2 * Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
3 * 2000 Wim Taymans <wtay@chello.be>
5 * gstbuffer.c: Buffer operations
7 * This library is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Library General Public
9 * License as published by the Free Software Foundation; either
10 * version 2 of the License, or (at your option) any later version.
12 * This library is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Library General Public License for more details.
17 * You should have received a copy of the GNU Library General Public
18 * License along with this library; if not, write to the
19 * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
20 * Boston, MA 02110-1301, USA.
25 * @short_description: Data-passing buffer type
26 * @see_also: #GstPad, #GstMiniObject, #GstMemory, #GstMeta, #GstBufferPool
28 * Buffers are the basic unit of data transfer in GStreamer. They contain the
29 * timing and offset along with other arbitrary metadata that is associated
30 * with the #GstMemory blocks that the buffer contains.
32 * Buffers are usually created with gst_buffer_new(). After a buffer has been
33 * created one will typically allocate memory for it and add it to the buffer.
34 * The following example creates a buffer that can hold a given video frame
35 * with a given width, height and bits per plane.
37 * <title>Creating a buffer for a video frame</title>
41 * gint size, width, height, bpp;
43 * size = width * height * bpp;
44 * buffer = gst_buffer_new ();
45 * memory = gst_allocator_alloc (NULL, size, NULL);
46 * gst_buffer_insert_memory (buffer, -1, memory);
51 * Alternatively, use gst_buffer_new_allocate()
52 * to create a buffer with preallocated data of a given size.
54 * Buffers can contain a list of #GstMemory objects. You can retrieve how many
55 * memory objects with gst_buffer_n_memory() and you can get a pointer
56 * to memory with gst_buffer_peek_memory()
58 * A buffer will usually have timestamps, and a duration, but neither of these
59 * are guaranteed (they may be set to #GST_CLOCK_TIME_NONE). Whenever a
60 * meaningful value can be given for these, they should be set. The timestamps
61 * and duration are measured in nanoseconds (they are #GstClockTime values).
63 * The buffer DTS refers to the timestamp when the buffer should be decoded and
64 * is usually monotonically increasing. The buffer PTS refers to the timestamp when
65 * the buffer content should be presented to the user and is not always
66 * monotonically increasing.
68 * A buffer can also have one or both of a start and an end offset. These are
69 * media-type specific. For video buffers, the start offset will generally be
70 * the frame number. For audio buffers, it will be the number of samples
71 * produced so far. For compressed data, it could be the byte offset in a
72 * source or destination file. Likewise, the end offset will be the offset of
73 * the end of the buffer. These can only be meaningfully interpreted if you
74 * know the media type of the buffer (the preceeding CAPS event). Either or both
75 * can be set to #GST_BUFFER_OFFSET_NONE.
77 * gst_buffer_ref() is used to increase the refcount of a buffer. This must be
78 * done when you want to keep a handle to the buffer after pushing it to the
79 * next element. The buffer refcount determines the writability of the buffer, a
80 * buffer is only writable when the refcount is exactly 1, i.e. when the caller
81 * has the only reference to the buffer.
83 * To efficiently create a smaller buffer out of an existing one, you can
84 * use gst_buffer_copy_region(). This method tries to share the memory objects
85 * between the two buffers.
87 * If a plug-in wants to modify the buffer data or metadata in-place, it should
88 * first obtain a buffer that is safe to modify by using
89 * gst_buffer_make_writable(). This function is optimized so that a copy will
90 * only be made when it is necessary.
92 * Several flags of the buffer can be set and unset with the
93 * GST_BUFFER_FLAG_SET() and GST_BUFFER_FLAG_UNSET() macros. Use
94 * GST_BUFFER_FLAG_IS_SET() to test if a certain #GstBufferFlags flag is set.
96 * Buffers can be efficiently merged into a larger buffer with
97 * gst_buffer_append(). Copying of memory will only be done when absolutely
100 * Arbitrary extra metadata can be set on a buffer with gst_buffer_add_meta().
101 * Metadata can be retrieved with gst_buffer_get_meta(). See also #GstMeta
103 * An element should either unref the buffer or push it out on a src pad
104 * using gst_pad_push() (see #GstPad).
106 * Buffers are usually freed by unreffing them with gst_buffer_unref(). When
107 * the refcount drops to 0, any memory and metadata pointed to by the buffer is
108 * unreffed as well. Buffers allocated from a #GstBufferPool will be returned to
109 * the pool when the refcount drops to 0.
111 * Last reviewed on 2012-03-28 (0.11.3)
113 #include "gst_private.h"
122 #include "gstbuffer.h"
123 #include "gstbufferpool.h"
125 #include "gstutils.h"
126 #include "gstversion.h"
128 GType _gst_buffer_type = 0;
130 typedef struct _GstMetaItem GstMetaItem;
137 #define ITEM_SIZE(info) ((info)->size + sizeof (GstMetaItem))
139 #define GST_BUFFER_MEM_MAX 16
141 #define GST_BUFFER_SLICE_SIZE(b) (((GstBufferImpl *)(b))->slice_size)
142 #define GST_BUFFER_MEM_LEN(b) (((GstBufferImpl *)(b))->len)
143 #define GST_BUFFER_MEM_ARRAY(b) (((GstBufferImpl *)(b))->mem)
144 #define GST_BUFFER_MEM_PTR(b,i) (((GstBufferImpl *)(b))->mem[i])
145 #define GST_BUFFER_BUFMEM(b) (((GstBufferImpl *)(b))->bufmem)
146 #define GST_BUFFER_META(b) (((GstBufferImpl *)(b))->item)
154 /* the memory blocks */
156 GstMemory *mem[GST_BUFFER_MEM_MAX];
158 /* memory of the buffer when allocated from 1 chunk */
161 /* FIXME, make metadata allocation more efficient by using part of the
168 _is_span (GstMemory ** mem, gsize len, gsize * poffset, GstMemory ** parent)
170 GstMemory *mcur, *mprv;
171 gboolean have_offset = FALSE;
176 for (i = 0; i < len; i++) {
184 /* check if memory is contiguous */
185 if (!gst_memory_is_span (mprv, mcur, &poffs))
192 *parent = mprv->parent;
202 _get_merged_memory (GstBuffer * buffer, guint idx, guint length)
204 GstMemory **mem, *result = NULL;
206 GST_CAT_LOG (GST_CAT_BUFFER, "buffer %p, idx %u, length %u", buffer, idx,
209 mem = GST_BUFFER_MEM_ARRAY (buffer);
211 if (G_UNLIKELY (length == 0)) {
213 } else if (G_LIKELY (length == 1)) {
214 result = gst_memory_ref (mem[idx]);
216 GstMemory *parent = NULL;
217 gsize size, poffset = 0;
