vpx_ports/mem.h

   1 /*
   2  *  Copyright (c) 2010 The WebM project authors. All Rights Reserved.
   3  *
   4  *  Use of this source code is governed by a BSD-style license
   5  *  that can be found in the LICENSE file in the root of the source
   6  *  tree. An additional intellectual property rights grant can be found
   7  *  in the file PATENTS.  All contributing project authors may
   8  *  be found in the AUTHORS file in the root of the source tree.
   9  */
  10
  11
  12 #ifndef VPX_PORTS_MEM_H_
  13 #define VPX_PORTS_MEM_H_
  14
  15 #include "vpx_config.h"
  16 #include "vpx/vpx_integer.h"
  17
  18 #if (defined(__GNUC__) && __GNUC__) || defined(__SUNPRO_C)
  19 #define DECLARE_ALIGNED(n,typ,val)  typ val __attribute__ ((aligned (n)))
  20 #elif defined(_MSC_VER)
  21 #define DECLARE_ALIGNED(n,typ,val)  __declspec(align(n)) typ val
  22 #else
  23 #warning No alignment directives known for this compiler.
  24 #define DECLARE_ALIGNED(n,typ,val)  typ val
  25 #endif
  26 #endif
  27
  28
  29 /* Declare an aligned array on the stack, for situations where the stack
  30  * pointer may not have the alignment we expect. Creates an array with a
  31  * modified name, then defines val to be a pointer, and aligns that pointer
  32  * within the array.
  33  */
  34 #define DECLARE_ALIGNED_ARRAY(a,typ,val,n)\
  35   typ val##_[(n)+(a)/sizeof(typ)+1];\
  36   typ *val = (typ*)((((intptr_t)val##_)+(a)-1)&((intptr_t)-(a)))
  37
  38
  39 /* Indicates that the usage of the specified variable has been audited to assure
  40  * that it's safe to use uninitialized. Silences 'may be used uninitialized'
  41  * warnings on gcc.
  42  */
  43 #if defined(__GNUC__) && __GNUC__
  44 #define UNINITIALIZED_IS_SAFE(x) x=x
  45 #else
  46 #define UNINITIALIZED_IS_SAFE(x) x
  47 #endif  // VPX_PORTS_MEM_H_