gstreamer/gst/gstbuffer.c
Thomas Vander Stichele 0e140428ed more doc fixes
Original commit message from CVS:
more doc fixes
2002-04-17 15:19:56 +00:00

555 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 "gstbuffer.h"
GType _gst_buffer_type;
static GMemChunk *_gst_buffer_chunk;
static GMutex *_gst_buffer_chunk_lock;
static gint _gst_buffer_live;
void
_gst_buffer_initialize (void)
{
int buffersize = sizeof(GstBuffer);
static const GTypeInfo buffer_info = {
0, /* sizeof(class), */
NULL,
NULL,
NULL,
NULL,
NULL,
0, /* sizeof(object), */
0,
NULL,
NULL,
};
/* round up to the nearest 32 bytes for cache-line and other efficiencies */
buffersize = (((buffersize-1) / 32) + 1) * 32;
_gst_buffer_chunk = g_mem_chunk_new ("GstBuffer", buffersize,
buffersize * 32, G_ALLOC_AND_FREE);
_gst_buffer_chunk_lock = g_mutex_new ();
_gst_buffer_type = g_type_register_static (G_TYPE_INT, "GstBuffer", &buffer_info, 0);
_gst_buffer_live = 0;
}
/**
* 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 buffers", _gst_buffer_live);
}
/**
* gst_buffer_new:
*
* Creates a newly allocated buffer.
*
* Returns: new #GstBuffer
*/
GstBuffer*
gst_buffer_new (void)
{
GstBuffer *buffer;
g_mutex_lock (_gst_buffer_chunk_lock);
buffer = g_mem_chunk_alloc (_gst_buffer_chunk);
_gst_buffer_live++;
g_mutex_unlock (_gst_buffer_chunk_lock);
GST_INFO (GST_CAT_BUFFER,"creating new buffer %p",buffer);
GST_DATA_TYPE(buffer) = _gst_buffer_type;
buffer->lock = g_mutex_new ();
#ifdef HAVE_ATOMIC_H
atomic_set (&buffer->refcount, 1);
#else
buffer->refcount = 1;
#endif
buffer->flags = 0;
buffer->data = NULL;
buffer->size = 0;
buffer->maxsize = 0;
buffer->offset = -1;
buffer->timestamp = 0;
buffer->parent = NULL;
buffer->pool = NULL;
buffer->pool_private = NULL;
buffer->free = NULL;
buffer->copy = NULL;
return buffer;
}
/**
* gst_buffer_new_from_pool:
* @pool: the buffer pool to use
* @offset: the offset of the new buffer
* @size: the size of the new buffer
*
* Creates a newly allocated buffer using the specified bufferpool, offset and size.
*
* Returns: new #GstBuffer
*/
GstBuffer*
gst_buffer_new_from_pool (GstBufferPool *pool, guint32 offset, guint32 size)
{
GstBuffer *buffer;
g_return_val_if_fail (pool != NULL, NULL);
g_return_val_if_fail (pool->buffer_new != NULL, NULL);
buffer = pool->buffer_new (pool, offset, size, pool->user_data);
buffer->pool = pool;
buffer->free = pool->buffer_free;
buffer->copy = pool->buffer_copy;
GST_INFO (GST_CAT_BUFFER,"creating new buffer %p from pool %p (size %x, offset %x)",
buffer, pool, size, offset);
return buffer;
}
/**
* gst_buffer_create_sub:
* @parent: parent #GstBuffer
* @offset: offset into parent #GstBuffer
* @size: size of new sub-buffer
*
* Creates a sub-buffer from the parent at a given offset.
* This sub-buffer uses the actual memory space of the parent buffer.