219 size = gst_buffer_get_sizes_range (buffer, idx, length, NULL, NULL);
221 if (G_UNLIKELY (_is_span (mem + idx, length, &poffset, &parent))) {
222 if (!GST_MEMORY_IS_NO_SHARE (parent))
223 result = gst_memory_share (parent, poffset, size);
225 GST_CAT_DEBUG (GST_CAT_PERFORMANCE, "copy for merge %p", parent);
226 result = gst_memory_copy (parent, poffset, size);
229 gsize i, tocopy, left;
230 GstMapInfo sinfo, dinfo;
233 result = gst_allocator_alloc (NULL, size, NULL);
234 gst_memory_map (result, &dinfo, GST_MAP_WRITE);
239 for (i = idx; i < (idx + length) && left > 0; i++) {
240 gst_memory_map (mem[i], &sinfo, GST_MAP_READ);
241 tocopy = MIN (sinfo.size, left);
242 GST_CAT_DEBUG (GST_CAT_PERFORMANCE,
243 "memcpy %" G_GSIZE_FORMAT " bytes for merge %p from memory %p",
244 tocopy, result, mem[i]);
245 memcpy (ptr, (guint8 *) sinfo.data, tocopy);
248 gst_memory_unmap (mem[i], &sinfo);
250 gst_memory_unmap (result, &dinfo);
257 _replace_memory (GstBuffer * buffer, guint len, guint idx, guint length,
264 GST_CAT_LOG (GST_CAT_BUFFER,
265 "buffer %p replace %u-%" G_GSIZE_FORMAT " with memory %p", buffer, idx,
268 /* unref old memory */
269 for (i = idx; i < end; i++) {
270 GstMemory *old = GST_BUFFER_MEM_PTR (buffer, i);
272 gst_memory_unlock (old, GST_LOCK_FLAG_EXCLUSIVE);
273 gst_memory_unref (old);
277 /* replace with single memory */
278 gst_memory_lock (mem, GST_LOCK_FLAG_EXCLUSIVE);
279 GST_BUFFER_MEM_PTR (buffer, idx) = mem;
285 memmove (&GST_BUFFER_MEM_PTR (buffer, idx),
286 &GST_BUFFER_MEM_PTR (buffer, end), (len - end) * sizeof (gpointer));
288 GST_BUFFER_MEM_LEN (buffer) = len - length;
292 _memory_add (GstBuffer * buffer, gint idx, GstMemory * mem, gboolean lock)
294 guint i, len = GST_BUFFER_MEM_LEN (buffer);
296 GST_CAT_LOG (GST_CAT_BUFFER, "buffer %p, idx %d, mem %p, lock %d", buffer,
299 if (G_UNLIKELY (len >= GST_BUFFER_MEM_MAX)) {
300 /* too many buffer, span them. */
301 /* FIXME, there is room for improvement here: We could only try to merge
302 * 2 buffers to make some room. If we can't efficiently merge 2 buffers we
303 * could try to only merge the two smallest buffers to avoid memcpy, etc. */
304 GST_CAT_DEBUG (GST_CAT_PERFORMANCE, "memory array overflow in buffer %p",
306 _replace_memory (buffer, len, 0, len, _get_merged_memory (buffer, 0, len));
307 /* we now have 1 single spanned buffer */
314 for (i = len; i > idx; i--) {
315 /* move buffers to insert, FIXME, we need to insert first and then merge */
316 GST_BUFFER_MEM_PTR (buffer, i) = GST_BUFFER_MEM_PTR (buffer, i - 1);
318 /* and insert the new buffer */
320 gst_memory_lock (mem, GST_LOCK_FLAG_EXCLUSIVE);
321 GST_BUFFER_MEM_PTR (buffer, idx) = mem;
322 GST_BUFFER_MEM_LEN (buffer) = len + 1;
325 GST_DEFINE_MINI_OBJECT_TYPE (GstBuffer, gst_buffer);
328 _priv_gst_buffer_initialize (void)
330 _gst_buffer_type = gst_buffer_get_type ();
334 * gst_buffer_get_max_memory:
336 * Get the maximum amount of memory blocks that a buffer can hold. This is a
337 * compile time constant that can be queried with the function.
339 * When more memory blocks are added, existing memory blocks will be merged
340 * together to make room for the new block.
342 * Returns: the maximum amount of memory blocks that a buffer can hold.
347 gst_buffer_get_max_memory (void)
349 return GST_BUFFER_MEM_MAX;
353 * gst_buffer_copy_into:
354 * @dest: a destination #GstBuffer
355 * @src: a source #GstBuffer
356 * @flags: flags indicating what metadata fields should be copied.
357 * @offset: offset to copy from
358 * @size: total size to copy. If -1, all data is copied.
360 * Copies the information from @src into @dest.
362 * If @dest already contains memory and @flags contains GST_BUFFER_COPY_MEMORY,
363 * the memory from @src will be appended to @dest.
365 * @flags indicate which fields will be copied.
367 * Returns: %TRUE if the copying succeeded, %FALSE otherwise.
370 gst_buffer_copy_into (GstBuffer * dest, GstBuffer * src,
371 GstBufferCopyFlags flags, gsize offset, gsize size)
375 gboolean region = FALSE;
377 g_return_val_if_fail (dest != NULL, FALSE);
378 g_return_val_if_fail (src != NULL, FALSE);
380 /* nothing to copy if the buffers are the same */
381 if (G_UNLIKELY (dest == src))
384 g_return_val_if_fail (gst_buffer_is_writable (dest), FALSE);
386 bufsize = gst_buffer_get_size (src);
387 g_return_val_if_fail (bufsize >= offset, FALSE);
391 size = bufsize - offset;
394 g_return_val_if_fail (bufsize >= offset + size, FALSE);
396 GST_CAT_LOG (GST_CAT_BUFFER, "copy %p to %p, offset %" G_GSIZE_FORMAT
397 "-%" G_GSIZE_FORMAT "/%" G_GSIZE_FORMAT, src, dest, offset, size,
400 if (flags & GST_BUFFER_COPY_FLAGS) {
402 GST_MINI_OBJECT_FLAGS (dest) = GST_MINI_OBJECT_FLAGS (src);
405 if (flags & GST_BUFFER_COPY_TIMESTAMPS) {
407 GST_BUFFER_PTS (dest) = GST_BUFFER_PTS (src);
408 GST_BUFFER_DTS (dest) = GST_BUFFER_DTS (src);
409 GST_BUFFER_OFFSET (dest) = GST_BUFFER_OFFSET (src);
410 if (size == bufsize) {
411 GST_BUFFER_DURATION (dest) = GST_BUFFER_DURATION (src);
412 GST_BUFFER_OFFSET_END (dest) = GST_BUFFER_OFFSET_END (src);
415 GST_BUFFER_PTS (dest) = GST_CLOCK_TIME_NONE;
416 GST_BUFFER_DTS (dest) = GST_CLOCK_TIME_NONE;
417 GST_BUFFER_DURATION (dest) = GST_CLOCK_TIME_NONE;
418 GST_BUFFER_OFFSET (dest) = GST_BUFFER_OFFSET_NONE;
419 GST_BUFFER_OFFSET_END (dest) = GST_BUFFER_OFFSET_NONE;
423 if (flags & GST_BUFFER_COPY_MEMORY) {
424 gsize skip, left, len, dest_len, i, bsize;
427 deep = flags & GST_BUFFER_COPY_DEEP;
429 len = GST_BUFFER_MEM_LEN (src);
430 dest_len = GST_BUFFER_MEM_LEN (dest);
434 /* copy and make regions of the memory */
435 for (i = 0; i < len && left > 0; i++) {
436 GstMemory *mem = GST_BUFFER_MEM_PTR (src, i);
438 bsize = gst_memory_get_sizes (mem, NULL, NULL);
441 /* don't copy buffer */
444 GstMemory *newmem = NULL;
447 tocopy = MIN (bsize - skip, left);
449 if (tocopy < bsize && !deep && !GST_MEMORY_IS_NO_SHARE (mem)) {
450 /* we need to clip something */
451 newmem = gst_memory_share (mem, skip, tocopy);
456 if (deep || GST_MEMORY_IS_NO_SHARE (mem) || (!newmem && tocopy < bsize)) {
457 /* deep copy or we're not allowed to share this memory
458 * between buffers, always copy then */
459 newmem = gst_memory_copy (mem, skip, tocopy);
461 } else if (!newmem) {
462 newmem = gst_memory_ref (mem);
466 gst_buffer_remove_memory_range (dest, dest_len, -1);
470 _memory_add (dest, -1, newmem, TRUE);
474 if (flags & GST_BUFFER_COPY_MERGE) {
477 len = GST_BUFFER_MEM_LEN (dest);
478 mem = _get_merged_memory (dest, 0, len);
480 gst_buffer_remove_memory_range (dest, dest_len, -1);
