common/include/tvdiff.h

   1 /* nbdkit
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  32
  33 #ifndef NBDKIT_TVDIFF_H
  34 #define NBDKIT_TVDIFF_H
  35
  36 /* Compute struct timeval differences. */
  37
  38 #include <config.h>
  39
  40 #include <sys/time.h>
  41
  42 /* Return the number of µs (microseconds) in y - x. */
  43 static inline int64_t
  44 tvdiff_usec (const struct timeval *x, const struct timeval *y)
  45 {
  46   int64_t usec;
  47
  48   usec = (y->tv_sec - x->tv_sec) * 1000000;
  49   usec += y->tv_usec - x->tv_usec;
  50   return usec;
  51 }
  52
  53 /* Return timeval difference as another struct timeval. z = y - x. */
  54 static inline void
  55 subtract_timeval (const struct timeval *x, const struct timeval *y,
  56                   struct timeval *z)
  57 {
  58   int64_t usec = tvdiff_usec (x, y);
  59
  60   z->tv_sec = usec / 1000000;
  61   z->tv_usec = usec % 1000000;
  62 }
  63
  64 #endif /* NBDKIT_TVDIFF_H */