*
* Returns: a new #GstBuffer
*/
GstBuffer*
gst_buffer_create_sub (GstBuffer *parent,
guint32 offset,
guint32 size)
{
GstBuffer *buffer;
g_return_val_if_fail (parent != NULL, NULL);
g_return_val_if_fail (GST_BUFFER_REFCOUNT(parent) > 0, NULL);
g_return_val_if_fail (size > 0, NULL);
g_return_val_if_fail ((offset+size) <= parent->size, NULL);
g_mutex_lock (_gst_buffer_chunk_lock);
buffer = g_mem_chunk_alloc (_gst_buffer_chunk);
_gst_buffer_live++;
g_mutex_unlock (_gst_buffer_chunk_lock);
GST_INFO (GST_CAT_BUFFER,"creating new subbuffer %p from parent %p (size %u, offset %u)",
buffer, parent, size, offset);
GST_DATA_TYPE(buffer) = _gst_buffer_type;
buffer->lock = g_mutex_new ();
#ifdef HAVE_ATOMIC_H
atomic_set (&buffer->refcount, 1);
#else
buffer->refcount = 1;
#endif
/* copy flags and type from parent, for lack of better */
buffer->flags = parent->flags;
/* set the data pointer, size, offset, and maxsize */
buffer->data = parent->data + offset;
buffer->size = size;
buffer->maxsize = parent->size - offset;
/* deal with bogus/unknown offsets */
if (parent->offset != (guint32)-1)
buffer->offset = parent->offset + offset;
else
buffer->offset = (guint32)-1;
/* again, for lack of better, copy parent's timestamp */
buffer->timestamp = parent->timestamp;
buffer->maxage = parent->maxage;
/* if the parent buffer is a subbuffer itself, use its parent, a real buffer */
if (parent->parent != NULL)
parent = parent->parent;
/* set parentage and reference the parent */
buffer->parent = parent;
gst_buffer_ref (parent);
buffer->pool = NULL;
return buffer;
}
/* FIXME FIXME: how does this overlap with the newly-added gst_buffer_span() ??? */
/**
* gst_buffer_append:
* @first: #GstBuffer to append to
* @second: #GstBuffer to append
*
* Creates a new buffer by appending the data of second to the
* existing data of first. This will grow first if first is unused elsewhere,
* or create a newly allocated buffer if it is in use.
* second will not be changed.
*
* Returns: a new #GstBuffer
*/
GstBuffer*
gst_buffer_append (GstBuffer *first,
GstBuffer *second)
{
guint size;
GstBuffer *newbuf = NULL;
GstBuffer *buffer = NULL;
g_return_val_if_fail (first != NULL, NULL);
g_return_val_if_fail (second != NULL, NULL);
g_return_val_if_fail (first->pool == NULL, NULL);
g_return_val_if_fail (GST_BUFFER_REFCOUNT (first) > 0, NULL);
g_return_val_if_fail (GST_BUFFER_REFCOUNT (second) > 0, NULL);
GST_INFO (GST_CAT_BUFFER,"appending buffers %p and %p",first, second);
GST_BUFFER_LOCK (first);
/* is the buffer used by anyone else ? */
if (GST_BUFFER_REFCOUNT (first) == 1 && first->parent == NULL
&& !GST_BUFFER_FLAG_IS_SET (first, GST_BUFFER_DONTFREE)) {
/* it's not, so we can realloc and expand the first buffer,
* filling it with the second's data */
size = first->size;
first->size += second->size;
first->data = g_realloc (first->data, first->size);
memcpy(first->data + size, second->data, second->size);
GST_BUFFER_UNLOCK (first);
buffer = first;
}
else {
/* the buffer is used, create a new one */
newbuf = gst_buffer_new ();
newbuf->size = first->size + second->size;
newbuf->data = g_malloc (newbuf->size);
memcpy (newbuf->data, first->data, first->size);
memcpy (newbuf->data + first->size, second->data, second->size);
GST_BUFFER_TIMESTAMP (newbuf) = GST_BUFFER_TIMESTAMP (first);
GST_BUFFER_UNLOCK (first);
gst_buffer_unref (first);
buffer = newbuf;
}
return buffer;
}
/**
* gst_buffer_destroy:
* @buffer: #GstBuffer to destroy
*
* Destroys the buffer. Actual data will be retained if DONTFREE is set.
