align,
191 gsize offset, gsize size)
193 GstMemoryDefault *mem;
194 gsize aoffset, slice_size, padding;
197 /* ensure configured alignment */
198 align |= gst_memory_alignment;
199 /* allocate more to compensate for alignment */
201 /* alloc header and data in one block */
202 slice_size = sizeof (GstMemoryDefault) + maxsize;
204 mem = g_slice_alloc (slice_size);
208 data = (guint8 *) mem + sizeof (GstMemoryDefault);
211 if ((aoffset = ((guintptr) data & align))) {
212 aoffset = (align + 1) - aoffset;
217 if (offset && (flags & GST_MEMORY_FLAG_ZERO_PREFIXED))
218 memset (data, 0, offset);
220 padding = maxsize - (offset + size);
221 if (padding && (flags & GST_MEMORY_FLAG_ZERO_PADDED))
222 memset (data + offset + size, 0, padding);
224 _default_mem_init (mem, flags, NULL, slice_size, data, maxsize,
225 offset, size, align, NULL, NULL);
231 _default_alloc_alloc (GstAllocator * allocator, gsize size,
232 GstAllocationParams * params, gpointer user_data)
234 gsize maxsize = size + params->prefix + params->padding;
236 return (GstMemory *) _default_mem_new_block (params->flags,
237 maxsize, params->align, params->prefix, size);
241 _default_mem_map (GstMemoryDefault * mem, gsize maxsize, GstMapFlags flags)
247 _default_mem_unmap (GstMemoryDefault * mem)
253 _default_mem_free (GstMemoryDefault * mem)
255 GST_CAT_DEBUG (GST_CAT_MEMORY, "free memory %p", mem);
258 gst_memory_unref (mem->mem.parent);
261 mem->notify (mem->user_data);
263 g_slice_free1 (mem->slice_size, mem);
266 static GstMemoryDefault *
267 _default_mem_copy (GstMemoryDefault * mem, gssize offset, gsize size)
269 GstMemoryDefault *copy;
272 size = mem->mem.size > offset ? mem->mem.size - offset : 0;
275 _default_mem_new_block (0, mem->mem.maxsize, 0, mem->mem.offset + offset,
277 GST_CAT_DEBUG (GST_CAT_PERFORMANCE,
278 "memcpy %" G_GSIZE_FORMAT " memory %p -> %p", mem->mem.maxsize, mem,
280 memcpy (copy->data, mem->data, mem->mem.maxsize);
285 static GstMemoryDefault *
286 _default_mem_share (GstMemoryDefault * mem, gssize offset, gsize size)
288 GstMemoryDefault *sub;
291 /* find the real parent */
292 if ((parent = mem->mem.parent) == NULL)
293 parent = (GstMemory *) mem;
296 size = mem->mem.size - offset;
299 _default_mem_new (GST_MINI_OBJECT_FLAGS (parent), parent, mem->data,
300 mem->mem.maxsize, mem->mem.offset + offset, size, mem->mem.align, NULL,
307 _default_mem_is_span (GstMemoryDefault * mem1, GstMemoryDefault * mem2,
312 GstMemoryDefault *parent;
314 parent = (GstMemoryDefault *) mem1->mem.parent;
316 *offset = mem1->mem.offset - parent->mem.offset;
319 /* and memory is contiguous */
320 return mem1->data + mem1->mem.offset + mem1->mem.size ==
321 mem2->data + mem2->mem.offset;
325 _fallback_mem_copy (GstMemory * mem, gssize offset, gssize size)
328 GstMapInfo sinfo, dinfo;
329 GstAllocationParams params = { 0, 0, 0, mem->align, };
331 if (!gst_memory_map (mem, &sinfo, GST_MAP_READ))
335 size = sinfo.size > offset ? sinfo.size - offset : 0;
337 /* use the same allocator as the memory we copy */
338 copy = gst_allocator_alloc (mem->allocator, size, ¶ms);
339 if (!gst_memory_map (copy, &dinfo, GST_MAP_WRITE)) {
340 GST_CAT_WARNING (GST_CAT_MEMORY, "could not write map memory %p", copy);
