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
26 * @see_also: #GstPad, #GstMiniObject, #GstMemory, #GstMeta, #GstBufferPool
28 * Buffers are the basic unit of data transfer in GStreamer. They contain the
29 * timing and offset along with other arbitrary metadata that is associated
30 * with the #GstMemory blocks that the buffer contains.
32 * Buffers are usually created with gst_buffer_new(). After a buffer has been
33 * created one will typically allocate memory for it and add it to the buffer.
34 * The following example creates a buffer that can hold a given video frame
35 * with a given width, height and bits per plane.
37 * <title>Creating a buffer for a video frame</title>
41 * gint size, width, height, bpp;
43 * size = width * height * bpp;
44 * buffer = gst_buffer_new ();
45 * memory = gst_allocator_alloc (NULL, size, NULL);
46 * gst_buffer_insert_memory (buffer, -1, memory);
51 * Alternatively, use gst_buffer_new_allocate()
52 * to create a buffer with preallocated data of a given size.
54 * Buffers can contain a list of #GstMemory objects. You can retrieve how many
55 * memory objects with gst_buffer_n_memory() and you can get a pointer
56 * to memory with gst_buffer_peek_memory()
58 * A buffer will usually have timestamps, and a duration, but neither of these
59 * are guaranteed (they may be set to #GST_CLOCK_TIME_NONE). Whenever a
60 * meaningful value can be given for these, they should be set. The timestamps
61 * and duration are measured in nanoseconds (they are #GstClockTime values).
63 * The buffer DTS refers to the timestamp when the buffer should be decoded and
64 * is usually monotonically increasing. The buffer PTS refers to the timestamp when
65 * the buffer content should be presented to the user and is not always
66 * monotonically increasing.
68 * A buffer can also have one or both of a start and an end offset. These are
69 * media-type specific. For video buffers, the start offset will generally be
70 * the frame number. For audio buffers, it will be the number of samples
71 * produced so far. For compressed data, it could be the byte offset in a
72 * source or destination file. Likewise, the end offset will be the offset of
73 * the end of the buffer. These can only be meaningfully interpreted if you
74 * know the media type of the buffer (the preceeding CAPS event). Either or both
75 * can be set to #GST_BUFFER_OFFSET_NONE.
77 * gst_buffer_ref() is used to increase the refcount of a buffer. This must be
78 * done when you want to keep a handle to the buffer after pushing it to the
79 * next element. The buffer refcount determines the writability of the buffer, a
80 * buffer is only writable when the refcount is exactly 1, i.e. when the caller
81 * has the only reference to the buffer.
83 * To efficiently create a smaller buffer out of an existing one, you can
84 * use gst_buffer_copy_region(). This method tries to share the memory objects
85 * between the two buffers.
87 * If a plug-in wants to modify the buffer data or metadata in-place, it should
88 * first obtain a buffer that is safe to modify by using
89 * gst_buffer_make_writable(). This function is optimized so that a copy will
90 * only be made when it is necessary.
92 * Several flags of the buffer can be set and unset with the
93 * GST_BUFFER_FLAG_SET() and GST_BUFFER_FLAG_UNSET() macros. Use
94 * GST_BUFFER_FLAG_IS_SET() to test if a certain #GstBufferFlag is set.
96 * Buffers can be efficiently merged into a larger buffer with
97 * gst_buffer_append(). Copying of memory will only be done when absolutely
100 * Arbitrary extra metadata can be set on a buffer with gst_buffer_add_meta().
101 * Metadata can be retrieved with gst_buffer_get_meta(). See also #GstMeta
103 * An element should either unref the buffer or push it out on a src pad
104 * using gst_pad_push() (see #GstPad).
106 * Buffers are usually freed by unreffing them with gst_buffer_unref(). When
107 * the refcount drops to 0, any memory and metadata pointed to by the buffer is
108 * unreffed as well. Buffers allocated from a #GstBufferPool will be returned to
109 * the pool when the refcount drops to 0.
111 * Last reviewed on 2012-03-28 (0.11.3)
113 #include "gst_private.h"
122 #include "gstbuffer.h"
123 #include "gstbufferpool.h"
125 #include "gstutils.h"
126 #include "gstminiobject.h"
127 #include "gstversion.h"
129 GType _gst_buffer_type = 0;
131 typedef struct _GstMetaItem GstMetaItem;
138 #define ITEM_SIZE(info) ((info)->size + sizeof (GstMetaItem))
140 #define GST_BUFFER_MEM_MAX 16
142 #define GST_BUFFER_MEM_LEN(b) (((GstBufferImpl *)(b))->len)
143 #define GST_BUFFER_MEM_ARRAY(b) (((GstBufferImpl *)(b))->mem)
144 #define GST_BUFFER_MEM_PTR(b,i) (((GstBufferImpl *)(b))->mem[i])
145 #define GST_BUFFER_BUFMEM(b) (((GstBufferImpl *)(b))->bufmem)
