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.
39 * gint size, width, height, bpp;
41 * size = width * height * bpp;
42 * buffer = gst_buffer_new ();
43 * memory = gst_allocator_alloc (NULL, size, NULL);
44 * gst_buffer_insert_memory (buffer, -1, memory);
48 * Alternatively, use gst_buffer_new_allocate() to create a buffer with
49 * preallocated data of a given size.
51 * Buffers can contain a list of #GstMemory objects. You can retrieve how many
52 * memory objects with gst_buffer_n_memory() and you can get a pointer
53 * to memory with gst_buffer_peek_memory()
55 * A buffer will usually have timestamps, and a duration, but neither of these
56 * are guaranteed (they may be set to #GST_CLOCK_TIME_NONE). Whenever a
57 * meaningful value can be given for these, they should be set. The timestamps
58 * and duration are measured in nanoseconds (they are #GstClockTime values).
60 * The buffer DTS refers to the timestamp when the buffer should be decoded and
61 * is usually monotonically increasing. The buffer PTS refers to the timestamp when
62 * the buffer content should be presented to the user and is not always
63 * monotonically increasing.
65 * A buffer can also have one or both of a start and an end offset. These are
66 * media-type specific. For video buffers, the start offset will generally be
67 * the frame number. For audio buffers, it will be the number of samples
68 * produced so far. For compressed data, it could be the byte offset in a
69 * source or destination file. Likewise, the end offset will be the offset of
70 * the end of the buffer. These can only be meaningfully interpreted if you
71 * know the media type of the buffer (the preceding CAPS event). Either or both
72 * can be set to #GST_BUFFER_OFFSET_NONE.
74 * gst_buffer_ref() is used to increase the refcount of a buffer. This must be
75 * done when you want to keep a handle to the buffer after pushing it to the
76 * next element. The buffer refcount determines the writability of the buffer, a
77 * buffer is only writable when the refcount is exactly 1, i.e. when the caller
78 * has the only reference to the buffer.
80 * To efficiently create a smaller buffer out of an existing one, you can
81 * use gst_buffer_copy_region(). This method tries to share the memory objects
82 * between the two buffers.
84 * If a plug-in wants to modify the buffer data or metadata in-place, it should
85 * first obtain a buffer that is safe to modify by using
86 * gst_buffer_make_writable(). This function is optimized so that a copy will
87 * only be made when it is necessary.
89 * Several flags of the buffer can be set and unset with the
90 * GST_BUFFER_FLAG_SET() and GST_BUFFER_FLAG_UNSET() macros. Use
91 * GST_BUFFER_FLAG_IS_SET() to test if a certain #GstBufferFlags flag is set.
93 * Buffers can be efficiently merged into a larger buffer with
94 * gst_buffer_append(). Copying of memory will only be done when absolutely
97 * Arbitrary extra metadata can be set on a buffer with gst_buffer_add_meta().
98 * Metadata can be retrieved with gst_buffer_get_meta(). See also #GstMeta
100 * An element should either unref the buffer or push it out on a src pad
101 * using gst_pad_push() (see #GstPad).
103 * Buffers are usually freed by unreffing them with gst_buffer_unref(). When
104 * the refcount drops to 0, any memory and metadata pointed to by the buffer is
105 * unreffed as well. Buffers allocated from a #GstBufferPool will be returned to
106 * the pool when the refcount drops to 0.
108 * Last reviewed on 2012-03-28 (0.11.3)
110 #include "gst_private.h"
119 #include "gstbuffer.h"
120 #include "gstbufferpool.h"
122 #include "gstutils.h"
123 #include "gstversion.h"
125 GType _gst_buffer_type = 0;
127 typedef struct _GstMetaItem GstMetaItem;
134 #define ITEM_SIZE(info) ((info)->size + sizeof (GstMetaItem))
136 #define GST_BUFFER_MEM_MAX 16
138 #define GST_BUFFER_SLICE_SIZE(b) (((GstBufferImpl *)(b))->slice_size)
139 #define GST_BUFFER_MEM_LEN(b) (((GstBufferImpl *)(b))->len)
140 #define GST_BUFFER_MEM_ARRAY(b) (((GstBufferImpl *)(b))->mem)
141 #define GST_BUFFER_MEM_PTR(b,i) (((GstBufferImpl *)(b))->mem[i])
142 #define GST_BUFFER_BUFMEM(b) (((GstBufferImpl *)(b))->bufmem)
143 #define GST_BUFFER_META(b) (((GstBufferImpl *)(b))->item)
151 /* the memory blocks */
153 GstMemory *mem[GST_BUFFER_MEM_MAX];
155 /* memory of the buffer when allocated from 1 chunk */
158 /* FIXME, make metadata allocation more efficient by using part of the
165 _is_span (GstMemory ** mem, gsize len, gsize * poffset, GstMemory ** parent)
167 GstMemory *mcur, *mprv;
168 gboolean have_offset = FALSE;
173 for (i = 0; i < len; i++) {
181 /* check if memory is contiguous */
182 if (!gst_memory_is_span (mprv, mcur, &poffs))
189 *parent = mprv->parent;
199 _get_merged_memory (GstBuffer * buffer, guint idx, guint length)
201 GstMemory **mem, *result = NULL;
203 GST_CAT_LOG (GST_CAT_BUFFER, "buffer %p, idx %u, length %u", buffer, idx,
206 mem = GST_BUFFER_MEM_ARRAY (buffer);
208 if (G_UNLIKELY (length == 0)) {
210 } else if (G_LIKELY (length == 1)) {
211 result = gst_memory_ref (mem[idx]);
213 GstMemory *parent = NULL;
214 gsize size, poffset = 0;
216 size = gst_buffer_get_sizes_range (buffer, idx, length, NULL, NULL);
218 if (G_UNLIKELY (_is_span (mem + idx, length, &poffset, &parent))) {
219 if (!GST_MEMORY_IS_NO_SHARE (parent))
220 result = gst_memory_share (parent, poffset, size);
222 GST_CAT_DEBUG (GST_CAT_PERFORMANCE, "copy for merge %p", parent);
223 result = gst_memory_copy (parent, poffset, size);
226 gsize i, tocopy, left;
227 GstMapInfo sinfo, dinfo;
230 result = gst_allocator_alloc (NULL, size, NULL);
