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 #include "gst_private.h"
117 #include "gstbuffer.h"
118 #include "gstbufferpool.h"
120 #include "gstutils.h"
121 #include "gstversion.h"
123 GType _gst_buffer_type = 0;
125 typedef struct _GstMetaItem GstMetaItem;
132 #define ITEM_SIZE(info) ((info)->size + sizeof (GstMetaItem))
134 #define GST_BUFFER_MEM_MAX 16
136 #define GST_BUFFER_SLICE_SIZE(b) (((GstBufferImpl *)(b))->slice_size)
137 #define GST_BUFFER_MEM_LEN(b) (((GstBufferImpl *)(b))->len)
138 #define GST_BUFFER_MEM_ARRAY(b) (((GstBufferImpl *)(b))->mem)
139 #define GST_BUFFER_MEM_PTR(b,i) (((GstBufferImpl *)(b))->mem[i])
140 #define GST_BUFFER_BUFMEM(b) (((GstBufferImpl *)(b))->bufmem)
141 #define GST_BUFFER_META(b) (((GstBufferImpl *)(b))->item)
149 /* the memory blocks */
151 GstMemory *mem[GST_BUFFER_MEM_MAX];
153 /* memory of the buffer when allocated from 1 chunk */
156 /* FIXME, make metadata allocation more efficient by using part of the
163 _is_span (GstMemory ** mem, gsize len, gsize * poffset, GstMemory ** parent)
165 GstMemory *mcur, *mprv;
166 gboolean have_offset = FALSE;
171 for (i = 0; i < len; i++) {
179 /* check if memory is contiguous */
180 if (!gst_memory_is_span (mprv, mcur, &poffs))
187 *parent = mprv->parent;
197 _get_merged_memory (GstBuffer * buffer, guint idx, guint length)
199 GstMemory **mem, *result = NULL;
201 GST_CAT_LOG (GST_CAT_BUFFER, "buffer %p, idx %u, length %u", buffer, idx,
204 mem = GST_BUFFER_MEM_ARRAY (buffer);
206 if (G_UNLIKELY (length == 0)) {
208 } else if (G_LIKELY (length == 1)) {
209 result = gst_memory_ref (mem[idx]);
211 GstMemory *parent = NULL;
212 gsize size, poffset = 0;
214 size = gst_buffer_get_sizes_range (buffer, idx, length, NULL, NULL);
216 if (G_UNLIKELY (_is_span (mem + idx, length, &poffset, &parent))) {
217 if (!GST_MEMORY_IS_NO_SHARE (parent))
218 result = gst_memory_share (parent, poffset, size);
220 GST_CAT_DEBUG (GST_CAT_PERFORMANCE, "copy for merge %p", parent);
221 result = gst_memory_copy (parent, poffset, size);
224 gsize i, tocopy, left;
225 GstMapInfo sinfo, dinfo;
228 result = gst_allocator_alloc (NULL, size, NULL);
229 gst_memory_map (result, &dinfo, GST_MAP_WRITE);
234 for (i = idx; i < (idx + length) && left > 0; i++) {
235 gst_memory_map (mem[i], &sinfo, GST_MAP_READ);
236 tocopy = MIN (sinfo.size, left);
237 GST_CAT_DEBUG (GST_CAT_PERFORMANCE,
238 "memcpy %" G_GSIZE_FORMAT " bytes for merge %p from memory %p",
239 tocopy, result, mem[i]);
240 memcpy (ptr, (guint8 *) sinfo.data, tocopy);
243 gst_memory_unmap (mem[i], &sinfo);
245 gst_memory_unmap (result, &dinfo);
252 _replace_memory (GstBuffer * buffer, guint len, guint idx, guint length,
259 GST_CAT_LOG (GST_CAT_BUFFER,
260 "buffer %p replace %u-%" G_GSIZE_FORMAT " with memory %p", buffer, idx,
263 /* unref old memory */
264 for (i = idx; i < end; i++) {
265 GstMemory *old = GST_BUFFER_MEM_PTR (buffer, i);
267 gst_memory_unlock (old, GST_LOCK_FLAG_EXCLUSIVE);
268 gst_memory_unref (old);
272 /* replace with single memory */
273 gst_memory_lock (mem, GST_LOCK_FLAG_EXCLUSIVE);
274 GST_BUFFER_MEM_PTR (buffer, idx) = mem;
280 memmove (&GST_BUFFER_MEM_PTR (buffer, idx),
281 &GST_BUFFER_MEM_PTR (buffer, end), (len - end) * sizeof (gpointer));
283 GST_BUFFER_MEM_LEN (buffer) = len - length;
284 GST_BUFFER_FLAG_SET (buffer, GST_BUFFER_FLAG_TAG_MEMORY);
288 _memory_add (GstBuffer * buffer, gint idx, GstMemory * mem, gboolean lock)
290 guint i, len = GST_BUFFER_MEM_LEN (buffer);
292 GST_CAT_LOG (GST_CAT_BUFFER, "buffer %p, idx %d, mem %p, lock %d", buffer,
295 if (G_UNLIKELY (len >= GST_BUFFER_MEM_MAX)) {
296 /* too many buffer, span them. */
297 /* FIXME, there is room for improvement here: We could only try to merge
298 * 2 buffers to make some room. If we can't efficiently merge 2 buffers we
299 * could try to only merge the two smallest buffers to avoid memcpy, etc. */
300 GST_CAT_DEBUG (GST_CAT_PERFORMANCE, "memory array overflow in buffer %p",
302 _replace_memory (buffer, len, 0, len, _get_merged_memory (buffer, 0, len));
303 /* we now have 1 single spanned buffer */
310 for (i = len; i > idx; i--) {
311 /* move buffers to insert, FIXME, we need to insert first and then merge */
312 GST_BUFFER_MEM_PTR (buffer, i) = GST_BUFFER_MEM_PTR (buffer, i - 1);
314 /* and insert the new buffer */
316 gst_memory_lock (mem, GST_LOCK_FLAG_EXCLUSIVE);
317 GST_BUFFER_MEM_PTR (buffer, idx) = mem;
318 GST_BUFFER_MEM_LEN (buffer) = len + 1;
320 GST_BUFFER_FLAG_SET (buffer, GST_BUFFER_FLAG_TAG_MEMORY);
323 GST_DEFINE_MINI_OBJECT_TYPE (GstBuffer, gst_buffer);
326 _priv_gst_buffer_initialize (void)
328 _gst_buffer_type = gst_buffer_get_type ();
332 * gst_buffer_get_max_memory:
334 * Get the maximum amount of memory blocks that a buffer can hold. This is a
335 * compile time constant that can be queried with the function.
337 * When more memory blocks are added, existing memory blocks will be merged
338 * together to make room for the new block.
340 * Returns: the maximum amount of memory blocks that a buffer can hold.
345 gst_buffer_get_max_memory (void)
347 return GST_BUFFER_MEM_MAX;
351 * gst_buffer_copy_into:
352 * @dest: a destination #GstBuffer
353 * @src: a source #GstBuffer
354 * @flags: flags indicating what metadata fields should be copied.
355 * @offset: offset to copy from
356 * @size: total size to copy. If -1, all data is copied.
358 * Copies the information from @src into @dest.
360 * If @dest already contains memory and @flags contains GST_BUFFER_COPY_MEMORY,
361 * the memory from @src will be appended to @dest.
363 * @flags indicate which fields will be copied.
365 * Returns: %TRUE if the copying succeeded, %FALSE otherwise.