483 _replace_memory (dest, len, 0, len, mem);
487 if (flags & GST_BUFFER_COPY_META) {
488 for (walk = GST_BUFFER_META (src); walk; walk = walk->next) {
489 GstMeta *meta = &walk->meta;
490 const GstMetaInfo *info = meta->info;
492 if (info->transform_func) {
493 GstMetaTransformCopy copy_data;
495 copy_data.region = region;
496 copy_data.offset = offset;
497 copy_data.size = size;
499 info->transform_func (dest, meta, src,
500 _gst_meta_transform_copy, ©_data);
509 _gst_buffer_copy (GstBuffer * buffer)
513 g_return_val_if_fail (buffer != NULL, NULL);
515 /* create a fresh new buffer */
516 copy = gst_buffer_new ();
518 /* we simply copy everything from our parent */
519 if (!gst_buffer_copy_into (copy, buffer, GST_BUFFER_COPY_ALL, 0, -1))
520 gst_buffer_replace (©, NULL);
525 /* the default dispose function revives the buffer and returns it to the
526 * pool when there is a pool */
528 _gst_buffer_dispose (GstBuffer * buffer)
532 /* no pool, do free */
533 if ((pool = buffer->pool) == NULL)
536 /* keep the buffer alive */
537 gst_buffer_ref (buffer);
538 /* return the buffer to the pool */
539 GST_CAT_LOG (GST_CAT_BUFFER, "release %p to pool %p", buffer, pool);
540 gst_buffer_pool_release_buffer (pool, buffer);
546 _gst_buffer_free (GstBuffer * buffer)
548 GstMetaItem *walk, *next;
552 g_return_if_fail (buffer != NULL);
554 GST_CAT_LOG (GST_CAT_BUFFER, "finalize %p", buffer);
557 for (walk = GST_BUFFER_META (buffer); walk; walk = next) {
558 GstMeta *meta = &walk->meta;
559 const GstMetaInfo *info = meta->info;
561 /* call free_func if any */
563 info->free_func (meta, buffer);
566 /* and free the slice */
567 g_slice_free1 (ITEM_SIZE (info), walk);
570 /* get the size, when unreffing the memory, we could also unref the buffer
572 msize = GST_BUFFER_SLICE_SIZE (buffer);
574 /* free our memory */
575 len = GST_BUFFER_MEM_LEN (buffer);
576 for (i = 0; i < len; i++) {
577 gst_memory_unlock (GST_BUFFER_MEM_PTR (buffer, i), GST_LOCK_FLAG_EXCLUSIVE);
578 gst_memory_unref (GST_BUFFER_MEM_PTR (buffer, i));
581 /* we set msize to 0 when the buffer is part of the memory block */
584 memset (buffer, 0xff, msize);
586 g_slice_free1 (msize, buffer);
588 gst_memory_unref (GST_BUFFER_BUFMEM (buffer));
593 gst_buffer_init (GstBufferImpl * buffer, gsize size)
595 gst_mini_object_init (GST_MINI_OBJECT_CAST (buffer), 0, _gst_buffer_type,
596 (GstMiniObjectCopyFunction) _gst_buffer_copy,
597 (GstMiniObjectDisposeFunction) _gst_buffer_dispose,
598 (GstMiniObjectFreeFunction) _gst_buffer_free);
600 GST_BUFFER_SLICE_SIZE (buffer) = size;
602 GST_BUFFER (buffer)->pool = NULL;
603 GST_BUFFER_PTS (buffer) = GST_CLOCK_TIME_NONE;
604 GST_BUFFER_DTS (buffer) = GST_CLOCK_TIME_NONE;
605 GST_BUFFER_DURATION (buffer) = GST_CLOCK_TIME_NONE;
606 GST_BUFFER_OFFSET (buffer) = GST_BUFFER_OFFSET_NONE;
607 GST_BUFFER_OFFSET_END (buffer) = GST_BUFFER_OFFSET_NONE;
609 GST_BUFFER_MEM_LEN (buffer) = 0;
610 GST_BUFFER_META (buffer) = NULL;
616 * Creates a newly allocated buffer without any data.
620 * Returns: (transfer full): the new #GstBuffer.
623 gst_buffer_new (void)
625 GstBufferImpl *newbuf;
627 newbuf = g_slice_new (GstBufferImpl);
628 GST_CAT_LOG (GST_CAT_BUFFER, "new %p", newbuf);
630 gst_buffer_init (newbuf, sizeof (GstBufferImpl));
632 return GST_BUFFER_CAST (newbuf);
636 * gst_buffer_new_allocate:
637 * @allocator: (transfer none) (allow-none): the #GstAllocator to use, or NULL to use the
639 * @size: the size in bytes of the new buffer's data.
640 * @params: (transfer none) (allow-none): optional parameters
642 * Tries to create a newly allocated buffer with data of the given size and
643 * extra parameters from @allocator. If the requested amount of memory can't be
644 * allocated, NULL will be returned. The allocated buffer memory is not cleared.
646 * When @allocator is NULL, the default memory allocator will be used.
648 * Note that when @size == 0, the buffer will not have memory associated with it.
652 * Returns: (transfer full): a new #GstBuffer, or NULL if the memory couldn't
656 gst_buffer_new_allocate (GstAllocator * allocator, gsize size,
657 GstAllocationParams * params)
668 mem = gst_allocator_alloc (allocator, size, params);
669 if (G_UNLIKELY (mem == NULL))
675 newbuf = gst_buffer_new ();
678 _memory_add (newbuf, -1, mem, TRUE);
680 GST_CAT_LOG (GST_CAT_BUFFER,
681 "new buffer %p of size %" G_GSIZE_FORMAT " from allocator %p", newbuf,
686 asize = sizeof (GstBufferImpl) + size;
687 data = g_slice_alloc (asize);
688 if (G_UNLIKELY (data == NULL))
691 newbuf = GST_BUFFER_CAST (data);
693 gst_buffer_init ((GstBufferImpl *) data, asize);
695 mem = gst_memory_new_wrapped (0, data + sizeof (GstBufferImpl), NULL,
697 _memory_add (newbuf, -1, mem, TRUE);
702 /* allocate memory and buffer, it might be interesting to do this but there
703 * are many complications. We need to keep the memory mapped to access the
704 * buffer fields and the memory for the buffer might be just very slow. We
705 * also need to do some more magic to get the alignment right. */
706 asize = sizeof (GstBufferImpl) + size;
707 mem = gst_allocator_alloc (allocator, asize, align);
708 if (G_UNLIKELY (mem == NULL))
711 /* map the data part and init the buffer in it, set the buffer size to 0 so
712 * that a finalize won't free the buffer */
713 data = gst_memory_map (mem, &asize, NULL, GST_MAP_WRITE);
714 gst_buffer_init ((GstBufferImpl *) data, 0);
715 gst_memory_unmap (mem);
717 /* strip off the buffer */
718 gst_memory_resize (mem, sizeof (GstBufferImpl), size);
720 newbuf = GST_BUFFER_CAST (data);
721 GST_BUFFER_BUFMEM (newbuf) = mem;
724 _memory_add (newbuf, -1, gst_memory_ref (mem), TRUE);
732 GST_CAT_WARNING (GST_CAT_BUFFER,
733 "failed to allocate %" G_GSIZE_FORMAT " bytes", size);
739 * gst_buffer_new_wrapped_full:
740 * @flags: #GstMemoryFlags
741 * @data: (array length=size) (element-type guint8) (transfer none): data to wrap
742 * @maxsize: allocated size of @data
743 * @offset: offset in @data
744 * @size: size of valid data
745 * @user_data: (allow-none): user_data
746 * @notify: (allow-none) (scope async) (closure user_data): called with @user_data when the memory is freed
748 * Allocate a new buffer that wraps the given memory. @data must point to
749 * @maxsize of memory, the wrapped buffer will have the region from @offset and
752 * When the buffer is destroyed, @notify will be called with @user_data.
754 * The prefix/padding must be filled with 0 if @flags contains
755 * #GST_MEMORY_FLAG_ZERO_PREFIXED and #GST_MEMORY_FLAG_ZERO_PADDED respectively.
