2 * Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
3 * 2000 Wim Taymans <wtay@chello.be>
5 * gstbuffer.c: Buffer operations
7 * This library is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Library General Public
9 * License as published by the Free Software Foundation; either
10 * version 2 of the License, or (at your option) any later version.
12 * This library is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Library General Public License for more details.
17 * You should have received a copy of the GNU Library General Public
18 * License along with this library; if not, write to the
19 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
20 * Boston, MA 02111-1307, USA.
25 * @short_description: Data-passing buffer type, supporting sub-buffers.
26 * @see_also: #GstPad, #GstMiniObject, #GstBufferPool
28 * Buffers are the basic unit of data transfer in GStreamer. The #GstBuffer
29 * type provides all the state necessary to define the regions of memory as
30 * part of a stream. Region copies are also supported, allowing a smaller
31 * region of a buffer to become its own buffer, with mechanisms in place to
32 * ensure that neither memory space goes away prematurely.
34 * Buffers are usually created with gst_buffer_new(). After a buffer has been
35 * created one will typically allocate memory for it and add it to the buffer.
36 * The following example creates a buffer that can hold a given video frame
37 * with a given width, height and bits per plane.
39 * <title>Creating a buffer for a video frame</title>
43 * gint size, width, height, bpp;
45 * size = width * height * bpp;
46 * buffer = gst_buffer_new ();
47 * memory = gst_allocator_alloc (NULL, size, 0);
48 * gst_buffer_take_memory (buffer, -1, memory);
53 * Alternatively, use gst_buffer_new_allocate()
54 * to create a buffer with preallocated data of a given size.
56 * Buffers can contain a list of #GstMemory objects. You can retrieve how many
57 * memory objects with gst_buffer_n_memory() and you can get a pointer
58 * to memory with gst_buffer_peek_memory()
60 * A buffer will usually have timestamps, and a duration, but neither of these
61 * are guaranteed (they may be set to #GST_CLOCK_TIME_NONE). Whenever a
62 * meaningful value can be given for these, they should be set. The timestamps
63 * and duration are measured in nanoseconds (they are #GstClockTime values).
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 #GstCaps set on it). 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
78 * To efficiently create a smaller buffer out of an existing one, you can
79 * use gst_buffer_copy_region().
81 * If a plug-in wants to modify the buffer data or metadata in-place, it should
82 * first obtain a buffer that is safe to modify by using
83 * gst_buffer_make_writable(). This function is optimized so that a copy will
84 * only be made when it is necessary.
86 * Several flags of the buffer can be set and unset with the
87 * GST_BUFFER_FLAG_SET() and GST_BUFFER_FLAG_UNSET() macros. Use
88 * GST_BUFFER_FLAG_IS_SET() to test if a certain #GstBufferFlag is set.
90 * Buffers can be efficiently merged into a larger buffer with
91 * gst_buffer_span(), which avoids memory copies when the gst_buffer_is_span_fast()
92 * function returns TRUE.
94 * An element should either unref the buffer or push it out on a src pad
95 * using gst_pad_push() (see #GstPad).
97 * Buffers are usually freed by unreffing them with gst_buffer_unref(). When
98 * the refcount drops to 0, any data pointed to by the buffer is unreffed as
101 * Last reviewed on November 8, 2011 (0.11.2)
103 #include "gst_private.h"
112 #include "gstbuffer.h"
113 #include "gstbufferpool.h"
115 #include "gstutils.h"
116 #include "gstminiobject.h"
117 #include "gstversion.h"
119 GType _gst_buffer_type = 0;
121 static GstMemory *_gst_buffer_arr_span (GstMemory ** mem[], gsize len[],
122 guint n, gsize offset, gsize size, gboolean writable);
124 typedef struct _GstMetaItem GstMetaItem;
131 #define ITEM_SIZE(info) ((info)->size + sizeof (GstMetaItem))
133 #define GST_BUFFER_MEM_MAX 16
135 #define GST_BUFFER_MEM_LEN(b) (((GstBufferImpl *)(b))->len)
136 #define GST_BUFFER_MEM_ARRAY(b) (((GstBufferImpl *)(b))->mem)
137 #define GST_BUFFER_MEM_PTR(b,i) (((GstBufferImpl *)(b))->mem[i])
138 #define GST_BUFFER_BUFMEM(b) (((GstBufferImpl *)(b))->bufmem)
139 #define GST_BUFFER_META(b) (((GstBufferImpl *)(b))->item)
145 /* the memory blocks */
147 GstMemory *mem[GST_BUFFER_MEM_MAX];
149 /* memory of the buffer when allocated from 1 chunk */
152 /* FIXME, make metadata allocation more efficient by using part of the
158 _span_memory (GstBuffer * buffer, gsize offset, gsize size, gboolean writable)
160 GstMemory *span, **mem[1];
163 /* not enough room, span buffers */
164 mem[0] = GST_BUFFER_MEM_ARRAY (buffer);
165 len[0] = GST_BUFFER_MEM_LEN (buffer);
168 size = gst_buffer_get_size (buffer);
170 span = _gst_buffer_arr_span (mem, len, 1, offset, size, writable);
176 _replace_memory (GstBuffer * buffer, GstMemory * mem)
180 /* unref old buffers */
181 len = GST_BUFFER_MEM_LEN (buffer);
182 for (i = 0; i < len; i++)
183 gst_memory_unref (GST_BUFFER_MEM_PTR (buffer, i));
185 /* replace with single spanned buffer */
186 GST_BUFFER_MEM_PTR (buffer, 0) = mem;
187 GST_BUFFER_MEM_LEN (buffer) = 1;
191 _memory_add (GstBuffer * buffer, guint idx, GstMemory * mem)
193 guint i, len = GST_BUFFER_MEM_LEN (buffer);
195 if (G_UNLIKELY (len >= GST_BUFFER_MEM_MAX)) {
196 /* too many buffer, span them. */
197 /* FIXME, there is room for improvement here: We could only try to merge
198 * 2 buffers to make some room. If we can't efficiently merge 2 buffers we
199 * could try to only merge the two smallest buffers to avoid memcpy, etc. */
200 _replace_memory (buffer, _span_memory (buffer, 0, -1, FALSE));
201 /* we now have 1 single spanned buffer */
208 for (i = len; i > idx; i--) {
209 /* move buffers to insert, FIXME, we need to insert first and then merge */
210 GST_BUFFER_MEM_PTR (buffer, i) = GST_BUFFER_MEM_PTR (buffer, i - 1);
212 /* and insert the new buffer */
213 GST_BUFFER_MEM_PTR (buffer, idx) = mem;
214 GST_BUFFER_MEM_LEN (buffer) = len + 1;
217 GST_DEFINE_MINI_OBJECT_TYPE (GstBuffer, gst_buffer);
220 _priv_gst_buffer_initialize (void)
222 _gst_buffer_type = gst_buffer_get_type ();
226 * gst_buffer_copy_into:
227 * @dest: a destination #GstBuffer
228 * @src: a source #GstBuffer
229 * @flags: flags indicating what metadata fields should be copied.