146 #define GST_BUFFER_META(b) (((GstBufferImpl *)(b))->item)
152 /* the memory blocks */
154 GstMemory *mem[GST_BUFFER_MEM_MAX];
156 /* memory of the buffer when allocated from 1 chunk */
159 /* FIXME, make metadata allocation more efficient by using part of the
166 _is_span (GstMemory ** mem, gsize len, gsize * poffset, GstMemory ** parent)
168 GstMemory *mcur, *mprv;
169 gboolean have_offset = FALSE;
174 for (i = 0; i < len; i++) {
182 /* check if memory is contiguous */
183 if (!gst_memory_is_span (mprv, mcur, &poffs))
190 *parent = mprv->parent;
200 _get_merged_memory (GstBuffer * buffer, guint idx, guint length)
202 GstMemory **mem, *result;
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_size (buffer);
216 if (G_UNLIKELY (_is_span (mem + idx, length, &poffset, &parent))) {
218 if (parent->flags & GST_MEMORY_FLAG_NO_SHARE) {
219 GST_CAT_DEBUG (GST_CAT_PERFORMANCE, "copy for merge %p", parent);
220 result = gst_memory_copy (parent, poffset, size);
222 result = gst_memory_share (parent, poffset, size);
225 gsize i, tocopy, left;
226 GstMapInfo sinfo, dinfo;
229 result = gst_allocator_alloc (NULL, size, NULL);
230 gst_memory_map (result, &dinfo, GST_MAP_WRITE);
235 for (i = idx; i < length && left > 0; i++) {
236 gst_memory_map (mem[i], &sinfo, GST_MAP_READ);
237 tocopy = MIN (sinfo.size, left);
238 GST_CAT_DEBUG (GST_CAT_PERFORMANCE,
239 "memcpy for merge %p from memory %p", 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,
258 GST_LOG ("buffer %p replace %u-%" G_GSIZE_FORMAT " with memory %p", buffer,
261 /* unref old memory */
262 for (i = idx; i < end; i++)
263 gst_memory_unref (GST_BUFFER_MEM_PTR (buffer, i));
266 /* replace with single memory */
267 GST_BUFFER_MEM_PTR (buffer, idx) = mem;
273 g_memmove (&GST_BUFFER_MEM_PTR (buffer, idx),
274 &GST_BUFFER_MEM_PTR (buffer, end), (len - end) * sizeof (gpointer));
276 GST_BUFFER_MEM_LEN (buffer) = len - length;
280 _memory_add (GstBuffer * buffer, guint idx, GstMemory * mem)
282 guint i, len = GST_BUFFER_MEM_LEN (buffer);
284 if (G_UNLIKELY (len >= GST_BUFFER_MEM_MAX)) {
285 /* too many buffer, span them. */
286 /* FIXME, there is room for improvement here: We could only try to merge
287 * 2 buffers to make some room. If we can't efficiently merge 2 buffers we
288 * could try to only merge the two smallest buffers to avoid memcpy, etc. */
289 GST_CAT_DEBUG (GST_CAT_PERFORMANCE, "memory array overflow in buffer %p",
291 _replace_memory (buffer, len, 0, len, _get_merged_memory (buffer, 0, len));
292 /* we now have 1 single spanned buffer */
299 for (i = len; i > idx; i--) {
300 /* move buffers to insert, FIXME, we need to insert first and then merge */
301 GST_BUFFER_MEM_PTR (buffer, i) = GST_BUFFER_MEM_PTR (buffer, i - 1);
303 /* and insert the new buffer */
304 GST_BUFFER_MEM_PTR (buffer, idx) = mem;
305 GST_BUFFER_MEM_LEN (buffer) = len + 1;
308 GST_DEFINE_MINI_OBJECT_TYPE (GstBuffer, gst_buffer);
311 _priv_gst_buffer_initialize (void)
313 _gst_buffer_type = gst_buffer_get_type ();
317 * gst_buffer_copy_into:
318 * @dest: a destination #GstBuffer
319 * @src: a source #GstBuffer
320 * @flags: flags indicating what metadata fields should be copied.
321 * @offset: offset to copy from
322 * @size: total size to copy. If -1, all data is copied.
324 * Copies the information from @src into @dest.
326 * If @dest already contains memory and @flags contains GST_BUFFER_COPY_MEMORY,
327 * the memory from @src will be appended to @dest.
329 * @flags indicate which fields will be copied.
332 gst_buffer_copy_into (GstBuffer * dest, GstBuffer * src,
333 GstBufferCopyFlags flags, gsize offset, gsize size)
337 gboolean region = FALSE;
339 g_return_if_fail (dest != NULL);
340 g_return_if_fail (src != NULL);
342 /* nothing to copy if the buffers are the same */
343 if (G_UNLIKELY (dest == src))
346 g_return_if_fail (gst_buffer_is_writable (dest));
348 bufsize = gst_buffer_get_size (src);
349 g_return_if_fail (bufsize >= offset);
353 size = bufsize - offset;
356 g_return_if_fail (bufsize >= offset + size);
358 GST_CAT_LOG (GST_CAT_BUFFER, "copy %p to %p, offset %" G_GSIZE_FORMAT
359 "-%" G_GSIZE_FORMAT "/%" G_GSIZE_FORMAT, src, dest, offset, size,
362 if (flags & GST_BUFFER_COPY_FLAGS) {
364 GST_MINI_OBJECT_FLAGS (dest) = GST_MINI_OBJECT_FLAGS (src);
367 if (flags & GST_BUFFER_COPY_TIMESTAMPS) {
369 GST_BUFFER_PTS (dest) = GST_BUFFER_PTS (src);
370 GST_BUFFER_DTS (dest) = GST_BUFFER_DTS (src);
371 GST_BUFFER_OFFSET (dest) = GST_BUFFER_OFFSET (src);
372 if (size == bufsize) {
373 GST_BUFFER_DURATION (dest) = GST_BUFFER_DURATION (src);
374 GST_BUFFER_OFFSET_END (dest) = GST_BUFFER_OFFSET_END (src);
377 GST_BUFFER_PTS (dest) = GST_CLOCK_TIME_NONE;
378 GST_BUFFER_DTS (dest) = GST_CLOCK_TIME_NONE;
379 GST_BUFFER_DURATION (dest) = GST_CLOCK_TIME_NONE;
