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 #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 = 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_size (buffer);
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 < 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_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)
766 newbuf = gst_buffer_new ();
767 gst_buffer_append_memory (newbuf,
768 gst_memory_new_wrapped (flags, data, maxsize, offset, size,
775 * gst_buffer_new_wrapped:
776 * @data: (array length=size) (element-type guint8) (transfer full): data to wrap
777 * @size: allocated size of @data
779 * Creates a new buffer that wraps the given @data. The memory will be freed
780 * with g_free and will be marked writable.
784 * Returns: (transfer full): a new #GstBuffer
787 gst_buffer_new_wrapped (gpointer data, gsize size)
789 return gst_buffer_new_wrapped_full (0, data, size, 0, size, data, g_free);
793 * gst_buffer_n_memory:
794 * @buffer: a #GstBuffer.
796 * Get the amount of memory blocks that this buffer has. This amount is never
797 * larger than what gst_buffer_get_max_memory() returns.
799 * Returns: (transfer full): the amount of memory block in this buffer.
802 gst_buffer_n_memory (GstBuffer * buffer)
804 g_return_val_if_fail (GST_IS_BUFFER (buffer), 0);
806 return GST_BUFFER_MEM_LEN (buffer);
810 * gst_buffer_prepend_memory:
811 * @buffer: a #GstBuffer.
812 * @mem: (transfer full): a #GstMemory.
814 * Prepend the memory block @mem to @buffer. This function takes
815 * ownership of @mem and thus doesn't increase its refcount.
817 * This function is identical to gst_buffer_insert_memory() with an index of 0.
818 * See gst_buffer_insert_memory() for more details.
821 gst_buffer_prepend_memory (GstBuffer * buffer, GstMemory * mem)
823 gst_buffer_insert_memory (buffer, 0, mem);
827 * gst_buffer_append_memory:
828 * @buffer: a #GstBuffer.
829 * @mem: (transfer full): a #GstMemory.
831 * Append the memory block @mem to @buffer. This function takes
832 * ownership of @mem and thus doesn't increase its refcount.
834 * This function is identical to gst_buffer_insert_memory() with an index of -1.
835 * See gst_buffer_insert_memory() for more details.
838 gst_buffer_append_memory (GstBuffer * buffer, GstMemory * mem)
840 gst_buffer_insert_memory (buffer, -1, mem);
844 * gst_buffer_insert_memory:
845 * @buffer: a #GstBuffer.
846 * @idx: the index to add the memory at, or -1 to append it to the end
847 * @mem: (transfer full): a #GstMemory.
849 * Insert the memory block @mem to @buffer at @idx. This function takes ownership
850 * of @mem and thus doesn't increase its refcount.
852 * Only gst_buffer_get_max_memory() can be added to a buffer. If more memory is
853 * added, existing memory blocks will automatically be merged to make room for
857 gst_buffer_insert_memory (GstBuffer * buffer, gint idx, GstMemory * mem)
859 g_return_if_fail (GST_IS_BUFFER (buffer));
860 g_return_if_fail (gst_buffer_is_writable (buffer));
861 g_return_if_fail (mem != NULL);
862 g_return_if_fail (idx == -1 ||
863 (idx >= 0 && idx <= GST_BUFFER_MEM_LEN (buffer)));
865 _memory_add (buffer, idx, mem, TRUE);
869 _get_mapped (GstBuffer * buffer, guint idx, GstMapInfo * info,
872 GstMemory *mem, *mapped;
874 mem = gst_memory_ref (GST_BUFFER_MEM_PTR (buffer, idx));
876 mapped = gst_memory_make_mapped (mem, info, flags);
879 /* memory changed, lock new memory */
880 gst_memory_lock (mapped, GST_LOCK_FLAG_EXCLUSIVE);
881 GST_BUFFER_MEM_PTR (buffer, idx) = mapped;
882 /* unlock old memory */
883 gst_memory_unlock (mem, GST_LOCK_FLAG_EXCLUSIVE);
885 gst_memory_unref (mem);
891 * gst_buffer_peek_memory:
892 * @buffer: a #GstBuffer.
895 * Get the memory block at @idx in @buffer. The memory block stays valid until
896 * the memory block in @buffer is removed, replaced or merged, typically with
897 * any call that modifies the memory in @buffer.
899 * Since this call does not influence the refcount of the memory,
900 * gst_memory_is_writable() can be used to check if @buffer is the sole owner
901 * of the returned memory.
903 * Returns: (transfer none): the #GstMemory at @idx.
906 gst_buffer_peek_memory (GstBuffer * buffer, guint idx)
910 g_return_val_if_fail (GST_IS_BUFFER (buffer), NULL);
911 len = GST_BUFFER_MEM_LEN (buffer);
912 g_return_val_if_fail (idx < len, NULL);
914 return GST_BUFFER_MEM_PTR (buffer, idx);
918 * gst_buffer_get_memory:
919 * @buffer: a #GstBuffer.
922 * Get the memory block at index @idx in @buffer.
