gstreamer/subprojects/gstreamer/gst/gstbuffer.c
Sebastian Dröge 128dd3d82c buffer: Don't copy reference timestamp meta if the destination buffer already has the same
GstRtpBaseDepayload and other places already had such de-duplication code, so
it's probably better to solve this at the root.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/7747>
2024-10-28 12:35:57 +00:00

3113 lines
87 KiB
C

/* GStreamer
* Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
* 2000 Wim Taymans <wtay@chello.be>
*
* gstbuffer.c: Buffer operations
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
* Boston, MA 02110-1301, USA.
*/
/**
* SECTION:gstbuffer
* @title: GstBuffer
* @short_description: Data-passing buffer type
* @see_also: #GstPad, #GstMiniObject, #GstMemory, #GstMeta, #GstBufferPool
*
* Buffers are the basic unit of data transfer in GStreamer. They contain the
* timing and offset along with other arbitrary metadata that is associated
* with the #GstMemory blocks that the buffer contains.
*
* Buffers are usually created with gst_buffer_new(). After a buffer has been
* created one will typically allocate memory for it and add it to the buffer.
* The following example creates a buffer that can hold a given video frame
* with a given width, height and bits per plane.
*
* ``` C
* GstBuffer *buffer;
* GstMemory *memory;
* gint size, width, height, bpp;
* ...
* size = width * height * bpp;
* buffer = gst_buffer_new ();
* memory = gst_allocator_alloc (NULL, size, NULL);
* gst_buffer_insert_memory (buffer, -1, memory);
* ...
* ```
*
* Alternatively, use gst_buffer_new_allocate() to create a buffer with
* preallocated data of a given size.
*
* Buffers can contain a list of #GstMemory objects. You can retrieve how many
* memory objects with gst_buffer_n_memory() and you can get a pointer
* to memory with gst_buffer_peek_memory()
*
* A buffer will usually have timestamps, and a duration, but neither of these
* are guaranteed (they may be set to #GST_CLOCK_TIME_NONE). Whenever a
* meaningful value can be given for these, they should be set. The timestamps
* and duration are measured in nanoseconds (they are #GstClockTime values).
*
* The buffer DTS refers to the timestamp when the buffer should be decoded and
* is usually monotonically increasing. The buffer PTS refers to the timestamp when
* the buffer content should be presented to the user and is not always
* monotonically increasing.
*
* A buffer can also have one or both of a start and an end offset. These are
* media-type specific. For video buffers, the start offset will generally be
* the frame number. For audio buffers, it will be the number of samples
* produced so far. For compressed data, it could be the byte offset in a
* source or destination file. Likewise, the end offset will be the offset of
* the end of the buffer. These can only be meaningfully interpreted if you
* know the media type of the buffer (the preceding CAPS event). Either or both
* can be set to #GST_BUFFER_OFFSET_NONE.
*
* gst_buffer_ref() is used to increase the refcount of a buffer. This must be
* done when you want to keep a handle to the buffer after pushing it to the
* next element. The buffer refcount determines the writability of the buffer, a
* buffer is only writable when the refcount is exactly 1, i.e. when the caller
* has the only reference to the buffer.
*
* To efficiently create a smaller buffer out of an existing one, you can
* use gst_buffer_copy_region(). This method tries to share the memory objects
* between the two buffers.
*
* If a plug-in wants to modify the buffer data or metadata in-place, it should
* first obtain a buffer that is safe to modify by using
* gst_buffer_make_writable(). This function is optimized so that a copy will
* only be made when it is necessary.
*
* Several flags of the buffer can be set and unset with the
* GST_BUFFER_FLAG_SET() and GST_BUFFER_FLAG_UNSET() macros. Use
* GST_BUFFER_FLAG_IS_SET() to test if a certain #GstBufferFlags flag is set.
*
* Buffers can be efficiently merged into a larger buffer with
* gst_buffer_append(). Copying of memory will only be done when absolutely
* needed.
*
* Arbitrary extra metadata can be set on a buffer with gst_buffer_add_meta().
* Metadata can be retrieved with gst_buffer_get_meta(). See also #GstMeta.
*
* An element should either unref the buffer or push it out on a src pad
* using gst_pad_push() (see #GstPad).
*
* Buffers are usually freed by unreffing them with gst_buffer_unref(). When
* the refcount drops to 0, any memory and metadata pointed to by the buffer is
* unreffed as well. Buffers allocated from a #GstBufferPool will be returned to
* the pool when the refcount drops to 0.
*
* The #GstParentBufferMeta is a meta which can be attached to a #GstBuffer
* to hold a reference to another buffer that is only released when the child
* #GstBuffer is released.
*
* Typically, #GstParentBufferMeta is used when the child buffer is directly
* using the #GstMemory of the parent buffer, and wants to prevent the parent
* buffer from being returned to a buffer pool until the #GstMemory is available
* for re-use. (Since: 1.6)
*/
#define GST_DISABLE_MINIOBJECT_INLINE_FUNCTIONS
#include "gst_private.h"
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#ifdef HAVE_STDLIB_H
#include <stdlib.h>
#endif
#include "gstbuffer.h"
#include "gstbufferpool.h"
#include "gstinfo.h"
#include "gstmeta.h"
#include "gstutils.h"
#include "gstversion.h"
/* For g_memdup2 */
#include "glib-compat-private.h"
GType _gst_buffer_type = 0;
/* info->size will be sizeof(FooMeta) which contains a GstMeta at the beginning
* too, and then there is again a GstMeta in GstMetaItem, so subtract one. */
#define ITEM_SIZE(info) ((info)->size + sizeof (GstMetaItem) - sizeof (GstMeta))
#define GST_BUFFER_MEM_MAX 16
#define GST_BUFFER_MEM_LEN(b) (((GstBufferImpl *)(b))->len)
#define GST_BUFFER_MEM_ARRAY(b) (((GstBufferImpl *)(b))->mem)
#define GST_BUFFER_MEM_PTR(b,i) (((GstBufferImpl *)(b))->mem[i])
#define GST_BUFFER_BUFMEM(b) (((GstBufferImpl *)(b))->bufmem)
#define GST_BUFFER_META(b) (((GstBufferImpl *)(b))->item)
#define GST_BUFFER_TAIL_META(b) (((GstBufferImpl *)(b))->tail_item)
typedef struct
{
GstBuffer buffer;
/* the memory blocks */
guint len;
GstMemory *mem[GST_BUFFER_MEM_MAX];
/* memory of the buffer when allocated from 1 chunk */
GstMemory *bufmem;
/* FIXME, make metadata allocation more efficient by using part of the
* GstBufferImpl */
GstMetaItem *item;
GstMetaItem *tail_item;
} GstBufferImpl;
static gint64 meta_seq; /* 0 *//* ATOMIC */
/* TODO: use GLib's once https://gitlab.gnome.org/GNOME/glib/issues/1076 lands */
#if defined(__STDC_VERSION__) && __STDC_VERSION__ >= 201112L && !defined(__STDC_NO_ATOMICS__)
#include <stdatomic.h>
static inline gint64
gst_atomic_int64_inc (gint64 * atomic)
{
return atomic_fetch_add ((_Atomic gint64 *) atomic, 1);
}
#elif defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_8)
static inline gint64
gst_atomic_int64_inc (gint64 * atomic)
{
return __sync_fetch_and_add (atomic, 1);
}
#elif defined (G_PLATFORM_WIN32)
#include <windows.h>
static inline gint64
gst_atomic_int64_inc (gint64 * atomic)
{
return InterlockedExchangeAdd64 (atomic, 1);
}
#else
#define STR_TOKEN(s) #s
#define STR(s) STR_TOKEN(s)
#pragma message "No 64-bit atomic int defined for this " STR(TARGET_CPU) " platform/toolchain!"
#define NO_64BIT_ATOMIC_INT_FOR_PLATFORM
G_LOCK_DEFINE_STATIC (meta_seq);
static inline gint64
gst_atomic_int64_inc (gint64 * atomic)
{
gint64 ret;
G_LOCK (meta_seq);
ret = (*atomic)++;
G_UNLOCK (meta_seq);
return ret;
}
#endif
static gboolean
_is_span (GstMemory ** mem, gsize len, gsize * poffset, GstMemory ** parent)
{
GstMemory *mcur, *mprv;
gboolean have_offset = FALSE;
gsize i;
mcur = mprv = NULL;
for (i = 0; i < len; i++) {
if (mcur)
mprv = mcur;
mcur = mem[i];
if (mprv && mcur) {
gsize poffs;
/* check if memory is contiguous */
if (!gst_memory_is_span (mprv, mcur, &poffs))
return FALSE;
if (!have_offset) {
if (poffset)
*poffset = poffs;
if (parent)
*parent = mprv->parent;
have_offset = TRUE;
}
}
}
return have_offset;
}
static GstMemory *
_actual_merged_memory (GstBuffer * buffer, guint idx, guint length)
{
GstMemory **mem, *result = NULL;
GstMemory *parent = NULL;
gsize size, poffset = 0;
mem = GST_BUFFER_MEM_ARRAY (buffer);
size = gst_buffer_get_sizes_range (buffer, idx, length, NULL, NULL);
if (G_UNLIKELY (_is_span (mem + idx, length, &poffset, &parent))) {
if (!GST_MEMORY_IS_NO_SHARE (parent))
result = gst_memory_share (parent, poffset, size);
if (!result) {
GST_CAT_DEBUG (GST_CAT_PERFORMANCE, "copy for merge %p", parent);
result = gst_memory_copy (parent, poffset, size);
}
} else {
gsize i, tocopy, left;
GstMapInfo sinfo, dinfo;
guint8 *ptr;
result = gst_allocator_alloc (NULL, size, NULL);
if (result == NULL || !gst_memory_map (result, &dinfo, GST_MAP_WRITE)) {
GST_CAT_ERROR (GST_CAT_BUFFER, "Failed to map memory writable");
if (result)
gst_memory_unref (result);
return NULL;
}
ptr = dinfo.data;
left = size;
for (i = idx; i < (idx + length) && left > 0; i++) {
if (!gst_memory_map (mem[i], &sinfo, GST_MAP_READ)) {
GST_CAT_ERROR (GST_CAT_BUFFER,
"buffer %p, idx %u, length %u failed to map readable", buffer,
idx, length);
gst_memory_unmap (result, &dinfo);
gst_memory_unref (result);
return NULL;
}
tocopy = MIN (sinfo.size, left);
GST_CAT_DEBUG (GST_CAT_PERFORMANCE,
"memcpy %" G_GSIZE_FORMAT " bytes for merge %p from memory %p",
tocopy, result, mem[i]);
memcpy (ptr, (guint8 *) sinfo.data, tocopy);
left -= tocopy;
ptr += tocopy;
gst_memory_unmap (mem[i], &sinfo);
}
gst_memory_unmap (result, &dinfo);
}
return result;
}
static inline GstMemory *
_get_merged_memory (GstBuffer * buffer, guint idx, guint length)
{
GST_CAT_LOG (GST_CAT_BUFFER, "buffer %p, idx %u, length %u", buffer, idx,
length);
if (G_UNLIKELY (length == 0))
return NULL;
if (G_LIKELY (length == 1))
return gst_memory_ref (GST_BUFFER_MEM_PTR (buffer, idx));
return _actual_merged_memory (buffer, idx, length);
}
static void
_replace_memory (GstBuffer * buffer, guint len, guint idx, guint length,
GstMemory * mem)
{
gsize end, i;
end = idx + length;
GST_CAT_LOG (GST_CAT_BUFFER,
"buffer %p replace %u-%" G_GSIZE_FORMAT " with memory %p", buffer, idx,
end, mem);
/* unref old memory */
for (i = idx; i < end; i++) {
GstMemory *old = GST_BUFFER_MEM_PTR (buffer, i);
gst_memory_unlock (old, GST_LOCK_FLAG_EXCLUSIVE);
gst_mini_object_remove_parent (GST_MINI_OBJECT_CAST (old),
GST_MINI_OBJECT_CAST (buffer));
gst_memory_unref (old);
}
if (mem != NULL) {
/* replace with single memory */
gst_mini_object_add_parent (GST_MINI_OBJECT_CAST (mem),
GST_MINI_OBJECT_CAST (buffer));
gst_memory_lock (mem, GST_LOCK_FLAG_EXCLUSIVE);
GST_BUFFER_MEM_PTR (buffer, idx) = mem;
idx++;
length--;
}
if (end < len) {
memmove (&GST_BUFFER_MEM_PTR (buffer, idx),
&GST_BUFFER_MEM_PTR (buffer, end), (len - end) * sizeof (gpointer));
}
GST_BUFFER_MEM_LEN (buffer) = len - length;
GST_BUFFER_FLAG_SET (buffer, GST_BUFFER_FLAG_TAG_MEMORY);
}
/**
* gst_buffer_get_flags:
* @buffer: a #GstBuffer
*
* Gets the #GstBufferFlags flags set on this buffer.
