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 if (flags & GST_BUFFER_COPY_META) {
327 for (walk = GST_BUFFER_META (src); walk; walk = walk->next) {
328 GstMeta *meta = &walk->meta;
329 const GstMetaInfo *info = meta->info;
332 info->copy_func (dest, meta, src, offset, size);
338 _gst_buffer_copy (GstBuffer * buffer)
342 g_return_val_if_fail (buffer != NULL, NULL);
344 /* create a fresh new buffer */
345 copy = gst_buffer_new ();
347 /* we simply copy everything from our parent */
348 gst_buffer_copy_into (copy, buffer, GST_BUFFER_COPY_ALL, 0, -1);
353 /* the default dispose function revives the buffer and returns it to the
354 * pool when there is a pool */
356 _gst_buffer_dispose (GstBuffer * buffer)
360 /* no pool, do free */
361 if ((pool = buffer->pool) == NULL)
364 /* keep the buffer alive */
365 gst_buffer_ref (buffer);
366 /* return the buffer to the pool */
367 GST_CAT_LOG (GST_CAT_BUFFER, "release %p to pool %p", buffer, pool);
368 gst_buffer_pool_release_buffer (pool, buffer);
374 _gst_buffer_free (GstBuffer * buffer)
376 GstMetaItem *walk, *next;
380 g_return_if_fail (buffer != NULL);
382 GST_CAT_LOG (GST_CAT_BUFFER, "finalize %p", buffer);
385 for (walk = GST_BUFFER_META (buffer); walk; walk = next) {
386 GstMeta *meta = &walk->meta;
387 const GstMetaInfo *info = meta->info;
389 /* call free_func if any */
391 info->free_func (meta, buffer);
394 /* and free the slice */
395 g_slice_free1 (ITEM_SIZE (info), walk);
398 /* get the size, when unreffing the memory, we could also unref the buffer
400 msize = GST_MINI_OBJECT_SIZE (buffer);
402 /* free our memory */
403 len = GST_BUFFER_MEM_LEN (buffer);
404 for (i = 0; i < len; i++)
405 gst_memory_unref (GST_BUFFER_MEM_PTR (buffer, i));
407 /* we set msize to 0 when the buffer is part of the memory block */
409 g_slice_free1 (msize, buffer);
411 gst_memory_unref (GST_BUFFER_BUFMEM (buffer));
415 gst_buffer_init (GstBufferImpl * buffer, gsize size)
417 gst_mini_object_init (GST_MINI_OBJECT_CAST (buffer), _gst_buffer_type, size);
419 buffer->buffer.mini_object.copy =
420 (GstMiniObjectCopyFunction) _gst_buffer_copy;
421 buffer->buffer.mini_object.dispose =
422 (GstMiniObjectDisposeFunction) _gst_buffer_dispose;
423 buffer->buffer.mini_object.free =
424 (GstMiniObjectFreeFunction) _gst_buffer_free;
426 GST_BUFFER (buffer)->pool = NULL;
427 GST_BUFFER_PTS (buffer) = GST_CLOCK_TIME_NONE;
428 GST_BUFFER_DTS (buffer) = GST_CLOCK_TIME_NONE;
429 GST_BUFFER_DURATION (buffer) = GST_CLOCK_TIME_NONE;
430 GST_BUFFER_OFFSET (buffer) = GST_BUFFER_OFFSET_NONE;
431 GST_BUFFER_OFFSET_END (buffer) = GST_BUFFER_OFFSET_NONE;
433 GST_BUFFER_MEM_LEN (buffer) = 0;
434 GST_BUFFER_META (buffer) = NULL;
440 * Creates a newly allocated buffer without any data.
444 * Returns: (transfer full): the new #GstBuffer.
447 gst_buffer_new (void)
449 GstBufferImpl *newbuf;
451 newbuf = g_slice_new (GstBufferImpl);
452 GST_CAT_LOG (GST_CAT_BUFFER, "new %p", newbuf);
454 gst_buffer_init (newbuf, sizeof (GstBufferImpl));
456 return GST_BUFFER_CAST (newbuf);
460 * gst_buffer_new_allocate:
461 * @allocator: (allow-none): the #GstAllocator to use, or NULL to use the
463 * @size: the size in bytes of the new buffer's data.
464 * @align: the alignment of the buffer memory
466 * Tries to create a newly allocated buffer with data of the given size and
467 * alignment from @allocator. If the requested amount of memory can't be
468 * allocated, NULL will be returned. The allocated buffer memory is not cleared.
470 * When @allocator is NULL, the default memory allocator will be used.