368 gst_buffer_copy_into (GstBuffer * dest, GstBuffer * src,
369 GstBufferCopyFlags flags, gsize offset, gsize size)
373 gboolean region = FALSE;
375 g_return_val_if_fail (dest != NULL, FALSE);
376 g_return_val_if_fail (src != NULL, FALSE);
378 /* nothing to copy if the buffers are the same */
379 if (G_UNLIKELY (dest == src))
382 g_return_val_if_fail (gst_buffer_is_writable (dest), FALSE);
384 bufsize = gst_buffer_get_size (src);
385 g_return_val_if_fail (bufsize >= offset, FALSE);
389 size = bufsize - offset;
392 g_return_val_if_fail (bufsize >= offset + size, FALSE);
394 GST_CAT_LOG (GST_CAT_BUFFER, "copy %p to %p, offset %" G_GSIZE_FORMAT
395 "-%" G_GSIZE_FORMAT "/%" G_GSIZE_FORMAT, src, dest, offset, size,
398 if (flags & GST_BUFFER_COPY_FLAGS) {
400 GST_MINI_OBJECT_FLAGS (dest) = GST_MINI_OBJECT_FLAGS (src);
403 if (flags & GST_BUFFER_COPY_TIMESTAMPS) {
405 GST_BUFFER_PTS (dest) = GST_BUFFER_PTS (src);
406 GST_BUFFER_DTS (dest) = GST_BUFFER_DTS (src);
407 GST_BUFFER_OFFSET (dest) = GST_BUFFER_OFFSET (src);
408 if (size == bufsize) {
409 GST_BUFFER_DURATION (dest) = GST_BUFFER_DURATION (src);
410 GST_BUFFER_OFFSET_END (dest) = GST_BUFFER_OFFSET_END (src);
413 GST_BUFFER_PTS (dest) = GST_CLOCK_TIME_NONE;
414 GST_BUFFER_DTS (dest) = GST_CLOCK_TIME_NONE;
415 GST_BUFFER_DURATION (dest) = GST_CLOCK_TIME_NONE;
416 GST_BUFFER_OFFSET (dest) = GST_BUFFER_OFFSET_NONE;
417 GST_BUFFER_OFFSET_END (dest) = GST_BUFFER_OFFSET_NONE;
421 if (flags & GST_BUFFER_COPY_MEMORY) {
422 gsize skip, left, len, dest_len, i, bsize;
425 deep = flags & GST_BUFFER_COPY_DEEP;
427 len = GST_BUFFER_MEM_LEN (src);
428 dest_len = GST_BUFFER_MEM_LEN (dest);
432 /* copy and make regions of the memory */
433 for (i = 0; i < len && left > 0; i++) {
434 GstMemory *mem = GST_BUFFER_MEM_PTR (src, i);
436 bsize = gst_memory_get_sizes (mem, NULL, NULL);
439 /* don't copy buffer */
442 GstMemory *newmem = NULL;
445 tocopy = MIN (bsize - skip, left);
447 if (tocopy < bsize && !deep && !GST_MEMORY_IS_NO_SHARE (mem)) {
448 /* we need to clip something */
449 newmem = gst_memory_share (mem, skip, tocopy);
454 if (deep || GST_MEMORY_IS_NO_SHARE (mem) || (!newmem && tocopy < bsize)) {
455 /* deep copy or we're not allowed to share this memory
456 * between buffers, always copy then */
457 newmem = gst_memory_copy (mem, skip, tocopy);
459 } else if (!newmem) {
460 newmem = gst_memory_ref (mem);
464 gst_buffer_remove_memory_range (dest, dest_len, -1);
468 _memory_add (dest, -1, newmem, TRUE);
472 if (flags & GST_BUFFER_COPY_MERGE) {
475 len = GST_BUFFER_MEM_LEN (dest);
476 mem = _get_merged_memory (dest, 0, len);
478 gst_buffer_remove_memory_range (dest, dest_len, -1);
481 _replace_memory (dest, len, 0, len, mem);
485 if (flags & GST_BUFFER_COPY_META) {
486 for (walk = GST_BUFFER_META (src); walk; walk = walk->next) {
487 GstMeta *meta = &walk->meta;
488 const GstMetaInfo *info = meta->info;
490 if (info->transform_func) {
491 GstMetaTransformCopy copy_data;
493 copy_data.region = region;
494 copy_data.offset = offset;
495 copy_data.size = size;
497 info->transform_func (dest, meta, src,
498 _gst_meta_transform_copy, ©_data);
507 _gst_buffer_copy (GstBuffer * buffer)
511 g_return_val_if_fail (buffer != NULL, NULL);
513 /* create a fresh new buffer */
514 copy = gst_buffer_new ();
516 /* we simply copy everything from our parent */
517 if (!gst_buffer_copy_into (copy, buffer, GST_BUFFER_COPY_ALL, 0, -1))
518 gst_buffer_replace (©, NULL);
521 GST_BUFFER_FLAG_UNSET (copy, GST_BUFFER_FLAG_TAG_MEMORY);
526 /* the default dispose function revives the buffer and returns it to the
527 * pool when there is a pool */
529 _gst_buffer_dispose (GstBuffer * buffer)
533 /* no pool, do free */
534 if ((pool = buffer->pool) == NULL)
537 /* keep the buffer alive */
538 gst_buffer_ref (buffer);
539 /* return the buffer to the pool */
540 GST_CAT_LOG (GST_CAT_BUFFER, "release %p to pool %p", buffer, pool);
541 gst_buffer_pool_release_buffer (pool, buffer);
547 _gst_buffer_free (GstBuffer * buffer)
549 GstMetaItem *walk, *next;
553 g_return_if_fail (buffer != NULL);
555 GST_CAT_LOG (GST_CAT_BUFFER, "finalize %p", buffer);
558 for (walk = GST_BUFFER_META (buffer); walk; walk = next) {
559 GstMeta *meta = &walk->meta;
560 const GstMetaInfo *info = meta->info;
562 /* call free_func if any */
564 info->free_func (meta, buffer);
567 /* and free the slice */
568 g_slice_free1 (ITEM_SIZE (info), walk);
571 /* get the size, when unreffing the memory, we could also unref the buffer
573 msize = GST_BUFFER_SLICE_SIZE (buffer);
575 /* free our memory */
576 len = GST_BUFFER_MEM_LEN (buffer);
577 for (i = 0; i < len; i++) {
578 gst_memory_unlock (GST_BUFFER_MEM_PTR (buffer, i), GST_LOCK_FLAG_EXCLUSIVE);
579 gst_memory_unref (GST_BUFFER_MEM_PTR (buffer, i));
582 /* we set msize to 0 when the buffer is part of the memory block */
585 memset (buffer, 0xff, msize);
587 g_slice_free1 (msize, buffer);
589 gst_memory_unref (GST_BUFFER_BUFMEM (buffer));
594 gst_buffer_init (GstBufferImpl * buffer, gsize size)
596 gst_mini_object_init (GST_MINI_OBJECT_CAST (buffer), 0, _gst_buffer_type,
597 (GstMiniObjectCopyFunction) _gst_buffer_copy,
598 (GstMiniObjectDisposeFunction) _gst_buffer_dispose,
599 (GstMiniObjectFreeFunction) _gst_buffer_free);
601 GST_BUFFER_SLICE_SIZE (buffer) = size;
603 GST_BUFFER (buffer)->pool = NULL;
604 GST_BUFFER_PTS (buffer) = GST_CLOCK_TIME_NONE;
605 GST_BUFFER_DTS (buffer) = GST_CLOCK_TIME_NONE;
606 GST_BUFFER_DURATION (buffer) = GST_CLOCK_TIME_NONE;
607 GST_BUFFER_OFFSET (buffer) = GST_BUFFER_OFFSET_NONE;
608 GST_BUFFER_OFFSET_END (buffer) = GST_BUFFER_OFFSET_NONE;
610 GST_BUFFER_MEM_LEN (buffer) = 0;
611 GST_BUFFER_META (buffer) = NULL;
617 * Creates a newly allocated buffer without any data.