*
* Returns: the flags set on this buffer.
*
* Since: 1.10
*/
GstBufferFlags
gst_buffer_get_flags (GstBuffer * buffer)
{
return (GstBufferFlags) GST_BUFFER_FLAGS (buffer);
}
/**
* gst_buffer_has_flags:
* @buffer: a #GstBuffer
* @flags: the #GstBufferFlags flag to check.
*
* Gives the status of a specific flag on a buffer.
*
* Returns: %TRUE if all flags in @flags are found on @buffer.
*
* Since: 1.10
*/
gboolean
gst_buffer_has_flags (GstBuffer * buffer, GstBufferFlags flags)
{
return GST_BUFFER_FLAG_IS_SET (buffer, flags);
}
/**
* gst_buffer_set_flags:
* @buffer: a #GstBuffer
* @flags: the #GstBufferFlags to set.
*
* Sets one or more buffer flags on a buffer.
*
* Returns: %TRUE if @flags were successfully set on buffer.
*
* Since: 1.10
*/
gboolean
gst_buffer_set_flags (GstBuffer * buffer, GstBufferFlags flags)
{
GST_BUFFER_FLAG_SET (buffer, flags);
return TRUE;
}
/**
* gst_buffer_unset_flags:
* @buffer: a #GstBuffer
* @flags: the #GstBufferFlags to clear
*
* Clears one or more buffer flags.
*
* Returns: true if @flags is successfully cleared from buffer.
*
* Since: 1.10
*/
gboolean
gst_buffer_unset_flags (GstBuffer * buffer, GstBufferFlags flags)
{
GST_BUFFER_FLAG_UNSET (buffer, flags);
return TRUE;
}
/* transfer full for return and transfer none for @mem */
static inline GstMemory *
_memory_get_exclusive_reference (GstMemory * mem)
{
GstMemory *ret = NULL;
if (gst_memory_lock (mem, GST_LOCK_FLAG_EXCLUSIVE)) {
ret = gst_memory_ref (mem);
} else {
/* we cannot take another exclusive lock as the memory is already
* locked WRITE + EXCLUSIVE according to part-miniobject.txt */
ret = gst_memory_copy (mem, 0, -1);
if (ret) {
if (!gst_memory_lock (ret, GST_LOCK_FLAG_EXCLUSIVE)) {
gst_memory_unref (ret);
ret = NULL;
}
}
}
if (!ret)
GST_CAT_WARNING (GST_CAT_BUFFER, "Failed to acquire an exclusive lock for "
"memory %p", mem);
return ret;
}
static inline void
_memory_add (GstBuffer * buffer, gint idx, GstMemory * mem)
{
guint i, len = GST_BUFFER_MEM_LEN (buffer);
GST_CAT_LOG (GST_CAT_BUFFER, "buffer %p, idx %d, mem %p", buffer, idx, mem);
if (G_UNLIKELY (len >= GST_BUFFER_MEM_MAX)) {
/* too many buffer, span them. */
/* FIXME, there is room for improvement here: We could only try to merge
* 2 buffers to make some room. If we can't efficiently merge 2 buffers we
* could try to only merge the two smallest buffers to avoid memcpy, etc. */
GST_CAT_DEBUG (GST_CAT_PERFORMANCE, "memory array overflow in buffer %p",
buffer);
_replace_memory (buffer, len, 0, len, _get_merged_memory (buffer, 0, len));
/* we now have 1 single spanned buffer */
len = 1;
}
if (idx == -1)
idx = len;
for (i = len; i > idx; i--) {
/* move buffers to insert, FIXME, we need to insert first and then merge */
GST_BUFFER_MEM_PTR (buffer, i) = GST_BUFFER_MEM_PTR (buffer, i - 1);
}
/* and insert the new buffer */
GST_BUFFER_MEM_PTR (buffer, idx) = mem;
GST_BUFFER_MEM_LEN (buffer) = len + 1;
gst_mini_object_add_parent (GST_MINI_OBJECT_CAST (mem),
GST_MINI_OBJECT_CAST (buffer));
GST_BUFFER_FLAG_SET (buffer, GST_BUFFER_FLAG_TAG_MEMORY);
}
GST_DEFINE_MINI_OBJECT_TYPE (GstBuffer, gst_buffer);
void
_priv_gst_buffer_initialize (void)
{
_gst_buffer_type = gst_buffer_get_type ();
#ifdef NO_64BIT_ATOMIC_INT_FOR_PLATFORM
GST_CAT_WARNING (GST_CAT_PERFORMANCE,
"No 64-bit atomic int defined for this platform/toolchain!");
#endif
}
/**
* gst_buffer_get_max_memory:
*
* Gets the maximum amount of memory blocks that a buffer can hold. This is a
* compile time constant that can be queried with the function.
*
* When more memory blocks are added, existing memory blocks will be merged
* together to make room for the new block.
*
* Returns: the maximum amount of memory blocks that a buffer can hold.
*
* Since: 1.2
*/
guint
gst_buffer_get_max_memory (void)
{
return GST_BUFFER_MEM_MAX;
}
/**
* gst_buffer_copy_into:
* @dest: a destination #GstBuffer
* @src: a source #GstBuffer
* @flags: flags indicating what metadata fields should be copied.
* @offset: offset to copy from
* @size: total size to copy. If -1, all data is copied.
*
* Copies the information from @src into @dest.
*
* If @dest already contains memory and @flags contains GST_BUFFER_COPY_MEMORY,
* the memory from @src will be appended to @dest.
*
* @flags indicate which fields will be copied.
*
* Returns: %TRUE if the copying succeeded, %FALSE otherwise.
*/
gboolean
gst_buffer_copy_into (GstBuffer * dest, GstBuffer * src,
GstBufferCopyFlags flags, gsize offset, gsize size)
{
GstMetaItem *walk;
gsize bufsize;
gboolean region = FALSE;
gboolean sharing_mem = FALSE;
g_return_val_if_fail (dest != NULL, FALSE);
g_return_val_if_fail (src != NULL, FALSE);
/* nothing to copy if the buffers are the same */
if (G_UNLIKELY (dest == src))
return TRUE;
g_return_val_if_fail (gst_buffer_is_writable (dest), FALSE);
bufsize = gst_buffer_get_size (src);
g_return_val_if_fail (bufsize >= offset, FALSE);
if (offset > 0)
region = TRUE;
if (size == -1)
size = bufsize - offset;
if (size < bufsize)
region = TRUE;
g_return_val_if_fail (bufsize >= offset + size, FALSE);
GST_CAT_LOG (GST_CAT_BUFFER, "copy %p to %p, offset %" G_GSIZE_FORMAT
"-%" G_GSIZE_FORMAT "/%" G_GSIZE_FORMAT, src, dest, offset, size,
bufsize);
if (flags & GST_BUFFER_COPY_FLAGS) {
/* copy flags */
guint flags_mask = ~GST_BUFFER_FLAG_TAG_MEMORY;
GST_MINI_OBJECT_FLAGS (dest) =
(GST_MINI_OBJECT_FLAGS (src) & flags_mask) |
(GST_MINI_OBJECT_FLAGS (dest) & ~flags_mask);
}
if (flags & GST_BUFFER_COPY_TIMESTAMPS) {
if (offset == 0) {
GST_BUFFER_PTS (dest) = GST_BUFFER_PTS (src);
GST_BUFFER_DTS (dest) = GST_BUFFER_DTS (src);
GST_BUFFER_OFFSET (dest) = GST_BUFFER_OFFSET (src);
if (size == bufsize) {
GST_BUFFER_DURATION (dest) = GST_BUFFER_DURATION (src);
GST_BUFFER_OFFSET_END (dest) = GST_BUFFER_OFFSET_END (src);
}
} else {
GST_BUFFER_PTS (dest) = GST_CLOCK_TIME_NONE;
GST_BUFFER_DTS (dest) = GST_CLOCK_TIME_NONE;
GST_BUFFER_DURATION (dest) = GST_CLOCK_TIME_NONE;
GST_BUFFER_OFFSET (dest) = GST_BUFFER_OFFSET_NONE;
GST_BUFFER_OFFSET_END (dest) = GST_BUFFER_OFFSET_NONE;
}
}
if (flags & GST_BUFFER_COPY_MEMORY) {
gsize skip, left, len, dest_len, i, bsize;
gboolean deep;
deep = flags & GST_BUFFER_COPY_DEEP;
len = GST_BUFFER_MEM_LEN (src);
dest_len = GST_BUFFER_MEM_LEN (dest);
left = size;
skip = offset;
/* copy and make regions of the memory */
for (i = 0; i < len && left > 0; i++) {
GstMemory *mem = GST_BUFFER_MEM_PTR (src, i);
bsize = mem->size;
if (bsize <= skip) {
/* don't copy buffer */
skip -= bsize;
} else {
GstMemory *newmem = NULL;
gsize tocopy;
tocopy = MIN (bsize - skip, left);
if (tocopy < bsize && !deep && !GST_MEMORY_IS_NO_SHARE (mem)) {
/* we need to clip something */
newmem = gst_memory_share (mem, skip, tocopy);
if (newmem) {
gst_memory_lock (newmem, GST_LOCK_FLAG_EXCLUSIVE);
skip = 0;
}
}
if (deep || GST_MEMORY_IS_NO_SHARE (mem) || (!newmem && tocopy < bsize)) {
/* deep copy or we're not allowed to share this memory
* between buffers, always copy then */
newmem = gst_memory_copy (mem, skip, tocopy);
if (newmem) {
gst_memory_lock (newmem, GST_LOCK_FLAG_EXCLUSIVE);
skip = 0;
}
} else if (!newmem) {
newmem = _memory_get_exclusive_reference (mem);
}
if (!newmem) {
gst_buffer_remove_memory_range (dest, dest_len, -1);
return FALSE;
}
/* Indicates if dest references any of src memories. */
sharing_mem |= (newmem == mem);
_memory_add (dest, -1, newmem);
left -= tocopy;
}
}
if (flags & GST_BUFFER_COPY_MERGE) {
GstMemory *mem;
len = GST_BUFFER_MEM_LEN (dest);
mem = _get_merged_memory (dest, 0, len);
if (!mem) {
gst_buffer_remove_memory_range (dest, dest_len, -1);
return FALSE;
}
/* If we were sharing memory and the merge is no-op, we are still sharing. */
sharing_mem &= (mem == GST_BUFFER_MEM_PTR (dest, 0));
_replace_memory (dest, len, 0, len, mem);
}
}
if (flags & GST_BUFFER_COPY_META) {
gboolean deep;
deep = (flags & GST_BUFFER_COPY_DEEP) != 0;
/* NOTE: GstGLSyncMeta copying relies on the meta
* being copied now, after the buffer data,
* so this has to happen last */
for (walk = GST_BUFFER_META (src); walk; walk = walk->next) {
GstMeta *meta = &walk->meta;
const GstMetaInfo *info = meta->info;
/* Don't copy memory metas if we only copied part of the buffer, didn't
* copy memories or merged memories. In all these cases the memory
* structure has changed and the memory meta becomes meaningless.