472 * Allocator buffer memory will be aligned to multiples of (@align + 1) bytes.
474 * Note that when @size == 0, the buffer will not have memory associated with it.
478 * Returns: (transfer full): a new #GstBuffer, or NULL if the memory couldn't
482 gst_buffer_new_allocate (const GstAllocator * allocator, gsize size,
494 mem = gst_allocator_alloc (allocator, size, align);
495 if (G_UNLIKELY (mem == NULL))
501 newbuf = gst_buffer_new ();
504 _memory_add (newbuf, -1, mem);
506 GST_CAT_LOG (GST_CAT_BUFFER,
507 "new buffer %p of size %" G_GSIZE_FORMAT " from allocator %p", newbuf,
512 asize = sizeof (GstBufferImpl) + size;
513 data = g_slice_alloc (asize);
514 if (G_UNLIKELY (data == NULL))
517 newbuf = GST_BUFFER_CAST (data);
519 gst_buffer_init ((GstBufferImpl *) data, asize);
521 mem = gst_memory_new_wrapped (0, data + sizeof (GstBufferImpl), NULL,
523 _memory_add (newbuf, -1, mem);
528 /* allocate memory and buffer, it might be interesting to do this but there
529 * are many complications. We need to keep the memory mapped to access the
530 * buffer fields and the memory for the buffer might be just very slow. We
531 * also need to do some more magic to get the alignment right. */
532 asize = sizeof (GstBufferImpl) + size;
533 mem = gst_allocator_alloc (allocator, asize, align);
534 if (G_UNLIKELY (mem == NULL))
537 /* map the data part and init the buffer in it, set the buffer size to 0 so
538 * that a finalize won't free the buffer */
539 data = gst_memory_map (mem, &asize, NULL, GST_MAP_WRITE);
540 gst_buffer_init ((GstBufferImpl *) data, 0);
541 gst_memory_unmap (mem, data, asize);
543 /* strip off the buffer */
544 gst_memory_resize (mem, sizeof (GstBufferImpl), size);
546 newbuf = GST_BUFFER_CAST (data);
547 GST_BUFFER_BUFMEM (newbuf) = mem;
550 _memory_add (newbuf, -1, gst_memory_ref (mem));
558 GST_CAT_WARNING (GST_CAT_BUFFER,
559 "failed to allocate %" G_GSIZE_FORMAT " bytes", size);
565 * gst_buffer_new_wrapped_full:
566 * @data: data to wrap
567 * @free_func: function to free @data
568 * @offset: offset in @data of valid data
569 * @size: size of valid data in @data starting at @offset
571 * Creates a new buffer that wraps the given @data. Valid data is set
572 * to start at @offset and up to @size. If no @free_func is provided,
573 * buffer memory is marked READONLY.
577 * Returns: (transfer full): a new #GstBuffer
580 gst_buffer_new_wrapped_full (gpointer data, GFreeFunc free_func, gsize offset,
585 newbuf = gst_buffer_new ();
586 gst_buffer_take_memory (newbuf, -1,
587 gst_memory_new_wrapped (free_func ? 0 : GST_MEMORY_FLAG_READONLY,
588 data, free_func, offset + size, offset, size));
594 * gst_buffer_new_wrapped:
595 * @data: data to wrap
596 * @size: allocated size of @data
598 * Creates a new buffer that wraps the given @data. The memory will be freed
599 * with g_free and will be marked writable.
603 * Returns: (transfer full): a new #GstBuffer
606 gst_buffer_new_wrapped (gpointer data, gsize size)
608 return gst_buffer_new_wrapped_full (data, g_free, 0, size);
612 * gst_buffer_n_memory:
613 * @buffer: a #GstBuffer.
615 * Get the amount of memory blocks that this buffer has.
617 * Returns: (transfer full): the amount of memory block in this buffer.
620 gst_buffer_n_memory (GstBuffer * buffer)
622 g_return_val_if_fail (GST_IS_BUFFER (buffer), 0);
624 return GST_BUFFER_MEM_LEN (buffer);
628 * gst_buffer_take_memory:
629 * @buffer: a #GstBuffer.
630 * @idx: the index to add the memory at, or -1 to append it to the end
631 * @mem: (transfer full): a #GstMemory.
633 * Add the memory block @mem to @buffer at @idx. This function takes ownership
634 * of @mem and thus doesn't increase its refcount.