757 * Returns: (transfer full): a new #GstBuffer
760 gst_buffer_new_wrapped_full (GstMemoryFlags flags, gpointer data,
761 gsize maxsize, gsize offset, gsize size, gpointer user_data,
762 GDestroyNotify notify)
767 newbuf = gst_buffer_new ();
769 gst_memory_new_wrapped (flags, data, maxsize, offset, size, user_data,
771 _memory_add (newbuf, -1, mem, TRUE);
777 * gst_buffer_new_wrapped:
778 * @data: (array length=size) (element-type guint8) (transfer full): data to wrap
779 * @size: allocated size of @data
781 * Creates a new buffer that wraps the given @data. The memory will be freed
782 * with g_free and will be marked writable.
786 * Returns: (transfer full): a new #GstBuffer
789 gst_buffer_new_wrapped (gpointer data, gsize size)
791 return gst_buffer_new_wrapped_full (0, data, size, 0, size, data, g_free);
795 * gst_buffer_n_memory:
796 * @buffer: a #GstBuffer.
798 * Get the amount of memory blocks that this buffer has. This amount is never
799 * larger than what gst_buffer_get_max_memory() returns.
801 * Returns: (transfer full): the amount of memory block in this buffer.
804 gst_buffer_n_memory (GstBuffer * buffer)
806 g_return_val_if_fail (GST_IS_BUFFER (buffer), 0);
808 return GST_BUFFER_MEM_LEN (buffer);
812 * gst_buffer_prepend_memory:
813 * @buffer: a #GstBuffer.
814 * @mem: (transfer full): a #GstMemory.
816 * Prepend the memory block @mem to @buffer. This function takes
817 * ownership of @mem and thus doesn't increase its refcount.
819 * This function is identical to gst_buffer_insert_memory() with an index of 0.
820 * See gst_buffer_insert_memory() for more details.
823 gst_buffer_prepend_memory (GstBuffer * buffer, GstMemory * mem)
825 gst_buffer_insert_memory (buffer, 0, mem);
829 * gst_buffer_append_memory:
830 * @buffer: a #GstBuffer.
831 * @mem: (transfer full): a #GstMemory.
833 * Append the memory block @mem to @buffer. This function takes
834 * ownership of @mem and thus doesn't increase its refcount.
836 * This function is identical to gst_buffer_insert_memory() with an index of -1.
837 * See gst_buffer_insert_memory() for more details.
840 gst_buffer_append_memory (GstBuffer * buffer, GstMemory * mem)
842 gst_buffer_insert_memory (buffer, -1, mem);
846 * gst_buffer_insert_memory:
847 * @buffer: a #GstBuffer.
848 * @idx: the index to add the memory at, or -1 to append it to the end
849 * @mem: (transfer full): a #GstMemory.
851 * Insert the memory block @mem to @buffer at @idx. This function takes ownership
852 * of @mem and thus doesn't increase its refcount.
854 * Only gst_buffer_get_max_memory() can be added to a buffer. If more memory is
855 * added, existing memory blocks will automatically be merged to make room for
859 gst_buffer_insert_memory (GstBuffer * buffer, gint idx, GstMemory * mem)
861 g_return_if_fail (GST_IS_BUFFER (buffer));
862 g_return_if_fail (gst_buffer_is_writable (buffer));
863 g_return_if_fail (mem != NULL);
864 g_return_if_fail (idx == -1 ||
865 (idx >= 0 && idx <= GST_BUFFER_MEM_LEN (buffer)));
867 _memory_add (buffer, idx, mem, TRUE);
871 _get_mapped (GstBuffer * buffer, guint idx, GstMapInfo * info,
874 GstMemory *mem, *mapped;
876 mem = gst_memory_ref (GST_BUFFER_MEM_PTR (buffer, idx));
878 mapped = gst_memory_make_mapped (mem, info, flags);
881 /* memory changed, lock new memory */
882 gst_memory_lock (mapped, GST_LOCK_FLAG_EXCLUSIVE);
883 GST_BUFFER_MEM_PTR (buffer, idx) = mapped;
884 /* unlock old memory */
885 gst_memory_unlock (mem, GST_LOCK_FLAG_EXCLUSIVE);
887 gst_memory_unref (mem);
893 * gst_buffer_peek_memory:
894 * @buffer: a #GstBuffer.
897 * Get the memory block at @idx in @buffer. The memory block stays valid until
898 * the memory block in @buffer is removed, replaced or merged, typically with
899 * any call that modifies the memory in @buffer.
901 * Since this call does not influence the refcount of the memory,
902 * gst_memory_is_writable() can be used to check if @buffer is the sole owner
903 * of the returned memory.
905 * Returns: (transfer none): the #GstMemory at @idx.
908 gst_buffer_peek_memory (GstBuffer * buffer, guint idx)
912 g_return_val_if_fail (GST_IS_BUFFER (buffer), NULL);
913 len = GST_BUFFER_MEM_LEN (buffer);
914 g_return_val_if_fail (idx < len, NULL);
916 return GST_BUFFER_MEM_PTR (buffer, idx);
920 * gst_buffer_get_memory:
921 * @buffer: a #GstBuffer.
924 * Get the memory block at index @idx in @buffer.
926 * Returns: (transfer full): a #GstMemory that contains the data of the
927 * memory block at @idx. Use gst_memory_unref () after usage.
930 gst_buffer_get_memory (GstBuffer * buffer, guint idx)
932 return gst_buffer_get_memory_range (buffer, idx, 1);
936 * gst_buffer_get_all_memory:
937 * @buffer: a #GstBuffer.
939 * Get all the memory block in @buffer. The memory blocks will be merged
940 * into one large #GstMemory.
942 * Returns: (transfer full): a #GstMemory that contains the merged memory.
943 * Use gst_memory_unref () after usage.
946 gst_buffer_get_all_memory (GstBuffer * buffer)
948 return gst_buffer_get_memory_range (buffer, 0, -1);
952 * gst_buffer_get_memory_range:
953 * @buffer: a #GstBuffer.
957 * Get @length memory blocks in @buffer starting at @idx. The memory blocks will
958 * be merged into one large #GstMemory.
960 * If @length is -1, all memory starting from @idx is merged.
962 * Returns: (transfer full): a #GstMemory that contains the merged data of @length
963 * blocks starting at @idx. Use gst_memory_unref () after usage.
966 gst_buffer_get_memory_range (GstBuffer * buffer, guint idx, gint length)
970 GST_CAT_DEBUG (GST_CAT_BUFFER, "idx %u, length %d", idx, length);
972 g_return_val_if_fail (GST_IS_BUFFER (buffer), NULL);
973 len = GST_BUFFER_MEM_LEN (buffer);
974 g_return_val_if_fail ((len == 0 && idx == 0 && length == -1) ||
975 (length == -1 && idx < len) || (length > 0 && length + idx <= len), NULL);
980 return _get_merged_memory (buffer, idx, length);
984 * gst_buffer_replace_memory:
985 * @buffer: a #GstBuffer.
987 * @mem: (transfer full): a #GstMemory
989 * Replaces the memory block at index @idx in @buffer with @mem.
992 gst_buffer_replace_memory (GstBuffer * buffer, guint idx, GstMemory * mem)
994 gst_buffer_replace_memory_range (buffer, idx, 1, mem);
998 * gst_buffer_replace_all_memory:
999 * @buffer: a #GstBuffer.
1000 * @mem: (transfer full): a #GstMemory
1002 * Replaces all memory in @buffer with @mem.
1005 gst_buffer_replace_all_memory (GstBuffer * buffer, GstMemory * mem)
1007 gst_buffer_replace_memory_range (buffer, 0, -1, mem);
1011 * gst_buffer_replace_memory_range:
1012 * @buffer: a #GstBuffer.
1014 * @length: a length should not be 0
1015 * @mem: (transfer full): a #GstMemory
1017 * Replaces @length memory blocks in @buffer starting at @idx with @mem.
1019 * If @length is -1, all memory starting from @idx will be removed and
1020 * replaced with @mem.
1022 * @buffer should be writable.