231 gst_memory_map (result, &dinfo, GST_MAP_WRITE);
236 for (i = idx; i < (idx + length) && left > 0; i++) {
237 gst_memory_map (mem[i], &sinfo, GST_MAP_READ);
238 tocopy = MIN (sinfo.size, left);
239 GST_CAT_DEBUG (GST_CAT_PERFORMANCE,
240 "memcpy %" G_GSIZE_FORMAT " bytes for merge %p from memory %p",
241 tocopy, result, mem[i]);
242 memcpy (ptr, (guint8 *) sinfo.data, tocopy);
245 gst_memory_unmap (mem[i], &sinfo);
247 gst_memory_unmap (result, &dinfo);
254 _replace_memory (GstBuffer * buffer, guint len, guint idx, guint length,
261 GST_CAT_LOG (GST_CAT_BUFFER,
262 "buffer %p replace %u-%" G_GSIZE_FORMAT " with memory %p", buffer, idx,
265 /* unref old memory */
266 for (i = idx; i < end; i++) {
267 GstMemory *old = GST_BUFFER_MEM_PTR (buffer, i);
269 gst_memory_unlock (old, GST_LOCK_FLAG_EXCLUSIVE);
270 gst_memory_unref (old);
274 /* replace with single memory */
275 gst_memory_lock (mem, GST_LOCK_FLAG_EXCLUSIVE);
276 GST_BUFFER_MEM_PTR (buffer, idx) = mem;
282 memmove (&GST_BUFFER_MEM_PTR (buffer, idx),
283 &GST_BUFFER_MEM_PTR (buffer, end), (len - end) * sizeof (gpointer));
285 GST_BUFFER_MEM_LEN (buffer) = len - length;
286 GST_BUFFER_FLAG_SET (buffer, GST_BUFFER_FLAG_TAG_MEMORY);
290 _memory_add (GstBuffer * buffer, gint idx, GstMemory * mem, gboolean lock)
292 guint i, len = GST_BUFFER_MEM_LEN (buffer);
294 GST_CAT_LOG (GST_CAT_BUFFER, "buffer %p, idx %d, mem %p, lock %d", buffer,
297 if (G_UNLIKELY (len >= GST_BUFFER_MEM_MAX)) {
298 /* too many buffer, span them. */
299 /* FIXME, there is room for improvement here: We could only try to merge
300 * 2 buffers to make some room. If we can't efficiently merge 2 buffers we
301 * could try to only merge the two smallest buffers to avoid memcpy, etc. */
302 GST_CAT_DEBUG (GST_CAT_PERFORMANCE, "memory array overflow in buffer %p",
304 _replace_memory (buffer, len, 0, len, _get_merged_memory (buffer, 0, len));
305 /* we now have 1 single spanned buffer */
312 for (i = len; i > idx; i--) {
313 /* move buffers to insert, FIXME, we need to insert first and then merge */
314 GST_BUFFER_MEM_PTR (buffer, i) = GST_BUFFER_MEM_PTR (buffer, i - 1);
316 /* and insert the new buffer */
318 gst_memory_lock (mem, GST_LOCK_FLAG_EXCLUSIVE);
319 GST_BUFFER_MEM_PTR (buffer, idx) = mem;
320 GST_BUFFER_MEM_LEN (buffer) = len + 1;
322 GST_BUFFER_FLAG_SET (buffer, GST_BUFFER_FLAG_TAG_MEMORY);
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);
523 GST_BUFFER_FLAG_UNSET (copy, GST_BUFFER_FLAG_TAG_MEMORY);
528 /* the default dispose function revives the buffer and returns it to the
529 * pool when there is a pool */
531 _gst_buffer_dispose (GstBuffer * buffer)
535 /* no pool, do free */
536 if ((pool = buffer->pool) == NULL)
539 /* keep the buffer alive */
540 gst_buffer_ref (buffer);
541 /* return the buffer to the pool */
542 GST_CAT_LOG (GST_CAT_BUFFER, "release %p to pool %p", buffer, pool);
543 gst_buffer_pool_release_buffer (pool, buffer);
549 _gst_buffer_free (GstBuffer * buffer)
551 GstMetaItem *walk, *next;
555 g_return_if_fail (buffer != NULL);
557 GST_CAT_LOG (GST_CAT_BUFFER, "finalize %p", buffer);
560 for (walk = GST_BUFFER_META (buffer); walk; walk = next) {
561 GstMeta *meta = &walk->meta;
562 const GstMetaInfo *info = meta->info;
564 /* call free_func if any */
566 info->free_func (meta, buffer);
569 /* and free the slice */
570 g_slice_free1 (ITEM_SIZE (info), walk);
573 /* get the size, when unreffing the memory, we could also unref the buffer
575 msize = GST_BUFFER_SLICE_SIZE (buffer);
577 /* free our memory */
578 len = GST_BUFFER_MEM_LEN (buffer);
579 for (i = 0; i < len; i++) {
580 gst_memory_unlock (GST_BUFFER_MEM_PTR (buffer, i), GST_LOCK_FLAG_EXCLUSIVE);
581 gst_memory_unref (GST_BUFFER_MEM_PTR (buffer, i));
584 /* we set msize to 0 when the buffer is part of the memory block */
587 memset (buffer, 0xff, msize);
589 g_slice_free1 (msize, buffer);
591 gst_memory_unref (GST_BUFFER_BUFMEM (buffer));
596 gst_buffer_init (GstBufferImpl * buffer, gsize size)
598 gst_mini_object_init (GST_MINI_OBJECT_CAST (buffer), 0, _gst_buffer_type,
599 (GstMiniObjectCopyFunction) _gst_buffer_copy,
600 (GstMiniObjectDisposeFunction) _gst_buffer_dispose,
601 (GstMiniObjectFreeFunction) _gst_buffer_free);
603 GST_BUFFER_SLICE_SIZE (buffer) = size;
605 GST_BUFFER (buffer)->pool = NULL;
606 GST_BUFFER_PTS (buffer) = GST_CLOCK_TIME_NONE;
607 GST_BUFFER_DTS (buffer) = GST_CLOCK_TIME_NONE;
608 GST_BUFFER_DURATION (buffer) = GST_CLOCK_TIME_NONE;
609 GST_BUFFER_OFFSET (buffer) = GST_BUFFER_OFFSET_NONE;
610 GST_BUFFER_OFFSET_END (buffer) = GST_BUFFER_OFFSET_NONE;
612 GST_BUFFER_MEM_LEN (buffer) = 0;
613 GST_BUFFER_META (buffer) = NULL;
619 * Creates a newly allocated buffer without any data.
623 * Returns: (transfer full): the new #GstBuffer.
626 gst_buffer_new (void)
628 GstBufferImpl *newbuf;
630 newbuf = g_slice_new (GstBufferImpl);
631 GST_CAT_LOG (GST_CAT_BUFFER, "new %p", newbuf);
633 gst_buffer_init (newbuf, sizeof (GstBufferImpl));
635 return GST_BUFFER_CAST (newbuf);
639 * gst_buffer_new_allocate:
640 * @allocator: (transfer none) (allow-none): the #GstAllocator to use, or NULL to use the
642 * @size: the size in bytes of the new buffer's data.
643 * @params: (transfer none) (allow-none): optional parameters
645 * Tries to create a newly allocated buffer with data of the given size and
646 * extra parameters from @allocator. If the requested amount of memory can't be
647 * allocated, NULL will be returned. The allocated buffer memory is not cleared.
649 * When @allocator is NULL, the default memory allocator will be used.
651 * Note that when @size == 0, the buffer will not have memory associated with it.