637 gst_buffer_take_memory (GstBuffer * buffer, gint idx, GstMemory * mem)
639 g_return_if_fail (GST_IS_BUFFER (buffer));
640 g_return_if_fail (gst_buffer_is_writable (buffer));
641 g_return_if_fail (mem != NULL);
642 g_return_if_fail (idx == -1 ||
643 (idx >= 0 && idx <= GST_BUFFER_MEM_LEN (buffer)));
645 _memory_add (buffer, idx, mem);
649 _get_memory (GstBuffer * buffer, guint idx, gboolean write)
653 mem = GST_BUFFER_MEM_PTR (buffer, idx);
655 if (G_UNLIKELY (write && !GST_MEMORY_IS_WRITABLE (mem))) {
657 GST_CAT_LOG (GST_CAT_BUFFER,
658 "making writable copy of memory %p in buffer %p", mem, buffer);
659 /* replace with a writable copy */
660 copy = gst_memory_copy (mem, 0, -1);
661 GST_BUFFER_MEM_PTR (buffer, idx) = copy;
662 gst_memory_unref (mem);
669 * gst_buffer_peek_memory:
670 * @buffer: a #GstBuffer.
672 * @flags: #GstMapFlags
674 * Get the memory block in @buffer at @idx for memory access in @flags.
675 * This function does not return a refcount to the memory block. The memory
676 * block stays valid for as long as the caller has a valid reference to @buffer.
678 * @buffer should be writable when @flags contains #GST_MAP_WRITE. If the memory
679 * at @idx is not writable, a new writable copy will be installed in @buffer and
682 * Returns: a #GstMemory at @idx.
685 gst_buffer_peek_memory (GstBuffer * buffer, guint idx, GstMapFlags flags)
690 write = (flags & GST_MAP_WRITE) != 0;
692 g_return_val_if_fail (GST_IS_BUFFER (buffer), NULL);
693 g_return_val_if_fail (idx < GST_BUFFER_MEM_LEN (buffer), NULL);
695 /* check if we can write when asked for write access */
696 if (G_UNLIKELY (write && !gst_buffer_is_writable (buffer)))
699 mem = _get_memory (buffer, idx, write);
706 g_return_val_if_fail (gst_buffer_is_writable (buffer), NULL);
712 * gst_buffer_remove_memory_range:
713 * @buffer: a #GstBuffer.
717 * Remove @len memory blocks in @buffer starting from @idx.
719 * @length can be -1, in which case all memory starting from @idx is removed.
722 gst_buffer_remove_memory_range (GstBuffer * buffer, guint idx, guint length)
726 g_return_if_fail (GST_IS_BUFFER (buffer));
727 g_return_if_fail (gst_buffer_is_writable (buffer));
729 len = GST_BUFFER_MEM_LEN (buffer);
731 g_return_if_fail (idx < len);
736 for (i = idx; i < end; i++)
737 gst_memory_unref (GST_BUFFER_MEM_PTR (buffer, i));
740 g_memmove (&GST_BUFFER_MEM_PTR (buffer, idx),
741 &GST_BUFFER_MEM_PTR (buffer, end), (len - end) * sizeof (gpointer));
743 GST_BUFFER_MEM_LEN (buffer) = len - length;
747 * gst_buffer_get_sizes:
748 * @buffer: a #GstBuffer.
749 * @offset: a pointer to the offset
750 * @maxsize: a pointer to the maxsize
752 * Get the total size of all memory blocks in @buffer.
754 * When not %NULL, @offset will contain the offset of the data in the first
755 * memory block in @buffer and @maxsize will contain the sum of the size
756 * and @offset and the amount of extra padding on the last memory block.
757 * @offset and @maxsize can be used to resize the buffer with
758 * gst_buffer_resize().
760 * Returns: the total size of the memory in @buffer.
763 gst_buffer_get_sizes (GstBuffer * buffer, gsize * offset, gsize * maxsize)
769 g_return_val_if_fail (GST_IS_BUFFER (buffer), 0);
771 len = GST_BUFFER_MEM_LEN (buffer);
773 if (G_LIKELY (len == 1)) {
775 mem = GST_BUFFER_MEM_PTR (buffer, 0);
776 size = gst_memory_get_sizes (mem, offset, maxsize);
781 size = offs = extra = 0;
782 for (i = 0; i < len; i++) {
785 mem = GST_BUFFER_MEM_PTR (buffer, i);
786 s = gst_memory_get_sizes (mem, &o, &ms);
790 /* first size, take accumulated data before as the offset */
794 /* save the amount of data after this block */
795 extra = ms - (o + s);
797 /* empty block, add as extra */
804 *maxsize = offs + size + extra;
811 * @buffer: a #GstBuffer.