380 GST_BUFFER_OFFSET (dest) = GST_BUFFER_OFFSET_NONE;
381 GST_BUFFER_OFFSET_END (dest) = GST_BUFFER_OFFSET_NONE;
385 if (flags & GST_BUFFER_COPY_MEMORY) {
387 gsize skip, left, len, i, bsize;
389 len = GST_BUFFER_MEM_LEN (src);
393 /* copy and make regions of the memory */
394 for (i = 0; i < len && left > 0; i++) {
395 mem = GST_BUFFER_MEM_PTR (src, i);
396 bsize = gst_memory_get_sizes (mem, NULL, NULL);
399 /* don't copy buffer */
404 tocopy = MIN (bsize - skip, left);
405 if (mem->flags & GST_MEMORY_FLAG_NO_SHARE) {
406 /* no share, always copy then */
407 mem = gst_memory_copy (mem, skip, tocopy);
409 } else if (tocopy < bsize) {
410 /* we need to clip something */
411 mem = gst_memory_share (mem, skip, tocopy);
414 mem = gst_memory_ref (mem);
416 _memory_add (dest, -1, mem);
420 if (flags & GST_BUFFER_COPY_MERGE) {
421 len = GST_BUFFER_MEM_LEN (dest);
422 _replace_memory (dest, len, 0, len, _get_merged_memory (dest, 0, len));
426 if (flags & GST_BUFFER_COPY_META) {
427 for (walk = GST_BUFFER_META (src); walk; walk = walk->next) {
428 GstMeta *meta = &walk->meta;
429 const GstMetaInfo *info = meta->info;
431 if (info->transform_func) {
432 GstMetaTransformCopy copy_data;
434 copy_data.region = region;
435 copy_data.offset = offset;
436 copy_data.size = size;
438 info->transform_func (dest, meta, src,
439 _gst_meta_transform_copy, ©_data);
446 _gst_buffer_copy (GstBuffer * buffer)
450 g_return_val_if_fail (buffer != NULL, NULL);
452 /* create a fresh new buffer */
453 copy = gst_buffer_new ();
455 /* we simply copy everything from our parent */
456 gst_buffer_copy_into (copy, buffer, GST_BUFFER_COPY_ALL, 0, -1);
461 /* the default dispose function revives the buffer and returns it to the
462 * pool when there is a pool */
464 _gst_buffer_dispose (GstBuffer * buffer)
468 /* no pool, do free */
469 if ((pool = buffer->pool) == NULL)
472 /* keep the buffer alive */
473 gst_buffer_ref (buffer);
474 /* return the buffer to the pool */
475 GST_CAT_LOG (GST_CAT_BUFFER, "release %p to pool %p", buffer, pool);
476 gst_buffer_pool_release_buffer (pool, buffer);
482 _gst_buffer_free (GstBuffer * buffer)
484 GstMetaItem *walk, *next;
488 g_return_if_fail (buffer != NULL);
490 GST_CAT_LOG (GST_CAT_BUFFER, "finalize %p", buffer);
493 for (walk = GST_BUFFER_META (buffer); walk; walk = next) {
494 GstMeta *meta = &walk->meta;
495 const GstMetaInfo *info = meta->info;
497 /* call free_func if any */
499 info->free_func (meta, buffer);
502 /* and free the slice */
503 g_slice_free1 (ITEM_SIZE (info), walk);
506 /* get the size, when unreffing the memory, we could also unref the buffer
508 msize = GST_MINI_OBJECT_SIZE (buffer);
510 /* free our memory */
511 len = GST_BUFFER_MEM_LEN (buffer);
512 for (i = 0; i < len; i++)
513 gst_memory_unref (GST_BUFFER_MEM_PTR (buffer, i));
515 /* we set msize to 0 when the buffer is part of the memory block */
517 g_slice_free1 (msize, buffer);
519 gst_memory_unref (GST_BUFFER_BUFMEM (buffer));
523 gst_buffer_init (GstBufferImpl * buffer, gsize size)
525 gst_mini_object_init (GST_MINI_OBJECT_CAST (buffer), _gst_buffer_type, size);
527 buffer->buffer.mini_object.copy =
528 (GstMiniObjectCopyFunction) _gst_buffer_copy;
529 buffer->buffer.mini_object.dispose =
530 (GstMiniObjectDisposeFunction) _gst_buffer_dispose;
531 buffer->buffer.mini_object.free =
532 (GstMiniObjectFreeFunction) _gst_buffer_free;
534 GST_BUFFER (buffer)->pool = NULL;
535 GST_BUFFER_PTS (buffer) = GST_CLOCK_TIME_NONE;
536 GST_BUFFER_DTS (buffer) = GST_CLOCK_TIME_NONE;
537 GST_BUFFER_DURATION (buffer) = GST_CLOCK_TIME_NONE;
538 GST_BUFFER_OFFSET (buffer) = GST_BUFFER_OFFSET_NONE;
539 GST_BUFFER_OFFSET_END (buffer) = GST_BUFFER_OFFSET_NONE;
541 GST_BUFFER_MEM_LEN (buffer) = 0;
542 GST_BUFFER_META (buffer) = NULL;
548 * Creates a newly allocated buffer without any data.
552 * Returns: (transfer full): the new #GstBuffer.
555 gst_buffer_new (void)
557 GstBufferImpl *newbuf;
559 newbuf = g_slice_new (GstBufferImpl);
560 GST_CAT_LOG (GST_CAT_BUFFER, "new %p", newbuf);
562 gst_buffer_init (newbuf, sizeof (GstBufferImpl));
564 return GST_BUFFER_CAST (newbuf);
568 * gst_buffer_new_allocate:
569 * @allocator: (transfer none) (allow-none): the #GstAllocator to use, or NULL to use the
571 * @size: the size in bytes of the new buffer's data.
572 * @params: (transfer none) (allow-none): optional parameters
574 * Tries to create a newly allocated buffer with data of the given size and
575 * extra parameters from @allocator. If the requested amount of memory can't be
576 * allocated, NULL will be returned. The allocated buffer memory is not cleared.
578 * When @allocator is NULL, the default memory allocator will be used.
580 * Note that when @size == 0, the buffer will not have memory associated with it.
