gstreamer/gst/gstbuffer.c
Wim Taymans 82c92a9c7c buffer: improve arg checking
Allow idx == 0 and length == -1 on empty buffers for the _range methods.
2012-04-12 11:53:00 +02:00

1743 lines
48 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., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
/**
* SECTION: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.
* <example>
* <title>Creating a buffer for a video frame</title>
* <programlisting>
* 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);
* ...
* </programlisting>
* </example>
*
* 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 preceeding 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 #GstBufferFlag 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.
*
* Last reviewed on 2012-03-28 (0.11.3)
*/
#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 "gstutils.h"
#include "gstversion.h"
GType _gst_buffer_type = 0;
typedef struct _GstMetaItem GstMetaItem;
struct _GstMetaItem
{
GstMetaItem *next;
GstMeta meta;
};
#define ITEM_SIZE(info) ((info)->size + sizeof (GstMetaItem))
#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)
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;
} GstBufferImpl;
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 *
_get_merged_memory (GstBuffer * buffer, guint idx, guint length)
{
GstMemory **mem, *result;
mem = GST_BUFFER_MEM_ARRAY (buffer);
if (G_UNLIKELY (length == 0)) {
result = NULL;
} else if (G_LIKELY (length == 1)) {
result = gst_memory_ref (mem[idx]);
} else {
GstMemory *parent = NULL;
gsize size, poffset = 0;
size = gst_buffer_get_size (buffer);
if (G_UNLIKELY (_is_span (mem + idx, length, &poffset, &parent))) {
if (parent->flags & GST_MEMORY_FLAG_NO_SHARE) {
GST_CAT_DEBUG (GST_CAT_PERFORMANCE, "copy for merge %p", parent);
result = gst_memory_copy (parent, poffset, size);
} else {
result = gst_memory_share (parent, poffset, size);
}
} else {
gsize i, tocopy, left;
GstMapInfo sinfo, dinfo;
guint8 *ptr;
result = gst_allocator_alloc (NULL, size, NULL);
gst_memory_map (result, &dinfo, GST_MAP_WRITE);
ptr = dinfo.data;
left = size;
for (i = idx; i < length && left > 0; i++) {
gst_memory_map (mem[i], &sinfo, GST_MAP_READ);
tocopy = MIN (sinfo.size, left);
GST_CAT_DEBUG (GST_CAT_PERFORMANCE,
"memcpy for merge %p from memory %p", 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 void
_replace_memory (GstBuffer * buffer, guint len, guint idx, guint length,
GstMemory * mem)
{
gsize end, i;
end = idx + length;
GST_LOG ("buffer %p replace %u-%" G_GSIZE_FORMAT " with memory %p", buffer,
idx, end, mem);
/* unref old memory */
for (i = idx; i < end; i++)
gst_memory_unref (GST_BUFFER_MEM_PTR (buffer, i));
if (mem != NULL) {
/* replace with single memory */
GST_BUFFER_MEM_PTR (buffer, idx) = mem;
idx++;
length--;
}
if (end < len) {
g_memmove (&GST_BUFFER_MEM_PTR (buffer, idx),
&GST_BUFFER_MEM_PTR (buffer, end), (len - end) * sizeof (gpointer));
}
GST_BUFFER_MEM_LEN (buffer) = len - length;
}
static inline void
_memory_add (GstBuffer * buffer, guint idx, GstMemory * mem)
{
guint i, len = GST_BUFFER_MEM_LEN (buffer);
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_DEFINE_MINI_OBJECT_TYPE (GstBuffer, gst_buffer);
void
_priv_gst_buffer_initialize (void)
{
_gst_buffer_type = gst_buffer_get_type ();
}
/**
* 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.