812 * @offset: the offset adjustement
813 * @size: the new size or -1 to just adjust the offset
815 * Set the total size of the buffer
818 gst_buffer_resize (GstBuffer * buffer, gssize offset, gssize size)
822 gsize bsize, bufsize, bufoffs, bufmax;
825 g_return_if_fail (gst_buffer_is_writable (buffer));
826 g_return_if_fail (size >= -1);
828 bufsize = gst_buffer_get_sizes (buffer, &bufoffs, &bufmax);
830 GST_CAT_LOG (GST_CAT_BUFFER, "trim %p %" G_GSSIZE_FORMAT "-%" G_GSSIZE_FORMAT
831 " size:%" G_GSIZE_FORMAT " offs:%" G_GSIZE_FORMAT " max:%"
832 G_GSIZE_FORMAT, buffer, offset, size, bufsize, bufoffs, bufmax);
834 /* we can't go back further than the current offset or past the end of the
836 g_return_if_fail ((offset < 0 && bufoffs >= -offset) || (offset >= 0
837 && bufoffs + offset <= bufmax));
839 g_return_if_fail (bufsize >= offset);
840 size = bufsize - offset;
842 g_return_if_fail (bufmax >= bufoffs + offset + size);
844 len = GST_BUFFER_MEM_LEN (buffer);
847 for (i = 0; i < len; i++) {
850 mem = GST_BUFFER_MEM_PTR (buffer, i);
851 bsize = gst_memory_get_sizes (mem, NULL, NULL);
854 /* last buffer always gets resized to the remaining size */
857 /* shrink buffers before the offset */
858 else if ((gssize) bsize <= offset) {
860 noffs = offset - bsize;
863 /* clip other buffers */
865 left = MIN (bsize - offset, size);
867 if (offset != 0 || left != bsize) {
868 /* we need to clip something */
869 if (GST_MEMORY_IS_WRITABLE (mem)) {
870 gst_memory_resize (mem, offset, left);
874 if (mem->flags & GST_MEMORY_FLAG_NO_SHARE)
875 tmp = gst_memory_copy (mem, offset, left);
877 tmp = gst_memory_share (mem, offset, left);
879 gst_memory_unref (mem);
886 GST_BUFFER_MEM_PTR (buffer, i) = mem;
892 * @buffer: a #GstBuffer.
893 * @size: (out) (allow-none): a location for the size
894 * @maxsize: (out) (allow-none): a location for the max size
895 * @flags: flags for the mapping
897 * This function return a pointer to the memory in @buffer. @flags describe the
898 * desired access of the memory. When @flags is #GST_MAP_WRITE, @buffer should
899 * be writable (as returned from gst_buffer_is_writable()).
901 * @size and @maxsize will contain the current valid number of bytes in the
902 * returned memory area and the total maximum mount of bytes available in the
903 * returned memory area respectively. Both parameters can be %NULL.
905 * When @buffer is writable but the memory isn't, a writable copy will
906 * automatically be created and returned. The readonly copy of the buffer memory
907 * will then also be replaced with this writable copy.
909 * When the buffer contains multiple memory blocks, the returned pointer will be
910 * a concatenation of the memory blocks.
912 * Returns: (transfer none): a pointer to the memory for the buffer.
915 gst_buffer_map (GstBuffer * buffer, gsize * size, gsize * maxsize,
921 gboolean write, writable;
923 g_return_val_if_fail (GST_IS_BUFFER (buffer), NULL);
925 write = (flags & GST_MAP_WRITE) != 0;
926 writable = gst_buffer_is_writable (buffer);
928 /* check if we can write when asked for write access */
929 if (G_UNLIKELY (write && !writable))
932 len = GST_BUFFER_MEM_LEN (buffer);
934 if (G_UNLIKELY (len == 0)) {
935 /* no memory, return immediately */
943 if (G_LIKELY (len == 1)) {
944 /* we can take the first one */
945 mem = GST_BUFFER_MEM_PTR (buffer, 0);
947 /* we need to span memory */
949 /* if we can write, we can change the memory with the spanned
951 mem = _span_memory (buffer, 0, -1, write);
952 _replace_memory (buffer, mem);
956 /* extract all data in new memory, FIXME slow!! */
957 bsize = gst_buffer_get_size (buffer);
959 data = g_malloc (bsize);
960 gst_buffer_extract (buffer, 0, data, bsize);
969 if (G_UNLIKELY (write && !GST_MEMORY_IS_WRITABLE (mem))) {
971 /* replace with a writable copy */
972 copy = gst_memory_copy (mem, 0, -1);
973 GST_BUFFER_MEM_PTR (buffer, 0) = copy;
974 gst_memory_unref (mem);
978 data = gst_memory_map (mem, size, maxsize, flags);
985 g_return_val_if_fail (gst_buffer_is_writable (buffer), NULL);
992 * @buffer: a #GstBuffer.
