src/timeval_math.c

   1 #include "timeval_math.h"
   2
   3 #define US_PER_SECOND 1000000
   4
   5 void
   6 timeval_sub(struct timeval t1, struct timeval t2, struct timeval *res)
   7 {
   8         res->tv_usec = t2.tv_usec - t1.tv_usec;
   9         res->tv_sec  = t2.tv_sec - t1.tv_sec;
  10         if (res->tv_sec > 0 && res->tv_usec < 0) {
  11                 res->tv_usec += US_PER_SECOND;
  12                 res->tv_sec--;
  13         } else if (res->tv_sec < 0 && res->tv_usec > 0) {
  14                 res->tv_usec -= US_PER_SECOND;
  15                 res->tv_sec++;
  16         }
  17 }
  18
  19 void
  20 timeval_add(struct timeval t1, struct timeval t2, struct timeval *res)
  21 {
  22         res->tv_usec = t2.tv_usec + t1.tv_usec;
  23         res->tv_sec  = t2.tv_sec + t1.tv_sec;
  24         if (res->tv_usec >= US_PER_SECOND) {
  25                 res->tv_usec -= US_PER_SECOND;
  26                 res->tv_sec++;
  27         } else if (res->tv_usec <= -US_PER_SECOND) {
  28                 res->tv_usec += US_PER_SECOND;
  29                 res->tv_sec--;
  30         }
  31 }
  32
  33 int
  34 timeval_cmp(struct timeval t1, struct timeval t2)
  35 {
  36         if (t1.tv_sec < t2.tv_sec) {
  37                 return -1;
  38         } else if (t1.tv_sec > t2.tv_sec) {
  39                 return +1;
  40         } else if (t1.tv_usec < t2.tv_usec) {
  41                 return -1;
  42         } else if (t1.tv_usec > t2.tv_usec) {
  43                 return +1;
  44         } else {
  45                 return 0;
  46         }
  47 }