*/
if ((region || !(flags & GST_BUFFER_COPY_MEMORY)
|| (flags & GST_BUFFER_COPY_MERGE))
&& gst_meta_api_type_has_tag (info->api, _gst_meta_tag_memory)) {
GST_CAT_DEBUG (GST_CAT_BUFFER,
"don't copy memory meta %p of API type %s", meta,
g_type_name (info->api));
} else if (deep && gst_meta_api_type_has_tag (info->api,
_gst_meta_tag_memory_reference)) {
GST_CAT_DEBUG (GST_CAT_BUFFER,
"don't copy memory reference meta %p of API type %s", meta,
g_type_name (info->api));
} else if (info->transform_func) {
GstMetaTransformCopy copy_data;
copy_data.region = region;
copy_data.offset = offset;
copy_data.size = size;
if (!info->transform_func (dest, meta, src,
_gst_meta_transform_copy, &copy_data)) {
GST_CAT_ERROR (GST_CAT_BUFFER,
"failed to copy meta %p of API type %s", meta,
g_type_name (info->api));
}
}
}
}
if (sharing_mem && src->pool != NULL) {
/* The new buffer references some of src's memories. We have to ensure that
* src buffer does not return to its buffer pool as long as its memories are
* used by other buffers. That would cause the buffer to be discarted by the
* pool because its memories are not writable. */
gst_buffer_add_parent_buffer_meta (dest, src);
}
return TRUE;
}
static GstBuffer *
gst_buffer_copy_with_flags (const GstBuffer * buffer, GstBufferCopyFlags flags)
{
GstBuffer *copy;
g_return_val_if_fail (buffer != NULL, NULL);
/* create a fresh new buffer */
copy = gst_buffer_new ();
/* copy what the 'flags' want from our parent */
/* FIXME why we can't pass const to gst_buffer_copy_into() ? */
if (!gst_buffer_copy_into (copy, (GstBuffer *) buffer, flags, 0, -1))
gst_buffer_replace (&copy, NULL);
if (copy)
GST_BUFFER_FLAG_UNSET (copy, GST_BUFFER_FLAG_TAG_MEMORY);
return copy;
}
static GstBuffer *
_gst_buffer_copy (const GstBuffer * buffer)
{
return gst_buffer_copy_with_flags (buffer, GST_BUFFER_COPY_ALL);
}
/**
* gst_buffer_copy_deep:
* @buf: a #GstBuffer.
*
* Creates a copy of the given buffer. This will make a newly allocated
* copy of the data the source buffer contains.
*
* Returns: (transfer full) (nullable): a new copy of @buf if the copy succeeded, %NULL otherwise.
*
* Since: 1.6
*/
GstBuffer *
gst_buffer_copy_deep (const GstBuffer * buffer)
{
return gst_buffer_copy_with_flags (buffer,
GST_BUFFER_COPY_ALL | GST_BUFFER_COPY_DEEP);
}
/* the default dispose function revives the buffer and returns it to the
* pool when there is a pool */
static gboolean
_gst_buffer_dispose (GstBuffer * buffer)
{
GstBufferPool *pool;
/* no pool, do free */
if ((pool = buffer->pool) == NULL)
return TRUE;
/* keep the buffer alive */
gst_buffer_ref (buffer);
/* return the buffer to the pool */
GST_CAT_LOG (GST_CAT_BUFFER, "release %p to pool %p", buffer, pool);
gst_buffer_pool_release_buffer (pool, buffer);
return FALSE;
}
static void
_gst_buffer_free (GstBuffer * buffer)
{
GstMetaItem *walk, *next;
guint i, len;
g_return_if_fail (buffer != NULL);
GST_CAT_LOG (GST_CAT_BUFFER, "finalize %p", buffer);
/* free our memory */
len = GST_BUFFER_MEM_LEN (buffer);
for (i = 0; i < len; i++) {
gst_memory_unlock (GST_BUFFER_MEM_PTR (buffer, i), GST_LOCK_FLAG_EXCLUSIVE);
gst_mini_object_remove_parent (GST_MINI_OBJECT_CAST (GST_BUFFER_MEM_PTR
(buffer, i)), GST_MINI_OBJECT_CAST (buffer));
gst_memory_unref (GST_BUFFER_MEM_PTR (buffer, i));
}
/* free metadata */
for (walk = GST_BUFFER_META (buffer); walk; walk = next) {
GstMeta *meta = &walk->meta;
const GstMetaInfo *info = meta->info;
/* call free_func if any */
if (info->free_func)
info->free_func (meta, buffer);
next = walk->next;
/* and free the slice */
g_free (walk);
}
#ifdef USE_POISONING
memset (buffer, 0xff, sizeof (GstBufferImpl));
#endif
g_free (buffer);
}
static void
gst_buffer_init (GstBufferImpl * buffer)
{
gst_mini_object_init (GST_MINI_OBJECT_CAST (buffer), 0, _gst_buffer_type,
(GstMiniObjectCopyFunction) _gst_buffer_copy,
(GstMiniObjectDisposeFunction) _gst_buffer_dispose,
(GstMiniObjectFreeFunction) _gst_buffer_free);
GST_BUFFER (buffer)->pool = NULL;
GST_BUFFER_PTS (buffer) = GST_CLOCK_TIME_NONE;
GST_BUFFER_DTS (buffer) = GST_CLOCK_TIME_NONE;
GST_BUFFER_DURATION (buffer) = GST_CLOCK_TIME_NONE;
GST_BUFFER_OFFSET (buffer) = GST_BUFFER_OFFSET_NONE;
GST_BUFFER_OFFSET_END (buffer) = GST_BUFFER_OFFSET_NONE;
GST_BUFFER_MEM_LEN (buffer) = 0;
GST_BUFFER_META (buffer) = NULL;
}
/**
* gst_buffer_new:
*
* Creates a newly allocated buffer without any data.
*
* Returns: (transfer full): the new #GstBuffer.
*/
GstBuffer *
gst_buffer_new (void)
{
GstBufferImpl *newbuf;
newbuf = g_new (GstBufferImpl, 1);
GST_CAT_LOG (GST_CAT_BUFFER, "new %p", newbuf);
gst_buffer_init (newbuf);
return GST_BUFFER_CAST (newbuf);
}
/**
* gst_buffer_new_allocate:
* @allocator: (transfer none) (allow-none): the #GstAllocator to use, or %NULL to use the
* default allocator
* @size: the size in bytes of the new buffer's data.
* @params: (transfer none) (allow-none): optional parameters
*
* Tries to create a newly allocated buffer with data of the given size and
* extra parameters from @allocator. If the requested amount of memory can't be
* allocated, %NULL will be returned. The allocated buffer memory is not cleared.
*
* When @allocator is %NULL, the default memory allocator will be used.
*
* Note that when @size == 0, the buffer will not have memory associated with it.
*
* Returns: (transfer full) (nullable): a new #GstBuffer
*/
GstBuffer *
gst_buffer_new_allocate (GstAllocator * allocator, gsize size,
GstAllocationParams * params)
{
GstBuffer *newbuf;
GstMemory *mem;
#if 0
guint8 *data;
gsize asize;
#endif
#if 1
if (size > 0) {
mem = gst_allocator_alloc (allocator, size, params);
if (G_UNLIKELY (mem == NULL))
goto no_memory;
} else {
mem = NULL;
}
newbuf = gst_buffer_new ();
if (mem != NULL) {
gst_memory_lock (mem, GST_LOCK_FLAG_EXCLUSIVE);
_memory_add (newbuf, -1, mem);
}
GST_CAT_LOG (GST_CAT_BUFFER,
"new buffer %p of size %" G_GSIZE_FORMAT " from allocator %p", newbuf,
size, allocator);
#endif
#if 0
asize = sizeof (GstBufferImpl) + size;
data = g_malloc (asize);
if (G_UNLIKELY (data == NULL))
goto no_memory;
newbuf = GST_BUFFER_CAST (data);
gst_buffer_init ((GstBufferImpl *) data, asize);
if (size > 0) {
mem = gst_memory_new_wrapped (0, data + sizeof (GstBufferImpl), NULL,
size, 0, size);
_memory_add (newbuf, -1, mem, TRUE);
}
#endif
#if 0
/* allocate memory and buffer, it might be interesting to do this but there
* are many complications. We need to keep the memory mapped to access the
* buffer fields and the memory for the buffer might be just very slow. We
* also need to do some more magic to get the alignment right. */
asize = sizeof (GstBufferImpl) + size;
mem = gst_allocator_alloc (allocator, asize, align);
if (G_UNLIKELY (mem == NULL))
goto no_memory;
/* map the data part and init the buffer in it, set the buffer size to 0 so
* that a finalize won't free the buffer */
data = gst_memory_map (mem, &asize, NULL, GST_MAP_WRITE);
gst_buffer_init ((GstBufferImpl *) data, 0);
gst_memory_unmap (mem);
/* strip off the buffer */
gst_memory_resize (mem, sizeof (GstBufferImpl), size);
newbuf = GST_BUFFER_CAST (data);
GST_BUFFER_BUFMEM (newbuf) = mem;
if (size > 0)
_memory_add (newbuf, -1, gst_memory_ref (mem), TRUE);
#endif
GST_BUFFER_FLAG_UNSET (newbuf, GST_BUFFER_FLAG_TAG_MEMORY);
return newbuf;
/* ERRORS */
no_memory:
{
GST_CAT_WARNING (GST_CAT_BUFFER,
"failed to allocate %" G_GSIZE_FORMAT " bytes", size);
return NULL;
}
}
/**
* gst_buffer_new_wrapped_full:
* @flags: #GstMemoryFlags
* @data: (array length=size) (element-type guint8) (transfer none): data to wrap
* @maxsize: allocated size of @data
* @offset: offset in @data
* @size: size of valid data
* @user_data: (allow-none): user_data
* @notify: (allow-none) (scope async) (closure user_data): called with @user_data when the memory is freed
*
* Allocates a new buffer that wraps the given memory. @data must point to
* @maxsize of memory, the wrapped buffer will have the region from @offset and
* @size visible.
*
* When the buffer is destroyed, @notify will be called with @user_data.
*
* The prefix/padding must be filled with 0 if @flags contains
* #GST_MEMORY_FLAG_ZERO_PREFIXED and #GST_MEMORY_FLAG_ZERO_PADDED respectively.
*
* Returns: (transfer full): a new #GstBuffer
*/
GstBuffer *
gst_buffer_new_wrapped_full (GstMemoryFlags flags, gpointer data,
gsize maxsize, gsize offset, gsize size, gpointer user_data,
GDestroyNotify notify)
{
GstMemory *mem;
GstBuffer *newbuf;
newbuf = gst_buffer_new ();
mem =
gst_memory_new_wrapped (flags, data, maxsize, offset, size, user_data,
notify);
gst_memory_lock (mem, GST_LOCK_FLAG_EXCLUSIVE);
_memory_add (newbuf, -1, mem);
GST_BUFFER_FLAG_UNSET (newbuf, GST_BUFFER_FLAG_TAG_MEMORY);
return newbuf;
}
/**
* gst_buffer_new_wrapped:
* @data: (array length=size) (element-type guint8) (transfer full): data to wrap
* @size: allocated size of @data
*
* Creates a new buffer that wraps the given @data. The memory will be freed
* with g_free() and will be marked writable.
*
* Returns: (transfer full): a new #GstBuffer
*/
GstBuffer *
gst_buffer_new_wrapped (gpointer data, gsize size)
{
return gst_buffer_new_wrapped_full (0, data, size, 0, size, data, g_free);
}
/**
* gst_buffer_new_wrapped_bytes:
* @bytes: (transfer none): a #GBytes to wrap
*
* Creates a new #GstBuffer that wraps the given @bytes. The data inside
* @bytes cannot be %NULL and the resulting buffer will be marked as read only.
*
* Returns: (transfer full): a new #GstBuffer wrapping @bytes
*
* Since: 1.16
*/
GstBuffer *
gst_buffer_new_wrapped_bytes (GBytes * bytes)
{
guint8 *bytes_data;
gsize size;
g_return_val_if_fail (bytes != NULL, NULL);
bytes_data = (guint8 *) g_bytes_get_data (bytes, &size);
g_return_val_if_fail (bytes_data != NULL, NULL);
return gst_buffer_new_wrapped_full (GST_MEMORY_FLAG_READONLY, bytes_data,
size, 0, size, g_bytes_ref (bytes), (GDestroyNotify) g_bytes_unref);
}
/**
* gst_buffer_new_memdup:
* @data: (array length=size) (element-type guint8) (transfer none): data to copy into new buffer
* @size: size of @data in bytes
*
* Creates a new buffer of size @size and fills it with a copy of @data.
*
* Returns: (transfer full): a new #GstBuffer
*
* Since: 1.20
*/
GstBuffer *
gst_buffer_new_memdup (gconstpointer data, gsize size)
{
gpointer data2 = g_memdup2 (data, size);
return gst_buffer_new_wrapped_full (0, data2, size, 0, size, data2, g_free);
}
/**
* gst_buffer_n_memory:
* @buffer: a #GstBuffer.
*
* Gets the amount of memory blocks that this buffer has. This amount is never
* larger than what gst_buffer_get_max_memory() returns.
*
* Returns: the number of memory blocks this buffer is made of.
*/
guint
gst_buffer_n_memory (GstBuffer * buffer)
{
g_return_val_if_fail (GST_IS_BUFFER (buffer), 0);
return GST_BUFFER_MEM_LEN (buffer);
}
/**
* gst_buffer_prepend_memory:
* @buffer: a #GstBuffer.