655 * Returns: (transfer full): a new #GstBuffer, or NULL if the memory couldn't
659 gst_buffer_new_allocate (GstAllocator * allocator, gsize size,
660 GstAllocationParams * params)
671 mem = gst_allocator_alloc (allocator, size, params);
672 if (G_UNLIKELY (mem == NULL))
678 newbuf = gst_buffer_new ();
681 _memory_add (newbuf, -1, mem, TRUE);
683 GST_CAT_LOG (GST_CAT_BUFFER,
684 "new buffer %p of size %" G_GSIZE_FORMAT " from allocator %p", newbuf,
689 asize = sizeof (GstBufferImpl) + size;
690 data = g_slice_alloc (asize);
691 if (G_UNLIKELY (data == NULL))
694 newbuf = GST_BUFFER_CAST (data);
696 gst_buffer_init ((GstBufferImpl *) data, asize);
698 mem = gst_memory_new_wrapped (0, data + sizeof (GstBufferImpl), NULL,
700 _memory_add (newbuf, -1, mem, TRUE);
705 /* allocate memory and buffer, it might be interesting to do this but there
706 * are many complications. We need to keep the memory mapped to access the
707 * buffer fields and the memory for the buffer might be just very slow. We
708 * also need to do some more magic to get the alignment right. */
709 asize = sizeof (GstBufferImpl) + size;
710 mem = gst_allocator_alloc (allocator, asize, align);
711 if (G_UNLIKELY (mem == NULL))
714 /* map the data part and init the buffer in it, set the buffer size to 0 so
715 * that a finalize won't free the buffer */
716 data = gst_memory_map (mem, &asize, NULL, GST_MAP_WRITE);
717 gst_buffer_init ((GstBufferImpl *) data, 0);
718 gst_memory_unmap (mem);
720 /* strip off the buffer */
721 gst_memory_resize (mem, sizeof (GstBufferImpl), size);
723 newbuf = GST_BUFFER_CAST (data);
724 GST_BUFFER_BUFMEM (newbuf) = mem;
727 _memory_add (newbuf, -1, gst_memory_ref (mem), TRUE);
729 GST_BUFFER_FLAG_UNSET (newbuf, GST_BUFFER_FLAG_TAG_MEMORY);
736 GST_CAT_WARNING (GST_CAT_BUFFER,
737 "failed to allocate %" G_GSIZE_FORMAT " bytes", size);
743 * gst_buffer_new_wrapped_full:
744 * @flags: #GstMemoryFlags
745 * @data: (array length=size) (element-type guint8) (transfer none): data to wrap
746 * @maxsize: allocated size of @data
747 * @offset: offset in @data
748 * @size: size of valid data
749 * @user_data: (allow-none): user_data
750 * @notify: (allow-none) (scope async) (closure user_data): called with @user_data when the memory is freed
752 * Allocate a new buffer that wraps the given memory. @data must point to
753 * @maxsize of memory, the wrapped buffer will have the region from @offset and
756 * When the buffer is destroyed, @notify will be called with @user_data.
758 * The prefix/padding must be filled with 0 if @flags contains
759 * #GST_MEMORY_FLAG_ZERO_PREFIXED and #GST_MEMORY_FLAG_ZERO_PADDED respectively.
761 * Returns: (transfer full): a new #GstBuffer
764 gst_buffer_new_wrapped_full (GstMemoryFlags flags, gpointer data,
765 gsize maxsize, gsize offset, gsize size, gpointer user_data,
766 GDestroyNotify notify)
771 newbuf = gst_buffer_new ();
773 gst_memory_new_wrapped (flags, data, maxsize, offset, size, user_data,
775 _memory_add (newbuf, -1, mem, TRUE);
776 GST_BUFFER_FLAG_UNSET (newbuf, GST_BUFFER_FLAG_TAG_MEMORY);
782 * gst_buffer_new_wrapped:
783 * @data: (array length=size) (element-type guint8) (transfer full): data to wrap
784 * @size: allocated size of @data
786 * Creates a new buffer that wraps the given @data. The memory will be freed
787 * with g_free and will be marked writable.
791 * Returns: (transfer full): a new #GstBuffer
794 gst_buffer_new_wrapped (gpointer data, gsize size)
796 return gst_buffer_new_wrapped_full (0, data, size, 0, size, data, g_free);
800 * gst_buffer_n_memory:
801 * @buffer: a #GstBuffer.
803 * Get the amount of memory blocks that this buffer has. This amount is never
804 * larger than what gst_buffer_get_max_memory() returns.
806 * Returns: (transfer full): the amount of memory block in this buffer.
809 gst_buffer_n_memory (GstBuffer * buffer)
811 g_return_val_if_fail (GST_IS_BUFFER (buffer), 0);
813 return GST_BUFFER_MEM_LEN (buffer);
817 * gst_buffer_prepend_memory:
818 * @buffer: a #GstBuffer.
819 * @mem: (transfer full): a #GstMemory.
821 * Prepend the memory block @mem to @buffer. This function takes
822 * ownership of @mem and thus doesn't increase its refcount.
824 * This function is identical to gst_buffer_insert_memory() with an index of 0.
825 * See gst_buffer_insert_memory() for more details.
828 gst_buffer_prepend_memory (GstBuffer * buffer, GstMemory * mem)
830 gst_buffer_insert_memory (buffer, 0, mem);
834 * gst_buffer_append_memory:
835 * @buffer: a #GstBuffer.
836 * @mem: (transfer full): a #GstMemory.
838 * Append the memory block @mem to @buffer. This function takes
839 * ownership of @mem and thus doesn't increase its refcount.
841 * This function is identical to gst_buffer_insert_memory() with an index of -1.
842 * See gst_buffer_insert_memory() for more details.
845 gst_buffer_append_memory (GstBuffer * buffer, GstMemory * mem)
847 gst_buffer_insert_memory (buffer, -1, mem);
851 * gst_buffer_insert_memory:
852 * @buffer: a #GstBuffer.
853 * @idx: the index to add the memory at, or -1 to append it to the end
854 * @mem: (transfer full): a #GstMemory.
856 * Insert the memory block @mem to @buffer at @idx. This function takes ownership
857 * of @mem and thus doesn't increase its refcount.
859 * Only gst_buffer_get_max_memory() can be added to a buffer. If more memory is
860 * added, existing memory blocks will automatically be merged to make room for
864 gst_buffer_insert_memory (GstBuffer * buffer, gint idx, GstMemory * mem)
866 g_return_if_fail (GST_IS_BUFFER (buffer));
867 g_return_if_fail (gst_buffer_is_writable (buffer));
868 g_return_if_fail (mem != NULL);
869 g_return_if_fail (idx == -1 ||
870 (idx >= 0 && idx <= GST_BUFFER_MEM_LEN (buffer)));
872 _memory_add (buffer, idx, mem, TRUE);
876 _get_mapped (GstBuffer * buffer, guint idx, GstMapInfo * info,
879 GstMemory *mem, *mapped;
881 mem = gst_memory_ref (GST_BUFFER_MEM_PTR (buffer, idx));
883 mapped = gst_memory_make_mapped (mem, info, flags);
886 /* memory changed, lock new memory */
887 gst_memory_lock (mapped, GST_LOCK_FLAG_EXCLUSIVE);
888 GST_BUFFER_MEM_PTR (buffer, idx) = mapped;
889 /* unlock old memory */
890 gst_memory_unlock (mem, GST_LOCK_FLAG_EXCLUSIVE);
891 GST_BUFFER_FLAG_SET (buffer, GST_BUFFER_FLAG_TAG_MEMORY);
893 gst_memory_unref (mem);
899 * gst_buffer_peek_memory:
900 * @buffer: a #GstBuffer.
903 * Get the memory block at @idx in @buffer. The memory block stays valid until
904 * the memory block in @buffer is removed, replaced or merged, typically with
905 * any call that modifies the memory in @buffer.
907 * Returns: (transfer none): the #GstMemory at @idx.
910 gst_buffer_peek_memory (GstBuffer * buffer, guint idx)
914 g_return_val_if_fail (GST_IS_BUFFER (buffer), NULL);
915 len = GST_BUFFER_MEM_LEN (buffer);
916 g_return_val_if_fail (idx < len, NULL);
918 return GST_BUFFER_MEM_PTR (buffer, idx);
922 * gst_buffer_get_memory:
923 * @buffer: a #GstBuffer.