924 * Returns: (transfer full): a #GstMemory that contains the data of the
925 * memory block at @idx. Use gst_memory_unref () after usage.
928 gst_buffer_get_memory (GstBuffer * buffer, guint idx)
930 return gst_buffer_get_memory_range (buffer, idx, 1);
934 * gst_buffer_get_all_memory:
935 * @buffer: a #GstBuffer.
937 * Get all the memory block in @buffer. The memory blocks will be merged
938 * into one large #GstMemory.
940 * Returns: (transfer full): a #GstMemory that contains the merged memory.
941 * Use gst_memory_unref () after usage.
944 gst_buffer_get_all_memory (GstBuffer * buffer)
946 return gst_buffer_get_memory_range (buffer, 0, -1);
950 * gst_buffer_get_memory_range:
951 * @buffer: a #GstBuffer.
955 * Get @length memory blocks in @buffer starting at @idx. The memory blocks will
956 * be merged into one large #GstMemory.
958 * If @length is -1, all memory starting from @idx is merged.
960 * Returns: (transfer full): a #GstMemory that contains the merged data of @length
961 * blocks starting at @idx. Use gst_memory_unref () after usage.
964 gst_buffer_get_memory_range (GstBuffer * buffer, guint idx, gint length)
968 GST_CAT_DEBUG (GST_CAT_BUFFER, "idx %u, length %d", idx, length);
970 g_return_val_if_fail (GST_IS_BUFFER (buffer), NULL);
971 len = GST_BUFFER_MEM_LEN (buffer);
972 g_return_val_if_fail ((len == 0 && idx == 0 && length == -1) ||
973 (length == -1 && idx < len) || (length > 0 && length + idx <= len), NULL);
978 return _get_merged_memory (buffer, idx, length);
982 * gst_buffer_replace_memory:
983 * @buffer: a #GstBuffer.
985 * @mem: (transfer full): a #GstMemory
987 * Replaces the memory block at index @idx in @buffer with @mem.
990 gst_buffer_replace_memory (GstBuffer * buffer, guint idx, GstMemory * mem)
992 gst_buffer_replace_memory_range (buffer, idx, 1, mem);
996 * gst_buffer_replace_all_memory:
997 * @buffer: a #GstBuffer.
998 * @mem: (transfer full): a #GstMemory
1000 * Replaces all memory in @buffer with @mem.
1003 gst_buffer_replace_all_memory (GstBuffer * buffer, GstMemory * mem)
1005 gst_buffer_replace_memory_range (buffer, 0, -1, mem);
1009 * gst_buffer_replace_memory_range:
1010 * @buffer: a #GstBuffer.
1012 * @length: a length should not be 0
1013 * @mem: (transfer full): a #GstMemory
1015 * Replaces @length memory blocks in @buffer starting at @idx with @mem.
1017 * If @length is -1, all memory starting from @idx will be removed and
1018 * replaced with @mem.
1020 * @buffer should be writable.
1023 gst_buffer_replace_memory_range (GstBuffer * buffer, guint idx, gint length,
1028 g_return_if_fail (GST_IS_BUFFER (buffer));
1029 g_return_if_fail (gst_buffer_is_writable (buffer));
1031 GST_CAT_DEBUG (GST_CAT_BUFFER, "idx %u, length %d, %p", idx, length, mem);
1033 len = GST_BUFFER_MEM_LEN (buffer);
1034 g_return_if_fail ((len == 0 && idx == 0 && length == -1) ||
1035 (length == -1 && idx < len) || (length > 0 && length + idx <= len));
1040 _replace_memory (buffer, len, idx, length, mem);
1044 * gst_buffer_remove_memory:
1045 * @buffer: a #GstBuffer.
1048 * Remove the memory block in @b at index @i.
1051 gst_buffer_remove_memory (GstBuffer * buffer, guint idx)
1053 gst_buffer_remove_memory_range (buffer, idx, 1);
1057 * gst_buffer_remove_all_memory:
1058 * @buffer: a #GstBuffer.
1060 * Remove all the memory blocks in @buffer.
1063 gst_buffer_remove_all_memory (GstBuffer * buffer)
1065 gst_buffer_remove_memory_range (buffer, 0, -1);
1069 * gst_buffer_remove_memory_range:
1070 * @buffer: a #GstBuffer.
1074 * Remove @length memory blocks in @buffer starting from @idx.
1076 * @length can be -1, in which case all memory starting from @idx is removed.
1079 gst_buffer_remove_memory_range (GstBuffer * buffer, guint idx, gint length)
1083 g_return_if_fail (GST_IS_BUFFER (buffer));
1084 g_return_if_fail (gst_buffer_is_writable (buffer));
1086 GST_CAT_DEBUG (GST_CAT_BUFFER, "idx %u, length %d", idx, length);
1088 len = GST_BUFFER_MEM_LEN (buffer);
1089 g_return_if_fail ((len == 0 && idx == 0 && length == -1) ||
1090 (length == -1 && idx < len) || length + idx <= len);
1095 _replace_memory (buffer, len, idx, length, NULL);
1099 * gst_buffer_find_memory:
1100 * @buffer: a #GstBuffer.
