gstreamer/tests/examples/memory/my-vidmem.c

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/* 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., 51 Franklin St, Fifth Floor,
* Boston, MA 02110-1301, USA.
*/
#include "my-vidmem.h"
static GstAllocator *_my_allocator;
typedef struct
{
GstMemory mem;
guint format;
guint width;
guint height;
gpointer data;
} MyVidmem;
static GstMemory *
_my_alloc (GstAllocator * allocator, gsize size, GstAllocationParams * params)
{
g_warning ("Use my_vidmem_alloc() to allocate from this allocator");
return NULL;
}
static void
_my_free (GstAllocator * allocator, GstMemory * mem)
{
MyVidmem *vmem = (MyVidmem *) mem;
g_free (vmem->data);
g_slice_free (MyVidmem, vmem);
GST_DEBUG ("%p: freed", vmem);
}
static gpointer
_my_vidmem_map (MyVidmem * 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_vidmem_unmap (MyVidmem * mem)
{
GST_DEBUG ("%p: unmapped", mem);
return TRUE;
}
static MyVidmem *
_my_vidmem_share (MyVidmem * mem, gssize offset, gsize size)
{
MyVidmem *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 (MyVidmem);
/* 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_vidmem_map (mem, mem->mem.maxsize, GST_MAP_READ);
return sub;
}
typedef struct
{
GstAllocator parent;
} MyVidmemAllocator;
typedef struct
{
GstAllocatorClass parent_class;
} MyVidmemAllocatorClass;
GType my_vidmem_allocator_get_type (void);
G_DEFINE_TYPE (MyVidmemAllocator, my_vidmem_allocator, GST_TYPE_ALLOCATOR);
static void
my_vidmem_allocator_class_init (MyVidmemAllocatorClass * klass)
{
GstAllocatorClass *allocator_class;
allocator_class = (GstAllocatorClass *) klass;
allocator_class->alloc = _my_alloc;
allocator_class->free = _my_free;
}
static void
my_vidmem_allocator_init (MyVidmemAllocator * allocator)
{
GstAllocator *alloc = GST_ALLOCATOR_CAST (allocator);
alloc->mem_type = "MyVidmem";
alloc->mem_map = (GstMemoryMapFunction) _my_vidmem_map;
alloc->mem_unmap = (GstMemoryUnmapFunction) _my_vidmem_unmap;
alloc->mem_share = (GstMemoryShareFunction) _my_vidmem_share;
}
void
my_vidmem_init (void)
{
_my_allocator = g_object_new (my_vidmem_allocator_get_type (), NULL);
gst_allocator_register ("MyVidmem", gst_object_ref (_my_allocator));
}
GstMemory *
my_vidmem_alloc (guint format, guint width, guint height)
{
MyVidmem *mem;
gsize maxsize;
GST_DEBUG ("alloc frame format %u %ux%u", format, width, height);
maxsize = (GST_ROUND_UP_4 (width) * height);
mem = g_slice_new (MyVidmem);
gst_memory_init (GST_MEMORY_CAST (mem), 0, _my_allocator, NULL,
maxsize, 31, 0, maxsize);
mem->format = format;
mem->width = width;
mem->height = height;
mem->data = NULL;
return (GstMemory *) mem;
}
gboolean
my_is_vidmem (GstMemory * mem)
{
return mem->allocator == _my_allocator;
}
void
my_vidmem_get_format (GstMemory * mem, guint * format, guint * width,
guint * height)
{
MyVidmem *vmem = (MyVidmem *) mem;
*format = vmem->format;
*width = vmem->width;
*height = vmem->height;
}