584 * Returns: (transfer full): a new #GstBuffer, or NULL if the memory couldn't
588 gst_buffer_new_allocate (GstAllocator * allocator, gsize size,
589 GstAllocationParams * params)
600 mem = gst_allocator_alloc (allocator, size, params);
601 if (G_UNLIKELY (mem == NULL))
607 newbuf = gst_buffer_new ();
610 _memory_add (newbuf, -1, mem);
612 GST_CAT_LOG (GST_CAT_BUFFER,
613 "new buffer %p of size %" G_GSIZE_FORMAT " from allocator %p", newbuf,
618 asize = sizeof (GstBufferImpl) + size;
619 data = g_slice_alloc (asize);
620 if (G_UNLIKELY (data == NULL))
623 newbuf = GST_BUFFER_CAST (data);
625 gst_buffer_init ((GstBufferImpl *) data, asize);
627 mem = gst_memory_new_wrapped (0, data + sizeof (GstBufferImpl), NULL,
629 _memory_add (newbuf, -1, mem);
634 /* allocate memory and buffer, it might be interesting to do this but there
635 * are many complications. We need to keep the memory mapped to access the
636 * buffer fields and the memory for the buffer might be just very slow. We
637 * also need to do some more magic to get the alignment right. */
638 asize = sizeof (GstBufferImpl) + size;
639 mem = gst_allocator_alloc (allocator, asize, align);
640 if (G_UNLIKELY (mem == NULL))
643 /* map the data part and init the buffer in it, set the buffer size to 0 so
644 * that a finalize won't free the buffer */
645 data = gst_memory_map (mem, &asize, NULL, GST_MAP_WRITE);
646 gst_buffer_init ((GstBufferImpl *) data, 0);
647 gst_memory_unmap (mem);
649 /* strip off the buffer */
650 gst_memory_resize (mem, sizeof (GstBufferImpl), size);
652 newbuf = GST_BUFFER_CAST (data);
653 GST_BUFFER_BUFMEM (newbuf) = mem;
656 _memory_add (newbuf, -1, gst_memory_ref (mem));
664 GST_CAT_WARNING (GST_CAT_BUFFER,
665 "failed to allocate %" G_GSIZE_FORMAT " bytes", size);
671 * gst_buffer_new_wrapped_full:
672 * @flags: #GstMemoryFlags
673 * @data: data to wrap
674 * @maxsize: allocated size of @data
675 * @offset: offset in @data
676 * @size: size of valid data
677 * @user_data: user_data
678 * @notify: called with @user_data when the memory is freed
680 * Allocate a new buffer that wraps the given memory. @data must point to
681 * @maxsize of memory, the wrapped buffer will have the region from @offset and
684 * When the buffer is destroyed, @notify will be called with @user_data.
686 * The prefix/padding must be filled with 0 if @flags contains
687 * #GST_MEMORY_FLAG_ZERO_PREFIXED and #GST_MEMORY_FLAG_ZERO_PADDED respectively.
689 * Returns: (transfer full): a new #GstBuffer
692 gst_buffer_new_wrapped_full (GstMemoryFlags flags, gpointer data,
693 gsize maxsize, gsize offset, gsize size, gpointer user_data,
694 GDestroyNotify notify)
698 newbuf = gst_buffer_new ();
699 gst_buffer_append_memory (newbuf,
700 gst_memory_new_wrapped (flags, data, maxsize, offset, size,
707 * gst_buffer_new_wrapped:
708 * @data: data to wrap
709 * @size: allocated size of @data
711 * Creates a new buffer that wraps the given @data. The memory will be freed
712 * with g_free and will be marked writable.
716 * Returns: (transfer full): a new #GstBuffer
719 gst_buffer_new_wrapped (gpointer data, gsize size)
721 return gst_buffer_new_wrapped_full (0, data, size, 0, size, data, g_free);
725 * gst_buffer_n_memory:
726 * @buffer: a #GstBuffer.
728 * Get the amount of memory blocks that this buffer has.
730 * Returns: (transfer full): the amount of memory block in this buffer.
733 gst_buffer_n_memory (GstBuffer * buffer)
735 g_return_val_if_fail (GST_IS_BUFFER (buffer), 0);
737 return GST_BUFFER_MEM_LEN (buffer);
741 * gst_buffer_insert_memory:
742 * @buffer: a #GstBuffer.
743 * @idx: the index to add the memory at, or -1 to append it to the end
744 * @mem: (transfer full): a #GstMemory.
746 * Insert the memory block @mem to @buffer at @idx. This function takes ownership
747 * of @mem and thus doesn't increase its refcount.
750 gst_buffer_insert_memory (GstBuffer * buffer, gint idx, GstMemory * mem)
752 g_return_if_fail (GST_IS_BUFFER (buffer));
753 g_return_if_fail (gst_buffer_is_writable (buffer));
754 g_return_if_fail (mem != NULL);
755 g_return_if_fail (idx == -1 ||
756 (idx >= 0 && idx <= GST_BUFFER_MEM_LEN (buffer)));
758 _memory_add (buffer, idx, mem);
762 _get_mapped (GstBuffer * buffer, guint idx, GstMapInfo * info,
765 GstMemory *mem, *mapped;
767 mem = GST_BUFFER_MEM_PTR (buffer, idx);
769 mapped = gst_memory_make_mapped (mem, info, flags);
774 GST_BUFFER_MEM_PTR (buffer, idx) = mapped;
775 gst_memory_unref (mem);
782 * gst_buffer_peek_memory:
783 * @buffer: a #GstBuffer.
786 * Get the memory block at @idx in @buffer. The memory block stays valid until
787 * the memory block in @buffer is removed, replaced or merged, typically with
788 * any call that modifies the memory in @buffer.
790 * Since this call does not influence the refcount of the memory,
791 * gst_memory_is_exclusive() can be used to check if @buffer is the sole owner
792 * of the returned memory.
794 * Returns: (transfer none): the #GstMemory at @idx.
797 gst_buffer_peek_memory (GstBuffer * buffer, guint idx)
801 g_return_val_if_fail (GST_IS_BUFFER (buffer), NULL);
802 len = GST_BUFFER_MEM_LEN (buffer);
803 g_return_val_if_fail (idx < len, NULL);
805 return GST_BUFFER_MEM_PTR (buffer, idx);
809 * gst_buffer_get_memory_range:
810 * @buffer: a #GstBuffer.
814 * Get @length memory blocks in @buffer starting at @idx. The memory blocks will
815 * be merged into one large #GstMemory.
817 * If @length is -1, all memory starting from @idx is merged.
819 * Returns: (transfer full): a #GstMemory that contains the merged data of @length
820 * blocks starting at @idx. Use gst_memory_unref () after usage.
823 gst_buffer_get_memory_range (GstBuffer * buffer, guint idx, gint length)
827 GST_DEBUG ("idx %u, length %d", idx, length);
829 g_return_val_if_fail (GST_IS_BUFFER (buffer), NULL);
830 len = GST_BUFFER_MEM_LEN (buffer);
831 g_return_val_if_fail ((length == -1 && idx < len) ||
832 (length > 0 && length + idx <= len), NULL);
837 return _get_merged_memory (buffer, idx, length);
841 * gst_buffer_replace_memory_range:
842 * @buffer: a #GstBuffer.