621 * Returns: (transfer full): the new #GstBuffer.
624 gst_buffer_new (void)
626 GstBufferImpl *newbuf;
628 newbuf = g_slice_new (GstBufferImpl);
629 GST_CAT_LOG (GST_CAT_BUFFER, "new %p", newbuf);
631 gst_buffer_init (newbuf, sizeof (GstBufferImpl));
633 return GST_BUFFER_CAST (newbuf);
637 * gst_buffer_new_allocate:
638 * @allocator: (transfer none) (allow-none): the #GstAllocator to use, or NULL to use the
640 * @size: the size in bytes of the new buffer's data.
641 * @params: (transfer none) (allow-none): optional parameters
643 * Tries to create a newly allocated buffer with data of the given size and
644 * extra parameters from @allocator. If the requested amount of memory can't be
645 * allocated, NULL will be returned. The allocated buffer memory is not cleared.
647 * When @allocator is NULL, the default memory allocator will be used.
649 * Note that when @size == 0, the buffer will not have memory associated with it.
653 * Returns: (transfer full): a new #GstBuffer, or NULL if the memory couldn't
657 gst_buffer_new_allocate (GstAllocator * allocator, gsize size,
658 GstAllocationParams * params)
669 mem = gst_allocator_alloc (allocator, size, params);
670 if (G_UNLIKELY (mem == NULL))
676 newbuf = gst_buffer_new ();
679 _memory_add (newbuf, -1, mem, TRUE);
681 GST_CAT_LOG (GST_CAT_BUFFER,
682 "new buffer %p of size %" G_GSIZE_FORMAT " from allocator %p", newbuf,
687 asize = sizeof (GstBufferImpl) + size;
688 data = g_slice_alloc (asize);
689 if (G_UNLIKELY (data == NULL))
692 newbuf = GST_BUFFER_CAST (data);
694 gst_buffer_init ((GstBufferImpl *) data, asize);
696 mem = gst_memory_new_wrapped (0, data + sizeof (GstBufferImpl), NULL,
698 _memory_add (newbuf, -1, mem, TRUE);
703 /* allocate memory and buffer, it might be interesting to do this but there
704 * are many complications. We need to keep the memory mapped to access the
705 * buffer fields and the memory for the buffer might be just very slow. We
706 * also need to do some more magic to get the alignment right. */
707 asize = sizeof (GstBufferImpl) + size;
708 mem = gst_allocator_alloc (allocator, asize, align);
709 if (G_UNLIKELY (mem == NULL))
712 /* map the data part and init the buffer in it, set the buffer size to 0 so
713 * that a finalize won't free the buffer */
714 data = gst_memory_map (mem, &asize, NULL, GST_MAP_WRITE);
715 gst_buffer_init ((GstBufferImpl *) data, 0);
716 gst_memory_unmap (mem);
718 /* strip off the buffer */
719 gst_memory_resize (mem, sizeof (GstBufferImpl), size);
721 newbuf = GST_BUFFER_CAST (data);
722 GST_BUFFER_BUFMEM (newbuf) = mem;
725 _memory_add (newbuf, -1, gst_memory_ref (mem), TRUE);
727 GST_BUFFER_FLAG_UNSET (newbuf, GST_BUFFER_FLAG_TAG_MEMORY);
734 GST_CAT_WARNING (GST_CAT_BUFFER,
735 "failed to allocate %" G_GSIZE_FORMAT " bytes", size);
741 * gst_buffer_new_wrapped_full:
742 * @flags: #GstMemoryFlags
743 * @data: (array length=size) (element-type guint8) (transfer none): data to wrap
744 * @maxsize: allocated size of @data
745 * @offset: offset in @data
746 * @size: size of valid data
747 * @user_data: (allow-none): user_data
748 * @notify: (allow-none) (scope async) (closure user_data): called with @user_data when the memory is freed
750 * Allocate a new buffer that wraps the given memory. @data must point to
751 * @maxsize of memory, the wrapped buffer will have the region from @offset and
754 * When the buffer is destroyed, @notify will be called with @user_data.
756 * The prefix/padding must be filled with 0 if @flags contains
757 * #GST_MEMORY_FLAG_ZERO_PREFIXED and #GST_MEMORY_FLAG_ZERO_PADDED respectively.
759 * Returns: (transfer full): a new #GstBuffer
762 gst_buffer_new_wrapped_full (GstMemoryFlags flags, gpointer data,
763 gsize maxsize, gsize offset, gsize size, gpointer user_data,
764 GDestroyNotify notify)
769 newbuf = gst_buffer_new ();
771 gst_memory_new_wrapped (flags, data, maxsize, offset, size, user_data,
773 _memory_add (newbuf, -1, mem, TRUE);
774 GST_BUFFER_FLAG_UNSET (newbuf, GST_BUFFER_FLAG_TAG_MEMORY);
780 * gst_buffer_new_wrapped:
781 * @data: (array length=size) (element-type guint8) (transfer full): data to wrap
782 * @size: allocated size of @data
784 * Creates a new buffer that wraps the given @data. The memory will be freed
785 * with g_free and will be marked writable.
789 * Returns: (transfer full): a new #GstBuffer
792 gst_buffer_new_wrapped (gpointer data, gsize size)
794 return gst_buffer_new_wrapped_full (0, data, size, 0, size, data, g_free);
798 * gst_buffer_n_memory:
799 * @buffer: a #GstBuffer.
801 * Get the amount of memory blocks that this buffer has. This amount is never
802 * larger than what gst_buffer_get_max_memory() returns.
804 * Returns: (transfer full): the amount of memory block in this buffer.
807 gst_buffer_n_memory (GstBuffer * buffer)
809 g_return_val_if_fail (GST_IS_BUFFER (buffer), 0);
811 return GST_BUFFER_MEM_LEN (buffer);
815 * gst_buffer_prepend_memory:
816 * @buffer: a #GstBuffer.
817 * @mem: (transfer full): a #GstMemory.
819 * Prepend the memory block @mem to @buffer. This function takes
820 * ownership of @mem and thus doesn't increase its refcount.
822 * This function is identical to gst_buffer_insert_memory() with an index of 0.
823 * See gst_buffer_insert_memory() for more details.
826 gst_buffer_prepend_memory (GstBuffer * buffer, GstMemory * mem)
828 gst_buffer_insert_memory (buffer, 0, mem);
832 * gst_buffer_append_memory:
833 * @buffer: a #GstBuffer.
834 * @mem: (transfer full): a #GstMemory.
836 * Append the memory block @mem to @buffer. This function takes
837 * ownership of @mem and thus doesn't increase its refcount.
839 * This function is identical to gst_buffer_insert_memory() with an index of -1.
840 * See gst_buffer_insert_memory() for more details.
843 gst_buffer_append_memory (GstBuffer * buffer, GstMemory * mem)
845 gst_buffer_insert_memory (buffer, -1, mem);
849 * gst_buffer_insert_memory:
850 * @buffer: a #GstBuffer.
851 * @idx: the index to add the memory at, or -1 to append it to the end
852 * @mem: (transfer full): a #GstMemory.
854 * Insert the memory block @mem to @buffer at @idx. This function takes ownership
855 * of @mem and thus doesn't increase its refcount.
