gstreamer/gst/gstbuffer.c
Thomas Vander Stichele 56c8649f39 doc updates
Original commit message from CVS:
doc updates
2002-08-30 14:54:58 +00:00

521 lines
15 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.
*/
/* this file makes too much noise for most debugging sessions */
#define GST_DEBUG_FORCE_DISABLE
#include "gst_private.h"
#include "gstdata_private.h"
#include "gstbuffer.h"
#include "gstmemchunk.h"
#include "gstlog.h"
#include "gstbufferpool-default.h"
GType _gst_buffer_type;
GType _gst_buffer_pool_type;
static gint _gst_buffer_live;
static gint _gst_buffer_pool_live;
static GstMemChunk *chunk;
void
_gst_buffer_initialize (void)
{
_gst_buffer_type = g_boxed_type_register_static ("GstBuffer",
(GBoxedCopyFunc) gst_data_ref,
(GBoxedFreeFunc) gst_data_unref);
_gst_buffer_pool_type = g_boxed_type_register_static ("GstBufferPool",
(GBoxedCopyFunc) gst_data_ref,
(GBoxedFreeFunc) gst_data_unref);
_gst_buffer_live = 0;
_gst_buffer_pool_live = 0;
chunk = gst_mem_chunk_new ("GstBufferChunk", sizeof (GstBuffer),
sizeof (GstBuffer) * 200, 0);
GST_INFO (GST_CAT_BUFFER, "Buffers are initialized now");
}
/**
* gst_buffer_print_stats:
*
* Logs statistics about live buffers (using g_log).
*/
void
gst_buffer_print_stats (void)
{
g_log (g_log_domain_gstreamer, G_LOG_LEVEL_INFO, "%d live buffer(s)",
_gst_buffer_live);
g_log (g_log_domain_gstreamer, G_LOG_LEVEL_INFO, "%d live bufferpool(s)",
_gst_buffer_pool_live);
}
static void
_gst_buffer_free_to_pool (GstBuffer *buffer)
{
GstBufferPool *pool = buffer->pool;
pool->buffer_free (pool, buffer, pool->user_data);
gst_data_unref (GST_DATA (pool));
}
static void
_gst_buffer_sub_free (GstBuffer *buffer)
{
gst_data_unref (GST_DATA (buffer->pool_private));
GST_BUFFER_DATA (buffer) = NULL;
GST_BUFFER_SIZE (buffer) = 0;
_GST_DATA_DISPOSE (GST_DATA (buffer));
gst_mem_chunk_free (chunk, GST_DATA (buffer));
_gst_buffer_live--;
}
/**
* gst_buffer_default_free:
* @buffer: a #GstBuffer to free.
*
* Frees the memory associated with the buffer including the buffer data,
* unless the GST_BUFFER_DONTFREE flags was set or the buffer data is NULL.
* This function is used by buffer pools.
*/
void
gst_buffer_default_free (GstBuffer *buffer)
{
/* free our data */
if (!GST_BUFFER_FLAG_IS_SET (buffer, GST_BUFFER_DONTFREE) && GST_BUFFER_DATA (buffer))
g_free (GST_BUFFER_DATA (buffer));
/* set to safe values */
GST_BUFFER_DATA (buffer) = NULL;
GST_BUFFER_SIZE (buffer) = 0;
_GST_DATA_DISPOSE (GST_DATA (buffer));
gst_mem_chunk_free (chunk, GST_DATA (buffer));
_gst_buffer_live--;
}
static GstBuffer*
_gst_buffer_copy_from_pool (GstBuffer *buffer)
{
return buffer->pool->buffer_copy (buffer->pool, buffer, buffer->pool->user_data);
}
/**
* gst_buffer_default_copy:
* @buffer: a #GstBuffer to make a copy of.
*
* Make a full newly allocated copy of the given buffer, data and all.
* This function is used by buffer pools.
*
* Returns: the new #GstBuffer.