230 * @offset: offset to copy from
231 * @size: total size to copy. If -1, all data is copied.
233 * Copies the information from @src into @dest.
235 * @flags indicate which fields will be copied.
238 gst_buffer_copy_into (GstBuffer * dest, GstBuffer * src,
239 GstBufferCopyFlags flags, gsize offset, gsize size)
244 g_return_if_fail (dest != NULL);
245 g_return_if_fail (src != NULL);
247 /* nothing to copy if the buffers are the same */
248 if (G_UNLIKELY (dest == src))
251 g_return_if_fail (gst_buffer_is_writable (dest));
253 bufsize = gst_buffer_get_size (src);
254 g_return_if_fail (bufsize >= offset);
256 size = bufsize - offset;
257 g_return_if_fail (bufsize >= offset + size);
259 GST_CAT_LOG (GST_CAT_BUFFER, "copy %p to %p, offset %" G_GSIZE_FORMAT
260 "-%" G_GSIZE_FORMAT "/%" G_GSIZE_FORMAT, src, dest, offset, size,
263 if (flags & GST_BUFFER_COPY_FLAGS) {
265 GST_MINI_OBJECT_FLAGS (dest) = GST_MINI_OBJECT_FLAGS (src);
268 if (flags & GST_BUFFER_COPY_TIMESTAMPS) {
270 GST_BUFFER_PTS (dest) = GST_BUFFER_PTS (src);
271 GST_BUFFER_DTS (dest) = GST_BUFFER_DTS (src);
272 GST_BUFFER_OFFSET (dest) = GST_BUFFER_OFFSET (src);
273 if (size == bufsize) {
274 GST_BUFFER_DURATION (dest) = GST_BUFFER_DURATION (src);
275 GST_BUFFER_OFFSET_END (dest) = GST_BUFFER_OFFSET_END (src);
278 GST_BUFFER_PTS (dest) = GST_CLOCK_TIME_NONE;
279 GST_BUFFER_DTS (dest) = GST_CLOCK_TIME_NONE;
280 GST_BUFFER_DURATION (dest) = GST_CLOCK_TIME_NONE;
281 GST_BUFFER_OFFSET (dest) = GST_BUFFER_OFFSET_NONE;
282 GST_BUFFER_OFFSET_END (dest) = GST_BUFFER_OFFSET_NONE;
286 if (flags & GST_BUFFER_COPY_MEMORY) {
288 gsize skip, left, len, i, bsize;
290 len = GST_BUFFER_MEM_LEN (src);
294 /* copy and make regions of the memory */
295 for (i = 0; i < len && left > 0; i++) {
296 mem = GST_BUFFER_MEM_PTR (src, i);
297 bsize = gst_memory_get_sizes (mem, NULL, NULL);
300 /* don't copy buffer */
305 tocopy = MIN (bsize - skip, left);
306 if (mem->flags & GST_MEMORY_FLAG_NO_SHARE) {
307 /* no share, always copy then */
308 mem = gst_memory_copy (mem, skip, tocopy);
310 } else if (tocopy < bsize) {
311 /* we need to clip something */
312 mem = gst_memory_share (mem, skip, tocopy);
315 mem = gst_memory_ref (mem);
317 _memory_add (dest, -1, mem);
321 if (flags & GST_BUFFER_COPY_MERGE) {
322 _replace_memory (dest, _span_memory (dest, 0, size, FALSE));
326 for (walk = GST_BUFFER_META (src); walk; walk = walk->next) {
327 GstMeta *meta = &walk->meta;
328 const GstMetaInfo *info = meta->info;
331 info->copy_func (dest, meta, src, offset, size);
336 _gst_buffer_copy (GstBuffer * buffer)
340 g_return_val_if_fail (buffer != NULL, NULL);
342 /* create a fresh new buffer */
343 copy = gst_buffer_new ();
345 /* we simply copy everything from our parent */
346 gst_buffer_copy_into (copy, buffer, GST_BUFFER_COPY_ALL, 0, -1);
351 /* the default dispose function revives the buffer and returns it to the
352 * pool when there is a pool */
354 _gst_buffer_dispose (GstBuffer * buffer)
358 /* no pool, do free */
359 if ((pool = buffer->pool) == NULL)
362 /* keep the buffer alive */
363 gst_buffer_ref (buffer);
364 /* return the buffer to the pool */
365 GST_CAT_LOG (GST_CAT_BUFFER, "release %p to pool %p", buffer, pool);
366 gst_buffer_pool_release_buffer (pool, buffer);
372 _gst_buffer_free (GstBuffer * buffer)
374 GstMetaItem *walk, *next;
378 g_return_if_fail (buffer != NULL);
380 GST_CAT_LOG (GST_CAT_BUFFER, "finalize %p", buffer);
383 for (walk = GST_BUFFER_META (buffer); walk; walk = next) {
384 GstMeta *meta = &walk->meta;
385 const GstMetaInfo *info = meta->info;
387 /* call free_func if any */
389 info->free_func (meta, buffer);
392 /* and free the slice */
393 g_slice_free1 (ITEM_SIZE (info), walk);
396 /* get the size, when unreffing the memory, we could also unref the buffer
398 msize = GST_MINI_OBJECT_SIZE (buffer);
400 /* free our memory */
401 len = GST_BUFFER_MEM_LEN (buffer);
402 for (i = 0; i < len; i++)
403 gst_memory_unref (GST_BUFFER_MEM_PTR (buffer, i));
405 /* we set msize to 0 when the buffer is part of the memory block */
