vpx_ports/mem.h


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/*
 *  Copyright (c) 2010 The WebM project authors. All Rights Reserved.
 *
 *  Use of this source code is governed by a BSD-style license
 *  that can be found in the LICENSE file in the root of the source
 *  tree. An additional intellectual property rights grant can be found
 *  in the file PATENTS.  All contributing project authors may
 *  be found in the AUTHORS file in the root of the source tree.
 */


#ifndef VPX_PORTS_MEM_H
#define VPX_PORTS_MEM_H
#include "vpx_config.h"
#include "vpx/vpx_integer.h"

#if defined(__GNUC__) && __GNUC__
#define DECLARE_ALIGNED(n,typ,val)  typ val __attribute__ ((aligned (n)))
#elif defined(_MSC_VER)
#define DECLARE_ALIGNED(n,typ,val)  __declspec(align(n)) typ val
#else
#warning No alignment directives known for this compiler.
#define DECLARE_ALIGNED(n,typ,val)  typ val
#endif
#endif


/* Declare an aligned array on the stack, for situations where the stack
 * pointer may not have the alignment we expect. Creates an array with a
 * modified name, then defines val to be a pointer, and aligns that pointer
 * within the array.
 */
#define DECLARE_ALIGNED_ARRAY(a,typ,val,n)\
typ val##_[(n)+(a)/sizeof(typ)+1];\
typ *val = (typ*)((((intptr_t)val##_)+(a)-1)&((intptr_t)-(a)))


/* Indicates that the usage of the specified variable has been audited to assure
 * that it's safe to use uninitialized. Silences 'may be used uninitialized'
 * warnings on gcc.
 */
#if defined(__GNUC__) && __GNUC__
#define UNINITIALIZED_IS_SAFE(x) x=x
#else
#define UNINITIALIZED_IS_SAFE(x) x
#endif