EdkCompatibilityPkg/Foundation/Include/EfiStdArg.h

   1 /*++
   2
   3 Copyright (c) 2004, Intel Corporation
   4 All rights reserved. This program and the accompanying materials
   5 are licensed and made available under the terms and conditions of the BSD License
   6 which accompanies this distribution.  The full text of the license may be found at
   7 http://opensource.org/licenses/bsd-license.php
   8
   9 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  10 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  11
  12 Module Name:
  13
  14   EfiStdArg.h
  15
  16 Abstract:
  17
  18   Support for variable length argument lists using the ANSI standard.
  19
  20   Since we are using the ANSI standard we used the standard nameing and
  21   did not folow the coding convention
  22
  23   VA_LIST  - typedef for argument list.
  24   VA_START (VA_LIST Marker, argument before the ...) - Init Marker for use.
  25   VA_END (VA_LIST Marker) - Clear Marker
  26   VA_ARG (VA_LIST Marker, var arg size) - Use Marker to get an argumnet from
  27     the ... list. You must know the size and pass it in this macro.
  28
  29   example:
  30
  31   UINTN
  32   ExampleVarArg (
  33     IN UINTN  NumberOfArgs,
  34     ...
  35     )
  36   {
  37     VA_LIST Marker;
  38     UINTN   Index;
  39     UINTN   Result;
  40
  41     //
  42     // Initialize the Marker
  43     //
  44     VA_START (Marker, NumberOfArgs);
  45     for (Index = 0, Result = 0; Index < NumberOfArgs; Index++) {
  46       //
  47       // The ... list is a series of UINTN values, so average them up.
  48       //
  49       Result += VA_ARG (Marker, UINTN);
  50     }
  51
  52     VA_END (Marker);
  53     return Result
  54   }
  55
  56 --*/
  57
  58 #ifndef _EFISTDARG_H_
  59 #define _EFISTDARG_H_
  60
  61 #define _EFI_INT_SIZE_OF(n) ((sizeof (n) + sizeof (UINTN) - 1) &~(sizeof (UINTN) - 1))
  62
  63 //
  64 // Also support coding convention rules for var arg macros
  65 //
  66 #ifndef VA_START
  67
  68 typedef CHAR8 *VA_LIST;
  69 #define VA_START(ap, v) (ap = (VA_LIST) & (v) + _EFI_INT_SIZE_OF (v))
  70 #define VA_ARG(ap, t)   (*(t *) ((ap += _EFI_INT_SIZE_OF (t)) - _EFI_INT_SIZE_OF (t)))
  71 #define VA_END(ap)      (ap = (VA_LIST) 0)
  72
  73 #endif
  74
  75 #endif