407 g_slice_free1 (msize, buffer);
409 gst_memory_unref (GST_BUFFER_BUFMEM (buffer));
413 gst_buffer_init (GstBufferImpl * buffer, gsize size)
415 gst_mini_object_init (GST_MINI_OBJECT_CAST (buffer), _gst_buffer_type, size);
417 buffer->buffer.mini_object.copy =
418 (GstMiniObjectCopyFunction) _gst_buffer_copy;
419 buffer->buffer.mini_object.dispose =
420 (GstMiniObjectDisposeFunction) _gst_buffer_dispose;
421 buffer->buffer.mini_object.free =
422 (GstMiniObjectFreeFunction) _gst_buffer_free;
424 GST_BUFFER (buffer)->pool = NULL;
425 GST_BUFFER_PTS (buffer) = GST_CLOCK_TIME_NONE;
426 GST_BUFFER_DTS (buffer) = GST_CLOCK_TIME_NONE;
427 GST_BUFFER_DURATION (buffer) = GST_CLOCK_TIME_NONE;
428 GST_BUFFER_OFFSET (buffer) = GST_BUFFER_OFFSET_NONE;
429 GST_BUFFER_OFFSET_END (buffer) = GST_BUFFER_OFFSET_NONE;
431 GST_BUFFER_MEM_LEN (buffer) = 0;
432 GST_BUFFER_META (buffer) = NULL;
438 * Creates a newly allocated buffer without any data.
442 * Returns: (transfer full): the new #GstBuffer.
445 gst_buffer_new (void)
447 GstBufferImpl *newbuf;
449 newbuf = g_slice_new (GstBufferImpl);
450 GST_CAT_LOG (GST_CAT_BUFFER, "new %p", newbuf);
452 gst_buffer_init (newbuf, sizeof (GstBufferImpl));
454 return GST_BUFFER_CAST (newbuf);
458 * gst_buffer_new_allocate:
459 * @allocator: (allow-none): the #GstAllocator to use, or NULL to use the
461 * @size: the size in bytes of the new buffer's data.
462 * @align: the alignment of the buffer memory
464 * Tries to create a newly allocated buffer with data of the given size and
465 * alignment from @allocator. If the requested amount of memory can't be
466 * allocated, NULL will be returned. The allocated buffer memory is not cleared.
468 * When @allocator is NULL, the default memory allocator will be used.
470 * Allocator buffer memory will be aligned to multiples of (@align + 1) bytes.
472 * Note that when @size == 0, the buffer will not have memory associated with it.
476 * Returns: (transfer full): a new #GstBuffer, or NULL if the memory couldn't
480 gst_buffer_new_allocate (const GstAllocator * allocator, gsize size,
492 mem = gst_allocator_alloc (allocator, size, align);
493 if (G_UNLIKELY (mem == NULL))
499 newbuf = gst_buffer_new ();
502 _memory_add (newbuf, -1, mem);
504 GST_CAT_LOG (GST_CAT_BUFFER,
505 "new buffer %p of size %" G_GSIZE_FORMAT " from allocator %p", newbuf,
510 asize = sizeof (GstBufferImpl) + size;
511 data = g_slice_alloc (asize);
512 if (G_UNLIKELY (data == NULL))
515 newbuf = GST_BUFFER_CAST (data);
517 gst_buffer_init ((GstBufferImpl *) data, asize);
519 mem = gst_memory_new_wrapped (0, data + sizeof (GstBufferImpl), NULL,
521 _memory_add (newbuf, -1, mem);
526 /* allocate memory and buffer, it might be interesting to do this but there
527 * are many complications. We need to keep the memory mapped to access the
528 * buffer fields and the memory for the buffer might be just very slow. We
529 * also need to do some more magic to get the alignment right. */
530 asize = sizeof (GstBufferImpl) + size;
531 mem = gst_allocator_alloc (allocator, asize, align);
532 if (G_UNLIKELY (mem == NULL))
535 /* map the data part and init the buffer in it, set the buffer size to 0 so
536 * that a finalize won't free the buffer */
537 data = gst_memory_map (mem, &asize, NULL, GST_MAP_WRITE);
538 gst_buffer_init ((GstBufferImpl *) data, 0);
539 gst_memory_unmap (mem, data, asize);
541 /* strip off the buffer */
542 gst_memory_resize (mem, sizeof (GstBufferImpl), size);
544 newbuf = GST_BUFFER_CAST (data);
545 GST_BUFFER_BUFMEM (newbuf) = mem;
548 _memory_add (newbuf, -1, gst_memory_ref (mem));
556 GST_CAT_WARNING (GST_CAT_BUFFER,
557 "failed to allocate %" G_GSIZE_FORMAT " bytes", size);
563 * gst_buffer_new_wrapped_full:
564 * @data: data to wrap
565 * @free_func: function to free @data
566 * @offset: offset in @data of valid data
567 * @size: size of valid data in @data starting at @offset
569 * Creates a new buffer that wraps the given @data. Valid data is set
570 * to start at @offset and up to @size. If no @free_func is provided,
571 * buffer memory is marked READONLY.
