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/**************************************************************************
*
* Copyright 2007 Tungsten Graphics, Inc., Cedar Park, Texas.
* All Rights Reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sub license, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice (including the
* next paragraph) shall be included in all copies or substantial portions
* of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
* IN NO EVENT SHALL TUNGSTEN GRAPHICS AND/OR ITS SUPPLIERS BE LIABLE FOR
* ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*
**************************************************************************/
/**
* \file
* Null buffer implementation.
*
* We have a special null buffer object so that we can safely call buffer
* operations without having to check whether the buffer pointer is null or not.
*
* \author José Fonseca <jrfonseca@tungstengraphics.com>
*/
#include "pipe/p_winsys.h"
#include "pipe/p_defines.h"
#include "pb_buffer.h"
static void
null_buffer_reference(struct pipe_buffer *buf)
{
/* No-op */
}
static void
null_buffer_release(struct pipe_buffer *buf)
{
/* No-op */
}
static void *
null_buffer_map(struct pipe_buffer *buf,
unsigned flags)
{
assert(0);
return NULL;
}
static void
null_buffer_unmap(struct pipe_buffer *buf)
{
assert(0);
}
static void
null_buffer_get_base_buffer(struct pipe_buffer *buf,
struct pipe_buffer **base_buf,
unsigned *offset)
{
*base_buf = buf;
*offset = 0;
}
const struct pipe_buffer_vtbl
pipe_buffer_vtbl = {
null_buffer_reference,
null_buffer_release,
null_buffer_map,
null_buffer_unmap,
null_buffer_get_base_buffer
};
struct pipe_buffer
null_buffer = {
&pipe_buffer_vtbl
};
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