341 gst_memory_unmap (mem, &sinfo);
345 GST_CAT_DEBUG (GST_CAT_PERFORMANCE,
346 "memcpy %" G_GSSIZE_FORMAT " memory %p -> %p", size, mem, copy);
347 memcpy (dinfo.data, sinfo.data + offset, size);
348 gst_memory_unmap (copy, &dinfo);
349 gst_memory_unmap (mem, &sinfo);
355 _fallback_mem_is_span (GstMemory * mem1, GstMemory * mem2, gsize * offset)
361 static GHashTable *allocators;
364 _priv_sysmem_notify (gpointer user_data)
366 g_warning ("The default memory allocator was freed!");
370 _priv_gst_memory_initialize (void)
372 static const GstMemoryInfo _mem_info = {
373 GST_ALLOCATOR_SYSMEM,
374 (GstAllocatorAllocFunction) _default_alloc_alloc,
375 (GstMemoryMapFunction) _default_mem_map,
376 (GstMemoryUnmapFunction) _default_mem_unmap,
377 (GstMemoryFreeFunction) _default_mem_free,
378 (GstMemoryCopyFunction) _default_mem_copy,
379 (GstMemoryShareFunction) _default_mem_share,
380 (GstMemoryIsSpanFunction) _default_mem_is_span,
383 g_rw_lock_init (&lock);
384 allocators = g_hash_table_new (g_str_hash, g_str_equal);
386 #ifdef HAVE_GETPAGESIZE
387 #ifdef MEMORY_ALIGNMENT_PAGESIZE
388 gst_memory_alignment = getpagesize () - 1;
392 GST_CAT_DEBUG (GST_CAT_MEMORY, "memory alignment: %" G_GSIZE_FORMAT,
393 gst_memory_alignment);
395 _default_mem_impl = gst_allocator_new (&_mem_info, NULL, _priv_sysmem_notify);
397 _default_allocator = gst_allocator_ref (_default_mem_impl);
398 gst_allocator_register (GST_ALLOCATOR_SYSMEM,
399 gst_allocator_ref (_default_mem_impl));
403 * gst_memory_new_wrapped:
404 * @flags: #GstMemoryFlags
405 * @data: data to wrap
406 * @maxsize: allocated size of @data
407 * @offset: offset in @data
408 * @size: size of valid data
409 * @user_data: user_data
410 * @notify: called with @user_data when the memory is freed
412 * Allocate a new memory block that wraps the given @data.
414 * The prefix/padding must be filled with 0 if @flags contains
415 * #GST_MEMORY_FLAG_ZERO_PREFIXED and #GST_MEMORY_FLAG_ZERO_PADDED respectively.
417 * Returns: a new #GstMemory.
420 gst_memory_new_wrapped (GstMemoryFlags flags, gpointer data,
421 gsize maxsize, gsize offset, gsize size, gpointer user_data,
422 GDestroyNotify notify)
424 GstMemoryDefault *mem;
426 g_return_val_if_fail (data != NULL, NULL);
427 g_return_val_if_fail (offset + size <= maxsize, NULL);
430 _default_mem_new (flags, NULL, data, maxsize, offset, size, 0, user_data,
433 return (GstMemory *) mem;
437 * gst_memory_is_exclusive:
440 * Check if the current ref to @mem is exclusive, this means that no other
441 * references exist other than @mem.
444 gst_memory_is_exclusive (GstMemory * mem)
446 g_return_val_if_fail (mem != NULL, FALSE);
448 return GST_MINI_OBJECT_REFCOUNT_VALUE (mem) == 1;
452 * gst_memory_get_sizes:
454 * @offset: pointer to offset
455 * @maxsize: pointer to maxsize
457 * Get the current @size, @offset and @maxsize of @mem.
459 * Returns: the current sizes of @mem
462 gst_memory_get_sizes (GstMemory * mem, gsize * offset, gsize * maxsize)
464 g_return_val_if_fail (mem != NULL, 0);
467 *offset = mem->offset;
469 *maxsize = mem->maxsize;
477 * @offset: a new offset
480 * Resize the memory region. @mem should be writable and offset + size should be
481 * less than the maxsize of @mem.