575 * Returns: (transfer full): a new #GstBuffer
578 gst_buffer_new_wrapped_full (gpointer data, GFreeFunc free_func, gsize offset,
583 newbuf = gst_buffer_new ();
584 gst_buffer_take_memory (newbuf, -1,
585 gst_memory_new_wrapped (free_func ? 0 : GST_MEMORY_FLAG_READONLY,
586 data, free_func, offset + size, offset, size));
592 * gst_buffer_new_wrapped:
593 * @data: data to wrap
594 * @size: allocated size of @data
596 * Creates a new buffer that wraps the given @data. The memory will be freed
597 * with g_free and will be marked writable.
601 * Returns: (transfer full): a new #GstBuffer
604 gst_buffer_new_wrapped (gpointer data, gsize size)
606 return gst_buffer_new_wrapped_full (data, g_free, 0, size);
610 * gst_buffer_n_memory:
611 * @buffer: a #GstBuffer.
613 * Get the amount of memory blocks that this buffer has.
615 * Returns: (transfer full): the amount of memory block in this buffer.
618 gst_buffer_n_memory (GstBuffer * buffer)
620 g_return_val_if_fail (GST_IS_BUFFER (buffer), 0);
622 return GST_BUFFER_MEM_LEN (buffer);
626 * gst_buffer_take_memory:
627 * @buffer: a #GstBuffer.
628 * @idx: the index to add the memory at, or -1 to append it to the end
629 * @mem: (transfer full): a #GstMemory.
631 * Add the memory block @mem to @buffer at @idx. This function takes ownership
632 * of @mem and thus doesn't increase its refcount.
635 gst_buffer_take_memory (GstBuffer * buffer, gint idx, GstMemory * mem)
637 g_return_if_fail (GST_IS_BUFFER (buffer));
638 g_return_if_fail (gst_buffer_is_writable (buffer));
639 g_return_if_fail (mem != NULL);
640 g_return_if_fail (idx == -1 ||
641 (idx >= 0 && idx <= GST_BUFFER_MEM_LEN (buffer)));
643 _memory_add (buffer, idx, mem);
647 _get_memory (GstBuffer * buffer, guint idx, gboolean write)
651 mem = GST_BUFFER_MEM_PTR (buffer, idx);
653 if (G_UNLIKELY (write && !GST_MEMORY_IS_WRITABLE (mem))) {
655 GST_CAT_LOG (GST_CAT_BUFFER,
656 "making writable copy of memory %p in buffer %p", mem, buffer);
657 /* replace with a writable copy */
658 copy = gst_memory_copy (mem, 0, -1);
659 GST_BUFFER_MEM_PTR (buffer, idx) = copy;
660 gst_memory_unref (mem);
667 * gst_buffer_peek_memory:
668 * @buffer: a #GstBuffer.
670 * @flags: #GstMapFlags
672 * Get the memory block in @buffer at @idx for memory access in @flags.
673 * This function does not return a refcount to the memory block. The memory
674 * block stays valid for as long as the caller has a valid reference to @buffer.
676 * @buffer should be writable when @flags contains #GST_MAP_WRITE. If the memory
677 * at @idx is not writable, a new writable copy will be installed in @buffer and
680 * Returns: a #GstMemory at @idx.
683 gst_buffer_peek_memory (GstBuffer * buffer, guint idx, GstMapFlags flags)
688 write = (flags & GST_MAP_WRITE) != 0;
690 g_return_val_if_fail (GST_IS_BUFFER (buffer), NULL);
691 g_return_val_if_fail (idx < GST_BUFFER_MEM_LEN (buffer), NULL);
693 /* check if we can write when asked for write access */
694 if (G_UNLIKELY (write && !gst_buffer_is_writable (buffer)))
697 mem = _get_memory (buffer, idx, write);
704 g_return_val_if_fail (gst_buffer_is_writable (buffer), NULL);
710 * gst_buffer_remove_memory_range:
711 * @buffer: a #GstBuffer.
715 * Remove @len memory blocks in @buffer starting from @idx.
717 * @length can be -1, in which case all memory starting from @idx is removed.
720 gst_buffer_remove_memory_range (GstBuffer * buffer, guint idx, guint length)
724 g_return_if_fail (GST_IS_BUFFER (buffer));
725 g_return_if_fail (gst_buffer_is_writable (buffer));
727 len = GST_BUFFER_MEM_LEN (buffer);
729 g_return_if_fail (idx < len);
734 for (i = idx; i < end; i++)
735 gst_memory_unref (GST_BUFFER_MEM_PTR (buffer, i));
738 g_memmove (&GST_BUFFER_MEM_PTR (buffer, idx),
739 &GST_BUFFER_MEM_PTR (buffer, end), (len - end) * sizeof (gpointer));
741 GST_BUFFER_MEM_LEN (buffer) = len - length;
745 * gst_buffer_get_sizes:
746 * @buffer: a #GstBuffer.
747 * @offset: a pointer to the offset
748 * @maxsize: a pointer to the maxsize
750 * Get the total size of all memory blocks in @buffer.
752 * When not %NULL, @offset will contain the offset of the data in the first
753 * memory block in @buffer and @maxsize will contain the sum of the size
754 * and @offset and the amount of extra padding on the last memory block.
755 * @offset and @maxsize can be used to resize the buffer with
756 * gst_buffer_resize().
758 * Returns: the total size of the memory in @buffer.
