gstreamer/gst/gstbufferpool.c

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/* GStreamer
* Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
* 2000 Wim Taymans <wtay@chello.be>
*
* gstbufferpool.c: Buffer-pool 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.
*/
#include "gst_private.h"
#include "gstbuffer.h"
static GMutex *_default_pool_lock;
static GHashTable *_default_pools;
static GstBuffer* gst_buffer_pool_default_create (GstBufferPool *pool, gpointer user_data);
static void gst_buffer_pool_default_destroy (GstBufferPool *pool, GstBuffer *buffer, gpointer user_data);
void
_gst_buffer_pool_initialize (void)
{
_default_pools = g_hash_table_new(NULL,NULL);
_default_pool_lock = g_mutex_new ();
}
/**
* gst_buffer_pool_new:
*
* Create a new buffer pool.
*
* Returns: new buffer pool
*/
GstBufferPool*
gst_buffer_pool_new (void)
{
GstBufferPool *pool;
pool = g_malloc (sizeof(GstBufferPool));
GST_DEBUG (0,"BUF: allocating new buffer pool %p\n", pool);
pool->new_buffer = NULL;
pool->destroy_buffer = NULL;
pool->lock = g_mutex_new ();
#ifdef HAVE_ATOMIC_H
atomic_set (&pool->refcount, 1);
#else
pool->refcount = 1;
#endif
return pool;
}
/**
* gst_buffer_pool_ref:
* @pool: the GstBufferPool to reference
*
* Increment the refcount of this buffer pool.
*/
void
gst_buffer_pool_ref (GstBufferPool *pool)
{
g_return_if_fail (pool != NULL);
GST_DEBUG(0,"referencing buffer pool %p from %d\n", pool, GST_BUFFER_POOL_REFCOUNT(pool));
#ifdef HAVE_ATOMIC_H
atomic_inc (&(pool->refcount));
#else
g_return_if_fail (pool->refcount > 0);
GST_BUFFER_POOL_LOCK (pool);
buffer->refcount++;
GST_BUFFER_POOL_UNLOCK (pool);
#endif
}
/**
* gst_buffer_pool_ref_by_count:
* @pool: the GstBufferPool to reference
* @count: a number
*
* Increment the refcount of this buffer pool by the given number.
*/
void
gst_buffer_pool_ref_by_count (GstBufferPool *pool, int count)
{
g_return_if_fail (pool != NULL);
g_return_if_fail (count > 0);
#ifdef HAVE_ATOMIC_H
g_return_if_fail (atomic_read (&(pool->refcount)) > 0);
atomic_add (count, &(pool->refcount));
#else
g_return_if_fail (pool->refcount > 0);
GST_BUFFER_POOL_LOCK (pool);
pool->refcount += count;
GST_BUFFER_POOL_UNLOCK (pool);
#endif
}
/**
* gst_buffer_pool_unref:
* @pool: the GstBufferPool to unref
*
* Decrement the refcount of this buffer pool. If the refcount is
* zero and the pool is a default implementation,
* the buffer pool will be destroyed.
*/
void
gst_buffer_pool_unref (GstBufferPool *pool)
{
gint zero;
g_return_if_fail (pool != NULL);
GST_DEBUG(0,"unreferencing buffer pool %p from %d\n", pool, GST_BUFFER_POOL_REFCOUNT(pool));
#ifdef HAVE_ATOMIC_H
g_return_if_fail (atomic_read (&(pool->refcount)) > 0);
zero = atomic_dec_and_test (&(pool->refcount));
#else
g_return_if_fail (pool->refcount > 0);
GST_BUFFER_POOL_LOCK (pool);
pool->refcount--;
zero = (pool->refcount == 0);
GST_BUFFER_POOL_UNLOCK (pool);
#endif
/* if we ended up with the refcount at zero, destroy the buffer pool*/
if (zero) {
gst_buffer_pool_destroy (pool);
}
}
/**
* gst_buffer_pool_set_create_function:
* @pool: the pool to set the create function for
* @create: the create function
* @user_data: any user data to be passed in the create function
*
* Sets the function that will be called when a buffer is created
* from this pool.
*/
void
gst_buffer_pool_set_create_function (GstBufferPool *pool,
GstBufferPoolCreateFunction create,
gpointer user_data)
{
g_return_if_fail (pool != NULL);
pool->new_buffer = create;
pool->new_user_data = user_data;
}
/**
* gst_buffer_pool_set_destroy_function:
* @pool: the pool to set the destroy function for
* @destroy: the destroy function
* @user_data: any user data to be passed in the create function
*
* Sets the function that will be called when a buffer is destroyed
* from this pool.
*/
void
gst_buffer_pool_set_destroy_function (GstBufferPool *pool,
GstBufferPoolDestroyFunction destroy,
gpointer user_data)
{
g_return_if_fail (pool != NULL);
pool->destroy_buffer = destroy;
pool->destroy_user_data = user_data;
}
/**
* gst_buffer_pool_destroy:
* @pool: the pool to destroy
*
* Frees the memory for this bufferpool.