1025 gst_buffer_replace_memory_range (GstBuffer * buffer, guint idx, gint length,
1030 g_return_if_fail (GST_IS_BUFFER (buffer));
1031 g_return_if_fail (gst_buffer_is_writable (buffer));
1033 GST_CAT_DEBUG (GST_CAT_BUFFER, "idx %u, length %d, %p", idx, length, mem);
1035 len = GST_BUFFER_MEM_LEN (buffer);
1036 g_return_if_fail ((len == 0 && idx == 0 && length == -1) ||
1037 (length == -1 && idx < len) || (length > 0 && length + idx <= len));
1042 _replace_memory (buffer, len, idx, length, mem);
1046 * gst_buffer_remove_memory:
1047 * @buffer: a #GstBuffer.
1050 * Remove the memory block in @b at index @i.
1053 gst_buffer_remove_memory (GstBuffer * buffer, guint idx)
1055 gst_buffer_remove_memory_range (buffer, idx, 1);
1059 * gst_buffer_remove_all_memory:
1060 * @buffer: a #GstBuffer.
1062 * Remove all the memory blocks in @buffer.
1065 gst_buffer_remove_all_memory (GstBuffer * buffer)
1067 gst_buffer_remove_memory_range (buffer, 0, -1);
1071 * gst_buffer_remove_memory_range:
1072 * @buffer: a #GstBuffer.
1076 * Remove @length memory blocks in @buffer starting from @idx.
1078 * @length can be -1, in which case all memory starting from @idx is removed.
1081 gst_buffer_remove_memory_range (GstBuffer * buffer, guint idx, gint length)
1085 g_return_if_fail (GST_IS_BUFFER (buffer));
1086 g_return_if_fail (gst_buffer_is_writable (buffer));
1088 GST_CAT_DEBUG (GST_CAT_BUFFER, "idx %u, length %d", idx, length);
1090 len = GST_BUFFER_MEM_LEN (buffer);
1091 g_return_if_fail ((len == 0 && idx == 0 && length == -1) ||
1092 (length == -1 && idx < len) || length + idx <= len);
1097 _replace_memory (buffer, len, idx, length, NULL);
1101 * gst_buffer_find_memory:
1102 * @buffer: a #GstBuffer.
1103 * @offset: an offset
1105 * @idx: (out): pointer to index
1106 * @length: (out): pointer to length
1107 * @skip: (out): pointer to skip
1109 * Find the memory blocks that span @size bytes starting from @offset
1112 * When this function returns %TRUE, @idx will contain the index of the first
1113 * memory bock where the byte for @offset can be found and @length contains the
1114 * number of memory blocks containing the @size remaining bytes. @skip contains
1115 * the number of bytes to skip in the memory bock at @idx to get to the byte
1118 * @size can be -1 to get all the memory blocks after @idx.
1120 * Returns: %TRUE when @size bytes starting from @offset could be found in
1121 * @buffer and @idx, @length and @skip will be filled.
1124 gst_buffer_find_memory (GstBuffer * buffer, gsize offset, gsize size,
1125 guint * idx, guint * length, gsize * skip)
1127 guint i, len, found;
1129 g_return_val_if_fail (GST_IS_BUFFER (buffer), FALSE);
1130 g_return_val_if_fail (idx != NULL, FALSE);
1131 g_return_val_if_fail (length != NULL, FALSE);
1132 g_return_val_if_fail (skip != NULL, FALSE);
1134 len = GST_BUFFER_MEM_LEN (buffer);
1137 for (i = 0; i < len; i++) {
1141 mem = GST_BUFFER_MEM_PTR (buffer, i);
1142 s = gst_memory_get_sizes (mem, NULL, NULL);
1145 /* block before offset, or empty block, skip */
1148 /* block after offset */
1150 /* first block, remember index and offset */
1154 /* return remaining blocks */
1161 /* count the amount of found bytes */
1163 if (found >= size) {
1164 /* we have enough bytes */
1165 *length = i - *idx + 1;
1174 * gst_buffer_get_sizes:
1175 * @buffer: a #GstBuffer.
1176 * @offset: (out): a pointer to the offset
1177 * @maxsize: (out): a pointer to the maxsize
1179 * Get the total size of the memory blocks in @b.
1181 * When not %NULL, @offset will contain the offset of the data in the
1182 * first memory block in @buffer and @maxsize will contain the sum of
1183 * the size and @offset and the amount of extra padding on the last
1184 * memory block. @offset and @maxsize can be used to resize the
1185 * buffer memory blocks with gst_buffer_resize().
1187 * Returns: total size of the memory blocks in @buffer.
1190 gst_buffer_get_sizes (GstBuffer * buffer, gsize * offset, gsize * maxsize)
1192 return gst_buffer_get_sizes_range (buffer, 0, -1, offset, maxsize);
1196 * gst_buffer_get_size:
1197 * @buffer: a #GstBuffer.
1199 * Get the total size of the memory blocks in @buffer.
1201 * Returns: total size of the memory blocks in @buffer.
1204 gst_buffer_get_size (GstBuffer * buffer)
1206 return gst_buffer_get_sizes_range (buffer, 0, -1, NULL, NULL);
1210 * gst_buffer_get_sizes_range:
1211 * @buffer: a #GstBuffer.
1214 * @offset: (out): a pointer to the offset
1215 * @maxsize: (out): a pointer to the maxsize
1217 * Get the total size of @length memory blocks stating from @idx in @buffer.
1219 * When not %NULL, @offset will contain the offset of the data in the
1220 * memory block in @buffer at @idx and @maxsize will contain the sum of the size
1221 * and @offset and the amount of extra padding on the memory block at @idx +
1223 * @offset and @maxsize can be used to resize the buffer memory blocks with
1224 * gst_buffer_resize_range().
1226 * Returns: total size of @length memory blocks starting at @idx in @buffer.
1229 gst_buffer_get_sizes_range (GstBuffer * buffer, guint idx, gint length,
1230 gsize * offset, gsize * maxsize)
1236 g_return_val_if_fail (GST_IS_BUFFER (buffer), 0);
1237 len = GST_BUFFER_MEM_LEN (buffer);
1238 g_return_val_if_fail ((len == 0 && idx == 0 && length == -1) ||
1239 (length == -1 && idx < len) || (length + idx <= len), 0);
1244 if (G_LIKELY (length == 1)) {
1246 mem = GST_BUFFER_MEM_PTR (buffer, idx);
1247 size = gst_memory_get_sizes (mem, offset, maxsize);
1253 size = offs = extra = 0;
1254 for (i = idx; i < end; i++) {
1257 mem = GST_BUFFER_MEM_PTR (buffer, i);
1258 s = gst_memory_get_sizes (mem, &o, &ms);
1262 /* first size, take accumulated data before as the offset */
1266 /* save the amount of data after this block */
1267 extra = ms - (o + s);
1269 /* empty block, add as extra */
1276 *maxsize = offs + size + extra;
1282 * gst_buffer_resize:
1283 * @buffer: a #GstBuffer.
1284 * @offset: the offset adjustement
1285 * @size: the new size or -1 to just adjust the offset
1287 * Set the offset and total size of the memory blocks in @buffer.
1290 gst_buffer_resize (GstBuffer * buffer, gssize offset, gssize size)
1292 gst_buffer_resize_range (buffer, 0, -1, offset, size);
1296 * gst_buffer_set_size:
1297 * @buffer: a #GstBuffer.
1298 * @size: the new size
1300 * Set the total size of the memory blocks in @buffer.
1303 gst_buffer_set_size (GstBuffer * buffer, gssize size)
1305 gst_buffer_resize_range (buffer, 0, -1, 0, size);
1309 * gst_buffer_resize_range:
1310 * @buffer: a #GstBuffer.
1313 * @offset: the offset adjustement
1314 * @size: the new size or -1 to just adjust the offset
1316 * Set the total size of the @length memory blocks starting at @idx in
1319 * Returns: %TRUE if resizing succeeded, %FALSE otherwise.