857 * Only gst_buffer_get_max_memory() can be added to a buffer. If more memory is
858 * added, existing memory blocks will automatically be merged to make room for
862 gst_buffer_insert_memory (GstBuffer * buffer, gint idx, GstMemory * mem)
864 g_return_if_fail (GST_IS_BUFFER (buffer));
865 g_return_if_fail (gst_buffer_is_writable (buffer));
866 g_return_if_fail (mem != NULL);
867 g_return_if_fail (idx == -1 ||
868 (idx >= 0 && idx <= GST_BUFFER_MEM_LEN (buffer)));
870 _memory_add (buffer, idx, mem, TRUE);
874 _get_mapped (GstBuffer * buffer, guint idx, GstMapInfo * info,
877 GstMemory *mem, *mapped;
879 mem = gst_memory_ref (GST_BUFFER_MEM_PTR (buffer, idx));
881 mapped = gst_memory_make_mapped (mem, info, flags);
884 /* memory changed, lock new memory */
885 gst_memory_lock (mapped, GST_LOCK_FLAG_EXCLUSIVE);
886 GST_BUFFER_MEM_PTR (buffer, idx) = mapped;
887 /* unlock old memory */
888 gst_memory_unlock (mem, GST_LOCK_FLAG_EXCLUSIVE);
889 GST_BUFFER_FLAG_SET (buffer, GST_BUFFER_FLAG_TAG_MEMORY);
891 gst_memory_unref (mem);
897 * gst_buffer_peek_memory:
898 * @buffer: a #GstBuffer.
901 * Get the memory block at @idx in @buffer. The memory block stays valid until
902 * the memory block in @buffer is removed, replaced or merged, typically with
903 * any call that modifies the memory in @buffer.
905 * Returns: (transfer none): the #GstMemory at @idx.
908 gst_buffer_peek_memory (GstBuffer * buffer, guint idx)
912 g_return_val_if_fail (GST_IS_BUFFER (buffer), NULL);
913 len = GST_BUFFER_MEM_LEN (buffer);
914 g_return_val_if_fail (idx < len, NULL);
916 return GST_BUFFER_MEM_PTR (buffer, idx);
920 * gst_buffer_get_memory:
921 * @buffer: a #GstBuffer.
924 * Get the memory block at index @idx in @buffer.
926 * Returns: (transfer full): a #GstMemory that contains the data of the
927 * memory block at @idx. Use gst_memory_unref () after usage.
930 gst_buffer_get_memory (GstBuffer * buffer, guint idx)
932 return gst_buffer_get_memory_range (buffer, idx, 1);
936 * gst_buffer_get_all_memory:
937 * @buffer: a #GstBuffer.
939 * Get all the memory block in @buffer. The memory blocks will be merged
940 * into one large #GstMemory.
942 * Returns: (transfer full): a #GstMemory that contains the merged memory.
943 * Use gst_memory_unref () after usage.
946 gst_buffer_get_all_memory (GstBuffer * buffer)
948 return gst_buffer_get_memory_range (buffer, 0, -1);
952 * gst_buffer_get_memory_range:
953 * @buffer: a #GstBuffer.
957 * Get @length memory blocks in @buffer starting at @idx. The memory blocks will
958 * be merged into one large #GstMemory.
960 * If @length is -1, all memory starting from @idx is merged.
962 * Returns: (transfer full): a #GstMemory that contains the merged data of @length
963 * blocks starting at @idx. Use gst_memory_unref () after usage.
966 gst_buffer_get_memory_range (GstBuffer * buffer, guint idx, gint length)
970 GST_CAT_DEBUG (GST_CAT_BUFFER, "idx %u, length %d", idx, length);
972 g_return_val_if_fail (GST_IS_BUFFER (buffer), NULL);
973 len = GST_BUFFER_MEM_LEN (buffer);
974 g_return_val_if_fail ((len == 0 && idx == 0 && length == -1) ||
975 (length == -1 && idx < len) || (length > 0 && length + idx <= len), NULL);
980 return _get_merged_memory (buffer, idx, length);
984 * gst_buffer_replace_memory:
985 * @buffer: a #GstBuffer.
987 * @mem: (transfer full): a #GstMemory
989 * Replaces the memory block at index @idx in @buffer with @mem.
992 gst_buffer_replace_memory (GstBuffer * buffer, guint idx, GstMemory * mem)
994 gst_buffer_replace_memory_range (buffer, idx, 1, mem);
998 * gst_buffer_replace_all_memory:
999 * @buffer: a #GstBuffer.
1000 * @mem: (transfer full): a #GstMemory
1002 * Replaces all memory in @buffer with @mem.
1005 gst_buffer_replace_all_memory (GstBuffer * buffer, GstMemory * mem)
1007 gst_buffer_replace_memory_range (buffer, 0, -1, mem);
1011 * gst_buffer_replace_memory_range:
1012 * @buffer: a #GstBuffer.
1014 * @length: a length should not be 0
1015 * @mem: (transfer full): a #GstMemory
1017 * Replaces @length memory blocks in @buffer starting at @idx with @mem.
1019 * If @length is -1, all memory starting from @idx will be removed and
1020 * replaced with @mem.
1022 * @buffer should be writable.
1025 gst_buffer_replace_memory_range (GstBuffer * buffer, guint idx, gint length,
1030 g_return_if_fail (GST_IS_BUFFER (buffer));
1031 g_return_if_fail (gst_buffer_is_writable (buffer));
1033 GST_CAT_DEBUG (GST_CAT_BUFFER, "idx %u, length %d, %p", idx, length, mem);
1035 len = GST_BUFFER_MEM_LEN (buffer);
1036 g_return_if_fail ((len == 0 && idx == 0 && length == -1) ||
1037 (length == -1 && idx < len) || (length > 0 && length + idx <= len));
1042 _replace_memory (buffer, len, idx, length, mem);
1046 * gst_buffer_remove_memory:
1047 * @buffer: a #GstBuffer.
1050 * Remove the memory block in @b at index @i.
1053 gst_buffer_remove_memory (GstBuffer * buffer, guint idx)
1055 gst_buffer_remove_memory_range (buffer, idx, 1);
1059 * gst_buffer_remove_all_memory:
1060 * @buffer: a #GstBuffer.
1062 * Remove all the memory blocks in @buffer.
1065 gst_buffer_remove_all_memory (GstBuffer * buffer)
1067 gst_buffer_remove_memory_range (buffer, 0, -1);
1071 * gst_buffer_remove_memory_range:
1072 * @buffer: a #GstBuffer.
1076 * Remove @length memory blocks in @buffer starting from @idx.
1078 * @length can be -1, in which case all memory starting from @idx is removed.
1081 gst_buffer_remove_memory_range (GstBuffer * buffer, guint idx, gint length)
1085 g_return_if_fail (GST_IS_BUFFER (buffer));
1086 g_return_if_fail (gst_buffer_is_writable (buffer));
1088 GST_CAT_DEBUG (GST_CAT_BUFFER, "idx %u, length %d", idx, length);
1090 len = GST_BUFFER_MEM_LEN (buffer);
1091 g_return_if_fail ((len == 0 && idx == 0 && length == -1) ||
1092 (length == -1 && idx < len) || length + idx <= len);
1097 _replace_memory (buffer, len, idx, length, NULL);
1101 * gst_buffer_find_memory:
1102 * @buffer: a #GstBuffer.
1103 * @offset: an offset
1105 * @idx: (out): pointer to index
1106 * @length: (out): pointer to length
1107 * @skip: (out): pointer to skip
1109 * Find the memory blocks that span @size bytes starting from @offset
1112 * When this function returns %TRUE, @idx will contain the index of the first
1113 * memory bock where the byte for @offset can be found and @length contains the
1114 * number of memory blocks containing the @size remaining bytes. @skip contains
1115 * the number of bytes to skip in the memory bock at @idx to get to the byte
1118 * @size can be -1 to get all the memory blocks after @idx.
1120 * Returns: %TRUE when @size bytes starting from @offset could be found in
1121 * @buffer and @idx, @length and @skip will be filled.