761 gst_buffer_get_sizes (GstBuffer * buffer, gsize * offset, gsize * maxsize)
767 g_return_val_if_fail (GST_IS_BUFFER (buffer), 0);
769 len = GST_BUFFER_MEM_LEN (buffer);
771 if (G_LIKELY (len == 1)) {
773 mem = GST_BUFFER_MEM_PTR (buffer, 0);
774 size = gst_memory_get_sizes (mem, offset, maxsize);
779 size = offs = extra = 0;
780 for (i = 0; i < len; i++) {
783 mem = GST_BUFFER_MEM_PTR (buffer, i);
784 s = gst_memory_get_sizes (mem, &o, &ms);
788 /* first size, take accumulated data before as the offset */
792 /* save the amount of data after this block */
793 extra = ms - (o + s);
795 /* empty block, add as extra */
802 *maxsize = offs + size + extra;
809 * @buffer: a #GstBuffer.
810 * @offset: the offset adjustement
811 * @size: the new size or -1 to just adjust the offset
813 * Set the total size of the buffer
816 gst_buffer_resize (GstBuffer * buffer, gssize offset, gssize size)
820 gsize bsize, bufsize, bufoffs, bufmax;
823 g_return_if_fail (gst_buffer_is_writable (buffer));
824 g_return_if_fail (size >= -1);
826 bufsize = gst_buffer_get_sizes (buffer, &bufoffs, &bufmax);
828 GST_CAT_LOG (GST_CAT_BUFFER, "trim %p %" G_GSSIZE_FORMAT "-%" G_GSSIZE_FORMAT
829 " size:%" G_GSIZE_FORMAT " offs:%" G_GSIZE_FORMAT " max:%"
830 G_GSIZE_FORMAT, buffer, offset, size, bufsize, bufoffs, bufmax);
832 /* we can't go back further than the current offset or past the end of the
834 g_return_if_fail ((offset < 0 && bufoffs >= -offset) || (offset >= 0
835 && bufoffs + offset <= bufmax));
837 g_return_if_fail (bufsize >= offset);
838 size = bufsize - offset;
840 g_return_if_fail (bufmax >= bufoffs + offset + size);
842 len = GST_BUFFER_MEM_LEN (buffer);
845 for (i = 0; i < len; i++) {
848 mem = GST_BUFFER_MEM_PTR (buffer, i);
849 bsize = gst_memory_get_sizes (mem, NULL, NULL);
852 /* last buffer always gets resized to the remaining size */
855 /* shrink buffers before the offset */
856 else if ((gssize) bsize <= offset) {
858 noffs = offset - bsize;
861 /* clip other buffers */
863 left = MIN (bsize - offset, size);
865 if (offset != 0 || left != bsize) {
866 /* we need to clip something */
867 if (GST_MEMORY_IS_WRITABLE (mem)) {
868 gst_memory_resize (mem, offset, left);
872 if (mem->flags & GST_MEMORY_FLAG_NO_SHARE)
873 tmp = gst_memory_copy (mem, offset, left);
875 tmp = gst_memory_share (mem, offset, left);
877 gst_memory_unref (mem);
884 GST_BUFFER_MEM_PTR (buffer, i) = mem;
890 * @buffer: a #GstBuffer.
891 * @size: (out) (allow-none): a location for the size
892 * @maxsize: (out) (allow-none): a location for the max size
893 * @flags: flags for the mapping
895 * This function return a pointer to the memory in @buffer. @flags describe the
896 * desired access of the memory. When @flags is #GST_MAP_WRITE, @buffer should
897 * be writable (as returned from gst_buffer_is_writable()).
899 * @size and @maxsize will contain the current valid number of bytes in the
900 * returned memory area and the total maximum mount of bytes available in the
901 * returned memory area respectively. Both parameters can be %NULL.
903 * When @buffer is writable but the memory isn't, a writable copy will
904 * automatically be created and returned. The readonly copy of the buffer memory
905 * will then also be replaced with this writable copy.
907 * When the buffer contains multiple memory blocks, the returned pointer will be
908 * a concatenation of the memory blocks.
910 * Returns: (transfer none): a pointer to the memory for the buffer.
913 gst_buffer_map (GstBuffer * buffer, gsize * size, gsize * maxsize,
919 gboolean write, writable;
921 g_return_val_if_fail (GST_IS_BUFFER (buffer), NULL);
923 write = (flags & GST_MAP_WRITE) != 0;
924 writable = gst_buffer_is_writable (buffer);
926 /* check if we can write when asked for write access */
927 if (G_UNLIKELY (write && !writable))
930 len = GST_BUFFER_MEM_LEN (buffer);
932 if (G_UNLIKELY (len == 0)) {
933 /* no memory, return immediately */
941 if (G_LIKELY (len == 1)) {
942 /* we can take the first one */
943 mem = GST_BUFFER_MEM_PTR (buffer, 0);
945 /* we need to span memory */
947 /* if we can write, we can change the memory with the spanned
949 mem = _span_memory (buffer, 0, -1, write);
950 _replace_memory (buffer, mem);
954 /* extract all data in new memory, FIXME slow!! */
955 bsize = gst_buffer_get_size (buffer);
957 data = g_malloc (bsize);
958 gst_buffer_extract (buffer, 0, data, bsize);
967 if (G_UNLIKELY (write && !GST_MEMORY_IS_WRITABLE (mem))) {
969 /* replace with a writable copy */
970 copy = gst_memory_copy (mem, 0, -1);
971 GST_BUFFER_MEM_PTR (buffer, 0) = copy;
972 gst_memory_unref (mem);
976 data = gst_memory_map (mem, size, maxsize, flags);
983 g_return_val_if_fail (gst_buffer_is_writable (buffer), NULL);
990 * @buffer: a #GstBuffer.
991 * @data: the previously mapped data
992 * @size: the size of @data, or -1
994 * Release the memory previously mapped with gst_buffer_map(). Pass -1 to size
995 * if no update is needed.
997 * Returns: #TRUE on success. #FALSE can be returned when the new size is larger
998 * than the maxsize of the memory.