1322 gst_buffer_resize_range (GstBuffer * buffer, guint idx, gint length,
1323 gssize offset, gssize size)
1326 gsize bsize, bufsize, bufoffs, bufmax;
1328 g_return_val_if_fail (gst_buffer_is_writable (buffer), FALSE);
1329 g_return_val_if_fail (size >= -1, FALSE);
1331 len = GST_BUFFER_MEM_LEN (buffer);
1332 g_return_val_if_fail ((len == 0 && idx == 0 && length == -1) ||
1333 (length == -1 && idx < len) || (length + idx <= len), FALSE);
1338 bufsize = gst_buffer_get_sizes_range (buffer, idx, length, &bufoffs, &bufmax);
1340 GST_CAT_LOG (GST_CAT_BUFFER, "trim %p %" G_GSSIZE_FORMAT "-%" G_GSSIZE_FORMAT
1341 " size:%" G_GSIZE_FORMAT " offs:%" G_GSIZE_FORMAT " max:%"
1342 G_GSIZE_FORMAT, buffer, offset, size, bufsize, bufoffs, bufmax);
1344 /* we can't go back further than the current offset or past the end of the
1346 g_return_val_if_fail ((offset < 0 && bufoffs >= -offset) || (offset >= 0
1347 && bufoffs + offset <= bufmax), FALSE);
1349 g_return_val_if_fail (bufsize >= offset, FALSE);
1350 size = bufsize - offset;
1352 g_return_val_if_fail (bufmax >= bufoffs + offset + size, FALSE);
1355 if (offset == 0 && size == bufsize)
1360 for (i = idx; i < end; i++) {
1364 mem = GST_BUFFER_MEM_PTR (buffer, i);
1365 bsize = gst_memory_get_sizes (mem, NULL, NULL);
1368 /* last buffer always gets resized to the remaining size */
1371 /* shrink buffers before the offset */
1372 else if ((gssize) bsize <= offset) {
1374 noffs = offset - bsize;
1377 /* clip other buffers */
1379 left = MIN (bsize - offset, size);
1381 if (offset != 0 || left != bsize) {
1382 if (gst_memory_is_writable (mem)) {
1383 gst_memory_resize (mem, offset, left);
1385 GstMemory *newmem = NULL;
1387 if (!GST_MEMORY_IS_NO_SHARE (mem))
1388 newmem = gst_memory_share (mem, offset, left);
1391 newmem = gst_memory_copy (mem, offset, left);
1396 gst_memory_lock (newmem, GST_LOCK_FLAG_EXCLUSIVE);
1397 GST_BUFFER_MEM_PTR (buffer, i) = newmem;
1398 gst_memory_unlock (mem, GST_LOCK_FLAG_EXCLUSIVE);
1399 gst_memory_unref (mem);
1412 * @buffer: a #GstBuffer.
1413 * @info: (out): info about the mapping
1414 * @flags: flags for the mapping
1416 * This function fills @info with the #GstMapInfo of all merged memory
1417 * blocks in @buffer.
1419 * @flags describe the desired access of the memory. When @flags is
1420 * #GST_MAP_WRITE, @buffer should be writable (as returned from
1421 * gst_buffer_is_writable()).
1423 * When @buffer is writable but the memory isn't, a writable copy will
1424 * automatically be created and returned. The readonly copy of the
1425 * buffer memory will then also be replaced with this writable copy.
1427 * The memory in @info should be unmapped with gst_buffer_unmap() after
1430 * Returns: %TRUE if the map succeeded and @info contains valid data.
1433 gst_buffer_map (GstBuffer * buffer, GstMapInfo * info, GstMapFlags flags)
1435 return gst_buffer_map_range (buffer, 0, -1, info, flags);
1439 * gst_buffer_map_range:
1440 * @buffer: a #GstBuffer.
1443 * @info: (out): info about the mapping
1444 * @flags: flags for the mapping
1446 * This function fills @info with the #GstMapInfo of @length merged memory blocks
1447 * starting at @idx in @buffer. When @length is -1, all memory blocks starting
1448 * from @idx are merged and mapped.
1450 * @flags describe the desired access of the memory. When @flags is
1451 * #GST_MAP_WRITE, @buffer should be writable (as returned from
1452 * gst_buffer_is_writable()).
1454 * When @buffer is writable but the memory isn't, a writable copy will
1455 * automatically be created and returned. The readonly copy of the buffer memory
1456 * will then also be replaced with this writable copy.
1458 * The memory in @info should be unmapped with gst_buffer_unmap() after usage.
1460 * Returns: %TRUE if the map succeeded and @info contains valid
1464 gst_buffer_map_range (GstBuffer * buffer, guint idx, gint length,
1465 GstMapInfo * info, GstMapFlags flags)
1467 GstMemory *mem, *nmem;
1468 gboolean write, writable;
1471 g_return_val_if_fail (GST_IS_BUFFER (buffer), FALSE);
1472 g_return_val_if_fail (info != NULL, FALSE);
1473 len = GST_BUFFER_MEM_LEN (buffer);
1474 g_return_val_if_fail ((len == 0 && idx == 0 && length == -1) ||
1475 (length == -1 && idx < len) || (length > 0
1476 && length + idx <= len), FALSE);
1478 GST_CAT_LOG (GST_CAT_BUFFER, "buffer %p, idx %u, length %d, flags %04x",
1479 buffer, idx, length, flags);
1481 write = (flags & GST_MAP_WRITE) != 0;
1482 writable = gst_buffer_is_writable (buffer);
1484 /* check if we can write when asked for write access */
1485 if (G_UNLIKELY (write && !writable))
1491 mem = _get_merged_memory (buffer, idx, length);
1492 if (G_UNLIKELY (mem == NULL))
1495 /* now try to map */
1496 nmem = gst_memory_make_mapped (mem, info, flags);
1497 if (G_UNLIKELY (nmem == NULL))
1500 /* if we merged or when the map returned a different memory, we try to replace
1501 * the memory in the buffer */
1502 if (G_UNLIKELY (length > 1 || nmem != mem)) {
1503 /* if the buffer is writable, replace the memory */
1505 _replace_memory (buffer, len, idx, length, gst_memory_ref (nmem));
1508 GST_CAT_DEBUG (GST_CAT_PERFORMANCE,
1509 "temporary mapping for memory %p in buffer %p", nmem, buffer);
1518 GST_WARNING_OBJECT (buffer, "write map requested on non-writable buffer");
1519 g_critical ("write map requested on non-writable buffer");
1524 /* empty buffer, we need to return NULL */
1525 GST_DEBUG_OBJECT (buffer, "can't get buffer memory");
1526 info->memory = NULL;
1534 GST_DEBUG_OBJECT (buffer, "cannot map memory");
1541 * @buffer: a #GstBuffer.
1542 * @info: a #GstMapInfo
1544 * Release the memory previously mapped with gst_buffer_map().
1547 gst_buffer_unmap (GstBuffer * buffer, GstMapInfo * info)
1549 g_return_if_fail (GST_IS_BUFFER (buffer));
1550 g_return_if_fail (info != NULL);
1552 /* we need to check for NULL, it is possible that we tried to map a buffer
1553 * without memory and we should be able to unmap that fine */
1554 if (G_LIKELY (info->memory)) {
1555 gst_memory_unmap (info->memory, info);
1556 gst_memory_unref (info->memory);
1562 * @buffer: a #GstBuffer.
1563 * @offset: the offset to fill
1564 * @src: (array length=size) (element-type guint8): the source address
1565 * @size: the size to fill
1567 * Copy @size bytes from @src to @buffer at @offset.
1569 * Returns: The amount of bytes copied. This value can be lower than @size
1570 * when @buffer did not contain enough data.