1124 gst_buffer_find_memory (GstBuffer * buffer, gsize offset, gsize size,
1125 guint * idx, guint * length, gsize * skip)
1127 guint i, len, found;
1129 g_return_val_if_fail (GST_IS_BUFFER (buffer), FALSE);
1130 g_return_val_if_fail (idx != NULL, FALSE);
1131 g_return_val_if_fail (length != NULL, FALSE);
1132 g_return_val_if_fail (skip != NULL, FALSE);
1134 len = GST_BUFFER_MEM_LEN (buffer);
1137 for (i = 0; i < len; i++) {
1141 mem = GST_BUFFER_MEM_PTR (buffer, i);
1142 s = gst_memory_get_sizes (mem, NULL, NULL);
1145 /* block before offset, or empty block, skip */
1148 /* block after offset */
1150 /* first block, remember index and offset */
1154 /* return remaining blocks */
1161 /* count the amount of found bytes */
1163 if (found >= size) {
1164 /* we have enough bytes */
1165 *length = i - *idx + 1;
1174 * gst_buffer_is_memory_range_writable:
1175 * @buffer: a #GstBuffer.
1177 * @length: a length should not be 0
1179 * Check if @length memory blocks in @buffer starting from @idx are writable.
1181 * @length can be -1 to check all the memory blocks after @idx.
1183 * Note that this function does not check if @buffer is writable, use
1184 * gst_buffer_is_writable() to check that if needed.
1186 * Returns: %TRUE if the memory range is writable
1191 gst_buffer_is_memory_range_writable (GstBuffer * buffer, guint idx, gint length)
1195 g_return_val_if_fail (GST_IS_BUFFER (buffer), FALSE);
1197 GST_CAT_DEBUG (GST_CAT_BUFFER, "idx %u, length %d", idx, length);
1199 len = GST_BUFFER_MEM_LEN (buffer);
1200 g_return_val_if_fail ((len == 0 && idx == 0 && length == -1) ||
1201 (length == -1 && idx < len) || (length > 0 && length + idx <= len),
1209 for (i = 0; i < len; i++) {
1210 if (!gst_memory_is_writable (GST_BUFFER_MEM_PTR (buffer, i + idx)))
1217 * gst_buffer_is_all_memory_writable:
1218 * @buffer: a #GstBuffer.
1220 * Check if all memory blocks in @buffer are writable.
1222 * Note that this function does not check if @buffer is writable, use
1223 * gst_buffer_is_writable() to check that if needed.
1225 * Returns: %TRUE if all memory blocks in @buffer are writable
1230 gst_buffer_is_all_memory_writable (GstBuffer * buffer)
1232 return gst_buffer_is_memory_range_writable (buffer, 0, -1);
1236 * gst_buffer_get_sizes:
1237 * @buffer: a #GstBuffer.
1238 * @offset: (out): a pointer to the offset
1239 * @maxsize: (out): a pointer to the maxsize
1241 * Get the total size of the memory blocks in @b.
1243 * When not %NULL, @offset will contain the offset of the data in the
1244 * first memory block in @buffer and @maxsize will contain the sum of
1245 * the size and @offset and the amount of extra padding on the last
1246 * memory block. @offset and @maxsize can be used to resize the
1247 * buffer memory blocks with gst_buffer_resize().
1249 * Returns: total size of the memory blocks in @buffer.
1252 gst_buffer_get_sizes (GstBuffer * buffer, gsize * offset, gsize * maxsize)
1254 return gst_buffer_get_sizes_range (buffer, 0, -1, offset, maxsize);
1258 * gst_buffer_get_size:
1259 * @buffer: a #GstBuffer.
1261 * Get the total size of the memory blocks in @buffer.
1263 * Returns: total size of the memory blocks in @buffer.
1266 gst_buffer_get_size (GstBuffer * buffer)
1268 return gst_buffer_get_sizes_range (buffer, 0, -1, NULL, NULL);
1272 * gst_buffer_get_sizes_range:
1273 * @buffer: a #GstBuffer.
1276 * @offset: (out): a pointer to the offset
1277 * @maxsize: (out): a pointer to the maxsize
1279 * Get the total size of @length memory blocks stating from @idx in @buffer.
1281 * When not %NULL, @offset will contain the offset of the data in the
1282 * memory block in @buffer at @idx and @maxsize will contain the sum of the size
1283 * and @offset and the amount of extra padding on the memory block at @idx +
1285 * @offset and @maxsize can be used to resize the buffer memory blocks with
1286 * gst_buffer_resize_range().
1288 * Returns: total size of @length memory blocks starting at @idx in @buffer.
1291 gst_buffer_get_sizes_range (GstBuffer * buffer, guint idx, gint length,
1292 gsize * offset, gsize * maxsize)
1298 g_return_val_if_fail (GST_IS_BUFFER (buffer), 0);
1299 len = GST_BUFFER_MEM_LEN (buffer);
1300 g_return_val_if_fail ((len == 0 && idx == 0 && length == -1) ||
1301 (length == -1 && idx < len) || (length + idx <= len), 0);
1306 if (G_LIKELY (length == 1)) {
1308 mem = GST_BUFFER_MEM_PTR (buffer, idx);
1309 size = gst_memory_get_sizes (mem, offset, maxsize);
1315 size = offs = extra = 0;
1316 for (i = idx; i < end; i++) {
1319 mem = GST_BUFFER_MEM_PTR (buffer, i);
1320 s = gst_memory_get_sizes (mem, &o, &ms);
1324 /* first size, take accumulated data before as the offset */
1328 /* save the amount of data after this block */
1329 extra = ms - (o + s);
1331 /* empty block, add as extra */
1338 *maxsize = offs + size + extra;
1344 * gst_buffer_resize:
1345 * @buffer: a #GstBuffer.
1346 * @offset: the offset adjustment
1347 * @size: the new size or -1 to just adjust the offset
1349 * Set the offset and total size of the memory blocks in @buffer.
1352 gst_buffer_resize (GstBuffer * buffer, gssize offset, gssize size)
1354 gst_buffer_resize_range (buffer, 0, -1, offset, size);
1358 * gst_buffer_set_size:
1359 * @buffer: a #GstBuffer.
1360 * @size: the new size
1362 * Set the total size of the memory blocks in @buffer.
1365 gst_buffer_set_size (GstBuffer * buffer, gssize size)
1367 gst_buffer_resize_range (buffer, 0, -1, 0, size);
1371 * gst_buffer_resize_range:
1372 * @buffer: a #GstBuffer.
1375 * @offset: the offset adjustment
1376 * @size: the new size or -1 to just adjust the offset
1378 * Set the total size of the @length memory blocks starting at @idx in
1381 * Returns: %TRUE if resizing succeeded, %FALSE otherwise.
