src/time.h

   1 #ifndef TIME_H
   2 #define TIME_H
   3
   4 #include "cdefs.h"
   5 #include <stdint.h>
   6 #include <sys/time.h>
   7
   8 /** Time Specification.
   9  *
  10  * Use the inline RTTimeSpecGet/Set to operate on structure this so we
  11  * can easily change the representation if required later.
  12  *
  13  * The current representation is in nanoseconds relative to the unix epoch
  14  * (1970-01-01 00:00:00 UTC). This gives us an approximate span from
  15  * 1678 to 2262 without sacrifying the resolution offered by the various
  16  * host OSes (BSD & LINUX 1ns, NT 100ns).
  17  */
  18 typedef struct RTTIMESPEC
  19 {
  20     /** Nanoseconds since epoch.
  21      * The name is intentially too long to be comfortable to use because you should be
  22      * using inline helpers! */
  23     int64_t     i64NanosecondsRelativeToUnixEpoch;
  24 } RTTIMESPEC;
  25 /** Pointer to a time spec structure. */
  26 typedef RTTIMESPEC *PRTTIMESPEC;
  27 /** Pointer to a const time spec structure. */
  28 typedef const RTTIMESPEC *PCRTTIMESPEC;
  29
  30
  31 /**
  32  * Gets the time as microseconds relative to the unix epoch.
  33  *
  34  * @returns microseconds relative to unix epoch.
  35  * @param   pTime       The time spec to interpret.
  36  */
  37 DECLINLINE(int64_t) RTTimeSpecGetMicro(PCRTTIMESPEC pTime)
  38 {
  39     return pTime->i64NanosecondsRelativeToUnixEpoch / 1000;
  40 }
  41
  42 /**
  43  * Gets the time as POSIX timeval.
  44  *
  45  * @returns pTime.
  46  * @param   pTime       The time spec to interpret.
  47  * @param   pTimeval    Where to store the time as POSIX timeval.
  48  */
  49 DECLINLINE(struct timeval *) RTTimeSpecGetTimeval(PCRTTIMESPEC pTime, struct timeval *pTimeval)
  50 {
  51     int64_t i64 = RTTimeSpecGetMicro(pTime);
  52     int32_t i32Micro = (int32_t)(i64 % 1000000);
  53     i64 /= 1000000;
  54     if (i32Micro < 0)
  55     {
  56         i32Micro += 1000000;
  57         i64++;
  58     }
  59     pTimeval->tv_sec = (time_t)i64;
  60     pTimeval->tv_usec = i32Micro;
  61     return pTimeval;
  62 }
  63
  64 /**
  65  * Sets the time given by seconds relative to the unix epoch.
  66  *
  67  * @returns pTime.
  68  * @param   pTime       The time spec to modify.
  69  * @param   i64Seconds  The new time in seconds.
  70  */
  71 DECLINLINE(PRTTIMESPEC) RTTimeSpecSetSeconds(PRTTIMESPEC pTime, int64_t i64Seconds)
  72 {
  73     pTime->i64NanosecondsRelativeToUnixEpoch = i64Seconds * 1000000000;
  74     return pTime;
  75 }
  76
  77 #endif