*/
void
gst_buffer_pool_destroy (GstBufferPool *pool)
{
GMemChunk *data_chunk;
g_return_if_fail (pool != NULL);
// if its a default buffer pool, we know how to free the user data
if (pool->new_buffer == gst_buffer_pool_default_create &&
pool->destroy_buffer == gst_buffer_pool_default_destroy){
GST_DEBUG(0,"destroying default buffer pool %p\n", pool);
data_chunk = (GMemChunk*)pool->new_user_data;
g_mem_chunk_reset(data_chunk);
g_free(data_chunk);
}
g_free(pool);
}
/**
* gst_buffer_pool_new_buffer:
* @pool: the pool to create the buffer from
*
* Uses the given pool to create a new buffer.
*
* Returns: The new buffer
*/
GstBuffer*
gst_buffer_pool_new_buffer (GstBufferPool *pool)
{
GstBuffer *buffer;
g_return_val_if_fail (pool != NULL, NULL);
buffer = pool->new_buffer (pool, pool->new_user_data);
buffer->pool = pool;
return buffer;
}
/**
* gst_buffer_pool_destroy_buffer:
* @pool: the pool to return the buffer to
* @buffer: the buffer to return to the pool
*
* Gives a buffer back to the given pool.
*/
void
gst_buffer_pool_destroy_buffer (GstBufferPool *pool,
GstBuffer *buffer)
{
g_return_if_fail (pool != NULL);
g_return_if_fail (buffer != NULL);
pool->destroy_buffer (pool, buffer, pool->new_user_data);
}
/**
* gst_buffer_pool_get_default:
* @pool: instance of GstBufferPool which is no longer required (or NULL if it doesn't exist)
* @buffer_size: the number of bytes this buffer will store
* @pool_size: the default number of buffers to be preallocated
*
* Returns an instance of a buffer pool using the default
* implementation. If a buffer pool instance with the same buffer_size
* already exists this will be returned, otherwise a new instance will
* be created.
*
* Returns: an instance of GstBufferPool
*/
GstBufferPool*
gst_buffer_pool_get_default (GstBufferPool *oldpool, guint buffer_size, guint pool_size)
{
GstBufferPool *pool;
GMemChunk *data_chunk;
guint real_buffer_size;
// round up to the nearest 32 bytes for cache-line and other efficiencies
real_buffer_size = (((buffer_size-1) / 32) + 1) * 32;
// check for an existing GstBufferPool with the same real_buffer_size
// (we won't worry about the pool_size)
g_mutex_lock (_default_pool_lock);
pool = (GstBufferPool*)g_hash_table_lookup(_default_pools,GINT_TO_POINTER(real_buffer_size));
g_mutex_unlock (_default_pool_lock);
if (pool != NULL){
if (oldpool != pool){
gst_buffer_pool_ref(pool);
if (oldpool != NULL){
gst_buffer_pool_unref(oldpool);
}
}
return pool;
}
data_chunk = g_mem_chunk_new ("GstBufferPoolDefault", real_buffer_size,
real_buffer_size * pool_size, G_ALLOC_AND_FREE);
pool = gst_buffer_pool_new();
gst_buffer_pool_set_create_function (pool, gst_buffer_pool_default_create, data_chunk);
gst_buffer_pool_set_destroy_function (pool, gst_buffer_pool_default_destroy, data_chunk);
g_mutex_lock (_default_pool_lock);
g_hash_table_insert(_default_pools,GINT_TO_POINTER(real_buffer_size),pool);
g_mutex_unlock (_default_pool_lock);
GST_DEBUG(0,"new buffer pool %p bytes:%d size:%d\n", pool, real_buffer_size, pool_size);
if (oldpool != NULL){
gst_buffer_pool_unref(oldpool);
}
return pool;
}
static GstBuffer*
gst_buffer_pool_default_create (GstBufferPool *pool, gpointer user_data)
{
GMemChunk *data_chunk = (GMemChunk*)user_data;
GstBuffer *buffer;
gst_buffer_pool_ref(pool);
buffer = gst_buffer_new();
GST_BUFFER_FLAG_SET(buffer,GST_BUFFER_DONTFREE);
buffer->pool = pool;
g_mutex_lock (pool->lock);
GST_BUFFER_DATA(buffer) = g_mem_chunk_alloc(data_chunk);
g_mutex_unlock (pool->lock);
return buffer;
}
static void
gst_buffer_pool_default_destroy (GstBufferPool *pool, GstBuffer *buffer, gpointer user_data)
{
GMemChunk *data_chunk = (GMemChunk*)user_data;
gpointer data = GST_BUFFER_DATA(buffer);
g_mutex_lock (pool->lock);
g_mem_chunk_free (data_chunk,data);
g_mutex_unlock (pool->lock);
buffer->pool = NULL;
gst_buffer_pool_unref(pool);
gst_buffer_destroy (buffer);
}