483 * #GST_MEMORY_FLAG_ZERO_PREFIXED and #GST_MEMORY_FLAG_ZERO_PADDED will be
484 * cleared when offset or padding is increased respectively.
487 gst_memory_resize (GstMemory * mem, gssize offset, gsize size)
489 g_return_if_fail (mem != NULL);
490 g_return_if_fail (offset >= 0 || mem->offset >= -offset);
491 g_return_if_fail (size + mem->offset + offset <= mem->maxsize);
493 /* if we increase the prefix, we can't guarantee it is still 0 filled */
494 if ((offset > 0) && GST_MEMORY_IS_ZERO_PREFIXED (mem))
495 GST_MEMORY_FLAG_UNSET (mem, GST_MEMORY_FLAG_ZERO_PREFIXED);
497 /* if we increase the padding, we can't guarantee it is still 0 filled */
498 if ((offset + size < mem->size) && GST_MEMORY_IS_ZERO_PADDED (mem))
499 GST_MEMORY_FLAG_UNSET (mem, GST_MEMORY_FLAG_ZERO_PADDED);
501 mem->offset += offset;
508 * @flags: #GstLockFlags
510 * Lock the memory with the specified access mode in @flags.
512 * Returns: %TRUE if the memory could be locked.
515 gst_memory_lock (GstMemory * mem, GstLockFlags flags)
517 gint access_mode, state, newstate;
519 access_mode = flags & FLAG_MASK;
522 newstate = state = g_atomic_int_get (&mem->state);
524 GST_CAT_TRACE (GST_CAT_MEMORY, "lock %p: state %08x, access_mode %d",
525 mem, state, access_mode);
527 if (access_mode & GST_LOCK_FLAG_EXCLUSIVE) {
529 newstate += SHARE_ONE;
530 access_mode &= ~GST_LOCK_FLAG_EXCLUSIVE;
534 if ((state & LOCK_FLAG_MASK) == 0) {
535 /* shared counter > 1 and write access */
536 if (state > SHARE_ONE && access_mode & GST_LOCK_FLAG_WRITE)
538 /* nothing mapped, set access_mode */
539 newstate |= access_mode;
541 /* access_mode must match */
542 if ((state & access_mode) != access_mode)
545 /* increase refcount */
546 newstate += LOCK_ONE;
548 } while (!g_atomic_int_compare_and_exchange (&mem->state, state, newstate));
554 GST_CAT_DEBUG (GST_CAT_MEMORY, "lock failed %p: state %08x, access_mode %d",
555 mem, state, access_mode);
563 * @flags: #GstLockFlags
565 * Unlock the memory with the specified access mode in @flags.
568 gst_memory_unlock (GstMemory * mem, GstLockFlags flags)
570 gint access_mode, state, newstate;
572 access_mode = flags & FLAG_MASK;
575 newstate = state = g_atomic_int_get (&mem->state);
577 GST_CAT_TRACE (GST_CAT_MEMORY, "unlock %p: state %08x, access_mode %d",
578 mem, state, access_mode);
580 if (access_mode & GST_LOCK_FLAG_EXCLUSIVE) {
582 g_return_if_fail (state >= SHARE_ONE);
583 newstate = state - SHARE_ONE;
584 access_mode &= ~GST_LOCK_FLAG_EXCLUSIVE;
588 g_return_if_fail ((state & access_mode) == access_mode);
589 /* decrease the refcount */
590 newstate -= LOCK_ONE;
591 /* last refcount, unset access_mode */
592 if ((newstate & LOCK_FLAG_MASK) == access_mode)
593 newstate &= ~LOCK_FLAG_MASK;
595 } while (!g_atomic_int_compare_and_exchange (&mem->state, state, newstate));
599 * gst_memory_make_mapped:
600 * @mem: (transfer full): a #GstMemory
601 * @info: (out): pointer for info
602 * @flags: mapping flags
604 * Create a #GstMemory object that is mapped with @flags. If @mem is mappable
605 * with @flags, this function returns the mapped @mem directly. Otherwise a
606 * mapped copy of @mem is returned.