1001 gst_buffer_unmap (GstBuffer * buffer, gpointer data, gssize size)
1006 g_return_val_if_fail (GST_IS_BUFFER (buffer), FALSE);
1007 g_return_val_if_fail (size >= -1, FALSE);
1009 len = GST_BUFFER_MEM_LEN (buffer);
1011 if (G_LIKELY (len == 1)) {
1012 GstMemory *mem = GST_BUFFER_MEM_PTR (buffer, 0);
1014 result = gst_memory_unmap (mem, data, size);
1016 /* this must have been from read-only access. After _map, the buffer either
1017 * only contains 1 memory block or it allocated memory to join memory
1018 * blocks. It's not allowed to add buffers between _map and _unmap. */
1027 * @buffer: a #GstBuffer.
1028 * @offset: the offset to fill
1029 * @src: the source address
1030 * @size: the size to fill
1032 * Copy @size bytes from @src to @buffer at @offset.
1034 * Returns: The amount of bytes copied. This value can be lower than @size
1035 * when @buffer did not contain enough data.
1038 gst_buffer_fill (GstBuffer * buffer, gsize offset, gconstpointer src,
1042 const guint8 *ptr = src;
1044 g_return_val_if_fail (GST_IS_BUFFER (buffer), 0);
1045 g_return_val_if_fail (gst_buffer_is_writable (buffer), 0);
1046 g_return_val_if_fail (src != NULL, 0);
1048 len = GST_BUFFER_MEM_LEN (buffer);
1051 for (i = 0; i < len && left > 0; i++) {
1053 gsize ssize, tocopy;
1056 mem = _get_memory (buffer, i, TRUE);
1058 data = gst_memory_map (mem, &ssize, NULL, GST_MAP_WRITE);
1059 if (ssize > offset) {
1060 /* we have enough */
1061 tocopy = MIN (ssize - offset, left);
1062 memcpy (data + offset, ptr, tocopy);
1067 /* offset past buffer, skip */
1070 gst_memory_unmap (mem, data, ssize);
1076 * gst_buffer_extract:
1077 * @buffer: a #GstBuffer.
1078 * @offset: the offset to extract
1079 * @dest: the destination address
1080 * @size: the size to extract
1082 * Copy @size bytes starting from @offset in @buffer to @dest.
1084 * Returns: The amount of bytes extracted. This value can be lower than @size
1085 * when @buffer did not contain enough data.
1088 gst_buffer_extract (GstBuffer * buffer, gsize offset, gpointer dest, gsize size)
1093 g_return_val_if_fail (GST_IS_BUFFER (buffer), 0);
1094 g_return_val_if_fail (dest != NULL, 0);
1096 len = GST_BUFFER_MEM_LEN (buffer);
1099 for (i = 0; i < len && left > 0; i++) {
1101 gsize ssize, tocopy;
1104 mem = GST_BUFFER_MEM_PTR (buffer, i);
1106 data = gst_memory_map (mem, &ssize, NULL, GST_MAP_READ);
1107 if (ssize > offset) {
1108 /* we have enough */
1109 tocopy = MIN (ssize - offset, left);
1110 memcpy (ptr, data + offset, tocopy);
1115 /* offset past buffer, skip */
1118 gst_memory_unmap (mem, data, ssize);
1124 * gst_buffer_memcmp:
1125 * @buffer: a #GstBuffer.
1126 * @offset: the offset in @buffer
1127 * @mem: the memory to compare
1128 * @size: the size to compare
1130 * Compare @size bytes starting from @offset in @buffer with the memory in @mem.
1132 * Returns: 0 if the memory is equal.
1135 gst_buffer_memcmp (GstBuffer * buffer, gsize offset, gconstpointer mem,
1139 const guint8 *ptr = mem;
1142 g_return_val_if_fail (GST_IS_BUFFER (buffer), 0);
1143 g_return_val_if_fail (mem != NULL, 0);
1145 len = GST_BUFFER_MEM_LEN (buffer);
1147 for (i = 0; i < len && size > 0 && res == 0; i++) {
1152 mem = GST_BUFFER_MEM_PTR (buffer, i);
1154 data = gst_memory_map (mem, &ssize, NULL, GST_MAP_READ);
1155 if (ssize > offset) {
1156 /* we have enough */
1157 tocmp = MIN (ssize - offset, size);
1158 res = memcmp (ptr, data + offset, tocmp);
1163 /* offset past buffer, skip */
1166 gst_memory_unmap (mem, data, ssize);
1172 * gst_buffer_memset:
1173 * @buffer: a #GstBuffer.
1174 * @offset: the offset in @buffer
1175 * @val: the value to set
1176 * @size: the size to set
1178 * Fill @buf with @size bytes with @val starting from @offset.
1180 * Returns: The amount of bytes filled. This value can be lower than @size
1181 * when @buffer did not contain enough data.
1184 gst_buffer_memset (GstBuffer * buffer, gsize offset, guint8 val, gsize size)
1188 g_return_val_if_fail (GST_IS_BUFFER (buffer), 0);
1189 g_return_val_if_fail (gst_buffer_is_writable (buffer), 0);
1191 len = GST_BUFFER_MEM_LEN (buffer);
1194 for (i = 0; i < len && left > 0; i++) {
1199 mem = GST_BUFFER_MEM_PTR (buffer, i);
1201 data = gst_memory_map (mem, &ssize, NULL, GST_MAP_WRITE);
1202 if (ssize > offset) {
1203 /* we have enough */
1204 toset = MIN (ssize - offset, left);
1205 memset (data + offset, val, toset);
1209 /* offset past buffer, skip */
1212 gst_memory_unmap (mem, data, ssize);
1218 * gst_buffer_copy_region:
1219 * @parent: a #GstBuffer.
1220 * @flags: the #GstBufferCopyFlags
1221 * @offset: the offset into parent #GstBuffer at which the new sub-buffer
1223 * @size: the size of the new #GstBuffer sub-buffer, in bytes.
1225 * Creates a sub-buffer from @parent at @offset and @size.
