Add nstime_ns_since which obtains the duration since the input time.

This commit is contained in:
Qi Wang 2021-12-20 14:39:24 -08:00 committed by Qi Wang
parent cafe9a3158
commit 310af725b0
3 changed files with 42 additions and 0 deletions

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@ -35,6 +35,7 @@ void nstime_isubtract(nstime_t *time, uint64_t subtrahend);
void nstime_imultiply(nstime_t *time, uint64_t multiplier);
void nstime_idivide(nstime_t *time, uint64_t divisor);
uint64_t nstime_divide(const nstime_t *time, const nstime_t *divisor);
uint64_t nstime_ns_since(const nstime_t *past);
typedef bool (nstime_monotonic_t)(void);
extern nstime_monotonic_t *JET_MUTABLE nstime_monotonic;

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@ -158,6 +158,19 @@ nstime_divide(const nstime_t *time, const nstime_t *divisor) {
return time->ns / divisor->ns;
}
/* Returns time since *past, w/o updating *past. */
uint64_t
nstime_ns_since(const nstime_t *past) {
nstime_assert_initialized(past);
nstime_t now;
nstime_copy(&now, past);
nstime_update(&now);
assert(nstime_compare(&now, past) >= 0);
return now.ns - past->ns;
}
#ifdef _WIN32
# define NSTIME_MONOTONIC true
static void

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@ -201,6 +201,33 @@ TEST_BEGIN(test_nstime_divide) {
}
TEST_END
void
test_nstime_since_once(nstime_t *t) {
nstime_t old_t;
nstime_copy(&old_t, t);
uint64_t ns_since = nstime_ns_since(t);
nstime_update(t);
nstime_t new_t;
nstime_copy(&new_t, t);
nstime_subtract(&new_t, &old_t);
expect_u64_ge(nstime_ns(&new_t), ns_since,
"Incorrect time since result");
}
TEST_BEGIN(test_nstime_ns_since) {
nstime_t t;
nstime_init_update(&t);
for (uint64_t i = 0; i < 10000; i++) {
/* Keeps updating t and verifies ns_since is valid. */
test_nstime_since_once(&t);
}
}
TEST_END
TEST_BEGIN(test_nstime_monotonic) {
nstime_monotonic();
}
@ -220,5 +247,6 @@ main(void) {
test_nstime_imultiply,
test_nstime_idivide,
test_nstime_divide,
test_nstime_ns_since,
test_nstime_monotonic);
}