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., 59 Temple Place - Suite 330,
20 * Boston, MA 02111-1307, 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 #GstBufferFlag 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;
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_size (buffer);
221 if (G_UNLIKELY (_is_span (mem + idx, length, &poffset, &parent))) {
222 if (GST_MEMORY_IS_NO_SHARE (parent)) {
223 GST_CAT_DEBUG (GST_CAT_PERFORMANCE, "copy for merge %p", parent);
224 result = gst_memory_copy (parent, poffset, size);
226 result = gst_memory_share (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 < 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 g_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_copy_into:
335 * @dest: a destination #GstBuffer
336 * @src: a source #GstBuffer
337 * @flags: flags indicating what metadata fields should be copied.
338 * @offset: offset to copy from
339 * @size: total size to copy. If -1, all data is copied.
341 * Copies the information from @src into @dest.
343 * If @dest already contains memory and @flags contains GST_BUFFER_COPY_MEMORY,
344 * the memory from @src will be appended to @dest.
346 * @flags indicate which fields will be copied.
349 gst_buffer_copy_into (GstBuffer * dest, GstBuffer * src,
350 GstBufferCopyFlags flags, gsize offset, gsize size)
354 gboolean region = FALSE;
356 g_return_if_fail (dest != NULL);
357 g_return_if_fail (src != NULL);
359 /* nothing to copy if the buffers are the same */
360 if (G_UNLIKELY (dest == src))
363 g_return_if_fail (gst_buffer_is_writable (dest));
365 bufsize = gst_buffer_get_size (src);
366 g_return_if_fail (bufsize >= offset);
370 size = bufsize - offset;
373 g_return_if_fail (bufsize >= offset + size);
375 GST_CAT_LOG (GST_CAT_BUFFER, "copy %p to %p, offset %" G_GSIZE_FORMAT
376 "-%" G_GSIZE_FORMAT "/%" G_GSIZE_FORMAT, src, dest, offset, size,
379 if (flags & GST_BUFFER_COPY_FLAGS) {
381 GST_MINI_OBJECT_FLAGS (dest) = GST_MINI_OBJECT_FLAGS (src);
384 if (flags & GST_BUFFER_COPY_TIMESTAMPS) {
386 GST_BUFFER_PTS (dest) = GST_BUFFER_PTS (src);
387 GST_BUFFER_DTS (dest) = GST_BUFFER_DTS (src);
388 GST_BUFFER_OFFSET (dest) = GST_BUFFER_OFFSET (src);
389 if (size == bufsize) {
390 GST_BUFFER_DURATION (dest) = GST_BUFFER_DURATION (src);
391 GST_BUFFER_OFFSET_END (dest) = GST_BUFFER_OFFSET_END (src);
394 GST_BUFFER_PTS (dest) = GST_CLOCK_TIME_NONE;
395 GST_BUFFER_DTS (dest) = GST_CLOCK_TIME_NONE;
396 GST_BUFFER_DURATION (dest) = GST_CLOCK_TIME_NONE;
397 GST_BUFFER_OFFSET (dest) = GST_BUFFER_OFFSET_NONE;
398 GST_BUFFER_OFFSET_END (dest) = GST_BUFFER_OFFSET_NONE;
402 if (flags & GST_BUFFER_COPY_MEMORY) {
404 gsize skip, left, len, i, bsize;
406 len = GST_BUFFER_MEM_LEN (src);
410 /* copy and make regions of the memory */
411 for (i = 0; i < len && left > 0; i++) {
412 mem = GST_BUFFER_MEM_PTR (src, i);
413 bsize = gst_memory_get_sizes (mem, NULL, NULL);
416 /* don't copy buffer */
421 tocopy = MIN (bsize - skip, left);
422 if (GST_MEMORY_IS_NO_SHARE (mem)) {
423 /* no share, always copy then */
424 mem = gst_memory_copy (mem, skip, tocopy);
426 } else if (tocopy < bsize) {
427 /* we need to clip something */
428 mem = gst_memory_share (mem, skip, tocopy);
431 mem = gst_memory_ref (mem);
433 _memory_add (dest, -1, mem, TRUE);
437 if (flags & GST_BUFFER_COPY_MERGE) {
438 len = GST_BUFFER_MEM_LEN (dest);
439 _replace_memory (dest, len, 0, len, _get_merged_memory (dest, 0, len));
443 if (flags & GST_BUFFER_COPY_META) {
444 for (walk = GST_BUFFER_META (src); walk; walk = walk->next) {
445 GstMeta *meta = &walk->meta;
446 const GstMetaInfo *info = meta->info;
448 if (info->transform_func) {
449 GstMetaTransformCopy copy_data;
451 copy_data.region = region;
452 copy_data.offset = offset;
453 copy_data.size = size;
455 info->transform_func (dest, meta, src,
456 _gst_meta_transform_copy, ©_data);
463 _gst_buffer_copy (GstBuffer * buffer)
467 g_return_val_if_fail (buffer != NULL, NULL);
469 /* create a fresh new buffer */
470 copy = gst_buffer_new ();
472 /* we simply copy everything from our parent */
473 gst_buffer_copy_into (copy, buffer, GST_BUFFER_COPY_ALL, 0, -1);
478 /* the default dispose function revives the buffer and returns it to the
479 * pool when there is a pool */
481 _gst_buffer_dispose (GstBuffer * buffer)
485 /* no pool, do free */
486 if ((pool = buffer->pool) == NULL)
489 /* keep the buffer alive */
490 gst_buffer_ref (buffer);
491 /* return the buffer to the pool */
492 GST_CAT_LOG (GST_CAT_BUFFER, "release %p to pool %p", buffer, pool);
493 gst_buffer_pool_release_buffer (pool, buffer);
499 _gst_buffer_free (GstBuffer * buffer)
501 GstMetaItem *walk, *next;
505 g_return_if_fail (buffer != NULL);
507 GST_CAT_LOG (GST_CAT_BUFFER, "finalize %p", buffer);
510 for (walk = GST_BUFFER_META (buffer); walk; walk = next) {
