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timedated: use builtins for integer log and exp

This commit is contained in:
Zbigniew Jędrzejewski-Szmek 2014-03-14 21:43:56 -04:00
parent 40b71e89ba
commit 8fe90522fb
3 changed files with 21 additions and 22 deletions
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6
src/shared/util.h
View File

@ -782,6 +782,12 @@ static inline unsigned u32ctz(uint32_t n) {
#endif
}
static inline int log2i(int x) {
assert(x > 0);
return __SIZEOF_INT__ * 8 - __builtin_clz(x) - 1;
}
static inline bool logind_running(void) {
return access("/run/systemd/seats/", F_OK) >= 0;
}

12
src/test/test-util.c
View File

@ -645,6 +645,17 @@ static void test_hexdump(void) {
hexdump(stdout, data, sizeof(data));
}
static void test_log2i(void) {
assert_se(log2i(1) == 0);
assert_se(log2i(2) == 1);
assert_se(log2i(3) == 1);
assert_se(log2i(4) == 2);
assert_se(log2i(32) == 5);
assert_se(log2i(33) == 5);
assert_se(log2i(63) == 5);
assert_se(log2i(INT_MAX) == sizeof(int)*8-2);
}
int main(int argc, char *argv[]) {
log_parse_environment();
log_open();
@ -687,6 +698,7 @@ int main(int argc, char *argv[]) {
test_in_set();
test_writing_tmpfile();
test_hexdump();
test_log2i();
return 0;
}

25
src/timedate/timedate-sntp.c
View File

@ -138,25 +138,6 @@ struct SNTPContext {
static int sntp_arm_timer(SNTPContext *sntp);
static int log2i(int a) {
int exp = 0;
assert(a > 0);
while (a > 0) {
a >>= 1;
exp++;
}
return exp;
}
static double log2d(int a) {
if (a < 0)
return 1.0 / (1UL << - a);
return 1UL << a;
}
static double ntp_ts_to_d(const struct ntp_ts *ts) {
return be32toh(ts->sec) + ((double)be32toh(ts->frac) / UINT_MAX);
}
@ -531,21 +512,21 @@ static int sntp_receive_response(sd_event_source *source, int fd, uint32_t reven
" dest : %f\n"
" offset : %+f sec\n"
" delay : %+f sec\n"
" packet count : %llu\n"
" packet count : %"PRIu64"\n"
" jitter/spike : %f (%s)\n"
" poll interval: %llu\n",
NTP_FIELD_LEAP(ntpmsg->field),
NTP_FIELD_VERSION(ntpmsg->field),
NTP_FIELD_MODE(ntpmsg->field),
ntpmsg->stratum,
log2d(ntpmsg->precision), ntpmsg->precision,
exp2(ntpmsg->precision), ntpmsg->precision,
ntpmsg->stratum == 1 ? ntpmsg->refid : "n/a",
origin - OFFSET_1900_1970,
recv - OFFSET_1900_1970,
trans - OFFSET_1900_1970,
dest - OFFSET_1900_1970,
offset, delay,
(unsigned long long)sntp->packet_count,
sntp->packet_count,
sntp->samples_jitter, spike ? "yes" : "no",
sntp->poll_interval / USEC_PER_SEC);