added a default bufferpool factory function. it reuses existing instances of bufferpool if requests are made for exis...

Original commit message from CVS:
added a default bufferpool factory function. it reuses existing instances of bufferpool if requests are made for existing buffer sizes

gst/gst.c

@@ -84,6 +84,7 @@ gst_init (int *argc, char **argv[])
   _gst_caps_initialize ();
   _gst_plugin_initialize ();
   _gst_buffer_initialize ();
+  _gst_buffer_pool_initialize ();
 
   /* register some standard builtin types */
   gst_elementfactory_new ("bin", gst_bin_get_type (), &gst_bin_details);

gst/gstbufferpool.c

@@ -25,6 +25,18 @@
 
 #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:
@@ -138,3 +150,64 @@ gst_buffer_pool_destroy_buffer (GstBufferPool *pool,
 
   pool->destroy_buffer (pool, buffer, pool->new_user_data);
 }
+
+GstBufferPool*
+gst_buffer_pool_get_default (guint buffer_size, guint pool_size)
+{
+  GstBufferPool *pool;
+  GMemChunk *data_chunk;
+  guint real_buffer_size;
+  
+  // check for an existing GstBufferPool with the same buffer_size
+  // (we won't worry about the pool_size)
+  if ((pool = (GstBufferPool*)g_hash_table_lookup(_default_pools,GINT_TO_POINTER(buffer_size)))){
+    return pool;
+  }
+  
+  // g_print("new buffer pool bytes:%d size:%d\n", buffer_size, pool_size);
+  
+  // round up to the nearest 32 bytes for cache-line and other efficiencies
+  real_buffer_size = ((buffer_size-1 / 32) + 1) * 32;
+
+  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_hash_table_insert(_default_pools,GINT_TO_POINTER(buffer_size),pool);
+  return pool;
+}
+
+static GstBuffer* 
+gst_buffer_pool_default_create (GstBufferPool *pool, gpointer user_data)
+{
+  GMemChunk *data_chunk = (GMemChunk*)user_data;
+  GstBuffer *buffer;
+  
+  buffer = gst_buffer_new();
+  GST_BUFFER_FLAG_SET(buffer,GST_BUFFER_DONTFREE);
+  buffer->pool = pool;
+
+  g_mutex_lock (default_pool_lock);
+  GST_BUFFER_DATA(buffer) = g_mem_chunk_alloc(data_chunk);
+  g_mutex_unlock (default_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 (default_pool_lock);
+  g_mem_chunk_free (data_chunk,data);
+  g_mutex_unlock (default_pool_lock);
+
+  buffer->pool = NULL;
+  gst_buffer_destroy (buffer);
+  
+}

gst/gstbufferpool.h

@@ -67,6 +67,9 @@ void 			gst_buffer_pool_set_destroy_function	(GstBufferPool *pool,
 /* destroying the buffer pool */
 void 			gst_buffer_pool_destroy			(GstBufferPool *pool);
 
+/* a default buffer pool implementation */
+GstBufferPool* gst_buffer_pool_get_default (guint buffer_size, guint pool_size);
+
 #ifdef __cplusplus
 }
 #endif /* __cplusplus */