*/
GstBuffer*
gst_buffer_default_copy (GstBuffer *buffer)
{
GstBuffer *copy;
/* create a fresh new buffer */
copy = gst_buffer_new ();
/* we simply copy everything from our parent */
GST_BUFFER_DATA (copy) = g_memdup (GST_BUFFER_DATA (buffer),
GST_BUFFER_SIZE (buffer));
GST_BUFFER_SIZE (copy) = GST_BUFFER_SIZE (buffer);
GST_BUFFER_MAXSIZE (copy) = GST_BUFFER_MAXSIZE (buffer);
GST_BUFFER_TIMESTAMP (copy) = GST_BUFFER_TIMESTAMP (buffer);
GST_BUFFER_OFFSET (copy) = GST_BUFFER_OFFSET (buffer);
return copy;
}
/**
* gst_buffer_new:
*
* Creates a newly allocated buffer without any data.
*
* Returns: the new #GstBuffer.
*/
GstBuffer*
gst_buffer_new (void)
{
GstBuffer *new;
new = gst_mem_chunk_alloc0 (chunk);
_gst_buffer_live++;
_GST_DATA_INIT (GST_DATA (new),
_gst_buffer_type,
0,
(GstDataFreeFunction) gst_buffer_default_free,
(GstDataCopyFunction) gst_buffer_default_copy);
GST_BUFFER_BUFFERPOOL (new) = NULL;
GST_BUFFER_POOL_PRIVATE (new) = NULL;
return new;
}
/**
* gst_buffer_new_and_alloc:
* @size: the size of the new buffer's data.
*
* Creates a newly allocated buffer with data of the given size.
*
* Returns: the new #GstBuffer.
*/
GstBuffer*
gst_buffer_new_and_alloc (guint size)
{
GstBuffer *new;
new = gst_buffer_new ();
GST_BUFFER_DATA (new) = g_malloc (size);
GST_BUFFER_SIZE (new) = size;
return new;
}
/**
* gst_buffer_new_from_pool:
* @pool: a #GstBufferPool to use.
* @offset: the offset of the new buffer.
* @size: the size of the new buffer.
*
* Creates a newly allocated buffer using the specified buffer pool,
* offset and size.
*
* Returns: the new #GstBuffer, or NULL if there was an error.
*/
GstBuffer*
gst_buffer_new_from_pool (GstBufferPool *pool, guint64 offset, guint size)
{
GstBuffer *buffer;
g_return_val_if_fail (pool != NULL, NULL);
buffer = pool->buffer_new (pool, offset, size, pool->user_data);
if (!buffer)
return NULL;
GST_BUFFER_BUFFERPOOL (buffer) = pool;
gst_data_ref (GST_DATA (pool));
/* override the buffer refcount functions with those from the pool (if any) */
if (pool->buffer_free)
GST_DATA (buffer)->free = (GstDataFreeFunction)_gst_buffer_free_to_pool;
if (pool->buffer_copy)
GST_DATA (buffer)->copy = (GstDataCopyFunction)_gst_buffer_copy_from_pool;
return buffer;
}
/**
* gst_buffer_create_sub:
* @parent: a parent #GstBuffer to create a subbuffer from.
* @offset: the offset into parent #GstBuffer.
* @size: the size of the new #GstBuffer sub-buffer (with size > 0).
*
* Creates a sub-buffer from the parent at a given offset.
* This sub-buffer uses the actual memory space of the parent buffer.
*
* Returns: the new #GstBuffer, or NULL if there was an error.
*/
GstBuffer*
gst_buffer_create_sub (GstBuffer *parent, guint offset, guint size)
{
GstBuffer *buffer;
gpointer buffer_data;
guint64 parent_offset;
g_return_val_if_fail (parent != NULL, NULL);
g_return_val_if_fail (GST_BUFFER_REFCOUNT_VALUE (parent) > 0, NULL);
g_return_val_if_fail (size > 0, NULL);
g_return_val_if_fail (parent->size >= offset + size, NULL);
/* remember the data for the new buffer */
buffer_data = parent->data + offset;
parent_offset = GST_BUFFER_OFFSET (parent);
/* make sure we're child not child from a child buffer */
while (GST_BUFFER_FLAG_IS_SET (parent, GST_BUFFER_SUBBUFFER)) {
parent = GST_BUFFER (parent->pool_private);
}
/* ref the real parent */
gst_data_ref (GST_DATA (parent));
/* make sure nobody overwrites data in the parent */
if (!GST_DATA_IS_READONLY (parent))
GST_DATA_FLAG_SET(parent, GST_DATA_READONLY);
/* create the new buffer */
buffer = gst_mem_chunk_alloc0 (chunk);
_gst_buffer_live++;
/* make sure nobody overwrites data in the new buffer
* by setting the READONLY flag */
_GST_DATA_INIT (GST_DATA (buffer),
_gst_buffer_type,
GST_DATA_FLAG_SHIFT (GST_BUFFER_SUBBUFFER) |
GST_DATA_FLAG_SHIFT (GST_DATA_READONLY),
(GstDataFreeFunction) _gst_buffer_sub_free,
(GstDataCopyFunction) gst_buffer_default_copy);
GST_BUFFER_OFFSET (buffer) = parent_offset + offset;
GST_BUFFER_TIMESTAMP (buffer) = -1;
GST_BUFFER_BUFFERPOOL (buffer) = NULL;
GST_BUFFER_POOL_PRIVATE (buffer) = parent;
/* set the right values in the child */
buffer->data = buffer_data;
buffer->size = size;
return buffer;
}
/**
* gst_buffer_merge:
* @buf1: a first source #GstBuffer to merge.
