src/timing/cl_t_current.cc

   1 // cl_current_time().
   2
   3 #if defined(_WIN32) && !defined(__CYGWIN__)
   4 #include <windows.h> // For GetSystemTimeAsFileTime(), must be included first, sorry.
   5 #endif
   6
   7 // General includes.
   8 #include "base/cl_sysdep.h"
   9
  10 // Specification.
  11 #include "cln/timing.h"
  12
  13
  14 // Implementation.
  15
  16 #include "timing/cl_t_config.h"
  17
  18
  19 #if defined(HAVE_GETTIMEOFDAY)
  20   #include <sys/time.h>
  21 #elif defined(_WIN32) && !defined(__CYGWIN__)
  22   /* <windows.h> included above. */
  23 #else
  24   #include <ctime>
  25 #endif
  26 #include <cerrno>
  27 #include <cstdio>
  28
  29 namespace cln {
  30
  31 const cl_timespec cl_current_time ()
  32 {
  33 #if defined(HAVE_GETTIMEOFDAY)
  34         var struct timeval tv;
  35         if (gettimeofday(&tv,NULL) != 0) {
  36                 perror("gettimeofday");
  37                 tv.tv_sec = 0; tv.tv_usec = 0;
  38         }
  39         return cl_timespec(tv.tv_sec,
  40                            tv.tv_usec * (1000000000/1000000)
  41                           );
  42 #elif defined(_WIN32) && !defined(__CYGWIN__)
  43
  44         /* GetSystemTimePreciseAsFileTime was introduced only in Windows 8.  */
  45         typedef void (WINAPI * GetSystemTimePreciseAsFileTimeFuncType) (FILETIME *lpTime);
  46         static GetSystemTimePreciseAsFileTimeFuncType GetSystemTimePreciseAsFileTimeFunc = NULL;
  47         static BOOL initialized = FALSE;
  48
  49         if (!initialized) {
  50                 HMODULE kernel32 = LoadLibrary ("kernel32.dll");
  51                 if (kernel32 != NULL) {
  52                         GetSystemTimePreciseAsFileTimeFunc =
  53                                 (GetSystemTimePreciseAsFileTimeFuncType) (void *) GetProcAddress (kernel32, "GetSystemTimePreciseAsFileTime");
  54                 }
  55                 initialized = TRUE;
  56         }
  57
  58         FILETIME current_time;
  59
  60         if (GetSystemTimePreciseAsFileTimeFunc != NULL)
  61                 GetSystemTimePreciseAsFileTimeFunc (&current_time);
  62         else
  63                 GetSystemTimeAsFileTime (&current_time);
  64
  65         /* Convert from FILETIME to 'struct timeval'.  */
  66         /* FILETIME: <https://docs.microsoft.com/en-us/windows/desktop/api/minwinbase/ns-minwinbase-filetime> */
  67         ULONGLONG since_1601 =
  68                 ((ULONGLONG) current_time.dwHighDateTime << 32)
  69                 | (ULONGLONG) current_time.dwLowDateTime;
  70         /* Between 1601-01-01 and 1970-01-01 there were 280 normal years and 89 leap
  71            years, in total 134774 days.  */
  72         ULONGLONG since_1970 =
  73                 since_1601 - (ULONGLONG) 134774 * (ULONGLONG) 86400 * (ULONGLONG) 10000000;
  74         ULONGLONG microseconds_since_1970 = since_1970 / (ULONGLONG) 10;
  75         return cl_timespec(microseconds_since_1970 / (ULONGLONG) 1000000,
  76                            (microseconds_since_1970 % (ULONGLONG) 1000000) * (1000000000/1000000)
  77                           );
  78
  79 #else
  80         return cl_timespec(time(NULL),0);
  81 #endif
  82 }
  83
  84 }  // namespace cln