*/
void
gst_buffer_copy_into (GstBuffer * dest, GstBuffer * src,
GstBufferCopyFlags flags, gsize offset, gsize size)
{
GstMetaItem *walk;
gsize bufsize;
gboolean region = FALSE;
g_return_if_fail (dest != NULL);
g_return_if_fail (src != NULL);
/* nothing to copy if the buffers are the same */
if (G_UNLIKELY (dest == src))
return;
g_return_if_fail (gst_buffer_is_writable (dest));
bufsize = gst_buffer_get_size (src);
g_return_if_fail (bufsize >= offset);
if (offset > 0)
region = TRUE;
if (size == -1)
size = bufsize - offset;
if (size < bufsize)
region = TRUE;
g_return_if_fail (bufsize >= offset + size);
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 */
GST_MINI_OBJECT_FLAGS (dest) = GST_MINI_OBJECT_FLAGS (src);
}
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) {
GstMemory *mem;
gsize skip, left, len, i, bsize;
len = GST_BUFFER_MEM_LEN (src);
left = size;
skip = offset;
/* copy and make regions of the memory */
for (i = 0; i < len && left > 0; i++) {
mem = GST_BUFFER_MEM_PTR (src, i);
bsize = gst_memory_get_sizes (mem, NULL, NULL);
if (bsize <= skip) {
/* don't copy buffer */
skip -= bsize;
} else {
gsize tocopy;
tocopy = MIN (bsize - skip, left);
if (mem->flags & GST_MEMORY_FLAG_NO_SHARE) {
/* no share, always copy then */
mem = gst_memory_copy (mem, skip, tocopy);
skip = 0;
} else if (tocopy < bsize) {
/* we need to clip something */
mem = gst_memory_share (mem, skip, tocopy);
skip = 0;
} else {
mem = gst_memory_ref (mem);
}
_memory_add (dest, -1, mem);
left -= tocopy;
}
}
if (flags & GST_BUFFER_COPY_MERGE) {
len = GST_BUFFER_MEM_LEN (dest);
_replace_memory (dest, len, 0, len, _get_merged_memory (dest, 0, len));
}
}
if (flags & GST_BUFFER_COPY_META) {
for (walk = GST_BUFFER_META (src); walk; walk = walk->next) {
GstMeta *meta = &walk->meta;
const GstMetaInfo *info = meta->info;
if (info->transform_func) {
GstMetaTransformCopy copy_data;
copy_data.region = region;
copy_data.offset = offset;
copy_data.size = size;
info->transform_func (dest, meta, src,
_gst_meta_transform_copy, &copy_data);
}
}
}
}
static GstBuffer *
_gst_buffer_copy (GstBuffer * buffer)
{
GstBuffer *copy;
g_return_val_if_fail (buffer != NULL, NULL);
/* create a fresh new buffer */
copy = gst_buffer_new ();
/* we simply copy everything from our parent */
gst_buffer_copy_into (copy, buffer, GST_BUFFER_COPY_ALL, 0, -1);
return copy;
}
/* 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;
gsize msize;
g_return_if_fail (buffer != NULL);
GST_CAT_LOG (GST_CAT_BUFFER, "finalize %p", buffer);
/* 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_slice_free1 (ITEM_SIZE (info), walk);
}
/* get the size, when unreffing the memory, we could also unref the buffer
* itself */
msize = GST_MINI_OBJECT_SIZE (buffer);
/* free our memory */
len = GST_BUFFER_MEM_LEN (buffer);
for (i = 0; i < len; i++)
gst_memory_unref (GST_BUFFER_MEM_PTR (buffer, i));
/* we set msize to 0 when the buffer is part of the memory block */
if (msize)
g_slice_free1 (msize, buffer);
else
gst_memory_unref (GST_BUFFER_BUFMEM (buffer));
}
static void
gst_buffer_init (GstBufferImpl * buffer, gsize size)
{
gst_mini_object_init (GST_MINI_OBJECT_CAST (buffer), _gst_buffer_type, size);
buffer->buffer.mini_object.copy =
(GstMiniObjectCopyFunction) _gst_buffer_copy;
buffer->buffer.mini_object.dispose =
(GstMiniObjectDisposeFunction) _gst_buffer_dispose;
buffer->buffer.mini_object.free =
(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.
*
* MT safe.
*
* Returns: (transfer full): the new #GstBuffer.
*/
GstBuffer *
gst_buffer_new (void)
{
GstBufferImpl *newbuf;
newbuf = g_slice_new (GstBufferImpl);
GST_CAT_LOG (GST_CAT_BUFFER, "new %p", newbuf);
gst_buffer_init (newbuf, sizeof (GstBufferImpl));
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.
*
* MT safe.
*
* Returns: (transfer full): a new #GstBuffer, or NULL if the memory couldn't
* be allocated.
*/
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)
_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_slice_alloc (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);
}
#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));
#endif
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: data to wrap
* @maxsize: allocated size of @data
* @offset: offset in @data
* @size: size of valid data
* @user_data: user_data
* @notify: called with @user_data when the memory is freed
*
* Allocate 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)
{
GstBuffer *newbuf;
newbuf = gst_buffer_new ();
gst_buffer_append_memory (newbuf,
gst_memory_new_wrapped (flags, data, maxsize, offset, size,
user_data, notify));
return newbuf;
}
/**
* gst_buffer_new_wrapped:
* @data: 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.
*
* MT safe.
*
* 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_n_memory:
* @buffer: a #GstBuffer.
*
* Get the amount of memory blocks that this buffer has.
*
* Returns: (transfer full): the amount of memory block in this buffer.
*/
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_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.