1101 * @offset: an offset
1103 * @idx: (out): pointer to index
1104 * @length: (out): pointer to length
1105 * @skip: (out): pointer to skip
1107 * Find the memory blocks that span @size bytes starting from @offset
1110 * When this function returns %TRUE, @idx will contain the index of the first
1111 * memory bock where the byte for @offset can be found and @length contains the
1112 * number of memory blocks containing the @size remaining bytes. @skip contains
1113 * the number of bytes to skip in the memory bock at @idx to get to the byte
1116 * @size can be -1 to get all the memory blocks after @idx.
1118 * Returns: %TRUE when @size bytes starting from @offset could be found in
1119 * @buffer and @idx, @length and @skip will be filled.
1122 gst_buffer_find_memory (GstBuffer * buffer, gsize offset, gsize size,
1123 guint * idx, guint * length, gsize * skip)
1125 guint i, len, found;
1127 g_return_val_if_fail (GST_IS_BUFFER (buffer), FALSE);
1128 g_return_val_if_fail (idx != NULL, FALSE);
1129 g_return_val_if_fail (length != NULL, FALSE);
1130 g_return_val_if_fail (skip != NULL, FALSE);
1132 len = GST_BUFFER_MEM_LEN (buffer);
1135 for (i = 0; i < len; i++) {
1139 mem = GST_BUFFER_MEM_PTR (buffer, i);
1140 s = gst_memory_get_sizes (mem, NULL, NULL);
1143 /* block before offset, or empty block, skip */
1146 /* block after offset */
1148 /* first block, remember index and offset */
1152 /* return remaining blocks */
1159 /* count the amount of found bytes */
1161 if (found >= size) {
1162 /* we have enough bytes */
1163 *length = i - *idx + 1;
1172 * gst_buffer_get_sizes:
1173 * @buffer: a #GstBuffer.
1174 * @offset: (out): a pointer to the offset
1175 * @maxsize: (out): a pointer to the maxsize
1177 * Get the total size of the memory blocks in @b.
1179 * When not %NULL, @offset will contain the offset of the data in the
1180 * first memory block in @buffer and @maxsize will contain the sum of
1181 * the size and @offset and the amount of extra padding on the last
1182 * memory block. @offset and @maxsize can be used to resize the
1183 * buffer memory blocks with gst_buffer_resize().
1185 * Returns: total size of the memory blocks in @buffer.
1188 gst_buffer_get_sizes (GstBuffer * buffer, gsize * offset, gsize * maxsize)
1190 return gst_buffer_get_sizes_range (buffer, 0, -1, offset, maxsize);
1194 * gst_buffer_get_size:
1195 * @buffer: a #GstBuffer.
1197 * Get the total size of the memory blocks in @buffer.
1199 * Returns: total size of the memory blocks in @buffer.
1202 gst_buffer_get_size (GstBuffer * buffer)
1204 return gst_buffer_get_sizes_range (buffer, 0, -1, NULL, NULL);
1208 * gst_buffer_get_sizes_range:
1209 * @buffer: a #GstBuffer.
1212 * @offset: (out): a pointer to the offset
1213 * @maxsize: (out): a pointer to the maxsize
1215 * Get the total size of @length memory blocks stating from @idx in @buffer.
1217 * When not %NULL, @offset will contain the offset of the data in the
1218 * memory block in @buffer at @idx and @maxsize will contain the sum of the size
1219 * and @offset and the amount of extra padding on the memory block at @idx +
1221 * @offset and @maxsize can be used to resize the buffer memory blocks with
1222 * gst_buffer_resize_range().
1224 * Returns: total size of @length memory blocks starting at @idx in @buffer.
1227 gst_buffer_get_sizes_range (GstBuffer * buffer, guint idx, gint length,
1228 gsize * offset, gsize * maxsize)
1234 g_return_val_if_fail (GST_IS_BUFFER (buffer), 0);
1235 len = GST_BUFFER_MEM_LEN (buffer);
1236 g_return_val_if_fail ((len == 0 && idx == 0 && length == -1) ||
1237 (length == -1 && idx < len) || (length + idx <= len), 0);
1242 if (G_LIKELY (length == 1)) {
1244 mem = GST_BUFFER_MEM_PTR (buffer, idx);
1245 size = gst_memory_get_sizes (mem, offset, maxsize);
1251 size = offs = extra = 0;
1252 for (i = idx; i < end; i++) {
1255 mem = GST_BUFFER_MEM_PTR (buffer, i);
1256 s = gst_memory_get_sizes (mem, &o, &ms);
1260 /* first size, take accumulated data before as the offset */
1264 /* save the amount of data after this block */
1265 extra = ms - (o + s);
1267 /* empty block, add as extra */
1274 *maxsize = offs + size + extra;
1280 * gst_buffer_resize:
1281 * @buffer: a #GstBuffer.
