dep/ACE_wrappers/ace/OS_NS_math.h

   1 // -*- C++ -*-
   2
   3 //=============================================================================
   4 /**
   5  *  @file   OS_NS_math.h
   6  *
   7  *  $Id: OS_NS_math.h 80826 2008-03-04 14:51:23Z wotte $
   8  *
   9  *  @author Douglas C. Schmidt <schmidt@cs.wustl.edu>
  10  *  @author Jesper S. M|ller<stophph@diku.dk>
  11  *  @author and a cast of thousands...
  12  *
  13  *  Originally in OS.h.
  14  */
  15 //=============================================================================
  16
  17 #ifndef ACE_OS_NS_MATH_H
  18 # define ACE_OS_NS_MATH_H
  19
  20 # include /**/ "ace/pre.h"
  21
  22 # include "ace/config-all.h"
  23
  24 # if !defined (ACE_LACKS_PRAGMA_ONCE)
  25 #  pragma once
  26 # endif /* ACE_LACKS_PRAGMA_ONCE */
  27
  28 #include "ace/os_include/os_math.h"
  29
  30 #include /**/ "ace/ACE_export.h"
  31
  32 #if defined (ACE_EXPORT_MACRO)
  33 #  undef ACE_EXPORT_MACRO
  34 #endif
  35 #define ACE_EXPORT_MACRO ACE_Export
  36
  37
  38 /*
  39  * We inline and undef some functions that may be implemented
  40  * as macros on some platforms. This way macro definitions will
  41  * be usable later as there is no way to save the macro definition
  42  * using the pre-processor.
  43  *
  44  */
  45 inline double ace_log2_helper (double x)
  46 {
  47 #if defined (log2)
  48   return log2 (x);
  49 #undef log2
  50 #else
  51 #  if !defined (ACE_LACKS_LOG2)
  52   return ACE_STD_NAMESPACE::log2 (x);
  53 #  else
  54   /*
  55     ==================================================================
  56
  57                 log (x)
  58                    k
  59       log (x) = -------
  60          b      log (b)
  61                    k
  62
  63     meaning the binary logarithm of x using the natural logarithm, for
  64     example, is:
  65
  66
  67                 log (x)
  68                    e
  69       log (x) = -------
  70          2      log (2)
  71                    e
  72
  73     ==================================================================
  74    */
  75
  76   // Precomputed value of 1/log(2.0).  Saves an expensive division and
  77   // computing log(2.0) in each call.
  78   double const _1_ln2 = 1.442695040888963407359924681002;
  79
  80   return log (x) * _1_ln2;
  81 #  endif /* !ACE_LACKS_LOG2 */
  82 #endif /* defined (log2) */
  83 }
  84
  85
  86 ACE_BEGIN_VERSIONED_NAMESPACE_DECL
  87
  88 namespace ACE_OS
  89 {
  90   /// This method computes the largest integral value not greater than x.
  91   ACE_NAMESPACE_INLINE_FUNCTION
  92   double floor (double x);
  93
  94   /// This method computes the smallest integral value not less than x.
  95   ACE_NAMESPACE_INLINE_FUNCTION
  96   double ceil (double x);
  97
  98   /// This method computes the base-2 logarithm of x.
  99   ACE_NAMESPACE_INLINE_FUNCTION
 100   double log2 (double x);
 101
 102 } /* namespace ACE_OS */
 103
 104 ACE_END_VERSIONED_NAMESPACE_DECL
 105
 106 # if defined (ACE_HAS_INLINED_OSCALLS)
 107 #   if defined (ACE_INLINE)
 108 #     undef ACE_INLINE
 109 #   endif /* ACE_INLINE */
 110 #   define ACE_INLINE inline
 111 #   include "ace/OS_NS_math.inl"
 112 # endif /* ACE_HAS_INLINED_OSCALLS */
 113
 114 # include /**/ "ace/post.h"
 115 #endif /* ACE_OS_NS_MATH_H */