511 GstMeta *meta = &walk->meta;
512 const GstMetaInfo *info = meta->info;
514 /* call free_func if any */
516 info->free_func (meta, buffer);
519 /* and free the slice */
520 g_slice_free1 (ITEM_SIZE (info), walk);
523 /* get the size, when unreffing the memory, we could also unref the buffer
525 msize = GST_BUFFER_SLICE_SIZE (buffer);
527 /* free our memory */
528 len = GST_BUFFER_MEM_LEN (buffer);
529 for (i = 0; i < len; i++) {
530 gst_memory_unlock (GST_BUFFER_MEM_PTR (buffer, i), GST_LOCK_FLAG_EXCLUSIVE);
531 gst_memory_unref (GST_BUFFER_MEM_PTR (buffer, i));
534 /* we set msize to 0 when the buffer is part of the memory block */
537 memset (buffer, 0xff, msize);
539 g_slice_free1 (msize, buffer);
541 gst_memory_unref (GST_BUFFER_BUFMEM (buffer));
546 gst_buffer_init (GstBufferImpl * buffer, gsize size)
548 gst_mini_object_init (GST_MINI_OBJECT_CAST (buffer), 0, _gst_buffer_type,
549 (GstMiniObjectCopyFunction) _gst_buffer_copy,
550 (GstMiniObjectDisposeFunction) _gst_buffer_dispose,
551 (GstMiniObjectFreeFunction) _gst_buffer_free);
553 GST_BUFFER_SLICE_SIZE (buffer) = size;
555 GST_BUFFER (buffer)->pool = NULL;
556 GST_BUFFER_PTS (buffer) = GST_CLOCK_TIME_NONE;
557 GST_BUFFER_DTS (buffer) = GST_CLOCK_TIME_NONE;
558 GST_BUFFER_DURATION (buffer) = GST_CLOCK_TIME_NONE;
559 GST_BUFFER_OFFSET (buffer) = GST_BUFFER_OFFSET_NONE;
560 GST_BUFFER_OFFSET_END (buffer) = GST_BUFFER_OFFSET_NONE;
562 GST_BUFFER_MEM_LEN (buffer) = 0;
563 GST_BUFFER_META (buffer) = NULL;
569 * Creates a newly allocated buffer without any data.
573 * Returns: (transfer full): the new #GstBuffer.
576 gst_buffer_new (void)
578 GstBufferImpl *newbuf;
580 newbuf = g_slice_new (GstBufferImpl);
581 GST_CAT_LOG (GST_CAT_BUFFER, "new %p", newbuf);
583 gst_buffer_init (newbuf, sizeof (GstBufferImpl));
585 return GST_BUFFER_CAST (newbuf);
589 * gst_buffer_new_allocate:
590 * @allocator: (transfer none) (allow-none): the #GstAllocator to use, or NULL to use the
592 * @size: the size in bytes of the new buffer's data.
593 * @params: (transfer none) (allow-none): optional parameters
595 * Tries to create a newly allocated buffer with data of the given size and
596 * extra parameters from @allocator. If the requested amount of memory can't be
597 * allocated, NULL will be returned. The allocated buffer memory is not cleared.
599 * When @allocator is NULL, the default memory allocator will be used.
601 * Note that when @size == 0, the buffer will not have memory associated with it.
605 * Returns: (transfer full): a new #GstBuffer, or NULL if the memory couldn't
609 gst_buffer_new_allocate (GstAllocator * allocator, gsize size,
610 GstAllocationParams * params)
621 mem = gst_allocator_alloc (allocator, size, params);
622 if (G_UNLIKELY (mem == NULL))
628 newbuf = gst_buffer_new ();
631 _memory_add (newbuf, -1, mem, TRUE);
633 GST_CAT_LOG (GST_CAT_BUFFER,
634 "new buffer %p of size %" G_GSIZE_FORMAT " from allocator %p", newbuf,
639 asize = sizeof (GstBufferImpl) + size;
640 data = g_slice_alloc (asize);
641 if (G_UNLIKELY (data == NULL))
644 newbuf = GST_BUFFER_CAST (data);
646 gst_buffer_init ((GstBufferImpl *) data, asize);
648 mem = gst_memory_new_wrapped (0, data + sizeof (GstBufferImpl), NULL,
650 _memory_add (newbuf, -1, mem, TRUE);
655 /* allocate memory and buffer, it might be interesting to do this but there
656 * are many complications. We need to keep the memory mapped to access the
657 * buffer fields and the memory for the buffer might be just very slow. We
658 * also need to do some more magic to get the alignment right. */
659 asize = sizeof (GstBufferImpl) + size;
660 mem = gst_allocator_alloc (allocator, asize, align);
661 if (G_UNLIKELY (mem == NULL))
664 /* map the data part and init the buffer in it, set the buffer size to 0 so
665 * that a finalize won't free the buffer */
666 data = gst_memory_map (mem, &asize, NULL, GST_MAP_WRITE);
667 gst_buffer_init ((GstBufferImpl *) data, 0);
668 gst_memory_unmap (mem);
670 /* strip off the buffer */
671 gst_memory_resize (mem, sizeof (GstBufferImpl), size);
673 newbuf = GST_BUFFER_CAST (data);
674 GST_BUFFER_BUFMEM (newbuf) = mem;
677 _memory_add (newbuf, -1, gst_memory_ref (mem), TRUE);
685 GST_CAT_WARNING (GST_CAT_BUFFER,
686 "failed to allocate %" G_GSIZE_FORMAT " bytes", size);
692 * gst_buffer_new_wrapped_full:
693 * @flags: #GstMemoryFlags
694 * @data: data to wrap
695 * @maxsize: allocated size of @data
696 * @offset: offset in @data
697 * @size: size of valid data
698 * @user_data: user_data
699 * @notify: called with @user_data when the memory is freed
701 * Allocate a new buffer that wraps the given memory. @data must point to
702 * @maxsize of memory, the wrapped buffer will have the region from @offset and
705 * When the buffer is destroyed, @notify will be called with @user_data.