1282 * @offset: the offset adjustement
1283 * @size: the new size or -1 to just adjust the offset
1285 * Set the offset and total size of the memory blocks in @buffer.
1288 gst_buffer_resize (GstBuffer * buffer, gssize offset, gssize size)
1290 gst_buffer_resize_range (buffer, 0, -1, offset, size);
1294 * gst_buffer_set_size:
1295 * @buffer: a #GstBuffer.
1296 * @size: the new size
1298 * Set the total size of the memory blocks in @buffer.
1301 gst_buffer_set_size (GstBuffer * buffer, gssize size)
1303 gst_buffer_resize_range (buffer, 0, -1, 0, size);
1307 * gst_buffer_resize_range:
1308 * @buffer: a #GstBuffer.
1311 * @offset: the offset adjustement
1312 * @size: the new size or -1 to just adjust the offset
1314 * Set the total size of the @length memory blocks starting at @idx in
1317 * Returns: %TRUE if resizing succeeded, %FALSE otherwise.
1320 gst_buffer_resize_range (GstBuffer * buffer, guint idx, gint length,
1321 gssize offset, gssize size)
1324 gsize bsize, bufsize, bufoffs, bufmax;
1326 g_return_val_if_fail (gst_buffer_is_writable (buffer), FALSE);
1327 g_return_val_if_fail (size >= -1, FALSE);
1329 len = GST_BUFFER_MEM_LEN (buffer);
1330 g_return_val_if_fail ((len == 0 && idx == 0 && length == -1) ||
1331 (length == -1 && idx < len) || (length + idx <= len), FALSE);
1336 bufsize = gst_buffer_get_sizes_range (buffer, idx, length, &bufoffs, &bufmax);
1338 GST_CAT_LOG (GST_CAT_BUFFER, "trim %p %" G_GSSIZE_FORMAT "-%" G_GSSIZE_FORMAT
1339 " size:%" G_GSIZE_FORMAT " offs:%" G_GSIZE_FORMAT " max:%"
1340 G_GSIZE_FORMAT, buffer, offset, size, bufsize, bufoffs, bufmax);
1342 /* we can't go back further than the current offset or past the end of the
1344 g_return_val_if_fail ((offset < 0 && bufoffs >= -offset) || (offset >= 0
1345 && bufoffs + offset <= bufmax), FALSE);
1347 g_return_val_if_fail (bufsize >= offset, FALSE);
1348 size = bufsize - offset;
1350 g_return_val_if_fail (bufmax >= bufoffs + offset + size, FALSE);
1353 if (offset == 0 && size == bufsize)
1358 for (i = idx; i < end; i++) {
1362 mem = GST_BUFFER_MEM_PTR (buffer, i);
1363 bsize = gst_memory_get_sizes (mem, NULL, NULL);
1366 /* last buffer always gets resized to the remaining size */
1369 /* shrink buffers before the offset */
1370 else if ((gssize) bsize <= offset) {
1372 noffs = offset - bsize;
1375 /* clip other buffers */
1377 left = MIN (bsize - offset, size);
1379 if (offset != 0 || left != bsize) {
1380 if (gst_memory_is_writable (mem)) {
1381 gst_memory_resize (mem, offset, left);
1383 GstMemory *newmem = NULL;
1385 if (!GST_MEMORY_IS_NO_SHARE (mem))
1386 newmem = gst_memory_share (mem, offset, left);
1389 newmem = gst_memory_copy (mem, offset, left);
1394 gst_memory_lock (newmem, GST_LOCK_FLAG_EXCLUSIVE);
1395 GST_BUFFER_MEM_PTR (buffer, i) = newmem;
1396 gst_memory_unlock (mem, GST_LOCK_FLAG_EXCLUSIVE);
1397 gst_memory_unref (mem);
1410 * @buffer: a #GstBuffer.
1411 * @info: (out): info about the mapping
1412 * @flags: flags for the mapping
1414 * This function fills @info with the #GstMapInfo of all merged memory
1415 * blocks in @buffer.
1417 * @flags describe the desired access of the memory. When @flags is
1418 * #GST_MAP_WRITE, @buffer should be writable (as returned from
1419 * gst_buffer_is_writable()).
1421 * When @buffer is writable but the memory isn't, a writable copy will
1422 * automatically be created and returned. The readonly copy of the
1423 * buffer memory will then also be replaced with this writable copy.
1425 * The memory in @info should be unmapped with gst_buffer_unmap() after
1428 * Returns: %TRUE if the map succeeded and @info contains valid data.
1431 gst_buffer_map (GstBuffer * buffer, GstMapInfo * info, GstMapFlags flags)
1433 return gst_buffer_map_range (buffer, 0, -1, info, flags);
1437 * gst_buffer_map_range:
1438 * @buffer: a #GstBuffer.
1441 * @info: (out): info about the mapping
1442 * @flags: flags for the mapping
1444 * This function fills @info with the #GstMapInfo of @length merged memory blocks
1445 * starting at @idx in @buffer. When @length is -1, all memory blocks starting
1446 * from @idx are merged and mapped.