*/
void
gst_buffer_destroy (GstBuffer *buffer)
{
g_return_if_fail (buffer != NULL);
GST_INFO (GST_CAT_BUFFER, "freeing %sbuffer %p",
(buffer->parent?"sub":""),
buffer);
/* free the data only if there is some, DONTFREE isn't set, and not sub */
if (GST_BUFFER_DATA (buffer) &&
!GST_BUFFER_FLAG_IS_SET (buffer, GST_BUFFER_DONTFREE) &&
(buffer->parent == NULL)) {
/* if there's a free function, use it */
if (buffer->free != NULL) {
(buffer->free)(buffer);
} else {
g_free (GST_BUFFER_DATA (buffer));
}
}
/* unreference the parent if there is one */
if (buffer->parent != NULL)
gst_buffer_unref (buffer->parent);
g_mutex_free (buffer->lock);
/* g_print("freed mutex\n"); */
#ifdef GST_DEBUG_ENABLED
/* make it hard to reuse by mistake */
memset (buffer, 0, sizeof (GstBuffer));
#endif
/* remove it entirely from memory */
g_mutex_lock (_gst_buffer_chunk_lock);
g_mem_chunk_free (_gst_buffer_chunk,buffer);
_gst_buffer_live--;
g_mutex_unlock (_gst_buffer_chunk_lock);
}
/**
* gst_buffer_ref:
* @buffer: a #GstBuffer to reference
*
* Increments the reference count of this buffer.
*/
void
gst_buffer_ref (GstBuffer *buffer)
{
g_return_if_fail (buffer != NULL);
GST_INFO (GST_CAT_BUFFER, "ref buffer %p, current count is %d", buffer,GST_BUFFER_REFCOUNT(buffer));
g_return_if_fail (GST_BUFFER_REFCOUNT(buffer) > 0);
#ifdef HAVE_ATOMIC_H
atomic_inc (&(buffer->refcount));
#else
GST_BUFFER_LOCK (buffer);
buffer->refcount++;
GST_BUFFER_UNLOCK (buffer);
#endif
}
/**
* gst_buffer_ref_by_count:
* @buffer: a #GstBuffer to reference
* @count: the number to increment the reference count by
*
* Increments the reference count of this buffer by the given number.
*/
void
gst_buffer_ref_by_count (GstBuffer *buffer, gint count)
{
g_return_if_fail (buffer != NULL);
g_return_if_fail (count >= 0);
#ifdef HAVE_ATOMIC_H
g_return_if_fail (atomic_read (&(buffer->refcount)) > 0);
atomic_add (count, &(buffer->refcount));
#else
g_return_if_fail (buffer->refcount > 0);
GST_BUFFER_LOCK (buffer);
buffer->refcount += count;
GST_BUFFER_UNLOCK (buffer);
#endif
}
/**
* gst_buffer_unref:
* @buffer: a #GstBuffer to unreference
*
* Decrements the refcount of this buffer. If the refcount is
* zero, the buffer will be destroyed.
*/
void
gst_buffer_unref (GstBuffer *buffer)
{
gint zero;
g_return_if_fail (buffer != NULL);
GST_INFO (GST_CAT_BUFFER, "unref buffer %p, current count is %d", buffer,GST_BUFFER_REFCOUNT(buffer));
g_return_if_fail (GST_BUFFER_REFCOUNT(buffer) > 0);
#ifdef HAVE_ATOMIC_H
zero = atomic_dec_and_test (&(buffer->refcount));
#else
GST_BUFFER_LOCK (buffer);
buffer->refcount--;
zero = (buffer->refcount == 0);
GST_BUFFER_UNLOCK (buffer);
#endif
/* if we ended up with the refcount at zero, destroy the buffer */
if (zero) {
gst_buffer_destroy (buffer);
}
}
/**
* gst_buffer_copy:
* @buffer: a #GstBuffer to make a copy of
*
* Make a full newly allocated copy of the given buffer, data and all.
