gstreamer/gst/gstbuffer.c

370 lines
9.2 KiB
C
Raw Normal View History

/* 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.
*/
Changes made to the DEBUG system. New header file gstdebug.h holds the stuff to keep it out of gst.h's hair. DEBUG ... Original commit message from CVS: Changes made to the DEBUG system. New header file gstdebug.h holds the stuff to keep it out of gst.h's hair. DEBUG prints out the process id, cothread id, source filename and line number. Two new macros DEBUG_ENTER and DEBUG_LEAVE are used to show the entry and exit of a given function. This eventually might be used to construct call trace graphs, even taking cothreads into account. This would be quite useful in visualizing the scheduling mechanism. Minor changes to various debug messages. Also sitting in gstdebug.h is a prototypical DEBUG_ENTER that's capable of performing DEBUG_LEAVE automatically. It does this by utilizing a little-known GCC extension that allows one to call a function with the same parameters as the current function. The macro uses this to basically call itself. A boolean is used to ensure that when it calls itself it actually runs the body of the function. In the meantime it prints stuff out before and after the real function, as well as constructing a debugging string. This can be used eventually to provide call-wide data on the DEBUG lines, instead of having to replicate data on each call to DEBUG. More research is needed into how this would most cleanly be fit into some other chunk of code, like GStreamer (I think of this DEBUG trick as a separate project, sorta). Unfortunately, the aforementioned DEBUG trick interacts quite poorly with cothreads. Almost any time it's used in a function that has anything remotely to do with a cothread context (as in, it runs in one), a segfault results from the __builtin_apply call, which is the heart of the whole thing. If someone who really knows assembly could analyze the resulting code to see what's really going on, we might find a way to fix either the macro or the cothreads (I'm thinking that there's something we missed in constructing the cothreads themselves) so this works in all cases. In the meantime, please insert both DEBUG_ENTER and DEBUG_LEAVE in your functions. Be sure to put DEBUG_ENTER after your variable declarations and before any functional code, not to put the function name in any DEBUG strings (it's already there, trust me), and put a DEBUG_LEAVE if you care enough. Changes are going to happen in the way DEBUGs and other printouts occur, so stay tuned.
2000-12-04 09:35:08 +00:00
/* this file makes too much noise for most debugging sessions */
#define GST_DEBUG_FORCE_DISABLE
#include "gst_private.h"
#include "gstbuffer.h"
static GMemChunk *_gst_buffer_chunk;
static GMutex *_gst_buffer_chunk_lock;
void
_gst_buffer_initialize (void)
{
int buffersize = sizeof(GstBuffer);
// 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_new:
*
* Create a new buffer.
*
* Returns: new buffer
*/
GstBuffer*
gst_buffer_new(void)
{
GstBuffer *buffer;
g_mutex_lock (_gst_buffer_chunk_lock);
buffer = g_mem_chunk_alloc (_gst_buffer_chunk);
g_mutex_unlock (_gst_buffer_chunk_lock);
GST_INFO (GST_CAT_BUFFER,"creating new buffer %p",buffer);
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 = 0;
buffer->timestamp = 0;
buffer->parent = NULL;
buffer->pool = NULL;
buffer->free = NULL;
buffer->copy = NULL;
return buffer;
}
/**
* gst_buffer_new_from_pool:
* @pool: the buffer pool to use
*
* Create a new buffer using the specified bufferpool.
*
* Returns: new buffer
*/
GstBuffer*
gst_buffer_new_from_pool (GstBufferPool *pool)
{
return gst_buffer_pool_new_buffer (pool);
}
/**
* gst_buffer_create_sub:
* @parent: parent buffer
* @offset: offset into parent buffer
* @size: size of new subbuffer
*
* Creates a sub-buffer from the parent at a given offset.
*
* Returns: new buffer
*/
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 (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);
g_mutex_unlock (_gst_buffer_chunk_lock);
GST_INFO (GST_CAT_BUFFER,"creating new subbuffer %p from parent %p", buffer, parent);
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->offset = parent->offset + offset;
buffer->maxsize = parent->size - offset;
// 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 the new subbuffer
return buffer;
}
/**
* gst_buffer_append:
* @buffer: a buffer
* @append: the buffer to append
*
* Creates a new buffer by appending the data of append to the
* existing data of buffer.