1384 gst_buffer_resize_range (GstBuffer * buffer, guint idx, gint length,
1385 gssize offset, gssize size)
1388 gsize bsize, bufsize, bufoffs, bufmax;
1390 g_return_val_if_fail (gst_buffer_is_writable (buffer), FALSE);
1391 g_return_val_if_fail (size >= -1, FALSE);
1393 len = GST_BUFFER_MEM_LEN (buffer);
1394 g_return_val_if_fail ((len == 0 && idx == 0 && length == -1) ||
1395 (length == -1 && idx < len) || (length + idx <= len), FALSE);
1400 bufsize = gst_buffer_get_sizes_range (buffer, idx, length, &bufoffs, &bufmax);
1402 GST_CAT_LOG (GST_CAT_BUFFER, "trim %p %" G_GSSIZE_FORMAT "-%" G_GSSIZE_FORMAT
1403 " size:%" G_GSIZE_FORMAT " offs:%" G_GSIZE_FORMAT " max:%"
1404 G_GSIZE_FORMAT, buffer, offset, size, bufsize, bufoffs, bufmax);
1406 /* we can't go back further than the current offset or past the end of the
1408 g_return_val_if_fail ((offset < 0 && bufoffs >= -offset) || (offset >= 0
1409 && bufoffs + offset <= bufmax), FALSE);
1411 g_return_val_if_fail (bufsize >= offset, FALSE);
1412 size = bufsize - offset;
1414 g_return_val_if_fail (bufmax >= bufoffs + offset + size, FALSE);
1417 if (offset == 0 && size == bufsize)
1422 for (i = idx; i < end; i++) {
1426 mem = GST_BUFFER_MEM_PTR (buffer, i);
1427 bsize = gst_memory_get_sizes (mem, NULL, NULL);
1430 /* last buffer always gets resized to the remaining size */
1433 /* shrink buffers before the offset */
1434 else if ((gssize) bsize <= offset) {
1436 noffs = offset - bsize;
1439 /* clip other buffers */
1441 left = MIN (bsize - offset, size);
1443 if (offset != 0 || left != bsize) {
1444 if (gst_memory_is_writable (mem)) {
1445 gst_memory_resize (mem, offset, left);
1447 GstMemory *newmem = NULL;
1449 if (!GST_MEMORY_IS_NO_SHARE (mem))
1450 newmem = gst_memory_share (mem, offset, left);
1453 newmem = gst_memory_copy (mem, offset, left);
1458 gst_memory_lock (newmem, GST_LOCK_FLAG_EXCLUSIVE);
1459 GST_BUFFER_MEM_PTR (buffer, i) = newmem;
1460 gst_memory_unlock (mem, GST_LOCK_FLAG_EXCLUSIVE);
1461 gst_memory_unref (mem);
1463 GST_BUFFER_FLAG_SET (buffer, GST_BUFFER_FLAG_TAG_MEMORY);
1476 * @buffer: a #GstBuffer.
1477 * @info: (out): info about the mapping
1478 * @flags: flags for the mapping
1480 * This function fills @info with the #GstMapInfo of all merged memory
1481 * blocks in @buffer.
1483 * @flags describe the desired access of the memory. When @flags is
1484 * #GST_MAP_WRITE, @buffer should be writable (as returned from
1485 * gst_buffer_is_writable()).
1487 * When @buffer is writable but the memory isn't, a writable copy will
1488 * automatically be created and returned. The readonly copy of the
1489 * buffer memory will then also be replaced with this writable copy.
1491 * The memory in @info should be unmapped with gst_buffer_unmap() after
1494 * Returns: %TRUE if the map succeeded and @info contains valid data.
1497 gst_buffer_map (GstBuffer * buffer, GstMapInfo * info, GstMapFlags flags)
1499 return gst_buffer_map_range (buffer, 0, -1, info, flags);
1503 * gst_buffer_map_range:
1504 * @buffer: a #GstBuffer.
1507 * @info: (out): info about the mapping
1508 * @flags: flags for the mapping
1510 * This function fills @info with the #GstMapInfo of @length merged memory blocks
1511 * starting at @idx in @buffer. When @length is -1, all memory blocks starting
1512 * from @idx are merged and mapped.
1514 * @flags describe the desired access of the memory. When @flags is
1515 * #GST_MAP_WRITE, @buffer should be writable (as returned from
1516 * gst_buffer_is_writable()).
1518 * When @buffer is writable but the memory isn't, a writable copy will
1519 * automatically be created and returned. The readonly copy of the buffer memory
1520 * will then also be replaced with this writable copy.
1522 * The memory in @info should be unmapped with gst_buffer_unmap() after usage.
1524 * Returns: %TRUE if the map succeeded and @info contains valid
1528 gst_buffer_map_range (GstBuffer * buffer, guint idx, gint length,
1529 GstMapInfo * info, GstMapFlags flags)
1531 GstMemory *mem, *nmem;
1532 gboolean write, writable;
1535 g_return_val_if_fail (GST_IS_BUFFER (buffer), FALSE);
1536 g_return_val_if_fail (info != NULL, FALSE);
1537 len = GST_BUFFER_MEM_LEN (buffer);
1538 g_return_val_if_fail ((len == 0 && idx == 0 && length == -1) ||
1539 (length == -1 && idx < len) || (length > 0
1540 && length + idx <= len), FALSE);
1542 GST_CAT_LOG (GST_CAT_BUFFER, "buffer %p, idx %u, length %d, flags %04x",
1543 buffer, idx, length, flags);
1545 write = (flags & GST_MAP_WRITE) != 0;
1546 writable = gst_buffer_is_writable (buffer);
1548 /* check if we can write when asked for write access */
1549 if (G_UNLIKELY (write && !writable))
1555 mem = _get_merged_memory (buffer, idx, length);
1556 if (G_UNLIKELY (mem == NULL))
1559 /* now try to map */
1560 nmem = gst_memory_make_mapped (mem, info, flags);
1561 if (G_UNLIKELY (nmem == NULL))
1564 /* if we merged or when the map returned a different memory, we try to replace
1565 * the memory in the buffer */
1566 if (G_UNLIKELY (length > 1 || nmem != mem)) {
1567 /* if the buffer is writable, replace the memory */
1569 _replace_memory (buffer, len, idx, length, gst_memory_ref (nmem));
1572 GST_CAT_DEBUG (GST_CAT_PERFORMANCE,
1573 "temporary mapping for memory %p in buffer %p", nmem, buffer);
1582 GST_WARNING_OBJECT (buffer, "write map requested on non-writable buffer");
1583 g_critical ("write map requested on non-writable buffer");
1584 memset (info, 0, sizeof (GstMapInfo));
1589 /* empty buffer, we need to return NULL */
1590 GST_DEBUG_OBJECT (buffer, "can't get buffer memory");
1591 memset (info, 0, sizeof (GstMapInfo));
1596 GST_DEBUG_OBJECT (buffer, "cannot map memory");
1597 memset (info, 0, sizeof (GstMapInfo));
1604 * @buffer: a #GstBuffer.
1605 * @info: a #GstMapInfo
1607 * Release the memory previously mapped with gst_buffer_map().
1610 gst_buffer_unmap (GstBuffer * buffer, GstMapInfo * info)
1612 g_return_if_fail (GST_IS_BUFFER (buffer));
1613 g_return_if_fail (info != NULL);
1615 /* we need to check for NULL, it is possible that we tried to map a buffer
1616 * without memory and we should be able to unmap that fine */
1617 if (G_LIKELY (info->memory)) {
1618 gst_memory_unmap (info->memory, info);
1619 gst_memory_unref (info->memory);
1625 * @buffer: a #GstBuffer.
1626 * @offset: the offset to fill
1627 * @src: (array length=size) (element-type guint8): the source address
1628 * @size: the size to fill
1630 * Copy @size bytes from @src to @buffer at @offset.
1632 * Returns: The amount of bytes copied. This value can be lower than @size
1633 * when @buffer did not contain enough data.
1636 gst_buffer_fill (GstBuffer * buffer, gsize offset, gconstpointer src,
1640 const guint8 *ptr = src;
1642 g_return_val_if_fail (GST_IS_BUFFER (buffer), 0);
1643 g_return_val_if_fail (gst_buffer_is_writable (buffer), 0);
1644 g_return_val_if_fail (src != NULL || size == 0, 0);
1646 GST_CAT_LOG (GST_CAT_BUFFER,
1647 "buffer %p, offset %" G_GSIZE_FORMAT ", size %" G_GSIZE_FORMAT, buffer,
1650 len = GST_BUFFER_MEM_LEN (buffer);
1653 for (i = 0; i < len && left > 0; i++) {
1658 mem = _get_mapped (buffer, i, &info, GST_MAP_WRITE);
1659 if (info.size > offset) {
1660 /* we have enough */
1661 tocopy = MIN (info.size - offset, left);
1662 memcpy ((guint8 *) info.data + offset, ptr, tocopy);
1667 /* offset past buffer, skip */
1668 offset -= info.size;
1670 gst_memory_unmap (mem, &info);
1676 * gst_buffer_extract:
1677 * @buffer: a #GstBuffer.