1226 * This sub-buffer uses the actual memory space of the parent buffer.
1227 * This function will copy the offset and timestamp fields when the
1228 * offset is 0. If not, they will be set to #GST_CLOCK_TIME_NONE and
1229 * #GST_BUFFER_OFFSET_NONE.
1230 * If @offset equals 0 and @size equals the total size of @buffer, the
1231 * duration and offset end fields are also copied. If not they will be set
1232 * to #GST_CLOCK_TIME_NONE and #GST_BUFFER_OFFSET_NONE.
1236 * Returns: (transfer full): the new #GstBuffer or NULL if the arguments were
1240 gst_buffer_copy_region (GstBuffer * buffer, GstBufferCopyFlags flags,
1241 gsize offset, gsize size)
1245 g_return_val_if_fail (buffer != NULL, NULL);
1247 /* create the new buffer */
1248 copy = gst_buffer_new ();
1250 GST_CAT_LOG (GST_CAT_BUFFER, "new region copy %p of %p %" G_GSIZE_FORMAT
1251 "-%" G_GSIZE_FORMAT, copy, buffer, offset, size);
1253 gst_buffer_copy_into (copy, buffer, flags, offset, size);
1259 _gst_buffer_arr_is_span_fast (GstMemory ** mem[], gsize len[], guint n,
1260 gsize * offset, GstMemory ** parent)
1262 GstMemory *mcur, *mprv;
1263 gboolean have_offset = FALSE;
1267 for (count = 0; count < n; count++) {
1274 for (i = 0; i < clen; i++) {
1280 /* check is memory is contiguous */
1281 if (!gst_memory_is_span (mprv, mcur, &offs))
1288 *parent = mprv->parent;
1299 _gst_buffer_arr_span (GstMemory ** mem[], gsize len[], guint n, gsize offset,
1300 gsize size, gboolean writable)
1302 GstMemory *span, *parent = NULL;
1306 && _gst_buffer_arr_is_span_fast (mem, len, n, &poffset, &parent)) {
1307 if (parent->flags & GST_MEMORY_FLAG_NO_SHARE)
1308 span = gst_memory_copy (parent, offset + poffset, size);
1310 span = gst_memory_share (parent, offset + poffset, size);
1315 span = gst_allocator_alloc (NULL, size, 0);
1316 dest = gst_memory_map (span, NULL, NULL, GST_MAP_WRITE);
1321 for (count = 0; count < n; count++) {
1322 gsize i, tocopy, clen, ssize;
1329 for (i = 0; i < clen && left > 0; i++) {
1330 src = gst_memory_map (cmem[i], &ssize, NULL, GST_MAP_READ);
1331 tocopy = MIN (ssize, left);
1332 if (tocopy > offset) {
1333 memcpy (ptr, src + offset, tocopy - offset);
1340 gst_memory_unmap (cmem[i], src, ssize);
1343 gst_memory_unmap (span, dest, size);
1349 * gst_buffer_is_span_fast:
1350 * @buf1: the first #GstBuffer.
1351 * @buf2: the second #GstBuffer.
1353 * Determines whether a gst_buffer_span() can be done without copying
1354 * the contents, that is, whether the data areas are contiguous sub-buffers of
1358 * Returns: TRUE if the buffers are contiguous,
1359 * FALSE if a copy would be required.
1362 gst_buffer_is_span_fast (GstBuffer * buf1, GstBuffer * buf2)
1367 g_return_val_if_fail (GST_IS_BUFFER (buf1), FALSE);
1368 g_return_val_if_fail (GST_IS_BUFFER (buf2), FALSE);
1369 g_return_val_if_fail (buf1->mini_object.refcount > 0, FALSE);
1370 g_return_val_if_fail (buf2->mini_object.refcount > 0, FALSE);
1372 mem[0] = GST_BUFFER_MEM_ARRAY (buf1);
1373 len[0] = GST_BUFFER_MEM_LEN (buf1);
1374 mem[1] = GST_BUFFER_MEM_ARRAY (buf2);
1375 len[1] = GST_BUFFER_MEM_LEN (buf2);
1377 return _gst_buffer_arr_is_span_fast (mem, len, 2, NULL, NULL);
1382 * @buf1: the first source #GstBuffer to merge.
1383 * @offset: the offset in the first buffer from where the new
1384 * buffer should start.
1385 * @buf2: the second source #GstBuffer to merge.
1386 * @size: the total size of the new buffer.
1388 * Creates a new buffer that consists of part of buf1 and buf2.
1389 * Logically, buf1 and buf2 are concatenated into a single larger
1390 * buffer, and a new buffer is created at the given offset inside
1391 * this space, with a given length.
1393 * If the two source buffers are children of the same larger buffer,
1394 * and are contiguous, the new buffer will be a child of the shared
1395 * parent, and thus no copying is necessary. you can use
1396 * gst_buffer_is_span_fast() to determine if a memcpy will be needed.
1400 * Returns: (transfer full): the new #GstBuffer that spans the two source
1401 * buffers, or NULL if the arguments are invalid.