844 * @length: a length should not be 0
845 * @mem: (transfer full): a #GstMemory
847 * Replaces @length memory blocks in @buffer starting at @idx with @mem.
849 * If @length is -1, all memory starting from @idx will be removed and
850 * replaced with @mem.
852 * @buffer should be writable.
855 gst_buffer_replace_memory_range (GstBuffer * buffer, guint idx, gint length,
860 g_return_if_fail (GST_IS_BUFFER (buffer));
861 g_return_if_fail (gst_buffer_is_writable (buffer));
862 len = GST_BUFFER_MEM_LEN (buffer);
863 g_return_if_fail ((length == -1 && idx < len) || (length > 0
864 && length + idx <= len));
869 _replace_memory (buffer, len, idx, length, mem);
873 * gst_buffer_remove_memory_range:
874 * @buffer: a #GstBuffer.
878 * Remove @length memory blocks in @buffer starting from @idx.
880 * @length can be -1, in which case all memory starting from @idx is removed.
883 gst_buffer_remove_memory_range (GstBuffer * buffer, guint idx, gint length)
887 g_return_if_fail (GST_IS_BUFFER (buffer));
888 g_return_if_fail (gst_buffer_is_writable (buffer));
890 len = GST_BUFFER_MEM_LEN (buffer);
891 g_return_if_fail ((length == -1 && idx < len) || length + idx <= len);
896 _replace_memory (buffer, len, idx, length, NULL);
900 * gst_buffer_find_memory:
901 * @buffer: a #GstBuffer.
904 * @idx: (out): pointer to index
905 * @length: (out): pointer to length
906 * @skip: (out): pointer to skip
908 * Find the memory blocks that span @size bytes starting from @offset
911 * When this function returns %TRUE, @idx will contain the index of the first
912 * memory bock where the byte for @offset can be found and @length contains the
913 * number of memory blocks containing the @size remaining bytes. @skip contains
914 * the number of bytes to skip in the memory bock at @idx to get to the byte
917 * @size can be -1 to get all the memory blocks after @idx.
919 * Returns: %TRUE when @size bytes starting from @offset could be found in
920 * @buffer and @idx, @length and @skip will be filled.
923 gst_buffer_find_memory (GstBuffer * buffer, gsize offset, gsize size,
924 guint * idx, guint * length, gsize * skip)
928 g_return_val_if_fail (GST_IS_BUFFER (buffer), FALSE);
929 g_return_val_if_fail (idx != NULL, FALSE);
930 g_return_val_if_fail (length != NULL, FALSE);
931 g_return_val_if_fail (skip != NULL, FALSE);
933 len = GST_BUFFER_MEM_LEN (buffer);
936 for (i = 0; i < len; i++) {
940 mem = GST_BUFFER_MEM_PTR (buffer, i);
941 s = gst_memory_get_sizes (mem, NULL, NULL);
944 /* block before offset, or empty block, skip */
947 /* block after offset */
949 /* first block, remember index and offset */
953 /* return remaining blocks */
960 /* count the amount of found bytes */
963 /* we have enough bytes */
964 *length = i - *idx + 1;
973 * gst_buffer_get_sizes_range:
974 * @buffer: a #GstBuffer.
977 * @offset: a pointer to the offset
978 * @maxsize: a pointer to the maxsize
980 * Get the total size of @length memory blocks stating from @idx in @buffer.
982 * When not %NULL, @offset will contain the offset of the data in the
983 * memory block in @buffer at @idx and @maxsize will contain the sum of the size
984 * and @offset and the amount of extra padding on the memory block at @idx +
986 * @offset and @maxsize can be used to resize the buffer memory blocks with
987 * gst_buffer_resize_range().
989 * Returns: total size @length memory blocks starting at @idx in @buffer.
992 gst_buffer_get_sizes_range (GstBuffer * buffer, guint idx, gint length,
993 gsize * offset, gsize * maxsize)
999 g_return_val_if_fail (GST_IS_BUFFER (buffer), 0);
1000 len = GST_BUFFER_MEM_LEN (buffer);
1001 g_return_val_if_fail (len == 0 || (length == -1 && idx < len)
1002 || (length + idx <= len), 0);
1007 if (G_LIKELY (length == 1)) {
1009 mem = GST_BUFFER_MEM_PTR (buffer, idx);
1010 size = gst_memory_get_sizes (mem, offset, maxsize);
1016 size = offs = extra = 0;
1017 for (i = idx; i < end; i++) {
1020 mem = GST_BUFFER_MEM_PTR (buffer, i);
1021 s = gst_memory_get_sizes (mem, &o, &ms);
1025 /* first size, take accumulated data before as the offset */
1029 /* save the amount of data after this block */
1030 extra = ms - (o + s);
1032 /* empty block, add as extra */
1039 *maxsize = offs + size + extra;
1045 * gst_buffer_resize_range:
1046 * @buffer: a #GstBuffer.
1049 * @offset: the offset adjustement
1050 * @size: the new size or -1 to just adjust the offset
1052 * Set the total size of the @length memory blocks starting at @idx in
1056 gst_buffer_resize_range (GstBuffer * buffer, guint idx, gint length,
1057 gssize offset, gssize size)
1060 gsize bsize, bufsize, bufoffs, bufmax;
1063 g_return_if_fail (gst_buffer_is_writable (buffer));
1064 g_return_if_fail (size >= -1);
1065 len = GST_BUFFER_MEM_LEN (buffer);
1066 g_return_if_fail ((length == -1 && idx < len) || (length + idx <= len));
1071 bufsize = gst_buffer_get_sizes_range (buffer, idx, length, &bufoffs, &bufmax);
1073 GST_CAT_LOG (GST_CAT_BUFFER, "trim %p %" G_GSSIZE_FORMAT "-%" G_GSSIZE_FORMAT
1074 " size:%" G_GSIZE_FORMAT " offs:%" G_GSIZE_FORMAT " max:%"
1075 G_GSIZE_FORMAT, buffer, offset, size, bufsize, bufoffs, bufmax);
1077 /* we can't go back further than the current offset or past the end of the
1079 g_return_if_fail ((offset < 0 && bufoffs >= -offset) || (offset >= 0
1080 && bufoffs + offset <= bufmax));
1082 g_return_if_fail (bufsize >= offset);
1083 size = bufsize - offset;
1085 g_return_if_fail (bufmax >= bufoffs + offset + size);
1088 if (offset == 0 && size == bufsize)
1093 for (i = idx; i < end; i++) {
1096 mem = GST_BUFFER_MEM_PTR (buffer, i);
1097 bsize = gst_memory_get_sizes (mem, NULL, NULL);
1100 /* last buffer always gets resized to the remaining size */
1103 /* shrink buffers before the offset */
1104 else if ((gssize) bsize <= offset) {
1106 noffs = offset - bsize;
1109 /* clip other buffers */
1111 left = MIN (bsize - offset, size);
1113 if (offset != 0 || left != bsize) {
1114 if (gst_memory_is_exclusive (mem)) {
1115 gst_memory_resize (mem, offset, left);
1119 if (mem->flags & GST_MEMORY_FLAG_NO_SHARE)
1120 tmp = gst_memory_copy (mem, offset, left);
1122 tmp = gst_memory_share (mem, offset, left);
1124 gst_memory_unref (mem);
1131 GST_BUFFER_MEM_PTR (buffer, i) = mem;
1136 * gst_buffer_map_range:
1137 * @buffer: a #GstBuffer.