707 * The prefix/padding must be filled with 0 if @flags contains
708 * #GST_MEMORY_FLAG_ZERO_PREFIXED and #GST_MEMORY_FLAG_ZERO_PADDED respectively.
710 * Returns: (transfer full): a new #GstBuffer
713 gst_buffer_new_wrapped_full (GstMemoryFlags flags, gpointer data,
714 gsize maxsize, gsize offset, gsize size, gpointer user_data,
715 GDestroyNotify notify)
719 newbuf = gst_buffer_new ();
720 gst_buffer_append_memory (newbuf,
721 gst_memory_new_wrapped (flags, data, maxsize, offset, size,
728 * gst_buffer_new_wrapped:
729 * @data: data to wrap
730 * @size: allocated size of @data
732 * Creates a new buffer that wraps the given @data. The memory will be freed
733 * with g_free and will be marked writable.
737 * Returns: (transfer full): a new #GstBuffer
740 gst_buffer_new_wrapped (gpointer data, gsize size)
742 return gst_buffer_new_wrapped_full (0, data, size, 0, size, data, g_free);
746 * gst_buffer_n_memory:
747 * @buffer: a #GstBuffer.
749 * Get the amount of memory blocks that this buffer has.
751 * Returns: (transfer full): the amount of memory block in this buffer.
754 gst_buffer_n_memory (GstBuffer * buffer)
756 g_return_val_if_fail (GST_IS_BUFFER (buffer), 0);
758 return GST_BUFFER_MEM_LEN (buffer);
762 * gst_buffer_prepend_memory:
764 * @m: (transfer full): a #GstMemory.
766 * Prepend the memory block @m to @b. This function takes ownership
767 * of @m and thus doesn't increase its refcount.
770 * gst_buffer_append_memory:
772 * @m: (transfer full): a #GstMemory.
774 * Append the memory block @m to @b. This function takes ownership
775 * of @m and thus doesn't increase its refcount.
778 * gst_buffer_insert_memory:
779 * @buffer: a #GstBuffer.
780 * @idx: the index to add the memory at, or -1 to append it to the end
781 * @mem: (transfer full): a #GstMemory.
783 * Insert the memory block @mem to @buffer at @idx. This function takes ownership
784 * of @mem and thus doesn't increase its refcount.
787 gst_buffer_insert_memory (GstBuffer * buffer, gint idx, GstMemory * mem)
789 g_return_if_fail (GST_IS_BUFFER (buffer));
790 g_return_if_fail (gst_buffer_is_writable (buffer));
791 g_return_if_fail (mem != NULL);
792 g_return_if_fail (idx == -1 ||
793 (idx >= 0 && idx <= GST_BUFFER_MEM_LEN (buffer)));
795 _memory_add (buffer, idx, mem, TRUE);
799 _get_mapped (GstBuffer * buffer, guint idx, GstMapInfo * info,
802 GstMemory *mem, *mapped;
804 mem = gst_memory_ref (GST_BUFFER_MEM_PTR (buffer, idx));
806 mapped = gst_memory_make_mapped (mem, info, flags);
809 /* memory changed, lock new memory */
810 gst_memory_lock (mapped, GST_LOCK_FLAG_EXCLUSIVE);
811 GST_BUFFER_MEM_PTR (buffer, idx) = mapped;
812 /* unlock old memory */
813 gst_memory_unlock (mem, GST_LOCK_FLAG_EXCLUSIVE);
815 gst_memory_unref (mem);
821 * gst_buffer_peek_memory:
822 * @buffer: a #GstBuffer.
825 * Get the memory block at @idx in @buffer. The memory block stays valid until
826 * the memory block in @buffer is removed, replaced or merged, typically with
827 * any call that modifies the memory in @buffer.
829 * Since this call does not influence the refcount of the memory,
830 * gst_memory_is_writable() can be used to check if @buffer is the sole owner
831 * of the returned memory.
833 * Returns: (transfer none): the #GstMemory at @idx.
836 gst_buffer_peek_memory (GstBuffer * buffer, guint idx)
840 g_return_val_if_fail (GST_IS_BUFFER (buffer), NULL);
841 len = GST_BUFFER_MEM_LEN (buffer);
842 g_return_val_if_fail (idx < len, NULL);
844 return GST_BUFFER_MEM_PTR (buffer, idx);
848 * gst_buffer_get_memory:
852 * Get the memory block at index @i in @buffer.
854 * Returns: (transfer full): a #GstMemory that contains the data of the
855 * memory block at @idx. Use gst_memory_unref () after usage.
858 * gst_buffer_get_all_memory:
861 * Get all the memory block in @buffer. The memory blocks will be merged
862 * into one large #GstMemory.
864 * Returns: (transfer full): a #GstMemory that contains the merged memory.
865 * Use gst_memory_unref () after usage.
868 * gst_buffer_get_memory_range:
869 * @buffer: a #GstBuffer.
873 * Get @length memory blocks in @buffer starting at @idx. The memory blocks will
874 * be merged into one large #GstMemory.
876 * If @length is -1, all memory starting from @idx is merged.
878 * Returns: (transfer full): a #GstMemory that contains the merged data of @length
879 * blocks starting at @idx. Use gst_memory_unref () after usage.
882 gst_buffer_get_memory_range (GstBuffer * buffer, guint idx, gint length)
886 GST_CAT_DEBUG (GST_CAT_BUFFER, "idx %u, length %d", idx, length);
888 g_return_val_if_fail (GST_IS_BUFFER (buffer), NULL);
889 len = GST_BUFFER_MEM_LEN (buffer);
890 g_return_val_if_fail ((len == 0 && idx == 0 && length == -1) ||
891 (length == -1 && idx < len) || (length > 0 && length + idx <= len), NULL);
896 return _get_merged_memory (buffer, idx, length);
900 * gst_buffer_replace_memory:
903 * @m: (transfer full): a #GstMemory
905 * Replaces the memory block at index @i in @b with @m.