1448 * @flags describe the desired access of the memory. When @flags is
1449 * #GST_MAP_WRITE, @buffer should be writable (as returned from
1450 * gst_buffer_is_writable()).
1452 * When @buffer is writable but the memory isn't, a writable copy will
1453 * automatically be created and returned. The readonly copy of the buffer memory
1454 * will then also be replaced with this writable copy.
1456 * The memory in @info should be unmapped with gst_buffer_unmap() after usage.
1458 * Returns: %TRUE if the map succeeded and @info contains valid
1462 gst_buffer_map_range (GstBuffer * buffer, guint idx, gint length,
1463 GstMapInfo * info, GstMapFlags flags)
1465 GstMemory *mem, *nmem;
1466 gboolean write, writable;
1469 g_return_val_if_fail (GST_IS_BUFFER (buffer), FALSE);
1470 g_return_val_if_fail (info != NULL, FALSE);
1471 len = GST_BUFFER_MEM_LEN (buffer);
1472 g_return_val_if_fail ((len == 0 && idx == 0 && length == -1) ||
1473 (length == -1 && idx < len) || (length > 0
1474 && length + idx <= len), FALSE);
1476 GST_CAT_LOG (GST_CAT_BUFFER, "buffer %p, idx %u, length %d, flags %04x",
1477 buffer, idx, length, flags);
1479 write = (flags & GST_MAP_WRITE) != 0;
1480 writable = gst_buffer_is_writable (buffer);
1482 /* check if we can write when asked for write access */
1483 if (G_UNLIKELY (write && !writable))
1489 mem = _get_merged_memory (buffer, idx, length);
1490 if (G_UNLIKELY (mem == NULL))
1493 /* now try to map */
1494 nmem = gst_memory_make_mapped (mem, info, flags);
1495 if (G_UNLIKELY (nmem == NULL))
1498 /* if we merged or when the map returned a different memory, we try to replace
1499 * the memory in the buffer */
1500 if (G_UNLIKELY (length > 1 || nmem != mem)) {
1501 /* if the buffer is writable, replace the memory */
1503 _replace_memory (buffer, len, idx, length, gst_memory_ref (nmem));
1506 GST_CAT_DEBUG (GST_CAT_PERFORMANCE,
1507 "temporary mapping for memory %p in buffer %p", nmem, buffer);
1516 GST_WARNING_OBJECT (buffer, "write map requested on non-writable buffer");
1517 g_critical ("write map requested on non-writable buffer");
1522 /* empty buffer, we need to return NULL */
1523 GST_DEBUG_OBJECT (buffer, "can't get buffer memory");
1524 info->memory = NULL;
1532 GST_DEBUG_OBJECT (buffer, "cannot map memory");
1539 * @buffer: a #GstBuffer.
1540 * @info: a #GstMapInfo
1542 * Release the memory previously mapped with gst_buffer_map().
1545 gst_buffer_unmap (GstBuffer * buffer, GstMapInfo * info)
1547 g_return_if_fail (GST_IS_BUFFER (buffer));
1548 g_return_if_fail (info != NULL);
1550 /* we need to check for NULL, it is possible that we tried to map a buffer
1551 * without memory and we should be able to unmap that fine */
1552 if (G_LIKELY (info->memory)) {
1553 gst_memory_unmap (info->memory, info);
1554 gst_memory_unref (info->memory);
1560 * @buffer: a #GstBuffer.
1561 * @offset: the offset to fill
1562 * @src: (array length=size) (element-type guint8): the source address
1563 * @size: the size to fill
1565 * Copy @size bytes from @src to @buffer at @offset.
1567 * Returns: The amount of bytes copied. This value can be lower than @size
1568 * when @buffer did not contain enough data.
1571 gst_buffer_fill (GstBuffer * buffer, gsize offset, gconstpointer src,
1575 const guint8 *ptr = src;
1577 g_return_val_if_fail (GST_IS_BUFFER (buffer), 0);
1578 g_return_val_if_fail (gst_buffer_is_writable (buffer), 0);
1579 g_return_val_if_fail (src != NULL || size == 0, 0);
1581 GST_CAT_LOG (GST_CAT_BUFFER,
1582 "buffer %p, offset %" G_GSIZE_FORMAT ", size %" G_GSIZE_FORMAT, buffer,
1585 len = GST_BUFFER_MEM_LEN (buffer);
1588 for (i = 0; i < len && left > 0; i++) {
1593 mem = _get_mapped (buffer, i, &info, GST_MAP_WRITE);
1594 if (info.size > offset) {
1595 /* we have enough */
1596 tocopy = MIN (info.size - offset, left);
1597 memcpy ((guint8 *) info.data + offset, ptr, tocopy);
1602 /* offset past buffer, skip */
1603 offset -= info.size;
1605 gst_memory_unmap (mem, &info);
1611 * gst_buffer_extract:
1612 * @buffer: a #GstBuffer.