1140 * @info: (out): info about the mapping
1141 * @flags: flags for the mapping
1143 * This function fills @info with the #GstMapInfo of @length merged memory blocks
1144 * starting at @idx in @buffer. When @length is -1, all memory blocks starting
1145 * from @idx are merged and mapped.
1146 * @flags describe the desired access of the memory. When @flags is
1147 * #GST_MAP_WRITE, @buffer should be writable (as returned from
1148 * gst_buffer_is_writable()).
1150 * When @buffer is writable but the memory isn't, a writable copy will
1151 * automatically be created and returned. The readonly copy of the buffer memory
1152 * will then also be replaced with this writable copy.
1154 * The memory in @info should be unmapped with gst_buffer_unmap() after usage.
1156 * Returns: (transfer full): %TRUE if the map succeeded and @info contains valid
1160 gst_buffer_map_range (GstBuffer * buffer, guint idx, gint length,
1161 GstMapInfo * info, GstMapFlags flags)
1163 GstMemory *mem, *nmem;
1164 gboolean write, writable;
1167 g_return_val_if_fail (GST_IS_BUFFER (buffer), FALSE);
1168 g_return_val_if_fail (info != NULL, FALSE);
1169 len = GST_BUFFER_MEM_LEN (buffer);
1172 g_return_val_if_fail ((length == -1 && idx < len) || (length > 0
1173 && length + idx <= len), FALSE);
1175 write = (flags & GST_MAP_WRITE) != 0;
1176 writable = gst_buffer_is_writable (buffer);
1178 /* check if we can write when asked for write access */
1179 if (G_UNLIKELY (write && !writable))
1185 mem = _get_merged_memory (buffer, idx, length);
1186 if (G_UNLIKELY (mem == NULL))
1189 /* now try to map */
1190 nmem = gst_memory_make_mapped (mem, info, flags);
1191 if (G_UNLIKELY (nmem == NULL))
1194 /* if we merged or when the map returned a different memory, we try to replace
1195 * the memory in the buffer */
1196 if (G_UNLIKELY (length > 1 || nmem != mem)) {
1197 /* if the buffer is writable, replace the memory */
1199 _replace_memory (buffer, len, idx, length, gst_memory_ref (nmem));
1202 GST_CAT_DEBUG (GST_CAT_PERFORMANCE,
1203 "temporary mapping for memory %p in buffer %p", nmem, buffer);
1212 GST_WARNING_OBJECT (buffer, "write map requested on non-writable buffer");
1213 g_critical ("write map requested on non-writable buffer");
1218 /* empty buffer, we need to return NULL */
1219 GST_DEBUG_OBJECT (buffer, "can't get buffer memory");
1220 info->memory = NULL;
1228 GST_DEBUG_OBJECT (buffer, "cannot map memory");
1235 * @buffer: a #GstBuffer.
1236 * @info: a #GstMapInfo
1238 * Release the memory previously mapped with gst_buffer_map().
1241 gst_buffer_unmap (GstBuffer * buffer, GstMapInfo * info)
1243 g_return_if_fail (GST_IS_BUFFER (buffer));
1244 g_return_if_fail (info != NULL);
1246 /* we need to check for NULL, it is possible that we tried to map a buffer
1247 * without memory and we should be able to unmap that fine */
1248 if (G_LIKELY (info->memory)) {
1249 gst_memory_unmap (info->memory, info);
1250 gst_memory_unref (info->memory);
1256 * @buffer: a #GstBuffer.
1257 * @offset: the offset to fill
1258 * @src: the source address
1259 * @size: the size to fill
1261 * Copy @size bytes from @src to @buffer at @offset.
1263 * Returns: The amount of bytes copied. This value can be lower than @size
1264 * when @buffer did not contain enough data.
1267 gst_buffer_fill (GstBuffer * buffer, gsize offset, gconstpointer src,
1271 const guint8 *ptr = src;
1273 g_return_val_if_fail (GST_IS_BUFFER (buffer), 0);
1274 g_return_val_if_fail (gst_buffer_is_writable (buffer), 0);
1275 g_return_val_if_fail (src != NULL, 0);
1277 len = GST_BUFFER_MEM_LEN (buffer);
1280 for (i = 0; i < len && left > 0; i++) {
1285 mem = _get_mapped (buffer, i, &info, GST_MAP_WRITE);
1286 if (info.size > offset) {
1287 /* we have enough */
1288 tocopy = MIN (info.size - offset, left);
1289 memcpy ((guint8 *) info.data + offset, ptr, tocopy);
1294 /* offset past buffer, skip */
1295 offset -= info.size;
1297 gst_memory_unmap (mem, &info);
1303 * gst_buffer_extract:
1304 * @buffer: a #GstBuffer.
1305 * @offset: the offset to extract
1306 * @dest: the destination address
1307 * @size: the size to extract
1309 * Copy @size bytes starting from @offset in @buffer to @dest.
1311 * Returns: The amount of bytes extracted. This value can be lower than @size
1312 * when @buffer did not contain enough data.