908 * gst_buffer_replace_all_memory:
910 * @m: (transfer full): a #GstMemory
912 * Replaces all memory in @b with @m.
915 * gst_buffer_replace_memory_range:
916 * @buffer: a #GstBuffer.
918 * @length: a length should not be 0
919 * @mem: (transfer full): a #GstMemory
921 * Replaces @length memory blocks in @buffer starting at @idx with @mem.
923 * If @length is -1, all memory starting from @idx will be removed and
924 * replaced with @mem.
926 * @buffer should be writable.
929 gst_buffer_replace_memory_range (GstBuffer * buffer, guint idx, gint length,
934 g_return_if_fail (GST_IS_BUFFER (buffer));
935 g_return_if_fail (gst_buffer_is_writable (buffer));
937 GST_CAT_DEBUG (GST_CAT_BUFFER, "idx %u, length %d, %p", idx, length, mem);
939 len = GST_BUFFER_MEM_LEN (buffer);
940 g_return_if_fail ((len == 0 && idx == 0 && length == -1) ||
941 (length == -1 && idx < len) || (length > 0 && length + idx <= len));
946 _replace_memory (buffer, len, idx, length, mem);
950 * gst_buffer_remove_memory:
954 * Remove the memory block in @b at index @i.
957 * gst_buffer_remove_all_memory:
960 * Remove all the memory blocks in @b.
963 * gst_buffer_remove_memory_range:
964 * @buffer: a #GstBuffer.
968 * Remove @length memory blocks in @buffer starting from @idx.
970 * @length can be -1, in which case all memory starting from @idx is removed.
973 gst_buffer_remove_memory_range (GstBuffer * buffer, guint idx, gint length)
977 g_return_if_fail (GST_IS_BUFFER (buffer));
978 g_return_if_fail (gst_buffer_is_writable (buffer));
980 GST_CAT_DEBUG (GST_CAT_BUFFER, "idx %u, length %d", idx, length);
982 len = GST_BUFFER_MEM_LEN (buffer);
983 g_return_if_fail ((len == 0 && idx == 0 && length == -1) ||
984 (length == -1 && idx < len) || length + idx <= len);
989 _replace_memory (buffer, len, idx, length, NULL);
993 * gst_buffer_find_memory:
994 * @buffer: a #GstBuffer.
997 * @idx: (out): pointer to index
998 * @length: (out): pointer to length
999 * @skip: (out): pointer to skip
1001 * Find the memory blocks that span @size bytes starting from @offset
1004 * When this function returns %TRUE, @idx will contain the index of the first
1005 * memory bock where the byte for @offset can be found and @length contains the
1006 * number of memory blocks containing the @size remaining bytes. @skip contains
1007 * the number of bytes to skip in the memory bock at @idx to get to the byte
1010 * @size can be -1 to get all the memory blocks after @idx.
1012 * Returns: %TRUE when @size bytes starting from @offset could be found in
1013 * @buffer and @idx, @length and @skip will be filled.
1016 gst_buffer_find_memory (GstBuffer * buffer, gsize offset, gsize size,
1017 guint * idx, guint * length, gsize * skip)
1019 guint i, len, found;
1021 g_return_val_if_fail (GST_IS_BUFFER (buffer), FALSE);
1022 g_return_val_if_fail (idx != NULL, FALSE);
1023 g_return_val_if_fail (length != NULL, FALSE);
1024 g_return_val_if_fail (skip != NULL, FALSE);
1026 len = GST_BUFFER_MEM_LEN (buffer);
1029 for (i = 0; i < len; i++) {
1033 mem = GST_BUFFER_MEM_PTR (buffer, i);
1034 s = gst_memory_get_sizes (mem, NULL, NULL);
1037 /* block before offset, or empty block, skip */
1040 /* block after offset */
1042 /* first block, remember index and offset */
1046 /* return remaining blocks */
1053 /* count the amount of found bytes */
1055 if (found >= size) {
1056 /* we have enough bytes */
1057 *length = i - *idx + 1;
1066 * gst_buffer_get_sizes:
1068 * @of: (out): a pointer to the offset
1069 * @ms: (out): a pointer to the maxsize
1071 * Get the total size of the memory blocks in @b.
1073 * When not %NULL, @of will contain the offset of the data in the first
1074 * memory block in @buffer and @maxsize will contain the sum of the size
1075 * and @of and the amount of extra padding on the last memory block.
1076 * @of and @ms can be used to resize the buffer memory blocks with
1077 * gst_buffer_resize().
1079 * Returns: total size of the memory blocks in @b.
1082 * gst_buffer_get_size:
1085 * Get the total size of the memory blocks in @b.
1087 * Returns: total size of the memory blocks in @b.
1090 * gst_buffer_get_sizes_range:
1091 * @buffer: a #GstBuffer.
1094 * @offset: (out): a pointer to the offset
1095 * @maxsize: (out): a pointer to the maxsize
1097 * Get the total size of @length memory blocks stating from @idx in @buffer.
1099 * When not %NULL, @offset will contain the offset of the data in the
1100 * memory block in @buffer at @idx and @maxsize will contain the sum of the size
1101 * and @offset and the amount of extra padding on the memory block at @idx +
1103 * @offset and @maxsize can be used to resize the buffer memory blocks with
1104 * gst_buffer_resize_range().
1106 * Returns: total size of @length memory blocks starting at @idx in @buffer.