* @buf2: the second source #GstBuffer to merge.
*
* Create a new buffer that is the concatenation of the two source
* buffers. The original source buffers will not be modified or
* unref'd.
*
* Internally is nothing more than a specialized gst_buffer_span(),
* so the same optimizations can occur.
*
* Returns: the new #GstBuffer that's the concatenation of the source buffers.
*/
GstBuffer*
gst_buffer_merge (GstBuffer *buf1, GstBuffer *buf2)
{
GstBuffer *result;
/* we're just a specific case of the more general gst_buffer_span() */
result = gst_buffer_span (buf1, 0, buf2, buf1->size + buf2->size);
return result;
}
/**
* gst_buffer_is_span_fast:
* @buf1: a first source #GstBuffer.
* @buf2: the second source #GstBuffer.
*
* Determines whether a gst_buffer_span() is free (as in free beer),
* or requires a memcpy.
*
* Returns: TRUE if the buffers are contiguous,
* FALSE if a copy would be required.
*/
gboolean
gst_buffer_is_span_fast (GstBuffer *buf1, GstBuffer *buf2)
{
g_return_val_if_fail (GST_BUFFER_REFCOUNT_VALUE (buf1) > 0, FALSE);
g_return_val_if_fail (GST_BUFFER_REFCOUNT_VALUE (buf2) > 0, FALSE);
/* it's only fast if we have subbuffers of the same parent */
return ((GST_BUFFER_FLAG_IS_SET (buf1, GST_BUFFER_SUBBUFFER)) &&
(GST_BUFFER_FLAG_IS_SET (buf2, GST_BUFFER_SUBBUFFER)) &&
(buf1->pool_private == buf2->pool_private) &&
((buf1->data + buf1->size) == buf2->data));
}
/**
* gst_buffer_span:
* @buf1: a first source #GstBuffer to merge.
* @offset: the offset in the first buffer from where the new
* buffer should start.
* @buf2: the second source #GstBuffer to merge.
* @len: the total length of the new buffer.
*
* Creates a new buffer that consists of part of buf1 and buf2.
* Logically, buf1 and buf2 are concatenated into a single larger
* buffer, and a new buffer is created at the given offset inside
* this space, with a given length.
*
* If the two source buffers are children of the same larger buffer,
* and are contiguous, the new buffer will be a child of the shared
* parent, and thus no copying is necessary. you can use
* gst_buffer_is_span_fast() to determine if a memcpy will be needed.
*
* Returns: the new #GstBuffer that spans the two source buffers.