1678 * @offset: the offset to extract
1679 * @dest: the destination address
1680 * @size: the size to extract
1682 * Copy @size bytes starting from @offset in @buffer to @dest.
1684 * Returns: The amount of bytes extracted. This value can be lower than @size
1685 * when @buffer did not contain enough data.
1688 gst_buffer_extract (GstBuffer * buffer, gsize offset, gpointer dest, gsize size)
1693 g_return_val_if_fail (GST_IS_BUFFER (buffer), 0);
1694 g_return_val_if_fail (dest != NULL, 0);
1696 GST_CAT_LOG (GST_CAT_BUFFER,
1697 "buffer %p, offset %" G_GSIZE_FORMAT ", size %" G_GSIZE_FORMAT, buffer,
1700 len = GST_BUFFER_MEM_LEN (buffer);
1703 for (i = 0; i < len && left > 0; i++) {
1708 mem = _get_mapped (buffer, i, &info, GST_MAP_READ);
1709 if (info.size > offset) {
1710 /* we have enough */
1711 tocopy = MIN (info.size - offset, left);
1712 memcpy (ptr, (guint8 *) info.data + offset, tocopy);
1717 /* offset past buffer, skip */
1718 offset -= info.size;
1720 gst_memory_unmap (mem, &info);
1726 * gst_buffer_memcmp:
1727 * @buffer: a #GstBuffer.
1728 * @offset: the offset in @buffer
1729 * @mem: (array length=size) (element-type guint8): the memory to compare
1730 * @size: the size to compare
1732 * Compare @size bytes starting from @offset in @buffer with the memory in @mem.
1734 * Returns: 0 if the memory is equal.
1737 gst_buffer_memcmp (GstBuffer * buffer, gsize offset, gconstpointer mem,
1741 const guint8 *ptr = mem;
1744 g_return_val_if_fail (GST_IS_BUFFER (buffer), 0);
1745 g_return_val_if_fail (mem != NULL, 0);
1747 GST_CAT_LOG (GST_CAT_BUFFER,
1748 "buffer %p, offset %" G_GSIZE_FORMAT ", size %" G_GSIZE_FORMAT, buffer,
1751 if (G_UNLIKELY (gst_buffer_get_size (buffer) < offset + size))
1754 len = GST_BUFFER_MEM_LEN (buffer);
1756 for (i = 0; i < len && size > 0 && res == 0; i++) {
1761 mem = _get_mapped (buffer, i, &info, GST_MAP_READ);
1762 if (info.size > offset) {
1763 /* we have enough */
1764 tocmp = MIN (info.size - offset, size);
1765 res = memcmp (ptr, (guint8 *) info.data + offset, tocmp);
1770 /* offset past buffer, skip */
1771 offset -= info.size;
1773 gst_memory_unmap (mem, &info);
1779 * gst_buffer_memset:
1780 * @buffer: a #GstBuffer.
1781 * @offset: the offset in @buffer
1782 * @val: the value to set
1783 * @size: the size to set
1785 * Fill @buf with @size bytes with @val starting from @offset.
1787 * Returns: The amount of bytes filled. This value can be lower than @size
1788 * when @buffer did not contain enough data.
1791 gst_buffer_memset (GstBuffer * buffer, gsize offset, guint8 val, gsize size)
1795 g_return_val_if_fail (GST_IS_BUFFER (buffer), 0);
1796 g_return_val_if_fail (gst_buffer_is_writable (buffer), 0);
1798 GST_CAT_LOG (GST_CAT_BUFFER,
1799 "buffer %p, offset %" G_GSIZE_FORMAT ", val %02x, size %" G_GSIZE_FORMAT,
1800 buffer, offset, val, size);
1802 len = GST_BUFFER_MEM_LEN (buffer);
1805 for (i = 0; i < len && left > 0; i++) {
1810 mem = _get_mapped (buffer, i, &info, GST_MAP_WRITE);
1811 if (info.size > offset) {
1812 /* we have enough */
1813 toset = MIN (info.size - offset, left);
1814 memset ((guint8 *) info.data + offset, val, toset);
1818 /* offset past buffer, skip */
1819 offset -= info.size;
1821 gst_memory_unmap (mem, &info);
1827 * gst_buffer_copy_region:
1828 * @parent: a #GstBuffer.
1829 * @flags: the #GstBufferCopyFlags
1830 * @offset: the offset into parent #GstBuffer at which the new sub-buffer
1832 * @size: the size of the new #GstBuffer sub-buffer, in bytes.
1834 * Creates a sub-buffer from @parent at @offset and @size.
1835 * This sub-buffer uses the actual memory space of the parent buffer.
1836 * This function will copy the offset and timestamp fields when the
1837 * offset is 0. If not, they will be set to #GST_CLOCK_TIME_NONE and
1838 * #GST_BUFFER_OFFSET_NONE.
1839 * If @offset equals 0 and @size equals the total size of @buffer, the
1840 * duration and offset end fields are also copied. If not they will be set
1841 * to #GST_CLOCK_TIME_NONE and #GST_BUFFER_OFFSET_NONE.
1845 * Returns: (transfer full): the new #GstBuffer or NULL if the arguments were
1849 gst_buffer_copy_region (GstBuffer * buffer, GstBufferCopyFlags flags,
1850 gsize offset, gsize size)
1854 g_return_val_if_fail (buffer != NULL, NULL);
1856 /* create the new buffer */
1857 copy = gst_buffer_new ();
1859 GST_CAT_LOG (GST_CAT_BUFFER, "new region copy %p of %p %" G_GSIZE_FORMAT
1860 "-%" G_GSIZE_FORMAT, copy, buffer, offset, size);
1862 if (!gst_buffer_copy_into (copy, buffer, flags, offset, size))
1863 gst_buffer_replace (©, NULL);
1869 * gst_buffer_append:
1870 * @buf1: (transfer full): the first source #GstBuffer to append.
1871 * @buf2: (transfer full): the second source #GstBuffer to append.
1873 * Append all the memory from @buf2 to @buf1. The result buffer will contain a
1874 * concatenation of the memory of @buf1 and @buf2.
1876 * Returns: (transfer full): the new #GstBuffer that contains the memory
1877 * of the two source buffers.
1880 gst_buffer_append (GstBuffer * buf1, GstBuffer * buf2)
1882 return gst_buffer_append_region (buf1, buf2, 0, -1);
1886 * gst_buffer_append_region:
1887 * @buf1: (transfer full): the first source #GstBuffer to append.
1888 * @buf2: (transfer full): the second source #GstBuffer to append.
1889 * @offset: the offset in @buf2
1890 * @size: the size or -1 of @buf2
1892 * Append @size bytes at @offset from @buf2 to @buf1. The result buffer will
1893 * contain a concatenation of the memory of @buf1 and the requested region of
1896 * Returns: (transfer full): the new #GstBuffer that contains the memory
1897 * of the two source buffers.