926 * Get the memory block at index @idx in @buffer.
928 * Returns: (transfer full): a #GstMemory that contains the data of the
929 * memory block at @idx. Use gst_memory_unref () after usage.
932 gst_buffer_get_memory (GstBuffer * buffer, guint idx)
934 return gst_buffer_get_memory_range (buffer, idx, 1);
938 * gst_buffer_get_all_memory:
939 * @buffer: a #GstBuffer.
941 * Get all the memory block in @buffer. The memory blocks will be merged
942 * into one large #GstMemory.
944 * Returns: (transfer full): a #GstMemory that contains the merged memory.
945 * Use gst_memory_unref () after usage.
948 gst_buffer_get_all_memory (GstBuffer * buffer)
950 return gst_buffer_get_memory_range (buffer, 0, -1);
954 * gst_buffer_get_memory_range:
955 * @buffer: a #GstBuffer.
959 * Get @length memory blocks in @buffer starting at @idx. The memory blocks will
960 * be merged into one large #GstMemory.
962 * If @length is -1, all memory starting from @idx is merged.
964 * Returns: (transfer full): a #GstMemory that contains the merged data of @length
965 * blocks starting at @idx. Use gst_memory_unref () after usage.
968 gst_buffer_get_memory_range (GstBuffer * buffer, guint idx, gint length)
972 GST_CAT_DEBUG (GST_CAT_BUFFER, "idx %u, length %d", idx, length);
974 g_return_val_if_fail (GST_IS_BUFFER (buffer), NULL);
975 len = GST_BUFFER_MEM_LEN (buffer);
976 g_return_val_if_fail ((len == 0 && idx == 0 && length == -1) ||
977 (length == -1 && idx < len) || (length > 0 && length + idx <= len), NULL);
982 return _get_merged_memory (buffer, idx, length);
986 * gst_buffer_replace_memory:
987 * @buffer: a #GstBuffer.
989 * @mem: (transfer full): a #GstMemory
991 * Replaces the memory block at index @idx in @buffer with @mem.
994 gst_buffer_replace_memory (GstBuffer * buffer, guint idx, GstMemory * mem)
996 gst_buffer_replace_memory_range (buffer, idx, 1, mem);
1000 * gst_buffer_replace_all_memory:
1001 * @buffer: a #GstBuffer.
1002 * @mem: (transfer full): a #GstMemory
1004 * Replaces all memory in @buffer with @mem.
1007 gst_buffer_replace_all_memory (GstBuffer * buffer, GstMemory * mem)
1009 gst_buffer_replace_memory_range (buffer, 0, -1, mem);
1013 * gst_buffer_replace_memory_range:
1014 * @buffer: a #GstBuffer.
1016 * @length: a length should not be 0
1017 * @mem: (transfer full): a #GstMemory
1019 * Replaces @length memory blocks in @buffer starting at @idx with @mem.
1021 * If @length is -1, all memory starting from @idx will be removed and
1022 * replaced with @mem.
1024 * @buffer should be writable.
1027 gst_buffer_replace_memory_range (GstBuffer * buffer, guint idx, gint length,
1032 g_return_if_fail (GST_IS_BUFFER (buffer));
1033 g_return_if_fail (gst_buffer_is_writable (buffer));
1035 GST_CAT_DEBUG (GST_CAT_BUFFER, "idx %u, length %d, %p", idx, length, mem);
1037 len = GST_BUFFER_MEM_LEN (buffer);
1038 g_return_if_fail ((len == 0 && idx == 0 && length == -1) ||
1039 (length == -1 && idx < len) || (length > 0 && length + idx <= len));
1044 _replace_memory (buffer, len, idx, length, mem);
1048 * gst_buffer_remove_memory:
1049 * @buffer: a #GstBuffer.
1052 * Remove the memory block in @b at index @i.
1055 gst_buffer_remove_memory (GstBuffer * buffer, guint idx)
1057 gst_buffer_remove_memory_range (buffer, idx, 1);
1061 * gst_buffer_remove_all_memory:
1062 * @buffer: a #GstBuffer.
1064 * Remove all the memory blocks in @buffer.
1067 gst_buffer_remove_all_memory (GstBuffer * buffer)
1069 gst_buffer_remove_memory_range (buffer, 0, -1);
1073 * gst_buffer_remove_memory_range:
1074 * @buffer: a #GstBuffer.
1078 * Remove @length memory blocks in @buffer starting from @idx.
1080 * @length can be -1, in which case all memory starting from @idx is removed.
1083 gst_buffer_remove_memory_range (GstBuffer * buffer, guint idx, gint length)
1087 g_return_if_fail (GST_IS_BUFFER (buffer));
1088 g_return_if_fail (gst_buffer_is_writable (buffer));
1090 GST_CAT_DEBUG (GST_CAT_BUFFER, "idx %u, length %d", idx, length);
1092 len = GST_BUFFER_MEM_LEN (buffer);
1093 g_return_if_fail ((len == 0 && idx == 0 && length == -1) ||
1094 (length == -1 && idx < len) || length + idx <= len);
1099 _replace_memory (buffer, len, idx, length, NULL);
1103 * gst_buffer_find_memory:
1104 * @buffer: a #GstBuffer.
1105 * @offset: an offset
1107 * @idx: (out): pointer to index
1108 * @length: (out): pointer to length
1109 * @skip: (out): pointer to skip
1111 * Find the memory blocks that span @size bytes starting from @offset
1114 * When this function returns %TRUE, @idx will contain the index of the first
1115 * memory bock where the byte for @offset can be found and @length contains the
1116 * number of memory blocks containing the @size remaining bytes. @skip contains
1117 * the number of bytes to skip in the memory bock at @idx to get to the byte
1120 * @size can be -1 to get all the memory blocks after @idx.
1122 * Returns: %TRUE when @size bytes starting from @offset could be found in
1123 * @buffer and @idx, @length and @skip will be filled.
1126 gst_buffer_find_memory (GstBuffer * buffer, gsize offset, gsize size,
1127 guint * idx, guint * length, gsize * skip)
1129 guint i, len, found;
1131 g_return_val_if_fail (GST_IS_BUFFER (buffer), FALSE);
1132 g_return_val_if_fail (idx != NULL, FALSE);
1133 g_return_val_if_fail (length != NULL, FALSE);
1134 g_return_val_if_fail (skip != NULL, FALSE);
1136 len = GST_BUFFER_MEM_LEN (buffer);
1139 for (i = 0; i < len; i++) {
1143 mem = GST_BUFFER_MEM_PTR (buffer, i);
1144 s = gst_memory_get_sizes (mem, NULL, NULL);
1147 /* block before offset, or empty block, skip */
1150 /* block after offset */
1152 /* first block, remember index and offset */
1156 /* return remaining blocks */
1163 /* count the amount of found bytes */
1165 if (found >= size) {
1166 /* we have enough bytes */
1167 *length = i - *idx + 1;
1176 * gst_buffer_is_memory_range_writable:
1177 * @buffer: a #GstBuffer.
1179 * @length: a length should not be 0
1181 * Check if @length memory blocks in @buffer starting from @idx are writable.
1183 * @length can be -1 to check all the memory blocks after @idx.
