gstreamer/tests/examples/memory/my-memory.c
Wim Taymans a2027b5e9b allocator: remove user_data from alloc vmethod
Remove the user_data from the alloc vmethod. Subclasses that implement a new
alloc function can also implement their own vmethod to pass extra arguments. We
can then also require that custom allocators implement an alloc function so that
gst_allocator_alloc() always works.
2012-07-27 12:17:29 +02:00

159 lines
3.7 KiB
C

/* GStreamer
* Copyright (C) 2012 Wim Taymans <wim.taymans@gmail.be>
*
* 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 "my-memory.h"
typedef struct
{
GstMemory mem;
gpointer data;
} MyMemory;
static GstMemory *
_my_alloc (GstAllocator * allocator, gsize size, GstAllocationParams * params)
{
MyMemory *mem;
gsize maxsize = size + params->prefix + params->padding;
GST_DEBUG ("alloc from allocator %p", allocator);
mem = g_slice_new (MyMemory);
gst_memory_init (GST_MEMORY_CAST (mem), params->flags, allocator, NULL,
maxsize, params->align, params->prefix, size);
mem->data = NULL;
return (GstMemory *) mem;
}
static void
_my_free (GstAllocator * allocator, GstMemory * mem)
{
MyMemory *mmem = (MyMemory *) mem;
g_free (mmem->data);
g_slice_free (MyMemory, mmem);
GST_DEBUG ("%p: freed", mmem);
}
static gpointer
_my_mem_map (MyMemory * mem, gsize maxsize, GstMapFlags flags)
{
gpointer res;
while (TRUE) {
if ((res = g_atomic_pointer_get (&mem->data)) != NULL)
break;
res = g_malloc (maxsize);
if (g_atomic_pointer_compare_and_exchange (&mem->data, NULL, res))
break;
g_free (res);
}
GST_DEBUG ("%p: mapped %p", mem, res);
return res;
}
static gboolean
_my_mem_unmap (MyMemory * mem)
{
GST_DEBUG ("%p: unmapped", mem);
return TRUE;
}
static MyMemory *
_my_mem_share (MyMemory * mem, gssize offset, gsize size)
{
MyMemory *sub;
GstMemory *parent;
GST_DEBUG ("%p: share %" G_GSSIZE_FORMAT " %" G_GSIZE_FORMAT, mem, offset,
size);
/* find the real parent */
if ((parent = mem->mem.parent) == NULL)
parent = (GstMemory *) mem;
if (size == -1)
size = mem->mem.size - offset;
sub = g_slice_new (MyMemory);
/* the shared memory is always readonly */
gst_memory_init (GST_MEMORY_CAST (sub), GST_MINI_OBJECT_FLAGS (parent) |
GST_MINI_OBJECT_FLAG_LOCK_READONLY, mem->mem.allocator, parent,
mem->mem.maxsize, mem->mem.align, mem->mem.offset + offset, size);
/* install pointer */
sub->data = _my_mem_map (mem, mem->mem.maxsize, GST_MAP_READ);
return sub;
}
typedef struct
{
GstAllocator parent;
} MyMemoryAllocator;
typedef struct
{
GstAllocatorClass parent_class;
} MyMemoryAllocatorClass;
GType my_memory_allocator_get_type (void);
G_DEFINE_TYPE (MyMemoryAllocator, my_memory_allocator, GST_TYPE_ALLOCATOR);
static void
my_memory_allocator_class_init (MyMemoryAllocatorClass * klass)
{
GstAllocatorClass *allocator_class;
allocator_class = (GstAllocatorClass *) klass;
allocator_class->alloc = _my_alloc;
allocator_class->free = _my_free;
}
static void
my_memory_allocator_init (MyMemoryAllocator * allocator)
{
GstAllocator *alloc = GST_ALLOCATOR_CAST (allocator);
alloc->mem_type = "MyMemory";
alloc->mem_map = (GstMemoryMapFunction) _my_mem_map;
alloc->mem_unmap = (GstMemoryUnmapFunction) _my_mem_unmap;
alloc->mem_share = (GstMemoryShareFunction) _my_mem_share;
}
void
my_memory_init (void)
{
GstAllocator *allocator;
allocator = g_object_new (my_memory_allocator_get_type (), NULL);
gst_allocator_register ("MyMemory", allocator);
}