1315 gst_buffer_extract (GstBuffer * buffer, gsize offset, gpointer dest, gsize size)
1320 g_return_val_if_fail (GST_IS_BUFFER (buffer), 0);
1321 g_return_val_if_fail (dest != NULL, 0);
1323 len = GST_BUFFER_MEM_LEN (buffer);
1326 for (i = 0; i < len && left > 0; i++) {
1331 mem = _get_mapped (buffer, i, &info, GST_MAP_READ);
1332 if (info.size > offset) {
1333 /* we have enough */
1334 tocopy = MIN (info.size - offset, left);
1335 memcpy (ptr, (guint8 *) info.data + offset, tocopy);
1340 /* offset past buffer, skip */
1341 offset -= info.size;
1343 gst_memory_unmap (mem, &info);
1349 * gst_buffer_memcmp:
1350 * @buffer: a #GstBuffer.
1351 * @offset: the offset in @buffer
1352 * @mem: the memory to compare
1353 * @size: the size to compare
1355 * Compare @size bytes starting from @offset in @buffer with the memory in @mem.
1357 * Returns: 0 if the memory is equal.
1360 gst_buffer_memcmp (GstBuffer * buffer, gsize offset, gconstpointer mem,
1364 const guint8 *ptr = mem;
1367 g_return_val_if_fail (GST_IS_BUFFER (buffer), 0);
1368 g_return_val_if_fail (mem != NULL, 0);
1370 len = GST_BUFFER_MEM_LEN (buffer);
1372 for (i = 0; i < len && size > 0 && res == 0; i++) {
1377 mem = _get_mapped (buffer, i, &info, GST_MAP_READ);
1378 if (info.size > offset) {
1379 /* we have enough */
1380 tocmp = MIN (info.size - offset, size);
1381 res = memcmp (ptr, (guint8 *) info.data + offset, tocmp);
1386 /* offset past buffer, skip */
1387 offset -= info.size;
1389 gst_memory_unmap (mem, &info);
1395 * gst_buffer_memset:
1396 * @buffer: a #GstBuffer.
1397 * @offset: the offset in @buffer
1398 * @val: the value to set
1399 * @size: the size to set
1401 * Fill @buf with @size bytes with @val starting from @offset.
1403 * Returns: The amount of bytes filled. This value can be lower than @size
1404 * when @buffer did not contain enough data.
1407 gst_buffer_memset (GstBuffer * buffer, gsize offset, guint8 val, gsize size)
1411 g_return_val_if_fail (GST_IS_BUFFER (buffer), 0);
1412 g_return_val_if_fail (gst_buffer_is_writable (buffer), 0);
1414 len = GST_BUFFER_MEM_LEN (buffer);
1417 for (i = 0; i < len && left > 0; i++) {
1422 mem = _get_mapped (buffer, i, &info, GST_MAP_WRITE);
1423 if (info.size > offset) {
1424 /* we have enough */
1425 toset = MIN (info.size - offset, left);
1426 memset ((guint8 *) info.data + offset, val, toset);
1430 /* offset past buffer, skip */
1431 offset -= info.size;
1433 gst_memory_unmap (mem, &info);
1439 * gst_buffer_copy_region:
1440 * @parent: a #GstBuffer.
1441 * @flags: the #GstBufferCopyFlags
1442 * @offset: the offset into parent #GstBuffer at which the new sub-buffer
1444 * @size: the size of the new #GstBuffer sub-buffer, in bytes.
1446 * Creates a sub-buffer from @parent at @offset and @size.
1447 * This sub-buffer uses the actual memory space of the parent buffer.
1448 * This function will copy the offset and timestamp fields when the
1449 * offset is 0. If not, they will be set to #GST_CLOCK_TIME_NONE and
1450 * #GST_BUFFER_OFFSET_NONE.
1451 * If @offset equals 0 and @size equals the total size of @buffer, the
1452 * duration and offset end fields are also copied. If not they will be set
1453 * to #GST_CLOCK_TIME_NONE and #GST_BUFFER_OFFSET_NONE.
1457 * Returns: (transfer full): the new #GstBuffer or NULL if the arguments were
1461 gst_buffer_copy_region (GstBuffer * buffer, GstBufferCopyFlags flags,
1462 gsize offset, gsize size)
1466 g_return_val_if_fail (buffer != NULL, NULL);
1468 /* create the new buffer */
1469 copy = gst_buffer_new ();
1471 GST_CAT_LOG (GST_CAT_BUFFER, "new region copy %p of %p %" G_GSIZE_FORMAT
1472 "-%" G_GSIZE_FORMAT, copy, buffer, offset, size);
1474 gst_buffer_copy_into (copy, buffer, flags, offset, size);
1480 * gst_buffer_append:
1481 * @buf1: (transfer full): the first source #GstBuffer to append.
1482 * @buf2: (transfer full): the second source #GstBuffer to append.
1484 * Append all the memory from @buf2 to @buf1. The result buffer will contain a
1485 * concatenation of the memory of @buf1 and @buf2.
1487 * Returns: (transfer full): the new #GstBuffer that contains the memory
1488 * of the two source buffers.
1491 gst_buffer_append (GstBuffer * buf1, GstBuffer * buf2)
1495 g_return_val_if_fail (GST_IS_BUFFER (buf1), NULL);
1496 g_return_val_if_fail (GST_IS_BUFFER (buf2), NULL);
1498 buf1 = gst_buffer_make_writable (buf1);
1499 buf2 = gst_buffer_make_writable (buf2);
1501 len = GST_BUFFER_MEM_LEN (buf2);
1502 for (i = 0; i < len; i++) {
1505 mem = GST_BUFFER_MEM_PTR (buf2, i);
1506 GST_BUFFER_MEM_PTR (buf2, i) = NULL;
1507 _memory_add (buf1, -1, mem);
1510 /* we can calculate the duration too. Also make sure we're not messing
1511 * with invalid DURATIONS */
1512 if (GST_BUFFER_DURATION_IS_VALID (buf1) &&
1513 GST_BUFFER_DURATION_IS_VALID (buf2)) {
1515 GST_BUFFER_DURATION (buf1) += GST_BUFFER_DURATION (buf2);
1517 if (GST_BUFFER_OFFSET_END_IS_VALID (buf2)) {
1518 /* set offset_end */
1519 GST_BUFFER_OFFSET_END (buf1) = GST_BUFFER_OFFSET_END (buf2);
1522 GST_BUFFER_MEM_LEN (buf2) = 0;
1523 gst_buffer_unref (buf2);
1529 * gst_buffer_get_meta:
1530 * @buffer: a #GstBuffer
1531 * @api: the #GType of an API
1533 * Get the metadata for @api on buffer. When there is no such
1534 * metadata, NULL is returned.