* @mem: (transfer full): a #GstMemory.
*
* Prepends the memory block @mem to @buffer. This function takes
* ownership of @mem and thus doesn't increase its refcount.
*
* This function is identical to gst_buffer_insert_memory() with an index of 0.
* See gst_buffer_insert_memory() for more details.
*/
void
gst_buffer_prepend_memory (GstBuffer * buffer, GstMemory * mem)
{
gst_buffer_insert_memory (buffer, 0, mem);
}
/**
* gst_buffer_append_memory:
* @buffer: a #GstBuffer.
* @mem: (transfer full): a #GstMemory.
*
* Appends the memory block @mem to @buffer. This function takes
* ownership of @mem and thus doesn't increase its refcount.
*
* This function is identical to gst_buffer_insert_memory() with an index of -1.
* See gst_buffer_insert_memory() for more details.
*/
void
gst_buffer_append_memory (GstBuffer * buffer, GstMemory * mem)
{
gst_buffer_insert_memory (buffer, -1, mem);
}
/**
* gst_buffer_insert_memory:
* @buffer: a #GstBuffer.
* @idx: the index to add the memory at, or -1 to append it to the end
* @mem: (transfer full): a #GstMemory.
*
* Inserts the memory block @mem into @buffer at @idx. This function takes ownership
* of @mem and thus doesn't increase its refcount.
*
* Only gst_buffer_get_max_memory() can be added to a buffer. If more memory is
* added, existing memory blocks will automatically be merged to make room for
* the new memory.
*/
void
gst_buffer_insert_memory (GstBuffer * buffer, gint idx, GstMemory * mem)
{
GstMemory *tmp;
g_return_if_fail (GST_IS_BUFFER (buffer));
g_return_if_fail (gst_buffer_is_writable (buffer));
g_return_if_fail (mem != NULL);
g_return_if_fail (idx == -1 ||
(idx >= 0 && idx <= GST_BUFFER_MEM_LEN (buffer)));
tmp = _memory_get_exclusive_reference (mem);
g_return_if_fail (tmp != NULL);
gst_memory_unref (mem);
_memory_add (buffer, idx, tmp);
}
static GstMemory *
_get_mapped (GstBuffer * buffer, guint idx, GstMapInfo * info,
GstMapFlags flags)
{
GstMemory *mem, *mapped;
mem = gst_memory_ref (GST_BUFFER_MEM_PTR (buffer, idx));
mapped = gst_memory_make_mapped (mem, info, flags);
if (mapped != mem) {
/* memory changed, lock new memory */
gst_mini_object_add_parent (GST_MINI_OBJECT_CAST (mapped),
GST_MINI_OBJECT_CAST (buffer));
gst_memory_lock (mapped, GST_LOCK_FLAG_EXCLUSIVE);
GST_BUFFER_MEM_PTR (buffer, idx) = mapped;
/* unlock old memory */
gst_memory_unlock (mem, GST_LOCK_FLAG_EXCLUSIVE);
gst_mini_object_remove_parent (GST_MINI_OBJECT_CAST (mem),
GST_MINI_OBJECT_CAST (buffer));
GST_BUFFER_FLAG_SET (buffer, GST_BUFFER_FLAG_TAG_MEMORY);
}
gst_memory_unref (mem);
return mapped;
}
/**
* gst_buffer_peek_memory:
* @buffer: a #GstBuffer.
* @idx: an index
*
* Gets the memory block at @idx in @buffer. The memory block stays valid until
* the memory block in @buffer is removed, replaced or merged, typically with
* any call that modifies the memory in @buffer.
*
* Returns: (transfer none) (nullable): the #GstMemory at @idx.
*/
GstMemory *
gst_buffer_peek_memory (GstBuffer * buffer, guint idx)
{
g_return_val_if_fail (GST_IS_BUFFER (buffer), NULL);
g_return_val_if_fail (idx < GST_BUFFER_MEM_LEN (buffer), NULL);
return GST_BUFFER_MEM_PTR (buffer, idx);
}
/**
* gst_buffer_get_memory:
* @buffer: a #GstBuffer.
* @idx: an index
*
* Gets the memory block at index @idx in @buffer.
*
* Returns: (transfer full) (nullable): a #GstMemory that contains the data of the
* memory block at @idx.
*/
GstMemory *
gst_buffer_get_memory (GstBuffer * buffer, guint idx)
{
return gst_buffer_get_memory_range (buffer, idx, 1);
}
/**
* gst_buffer_get_all_memory:
* @buffer: a #GstBuffer.
*
* Gets all the memory blocks in @buffer. The memory blocks will be merged
* into one large #GstMemory.
*
* Returns: (transfer full) (nullable): a #GstMemory that contains the merged memory.
*/
GstMemory *
gst_buffer_get_all_memory (GstBuffer * buffer)
{
return gst_buffer_get_memory_range (buffer, 0, -1);
}
/**
* gst_buffer_get_memory_range:
* @buffer: a #GstBuffer.
* @idx: an index
* @length: a length
*
* Gets @length memory blocks in @buffer starting at @idx. The memory blocks will
* be merged into one large #GstMemory.
*
* If @length is -1, all memory starting from @idx is merged.
*
* Returns: (transfer full) (nullable): a #GstMemory that contains the merged data of @length
* blocks starting at @idx.
*/
GstMemory *
gst_buffer_get_memory_range (GstBuffer * buffer, guint idx, gint length)
{
guint len;
GST_CAT_DEBUG (GST_CAT_BUFFER, "idx %u, length %d", idx, length);
g_return_val_if_fail (GST_IS_BUFFER (buffer), NULL);
len = GST_BUFFER_MEM_LEN (buffer);
g_return_val_if_fail ((len == 0 && idx == 0 && length == -1) ||
(length == -1 && idx < len) || (length > 0 && length + idx <= len), NULL);
if (length == -1)
length = len - idx;
return _get_merged_memory (buffer, idx, length);
}
/**
* gst_buffer_replace_memory:
* @buffer: a #GstBuffer.
* @idx: an index
* @mem: (transfer full): a #GstMemory
*
* Replaces the memory block at index @idx in @buffer with @mem.
*/
void
gst_buffer_replace_memory (GstBuffer * buffer, guint idx, GstMemory * mem)
{
gst_buffer_replace_memory_range (buffer, idx, 1, mem);
}
/**
* gst_buffer_replace_all_memory:
* @buffer: a #GstBuffer.
* @mem: (transfer full): a #GstMemory
*
* Replaces all memory in @buffer with @mem.
*/
void
gst_buffer_replace_all_memory (GstBuffer * buffer, GstMemory * mem)
{
gst_buffer_replace_memory_range (buffer, 0, -1, mem);
}
/**
* gst_buffer_replace_memory_range:
* @buffer: a #GstBuffer.
* @idx: an index
* @length: a length, should not be 0
* @mem: (transfer full): a #GstMemory
*
* Replaces @length memory blocks in @buffer starting at @idx with @mem.
*
* If @length is -1, all memory starting from @idx will be removed and
* replaced with @mem.
*
* @buffer should be writable.
*/
void
gst_buffer_replace_memory_range (GstBuffer * buffer, guint idx, gint length,
GstMemory * mem)
{
guint len;
g_return_if_fail (GST_IS_BUFFER (buffer));
g_return_if_fail (gst_buffer_is_writable (buffer));
GST_CAT_DEBUG (GST_CAT_BUFFER, "idx %u, length %d, %p", idx, length, mem);
len = GST_BUFFER_MEM_LEN (buffer);
g_return_if_fail ((len == 0 && idx == 0 && length == -1) ||
(length == -1 && idx < len) || (length > 0 && length + idx <= len));
if (length == -1)
length = len - idx;
_replace_memory (buffer, len, idx, length, mem);
}
/**
* gst_buffer_remove_memory:
* @buffer: a #GstBuffer.
* @idx: an index
*
* Removes the memory block in @b at index @i.
*/
void
gst_buffer_remove_memory (GstBuffer * buffer, guint idx)
{
gst_buffer_remove_memory_range (buffer, idx, 1);
}
/**
* gst_buffer_remove_all_memory:
* @buffer: a #GstBuffer.
*
* Removes all the memory blocks in @buffer.
*/
void
gst_buffer_remove_all_memory (GstBuffer * buffer)
{
if (GST_BUFFER_MEM_LEN (buffer))
gst_buffer_remove_memory_range (buffer, 0, -1);
}
/**
* gst_buffer_remove_memory_range:
* @buffer: a #GstBuffer.
* @idx: an index
* @length: a length
*
* Removes @length memory blocks in @buffer starting from @idx.
*
* @length can be -1, in which case all memory starting from @idx is removed.
*/
void
gst_buffer_remove_memory_range (GstBuffer * buffer, guint idx, gint length)
{
guint len;
g_return_if_fail (GST_IS_BUFFER (buffer));
g_return_if_fail (gst_buffer_is_writable (buffer));
GST_CAT_DEBUG (GST_CAT_BUFFER, "idx %u, length %d", idx, length);
len = GST_BUFFER_MEM_LEN (buffer);
g_return_if_fail ((len == 0 && idx == 0 && length == -1) ||
(length == -1 && idx < len) || length + idx <= len);
if (length == -1)
length = len - idx;
_replace_memory (buffer, len, idx, length, NULL);
}
/**
* gst_buffer_find_memory:
* @buffer: a #GstBuffer.
* @offset: an offset
* @size: a size
* @idx: (out): pointer to index
* @length: (out): pointer to length
* @skip: (out): pointer to skip
*
* Finds the memory blocks that span @size bytes starting from @offset
* in @buffer.
*
* When this function returns %TRUE, @idx will contain the index of the first
* memory block where the byte for @offset can be found and @length contains the
* number of memory blocks containing the @size remaining bytes. @skip contains
* the number of bytes to skip in the memory block at @idx to get to the byte
* for @offset.
*
* @size can be -1 to get all the memory blocks after @idx.
*
* Returns: %TRUE when @size bytes starting from @offset could be found in
* @buffer and @idx, @length and @skip will be filled.
*/
gboolean
gst_buffer_find_memory (GstBuffer * buffer, gsize offset, gsize size,
guint * idx, guint * length, gsize * skip)
{
guint i, len, found;
g_return_val_if_fail (GST_IS_BUFFER (buffer), FALSE);
g_return_val_if_fail (idx != NULL, FALSE);
g_return_val_if_fail (length != NULL, FALSE);
g_return_val_if_fail (skip != NULL, FALSE);
len = GST_BUFFER_MEM_LEN (buffer);
found = 0;
for (i = 0; i < len; i++) {
GstMemory *mem;
gsize s;
mem = GST_BUFFER_MEM_PTR (buffer, i);
s = mem->size;
if (s <= offset) {
/* block before offset, or empty block, skip */
offset -= s;
} else {
/* block after offset */
if (found == 0) {
/* first block, remember index and offset */
*idx = i;
*skip = offset;
if (size == -1) {
/* return remaining blocks */
*length = len - i;
return TRUE;
}
s -= offset;
offset = 0;
}
/* count the amount of found bytes */
found += s;
if (found >= size) {
/* we have enough bytes */
*length = i - *idx + 1;
return TRUE;
}
}
}
return FALSE;
}
/**
* gst_buffer_is_memory_range_writable:
* @buffer: a #GstBuffer.
* @idx: an index
* @length: a length, should not be 0
*
* Checks if @length memory blocks in @buffer starting from @idx are writable.
*
* @length can be -1 to check all the memory blocks after @idx.
*
* Note that this function does not check if @buffer is writable, use
* gst_buffer_is_writable() to check that if needed.
*
* Returns: %TRUE if the memory range is writable
*
* Since: 1.4
*/
gboolean
gst_buffer_is_memory_range_writable (GstBuffer * buffer, guint idx, gint length)
{
guint i, len;
g_return_val_if_fail (GST_IS_BUFFER (buffer), FALSE);
GST_CAT_DEBUG (GST_CAT_BUFFER, "idx %u, length %d", idx, length);
len = GST_BUFFER_MEM_LEN (buffer);
g_return_val_if_fail ((len == 0 && idx == 0 && length == -1) ||
(length == -1 && idx < len) || (length > 0 && length + idx <= len),
FALSE);
if (length == -1)
len -= idx;
else
len = length;
for (i = 0; i < len; i++) {
if (!gst_memory_is_writable (GST_BUFFER_MEM_PTR (buffer, i + idx)))
return FALSE;
}
return TRUE;
}
/**
* gst_buffer_is_all_memory_writable:
* @buffer: a #GstBuffer.