993 * @data: the previously mapped data
994 * @size: the size of @data, or -1
996 * Release the memory previously mapped with gst_buffer_map(). Pass -1 to size
997 * if no update is needed.
999 * Returns: #TRUE on success. #FALSE can be returned when the new size is larger
1000 * than the maxsize of the memory.
1003 gst_buffer_unmap (GstBuffer * buffer, gpointer data, gssize size)
1008 g_return_val_if_fail (GST_IS_BUFFER (buffer), FALSE);
1009 g_return_val_if_fail (size >= -1, FALSE);
1011 len = GST_BUFFER_MEM_LEN (buffer);
1013 if (G_LIKELY (len == 1)) {
1014 GstMemory *mem = GST_BUFFER_MEM_PTR (buffer, 0);
1016 result = gst_memory_unmap (mem, data, size);
1018 /* this must have been from read-only access. After _map, the buffer either
1019 * only contains 1 memory block or it allocated memory to join memory
1020 * blocks. It's not allowed to add buffers between _map and _unmap. */
1029 * @buffer: a #GstBuffer.
1030 * @offset: the offset to fill
1031 * @src: the source address
1032 * @size: the size to fill
1034 * Copy @size bytes from @src to @buffer at @offset.
1036 * Returns: The amount of bytes copied. This value can be lower than @size
1037 * when @buffer did not contain enough data.
1040 gst_buffer_fill (GstBuffer * buffer, gsize offset, gconstpointer src,
1044 const guint8 *ptr = src;
1046 g_return_val_if_fail (GST_IS_BUFFER (buffer), 0);
1047 g_return_val_if_fail (gst_buffer_is_writable (buffer), 0);
1048 g_return_val_if_fail (src != NULL, 0);
1050 len = GST_BUFFER_MEM_LEN (buffer);
1053 for (i = 0; i < len && left > 0; i++) {
1055 gsize ssize, tocopy;
1058 mem = _get_memory (buffer, i, TRUE);
1060 data = gst_memory_map (mem, &ssize, NULL, GST_MAP_WRITE);
1061 if (ssize > offset) {
1062 /* we have enough */
1063 tocopy = MIN (ssize - offset, left);
1064 memcpy (data + offset, ptr, tocopy);
1069 /* offset past buffer, skip */
1072 gst_memory_unmap (mem, data, ssize);
1078 * gst_buffer_extract:
1079 * @buffer: a #GstBuffer.
1080 * @offset: the offset to extract
1081 * @dest: the destination address
1082 * @size: the size to extract
1084 * Copy @size bytes starting from @offset in @buffer to @dest.
1086 * Returns: The amount of bytes extracted. This value can be lower than @size
1087 * when @buffer did not contain enough data.
1090 gst_buffer_extract (GstBuffer * buffer, gsize offset, gpointer dest, gsize size)
1095 g_return_val_if_fail (GST_IS_BUFFER (buffer), 0);
1096 g_return_val_if_fail (dest != NULL, 0);
1098 len = GST_BUFFER_MEM_LEN (buffer);
1101 for (i = 0; i < len && left > 0; i++) {
1103 gsize ssize, tocopy;
1106 mem = GST_BUFFER_MEM_PTR (buffer, i);
1108 data = gst_memory_map (mem, &ssize, NULL, GST_MAP_READ);
1109 if (ssize > offset) {
1110 /* we have enough */
1111 tocopy = MIN (ssize - offset, left);
1112 memcpy (ptr, data + offset, tocopy);
1117 /* offset past buffer, skip */
1120 gst_memory_unmap (mem, data, ssize);
1126 * gst_buffer_memcmp:
1127 * @buffer: a #GstBuffer.
1128 * @offset: the offset in @buffer
1129 * @mem: the memory to compare
1130 * @size: the size to compare
1132 * Compare @size bytes starting from @offset in @buffer with the memory in @mem.
1134 * Returns: 0 if the memory is equal.