608 * This function takes ownership of old @mem and returns a reference to a new
611 * Returns: (transfer full): a #GstMemory object mapped with @flags or NULL when
612 * a mapping is not possible.
615 gst_memory_make_mapped (GstMemory * mem, GstMapInfo * info, GstMapFlags flags)
619 if (gst_memory_map (mem, info, flags)) {
622 result = gst_memory_copy (mem, 0, -1);
623 gst_memory_unref (mem);
628 if (!gst_memory_map (result, info, flags))
636 GST_CAT_DEBUG (GST_CAT_MEMORY, "cannot copy memory %p", mem);
641 GST_CAT_DEBUG (GST_CAT_MEMORY, "cannot map memory %p with flags %d", mem,
643 gst_memory_unref (result);
651 * @info: (out): pointer for info
652 * @flags: mapping flags
654 * Fill @info with the pointer and sizes of the memory in @mem that can be
655 * accessed according to @flags.
657 * This function can return %FALSE for various reasons:
658 * - the memory backed by @mem is not accessible with the given @flags.
659 * - the memory was already mapped with a different mapping.
661 * @info and its contents remain valid for as long as @mem is valid and
662 * until gst_memory_unmap() is called.
664 * For each gst_memory_map() call, a corresponding gst_memory_unmap() call
667 * Returns: %TRUE if the map operation was successful.
670 gst_memory_map (GstMemory * mem, GstMapInfo * info, GstMapFlags flags)
672 g_return_val_if_fail (mem != NULL, FALSE);
673 g_return_val_if_fail (info != NULL, FALSE);
675 if (!gst_memory_lock (mem, flags))
678 info->data = mem->allocator->info.mem_map (mem, mem->maxsize, flags);
680 if (G_UNLIKELY (info->data == NULL))
685 info->size = mem->size;
686 info->maxsize = mem->maxsize - mem->offset;
687 info->data = info->data + mem->offset;
694 GST_CAT_DEBUG (GST_CAT_MEMORY, "mem %p: lock %d failed", mem, flags);
699 /* something went wrong, restore the orginal state again */
700 GST_CAT_ERROR (GST_CAT_MEMORY, "mem %p: map failed", mem);
701 gst_memory_unlock (mem, flags);
709 * @info: a #GstMapInfo
711 * Release the memory obtained with gst_memory_map()
714 gst_memory_unmap (GstMemory * mem, GstMapInfo * info)
716 g_return_if_fail (mem != NULL);
717 g_return_if_fail (info != NULL);
718 g_return_if_fail (info->memory == mem);
719 /* there must be a ref */
720 g_return_if_fail (g_atomic_int_get (&mem->state) >= 4);
722 mem->allocator->info.mem_unmap (mem);
723 gst_memory_unlock (mem, info->flags);
729 * @offset: an offset to copy
730 * @size: size to copy or -1 to copy all bytes from offset
732 * Return a copy of @size bytes from @mem starting from @offset. This copy is
733 * guaranteed to be writable. @size can be set to -1 to return a copy all bytes
736 * Returns: a new #GstMemory.
739 gst_memory_copy (GstMemory * mem, gssize offset, gssize size)
743 g_return_val_if_fail (mem != NULL, NULL);
745 copy = mem->allocator->info.mem_copy (mem, offset, size);
753 * @offset: an offset to share
754 * @size: size to share or -1 to share bytes from offset
756 * Return a shared copy of @size bytes from @mem starting from @offset. No
757 * memory copy is performed and the memory region is simply shared. The result
758 * is guaranteed to be not-writable. @size can be set to -1 to return a share
759 * all bytes from @offset.
761 * Returns: a new #GstMemory.