1404 gst_buffer_span (GstBuffer * buf1, gsize offset, GstBuffer * buf2, gsize size)
1409 gsize len[2], len1, len2;
1411 g_return_val_if_fail (GST_IS_BUFFER (buf1), NULL);
1412 g_return_val_if_fail (GST_IS_BUFFER (buf2), NULL);
1413 g_return_val_if_fail (buf1->mini_object.refcount > 0, NULL);
1414 g_return_val_if_fail (buf2->mini_object.refcount > 0, NULL);
1415 len1 = gst_buffer_get_size (buf1);
1416 len2 = gst_buffer_get_size (buf2);
1417 g_return_val_if_fail (len1 + len2 > offset, NULL);
1419 size = len1 + len2 - offset;
1421 g_return_val_if_fail (size <= len1 + len2 - offset, NULL);
1423 mem[0] = GST_BUFFER_MEM_ARRAY (buf1);
1424 len[0] = GST_BUFFER_MEM_LEN (buf1);
1425 mem[1] = GST_BUFFER_MEM_ARRAY (buf2);
1426 len[1] = GST_BUFFER_MEM_LEN (buf2);
1428 span = _gst_buffer_arr_span (mem, len, 2, offset, size, FALSE);
1430 newbuf = gst_buffer_new ();
1431 _memory_add (newbuf, -1, span);
1434 /* if the offset is 0, the new buffer has the same timestamp as buf1 */
1436 GST_BUFFER_OFFSET (newbuf) = GST_BUFFER_OFFSET (buf1);
1437 GST_BUFFER_PTS (newbuf) = GST_BUFFER_PTS (buf1);
1438 GST_BUFFER_DTS (newbuf) = GST_BUFFER_DTS (buf1);
1440 /* if we completely merged the two buffers (appended), we can
1441 * calculate the duration too. Also make sure we's not messing with
1442 * invalid DURATIONS */
1443 if (buf1->size + buf2->size == len) {
1444 if (GST_BUFFER_DURATION_IS_VALID (buf1) &&
1445 GST_BUFFER_DURATION_IS_VALID (buf2)) {
1447 GST_BUFFER_DURATION (newbuf) = GST_BUFFER_DURATION (buf1) +
1448 GST_BUFFER_DURATION (buf2);
1450 if (GST_BUFFER_OFFSET_END_IS_VALID (buf2)) {
1451 /* add offset_end */
1452 GST_BUFFER_OFFSET_END (newbuf) = GST_BUFFER_OFFSET_END (buf2);
1462 * gst_buffer_get_meta:
1463 * @buffer: a #GstBuffer
1464 * @info: a #GstMetaInfo
1466 * Get the metadata for the api in @info on buffer. When there is no such
1467 * metadata, NULL is returned.
1469 * Note that the result metadata might not be of the implementation @info.
1471 * Returns: the metadata for the api in @info on @buffer.
1474 gst_buffer_get_meta (GstBuffer * buffer, const GstMetaInfo * info)
1477 GstMeta *result = NULL;
1479 g_return_val_if_fail (buffer != NULL, NULL);
1480 g_return_val_if_fail (info != NULL, NULL);
1482 /* find GstMeta of the requested API */
1483 for (item = GST_BUFFER_META (buffer); item; item = item->next) {
1484 GstMeta *meta = &item->meta;
1485 if (meta->info->api == info->api) {
1494 * gst_buffer_add_meta:
1495 * @buffer: a #GstBuffer
1496 * @info: a #GstMetaInfo
1497 * @params: params for @info
1499 * Add metadata for @info to @buffer using the parameters in @params.
1501 * Returns: (transfer none): the metadata for the api in @info on @buffer.
1504 gst_buffer_add_meta (GstBuffer * buffer, const GstMetaInfo * info,
1508 GstMeta *result = NULL;
1511 g_return_val_if_fail (buffer != NULL, NULL);
1512 g_return_val_if_fail (info != NULL, NULL);
1514 /* create a new slice */
1515 GST_CAT_DEBUG (GST_CAT_BUFFER, "alloc metadata %s of size %" G_GSIZE_FORMAT,
1516 g_type_name (info->type), info->size);
1518 size = ITEM_SIZE (info);
1519 item = g_slice_alloc (size);
1520 result = &item->meta;
1521 result->info = info;
1523 /* call the init_func when needed */
1524 if (info->init_func)
1525 if (!info->init_func (result, params, buffer))
1528 /* and add to the list of metadata */
1529 item->next = GST_BUFFER_META (buffer);
1530 GST_BUFFER_META (buffer) = item;
1536 g_slice_free1 (size, item);
1542 * gst_buffer_remove_meta:
1543 * @buffer: a #GstBuffer
1546 * Remove the metadata for @meta on @buffer.
1548 * Returns: %TRUE if the metadata existed and was removed, %FALSE if no such
1549 * metadata was on @buffer.
1552 gst_buffer_remove_meta (GstBuffer * buffer, GstMeta * meta)
1554 GstMetaItem *walk, *prev;
1556 g_return_val_if_fail (buffer != NULL, FALSE);
1557 g_return_val_if_fail (meta != NULL, FALSE);
1559 /* find the metadata and delete */
1560 prev = GST_BUFFER_META (buffer);
1561 for (walk = prev; walk; walk = walk->next) {
1562 GstMeta *m = &walk->meta;
1564 const GstMetaInfo *info = meta->info;
1566 /* remove from list */
1567 if (GST_BUFFER_META (buffer) == walk)
1568 GST_BUFFER_META (buffer) = walk->next;
1570 prev->next = walk->next;
1571 /* call free_func if any */
1572 if (info->free_func)
1573 info->free_func (m, buffer);
1575 /* and free the slice */
1576 g_slice_free1 (ITEM_SIZE (info), walk);
1581 return walk != NULL;
1585 * gst_buffer_iterate_meta:
1586 * @buffer: a #GstBuffer
1587 * @state: an opaque state pointer
1589 * Retrieve the next #GstMeta after @current. If @state points
1590 * to %NULL, the first metadata is returned.
1592 * @state will be updated with an opage state pointer
1594 * Returns: The next #GstMeta or %NULL when there are no more items.
1597 gst_buffer_iterate_meta (GstBuffer * buffer, gpointer * state)
1601 g_return_val_if_fail (buffer != NULL, NULL);
1602 g_return_val_if_fail (state != NULL, NULL);
1604 meta = (GstMetaItem **) state;
1606 /* state NULL, move to first item */
1607 *meta = GST_BUFFER_META (buffer);
1609 /* state !NULL, move to next item in list */
1610 *meta = (*meta)->next;
1613 return &(*meta)->meta;