*
* Checks if all memory blocks in @buffer are writable.
*
* Note that this function does not check if @buffer is writable, use
* gst_buffer_is_writable() to check that if needed.
*
* Returns: %TRUE if all memory blocks in @buffer are writable
*
* Since: 1.4
*/
gboolean
gst_buffer_is_all_memory_writable (GstBuffer * buffer)
{
return gst_buffer_is_memory_range_writable (buffer, 0, -1);
}
/**
* gst_buffer_get_sizes:
* @buffer: a #GstBuffer.
* @offset: (out) (allow-none): a pointer to the offset
* @maxsize: (out) (allow-none): a pointer to the maxsize
*
* Gets the total size of the memory blocks in @buffer.
*
* When not %NULL, @offset will contain the offset of the data in the
* first memory block in @buffer and @maxsize will contain the sum of
* the size and @offset and the amount of extra padding on the last
* memory block. @offset and @maxsize can be used to resize the
* buffer memory blocks with gst_buffer_resize().
*
* Returns: total size of the memory blocks in @buffer.
*/
gsize
gst_buffer_get_sizes (GstBuffer * buffer, gsize * offset, gsize * maxsize)
{
return gst_buffer_get_sizes_range (buffer, 0, -1, offset, maxsize);
}
/**
* gst_buffer_get_size:
* @buffer: a #GstBuffer.
*
* Gets the total size of the memory blocks in @buffer.
*
* Returns: total size of the memory blocks in @buffer.
*/
gsize
gst_buffer_get_size (GstBuffer * buffer)
{
guint i;
gsize size, len;
g_return_val_if_fail (GST_IS_BUFFER (buffer), 0);
/* FAST PATH */
len = GST_BUFFER_MEM_LEN (buffer);
for (i = 0, size = 0; i < len; i++)
size += GST_BUFFER_MEM_PTR (buffer, i)->size;
return size;
}
/**
* gst_buffer_get_sizes_range:
* @buffer: a #GstBuffer.
* @idx: an index
* @length: a length
* @offset: (out) (allow-none): a pointer to the offset
* @maxsize: (out) (allow-none): a pointer to the maxsize
*
* Gets the total size of @length memory blocks stating from @idx in @buffer.
*
* When not %NULL, @offset will contain the offset of the data in the
* memory block in @buffer at @idx and @maxsize will contain the sum of the size
* and @offset and the amount of extra padding on the memory block at @idx +
* @length -1.
* @offset and @maxsize can be used to resize the buffer memory blocks with
* gst_buffer_resize_range().
*
* Returns: total size of @length memory blocks starting at @idx in @buffer.
*/
gsize
gst_buffer_get_sizes_range (GstBuffer * buffer, guint idx, gint length,
gsize * offset, gsize * maxsize)
{
guint len;
gsize size;
GstMemory *mem;
g_return_val_if_fail (GST_IS_BUFFER (buffer), 0);
len = GST_BUFFER_MEM_LEN (buffer);
g_return_val_if_fail ((len == 0 && idx == 0 && length == -1) ||
(length == -1 && idx < len) || (length + idx <= len), 0);
if (length == -1)
length = len - idx;
if (G_LIKELY (length == 1)) {
/* common case */
mem = GST_BUFFER_MEM_PTR (buffer, idx);
size = gst_memory_get_sizes (mem, offset, maxsize);
} else if (offset == NULL && maxsize == NULL) {
/* FAST PATH ! */
guint i, end;
size = 0;
end = idx + length;
for (i = idx; i < end; i++) {
mem = GST_BUFFER_MEM_PTR (buffer, i);
size += mem->size;
}
} else {
guint i, end;
gsize extra, offs;
end = idx + length;
size = offs = extra = 0;
for (i = idx; i < end; i++) {
gsize s, o, ms;
mem = GST_BUFFER_MEM_PTR (buffer, i);
s = gst_memory_get_sizes (mem, &o, &ms);
if (s) {
if (size == 0)
/* first size, take accumulated data before as the offset */
offs = extra + o;
/* add sizes */
size += s;
/* save the amount of data after this block */
extra = ms - (o + s);
} else {
/* empty block, add as extra */
extra += ms;
}
}
if (offset)
*offset = offs;
if (maxsize)
*maxsize = offs + size + extra;
}
return size;
}
/**
* gst_buffer_resize:
* @buffer: a #GstBuffer.
* @offset: the offset adjustment
* @size: the new size or -1 to just adjust the offset
*
* Sets the offset and total size of the memory blocks in @buffer.
*/
void
gst_buffer_resize (GstBuffer * buffer, gssize offset, gssize size)
{
gst_buffer_resize_range (buffer, 0, -1, offset, size);
}
/**
* gst_buffer_set_size:
* @buffer: a #GstBuffer.
* @size: the new size
*
* Sets the total size of the memory blocks in @buffer.
*/
void
gst_buffer_set_size (GstBuffer * buffer, gssize size)
{
gst_buffer_resize_range (buffer, 0, -1, 0, size);
}
/**
* gst_buffer_resize_range:
* @buffer: a #GstBuffer.
* @idx: an index
* @length: a length
* @offset: the offset adjustment
* @size: the new size or -1 to just adjust the offset
*
* Sets the total size of the @length memory blocks starting at @idx in
* @buffer
*
* Returns: %TRUE if resizing succeeded, %FALSE otherwise.
*/
gboolean
gst_buffer_resize_range (GstBuffer * buffer, guint idx, gint length,
gssize offset, gssize size)
{
guint i, len, end;
gsize bsize, bufsize, bufoffs, bufmax;
g_return_val_if_fail (gst_buffer_is_writable (buffer), FALSE);
g_return_val_if_fail (size >= -1, FALSE);
len = GST_BUFFER_MEM_LEN (buffer);
g_return_val_if_fail ((len == 0 && idx == 0 && length == -1) ||
(length == -1 && idx < len) || (length + idx <= len), FALSE);
if (length == -1)
length = len - idx;
bufsize = gst_buffer_get_sizes_range (buffer, idx, length, &bufoffs, &bufmax);
GST_CAT_LOG (GST_CAT_BUFFER, "trim %p %" G_GSSIZE_FORMAT "-%" G_GSSIZE_FORMAT
" size:%" G_GSIZE_FORMAT " offs:%" G_GSIZE_FORMAT " max:%"
G_GSIZE_FORMAT, buffer, offset, size, bufsize, bufoffs, bufmax);
/* we can't go back further than the current offset or past the end of the
* buffer */
g_return_val_if_fail ((offset < 0 && bufoffs >= -offset) || (offset >= 0
&& bufoffs + offset <= bufmax), FALSE);
if (size == -1) {
g_return_val_if_fail (bufsize >= offset, FALSE);
size = bufsize - offset;
}
g_return_val_if_fail (bufmax >= bufoffs + offset + size, FALSE);
/* no change */
if (offset == 0 && size == bufsize)
return TRUE;
end = idx + length;
/* copy and trim */
for (i = idx; i < end; i++) {
GstMemory *mem;
gsize left, noffs;
mem = GST_BUFFER_MEM_PTR (buffer, i);
bsize = mem->size;
noffs = 0;
/* last buffer always gets resized to the remaining size */
if (i + 1 == end)
left = size;
/* shrink buffers before the offset */
else if ((gssize) bsize <= offset) {
left = 0;
noffs = offset - bsize;
offset = 0;
}
/* clip other buffers */
else
left = MIN (bsize - offset, size);
if (offset != 0 || left != bsize) {
if (gst_memory_is_writable (mem)) {
gst_memory_resize (mem, offset, left);
} else {
GstMemory *newmem = NULL;
if (!GST_MEMORY_IS_NO_SHARE (mem))
newmem = gst_memory_share (mem, offset, left);
if (!newmem)
newmem = gst_memory_copy (mem, offset, left);
if (newmem == NULL)
return FALSE;
gst_mini_object_add_parent (GST_MINI_OBJECT_CAST (newmem),
GST_MINI_OBJECT_CAST (buffer));
gst_memory_lock (newmem, GST_LOCK_FLAG_EXCLUSIVE);
GST_BUFFER_MEM_PTR (buffer, i) = newmem;
gst_memory_unlock (mem, GST_LOCK_FLAG_EXCLUSIVE);
gst_mini_object_remove_parent (GST_MINI_OBJECT_CAST (mem),
GST_MINI_OBJECT_CAST (buffer));
gst_memory_unref (mem);
GST_BUFFER_FLAG_SET (buffer, GST_BUFFER_FLAG_TAG_MEMORY);
}
}
offset = noffs;
size -= left;
}
return TRUE;
}
/**
* gst_buffer_map:
* @buffer: a #GstBuffer.
* @info: (out caller-allocates): info about the mapping
* @flags: flags for the mapping
*
* Fills @info with the #GstMapInfo of all merged memory blocks in @buffer.
*
* @flags describe the desired access of the memory. When @flags is
* #GST_MAP_WRITE, @buffer should be writable (as returned from
* gst_buffer_is_writable()).
*
* When @buffer is writable but the memory isn't, a writable copy will
* automatically be created and returned. The readonly copy of the
* buffer memory will then also be replaced with this writable copy.
*
* The memory in @info should be unmapped with gst_buffer_unmap() after
* usage.
*
* Returns: %TRUE if the map succeeded and @info contains valid data.
*/
gboolean
gst_buffer_map (GstBuffer * buffer, GstMapInfo * info, GstMapFlags flags)
{
return gst_buffer_map_range (buffer, 0, -1, info, flags);
}
/**
* gst_buffer_map_range:
* @buffer: a #GstBuffer.
* @idx: an index
* @length: a length
* @info: (out caller-allocates): info about the mapping
* @flags: flags for the mapping
*
* Fills @info with the #GstMapInfo of @length merged memory blocks
* starting at @idx in @buffer. When @length is -1, all memory blocks starting
* from @idx are merged and mapped.
*
* @flags describe the desired access of the memory. When @flags is
* #GST_MAP_WRITE, @buffer should be writable (as returned from
* gst_buffer_is_writable()).
*
* When @buffer is writable but the memory isn't, a writable copy will
* automatically be created and returned. The readonly copy of the buffer memory
* will then also be replaced with this writable copy.
*
* The memory in @info should be unmapped with gst_buffer_unmap() after usage.
*
* Returns: %TRUE if the map succeeded and @info contains valid
* data.
*/
gboolean
gst_buffer_map_range (GstBuffer * buffer, guint idx, gint length,
GstMapInfo * info, GstMapFlags flags)
{
GstMemory *mem, *nmem;
gboolean write, writable;
gsize len;
g_return_val_if_fail (GST_IS_BUFFER (buffer), FALSE);
g_return_val_if_fail (info != NULL, FALSE);
len = GST_BUFFER_MEM_LEN (buffer);
g_return_val_if_fail ((len == 0 && idx == 0 && length == -1) ||
(length == -1 && idx < len) || (length > 0
&& length + idx <= len), FALSE);
GST_CAT_LOG (GST_CAT_BUFFER, "buffer %p, idx %u, length %d, flags %04x",
buffer, idx, length, flags);
write = (flags & GST_MAP_WRITE) != 0;
writable = gst_buffer_is_writable (buffer);
/* check if we can write when asked for write access */
if (G_UNLIKELY (write && !writable))
goto not_writable;
if (length == -1)
length = len - idx;
mem = _get_merged_memory (buffer, idx, length);
if (G_UNLIKELY (mem == NULL))
goto no_memory;
/* now try to map */
nmem = gst_memory_make_mapped (mem, info, flags);
if (G_UNLIKELY (nmem == NULL))
goto cannot_map;
/* if we merged or when the map returned a different memory, we try to replace
* the memory in the buffer */
if (G_UNLIKELY (length > 1 || nmem != mem)) {
/* if the buffer is writable, replace the memory */
if (writable) {
_replace_memory (buffer, len, idx, length, gst_memory_ref (nmem));
} else {
if (len > 1) {
GST_CAT_DEBUG (GST_CAT_PERFORMANCE,
"temporary mapping for memory %p in buffer %p", nmem, buffer);
}
}
}
return TRUE;
/* ERROR */
not_writable:
{
GST_WARNING ("write map requested on non-writable buffer");
g_critical ("write map requested on non-writable buffer");
memset (info, 0, sizeof (GstMapInfo));
return FALSE;
}
no_memory:
{
/* empty buffer, we need to return NULL */
GST_DEBUG ("can't get buffer memory");
memset (info, 0, sizeof (GstMapInfo));
return TRUE;
}
cannot_map:
{
GST_DEBUG ("cannot map memory");
memset (info, 0, sizeof (GstMapInfo));
return FALSE;
}
}
/**
* gst_buffer_unmap:
* @buffer: a #GstBuffer.