764 gst_memory_share (GstMemory * mem, gssize offset, gssize size)
768 g_return_val_if_fail (mem != NULL, NULL);
769 g_return_val_if_fail (!GST_MEMORY_FLAG_IS_SET (mem, GST_MEMORY_FLAG_NO_SHARE),
772 shared = mem->allocator->info.mem_share (mem, offset, size);
778 * gst_memory_is_span:
779 * @mem1: a #GstMemory
780 * @mem2: a #GstMemory
781 * @offset: a pointer to a result offset
783 * Check if @mem1 and mem2 share the memory with a common parent memory object
784 * and that the memory is contiguous.
786 * If this is the case, the memory of @mem1 and @mem2 can be merged
787 * efficiently by performing gst_memory_share() on the parent object from
788 * the returned @offset.
790 * Returns: %TRUE if the memory is contiguous and of a common parent.
793 gst_memory_is_span (GstMemory * mem1, GstMemory * mem2, gsize * offset)
795 g_return_val_if_fail (mem1 != NULL, FALSE);
796 g_return_val_if_fail (mem2 != NULL, FALSE);
798 /* need to have the same allocators */
799 if (mem1->allocator != mem2->allocator)
802 /* need to have the same parent */
803 if (mem1->parent == NULL || mem1->parent != mem2->parent)
806 /* and memory is contiguous */
807 if (!mem1->allocator->info.mem_is_span (mem1, mem2, offset))
814 _gst_allocator_free (GstAllocator * allocator)
816 if (allocator->notify)
817 allocator->notify (allocator->user_data);
819 g_slice_free1 (sizeof (GstAllocator), allocator);
822 static GstAllocator *
823 _gst_allocator_copy (GstAllocator * allocator)
825 return gst_allocator_ref (allocator);
830 * @info: a #GstMemoryInfo
831 * @user_data: user data
832 * @notify: a #GDestroyNotify for @user_data
834 * Create a new memory allocator with @info and @user_data.
836 * All functions in @info are mandatory exept the copy and is_span
837 * functions, which will have a default implementation when left NULL.
839 * The @user_data will be passed to all calls of the alloc function. @notify
840 * will be called with @user_data when the allocator is freed.
842 * Returns: a new #GstAllocator.
845 gst_allocator_new (const GstMemoryInfo * info, gpointer user_data,
846 GDestroyNotify notify)
848 GstAllocator *allocator;
850 g_return_val_if_fail (info != NULL, NULL);
851 g_return_val_if_fail (info->alloc != NULL, NULL);
852 g_return_val_if_fail (info->mem_map != NULL, NULL);
853 g_return_val_if_fail (info->mem_unmap != NULL, NULL);
854 g_return_val_if_fail (info->mem_free != NULL, NULL);
855 g_return_val_if_fail (info->mem_share != NULL, NULL);
857 allocator = g_slice_new0 (GstAllocator);
859 gst_mini_object_init (GST_MINI_OBJECT_CAST (allocator), GST_TYPE_ALLOCATOR,
860 (GstMiniObjectCopyFunction) _gst_allocator_copy, NULL,
861 (GstMiniObjectFreeFunction) _gst_allocator_free);
863 allocator->info = *info;
864 allocator->user_data = user_data;
865 allocator->notify = notify;
867 #define INSTALL_FALLBACK(_t) \
868 if (allocator->info._t == NULL) allocator->info._t = _fallback_ ##_t;
869 INSTALL_FALLBACK (mem_copy);
870 INSTALL_FALLBACK (mem_is_span);
871 #undef INSTALL_FALLBACK
873 GST_CAT_DEBUG (GST_CAT_MEMORY, "new allocator %p", allocator);
879 * gst_allocator_get_memory_type:
880 * @allocator: a #GstAllocator
882 * Get the memory type allocated by this allocator
884 * Returns: the memory type provided by @allocator
887 gst_allocator_get_memory_type (GstAllocator * allocator)
889 g_return_val_if_fail (allocator != NULL, NULL);
891 return allocator->info.mem_type;
895 * gst_allocator_register:
896 * @name: the name of the allocator
897 * @allocator: (transfer full): #GstAllocator
899 * Registers the memory @allocator with @name. This function takes ownership of
903 gst_allocator_register (const gchar * name, GstAllocator * allocator)
905 g_return_if_fail (name != NULL);
906 g_return_if_fail (allocator != NULL);
908 GST_CAT_DEBUG (GST_CAT_MEMORY, "registering allocator %p with name \"%s\"",
911 g_rw_lock_writer_lock (&lock);
912 g_hash_table_insert (allocators, (gpointer) name, (gpointer) allocator);
913 g_rw_lock_writer_unlock (&lock);
917 * gst_allocator_find:
918 * @name: the name of the allocator
920 * Find a previously registered allocator with @name. When @name is NULL, the
921 * default allocator will be returned.