1613 * @offset: the offset to extract
1614 * @dest: the destination address
1615 * @size: the size to extract
1617 * Copy @size bytes starting from @offset in @buffer to @dest.
1619 * Returns: The amount of bytes extracted. This value can be lower than @size
1620 * when @buffer did not contain enough data.
1623 gst_buffer_extract (GstBuffer * buffer, gsize offset, gpointer dest, gsize size)
1628 g_return_val_if_fail (GST_IS_BUFFER (buffer), 0);
1629 g_return_val_if_fail (dest != NULL, 0);
1631 GST_CAT_LOG (GST_CAT_BUFFER,
1632 "buffer %p, offset %" G_GSIZE_FORMAT ", size %" G_GSIZE_FORMAT, buffer,
1635 len = GST_BUFFER_MEM_LEN (buffer);
1638 for (i = 0; i < len && left > 0; i++) {
1643 mem = _get_mapped (buffer, i, &info, GST_MAP_READ);
1644 if (info.size > offset) {
1645 /* we have enough */
1646 tocopy = MIN (info.size - offset, left);
1647 memcpy (ptr, (guint8 *) info.data + offset, tocopy);
1652 /* offset past buffer, skip */
1653 offset -= info.size;
1655 gst_memory_unmap (mem, &info);
1661 * gst_buffer_memcmp:
1662 * @buffer: a #GstBuffer.
1663 * @offset: the offset in @buffer
1664 * @mem: (array length=size) (element-type guint8): the memory to compare
1665 * @size: the size to compare
1667 * Compare @size bytes starting from @offset in @buffer with the memory in @mem.
1669 * Returns: 0 if the memory is equal.
1672 gst_buffer_memcmp (GstBuffer * buffer, gsize offset, gconstpointer mem,
1676 const guint8 *ptr = mem;
1679 g_return_val_if_fail (GST_IS_BUFFER (buffer), 0);
1680 g_return_val_if_fail (mem != NULL, 0);
1682 GST_CAT_LOG (GST_CAT_BUFFER,
1683 "buffer %p, offset %" G_GSIZE_FORMAT ", size %" G_GSIZE_FORMAT, buffer,
1686 len = GST_BUFFER_MEM_LEN (buffer);
1688 for (i = 0; i < len && size > 0 && res == 0; i++) {
1693 mem = _get_mapped (buffer, i, &info, GST_MAP_READ);
1694 if (info.size > offset) {
1695 /* we have enough */
1696 tocmp = MIN (info.size - offset, size);
1697 res = memcmp (ptr, (guint8 *) info.data + offset, tocmp);
1702 /* offset past buffer, skip */
1703 offset -= info.size;
1705 gst_memory_unmap (mem, &info);
1711 * gst_buffer_memset:
1712 * @buffer: a #GstBuffer.
1713 * @offset: the offset in @buffer
1714 * @val: the value to set
1715 * @size: the size to set
1717 * Fill @buf with @size bytes with @val starting from @offset.
1719 * Returns: The amount of bytes filled. This value can be lower than @size
1720 * when @buffer did not contain enough data.
1723 gst_buffer_memset (GstBuffer * buffer, gsize offset, guint8 val, gsize size)
1727 g_return_val_if_fail (GST_IS_BUFFER (buffer), 0);
1728 g_return_val_if_fail (gst_buffer_is_writable (buffer), 0);
1730 GST_CAT_LOG (GST_CAT_BUFFER,
1731 "buffer %p, offset %" G_GSIZE_FORMAT ", val %02x, size %" G_GSIZE_FORMAT,
1732 buffer, offset, val, size);
1734 len = GST_BUFFER_MEM_LEN (buffer);
1737 for (i = 0; i < len && left > 0; i++) {
1742 mem = _get_mapped (buffer, i, &info, GST_MAP_WRITE);
1743 if (info.size > offset) {
1744 /* we have enough */
1745 toset = MIN (info.size - offset, left);
1746 memset ((guint8 *) info.data + offset, val, toset);
1750 /* offset past buffer, skip */
1751 offset -= info.size;
1753 gst_memory_unmap (mem, &info);
1759 * gst_buffer_copy_region:
1760 * @parent: a #GstBuffer.
1761 * @flags: the #GstBufferCopyFlags
1762 * @offset: the offset into parent #GstBuffer at which the new sub-buffer
1764 * @size: the size of the new #GstBuffer sub-buffer, in bytes.
1766 * Creates a sub-buffer from @parent at @offset and @size.
1767 * This sub-buffer uses the actual memory space of the parent buffer.
1768 * This function will copy the offset and timestamp fields when the
1769 * offset is 0. If not, they will be set to #GST_CLOCK_TIME_NONE and
1770 * #GST_BUFFER_OFFSET_NONE.
1771 * If @offset equals 0 and @size equals the total size of @buffer, the
1772 * duration and offset end fields are also copied. If not they will be set
1773 * to #GST_CLOCK_TIME_NONE and #GST_BUFFER_OFFSET_NONE.