1109 gst_buffer_get_sizes_range (GstBuffer * buffer, guint idx, gint length,
1110 gsize * offset, gsize * maxsize)
1116 g_return_val_if_fail (GST_IS_BUFFER (buffer), 0);
1117 len = GST_BUFFER_MEM_LEN (buffer);
1118 g_return_val_if_fail ((len == 0 && idx == 0 && length == -1) ||
1119 (length == -1 && idx < len) || (length + idx <= len), 0);
1124 if (G_LIKELY (length == 1)) {
1126 mem = GST_BUFFER_MEM_PTR (buffer, idx);
1127 size = gst_memory_get_sizes (mem, offset, maxsize);
1133 size = offs = extra = 0;
1134 for (i = idx; i < end; i++) {
1137 mem = GST_BUFFER_MEM_PTR (buffer, i);
1138 s = gst_memory_get_sizes (mem, &o, &ms);
1142 /* first size, take accumulated data before as the offset */
1146 /* save the amount of data after this block */
1147 extra = ms - (o + s);
1149 /* empty block, add as extra */
1156 *maxsize = offs + size + extra;
1162 * gst_buffer_resize:
1164 * @of: the offset adjustement
1165 * @s: the new size or -1 to just adjust the offset
1167 * Set the offset and total size of the memory blocks in @b.
1170 * gst_buffer_set_size:
1174 * Set the total size of the memory blocks in @b.
1177 * gst_buffer_resize_range:
1178 * @buffer: a #GstBuffer.
1181 * @offset: the offset adjustement
1182 * @size: the new size or -1 to just adjust the offset
1184 * Set the total size of the @length memory blocks starting at @idx in
1188 gst_buffer_resize_range (GstBuffer * buffer, guint idx, gint length,
1189 gssize offset, gssize size)
1192 gsize bsize, bufsize, bufoffs, bufmax;
1194 g_return_if_fail (gst_buffer_is_writable (buffer));
1195 g_return_if_fail (size >= -1);
1196 len = GST_BUFFER_MEM_LEN (buffer);
1197 g_return_if_fail ((len == 0 && idx == 0 && length == -1) ||
1198 (length == -1 && idx < len) || (length + idx <= len));
1203 bufsize = gst_buffer_get_sizes_range (buffer, idx, length, &bufoffs, &bufmax);
1205 GST_CAT_LOG (GST_CAT_BUFFER, "trim %p %" G_GSSIZE_FORMAT "-%" G_GSSIZE_FORMAT
1206 " size:%" G_GSIZE_FORMAT " offs:%" G_GSIZE_FORMAT " max:%"
1207 G_GSIZE_FORMAT, buffer, offset, size, bufsize, bufoffs, bufmax);
1209 /* we can't go back further than the current offset or past the end of the
1211 g_return_if_fail ((offset < 0 && bufoffs >= -offset) || (offset >= 0
1212 && bufoffs + offset <= bufmax));
1214 g_return_if_fail (bufsize >= offset);
1215 size = bufsize - offset;
1217 g_return_if_fail (bufmax >= bufoffs + offset + size);
1220 if (offset == 0 && size == bufsize)
1225 for (i = idx; i < end; i++) {
1229 mem = GST_BUFFER_MEM_PTR (buffer, i);
1230 bsize = gst_memory_get_sizes (mem, NULL, NULL);
1233 /* last buffer always gets resized to the remaining size */
1236 /* shrink buffers before the offset */
1237 else if ((gssize) bsize <= offset) {
1239 noffs = offset - bsize;
1242 /* clip other buffers */
1244 left = MIN (bsize - offset, size);
1246 if (offset != 0 || left != bsize) {
1247 if (gst_memory_is_writable (mem)) {
1248 gst_memory_resize (mem, offset, left);
1252 if (GST_MEMORY_IS_NO_SHARE (mem))
1253 newmem = gst_memory_copy (mem, offset, left);
1255 newmem = gst_memory_share (mem, offset, left);
1257 gst_memory_lock (newmem, GST_LOCK_FLAG_EXCLUSIVE);
1258 GST_BUFFER_MEM_PTR (buffer, i) = newmem;
1259 gst_memory_unlock (mem, GST_LOCK_FLAG_EXCLUSIVE);
1260 gst_memory_unref (mem);
1272 * @i: (out): info about the mapping
1273 * @f: flags for the mapping
1275 * This function fills @i with the #GstMapInfo of all merged memory blocks
1278 * @flags describe the desired access of the memory. When @flags is
1279 * #GST_MAP_WRITE, @buffer should be writable (as returned from
1280 * gst_buffer_is_writable()).
1282 * When @buffer is writable but the memory isn't, a writable copy will
1283 * automatically be created and returned. The readonly copy of the buffer memory
1284 * will then also be replaced with this writable copy.
1286 * The memory in @i should be unmapped with gst_buffer_unmap() after usage.
1288 * Returns: %TRUE if the map succeeded and @i contains valid data.
1291 * gst_buffer_map_range:
1292 * @buffer: a #GstBuffer.
1295 * @info: (out): info about the mapping
1296 * @flags: flags for the mapping
1298 * This function fills @info with the #GstMapInfo of @length merged memory blocks
1299 * starting at @idx in @buffer. When @length is -1, all memory blocks starting
1300 * from @idx are merged and mapped.
1302 * @flags describe the desired access of the memory. When @flags is
1303 * #GST_MAP_WRITE, @buffer should be writable (as returned from
1304 * gst_buffer_is_writable()).
1306 * When @buffer is writable but the memory isn't, a writable copy will
1307 * automatically be created and returned. The readonly copy of the buffer memory
1308 * will then also be replaced with this writable copy.
1310 * The memory in @info should be unmapped with gst_buffer_unmap() after usage.