1185 * Note that this function does not check if @buffer is writable, use
1186 * gst_buffer_is_writable() to check that if needed.
1188 * Returns: %TRUE if the memory range is writable
1193 gst_buffer_is_memory_range_writable (GstBuffer * buffer, guint idx, gint length)
1197 g_return_val_if_fail (GST_IS_BUFFER (buffer), FALSE);
1199 GST_CAT_DEBUG (GST_CAT_BUFFER, "idx %u, length %d", idx, length);
1201 len = GST_BUFFER_MEM_LEN (buffer);
1202 g_return_val_if_fail ((len == 0 && idx == 0 && length == -1) ||
1203 (length == -1 && idx < len) || (length > 0 && length + idx <= len),
1211 for (i = 0; i < len; i++) {
1212 if (!gst_memory_is_writable (GST_BUFFER_MEM_PTR (buffer, i + idx)))
1219 * gst_buffer_is_all_memory_writable:
1220 * @buffer: a #GstBuffer.
1222 * Check if all memory blocks in @buffer are writable.
1224 * Note that this function does not check if @buffer is writable, use
1225 * gst_buffer_is_writable() to check that if needed.
1227 * Returns: %TRUE if all memory blocks in @buffer are writable
1232 gst_buffer_is_all_memory_writable (GstBuffer * buffer)
1234 return gst_buffer_is_memory_range_writable (buffer, 0, -1);
1238 * gst_buffer_get_sizes:
1239 * @buffer: a #GstBuffer.
1240 * @offset: (out): a pointer to the offset
1241 * @maxsize: (out): a pointer to the maxsize
1243 * Get the total size of the memory blocks in @b.
1245 * When not %NULL, @offset will contain the offset of the data in the
1246 * first memory block in @buffer and @maxsize will contain the sum of
1247 * the size and @offset and the amount of extra padding on the last
1248 * memory block. @offset and @maxsize can be used to resize the
1249 * buffer memory blocks with gst_buffer_resize().
1251 * Returns: total size of the memory blocks in @buffer.
1254 gst_buffer_get_sizes (GstBuffer * buffer, gsize * offset, gsize * maxsize)
1256 return gst_buffer_get_sizes_range (buffer, 0, -1, offset, maxsize);
1260 * gst_buffer_get_size:
1261 * @buffer: a #GstBuffer.
1263 * Get the total size of the memory blocks in @buffer.
1265 * Returns: total size of the memory blocks in @buffer.
1268 gst_buffer_get_size (GstBuffer * buffer)
1270 return gst_buffer_get_sizes_range (buffer, 0, -1, NULL, NULL);
1274 * gst_buffer_get_sizes_range:
1275 * @buffer: a #GstBuffer.
1278 * @offset: (out): a pointer to the offset
1279 * @maxsize: (out): a pointer to the maxsize
1281 * Get the total size of @length memory blocks stating from @idx in @buffer.
1283 * When not %NULL, @offset will contain the offset of the data in the
1284 * memory block in @buffer at @idx and @maxsize will contain the sum of the size
1285 * and @offset and the amount of extra padding on the memory block at @idx +
1287 * @offset and @maxsize can be used to resize the buffer memory blocks with
1288 * gst_buffer_resize_range().
1290 * Returns: total size of @length memory blocks starting at @idx in @buffer.
1293 gst_buffer_get_sizes_range (GstBuffer * buffer, guint idx, gint length,
1294 gsize * offset, gsize * maxsize)
1300 g_return_val_if_fail (GST_IS_BUFFER (buffer), 0);
1301 len = GST_BUFFER_MEM_LEN (buffer);
1302 g_return_val_if_fail ((len == 0 && idx == 0 && length == -1) ||
1303 (length == -1 && idx < len) || (length + idx <= len), 0);
1308 if (G_LIKELY (length == 1)) {
1310 mem = GST_BUFFER_MEM_PTR (buffer, idx);
1311 size = gst_memory_get_sizes (mem, offset, maxsize);
1317 size = offs = extra = 0;
1318 for (i = idx; i < end; i++) {
1321 mem = GST_BUFFER_MEM_PTR (buffer, i);
1322 s = gst_memory_get_sizes (mem, &o, &ms);
1326 /* first size, take accumulated data before as the offset */
1330 /* save the amount of data after this block */
1331 extra = ms - (o + s);
1333 /* empty block, add as extra */
1340 *maxsize = offs + size + extra;
1346 * gst_buffer_resize:
1347 * @buffer: a #GstBuffer.
1348 * @offset: the offset adjustment
1349 * @size: the new size or -1 to just adjust the offset
1351 * Set the offset and total size of the memory blocks in @buffer.
1354 gst_buffer_resize (GstBuffer * buffer, gssize offset, gssize size)
1356 gst_buffer_resize_range (buffer, 0, -1, offset, size);
1360 * gst_buffer_set_size:
1361 * @buffer: a #GstBuffer.
1362 * @size: the new size
1364 * Set the total size of the memory blocks in @buffer.
1367 gst_buffer_set_size (GstBuffer * buffer, gssize size)
1369 gst_buffer_resize_range (buffer, 0, -1, 0, size);
1373 * gst_buffer_resize_range:
1374 * @buffer: a #GstBuffer.
1377 * @offset: the offset adjustment
1378 * @size: the new size or -1 to just adjust the offset
1380 * Set the total size of the @length memory blocks starting at @idx in
1383 * Returns: %TRUE if resizing succeeded, %FALSE otherwise.
1386 gst_buffer_resize_range (GstBuffer * buffer, guint idx, gint length,
1387 gssize offset, gssize size)
1390 gsize bsize, bufsize, bufoffs, bufmax;
1392 g_return_val_if_fail (gst_buffer_is_writable (buffer), FALSE);
1393 g_return_val_if_fail (size >= -1, FALSE);
1395 len = GST_BUFFER_MEM_LEN (buffer);
1396 g_return_val_if_fail ((len == 0 && idx == 0 && length == -1) ||
1397 (length == -1 && idx < len) || (length + idx <= len), FALSE);
1402 bufsize = gst_buffer_get_sizes_range (buffer, idx, length, &bufoffs, &bufmax);
1404 GST_CAT_LOG (GST_CAT_BUFFER, "trim %p %" G_GSSIZE_FORMAT "-%" G_GSSIZE_FORMAT
1405 " size:%" G_GSIZE_FORMAT " offs:%" G_GSIZE_FORMAT " max:%"
1406 G_GSIZE_FORMAT, buffer, offset, size, bufsize, bufoffs, bufmax);
1408 /* we can't go back further than the current offset or past the end of the
1410 g_return_val_if_fail ((offset < 0 && bufoffs >= -offset) || (offset >= 0
1411 && bufoffs + offset <= bufmax), FALSE);
1413 g_return_val_if_fail (bufsize >= offset, FALSE);
1414 size = bufsize - offset;
1416 g_return_val_if_fail (bufmax >= bufoffs + offset + size, FALSE);
1419 if (offset == 0 && size == bufsize)
1424 for (i = idx; i < end; i++) {
1428 mem = GST_BUFFER_MEM_PTR (buffer, i);
1429 bsize = gst_memory_get_sizes (mem, NULL, NULL);
1432 /* last buffer always gets resized to the remaining size */
1435 /* shrink buffers before the offset */
1436 else if ((gssize) bsize <= offset) {
1438 noffs = offset - bsize;
1441 /* clip other buffers */
1443 left = MIN (bsize - offset, size);
1445 if (offset != 0 || left != bsize) {
1446 if (gst_memory_is_writable (mem)) {
1447 gst_memory_resize (mem, offset, left);
1449 GstMemory *newmem = NULL;
1451 if (!GST_MEMORY_IS_NO_SHARE (mem))
1452 newmem = gst_memory_share (mem, offset, left);
1455 newmem = gst_memory_copy (mem, offset, left);
1460 gst_memory_lock (newmem, GST_LOCK_FLAG_EXCLUSIVE);
1461 GST_BUFFER_MEM_PTR (buffer, i) = newmem;
1462 gst_memory_unlock (mem, GST_LOCK_FLAG_EXCLUSIVE);
1463 gst_memory_unref (mem);
1466 GST_BUFFER_FLAG_SET (buffer, GST_BUFFER_FLAG_TAG_MEMORY);
1478 * @buffer: a #GstBuffer.