1777 * Returns: (transfer full): the new #GstBuffer or NULL if the arguments were
1781 gst_buffer_copy_region (GstBuffer * buffer, GstBufferCopyFlags flags,
1782 gsize offset, gsize size)
1786 g_return_val_if_fail (buffer != NULL, NULL);
1788 /* create the new buffer */
1789 copy = gst_buffer_new ();
1791 GST_CAT_LOG (GST_CAT_BUFFER, "new region copy %p of %p %" G_GSIZE_FORMAT
1792 "-%" G_GSIZE_FORMAT, copy, buffer, offset, size);
1794 if (!gst_buffer_copy_into (copy, buffer, flags, offset, size))
1795 gst_buffer_replace (©, NULL);
1801 * gst_buffer_append:
1802 * @buf1: (transfer full): the first source #GstBuffer to append.
1803 * @buf2: (transfer full): the second source #GstBuffer to append.
1805 * Append all the memory from @buf2 to @buf1. The result buffer will contain a
1806 * concatenation of the memory of @buf1 and @buf2.
1808 * Returns: (transfer full): the new #GstBuffer that contains the memory
1809 * of the two source buffers.
1812 gst_buffer_append (GstBuffer * buf1, GstBuffer * buf2)
1814 return gst_buffer_append_region (buf1, buf2, 0, -1);
1818 * gst_buffer_append_region:
1819 * @buf1: (transfer full): the first source #GstBuffer to append.
1820 * @buf2: (transfer full): the second source #GstBuffer to append.
1821 * @offset: the offset in @buf2
1822 * @size: the size or -1 of @buf2
1824 * Append @size bytes at @offset from @buf2 to @buf1. The result buffer will
1825 * contain a concatenation of the memory of @buf1 and the requested region of
1828 * Returns: (transfer full): the new #GstBuffer that contains the memory
1829 * of the two source buffers.
1832 gst_buffer_append_region (GstBuffer * buf1, GstBuffer * buf2, gssize offset,
1837 g_return_val_if_fail (GST_IS_BUFFER (buf1), NULL);
1838 g_return_val_if_fail (GST_IS_BUFFER (buf2), NULL);
1840 buf1 = gst_buffer_make_writable (buf1);
1841 buf2 = gst_buffer_make_writable (buf2);
1843 gst_buffer_resize (buf2, offset, size);
1845 len = GST_BUFFER_MEM_LEN (buf2);
1846 for (i = 0; i < len; i++) {
1849 mem = GST_BUFFER_MEM_PTR (buf2, i);
1850 GST_BUFFER_MEM_PTR (buf2, i) = NULL;
1851 _memory_add (buf1, -1, mem, FALSE);
1854 GST_BUFFER_MEM_LEN (buf2) = 0;
1855 gst_buffer_unref (buf2);
1861 * gst_buffer_get_meta:
1862 * @buffer: a #GstBuffer
1863 * @api: the #GType of an API
1865 * Get the metadata for @api on buffer. When there is no such
1866 * metadata, NULL is returned.
1868 * Returns: (transfer none): the metadata for @api on @buffer.
1871 gst_buffer_get_meta (GstBuffer * buffer, GType api)
1874 GstMeta *result = NULL;
1876 g_return_val_if_fail (buffer != NULL, NULL);
1877 g_return_val_if_fail (api != 0, NULL);
1879 /* find GstMeta of the requested API */
1880 for (item = GST_BUFFER_META (buffer); item; item = item->next) {
1881 GstMeta *meta = &item->meta;
1882 if (meta->info->api == api) {
1891 * gst_buffer_add_meta:
1892 * @buffer: a #GstBuffer
1893 * @info: a #GstMetaInfo
1894 * @params: params for @info
1896 * Add metadata for @info to @buffer using the parameters in @params.
1898 * Returns: (transfer none): the metadata for the api in @info on @buffer.
1901 gst_buffer_add_meta (GstBuffer * buffer, const GstMetaInfo * info,
1905 GstMeta *result = NULL;
1908 g_return_val_if_fail (buffer != NULL, NULL);
1909 g_return_val_if_fail (info != NULL, NULL);
1910 g_return_val_if_fail (gst_buffer_is_writable (buffer), NULL);
1912 /* create a new slice */
1913 size = ITEM_SIZE (info);
1914 item = g_slice_alloc (size);
1915 result = &item->meta;
1916 result->info = info;
1917 result->flags = GST_META_FLAG_NONE;
1919 GST_CAT_DEBUG (GST_CAT_BUFFER,
1920 "alloc metadata %p (%s) of size %" G_GSIZE_FORMAT, result,
1921 g_type_name (info->type), info->size);
1923 /* call the init_func when needed */
1924 if (info->init_func)
1925 if (!info->init_func (result, params, buffer))
1928 /* and add to the list of metadata */
1929 item->next = GST_BUFFER_META (buffer);
1930 GST_BUFFER_META (buffer) = item;
1936 g_slice_free1 (size, item);
1942 * gst_buffer_remove_meta:
1943 * @buffer: a #GstBuffer
1946 * Remove the metadata for @meta on @buffer.