* @info: a #GstMapInfo
*
* Releases the memory previously mapped with gst_buffer_map().
*/
void
gst_buffer_unmap (GstBuffer * buffer, GstMapInfo * info)
{
g_return_if_fail (GST_IS_BUFFER (buffer));
g_return_if_fail (info != NULL);
_gst_buffer_map_info_clear ((GstBufferMapInfo *) info);
}
/**
* gst_buffer_fill:
* @buffer: a #GstBuffer.
* @offset: the offset to fill
* @src: (array length=size) (element-type guint8): the source address
* @size: the size to fill
*
* Copies @size bytes from @src to @buffer at @offset.
*
* Returns: The amount of bytes copied. This value can be lower than @size
* when @buffer did not contain enough data.
*/
gsize
gst_buffer_fill (GstBuffer * buffer, gsize offset, gconstpointer src,
gsize size)
{
gsize i, len, left;
const guint8 *ptr = src;
g_return_val_if_fail (GST_IS_BUFFER (buffer), 0);
g_return_val_if_fail (gst_buffer_is_writable (buffer), 0);
g_return_val_if_fail (src != NULL || size == 0, 0);
GST_CAT_LOG (GST_CAT_BUFFER,
"buffer %p, offset %" G_GSIZE_FORMAT ", size %" G_GSIZE_FORMAT, buffer,
offset, size);
len = GST_BUFFER_MEM_LEN (buffer);
left = size;
for (i = 0; i < len && left > 0; i++) {
GstMapInfo info;
gsize tocopy;
GstMemory *mem;
mem = _get_mapped (buffer, i, &info, GST_MAP_WRITE);
if (info.size > offset) {
/* we have enough */
tocopy = MIN (info.size - offset, left);
memcpy ((guint8 *) info.data + offset, ptr, tocopy);
left -= tocopy;
ptr += tocopy;
offset = 0;
} else {
/* offset past buffer, skip */
offset -= info.size;
}
gst_memory_unmap (mem, &info);
}
return size - left;
}
/**
* gst_buffer_extract:
* @buffer: a #GstBuffer.
* @offset: the offset to extract
* @dest: (out caller-allocates) (array length=size) (element-type guint8):
* the destination address
* @size: the size to extract
*
* Copies @size bytes starting from @offset in @buffer to @dest.
*
* Returns: The amount of bytes extracted. This value can be lower than @size
* when @buffer did not contain enough data.
*/
gsize
gst_buffer_extract (GstBuffer * buffer, gsize offset, gpointer dest, gsize size)
{
gsize i, len, left;
guint8 *ptr = dest;
g_return_val_if_fail (GST_IS_BUFFER (buffer), 0);
g_return_val_if_fail (dest != NULL, 0);
GST_CAT_LOG (GST_CAT_BUFFER,
"buffer %p, offset %" G_GSIZE_FORMAT ", size %" G_GSIZE_FORMAT, buffer,
offset, size);
len = GST_BUFFER_MEM_LEN (buffer);
left = size;
for (i = 0; i < len && left > 0; i++) {
GstMapInfo info;
gsize tocopy;
GstMemory *mem;
mem = _get_mapped (buffer, i, &info, GST_MAP_READ);
if (info.size > offset) {
/* we have enough */
tocopy = MIN (info.size - offset, left);
memcpy (ptr, (guint8 *) info.data + offset, tocopy);
left -= tocopy;
ptr += tocopy;
offset = 0;
} else {
/* offset past buffer, skip */
offset -= info.size;
}
gst_memory_unmap (mem, &info);
}
return size - left;
}
/**
* gst_buffer_memcmp:
* @buffer: a #GstBuffer.
* @offset: the offset in @buffer
* @mem: (array length=size) (element-type guint8): the memory to compare
* @size: the size to compare
*
* Compares @size bytes starting from @offset in @buffer with the memory in @mem.
*
* Returns: 0 if the memory is equal.
*/
gint
gst_buffer_memcmp (GstBuffer * buffer, gsize offset, gconstpointer mem,
gsize size)
{
gsize i, len;
const guint8 *ptr = mem;
gint res = 0;
g_return_val_if_fail (GST_IS_BUFFER (buffer), 0);
g_return_val_if_fail (mem != NULL, 0);
GST_CAT_LOG (GST_CAT_BUFFER,
"buffer %p, offset %" G_GSIZE_FORMAT ", size %" G_GSIZE_FORMAT, buffer,
offset, size);
if (G_UNLIKELY (gst_buffer_get_size (buffer) < offset + size))
return -1;
len = GST_BUFFER_MEM_LEN (buffer);
for (i = 0; i < len && size > 0 && res == 0; i++) {
GstMapInfo info;
gsize tocmp;
GstMemory *mem;
mem = _get_mapped (buffer, i, &info, GST_MAP_READ);
if (info.size > offset) {
/* we have enough */
tocmp = MIN (info.size - offset, size);
res = memcmp (ptr, (guint8 *) info.data + offset, tocmp);
size -= tocmp;
ptr += tocmp;
offset = 0;
} else {
/* offset past buffer, skip */
offset -= info.size;
}
gst_memory_unmap (mem, &info);
}
return res;
}
/**
* gst_buffer_memset:
* @buffer: a #GstBuffer.
* @offset: the offset in @buffer
* @val: the value to set
* @size: the size to set
*
* Fills @buf with @size bytes with @val starting from @offset.
*
* Returns: The amount of bytes filled. This value can be lower than @size
* when @buffer did not contain enough data.
*/
gsize
gst_buffer_memset (GstBuffer * buffer, gsize offset, guint8 val, gsize size)
{
gsize i, len, left;
g_return_val_if_fail (GST_IS_BUFFER (buffer), 0);
g_return_val_if_fail (gst_buffer_is_writable (buffer), 0);
GST_CAT_LOG (GST_CAT_BUFFER,
"buffer %p, offset %" G_GSIZE_FORMAT ", val %02x, size %" G_GSIZE_FORMAT,
buffer, offset, val, size);
len = GST_BUFFER_MEM_LEN (buffer);
left = size;
for (i = 0; i < len && left > 0; i++) {
GstMapInfo info;
gsize toset;
GstMemory *mem;
mem = _get_mapped (buffer, i, &info, GST_MAP_WRITE);
if (info.size > offset) {
/* we have enough */
toset = MIN (info.size - offset, left);
memset ((guint8 *) info.data + offset, val, toset);
left -= toset;
offset = 0;
} else {
/* offset past buffer, skip */
offset -= info.size;
}
gst_memory_unmap (mem, &info);
}
return size - left;
}
/**
* gst_buffer_copy_region:
* @parent: a #GstBuffer.
* @flags: the #GstBufferCopyFlags
* @offset: the offset into parent #GstBuffer at which the new sub-buffer
* begins.
* @size: the size of the new #GstBuffer sub-buffer, in bytes. If -1, all
* data is copied.
*
* Creates a sub-buffer from @parent at @offset and @size.
* This sub-buffer uses the actual memory space of the parent buffer.
* This function will copy the offset and timestamp fields when the
* offset is 0. If not, they will be set to #GST_CLOCK_TIME_NONE and
* #GST_BUFFER_OFFSET_NONE.
* If @offset equals 0 and @size equals the total size of @buffer, the
* duration and offset end fields are also copied. If not they will be set
* to #GST_CLOCK_TIME_NONE and #GST_BUFFER_OFFSET_NONE.
*
* Returns: (transfer full) (nullable): the new #GstBuffer or %NULL if copying
* failed.
*/
GstBuffer *
gst_buffer_copy_region (GstBuffer * buffer, GstBufferCopyFlags flags,
gsize offset, gsize size)
{
GstBuffer *copy;
g_return_val_if_fail (buffer != NULL, NULL);
/* create the new buffer */
copy = gst_buffer_new ();
GST_CAT_LOG (GST_CAT_BUFFER, "new region copy %p of %p %" G_GSIZE_FORMAT
"-%" G_GSIZE_FORMAT, copy, buffer, offset, size);
if (!gst_buffer_copy_into (copy, buffer, flags, offset, size))
gst_buffer_replace (&copy, NULL);
return copy;
}
/**
* gst_buffer_append:
* @buf1: (transfer full): the first source #GstBuffer to append.
* @buf2: (transfer full): the second source #GstBuffer to append.
*
* Appends all the memory from @buf2 to @buf1. The result buffer will contain a
* concatenation of the memory of @buf1 and @buf2.
*
* Returns: (transfer full): the new #GstBuffer that contains the memory
* of the two source buffers.
*/
GstBuffer *
gst_buffer_append (GstBuffer * buf1, GstBuffer * buf2)
{
return gst_buffer_append_region (buf1, buf2, 0, -1);
}
/**
* gst_buffer_append_region:
* @buf1: (transfer full): the first source #GstBuffer to append.
* @buf2: (transfer full): the second source #GstBuffer to append.
* @offset: the offset in @buf2
* @size: the size or -1 of @buf2
*
* Appends @size bytes at @offset from @buf2 to @buf1. The result buffer will
* contain a concatenation of the memory of @buf1 and the requested region of
* @buf2.
*
* Returns: (transfer full): the new #GstBuffer that contains the memory
* of the two source buffers.
*/
GstBuffer *
gst_buffer_append_region (GstBuffer * buf1, GstBuffer * buf2, gssize offset,
gssize size)
{
gsize i, len;
g_return_val_if_fail (GST_IS_BUFFER (buf1), NULL);
g_return_val_if_fail (GST_IS_BUFFER (buf2), NULL);
buf1 = gst_buffer_make_writable (buf1);
buf2 = gst_buffer_make_writable (buf2);
gst_buffer_resize (buf2, offset, size);
len = GST_BUFFER_MEM_LEN (buf2);
for (i = 0; i < len; i++) {
GstMemory *mem;
mem = GST_BUFFER_MEM_PTR (buf2, i);
gst_mini_object_remove_parent (GST_MINI_OBJECT_CAST (mem),
GST_MINI_OBJECT_CAST (buf2));
GST_BUFFER_MEM_PTR (buf2, i) = NULL;
_memory_add (buf1, -1, mem);
}
GST_BUFFER_MEM_LEN (buf2) = 0;
GST_BUFFER_FLAG_SET (buf2, GST_BUFFER_FLAG_TAG_MEMORY);
gst_buffer_unref (buf2);
return buf1;
}
/**
* gst_buffer_get_meta:
* @buffer: a #GstBuffer
* @api: the #GType of an API
*
* Gets the metadata for @api on buffer. When there is no such metadata, %NULL is
* returned. If multiple metadata with the given @api are attached to this
* buffer only the first one is returned. To handle multiple metadata with a
* given API use gst_buffer_iterate_meta() or gst_buffer_foreach_meta() instead
* and check the `meta->info.api` member for the API type.
*
* Returns: (transfer none) (nullable): the metadata for @api on @buffer.
*/
GstMeta *
gst_buffer_get_meta (GstBuffer * buffer, GType api)
{
GstMetaItem *item;
GstMeta *result = NULL;
g_return_val_if_fail (buffer != NULL, NULL);
g_return_val_if_fail (api != 0, NULL);
/* find GstMeta of the requested API */
for (item = GST_BUFFER_META (buffer); item; item = item->next) {
GstMeta *meta = &item->meta;
if (meta->info->api == api) {
result = meta;
break;
}
}
return result;
}
/**
* gst_buffer_get_n_meta:
* @buffer: a #GstBuffer
* @api_type: the #GType of an API
*
* Returns: number of metas of type @api_type on @buffer.
*
* Since: 1.14
*/
guint
gst_buffer_get_n_meta (GstBuffer * buffer, GType api_type)
{
gpointer state = NULL;
GstMeta *meta;
guint n = 0;
while ((meta = gst_buffer_iterate_meta_filtered (buffer, &state, api_type)))
++n;
return n;
}
/**
* gst_buffer_add_meta:
* @buffer: a #GstBuffer
* @info: a #GstMetaInfo
* @params: params for @info
*
* Adds metadata for @info to @buffer using the parameters in @params.
*
* Returns: (transfer none) (nullable): the metadata for the api in @info on @buffer.