1137 gst_buffer_memcmp (GstBuffer * buffer, gsize offset, gconstpointer mem,
1141 const guint8 *ptr = mem;
1144 g_return_val_if_fail (GST_IS_BUFFER (buffer), 0);
1145 g_return_val_if_fail (mem != NULL, 0);
1147 len = GST_BUFFER_MEM_LEN (buffer);
1149 for (i = 0; i < len && size > 0 && res == 0; i++) {
1154 mem = GST_BUFFER_MEM_PTR (buffer, i);
1156 data = gst_memory_map (mem, &ssize, NULL, GST_MAP_READ);
1157 if (ssize > offset) {
1158 /* we have enough */
1159 tocmp = MIN (ssize - offset, size);
1160 res = memcmp (ptr, data + offset, tocmp);
1165 /* offset past buffer, skip */
1168 gst_memory_unmap (mem, data, ssize);
1174 * gst_buffer_memset:
1175 * @buffer: a #GstBuffer.
1176 * @offset: the offset in @buffer
1177 * @val: the value to set
1178 * @size: the size to set
1180 * Fill @buf with @size bytes with @val starting from @offset.
1182 * Returns: The amount of bytes filled. This value can be lower than @size
1183 * when @buffer did not contain enough data.
1186 gst_buffer_memset (GstBuffer * buffer, gsize offset, guint8 val, gsize size)
1190 g_return_val_if_fail (GST_IS_BUFFER (buffer), 0);
1191 g_return_val_if_fail (gst_buffer_is_writable (buffer), 0);
1193 len = GST_BUFFER_MEM_LEN (buffer);
1196 for (i = 0; i < len && left > 0; i++) {
1201 mem = GST_BUFFER_MEM_PTR (buffer, i);
1203 data = gst_memory_map (mem, &ssize, NULL, GST_MAP_WRITE);
1204 if (ssize > offset) {
1205 /* we have enough */
1206 toset = MIN (ssize - offset, left);
1207 memset (data + offset, val, toset);
1211 /* offset past buffer, skip */
1214 gst_memory_unmap (mem, data, ssize);
1220 * gst_buffer_copy_region:
1221 * @parent: a #GstBuffer.
1222 * @flags: the #GstBufferCopyFlags
1223 * @offset: the offset into parent #GstBuffer at which the new sub-buffer
1225 * @size: the size of the new #GstBuffer sub-buffer, in bytes.
1227 * Creates a sub-buffer from @parent at @offset and @size.
1228 * This sub-buffer uses the actual memory space of the parent buffer.
1229 * This function will copy the offset and timestamp fields when the
1230 * offset is 0. If not, they will be set to #GST_CLOCK_TIME_NONE and
1231 * #GST_BUFFER_OFFSET_NONE.
1232 * If @offset equals 0 and @size equals the total size of @buffer, the
1233 * duration and offset end fields are also copied. If not they will be set
1234 * to #GST_CLOCK_TIME_NONE and #GST_BUFFER_OFFSET_NONE.
1238 * Returns: (transfer full): the new #GstBuffer or NULL if the arguments were
1242 gst_buffer_copy_region (GstBuffer * buffer, GstBufferCopyFlags flags,
1243 gsize offset, gsize size)
1247 g_return_val_if_fail (buffer != NULL, NULL);
1249 /* create the new buffer */
1250 copy = gst_buffer_new ();
1252 GST_CAT_LOG (GST_CAT_BUFFER, "new region copy %p of %p %" G_GSIZE_FORMAT
1253 "-%" G_GSIZE_FORMAT, copy, buffer, offset, size);
1255 gst_buffer_copy_into (copy, buffer, flags, offset, size);
1261 _gst_buffer_arr_is_span_fast (GstMemory ** mem[], gsize len[], guint n,
1262 gsize * offset, GstMemory ** parent)
1264 GstMemory *mcur, *mprv;
1265 gboolean have_offset = FALSE;
1269 for (count = 0; count < n; count++) {
1276 for (i = 0; i < clen; i++) {
1282 /* check is memory is contiguous */
1283 if (!gst_memory_is_span (mprv, mcur, &offs))
1290 *parent = mprv->parent;
1301 _gst_buffer_arr_span (GstMemory ** mem[], gsize len[], guint n, gsize offset,
1302 gsize size, gboolean writable)
1304 GstMemory *span, *parent = NULL;
1308 && _gst_buffer_arr_is_span_fast (mem, len, n, &poffset, &parent)) {
1309 if (parent->flags & GST_MEMORY_FLAG_NO_SHARE)
1310 span = gst_memory_copy (parent, offset + poffset, size);
1312 span = gst_memory_share (parent, offset + poffset, size);
1317 span = gst_allocator_alloc (NULL, size, 0);
1318 dest = gst_memory_map (span, NULL, NULL, GST_MAP_WRITE);
1323 for (count = 0; count < n; count++) {
1324 gsize i, tocopy, clen, ssize;
1331 for (i = 0; i < clen && left > 0; i++) {
1332 src = gst_memory_map (cmem[i], &ssize, NULL, GST_MAP_READ);
1333 tocopy = MIN (ssize, left);
1334 if (tocopy > offset) {
1335 memcpy (ptr, src + offset, tocopy - offset);
1342 gst_memory_unmap (cmem[i], src, ssize);
1345 gst_memory_unmap (span, dest, size);
1351 * gst_buffer_is_span_fast:
1352 * @buf1: the first #GstBuffer.