1479 * @info: (out): info about the mapping
1480 * @flags: flags for the mapping
1482 * This function fills @info with the #GstMapInfo of all merged memory
1483 * blocks in @buffer.
1485 * @flags describe the desired access of the memory. When @flags is
1486 * #GST_MAP_WRITE, @buffer should be writable (as returned from
1487 * gst_buffer_is_writable()).
1489 * When @buffer is writable but the memory isn't, a writable copy will
1490 * automatically be created and returned. The readonly copy of the
1491 * buffer memory will then also be replaced with this writable copy.
1493 * The memory in @info should be unmapped with gst_buffer_unmap() after
1496 * Returns: %TRUE if the map succeeded and @info contains valid data.
1499 gst_buffer_map (GstBuffer * buffer, GstMapInfo * info, GstMapFlags flags)
1501 return gst_buffer_map_range (buffer, 0, -1, info, flags);
1505 * gst_buffer_map_range:
1506 * @buffer: a #GstBuffer.
1509 * @info: (out): info about the mapping
1510 * @flags: flags for the mapping
1512 * This function fills @info with the #GstMapInfo of @length merged memory blocks
1513 * starting at @idx in @buffer. When @length is -1, all memory blocks starting
1514 * from @idx are merged and mapped.
1516 * @flags describe the desired access of the memory. When @flags is
1517 * #GST_MAP_WRITE, @buffer should be writable (as returned from
1518 * gst_buffer_is_writable()).
1520 * When @buffer is writable but the memory isn't, a writable copy will
1521 * automatically be created and returned. The readonly copy of the buffer memory
1522 * will then also be replaced with this writable copy.
1524 * The memory in @info should be unmapped with gst_buffer_unmap() after usage.
1526 * Returns: %TRUE if the map succeeded and @info contains valid
1530 gst_buffer_map_range (GstBuffer * buffer, guint idx, gint length,
1531 GstMapInfo * info, GstMapFlags flags)
1533 GstMemory *mem, *nmem;
1534 gboolean write, writable;
1537 g_return_val_if_fail (GST_IS_BUFFER (buffer), FALSE);
1538 g_return_val_if_fail (info != NULL, FALSE);
1539 len = GST_BUFFER_MEM_LEN (buffer);
1540 g_return_val_if_fail ((len == 0 && idx == 0 && length == -1) ||
1541 (length == -1 && idx < len) || (length > 0
1542 && length + idx <= len), FALSE);
1544 GST_CAT_LOG (GST_CAT_BUFFER, "buffer %p, idx %u, length %d, flags %04x",
1545 buffer, idx, length, flags);
1547 write = (flags & GST_MAP_WRITE) != 0;
1548 writable = gst_buffer_is_writable (buffer);
1550 /* check if we can write when asked for write access */
1551 if (G_UNLIKELY (write && !writable))
1557 mem = _get_merged_memory (buffer, idx, length);
1558 if (G_UNLIKELY (mem == NULL))
1561 /* now try to map */
1562 nmem = gst_memory_make_mapped (mem, info, flags);
1563 if (G_UNLIKELY (nmem == NULL))
1566 /* if we merged or when the map returned a different memory, we try to replace
1567 * the memory in the buffer */
1568 if (G_UNLIKELY (length > 1 || nmem != mem)) {
1569 /* if the buffer is writable, replace the memory */
1571 _replace_memory (buffer, len, idx, length, gst_memory_ref (nmem));
1574 GST_CAT_DEBUG (GST_CAT_PERFORMANCE,
1575 "temporary mapping for memory %p in buffer %p", nmem, buffer);
1584 GST_WARNING_OBJECT (buffer, "write map requested on non-writable buffer");
1585 g_critical ("write map requested on non-writable buffer");
1590 /* empty buffer, we need to return NULL */
1591 GST_DEBUG_OBJECT (buffer, "can't get buffer memory");
1592 info->memory = NULL;
1600 GST_DEBUG_OBJECT (buffer, "cannot map memory");
1607 * @buffer: a #GstBuffer.
1608 * @info: a #GstMapInfo
1610 * Release the memory previously mapped with gst_buffer_map().
1613 gst_buffer_unmap (GstBuffer * buffer, GstMapInfo * info)
1615 g_return_if_fail (GST_IS_BUFFER (buffer));
1616 g_return_if_fail (info != NULL);
1618 /* we need to check for NULL, it is possible that we tried to map a buffer
1619 * without memory and we should be able to unmap that fine */
1620 if (G_LIKELY (info->memory)) {
1621 gst_memory_unmap (info->memory, info);
1622 gst_memory_unref (info->memory);
1628 * @buffer: a #GstBuffer.
1629 * @offset: the offset to fill
1630 * @src: (array length=size) (element-type guint8): the source address
1631 * @size: the size to fill
1633 * Copy @size bytes from @src to @buffer at @offset.
1635 * Returns: The amount of bytes copied. This value can be lower than @size
1636 * when @buffer did not contain enough data.
1639 gst_buffer_fill (GstBuffer * buffer, gsize offset, gconstpointer src,
1643 const guint8 *ptr = src;
1645 g_return_val_if_fail (GST_IS_BUFFER (buffer), 0);
1646 g_return_val_if_fail (gst_buffer_is_writable (buffer), 0);
1647 g_return_val_if_fail (src != NULL || size == 0, 0);
1649 GST_CAT_LOG (GST_CAT_BUFFER,
1650 "buffer %p, offset %" G_GSIZE_FORMAT ", size %" G_GSIZE_FORMAT, buffer,
1653 len = GST_BUFFER_MEM_LEN (buffer);
1656 for (i = 0; i < len && left > 0; i++) {
1661 mem = _get_mapped (buffer, i, &info, GST_MAP_WRITE);
1662 if (info.size > offset) {
1663 /* we have enough */
1664 tocopy = MIN (info.size - offset, left);
1665 memcpy ((guint8 *) info.data + offset, ptr, tocopy);
1670 /* offset past buffer, skip */
1671 offset -= info.size;
1673 gst_memory_unmap (mem, &info);
1679 * gst_buffer_extract:
1680 * @buffer: a #GstBuffer.
1681 * @offset: the offset to extract
1682 * @dest: the destination address
1683 * @size: the size to extract
1685 * Copy @size bytes starting from @offset in @buffer to @dest.
1687 * Returns: The amount of bytes extracted. This value can be lower than @size
1688 * when @buffer did not contain enough data.