*/
GstBuffer*
gst_buffer_span (GstBuffer *buf1, guint32 offset, GstBuffer *buf2, guint32 len)
{
GstBuffer *newbuf;
g_return_val_if_fail (GST_BUFFER_REFCOUNT_VALUE (buf1) > 0, NULL);
g_return_val_if_fail (GST_BUFFER_REFCOUNT_VALUE (buf2) > 0, NULL);
g_return_val_if_fail (len > 0, NULL);
/* if the two buffers have the same parent and are adjacent */
if (gst_buffer_is_span_fast (buf1, buf2)) {
GstBuffer *parent = GST_BUFFER (buf1->pool_private);
/* we simply create a subbuffer of the common parent */
newbuf = gst_buffer_create_sub (parent,
buf1->data - parent->data + offset, len);
}
else {
GST_DEBUG (GST_CAT_BUFFER,
"slow path taken while spanning buffers %p and %p",
buffer, append);
/* otherwise we simply have to brute-force copy the buffers */
newbuf = gst_buffer_new_and_alloc (len);
/* copy relevant stuff from data struct of buffer1 */
GST_BUFFER_OFFSET (newbuf) = GST_BUFFER_OFFSET (buf1) + offset;
/* copy the first buffer's data across */
memcpy (newbuf->data, buf1->data + offset, buf1->size - offset);
/* copy the second buffer's data across */
memcpy (newbuf->data + (buf1->size - offset), buf2->data,
len - (buf1->size - offset));
}
/* if the offset is 0, the new buffer has the same timestamp as buf1 */
if (offset == 0)
GST_BUFFER_TIMESTAMP (newbuf) = GST_BUFFER_TIMESTAMP (buf1);
return newbuf;
}
void
gst_buffer_pool_default_free (GstBufferPool *pool)
{
_GST_DATA_DISPOSE (GST_DATA (pool));
g_free (pool);
_gst_buffer_pool_live--;
}
/**
* gst_buffer_pool_new:
* @free: the #GstDataFreeFunction to free the buffer pool.
* @copy: the #GstDataCopyFunction to copy the buffer pool.
* @buffer_new: the #GstBufferPoolBufferNewFunction to create a new buffer
* from this pool
* @buffer_copy: the #GstBufferPoolBufferCopyFunction to copy a buffer
* from this pool
* @buffer_free: the #GstBufferPoolBufferFreeFunction to free a buffer
* in this pool
* @user_data: the user data gpointer passed to buffer_* functions.
*
* Creates a new buffer pool with the given functions.
*
* Returns: a new #GstBufferPool, or NULL on error.
*/
GstBufferPool*
gst_buffer_pool_new (GstDataFreeFunction free,
GstDataCopyFunction copy,
GstBufferPoolBufferNewFunction buffer_new,
GstBufferPoolBufferCopyFunction buffer_copy,
GstBufferPoolBufferFreeFunction buffer_free,
gpointer user_data)
{
GstBufferPool *pool;
/* we need at least a buffer_new function */
g_return_val_if_fail (buffer_new != NULL, NULL);
pool = g_new0 (GstBufferPool, 1);
_gst_buffer_pool_live++;
GST_DEBUG (GST_CAT_BUFFER, "allocating new buffer pool %p\n", pool);
/* init data struct */
_GST_DATA_INIT (GST_DATA (pool),
_gst_buffer_pool_type,
0,
(free ? free : (GstDataFreeFunction) gst_buffer_pool_default_free),
copy);
/* set functions */
pool->buffer_new = buffer_new;
pool->buffer_copy = buffer_copy;
pool->buffer_free = buffer_free;
pool->user_data = user_data;
return pool;
}
/**
* gst_buffer_pool_is_active:
* @pool: the #GstBufferPool to query.
*
* Queries if the given buffer pool is active.
*
* Returns: TRUE if the pool is active.
*/
gboolean
gst_buffer_pool_is_active (GstBufferPool *pool)
{
return pool->active;
}
/**
* gst_buffer_pool_set_active:
* @pool: a #GstBufferPool to set the activity status on.
* @active: the new status of the pool.
*
* Sets the given pool to the active or inactive state depending on the
* active parameter.
*/
void
gst_buffer_pool_set_active (GstBufferPool *pool, gboolean active)
{
pool->active = active;
}
/**
* gst_buffer_pool_set_user_data:
* @pool: the #GstBufferPool to set the user data for.
* @user_data: the user_data to set on the buffer pool.
*
* Sets the given user data on the buffer pool.
*/
void
gst_buffer_pool_set_user_data (GstBufferPool *pool, gpointer user_data)
{
pool->user_data = user_data;
}
/**
* gst_buffer_pool_get_user_data:
* @pool: the #GstBufferPool to get the user data for.
*
* Gets the user data of the buffer pool.
*
* Returns: the user data associated with this buffer pool.
*/
gpointer
gst_buffer_pool_get_user_data (GstBufferPool *pool)
{
return pool->user_data;
}