*
* Insert the memory block @mem to @buffer at @idx. This function takes ownership
* of @mem and thus doesn't increase its refcount.
*/
void
gst_buffer_insert_memory (GstBuffer * buffer, gint idx, GstMemory * mem)
{
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)));
_memory_add (buffer, idx, mem);
}
static GstMemory *
_get_mapped (GstBuffer * buffer, guint idx, GstMapInfo * info,
GstMapFlags flags)
{
GstMemory *mem, *mapped;
mem = GST_BUFFER_MEM_PTR (buffer, idx);
mapped = gst_memory_make_mapped (mem, info, flags);
if (!mapped)
return NULL;
if (mapped != mem) {
GST_BUFFER_MEM_PTR (buffer, idx) = mapped;
gst_memory_unref (mem);
mem = mapped;
}
return mem;
}
/**
* gst_buffer_peek_memory:
* @buffer: a #GstBuffer.
* @idx: an index
*
* Get 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.
*
* Since this call does not influence the refcount of the memory,
* gst_memory_is_exclusive() can be used to check if @buffer is the sole owner
* of the returned memory.
*
* Returns: (transfer none): the #GstMemory at @idx.
*/
GstMemory *
gst_buffer_peek_memory (GstBuffer * buffer, guint idx)
{
guint len;
g_return_val_if_fail (GST_IS_BUFFER (buffer), NULL);
len = GST_BUFFER_MEM_LEN (buffer);
g_return_val_if_fail (idx < len, NULL);
return GST_BUFFER_MEM_PTR (buffer, idx);
}
/**
* gst_buffer_get_memory_range:
* @buffer: a #GstBuffer.
* @idx: an index
* @length: a length
*
* Get @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): a #GstMemory that contains the merged data of @length
* blocks starting at @idx. Use gst_memory_unref () after usage.
*/
GstMemory *
gst_buffer_get_memory_range (GstBuffer * buffer, guint idx, gint length)
{
guint len;
GST_DEBUG ("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_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));
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_range:
* @buffer: a #GstBuffer.
* @idx: an index
* @length: a length
*
* Remove @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));
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
*
* Find 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 bock 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 bock 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 = gst_memory_get_sizes (mem, NULL, NULL);
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_get_sizes_range:
* @buffer: a #GstBuffer.
* @idx: an index
* @length: a length
* @offset: a pointer to the offset
* @maxsize: a pointer to the maxsize
*
* Get 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 @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 {
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_range:
* @buffer: a #GstBuffer.
* @idx: an index
* @length: a length
* @offset: the offset adjustement
* @size: the new size or -1 to just adjust the offset
*
* Set the total size of the @length memory blocks starting at @idx in
* @buffer
*/
void
gst_buffer_resize_range (GstBuffer * buffer, guint idx, gint length,
gssize offset, gssize size)
{
guint i, len, end;
gsize bsize, bufsize, bufoffs, bufmax;
GstMemory *mem;
g_return_if_fail (gst_buffer_is_writable (buffer));
g_return_if_fail (size >= -1);
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;
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_if_fail ((offset < 0 && bufoffs >= -offset) || (offset >= 0
&& bufoffs + offset <= bufmax));
if (size == -1) {
g_return_if_fail (bufsize >= offset);
size = bufsize - offset;
}
g_return_if_fail (bufmax >= bufoffs + offset + size);
/* no change */
if (offset == 0 && size == bufsize)
return;
end = idx + length;
/* copy and trim */
for (i = idx; i < end; i++) {
gsize left, noffs;
mem = GST_BUFFER_MEM_PTR (buffer, i);
bsize = gst_memory_get_sizes (mem, NULL, NULL);
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_exclusive (mem)) {
gst_memory_resize (mem, offset, left);
} else {
GstMemory *tmp;
if (mem->flags & GST_MEMORY_FLAG_NO_SHARE)
tmp = gst_memory_copy (mem, offset, left);
else
tmp = gst_memory_share (mem, offset, left);
gst_memory_unref (mem);
mem = tmp;
}
}
offset = noffs;
size -= left;
GST_BUFFER_MEM_PTR (buffer, i) = mem;
}
}
/**
* gst_buffer_map_range:
* @buffer: a #GstBuffer.
* @idx: an index
* @length: a length
* @info: (out): info about the mapping
* @flags: flags for the mapping
*
* This function 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: (transfer full): %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);
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_OBJECT (buffer, "write map requested on non-writable buffer");
g_critical ("write map requested on non-writable buffer");
return FALSE;
}
no_memory:
{
/* empty buffer, we need to return NULL */
GST_DEBUG_OBJECT (buffer, "can't get buffer memory");
info->memory = NULL;
info->data = NULL;
info->size = 0;
info->maxsize = 0;
return TRUE;
}
cannot_map:
{
GST_DEBUG_OBJECT (buffer, "cannot map memory");
return FALSE;
}
}
/**
* gst_buffer_unmap:
* @buffer: a #GstBuffer.