1536 * Returns: the metadata for @api on @buffer.
1539 gst_buffer_get_meta (GstBuffer * buffer, GType api)
1542 GstMeta *result = NULL;
1544 g_return_val_if_fail (buffer != NULL, NULL);
1545 g_return_val_if_fail (api != 0, NULL);
1547 /* find GstMeta of the requested API */
1548 for (item = GST_BUFFER_META (buffer); item; item = item->next) {
1549 GstMeta *meta = &item->meta;
1550 if (meta->info->api == api) {
1559 * gst_buffer_add_meta:
1560 * @buffer: a #GstBuffer
1561 * @info: a #GstMetaInfo
1562 * @params: params for @info
1564 * Add metadata for @info to @buffer using the parameters in @params.
1566 * Returns: (transfer none): the metadata for the api in @info on @buffer.
1569 gst_buffer_add_meta (GstBuffer * buffer, const GstMetaInfo * info,
1573 GstMeta *result = NULL;
1576 g_return_val_if_fail (buffer != NULL, NULL);
1577 g_return_val_if_fail (info != NULL, NULL);
1578 g_return_val_if_fail (gst_buffer_is_writable (buffer), NULL);
1580 /* create a new slice */
1581 size = ITEM_SIZE (info);
1582 item = g_slice_alloc (size);
1583 result = &item->meta;
1584 result->info = info;
1585 result->flags = GST_META_FLAG_NONE;
1587 GST_CAT_DEBUG (GST_CAT_BUFFER,
1588 "alloc metadata %p (%s) of size %" G_GSIZE_FORMAT, result,
1589 g_type_name (info->type), info->size);
1591 /* call the init_func when needed */
1592 if (info->init_func)
1593 if (!info->init_func (result, params, buffer))
1596 /* and add to the list of metadata */
1597 item->next = GST_BUFFER_META (buffer);
1598 GST_BUFFER_META (buffer) = item;
1604 g_slice_free1 (size, item);
1610 * gst_buffer_remove_meta:
1611 * @buffer: a #GstBuffer
1614 * Remove the metadata for @meta on @buffer.
1616 * Returns: %TRUE if the metadata existed and was removed, %FALSE if no such
1617 * metadata was on @buffer.
1620 gst_buffer_remove_meta (GstBuffer * buffer, GstMeta * meta)
1622 GstMetaItem *walk, *prev;
1624 g_return_val_if_fail (buffer != NULL, FALSE);
1625 g_return_val_if_fail (meta != NULL, FALSE);
1626 g_return_val_if_fail (gst_buffer_is_writable (buffer), FALSE);
1628 /* find the metadata and delete */
1629 prev = GST_BUFFER_META (buffer);
1630 for (walk = prev; walk; walk = walk->next) {
1631 GstMeta *m = &walk->meta;
1633 const GstMetaInfo *info = meta->info;
1635 /* remove from list */
1636 if (GST_BUFFER_META (buffer) == walk)
1637 GST_BUFFER_META (buffer) = walk->next;
1639 prev->next = walk->next;
1640 /* call free_func if any */
1641 if (info->free_func)
1642 info->free_func (m, buffer);
1644 /* and free the slice */
1645 g_slice_free1 (ITEM_SIZE (info), walk);
1650 return walk != NULL;
1654 * gst_buffer_iterate_meta:
1655 * @buffer: a #GstBuffer
1656 * @state: an opaque state pointer
1658 * Retrieve the next #GstMeta after @current. If @state points
1659 * to %NULL, the first metadata is returned.
1661 * @state will be updated with an opage state pointer
1663 * Returns: The next #GstMeta or %NULL when there are no more items.
1666 gst_buffer_iterate_meta (GstBuffer * buffer, gpointer * state)
1670 g_return_val_if_fail (buffer != NULL, NULL);
1671 g_return_val_if_fail (state != NULL, NULL);
1673 meta = (GstMetaItem **) state;
1675 /* state NULL, move to first item */
1676 *meta = GST_BUFFER_META (buffer);
1678 /* state !NULL, move to next item in list */
1679 *meta = (*meta)->next;
1682 return &(*meta)->meta;
1688 * gst_buffer_foreach_meta:
1689 * @buffer: a #GstBuffer
1690 * @func: (scope call): a #GstBufferForeachMetaFunc to call
1691 * @user_data: (closure): user data passed to @func
1693 * Call @func with @user_data for each meta in @buffer.
1695 * @func can modify the passed meta pointer or its contents. The return value
1696 * of @func define if this function returns or if the remaining metadata items
1697 * in the buffer should be skipped.
1700 gst_buffer_foreach_meta (GstBuffer * buffer, GstBufferForeachMetaFunc func,
1703 GstMetaItem *walk, *prev, *next;
1705 g_return_if_fail (buffer != NULL);
1706 g_return_if_fail (func != NULL);
1708 /* find the metadata and delete */
1709 prev = GST_BUFFER_META (buffer);
1710 for (walk = prev; walk; walk = next) {
1714 m = new = &walk->meta;
1717 res = func (buffer, &new, user_data);
1720 const GstMetaInfo *info = m->info;
1722 GST_CAT_DEBUG (GST_CAT_BUFFER, "remove metadata %p (%s)", m,
1723 g_type_name (info->type));
1725 g_return_if_fail (gst_buffer_is_writable (buffer));
1727 /* remove from list */
1728 if (GST_BUFFER_META (buffer) == walk)
1729 GST_BUFFER_META (buffer) = next;
1733 /* call free_func if any */
1734 if (info->free_func)
1735 info->free_func (m, buffer);
1737 /* and free the slice */
1738 g_slice_free1 (ITEM_SIZE (info), walk);