*/
GstMeta *
gst_buffer_add_meta (GstBuffer * buffer, const GstMetaInfo * info,
gpointer params)
{
GstMetaItem *item;
GstMeta *result = NULL;
gsize size;
g_return_val_if_fail (buffer != NULL, NULL);
g_return_val_if_fail (info != NULL, NULL);
g_return_val_if_fail (gst_buffer_is_writable (buffer), NULL);
/* create a new slice */
size = ITEM_SIZE (info);
/* We warn in gst_meta_register() about metas without
* init function but let's play safe here and prevent
* uninitialized memory
*/
if (!info->init_func)
item = g_malloc0 (size);
else
item = g_malloc (size);
result = &item->meta;
result->info = info;
result->flags = GST_META_FLAG_NONE;
GST_CAT_DEBUG (GST_CAT_BUFFER,
"alloc metadata %p (%s) of size %" G_GSIZE_FORMAT, result,
g_type_name (info->type), info->size);
/* call the init_func when needed */
if (info->init_func)
if (!info->init_func (result, params, buffer))
goto init_failed;
item->seq_num = gst_atomic_int64_inc (&meta_seq);
item->next = NULL;
if (!GST_BUFFER_META (buffer)) {
GST_BUFFER_META (buffer) = item;
GST_BUFFER_TAIL_META (buffer) = item;
} else {
GST_BUFFER_TAIL_META (buffer)->next = item;
GST_BUFFER_TAIL_META (buffer) = item;
}
return result;
init_failed:
{
g_free (item);
return NULL;
}
}
/**
* gst_buffer_remove_meta:
* @buffer: a #GstBuffer
* @meta: a #GstMeta
*
* Removes the metadata for @meta on @buffer.
*
* Returns: %TRUE if the metadata existed and was removed, %FALSE if no such
* metadata was on @buffer.
*/
gboolean
gst_buffer_remove_meta (GstBuffer * buffer, GstMeta * meta)
{
GstMetaItem *walk, *prev;
g_return_val_if_fail (buffer != NULL, FALSE);
g_return_val_if_fail (meta != NULL, FALSE);
g_return_val_if_fail (gst_buffer_is_writable (buffer), FALSE);
g_return_val_if_fail (!GST_META_FLAG_IS_SET (meta, GST_META_FLAG_LOCKED),
FALSE);
/* find the metadata and delete */
prev = GST_BUFFER_META (buffer);
for (walk = prev; walk; walk = walk->next) {
GstMeta *m = &walk->meta;
if (m == meta) {
const GstMetaInfo *info = meta->info;
/* remove from list */
if (GST_BUFFER_TAIL_META (buffer) == walk) {
if (prev != walk)
GST_BUFFER_TAIL_META (buffer) = prev;
else
GST_BUFFER_TAIL_META (buffer) = NULL;
}
if (GST_BUFFER_META (buffer) == walk)
GST_BUFFER_META (buffer) = walk->next;
else
prev->next = walk->next;
/* call free_func if any */
if (info->free_func)
info->free_func (m, buffer);
/* and free the slice */
g_free (walk);
break;
}
prev = walk;
}
return walk != NULL;
}
/**
* gst_buffer_iterate_meta: (skip)
* @buffer: a #GstBuffer
* @state: (out caller-allocates): an opaque state pointer
*
* Retrieves the next #GstMeta after @current. If @state points
* to %NULL, the first metadata is returned.
*
* @state will be updated with an opaque state pointer
*
* Returns: (transfer none) (nullable): The next #GstMeta or %NULL
* when there are no more items.
*/
GstMeta *
gst_buffer_iterate_meta (GstBuffer * buffer, gpointer * state)
{
GstMetaItem **meta;
g_return_val_if_fail (buffer != NULL, NULL);
g_return_val_if_fail (state != NULL, NULL);
meta = (GstMetaItem **) state;
if (*meta == NULL)
/* state NULL, move to first item */
*meta = GST_BUFFER_META (buffer);
else
/* state !NULL, move to next item in list */
*meta = (*meta)->next;
if (*meta)
return &(*meta)->meta;
else
return NULL;
}
/**
* gst_buffer_iterate_meta_filtered: (skip)
* @buffer: a #GstBuffer
* @state: (out caller-allocates): an opaque state pointer
* @meta_api_type: only return #GstMeta of this type
*
* Retrieves the next #GstMeta of type @meta_api_type after the current one
* according to @state. If @state points to %NULL, the first metadata of
* type @meta_api_type is returned.
*
* @state will be updated with an opaque state pointer
*
* Returns: (transfer none) (nullable): The next #GstMeta of type
* @meta_api_type or %NULL when there are no more items.
*
* Since: 1.12
*/
GstMeta *
gst_buffer_iterate_meta_filtered (GstBuffer * buffer, gpointer * state,
GType meta_api_type)
{
GstMetaItem **meta;
g_return_val_if_fail (buffer != NULL, NULL);
g_return_val_if_fail (state != NULL, NULL);
meta = (GstMetaItem **) state;
if (*meta == NULL)
/* state NULL, move to first item */
*meta = GST_BUFFER_META (buffer);
else
/* state !NULL, move to next item in list */
*meta = (*meta)->next;
while (*meta != NULL && (*meta)->meta.info->api != meta_api_type)
*meta = (*meta)->next;
if (*meta)
return &(*meta)->meta;
else
return NULL;
}
/**
* gst_buffer_foreach_meta:
* @buffer: a #GstBuffer
* @func: (scope call) (closure user_data): a #GstBufferForeachMetaFunc to call
* @user_data: user data passed to @func
*
* Calls @func with @user_data for each meta in @buffer.
*
* @func can modify the passed meta pointer or its contents. The return value
* of @func defines if this function returns or if the remaining metadata items
* in the buffer should be skipped.
*
* Returns: %FALSE when @func returned %FALSE for one of the metadata.
*/
gboolean
gst_buffer_foreach_meta (GstBuffer * buffer, GstBufferForeachMetaFunc func,
gpointer user_data)
{
GstMetaItem *walk, *prev, *next;
gboolean res = TRUE;
g_return_val_if_fail (buffer != NULL, FALSE);
g_return_val_if_fail (func != NULL, FALSE);
/* find the metadata and delete */
prev = GST_BUFFER_META (buffer);
for (walk = prev; walk; walk = next) {
GstMeta *m, *new;
m = new = &walk->meta;
next = walk->next;
res = func (buffer, &new, user_data);
if (new == NULL) {
const GstMetaInfo *info = m->info;
GST_CAT_DEBUG (GST_CAT_BUFFER, "remove metadata %p (%s)", m,
g_type_name (info->type));
g_return_val_if_fail (gst_buffer_is_writable (buffer), FALSE);
g_return_val_if_fail (!GST_META_FLAG_IS_SET (m, GST_META_FLAG_LOCKED),
FALSE);
if (GST_BUFFER_TAIL_META (buffer) == walk) {
if (prev != walk)
GST_BUFFER_TAIL_META (buffer) = prev;
else
GST_BUFFER_TAIL_META (buffer) = NULL;
}
/* remove from list */
if (GST_BUFFER_META (buffer) == walk)
prev = GST_BUFFER_META (buffer) = next;
else
prev->next = next;
/* call free_func if any */
if (info->free_func)
info->free_func (m, buffer);
/* and free the slice */
g_free (walk);
} else {
prev = walk;
}
if (!res)
break;
}
return res;
}
/**
* gst_buffer_extract_dup:
* @buffer: a #GstBuffer
* @offset: the offset to extract
* @size: the size to extract
* @dest: (array length=dest_size) (element-type guint8) (out): A pointer where
* the destination array will be written. Might be %NULL if the size is 0.
* @dest_size: (out): A location where the size of @dest can be written
*
* Extracts a copy of at most @size bytes the data at @offset into
* newly-allocated memory. @dest must be freed using g_free() when done.
*
* Since: 1.0.10
*/
void
gst_buffer_extract_dup (GstBuffer * buffer, gsize offset, gsize size,
gpointer * dest, gsize * dest_size)
{
gsize real_size, alloc_size;
real_size = gst_buffer_get_size (buffer);
alloc_size = MIN (real_size - offset, size);
if (alloc_size == 0) {
*dest = NULL;
*dest_size = 0;
} else {
*dest = g_malloc (alloc_size);
*dest_size = gst_buffer_extract (buffer, offset, *dest, size);
}
}
GST_DEBUG_CATEGORY_STATIC (gst_parent_buffer_meta_debug);
/**
* gst_buffer_add_parent_buffer_meta:
* @buffer: (transfer none): a #GstBuffer
* @ref: (transfer none): a #GstBuffer to ref
*
* Adds a #GstParentBufferMeta to @buffer that holds a reference on
* @ref until the buffer is freed.
*
* Returns: (transfer none) (nullable): The #GstParentBufferMeta that was added to the buffer
*
* Since: 1.6
*/
GstParentBufferMeta *
gst_buffer_add_parent_buffer_meta (GstBuffer * buffer, GstBuffer * ref)
{
GstParentBufferMeta *meta;
g_return_val_if_fail (GST_IS_BUFFER (ref), NULL);
meta =
(GstParentBufferMeta *) gst_buffer_add_meta (buffer,
GST_PARENT_BUFFER_META_INFO, NULL);
if (!meta)
return NULL;
meta->buffer = gst_buffer_ref (ref);
return meta;
}
static gboolean
_gst_parent_buffer_meta_transform (GstBuffer * dest, GstMeta * meta,
GstBuffer * buffer, GQuark type, gpointer data)
{
GstParentBufferMeta *dmeta, *smeta;
smeta = (GstParentBufferMeta *) meta;
if (GST_META_TRANSFORM_IS_COPY (type)) {
/* copy over the reference to the parent buffer.
* Usually, this meta means we need to keep the parent buffer
* alive because one of the child memories is in use, which
* might not be the case if memory is deep copied or sub-regioned,
* but we can't tell, so keep the meta */
dmeta = gst_buffer_add_parent_buffer_meta (dest, smeta->buffer);
if (!dmeta)
return FALSE;
GST_CAT_DEBUG (gst_parent_buffer_meta_debug,
"copy buffer reference metadata");
} else {
/* return FALSE, if transform type is not supported */
return FALSE;
}
return TRUE;
}
static void
_gst_parent_buffer_meta_free (GstParentBufferMeta * parent_meta,
GstBuffer * buffer)
{
GST_CAT_DEBUG (gst_parent_buffer_meta_debug,
"Dropping reference on buffer %p", parent_meta->buffer);
gst_buffer_unref (parent_meta->buffer);
}
static gboolean
_gst_parent_buffer_meta_init (GstParentBufferMeta * parent_meta,
gpointer params, GstBuffer * buffer)
{
static gsize _init;
if (g_once_init_enter (&_init)) {
GST_DEBUG_CATEGORY_INIT (gst_parent_buffer_meta_debug, "parentbuffermeta",
0, "parentbuffermeta");
g_once_init_leave (&_init, 1);
}
parent_meta->buffer = NULL;
return TRUE;
}
/**
* gst_parent_buffer_meta_api_get_type: (attributes doc.skip=true)
*/
GType
gst_parent_buffer_meta_api_get_type (void)
{
static GType type = 0;
static const gchar *tags[] = { GST_META_TAG_MEMORY_REFERENCE_STR, NULL };
if (g_once_init_enter (&type)) {
GType _type = gst_meta_api_type_register ("GstParentBufferMetaAPI", tags);
g_once_init_leave (&type, _type);
}
return type;
}
/**
* gst_parent_buffer_meta_get_info:
*
* Gets the global #GstMetaInfo describing the #GstParentBufferMeta meta.
*
* Returns: (transfer none): The #GstMetaInfo
*
* Since: 1.6
*/
const GstMetaInfo *
gst_parent_buffer_meta_get_info (void)
{
static const GstMetaInfo *meta_info = NULL;
if (g_once_init_enter ((GstMetaInfo **) & meta_info)) {
const GstMetaInfo *meta =
gst_meta_register (gst_parent_buffer_meta_api_get_type (),
"GstParentBufferMeta",
sizeof (GstParentBufferMeta),
(GstMetaInitFunction) _gst_parent_buffer_meta_init,
(GstMetaFreeFunction) _gst_parent_buffer_meta_free,
_gst_parent_buffer_meta_transform);
g_once_init_leave ((GstMetaInfo **) & meta_info, (GstMetaInfo *) meta);
}
return meta_info;
}
GST_DEBUG_CATEGORY_STATIC (gst_reference_timestamp_meta_debug);
/**
* gst_buffer_add_reference_timestamp_meta:
* @buffer: (transfer none): a #GstBuffer
* @reference: (transfer none): identifier for the timestamp reference.