1900 gst_buffer_append_region (GstBuffer * buf1, GstBuffer * buf2, gssize offset,
1905 g_return_val_if_fail (GST_IS_BUFFER (buf1), NULL);
1906 g_return_val_if_fail (GST_IS_BUFFER (buf2), NULL);
1908 buf1 = gst_buffer_make_writable (buf1);
1909 buf2 = gst_buffer_make_writable (buf2);
1911 gst_buffer_resize (buf2, offset, size);
1913 len = GST_BUFFER_MEM_LEN (buf2);
1914 for (i = 0; i < len; i++) {
1917 mem = GST_BUFFER_MEM_PTR (buf2, i);
1918 GST_BUFFER_MEM_PTR (buf2, i) = NULL;
1919 _memory_add (buf1, -1, mem, FALSE);
1922 GST_BUFFER_MEM_LEN (buf2) = 0;
1923 GST_BUFFER_FLAG_SET (buf2, GST_BUFFER_FLAG_TAG_MEMORY);
1924 gst_buffer_unref (buf2);
1930 * gst_buffer_get_meta:
1931 * @buffer: a #GstBuffer
1932 * @api: the #GType of an API
1934 * Get the metadata for @api on buffer. When there is no such
1935 * metadata, NULL is returned.
1937 * Returns: (transfer none): the metadata for @api on @buffer.
1940 gst_buffer_get_meta (GstBuffer * buffer, GType api)
1943 GstMeta *result = NULL;
1945 g_return_val_if_fail (buffer != NULL, NULL);
1946 g_return_val_if_fail (api != 0, NULL);
1948 /* find GstMeta of the requested API */
1949 for (item = GST_BUFFER_META (buffer); item; item = item->next) {
1950 GstMeta *meta = &item->meta;
1951 if (meta->info->api == api) {
1960 * gst_buffer_add_meta:
1961 * @buffer: a #GstBuffer
1962 * @info: a #GstMetaInfo
1963 * @params: params for @info
1965 * Add metadata for @info to @buffer using the parameters in @params.
1967 * Returns: (transfer none): the metadata for the api in @info on @buffer.
1970 gst_buffer_add_meta (GstBuffer * buffer, const GstMetaInfo * info,
1974 GstMeta *result = NULL;
1977 g_return_val_if_fail (buffer != NULL, NULL);
1978 g_return_val_if_fail (info != NULL, NULL);
1979 g_return_val_if_fail (gst_buffer_is_writable (buffer), NULL);
1981 /* create a new slice */
1982 size = ITEM_SIZE (info);
1983 item = g_slice_alloc (size);
1984 result = &item->meta;
1985 result->info = info;
1986 result->flags = GST_META_FLAG_NONE;
1988 GST_CAT_DEBUG (GST_CAT_BUFFER,
1989 "alloc metadata %p (%s) of size %" G_GSIZE_FORMAT, result,
1990 g_type_name (info->type), info->size);
1992 /* call the init_func when needed */
1993 if (info->init_func)
1994 if (!info->init_func (result, params, buffer))
1997 /* and add to the list of metadata */
1998 item->next = GST_BUFFER_META (buffer);
1999 GST_BUFFER_META (buffer) = item;
2005 g_slice_free1 (size, item);
2011 * gst_buffer_remove_meta:
2012 * @buffer: a #GstBuffer
2015 * Remove the metadata for @meta on @buffer.
2017 * Returns: %TRUE if the metadata existed and was removed, %FALSE if no such
2018 * metadata was on @buffer.
2021 gst_buffer_remove_meta (GstBuffer * buffer, GstMeta * meta)
2023 GstMetaItem *walk, *prev;
2025 g_return_val_if_fail (buffer != NULL, FALSE);
2026 g_return_val_if_fail (meta != NULL, FALSE);
2027 g_return_val_if_fail (gst_buffer_is_writable (buffer), FALSE);
2028 g_return_val_if_fail (!GST_META_FLAG_IS_SET (meta, GST_META_FLAG_LOCKED),
2031 /* find the metadata and delete */
2032 prev = GST_BUFFER_META (buffer);
2033 for (walk = prev; walk; walk = walk->next) {
2034 GstMeta *m = &walk->meta;
2036 const GstMetaInfo *info = meta->info;
2038 /* remove from list */
2039 if (GST_BUFFER_META (buffer) == walk)
2040 GST_BUFFER_META (buffer) = walk->next;
2042 prev->next = walk->next;
2043 /* call free_func if any */
2044 if (info->free_func)
2045 info->free_func (m, buffer);
2047 /* and free the slice */
2048 g_slice_free1 (ITEM_SIZE (info), walk);
2053 return walk != NULL;
2057 * gst_buffer_iterate_meta:
2058 * @buffer: a #GstBuffer
2059 * @state: an opaque state pointer
2061 * Retrieve the next #GstMeta after @current. If @state points
2062 * to %NULL, the first metadata is returned.
2064 * @state will be updated with an opaque state pointer
2066 * Returns: (transfer none): The next #GstMeta or %NULL when there are
2070 gst_buffer_iterate_meta (GstBuffer * buffer, gpointer * state)
2074 g_return_val_if_fail (buffer != NULL, NULL);
2075 g_return_val_if_fail (state != NULL, NULL);
2077 meta = (GstMetaItem **) state;
2079 /* state NULL, move to first item */
2080 *meta = GST_BUFFER_META (buffer);
2082 /* state !NULL, move to next item in list */
2083 *meta = (*meta)->next;
2086 return &(*meta)->meta;
2092 * gst_buffer_foreach_meta:
2093 * @buffer: a #GstBuffer
2094 * @func: (scope call): a #GstBufferForeachMetaFunc to call
2095 * @user_data: (closure): user data passed to @func
2097 * Call @func with @user_data for each meta in @buffer.
2099 * @func can modify the passed meta pointer or its contents. The return value
2100 * of @func define if this function returns or if the remaining metadata items
2101 * in the buffer should be skipped.
2103 * Returns: %FALSE when @func returned %FALSE for one of the metadata.
2106 gst_buffer_foreach_meta (GstBuffer * buffer, GstBufferForeachMetaFunc func,
2109 GstMetaItem *walk, *prev, *next;
2110 gboolean res = TRUE;
2112 g_return_val_if_fail (buffer != NULL, FALSE);
2113 g_return_val_if_fail (func != NULL, FALSE);
2115 /* find the metadata and delete */
2116 prev = GST_BUFFER_META (buffer);
2117 for (walk = prev; walk; walk = next) {
2120 m = new = &walk->meta;
2123 res = func (buffer, &new, user_data);
2126 const GstMetaInfo *info = m->info;
2128 GST_CAT_DEBUG (GST_CAT_BUFFER, "remove metadata %p (%s)", m,
2129 g_type_name (info->type));
2131 g_return_val_if_fail (gst_buffer_is_writable (buffer), FALSE);
2132 g_return_val_if_fail (!GST_META_FLAG_IS_SET (m, GST_META_FLAG_LOCKED),
2135 /* remove from list */
2136 if (GST_BUFFER_META (buffer) == walk)
2137 GST_BUFFER_META (buffer) = next;
2141 /* call free_func if any */
2142 if (info->free_func)
2143 info->free_func (m, buffer);
2145 /* and free the slice */
2146 g_slice_free1 (ITEM_SIZE (info), walk);
2155 * gst_buffer_extract_dup:
2156 * @buffer: a #GstBuffer
2157 * @offset: the offset to extract
2158 * @size: the size to extract
2159 * @dest: (array length=dest_size) (element-type guint8) (out): A pointer where
2160 * the destination array will be written.
2161 * @dest_size: (out): A location where the size of @dest can be written
2163 * Extracts a copy of at most @size bytes the data at @offset into a #GBytes.
2164 * @dest must be freed using g_free() when done.
2170 gst_buffer_extract_dup (GstBuffer * buffer, gsize offset, gsize size,
2171 gpointer * dest, gsize * dest_size)
2175 real_size = gst_buffer_get_size (buffer);
2177 *dest = g_malloc (MIN (real_size - offset, size));
2179 *dest_size = gst_buffer_extract (buffer, offset, *dest, size);