1353 * @buf2: the second #GstBuffer.
1355 * Determines whether a gst_buffer_span() can be done without copying
1356 * the contents, that is, whether the data areas are contiguous sub-buffers of
1360 * Returns: TRUE if the buffers are contiguous,
1361 * FALSE if a copy would be required.
1364 gst_buffer_is_span_fast (GstBuffer * buf1, GstBuffer * buf2)
1369 g_return_val_if_fail (GST_IS_BUFFER (buf1), FALSE);
1370 g_return_val_if_fail (GST_IS_BUFFER (buf2), FALSE);
1371 g_return_val_if_fail (buf1->mini_object.refcount > 0, FALSE);
1372 g_return_val_if_fail (buf2->mini_object.refcount > 0, FALSE);
1374 mem[0] = GST_BUFFER_MEM_ARRAY (buf1);
1375 len[0] = GST_BUFFER_MEM_LEN (buf1);
1376 mem[1] = GST_BUFFER_MEM_ARRAY (buf2);
1377 len[1] = GST_BUFFER_MEM_LEN (buf2);
1379 return _gst_buffer_arr_is_span_fast (mem, len, 2, NULL, NULL);
1384 * @buf1: the first source #GstBuffer to merge.
1385 * @offset: the offset in the first buffer from where the new
1386 * buffer should start.
1387 * @buf2: the second source #GstBuffer to merge.
1388 * @size: the total size of the new buffer.
1390 * Creates a new buffer that consists of part of buf1 and buf2.
1391 * Logically, buf1 and buf2 are concatenated into a single larger
1392 * buffer, and a new buffer is created at the given offset inside
1393 * this space, with a given length.
1395 * If the two source buffers are children of the same larger buffer,
1396 * and are contiguous, the new buffer will be a child of the shared
1397 * parent, and thus no copying is necessary. you can use
1398 * gst_buffer_is_span_fast() to determine if a memcpy will be needed.
1402 * Returns: (transfer full): the new #GstBuffer that spans the two source
1403 * buffers, or NULL if the arguments are invalid.
1406 gst_buffer_span (GstBuffer * buf1, gsize offset, GstBuffer * buf2, gsize size)
1411 gsize len[2], len1, len2;
1413 g_return_val_if_fail (GST_IS_BUFFER (buf1), NULL);
1414 g_return_val_if_fail (GST_IS_BUFFER (buf2), NULL);
1415 g_return_val_if_fail (buf1->mini_object.refcount > 0, NULL);
1416 g_return_val_if_fail (buf2->mini_object.refcount > 0, NULL);
1417 len1 = gst_buffer_get_size (buf1);
1418 len2 = gst_buffer_get_size (buf2);
1419 g_return_val_if_fail (len1 + len2 > offset, NULL);
1421 size = len1 + len2 - offset;
1423 g_return_val_if_fail (size <= len1 + len2 - offset, NULL);
1425 mem[0] = GST_BUFFER_MEM_ARRAY (buf1);
1426 len[0] = GST_BUFFER_MEM_LEN (buf1);
1427 mem[1] = GST_BUFFER_MEM_ARRAY (buf2);
1428 len[1] = GST_BUFFER_MEM_LEN (buf2);
1430 span = _gst_buffer_arr_span (mem, len, 2, offset, size, FALSE);
1432 newbuf = gst_buffer_new ();
1433 _memory_add (newbuf, -1, span);
1436 /* if the offset is 0, the new buffer has the same timestamp as buf1 */
1438 GST_BUFFER_OFFSET (newbuf) = GST_BUFFER_OFFSET (buf1);
1439 GST_BUFFER_PTS (newbuf) = GST_BUFFER_PTS (buf1);
1440 GST_BUFFER_DTS (newbuf) = GST_BUFFER_DTS (buf1);
1442 /* if we completely merged the two buffers (appended), we can
1443 * calculate the duration too. Also make sure we's not messing with
1444 * invalid DURATIONS */
1445 if (buf1->size + buf2->size == len) {
1446 if (GST_BUFFER_DURATION_IS_VALID (buf1) &&
1447 GST_BUFFER_DURATION_IS_VALID (buf2)) {
1449 GST_BUFFER_DURATION (newbuf) = GST_BUFFER_DURATION (buf1) +
1450 GST_BUFFER_DURATION (buf2);
1452 if (GST_BUFFER_OFFSET_END_IS_VALID (buf2)) {
1453 /* add offset_end */
1454 GST_BUFFER_OFFSET_END (newbuf) = GST_BUFFER_OFFSET_END (buf2);
1464 * gst_buffer_get_meta:
1465 * @buffer: a #GstBuffer
1466 * @info: a #GstMetaInfo
1468 * Get the metadata for the api in @info on buffer. When there is no such
1469 * metadata, NULL is returned.