1691 gst_buffer_extract (GstBuffer * buffer, gsize offset, gpointer dest, gsize size)
1696 g_return_val_if_fail (GST_IS_BUFFER (buffer), 0);
1697 g_return_val_if_fail (dest != NULL, 0);
1699 GST_CAT_LOG (GST_CAT_BUFFER,
1700 "buffer %p, offset %" G_GSIZE_FORMAT ", size %" G_GSIZE_FORMAT, buffer,
1703 len = GST_BUFFER_MEM_LEN (buffer);
1706 for (i = 0; i < len && left > 0; i++) {
1711 mem = _get_mapped (buffer, i, &info, GST_MAP_READ);
1712 if (info.size > offset) {
1713 /* we have enough */
1714 tocopy = MIN (info.size - offset, left);
1715 memcpy (ptr, (guint8 *) info.data + offset, tocopy);
1720 /* offset past buffer, skip */
1721 offset -= info.size;
1723 gst_memory_unmap (mem, &info);
1729 * gst_buffer_memcmp:
1730 * @buffer: a #GstBuffer.
1731 * @offset: the offset in @buffer
1732 * @mem: (array length=size) (element-type guint8): the memory to compare
1733 * @size: the size to compare
1735 * Compare @size bytes starting from @offset in @buffer with the memory in @mem.
1737 * Returns: 0 if the memory is equal.
1740 gst_buffer_memcmp (GstBuffer * buffer, gsize offset, gconstpointer mem,
1744 const guint8 *ptr = mem;
1747 g_return_val_if_fail (GST_IS_BUFFER (buffer), 0);
1748 g_return_val_if_fail (mem != NULL, 0);
1750 GST_CAT_LOG (GST_CAT_BUFFER,
1751 "buffer %p, offset %" G_GSIZE_FORMAT ", size %" G_GSIZE_FORMAT, buffer,
1754 if (G_UNLIKELY (gst_buffer_get_size (buffer) < offset + size))
1757 len = GST_BUFFER_MEM_LEN (buffer);
1759 for (i = 0; i < len && size > 0 && res == 0; i++) {
1764 mem = _get_mapped (buffer, i, &info, GST_MAP_READ);
1765 if (info.size > offset) {
1766 /* we have enough */
1767 tocmp = MIN (info.size - offset, size);
1768 res = memcmp (ptr, (guint8 *) info.data + offset, tocmp);
1773 /* offset past buffer, skip */
1774 offset -= info.size;
1776 gst_memory_unmap (mem, &info);
1782 * gst_buffer_memset:
1783 * @buffer: a #GstBuffer.
1784 * @offset: the offset in @buffer
1785 * @val: the value to set
1786 * @size: the size to set
1788 * Fill @buf with @size bytes with @val starting from @offset.
1790 * Returns: The amount of bytes filled. This value can be lower than @size
1791 * when @buffer did not contain enough data.
1794 gst_buffer_memset (GstBuffer * buffer, gsize offset, guint8 val, gsize size)
1798 g_return_val_if_fail (GST_IS_BUFFER (buffer), 0);
1799 g_return_val_if_fail (gst_buffer_is_writable (buffer), 0);
1801 GST_CAT_LOG (GST_CAT_BUFFER,
1802 "buffer %p, offset %" G_GSIZE_FORMAT ", val %02x, size %" G_GSIZE_FORMAT,
1803 buffer, offset, val, size);
1805 len = GST_BUFFER_MEM_LEN (buffer);
1808 for (i = 0; i < len && left > 0; i++) {
1813 mem = _get_mapped (buffer, i, &info, GST_MAP_WRITE);
1814 if (info.size > offset) {
1815 /* we have enough */
1816 toset = MIN (info.size - offset, left);
1817 memset ((guint8 *) info.data + offset, val, toset);
1821 /* offset past buffer, skip */
1822 offset -= info.size;
1824 gst_memory_unmap (mem, &info);
1830 * gst_buffer_copy_region:
1831 * @parent: a #GstBuffer.
1832 * @flags: the #GstBufferCopyFlags
1833 * @offset: the offset into parent #GstBuffer at which the new sub-buffer
1835 * @size: the size of the new #GstBuffer sub-buffer, in bytes.
1837 * Creates a sub-buffer from @parent at @offset and @size.
1838 * This sub-buffer uses the actual memory space of the parent buffer.
1839 * This function will copy the offset and timestamp fields when the
1840 * offset is 0. If not, they will be set to #GST_CLOCK_TIME_NONE and
1841 * #GST_BUFFER_OFFSET_NONE.
1842 * If @offset equals 0 and @size equals the total size of @buffer, the
1843 * duration and offset end fields are also copied. If not they will be set
1844 * to #GST_CLOCK_TIME_NONE and #GST_BUFFER_OFFSET_NONE.
1848 * Returns: (transfer full): the new #GstBuffer or NULL if the arguments were
1852 gst_buffer_copy_region (GstBuffer * buffer, GstBufferCopyFlags flags,
1853 gsize offset, gsize size)
1857 g_return_val_if_fail (buffer != NULL, NULL);
1859 /* create the new buffer */
1860 copy = gst_buffer_new ();
1862 GST_CAT_LOG (GST_CAT_BUFFER, "new region copy %p of %p %" G_GSIZE_FORMAT
1863 "-%" G_GSIZE_FORMAT, copy, buffer, offset, size);
1865 if (!gst_buffer_copy_into (copy, buffer, flags, offset, size))
1866 gst_buffer_replace (©, NULL);
1872 * gst_buffer_append:
1873 * @buf1: (transfer full): the first source #GstBuffer to append.
1874 * @buf2: (transfer full): the second source #GstBuffer to append.
1876 * Append all the memory from @buf2 to @buf1. The result buffer will contain a
1877 * concatenation of the memory of @buf1 and @buf2.
1879 * Returns: (transfer full): the new #GstBuffer that contains the memory
1880 * of the two source buffers.
1883 gst_buffer_append (GstBuffer * buf1, GstBuffer * buf2)
1885 return gst_buffer_append_region (buf1, buf2, 0, -1);
1889 * gst_buffer_append_region:
1890 * @buf1: (transfer full): the first source #GstBuffer to append.
1891 * @buf2: (transfer full): the second source #GstBuffer to append.
1892 * @offset: the offset in @buf2
1893 * @size: the size or -1 of @buf2
1895 * Append @size bytes at @offset from @buf2 to @buf1. The result buffer will
1896 * contain a concatenation of the memory of @buf1 and the requested region of
1899 * Returns: (transfer full): the new #GstBuffer that contains the memory
1900 * of the two source buffers.
1903 gst_buffer_append_region (GstBuffer * buf1, GstBuffer * buf2, gssize offset,
1908 g_return_val_if_fail (GST_IS_BUFFER (buf1), NULL);
1909 g_return_val_if_fail (GST_IS_BUFFER (buf2), NULL);
1911 buf1 = gst_buffer_make_writable (buf1);
1912 buf2 = gst_buffer_make_writable (buf2);
1914 gst_buffer_resize (buf2, offset, size);
1916 len = GST_BUFFER_MEM_LEN (buf2);
1917 for (i = 0; i < len; i++) {
1920 mem = GST_BUFFER_MEM_PTR (buf2, i);
1921 GST_BUFFER_MEM_PTR (buf2, i) = NULL;
1922 _memory_add (buf1, -1, mem, FALSE);
1925 GST_BUFFER_MEM_LEN (buf2) = 0;
1926 GST_BUFFER_FLAG_SET (buf2, GST_BUFFER_FLAG_TAG_MEMORY);
1927 gst_buffer_unref (buf2);
1933 * gst_buffer_get_meta:
1934 * @buffer: a #GstBuffer
1935 * @api: the #GType of an API
1937 * Get the metadata for @api on buffer. When there is no such
1938 * metadata, NULL is returned.
