29 lines
1.1 KiB
C
29 lines
1.1 KiB
C
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// From https://github.com/veltzer/demos-linux
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const long long NSEC_PER_SEC=1000000000;
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static inline unsigned long long timespec_diff_nano(struct timespec* x, struct timespec* y) {
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return (x->tv_sec-y->tv_sec)*NSEC_PER_SEC+(x->tv_nsec-y->tv_nsec);
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}
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static inline void timespec_sub(struct timespec* result, struct timespec* x, struct timespec* y) {
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/* Perform the carry for the later subtraction by updating Y. */
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if (x->tv_nsec < y->tv_nsec) {
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int nsec = (y->tv_nsec - x->tv_nsec) / NSEC_PER_SEC + 1;
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y->tv_nsec -= NSEC_PER_SEC * nsec;
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y->tv_sec += nsec;
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}
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if (x->tv_nsec - y->tv_nsec > NSEC_PER_SEC) {
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int nsec = (x->tv_nsec - y->tv_nsec) / NSEC_PER_SEC;
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y->tv_nsec += NSEC_PER_SEC * nsec;
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y->tv_sec -= nsec;
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}
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/* Compute the time remaining to wait. `tv_nsec' is certainly positive. */
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result->tv_sec = x->tv_sec - y->tv_sec;
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result->tv_nsec = x->tv_nsec - y->tv_nsec;
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/* Check that result is not negative */
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// CHECK_ASSERT(x->tv_sec >= y->tv_sec);
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}
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// END From https://github.com/veltzer/demos-linux
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