1312 * Returns: %TRUE if the map succeeded and @info contains valid
1316 gst_buffer_map_range (GstBuffer * buffer, guint idx, gint length,
1317 GstMapInfo * info, GstMapFlags flags)
1319 GstMemory *mem, *nmem;
1320 gboolean write, writable;
1323 g_return_val_if_fail (GST_IS_BUFFER (buffer), FALSE);
1324 g_return_val_if_fail (info != NULL, FALSE);
1325 len = GST_BUFFER_MEM_LEN (buffer);
1326 g_return_val_if_fail ((len == 0 && idx == 0 && length == -1) ||
1327 (length == -1 && idx < len) || (length > 0
1328 && length + idx <= len), FALSE);
1330 GST_CAT_LOG (GST_CAT_BUFFER, "buffer %p, idx %u, length %d, flags %04x",
1331 buffer, idx, length, flags);
1333 write = (flags & GST_MAP_WRITE) != 0;
1334 writable = gst_buffer_is_writable (buffer);
1336 /* check if we can write when asked for write access */
1337 if (G_UNLIKELY (write && !writable))
1343 mem = _get_merged_memory (buffer, idx, length);
1344 if (G_UNLIKELY (mem == NULL))
1347 /* now try to map */
1348 nmem = gst_memory_make_mapped (mem, info, flags);
1349 if (G_UNLIKELY (nmem == NULL))
1352 /* if we merged or when the map returned a different memory, we try to replace
1353 * the memory in the buffer */
1354 if (G_UNLIKELY (length > 1 || nmem != mem)) {
1355 /* if the buffer is writable, replace the memory */
1357 _replace_memory (buffer, len, idx, length, gst_memory_ref (nmem));
1360 GST_CAT_DEBUG (GST_CAT_PERFORMANCE,
1361 "temporary mapping for memory %p in buffer %p", nmem, buffer);
1370 GST_WARNING_OBJECT (buffer, "write map requested on non-writable buffer");
1371 g_critical ("write map requested on non-writable buffer");
1376 /* empty buffer, we need to return NULL */
1377 GST_DEBUG_OBJECT (buffer, "can't get buffer memory");
1378 info->memory = NULL;
1386 GST_DEBUG_OBJECT (buffer, "cannot map memory");
1393 * @buffer: a #GstBuffer.
1394 * @info: a #GstMapInfo
1396 * Release the memory previously mapped with gst_buffer_map().
1399 gst_buffer_unmap (GstBuffer * buffer, GstMapInfo * info)
1401 g_return_if_fail (GST_IS_BUFFER (buffer));
1402 g_return_if_fail (info != NULL);
1404 /* we need to check for NULL, it is possible that we tried to map a buffer
1405 * without memory and we should be able to unmap that fine */
1406 if (G_LIKELY (info->memory)) {
1407 gst_memory_unmap (info->memory, info);
1408 gst_memory_unref (info->memory);
1414 * @buffer: a #GstBuffer.
1415 * @offset: the offset to fill
1416 * @src: the source address
1417 * @size: the size to fill
1419 * Copy @size bytes from @src to @buffer at @offset.
1421 * Returns: The amount of bytes copied. This value can be lower than @size
1422 * when @buffer did not contain enough data.
1425 gst_buffer_fill (GstBuffer * buffer, gsize offset, gconstpointer src,
1429 const guint8 *ptr = src;
1431 g_return_val_if_fail (GST_IS_BUFFER (buffer), 0);
1432 g_return_val_if_fail (gst_buffer_is_writable (buffer), 0);
1433 g_return_val_if_fail (src != NULL, 0);
1435 GST_CAT_LOG (GST_CAT_BUFFER,
1436 "buffer %p, offset %" G_GSIZE_FORMAT ", size %" G_GSIZE_FORMAT, buffer,
1439 len = GST_BUFFER_MEM_LEN (buffer);
1442 for (i = 0; i < len && left > 0; i++) {
1447 mem = _get_mapped (buffer, i, &info, GST_MAP_WRITE);
1448 if (info.size > offset) {
1449 /* we have enough */
1450 tocopy = MIN (info.size - offset, left);
1451 memcpy ((guint8 *) info.data + offset, ptr, tocopy);
1456 /* offset past buffer, skip */
1457 offset -= info.size;
1459 gst_memory_unmap (mem, &info);
1465 * gst_buffer_extract:
1466 * @buffer: a #GstBuffer.
1467 * @offset: the offset to extract
1468 * @dest: the destination address
1469 * @size: the size to extract
1471 * Copy @size bytes starting from @offset in @buffer to @dest.
1473 * Returns: The amount of bytes extracted. This value can be lower than @size
1474 * when @buffer did not contain enough data.
1477 gst_buffer_extract (GstBuffer * buffer, gsize offset, gpointer dest, gsize size)
1482 g_return_val_if_fail (GST_IS_BUFFER (buffer), 0);
1483 g_return_val_if_fail (dest != NULL, 0);
1485 GST_CAT_LOG (GST_CAT_BUFFER,
1486 "buffer %p, offset %" G_GSIZE_FORMAT ", size %" G_GSIZE_FORMAT, buffer,
1489 len = GST_BUFFER_MEM_LEN (buffer);
1492 for (i = 0; i < len && left > 0; i++) {
1497 mem = _get_mapped (buffer, i, &info, GST_MAP_READ);
1498 if (info.size > offset) {
1499 /* we have enough */
1500 tocopy = MIN (info.size - offset, left);
1501 memcpy (ptr, (guint8 *) info.data + offset, tocopy);
1506 /* offset past buffer, skip */
1507 offset -= info.size;
1509 gst_memory_unmap (mem, &info);
1515 * gst_buffer_memcmp:
1516 * @buffer: a #GstBuffer.
1517 * @offset: the offset in @buffer
1518 * @mem: the memory to compare
1519 * @size: the size to compare
1521 * Compare @size bytes starting from @offset in @buffer with the memory in @mem.
1523 * Returns: 0 if the memory is equal.