*
* Returns: new buffer
*/
GstBuffer*
gst_buffer_append (GstBuffer *buffer,
GstBuffer *append)
{
guint size;
GstBuffer *newbuf;
g_return_val_if_fail (buffer != NULL, NULL);
g_return_val_if_fail (append != NULL, NULL);
g_return_val_if_fail (buffer->pool == NULL, NULL);
GST_INFO (GST_CAT_BUFFER,"appending buffers %p and %p",buffer,append);
GST_BUFFER_LOCK (buffer);
// the buffer is not used by anyone else
if (GST_BUFFER_REFCOUNT (buffer) == 1 && buffer->parent == NULL
&& !GST_BUFFER_FLAG_IS_SET (buffer, GST_BUFFER_DONTFREE)) {
// save the old size
size = buffer->size;
buffer->size += append->size;
buffer->data = g_realloc (buffer->data, buffer->size);
memcpy(buffer->data + size, append->data, append->size);
GST_BUFFER_UNLOCK (buffer);
}
// the buffer is used, create a new one
else {
newbuf = gst_buffer_new ();
newbuf->size = buffer->size+append->size;
newbuf->data = g_malloc (newbuf->size);
memcpy (newbuf->data, buffer->data, buffer->size);
memcpy (newbuf->data+buffer->size, append->data, append->size);
GST_BUFFER_UNLOCK (buffer);
gst_buffer_unref (buffer);
buffer = newbuf;
}
return buffer;
}
/**
* gst_buffer_destroy:
* @buffer: the GstBuffer to destroy
*
* destroy the buffer
*/
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");
// remove it entirely from memory
g_mutex_lock (_gst_buffer_chunk_lock);
g_mem_chunk_free (_gst_buffer_chunk,buffer);
g_mutex_unlock (_gst_buffer_chunk_lock);
}
/**
* gst_buffer_ref:
* @buffer: the GstBuffer to reference
*
* Increment the refcount of this buffer.
*/
void
gst_buffer_ref (GstBuffer *buffer)
{
g_return_if_fail (buffer != NULL);
GST_DEBUG (0,"referencing buffer %p\n", buffer);
#ifdef HAVE_ATOMIC_H
//g_return_if_fail(atomic_read(&(buffer->refcount)) > 0);
atomic_inc (&(buffer->refcount));
#else
g_return_if_fail (buffer->refcount > 0);
GST_BUFFER_LOCK (buffer);
buffer->refcount++;
GST_BUFFER_UNLOCK (buffer);
#endif
}
/**
* gst_buffer_ref_by_count:
* @buffer: the GstBuffer to reference
* @count: a number
*
* Increment the refcount of this buffer by the given number.
*/
void
gst_buffer_ref_by_count (GstBuffer *buffer, int 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: the GstBuffer to unref
*
* Decrement 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_DEBUG (0,"unreferencing buffer %p\n", buffer);
#ifdef HAVE_ATOMIC_H
g_return_if_fail (atomic_read (&(buffer->refcount)) > 0);
zero = atomic_dec_and_test (&(buffer->refcount));
#else
g_return_if_fail (buffer->refcount > 0);
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) {
// if it came from a pool, give it back
if (buffer->pool != NULL) {
gst_buffer_pool_destroy_buffer (buffer->pool, buffer);
return;
}
else {
gst_buffer_destroy (buffer);
}
}
}
/**
* gst_buffer_copy:
* @buffer: the orignal GstBuffer to make a copy of
*
* Make a full copy of the give buffer, data and all.
*
* Returns: new buffer
*/
GstBuffer *
gst_buffer_copy (GstBuffer *buffer)
{
GstBuffer *newbuf;
// allocate a new buffer
newbuf = gst_buffer_new();
// if a copy function exists, use it, else copy the bytes
if (buffer->copy != NULL) {
(buffer->copy)(buffer,newbuf);
} else {
// 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;
}