1948 * Returns: %TRUE if the metadata existed and was removed, %FALSE if no such
1949 * metadata was on @buffer.
1952 gst_buffer_remove_meta (GstBuffer * buffer, GstMeta * meta)
1954 GstMetaItem *walk, *prev;
1956 g_return_val_if_fail (buffer != NULL, FALSE);
1957 g_return_val_if_fail (meta != NULL, FALSE);
1958 g_return_val_if_fail (gst_buffer_is_writable (buffer), FALSE);
1959 g_return_val_if_fail (!GST_META_FLAG_IS_SET (meta, GST_META_FLAG_LOCKED),
1962 /* find the metadata and delete */
1963 prev = GST_BUFFER_META (buffer);
1964 for (walk = prev; walk; walk = walk->next) {
1965 GstMeta *m = &walk->meta;
1967 const GstMetaInfo *info = meta->info;
1969 /* remove from list */
1970 if (GST_BUFFER_META (buffer) == walk)
1971 GST_BUFFER_META (buffer) = walk->next;
1973 prev->next = walk->next;
1974 /* call free_func if any */
1975 if (info->free_func)
1976 info->free_func (m, buffer);
1978 /* and free the slice */
1979 g_slice_free1 (ITEM_SIZE (info), walk);
1984 return walk != NULL;
1988 * gst_buffer_iterate_meta:
1989 * @buffer: a #GstBuffer
1990 * @state: an opaque state pointer
1992 * Retrieve the next #GstMeta after @current. If @state points
1993 * to %NULL, the first metadata is returned.
1995 * @state will be updated with an opage state pointer
1997 * Returns: (transfer none): The next #GstMeta or %NULL when there are
2001 gst_buffer_iterate_meta (GstBuffer * buffer, gpointer * state)
2005 g_return_val_if_fail (buffer != NULL, NULL);
2006 g_return_val_if_fail (state != NULL, NULL);
2008 meta = (GstMetaItem **) state;
2010 /* state NULL, move to first item */
2011 *meta = GST_BUFFER_META (buffer);
2013 /* state !NULL, move to next item in list */
2014 *meta = (*meta)->next;
2017 return &(*meta)->meta;
2023 * gst_buffer_foreach_meta:
2024 * @buffer: a #GstBuffer
2025 * @func: (scope call): a #GstBufferForeachMetaFunc to call
2026 * @user_data: (closure): user data passed to @func
2028 * Call @func with @user_data for each meta in @buffer.
2030 * @func can modify the passed meta pointer or its contents. The return value
2031 * of @func define if this function returns or if the remaining metadata items
2032 * in the buffer should be skipped.
2034 * Returns: %FALSE when @func returned %FALSE for one of the metadata.
2037 gst_buffer_foreach_meta (GstBuffer * buffer, GstBufferForeachMetaFunc func,
2040 GstMetaItem *walk, *prev, *next;
2041 gboolean res = TRUE;
2043 g_return_val_if_fail (buffer != NULL, FALSE);
2044 g_return_val_if_fail (func != NULL, FALSE);
2046 /* find the metadata and delete */
2047 prev = GST_BUFFER_META (buffer);
2048 for (walk = prev; walk; walk = next) {
2051 m = new = &walk->meta;
2054 res = func (buffer, &new, user_data);
2057 const GstMetaInfo *info = m->info;
2059 GST_CAT_DEBUG (GST_CAT_BUFFER, "remove metadata %p (%s)", m,
2060 g_type_name (info->type));
2062 g_return_val_if_fail (gst_buffer_is_writable (buffer), FALSE);
2063 g_return_val_if_fail (!GST_META_FLAG_IS_SET (m, GST_META_FLAG_LOCKED),
2066 /* remove from list */
2067 if (GST_BUFFER_META (buffer) == walk)
2068 GST_BUFFER_META (buffer) = next;
2072 /* call free_func if any */
2073 if (info->free_func)
2074 info->free_func (m, buffer);
2076 /* and free the slice */
2077 g_slice_free1 (ITEM_SIZE (info), walk);
2086 * gst_buffer_extract_dup:
2087 * @buffer: a #GstBuffer
2088 * @offset: the offset to extract
2089 * @size: the size to extract
2090 * @dest: (array length=dest_size) (element-type guint8) (out): A pointer where
2091 * the destination array will be written.
2092 * @dest_size: (out): A location where the size of @dest can be written
2094 * Extracts a copy of at most @size bytes the data at @offset into a #GBytes.
2095 * @dest must be freed using g_free() when done.
2101 gst_buffer_extract_dup (GstBuffer * buffer, gsize offset, gsize size,
2102 gpointer * dest, gsize * dest_size)
2106 real_size = gst_buffer_get_size (buffer);
2108 *dest = g_malloc (MIN (real_size - offset, size));
2110 *dest_size = gst_buffer_extract (buffer, offset, *dest, size);