* @info: a #GstMapInfo
*
* Release 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);
/* we need to check for NULL, it is possible that we tried to map a buffer
* without memory and we should be able to unmap that fine */
if (G_LIKELY (info->memory)) {
gst_memory_unmap (info->memory, info);
gst_memory_unref (info->memory);
}
}
/**
* gst_buffer_fill:
* @buffer: a #GstBuffer.
* @offset: the offset to fill
* @src: the source address
* @size: the size to fill
*
* Copy @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, 0);
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: the destination address
* @size: the size to extract
*
* Copy @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);
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: the memory to compare
* @size: the size to compare
*
* Compare @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);
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
*
* Fill @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);
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.
*
* 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.
*
* MT safe.
*
* Returns: (transfer full): the new #GstBuffer or NULL if the arguments were
* invalid.
*/
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);
gst_buffer_copy_into (copy, buffer, flags, offset, size);
return copy;
}
/**
* gst_buffer_append:
* @buf1: (transfer full): the first source #GstBuffer to append.
* @buf2: (transfer full): the second source #GstBuffer to append.
*
* Append 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)
{
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);
len = GST_BUFFER_MEM_LEN (buf2);
for (i = 0; i < len; i++) {
GstMemory *mem;
mem = GST_BUFFER_MEM_PTR (buf2, i);
GST_BUFFER_MEM_PTR (buf2, i) = NULL;
_memory_add (buf1, -1, mem);
}
/* we can calculate the duration too. Also make sure we're not messing
* with invalid DURATIONS */
if (GST_BUFFER_DURATION_IS_VALID (buf1) &&
GST_BUFFER_DURATION_IS_VALID (buf2)) {
/* add duration */
GST_BUFFER_DURATION (buf1) += GST_BUFFER_DURATION (buf2);
}
if (GST_BUFFER_OFFSET_END_IS_VALID (buf2)) {
/* set offset_end */
GST_BUFFER_OFFSET_END (buf1) = GST_BUFFER_OFFSET_END (buf2);
}
GST_BUFFER_MEM_LEN (buf2) = 0;
gst_buffer_unref (buf2);
return buf1;
}
/**
* gst_buffer_get_meta:
* @buffer: a #GstBuffer
* @api: the #GType of an API
*
* Get the metadata for @api on buffer. When there is no such
* metadata, NULL is returned.
*
* Returns: 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_add_meta:
* @buffer: a #GstBuffer
* @info: a #GstMetaInfo
* @params: params for @info
*
* Add metadata for @info to @buffer using the parameters in @params.
*
* Returns: (transfer none): 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);
item = g_slice_alloc (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;
/* and add to the list of metadata */
item->next = GST_BUFFER_META (buffer);
GST_BUFFER_META (buffer) = item;
return result;
init_failed:
{
g_slice_free1 (size, item);
return NULL;
}
}
/**
* gst_buffer_remove_meta:
* @buffer: a #GstBuffer
* @meta: a #GstMeta
*
* Remove 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);
/* 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_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_slice_free1 (ITEM_SIZE (info), walk);
break;
}
prev = walk;
}
return walk != NULL;
}
/**
* gst_buffer_iterate_meta:
* @buffer: a #GstBuffer
* @state: an opaque state pointer
*
* Retrieve the next #GstMeta after @current. If @state points
* to %NULL, the first metadata is returned.
*
* @state will be updated with an opage state pointer
*
* Returns: 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_foreach_meta:
* @buffer: a #GstBuffer
* @func: (scope call): a #GstBufferForeachMetaFunc to call
* @user_data: (closure): user data passed to @func
*
* Call @func with @user_data for each meta in @buffer.
*
* @func can modify the passed meta pointer or its contents. The return value
* of @func define if this function returns or if the remaining metadata items
* in the buffer should be skipped.
*/
void
gst_buffer_foreach_meta (GstBuffer * buffer, GstBufferForeachMetaFunc func,
gpointer user_data)
{
GstMetaItem *walk, *prev, *next;
g_return_if_fail (buffer != NULL);
g_return_if_fail (func != NULL);
/* find the metadata and delete */
prev = GST_BUFFER_META (buffer);
for (walk = prev; walk; walk = next) {
GstMeta *m, *new;
gboolean res;
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_if_fail (gst_buffer_is_writable (buffer));
/* remove from list */
if (GST_BUFFER_META (buffer) == walk)
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_slice_free1 (ITEM_SIZE (info), walk);
}
if (!res)
break;
}
}