1940 * Returns: (transfer none): the metadata for @api on @buffer.
1943 gst_buffer_get_meta (GstBuffer * buffer, GType api)
1946 GstMeta *result = NULL;
1948 g_return_val_if_fail (buffer != NULL, NULL);
1949 g_return_val_if_fail (api != 0, NULL);
1951 /* find GstMeta of the requested API */
1952 for (item = GST_BUFFER_META (buffer); item; item = item->next) {
1953 GstMeta *meta = &item->meta;
1954 if (meta->info->api == api) {
1963 * gst_buffer_add_meta:
1964 * @buffer: a #GstBuffer
1965 * @info: a #GstMetaInfo
1966 * @params: params for @info
1968 * Add metadata for @info to @buffer using the parameters in @params.
1970 * Returns: (transfer none): the metadata for the api in @info on @buffer.
1973 gst_buffer_add_meta (GstBuffer * buffer, const GstMetaInfo * info,
1977 GstMeta *result = NULL;
1980 g_return_val_if_fail (buffer != NULL, NULL);
1981 g_return_val_if_fail (info != NULL, NULL);
1982 g_return_val_if_fail (gst_buffer_is_writable (buffer), NULL);
1984 /* create a new slice */
1985 size = ITEM_SIZE (info);
1986 item = g_slice_alloc (size);
1987 result = &item->meta;
1988 result->info = info;
1989 result->flags = GST_META_FLAG_NONE;
1991 GST_CAT_DEBUG (GST_CAT_BUFFER,
1992 "alloc metadata %p (%s) of size %" G_GSIZE_FORMAT, result,
1993 g_type_name (info->type), info->size);
1995 /* call the init_func when needed */
1996 if (info->init_func)
1997 if (!info->init_func (result, params, buffer))
2000 /* and add to the list of metadata */
2001 item->next = GST_BUFFER_META (buffer);
2002 GST_BUFFER_META (buffer) = item;
2008 g_slice_free1 (size, item);
2014 * gst_buffer_remove_meta:
2015 * @buffer: a #GstBuffer
2018 * Remove the metadata for @meta on @buffer.
2020 * Returns: %TRUE if the metadata existed and was removed, %FALSE if no such
2021 * metadata was on @buffer.
2024 gst_buffer_remove_meta (GstBuffer * buffer, GstMeta * meta)
2026 GstMetaItem *walk, *prev;
2028 g_return_val_if_fail (buffer != NULL, FALSE);
2029 g_return_val_if_fail (meta != NULL, FALSE);
2030 g_return_val_if_fail (gst_buffer_is_writable (buffer), FALSE);
2031 g_return_val_if_fail (!GST_META_FLAG_IS_SET (meta, GST_META_FLAG_LOCKED),
2034 /* find the metadata and delete */
2035 prev = GST_BUFFER_META (buffer);
2036 for (walk = prev; walk; walk = walk->next) {
2037 GstMeta *m = &walk->meta;
2039 const GstMetaInfo *info = meta->info;
2041 /* remove from list */
2042 if (GST_BUFFER_META (buffer) == walk)
2043 GST_BUFFER_META (buffer) = walk->next;
2045 prev->next = walk->next;
2046 /* call free_func if any */
2047 if (info->free_func)
2048 info->free_func (m, buffer);
2050 /* and free the slice */
2051 g_slice_free1 (ITEM_SIZE (info), walk);
2056 return walk != NULL;
2060 * gst_buffer_iterate_meta:
2061 * @buffer: a #GstBuffer
2062 * @state: an opaque state pointer
2064 * Retrieve the next #GstMeta after @current. If @state points
2065 * to %NULL, the first metadata is returned.
2067 * @state will be updated with an opaque state pointer
2069 * Returns: (transfer none): The next #GstMeta or %NULL when there are
2073 gst_buffer_iterate_meta (GstBuffer * buffer, gpointer * state)
2077 g_return_val_if_fail (buffer != NULL, NULL);
2078 g_return_val_if_fail (state != NULL, NULL);
2080 meta = (GstMetaItem **) state;
2082 /* state NULL, move to first item */
2083 *meta = GST_BUFFER_META (buffer);
2085 /* state !NULL, move to next item in list */
2086 *meta = (*meta)->next;
2089 return &(*meta)->meta;
2095 * gst_buffer_foreach_meta:
2096 * @buffer: a #GstBuffer
2097 * @func: (scope call): a #GstBufferForeachMetaFunc to call
2098 * @user_data: (closure): user data passed to @func
2100 * Call @func with @user_data for each meta in @buffer.
2102 * @func can modify the passed meta pointer or its contents. The return value
2103 * of @func define if this function returns or if the remaining metadata items
2104 * in the buffer should be skipped.
2106 * Returns: %FALSE when @func returned %FALSE for one of the metadata.
2109 gst_buffer_foreach_meta (GstBuffer * buffer, GstBufferForeachMetaFunc func,
2112 GstMetaItem *walk, *prev, *next;
2113 gboolean res = TRUE;
2115 g_return_val_if_fail (buffer != NULL, FALSE);
2116 g_return_val_if_fail (func != NULL, FALSE);
2118 /* find the metadata and delete */
2119 prev = GST_BUFFER_META (buffer);
2120 for (walk = prev; walk; walk = next) {
2123 m = new = &walk->meta;
2126 res = func (buffer, &new, user_data);
2129 const GstMetaInfo *info = m->info;
2131 GST_CAT_DEBUG (GST_CAT_BUFFER, "remove metadata %p (%s)", m,
2132 g_type_name (info->type));
2134 g_return_val_if_fail (gst_buffer_is_writable (buffer), FALSE);
2135 g_return_val_if_fail (!GST_META_FLAG_IS_SET (m, GST_META_FLAG_LOCKED),
2138 /* remove from list */
2139 if (GST_BUFFER_META (buffer) == walk)
2140 GST_BUFFER_META (buffer) = next;
2144 /* call free_func if any */
2145 if (info->free_func)
2146 info->free_func (m, buffer);
2148 /* and free the slice */
2149 g_slice_free1 (ITEM_SIZE (info), walk);
2158 * gst_buffer_extract_dup:
2159 * @buffer: a #GstBuffer
2160 * @offset: the offset to extract
2161 * @size: the size to extract
2162 * @dest: (array length=dest_size) (element-type guint8) (out): A pointer where
2163 * the destination array will be written.
2164 * @dest_size: (out): A location where the size of @dest can be written
2166 * Extracts a copy of at most @size bytes the data at @offset into a #GBytes.
2167 * @dest must be freed using g_free() when done.
2173 gst_buffer_extract_dup (GstBuffer * buffer, gsize offset, gsize size,
2174 gpointer * dest, gsize * dest_size)
2178 real_size = gst_buffer_get_size (buffer);
2180 *dest = g_malloc (MIN (real_size - offset, size));
2182 *dest_size = gst_buffer_extract (buffer, offset, *dest, size);