1573 gst_buffer_fill (GstBuffer * buffer, gsize offset, gconstpointer src,
1577 const guint8 *ptr = src;
1579 g_return_val_if_fail (GST_IS_BUFFER (buffer), 0);
1580 g_return_val_if_fail (gst_buffer_is_writable (buffer), 0);
1581 g_return_val_if_fail (src != NULL || size == 0, 0);
1583 GST_CAT_LOG (GST_CAT_BUFFER,
1584 "buffer %p, offset %" G_GSIZE_FORMAT ", size %" G_GSIZE_FORMAT, buffer,
1587 len = GST_BUFFER_MEM_LEN (buffer);
1590 for (i = 0; i < len && left > 0; i++) {
1595 mem = _get_mapped (buffer, i, &info, GST_MAP_WRITE);
1596 if (info.size > offset) {
1597 /* we have enough */
1598 tocopy = MIN (info.size - offset, left);
1599 memcpy ((guint8 *) info.data + offset, ptr, tocopy);
1604 /* offset past buffer, skip */
1605 offset -= info.size;
1607 gst_memory_unmap (mem, &info);
1613 * gst_buffer_extract:
1614 * @buffer: a #GstBuffer.
1615 * @offset: the offset to extract
1616 * @dest: the destination address
1617 * @size: the size to extract
1619 * Copy @size bytes starting from @offset in @buffer to @dest.
1621 * Returns: The amount of bytes extracted. This value can be lower than @size
1622 * when @buffer did not contain enough data.
1625 gst_buffer_extract (GstBuffer * buffer, gsize offset, gpointer dest, gsize size)
1630 g_return_val_if_fail (GST_IS_BUFFER (buffer), 0);
1631 g_return_val_if_fail (dest != NULL, 0);
1633 GST_CAT_LOG (GST_CAT_BUFFER,
1634 "buffer %p, offset %" G_GSIZE_FORMAT ", size %" G_GSIZE_FORMAT, buffer,
1637 len = GST_BUFFER_MEM_LEN (buffer);
1640 for (i = 0; i < len && left > 0; i++) {
1645 mem = _get_mapped (buffer, i, &info, GST_MAP_READ);
1646 if (info.size > offset) {
1647 /* we have enough */
1648 tocopy = MIN (info.size - offset, left);
1649 memcpy (ptr, (guint8 *) info.data + offset, tocopy);
1654 /* offset past buffer, skip */
1655 offset -= info.size;
1657 gst_memory_unmap (mem, &info);
1663 * gst_buffer_memcmp:
1664 * @buffer: a #GstBuffer.
1665 * @offset: the offset in @buffer
1666 * @mem: (array length=size) (element-type guint8): the memory to compare
1667 * @size: the size to compare
1669 * Compare @size bytes starting from @offset in @buffer with the memory in @mem.
1671 * Returns: 0 if the memory is equal.
1674 gst_buffer_memcmp (GstBuffer * buffer, gsize offset, gconstpointer mem,
1678 const guint8 *ptr = mem;
1681 g_return_val_if_fail (GST_IS_BUFFER (buffer), 0);
1682 g_return_val_if_fail (mem != NULL, 0);
1684 GST_CAT_LOG (GST_CAT_BUFFER,
1685 "buffer %p, offset %" G_GSIZE_FORMAT ", size %" G_GSIZE_FORMAT, buffer,
1688 if (G_UNLIKELY (gst_buffer_get_size (buffer) < offset + size))
1691 len = GST_BUFFER_MEM_LEN (buffer);
1693 for (i = 0; i < len && size > 0 && res == 0; i++) {
1698 mem = _get_mapped (buffer, i, &info, GST_MAP_READ);
1699 if (info.size > offset) {
1700 /* we have enough */
1701 tocmp = MIN (info.size - offset, size);
1702 res = memcmp (ptr, (guint8 *) info.data + offset, tocmp);
1707 /* offset past buffer, skip */
1708 offset -= info.size;
1710 gst_memory_unmap (mem, &info);
1716 * gst_buffer_memset:
1717 * @buffer: a #GstBuffer.
1718 * @offset: the offset in @buffer
1719 * @val: the value to set
1720 * @size: the size to set
1722 * Fill @buf with @size bytes with @val starting from @offset.
1724 * Returns: The amount of bytes filled. This value can be lower than @size
1725 * when @buffer did not contain enough data.
1728 gst_buffer_memset (GstBuffer * buffer, gsize offset, guint8 val, gsize size)
1732 g_return_val_if_fail (GST_IS_BUFFER (buffer), 0);
1733 g_return_val_if_fail (gst_buffer_is_writable (buffer), 0);
1735 GST_CAT_LOG (GST_CAT_BUFFER,
1736 "buffer %p, offset %" G_GSIZE_FORMAT ", val %02x, size %" G_GSIZE_FORMAT,
1737 buffer, offset, val, size);
1739 len = GST_BUFFER_MEM_LEN (buffer);
1742 for (i = 0; i < len && left > 0; i++) {
1747 mem = _get_mapped (buffer, i, &info, GST_MAP_WRITE);
1748 if (info.size > offset) {
1749 /* we have enough */
1750 toset = MIN (info.size - offset, left);
1751 memset ((guint8 *) info.data + offset, val, toset);
1755 /* offset past buffer, skip */
1756 offset -= info.size;
1758 gst_memory_unmap (mem, &info);
1764 * gst_buffer_copy_region:
1765 * @parent: a #GstBuffer.
1766 * @flags: the #GstBufferCopyFlags
1767 * @offset: the offset into parent #GstBuffer at which the new sub-buffer
1769 * @size: the size of the new #GstBuffer sub-buffer, in bytes.
1771 * Creates a sub-buffer from @parent at @offset and @size.
1772 * This sub-buffer uses the actual memory space of the parent buffer.
1773 * This function will copy the offset and timestamp fields when the
1774 * offset is 0. If not, they will be set to #GST_CLOCK_TIME_NONE and
1775 * #GST_BUFFER_OFFSET_NONE.
1776 * If @offset equals 0 and @size equals the total size of @buffer, the
1777 * duration and offset end fields are also copied. If not they will be set
1778 * to #GST_CLOCK_TIME_NONE and #GST_BUFFER_OFFSET_NONE.
1782 * Returns: (transfer full): the new #GstBuffer or NULL if the arguments were
1786 gst_buffer_copy_region (GstBuffer * buffer, GstBufferCopyFlags flags,
1787 gsize offset, gsize size)
1791 g_return_val_if_fail (buffer != NULL, NULL);
1793 /* create the new buffer */
1794 copy = gst_buffer_new ();
1796 GST_CAT_LOG (GST_CAT_BUFFER, "new region copy %p of %p %" G_GSIZE_FORMAT
1797 "-%" G_GSIZE_FORMAT, copy, buffer, offset, size);
1799 if (!gst_buffer_copy_into (copy, buffer, flags, offset, size))
1800 gst_buffer_replace (©, NULL);
1806 * gst_buffer_append:
1807 * @buf1: (transfer full): the first source #GstBuffer to append.
1808 * @buf2: (transfer full): the second source #GstBuffer to append.
1810 * Append all the memory from @buf2 to @buf1. The result buffer will contain a
1811 * concatenation of the memory of @buf1 and @buf2.
1813 * Returns: (transfer full): the new #GstBuffer that contains the memory
1814 * of the two source buffers.
1817 gst_buffer_append (GstBuffer * buf1, GstBuffer * buf2)
1819 return gst_buffer_append_region (buf1, buf2, 0, -1);
1823 * gst_buffer_append_region:
1824 * @buf1: (transfer full): the first source #GstBuffer to append.
1825 * @buf2: (transfer full): the second source #GstBuffer to append.
1826 * @offset: the offset in @buf2
1827 * @size: the size or -1 of @buf2
1829 * Append @size bytes at @offset from @buf2 to @buf1. The result buffer will
1830 * contain a concatenation of the memory of @buf1 and the requested region of
1833 * Returns: (transfer full): the new #GstBuffer that contains the memory
1834 * of the two source buffers.