923 * Returns: (transfer full): a #GstAllocator or NULL when the allocator with @name was not
924 * registered. Use gst_allocator_unref() to release the allocator after usage.
927 gst_allocator_find (const gchar * name)
929 GstAllocator *allocator;
931 g_rw_lock_reader_lock (&lock);
933 allocator = g_hash_table_lookup (allocators, (gconstpointer) name);
935 allocator = _default_allocator;
938 gst_allocator_ref (allocator);
939 g_rw_lock_reader_unlock (&lock);
945 * gst_allocator_set_default:
946 * @allocator: (transfer full): a #GstAllocator
948 * Set the default allocator. This function takes ownership of @allocator.
951 gst_allocator_set_default (GstAllocator * allocator)
954 g_return_if_fail (allocator != NULL);
956 g_rw_lock_writer_lock (&lock);
957 old = _default_allocator;
958 _default_allocator = allocator;
959 g_rw_lock_writer_unlock (&lock);
962 gst_allocator_unref (old);
966 * gst_allocation_params_init:
967 * @params: a #GstAllocationParams
969 * Initialize @params to its default values
972 gst_allocation_params_init (GstAllocationParams * params)
974 g_return_if_fail (params != NULL);
976 memset (params, 0, sizeof (GstAllocationParams));
980 * gst_allocation_params_copy:
981 * @params: (transfer none): a #GstAllocationParams
983 * Create a copy of @params.
985 * Free-function: gst_allocation_params_free
987 * Returns: (transfer full): a new ##GstAllocationParams, free with
988 * gst_allocation_params_free().
990 GstAllocationParams *
991 gst_allocation_params_copy (const GstAllocationParams * params)
993 GstAllocationParams *result = NULL;
997 (GstAllocationParams *) g_slice_copy (sizeof (GstAllocationParams),
1004 * gst_allocation_params_free:
1005 * @params: (in) (transfer full): a #GstAllocationParams
1010 gst_allocation_params_free (GstAllocationParams * params)
1012 g_slice_free (GstAllocationParams, params);
1016 * gst_allocator_alloc:
1017 * @allocator: (transfer none) (allow-none): a #GstAllocator to use
1018 * @size: size of the visible memory area
1019 * @params: (transfer none) (allow-none): optional parameters
1021 * Use @allocator to allocate a new memory block with memory that is at least
1024 * The optional @params can specify the prefix and padding for the memory. If
1025 * NULL is passed, no flags, no extra prefix/padding and a default alignment is
1028 * The prefix/padding will be filled with 0 if flags contains
1029 * #GST_MEMORY_FLAG_ZERO_PREFIXED and #GST_MEMORY_FLAG_ZERO_PADDED respectively.
1031 * When @allocator is NULL, the default allocator will be used.
1033 * The alignment in @params is given as a bitmask so that @align + 1 equals
1034 * the amount of bytes to align to. For example, to align to 8 bytes,
1035 * use an alignment of 7.
1037 * Returns: (transfer full): a new #GstMemory.
1040 gst_allocator_alloc (GstAllocator * allocator, gsize size,
1041 GstAllocationParams * params)
1044 static GstAllocationParams defparams = { 0, 0, 0, 0, };
1047 g_return_val_if_fail (((params->align + 1) & params->align) == 0, NULL);
1049 params = &defparams;
1052 if (allocator == NULL)
1053 allocator = _default_allocator;
1055 mem = allocator->info.alloc (allocator, size, params, allocator->user_data);