1471 * Note that the result metadata might not be of the implementation @info.
1473 * Returns: the metadata for the api in @info on @buffer.
1476 gst_buffer_get_meta (GstBuffer * buffer, const GstMetaInfo * info)
1479 GstMeta *result = NULL;
1481 g_return_val_if_fail (buffer != NULL, NULL);
1482 g_return_val_if_fail (info != NULL, NULL);
1484 /* find GstMeta of the requested API */
1485 for (item = GST_BUFFER_META (buffer); item; item = item->next) {
1486 GstMeta *meta = &item->meta;
1487 if (meta->info->api == info->api) {
1496 * gst_buffer_add_meta:
1497 * @buffer: a #GstBuffer
1498 * @info: a #GstMetaInfo
1499 * @params: params for @info
1501 * Add metadata for @info to @buffer using the parameters in @params.
1503 * Returns: (transfer none): the metadata for the api in @info on @buffer.
1506 gst_buffer_add_meta (GstBuffer * buffer, const GstMetaInfo * info,
1510 GstMeta *result = NULL;
1513 g_return_val_if_fail (buffer != NULL, NULL);
1514 g_return_val_if_fail (info != NULL, NULL);
1516 /* create a new slice */
1517 GST_CAT_DEBUG (GST_CAT_BUFFER, "alloc metadata %s of size %" G_GSIZE_FORMAT,
1518 g_type_name (info->type), info->size);
1520 size = ITEM_SIZE (info);
1521 item = g_slice_alloc (size);
1522 result = &item->meta;
1523 result->info = info;
1525 /* call the init_func when needed */
1526 if (info->init_func)
1527 if (!info->init_func (result, params, buffer))
1530 /* and add to the list of metadata */
1531 item->next = GST_BUFFER_META (buffer);
1532 GST_BUFFER_META (buffer) = item;
1538 g_slice_free1 (size, item);
1544 * gst_buffer_remove_meta:
1545 * @buffer: a #GstBuffer
1548 * Remove the metadata for @meta on @buffer.
1550 * Returns: %TRUE if the metadata existed and was removed, %FALSE if no such
1551 * metadata was on @buffer.
1554 gst_buffer_remove_meta (GstBuffer * buffer, GstMeta * meta)
1556 GstMetaItem *walk, *prev;
1558 g_return_val_if_fail (buffer != NULL, FALSE);
1559 g_return_val_if_fail (meta != NULL, FALSE);
1561 /* find the metadata and delete */
1562 prev = GST_BUFFER_META (buffer);
1563 for (walk = prev; walk; walk = walk->next) {
1564 GstMeta *m = &walk->meta;
1566 const GstMetaInfo *info = meta->info;
1568 /* remove from list */
1569 if (GST_BUFFER_META (buffer) == walk)
1570 GST_BUFFER_META (buffer) = walk->next;
1572 prev->next = walk->next;
1573 /* call free_func if any */
1574 if (info->free_func)
1575 info->free_func (m, buffer);
1577 /* and free the slice */
1578 g_slice_free1 (ITEM_SIZE (info), walk);
1583 return walk != NULL;
1587 * gst_buffer_iterate_meta:
1588 * @buffer: a #GstBuffer
1589 * @state: an opaque state pointer
1591 * Retrieve the next #GstMeta after @current. If @state points
1592 * to %NULL, the first metadata is returned.
1594 * @state will be updated with an opage state pointer
1596 * Returns: The next #GstMeta or %NULL when there are no more items.
1599 gst_buffer_iterate_meta (GstBuffer * buffer, gpointer * state)
1603 g_return_val_if_fail (buffer != NULL, NULL);
1604 g_return_val_if_fail (state != NULL, NULL);
1606 meta = (GstMetaItem **) state;
1608 /* state NULL, move to first item */
1609 *meta = GST_BUFFER_META (buffer);
1611 /* state !NULL, move to next item in list */
1612 *meta = (*meta)->next;
1615 return &(*meta)->meta;