* @timestamp: timestamp
* @duration: duration, or %GST_CLOCK_TIME_NONE
*
* Adds a #GstReferenceTimestampMeta to @buffer that holds a @timestamp and
* optionally @duration based on a specific timestamp @reference. See the
* documentation of #GstReferenceTimestampMeta for details.
*
* Returns: (transfer none) (nullable): The #GstReferenceTimestampMeta that was added to the buffer
*
* Since: 1.14
*/
GstReferenceTimestampMeta *
gst_buffer_add_reference_timestamp_meta (GstBuffer * buffer,
GstCaps * reference, GstClockTime timestamp, GstClockTime duration)
{
GstReferenceTimestampMeta *meta;
g_return_val_if_fail (GST_IS_CAPS (reference), NULL);
g_return_val_if_fail (timestamp != GST_CLOCK_TIME_NONE, NULL);
meta =
(GstReferenceTimestampMeta *) gst_buffer_add_meta (buffer,
GST_REFERENCE_TIMESTAMP_META_INFO, NULL);
if (!meta)
return NULL;
meta->reference = gst_caps_ref (reference);
meta->timestamp = timestamp;
meta->duration = duration;
return meta;
}
/**
* gst_buffer_get_reference_timestamp_meta:
* @buffer: a #GstBuffer
* @reference: (allow-none): a reference #GstCaps
*
* Finds the first #GstReferenceTimestampMeta on @buffer that conforms to
* @reference. Conformance is tested by checking if the meta's reference is a
* subset of @reference.
*
* Buffers can contain multiple #GstReferenceTimestampMeta metadata items.
*
* Returns: (transfer none) (nullable): the #GstReferenceTimestampMeta or %NULL when there
* is no such metadata on @buffer.
*
* Since: 1.14
*/
GstReferenceTimestampMeta *
gst_buffer_get_reference_timestamp_meta (GstBuffer * buffer,
GstCaps * reference)
{
gpointer state = NULL;
GstMeta *meta;
const GstMetaInfo *info = GST_REFERENCE_TIMESTAMP_META_INFO;
while ((meta = gst_buffer_iterate_meta (buffer, &state))) {
if (meta->info->api == info->api) {
GstReferenceTimestampMeta *rmeta = (GstReferenceTimestampMeta *) meta;
if (!reference)
return rmeta;
if (gst_caps_is_subset (rmeta->reference, reference))
return rmeta;
}
}
return NULL;
}
static gboolean
_gst_reference_timestamp_meta_transform (GstBuffer * dest, GstMeta * meta,
GstBuffer * buffer, GQuark type, gpointer data)
{
const GstReferenceTimestampMeta *smeta, *ometa;
GstReferenceTimestampMeta *dmeta;
gpointer iter = NULL;
/* we copy over the reference timestamp meta, independent of transformation
* that happens. If it applied to the original buffer, it still applies to
* the new buffer as it refers to the time when the media was captured */
smeta = (const GstReferenceTimestampMeta *) meta;
while ((ometa = (const GstReferenceTimestampMeta *)
gst_buffer_iterate_meta_filtered (dest, &iter,
GST_REFERENCE_TIMESTAMP_META_API_TYPE))) {
if (ometa->timestamp == smeta->timestamp
&& ometa->duration == smeta->duration
&& gst_caps_is_equal (ometa->reference, smeta->reference)) {
GST_CAT_TRACE (gst_reference_timestamp_meta_debug,
"Not copying reference timestamp metadata from buffer %p to %p because equal meta already exists",
buffer, dest);
return TRUE;
}
}
dmeta =
gst_buffer_add_reference_timestamp_meta (dest, smeta->reference,
smeta->timestamp, smeta->duration);
if (!dmeta)
return FALSE;
GST_CAT_DEBUG (gst_reference_timestamp_meta_debug,
"copy reference timestamp metadata from buffer %p to %p", buffer, dest);
return TRUE;
}
static void
_gst_reference_timestamp_meta_free (GstReferenceTimestampMeta * meta,
GstBuffer * buffer)
{
if (meta->reference)
gst_caps_unref (meta->reference);
}
static gboolean
_gst_reference_timestamp_meta_init (GstReferenceTimestampMeta * meta,
gpointer params, GstBuffer * buffer)
{
static gsize _init;
if (g_once_init_enter (&_init)) {
GST_DEBUG_CATEGORY_INIT (gst_reference_timestamp_meta_debug,
"referencetimestampmeta", 0, "referencetimestampmeta");
g_once_init_leave (&_init, 1);
}
meta->reference = NULL;
meta->timestamp = GST_CLOCK_TIME_NONE;
meta->duration = GST_CLOCK_TIME_NONE;
return TRUE;
}
/**
* gst_reference_timestamp_meta_api_get_type: (attributes doc.skip=true)
*/
GType
gst_reference_timestamp_meta_api_get_type (void)
{
static GType type = 0;
static const gchar *tags[] = { NULL };
if (g_once_init_enter (&type)) {
GType _type =
gst_meta_api_type_register ("GstReferenceTimestampMetaAPI", tags);
g_once_init_leave (&type, _type);
}
return type;
}
static gboolean
timestamp_meta_serialize (const GstMeta * meta, GstByteArrayInterface * data,
guint8 * version)
{
const GstReferenceTimestampMeta *rtmeta =
(const GstReferenceTimestampMeta *) meta;
gchar *caps_str = gst_caps_to_string (rtmeta->reference);
gsize caps_str_len = strlen (caps_str);
gsize size = 16 + caps_str_len + 1;
guint8 *ptr = gst_byte_array_interface_append (data, size);
if (ptr == NULL) {
g_free (caps_str);
return FALSE;
}
GST_WRITE_UINT64_LE (ptr, rtmeta->timestamp);
GST_WRITE_UINT64_LE (ptr + 8, rtmeta->duration);
memcpy (ptr + 16, caps_str, caps_str_len + 1);
g_free (caps_str);
return TRUE;
}
static GstMeta *
timestamp_meta_deserialize (const GstMetaInfo * info, GstBuffer * buffer,
const guint8 * data, gsize size, guint8 version)
{
/* Sanity check: caps_str must be 0-terminated. */
if (version != 0 || size < 2 * sizeof (guint64) + 1 || data[size - 1] != '\0')
return NULL;
guint64 timestamp = GST_READ_UINT64_LE (data);
guint64 duration = GST_READ_UINT64_LE (data + 8);
const gchar *caps_str = (const gchar *) data + 16;
GstCaps *reference = gst_caps_from_string (caps_str);
GstMeta *meta = (GstMeta *) gst_buffer_add_reference_timestamp_meta (buffer,
reference, timestamp, duration);
gst_caps_unref (reference);
return meta;
}
/**
* gst_reference_timestamp_meta_get_info:
*
* Gets the global #GstMetaInfo describing the #GstReferenceTimestampMeta meta.
*
* Returns: (transfer none): The #GstMetaInfo
*
* Since: 1.14
*/
const GstMetaInfo *
gst_reference_timestamp_meta_get_info (void)
{
static const GstMetaInfo *meta_info = NULL;
if (g_once_init_enter ((GstMetaInfo **) & meta_info)) {
const GstMetaInfo *meta = NULL;
GstMetaInfo *info =
gst_meta_info_new (gst_reference_timestamp_meta_api_get_type (),
"GstReferenceTimestampMeta",
sizeof (GstReferenceTimestampMeta));
info->init_func = (GstMetaInitFunction) _gst_reference_timestamp_meta_init;
info->free_func = (GstMetaFreeFunction) _gst_reference_timestamp_meta_free;
info->transform_func = _gst_reference_timestamp_meta_transform;
info->serialize_func = timestamp_meta_serialize;
info->deserialize_func = timestamp_meta_deserialize;
meta = gst_meta_info_register (info);
g_once_init_leave ((GstMetaInfo **) & meta_info, (GstMetaInfo *) meta);
}
return meta_info;
}
/**
* gst_buffer_add_custom_meta:
* @buffer: (transfer none): a #GstBuffer
* @name: the registered name of the desired custom meta
*
* Creates and adds a #GstCustomMeta for the desired @name. @name must have
* been successfully registered with gst_meta_register_custom().
*
* Returns: (transfer none) (nullable): The #GstCustomMeta that was added to the buffer
*
* Since: 1.20
*/
GstCustomMeta *
gst_buffer_add_custom_meta (GstBuffer * buffer, const gchar * name)
{
GstCustomMeta *meta;
const GstMetaInfo *info;
g_return_val_if_fail (name != NULL, NULL);
g_return_val_if_fail (GST_IS_BUFFER (buffer), NULL);
info = gst_meta_get_info (name);
if (info == NULL || !gst_meta_info_is_custom (info))
return NULL;
meta = (GstCustomMeta *) gst_buffer_add_meta (buffer, info, NULL);
return meta;
}
/**
* gst_buffer_get_custom_meta:
* @buffer: a #GstBuffer
* @name: the registered name of the custom meta to retrieve.
*
* Finds the first #GstCustomMeta on @buffer for the desired @name.
*
* Returns: (transfer none) (nullable): the #GstCustomMeta
*
* Since: 1.20
*/
GstCustomMeta *
gst_buffer_get_custom_meta (GstBuffer * buffer, const gchar * name)
{
const GstMetaInfo *info;
g_return_val_if_fail (buffer != NULL, NULL);
g_return_val_if_fail (name != NULL, NULL);
info = gst_meta_get_info (name);
if (!info)
return NULL;
if (!gst_meta_info_is_custom (info))
return NULL;
return (GstCustomMeta *) gst_buffer_get_meta (buffer, info->api);
}
/**
* gst_buffer_ref: (skip)
* @buf: a #GstBuffer.
*
* Increases the refcount of the given buffer by one.
*
* Note that the refcount affects the writability
* of @buf and its metadata, see gst_buffer_is_writable().
* It is important to note that keeping additional references to
* GstBuffer instances can potentially increase the number
* of `memcpy` operations in a pipeline.
*
* Returns: (transfer full): @buf
*/
GstBuffer *
gst_buffer_ref (GstBuffer * buf)
{
return (GstBuffer *) gst_mini_object_ref (GST_MINI_OBJECT_CAST (buf));
}
/**
* gst_buffer_unref: (skip)
* @buf: (transfer full): a #GstBuffer.
*
* Decreases the refcount of the buffer. If the refcount reaches 0, the buffer
* with the associated metadata and memory will be freed.
*/
void
gst_buffer_unref (GstBuffer * buf)
{
gst_mini_object_unref (GST_MINI_OBJECT_CAST (buf));
}
/**
* gst_clear_buffer: (skip)
* @buf_ptr: a pointer to a #GstBuffer reference
*
* Clears a reference to a #GstBuffer.
*
* @buf_ptr must not be %NULL.
*
* If the reference is %NULL then this function does nothing. Otherwise, the
* reference count of the buffer is decreased and the pointer is set to %NULL.
*
* Since: 1.16
*/
void
gst_clear_buffer (GstBuffer ** buf_ptr)
{
gst_clear_mini_object ((GstMiniObject **) buf_ptr);
}
/**
* gst_buffer_copy: (skip)
* @buf: a #GstBuffer.
*
* Creates a copy of the given buffer. This will only copy the buffer's
* data to a newly allocated memory if needed (if the type of memory
* requires it), otherwise the underlying data is just referenced.
* Check gst_buffer_copy_deep() if you want to force the data
* to be copied to newly allocated memory.
*
* Returns: (transfer full) (nullable): a new copy of @buf if the copy succeeded, %NULL otherwise.
*/
GstBuffer *
gst_buffer_copy (const GstBuffer * buf)
{
return GST_BUFFER (gst_mini_object_copy (GST_MINI_OBJECT_CONST_CAST (buf)));
}
/**
* gst_buffer_replace: (skip)
* @obuf: (inout) (transfer full) (nullable): pointer to a pointer to
* a #GstBuffer to be replaced.
* @nbuf: (transfer none) (allow-none): pointer to a #GstBuffer that will
* replace the buffer pointed to by @obuf.
*
* Modifies a pointer to a #GstBuffer to point to a different #GstBuffer. The
* modification is done atomically (so this is useful for ensuring thread safety
* in some cases), and the reference counts are updated appropriately (the old
* buffer is unreffed, the new is reffed).
*
* Either @nbuf or the #GstBuffer pointed to by @obuf may be %NULL.
*
* Returns: %TRUE when @obuf was different from @nbuf.
*/
gboolean
gst_buffer_replace (GstBuffer ** obuf, GstBuffer * nbuf)
{
return gst_mini_object_replace ((GstMiniObject **) obuf,
(GstMiniObject *) nbuf);
}