1837 gst_buffer_append_region (GstBuffer * buf1, GstBuffer * buf2, gssize offset,
1842 g_return_val_if_fail (GST_IS_BUFFER (buf1), NULL);
1843 g_return_val_if_fail (GST_IS_BUFFER (buf2), NULL);
1845 buf1 = gst_buffer_make_writable (buf1);
1846 buf2 = gst_buffer_make_writable (buf2);
1848 gst_buffer_resize (buf2, offset, size);
1850 len = GST_BUFFER_MEM_LEN (buf2);
1851 for (i = 0; i < len; i++) {
1854 mem = GST_BUFFER_MEM_PTR (buf2, i);
1855 GST_BUFFER_MEM_PTR (buf2, i) = NULL;
1856 _memory_add (buf1, -1, mem, FALSE);
1859 GST_BUFFER_MEM_LEN (buf2) = 0;
1860 gst_buffer_unref (buf2);
1866 * gst_buffer_get_meta:
1867 * @buffer: a #GstBuffer
1868 * @api: the #GType of an API
1870 * Get the metadata for @api on buffer. When there is no such
1871 * metadata, NULL is returned.
1873 * Returns: (transfer none): the metadata for @api on @buffer.
1876 gst_buffer_get_meta (GstBuffer * buffer, GType api)
1879 GstMeta *result = NULL;
1881 g_return_val_if_fail (buffer != NULL, NULL);
1882 g_return_val_if_fail (api != 0, NULL);
1884 /* find GstMeta of the requested API */
1885 for (item = GST_BUFFER_META (buffer); item; item = item->next) {
1886 GstMeta *meta = &item->meta;
1887 if (meta->info->api == api) {
1896 * gst_buffer_add_meta:
1897 * @buffer: a #GstBuffer
1898 * @info: a #GstMetaInfo
1899 * @params: params for @info
1901 * Add metadata for @info to @buffer using the parameters in @params.
1903 * Returns: (transfer none): the metadata for the api in @info on @buffer.
1906 gst_buffer_add_meta (GstBuffer * buffer, const GstMetaInfo * info,
1910 GstMeta *result = NULL;
1913 g_return_val_if_fail (buffer != NULL, NULL);
1914 g_return_val_if_fail (info != NULL, NULL);
1915 g_return_val_if_fail (gst_buffer_is_writable (buffer), NULL);
1917 /* create a new slice */
1918 size = ITEM_SIZE (info);
1919 item = g_slice_alloc (size);
1920 result = &item->meta;
1921 result->info = info;
1922 result->flags = GST_META_FLAG_NONE;
1924 GST_CAT_DEBUG (GST_CAT_BUFFER,
1925 "alloc metadata %p (%s) of size %" G_GSIZE_FORMAT, result,
1926 g_type_name (info->type), info->size);
1928 /* call the init_func when needed */
1929 if (info->init_func)
1930 if (!info->init_func (result, params, buffer))
1933 /* and add to the list of metadata */
1934 item->next = GST_BUFFER_META (buffer);
1935 GST_BUFFER_META (buffer) = item;
1941 g_slice_free1 (size, item);
1947 * gst_buffer_remove_meta:
1948 * @buffer: a #GstBuffer
1951 * Remove the metadata for @meta on @buffer.
1953 * Returns: %TRUE if the metadata existed and was removed, %FALSE if no such
1954 * metadata was on @buffer.
1957 gst_buffer_remove_meta (GstBuffer * buffer, GstMeta * meta)
1959 GstMetaItem *walk, *prev;
1961 g_return_val_if_fail (buffer != NULL, FALSE);
1962 g_return_val_if_fail (meta != NULL, FALSE);
1963 g_return_val_if_fail (gst_buffer_is_writable (buffer), FALSE);
1964 g_return_val_if_fail (!GST_META_FLAG_IS_SET (meta, GST_META_FLAG_LOCKED),
1967 /* find the metadata and delete */
1968 prev = GST_BUFFER_META (buffer);
1969 for (walk = prev; walk; walk = walk->next) {
1970 GstMeta *m = &walk->meta;
1972 const GstMetaInfo *info = meta->info;
1974 /* remove from list */
1975 if (GST_BUFFER_META (buffer) == walk)
1976 GST_BUFFER_META (buffer) = walk->next;
1978 prev->next = walk->next;
1979 /* call free_func if any */
1980 if (info->free_func)
1981 info->free_func (m, buffer);
1983 /* and free the slice */
1984 g_slice_free1 (ITEM_SIZE (info), walk);
1989 return walk != NULL;
1993 * gst_buffer_iterate_meta:
1994 * @buffer: a #GstBuffer
1995 * @state: an opaque state pointer
1997 * Retrieve the next #GstMeta after @current. If @state points
1998 * to %NULL, the first metadata is returned.
2000 * @state will be updated with an opage state pointer
2002 * Returns: (transfer none): The next #GstMeta or %NULL when there are
2006 gst_buffer_iterate_meta (GstBuffer * buffer, gpointer * state)
2010 g_return_val_if_fail (buffer != NULL, NULL);
2011 g_return_val_if_fail (state != NULL, NULL);
2013 meta = (GstMetaItem **) state;
2015 /* state NULL, move to first item */
2016 *meta = GST_BUFFER_META (buffer);
2018 /* state !NULL, move to next item in list */
2019 *meta = (*meta)->next;
2022 return &(*meta)->meta;
2028 * gst_buffer_foreach_meta:
2029 * @buffer: a #GstBuffer
2030 * @func: (scope call): a #GstBufferForeachMetaFunc to call
2031 * @user_data: (closure): user data passed to @func
2033 * Call @func with @user_data for each meta in @buffer.
2035 * @func can modify the passed meta pointer or its contents. The return value
2036 * of @func define if this function returns or if the remaining metadata items
2037 * in the buffer should be skipped.
2039 * Returns: %FALSE when @func returned %FALSE for one of the metadata.
2042 gst_buffer_foreach_meta (GstBuffer * buffer, GstBufferForeachMetaFunc func,
2045 GstMetaItem *walk, *prev, *next;
2046 gboolean res = TRUE;
2048 g_return_val_if_fail (buffer != NULL, FALSE);
2049 g_return_val_if_fail (func != NULL, FALSE);
2051 /* find the metadata and delete */
2052 prev = GST_BUFFER_META (buffer);
2053 for (walk = prev; walk; walk = next) {
2056 m = new = &walk->meta;
2059 res = func (buffer, &new, user_data);
2062 const GstMetaInfo *info = m->info;
2064 GST_CAT_DEBUG (GST_CAT_BUFFER, "remove metadata %p (%s)", m,
2065 g_type_name (info->type));
2067 g_return_val_if_fail (gst_buffer_is_writable (buffer), FALSE);
2068 g_return_val_if_fail (!GST_META_FLAG_IS_SET (m, GST_META_FLAG_LOCKED),
2071 /* remove from list */
2072 if (GST_BUFFER_META (buffer) == walk)
2073 GST_BUFFER_META (buffer) = next;
2077 /* call free_func if any */
2078 if (info->free_func)
2079 info->free_func (m, buffer);
2081 /* and free the slice */
2082 g_slice_free1 (ITEM_SIZE (info), walk);
2091 * gst_buffer_extract_dup:
2092 * @buffer: a #GstBuffer
2093 * @offset: the offset to extract
2094 * @size: the size to extract
2095 * @dest: (array length=dest_size) (element-type guint8) (out): A pointer where
2096 * the destination array will be written.
2097 * @dest_size: (out): A location where the size of @dest can be written
2099 * Extracts a copy of at most @size bytes the data at @offset into a #GBytes.
2100 * @dest must be freed using g_free() when done.
2106 gst_buffer_extract_dup (GstBuffer * buffer, gsize offset, gsize size,
2107 gpointer * dest, gsize * dest_size)
2111 real_size = gst_buffer_get_size (buffer);
2113 *dest = g_malloc (MIN (real_size - offset, size));
2115 *dest_size = gst_buffer_extract (buffer, offset, *dest, size);