*
* Returns: new #GstBuffer
*/
GstBuffer *
gst_buffer_copy (GstBuffer *buffer)
{
GstBuffer *newbuf;
g_return_val_if_fail (GST_BUFFER_REFCOUNT(buffer) > 0, NULL);
/* if a copy function exists, use it, else copy the bytes */
if (buffer->copy != NULL) {
newbuf = (buffer->copy)(buffer);
} else {
/* allocate a new buffer */
newbuf = gst_buffer_new();
/* copy the absolute size */
newbuf->size = buffer->size;
/* allocate space for the copy */
newbuf->data = (guchar *)g_malloc (buffer->size);
/* copy the data straight across */
memcpy(newbuf->data,buffer->data,buffer->size);
/* the new maxsize is the same as the size, since we just malloc'd it */
newbuf->maxsize = newbuf->size;
}
newbuf->offset = buffer->offset;
newbuf->timestamp = buffer->timestamp;
newbuf->maxage = buffer->maxage;
/* since we just created a new buffer, so we have no ties to old stuff */
newbuf->parent = NULL;
newbuf->pool = NULL;
return newbuf;
}
/**
* gst_buffer_is_span_fast:
* @buf1: first source buffer
* @buf2: second source buffer
*
* 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(buf1) > 0, FALSE);
g_return_val_if_fail (GST_BUFFER_REFCOUNT(buf2) > 0, FALSE);
return (buf1->parent && buf2->parent &&
(buf1->parent == buf2->parent) &&
((buf1->data + buf1->size) == buf2->data));
}
/**
* gst_buffer_span:
* @buf1: first source #GstBuffer to merge
* @offset: offset in first buffer to start new buffer
* @buf2: second source #GstBuffer to merge
* @len: length of 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.
*
* Returns: a new #GstBuffer that spans the two source buffers
*/
/* FIXME need to think about CoW and such... */
GstBuffer *
gst_buffer_span (GstBuffer *buf1, guint32 offset, GstBuffer *buf2, guint32 len)
{
GstBuffer *newbuf;
g_return_val_if_fail (GST_BUFFER_REFCOUNT(buf1) > 0, NULL);
g_return_val_if_fail (GST_BUFFER_REFCOUNT(buf2) > 0, NULL);
/* make sure buf1 has a lower address than buf2 */
if (buf1->data > buf2->data) {
GstBuffer *tmp = buf1;
/* g_print ("swapping buffers\n"); */
buf1 = buf2;
buf2 = tmp;
}
/* if the two buffers have the same parent and are adjacent */
if (gst_buffer_is_span_fast(buf1,buf2)) {
/* we simply create a subbuffer of the common parent */
newbuf = gst_buffer_create_sub (buf1->parent, buf1->data - (buf1->parent->data) + offset, len);
}
else {
/* g_print ("slow path taken in buffer_span\n"); */
/* otherwise we simply have to brute-force copy the buffers */
newbuf = gst_buffer_new ();
/* put in new size */
newbuf->size = len;
/* allocate space for the copy */
newbuf->data = (guchar *)g_malloc(len);
/* 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 (newbuf->offset != (guint32)-1)
newbuf->offset = buf1->offset + offset;
newbuf->timestamp = buf1->timestamp;
if (buf2->maxage > buf1->maxage) newbuf->maxage = buf2->maxage;
else newbuf->maxage = buf1->maxage;
}
return newbuf;
}
/**
* gst_buffer_merge:
* @buf1: first source #GstBuffer to merge
* @buf2: 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: a 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);
GST_BUFFER_TIMESTAMP (result) = GST_BUFFER_TIMESTAMP (buf1);
return result;
}