1526 gst_buffer_memcmp (GstBuffer * buffer, gsize offset, gconstpointer mem,
1530 const guint8 *ptr = mem;
1533 g_return_val_if_fail (GST_IS_BUFFER (buffer), 0);
1534 g_return_val_if_fail (mem != NULL, 0);
1536 GST_CAT_LOG (GST_CAT_BUFFER,
1537 "buffer %p, offset %" G_GSIZE_FORMAT ", size %" G_GSIZE_FORMAT, buffer,
1540 len = GST_BUFFER_MEM_LEN (buffer);
1542 for (i = 0; i < len && size > 0 && res == 0; i++) {
1547 mem = _get_mapped (buffer, i, &info, GST_MAP_READ);
1548 if (info.size > offset) {
1549 /* we have enough */
1550 tocmp = MIN (info.size - offset, size);
1551 res = memcmp (ptr, (guint8 *) info.data + offset, tocmp);
1556 /* offset past buffer, skip */
1557 offset -= info.size;
1559 gst_memory_unmap (mem, &info);
1565 * gst_buffer_memset:
1566 * @buffer: a #GstBuffer.
1567 * @offset: the offset in @buffer
1568 * @val: the value to set
1569 * @size: the size to set
1571 * Fill @buf with @size bytes with @val starting from @offset.
1573 * Returns: The amount of bytes filled. This value can be lower than @size
1574 * when @buffer did not contain enough data.
1577 gst_buffer_memset (GstBuffer * buffer, gsize offset, guint8 val, gsize size)
1581 g_return_val_if_fail (GST_IS_BUFFER (buffer), 0);
1582 g_return_val_if_fail (gst_buffer_is_writable (buffer), 0);
1584 GST_CAT_LOG (GST_CAT_BUFFER,
1585 "buffer %p, offset %" G_GSIZE_FORMAT ", val %02x, size %" G_GSIZE_FORMAT,
1586 buffer, offset, val, size);
1588 len = GST_BUFFER_MEM_LEN (buffer);
1591 for (i = 0; i < len && left > 0; i++) {
1596 mem = _get_mapped (buffer, i, &info, GST_MAP_WRITE);
1597 if (info.size > offset) {
1598 /* we have enough */
1599 toset = MIN (info.size - offset, left);
1600 memset ((guint8 *) info.data + offset, val, toset);
1604 /* offset past buffer, skip */
1605 offset -= info.size;
1607 gst_memory_unmap (mem, &info);
1613 * gst_buffer_copy_region:
1614 * @parent: a #GstBuffer.
1615 * @flags: the #GstBufferCopyFlags
1616 * @offset: the offset into parent #GstBuffer at which the new sub-buffer
1618 * @size: the size of the new #GstBuffer sub-buffer, in bytes.
1620 * Creates a sub-buffer from @parent at @offset and @size.
1621 * This sub-buffer uses the actual memory space of the parent buffer.
1622 * This function will copy the offset and timestamp fields when the
1623 * offset is 0. If not, they will be set to #GST_CLOCK_TIME_NONE and
1624 * #GST_BUFFER_OFFSET_NONE.
1625 * If @offset equals 0 and @size equals the total size of @buffer, the
1626 * duration and offset end fields are also copied. If not they will be set
1627 * to #GST_CLOCK_TIME_NONE and #GST_BUFFER_OFFSET_NONE.
1631 * Returns: (transfer full): the new #GstBuffer or NULL if the arguments were
1635 gst_buffer_copy_region (GstBuffer * buffer, GstBufferCopyFlags flags,
1636 gsize offset, gsize size)
1640 g_return_val_if_fail (buffer != NULL, NULL);
1642 /* create the new buffer */
1643 copy = gst_buffer_new ();
1645 GST_CAT_LOG (GST_CAT_BUFFER, "new region copy %p of %p %" G_GSIZE_FORMAT
1646 "-%" G_GSIZE_FORMAT, copy, buffer, offset, size);
1648 gst_buffer_copy_into (copy, buffer, flags, offset, size);
1654 * gst_buffer_append:
1655 * @buf1: (transfer full): the first source #GstBuffer to append.
1656 * @buf2: (transfer full): the second source #GstBuffer to append.
1658 * Append all the memory from @buf2 to @buf1. The result buffer will contain a
1659 * concatenation of the memory of @buf1 and @buf2.
1661 * Returns: (transfer full): the new #GstBuffer that contains the memory
1662 * of the two source buffers.
1665 * gst_buffer_append_region:
1666 * @buf1: (transfer full): the first source #GstBuffer to append.
1667 * @buf2: (transfer full): the second source #GstBuffer to append.
1668 * @offset: the offset in @buf2
1669 * @size: the size or -1 of @buf2
1671 * Append @size bytes at @offset from @buf2 to @buf1. The result buffer will
1672 * contain a concatenation of the memory of @buf1 and the requested region of
1675 * Returns: (transfer full): the new #GstBuffer that contains the memory
1676 * of the two source buffers.
1679 gst_buffer_append_region (GstBuffer * buf1, GstBuffer * buf2, gssize offset,
1684 g_return_val_if_fail (GST_IS_BUFFER (buf1), NULL);
1685 g_return_val_if_fail (GST_IS_BUFFER (buf2), NULL);
1687 buf1 = gst_buffer_make_writable (buf1);
1688 buf2 = gst_buffer_make_writable (buf2);
1690 gst_buffer_resize (buf2, offset, size);
1692 len = GST_BUFFER_MEM_LEN (buf2);
1693 for (i = 0; i < len; i++) {
1696 mem = GST_BUFFER_MEM_PTR (buf2, i);
1697 GST_BUFFER_MEM_PTR (buf2, i) = NULL;
1698 _memory_add (buf1, -1, mem, FALSE);
1701 GST_BUFFER_MEM_LEN (buf2) = 0;
1702 gst_buffer_unref (buf2);
1708 * gst_buffer_get_meta:
1709 * @buffer: a #GstBuffer
1710 * @api: the #GType of an API
1712 * Get the metadata for @api on buffer. When there is no such
1713 * metadata, NULL is returned.
1715 * Returns: (transfer none): the metadata for @api on @buffer.
1718 gst_buffer_get_meta (GstBuffer * buffer, GType api)
1721 GstMeta *result = NULL;
1723 g_return_val_if_fail (buffer != NULL, NULL);
1724 g_return_val_if_fail (api != 0, NULL);
1726 /* find GstMeta of the requested API */
1727 for (item = GST_BUFFER_META (buffer); item; item = item->next) {
1728 GstMeta *meta = &item->meta;
1729 if (meta->info->api == api) {
1738 * gst_buffer_add_meta:
1739 * @buffer: a #GstBuffer
1740 * @info: a #GstMetaInfo
1741 * @params: params for @info
1743 * Add metadata for @info to @buffer using the parameters in @params.
1745 * Returns: (transfer none): the metadata for the api in @info on @buffer.
1748 gst_buffer_add_meta (GstBuffer * buffer, const GstMetaInfo * info,
1752 GstMeta *result = NULL;
1755 g_return_val_if_fail (buffer != NULL, NULL);
1756 g_return_val_if_fail (info != NULL, NULL);
1757 g_return_val_if_fail (gst_buffer_is_writable (buffer), NULL);
1759 /* create a new slice */
1760 size = ITEM_SIZE (info);
1761 item = g_slice_alloc (size);
1762 result = &item->meta;
1763 result->info = info;
1764 result->flags = GST_META_FLAG_NONE;
1766 GST_CAT_DEBUG (GST_CAT_BUFFER,
1767 "alloc metadata %p (%s) of size %" G_GSIZE_FORMAT, result,
1768 g_type_name (info->type), info->size);
1770 /* call the init_func when needed */
1771 if (info->init_func)
1772 if (!info->init_func (result, params, buffer))
1775 /* and add to the list of metadata */
1776 item->next = GST_BUFFER_META (buffer);
1777 GST_BUFFER_META (buffer) = item;
1783 g_slice_free1 (size, item);
1789 * gst_buffer_remove_meta:
1790 * @buffer: a #GstBuffer
1793 * Remove the metadata for @meta on @buffer.
1795 * Returns: %TRUE if the metadata existed and was removed, %FALSE if no such
1796 * metadata was on @buffer.
1799 gst_buffer_remove_meta (GstBuffer * buffer, GstMeta * meta)
1801 GstMetaItem *walk, *prev;
1803 g_return_val_if_fail (buffer != NULL, FALSE);
1804 g_return_val_if_fail (meta != NULL, FALSE);
1805 g_return_val_if_fail (gst_buffer_is_writable (buffer), FALSE);
1806 g_return_val_if_fail (!GST_META_FLAG_IS_SET (meta, GST_META_FLAG_LOCKED),
1809 /* find the metadata and delete */
1810 prev = GST_BUFFER_META (buffer);
1811 for (walk = prev; walk; walk = walk->next) {
1812 GstMeta *m = &walk->meta;
1814 const GstMetaInfo *info = meta->info;
1816 /* remove from list */
1817 if (GST_BUFFER_META (buffer) == walk)
1818 GST_BUFFER_META (buffer) = walk->next;
1820 prev->next = walk->next;
1821 /* call free_func if any */
1822 if (info->free_func)
1823 info->free_func (m, buffer);
1825 /* and free the slice */
1826 g_slice_free1 (ITEM_SIZE (info), walk);
1831 return walk != NULL;
1835 * gst_buffer_iterate_meta:
1836 * @buffer: a #GstBuffer
1837 * @state: an opaque state pointer
1839 * Retrieve the next #GstMeta after @current. If @state points
1840 * to %NULL, the first metadata is returned.
1842 * @state will be updated with an opage state pointer
1844 * Returns: (transfer none): The next #GstMeta or %NULL when there are
1848 gst_buffer_iterate_meta (GstBuffer * buffer, gpointer * state)
1852 g_return_val_if_fail (buffer != NULL, NULL);
1853 g_return_val_if_fail (state != NULL, NULL);
1855 meta = (GstMetaItem **) state;
1857 /* state NULL, move to first item */
1858 *meta = GST_BUFFER_META (buffer);
1860 /* state !NULL, move to next item in list */
1861 *meta = (*meta)->next;
1864 return &(*meta)->meta;
1870 * gst_buffer_foreach_meta:
1871 * @buffer: a #GstBuffer
1872 * @func: (scope call): a #GstBufferForeachMetaFunc to call
1873 * @user_data: (closure): user data passed to @func
1875 * Call @func with @user_data for each meta in @buffer.
1877 * @func can modify the passed meta pointer or its contents. The return value
1878 * of @func define if this function returns or if the remaining metadata items
1879 * in the buffer should be skipped.
1881 * Returns: %FALSE when @func returned %FALSE for one of the metadata.
1884 gst_buffer_foreach_meta (GstBuffer * buffer, GstBufferForeachMetaFunc func,
1887 GstMetaItem *walk, *prev, *next;
1888 gboolean res = TRUE;
1890 g_return_val_if_fail (buffer != NULL, FALSE);
1891 g_return_val_if_fail (func != NULL, FALSE);
1893 /* find the metadata and delete */
1894 prev = GST_BUFFER_META (buffer);
1895 for (walk = prev; walk; walk = next) {
1898 m = new = &walk->meta;
1901 res = func (buffer, &new, user_data);
1904 const GstMetaInfo *info = m->info;
1906 GST_CAT_DEBUG (GST_CAT_BUFFER, "remove metadata %p (%s)", m,
1907 g_type_name (info->type));
1909 g_return_val_if_fail (gst_buffer_is_writable (buffer), FALSE);
1910 g_return_val_if_fail (!GST_META_FLAG_IS_SET (m, GST_META_FLAG_LOCKED),
1913 /* remove from list */
1914 if (GST_BUFFER_META (buffer) == walk)
1915 GST_BUFFER_META (buffer) = next;
1919 /* call free_func if any */
1920 if (info->free_func)
1921 info->free_func (m, buffer);
1923 /* and free the slice */
1924 g_slice_free1 (ITEM_SIZE (info), walk);