Hi,
Couple things:
- Use additional timespec variables to make our intent more obvious.
Add "elapsed", "utc_offset", and "utc_start".
"roff" is a confusing name, "utc_offset" is better.
Yes, I know the clock is called CLOCK_REALTIME, but that's a
historical accident. Ideally they would have called it CLOCK_UTC
or CLOCK_UNIX. Sigh.
- Before the loop, we only need to compute utc_offset in the -m flag
case.
- Before the loop, we only need to do two clock_gettime(2) calls in
the -m flag case.
- In the loop, we can use the new variables to help clarify what we're
doing:
+ In the -i and -s flag cases we're using an elapsed time for the
timestamp, so compute "elapsed".
+ In the default and -m cases we're using an absolute time for the
timestamp, so (if necessary) compute "now".
- We don't need to call clock_gettime(2) twice in the -i flag case.
Just compute "elapsed" and then assign "now" to "start". Easy.
- I think the pimp my ride joke is cute, but calling the function
"print_timestamp()" is a bit more obvious. It also tells the
reader that there's a side effect.
- Because we always call localtime(3), we can move that call into
print_timestamp() and just pass the timespec as argument.
This makes it clearer where the nanosecond value is coming from,
which in turn makes it clearer that the string "ms" will be exactly
6 bytes in length.
I think "ms" stands for "microseconds", in which case a better name
is "us" or "usecs", but that's outside the scope of this patch.
--
ok?
Index: ts.c
===================================================================
RCS file: /cvs/src/usr.bin/ts/ts.c,v
retrieving revision 1.6
diff -u -p -r1.6 ts.c
--- ts.c 4 Jul 2022 17:29:03 -0000 1.6
+++ ts.c 4 Jul 2022 18:17:20 -0000
@@ -32,7 +32,7 @@ static char *buf;
static char *outbuf;
static size_t bufsize;
-static void fmtfmt(struct tm *, long);
+static void print_timestamp(const struct timespec *);
static void __dead usage(void);
int
@@ -40,8 +40,7 @@ main(int argc, char *argv[])
{
int iflag, mflag, sflag;
int ch, prev;
- struct timespec roff, start, now;
- struct tm *tm;
+ struct timespec elapsed, now, start, utc_offset, utc_start;
clockid_t clock = CLOCK_REALTIME;
if (pledge("stdio", NULL) == -1)
@@ -93,22 +92,28 @@ main(int argc, char *argv[])
if (setenv("TZ", "UTC", 1) == -1)
err(1, "setenv UTC");
- clock_gettime(CLOCK_REALTIME, &roff);
- clock_gettime(clock, &start);
- timespecsub(&roff, &start, &roff);
+ if (clock != CLOCK_REALTIME) {
+ clock_gettime(clock, &start);
+ if (mflag) {
+ clock_gettime(CLOCK_REALTIME, &utc_start);
+ timespecsub(&utc_start, &start, &utc_offset);
+ }
+ } else
+ clock_gettime(CLOCK_REALTIME, &start);
for (prev = '\n'; (ch = getchar()) != EOF; prev = ch) {
if (prev == '\n') {
clock_gettime(clock, &now);
- if (iflag || sflag)
- timespecsub(&now, &start, &now);
- else if (mflag)
- timespecadd(&now, &roff, &now);
- if (iflag)
- clock_gettime(clock, &start);
- if ((tm = localtime(&now.tv_sec)) == NULL)
- err(1, "localtime");
- fmtfmt(tm, now.tv_nsec);
+ if (iflag || sflag) {
+ timespecsub(&now, &start, &elapsed);
+ if (iflag)
+ start = now;
+ print_timestamp(&elapsed);
+ } else {
+ if (mflag)
+ timespecadd(&now, &utc_offset, &now);
+ print_timestamp(&now);
+ }
}
if (putchar(ch) == EOF)
break;
@@ -132,11 +137,15 @@ usage(void)
* so you can format while you format
*/
static void
-fmtfmt(struct tm *tm, long tv_nsec)
+print_timestamp(const struct timespec *ts)
{
+ struct tm *tm;
char *f, ms[7];
- snprintf(ms, sizeof(ms), "%06ld", tv_nsec / 1000);
+ if ((tm = localtime(&ts->tv_sec)) == NULL)
+ err(1, "localtime");
+
+ snprintf(ms, sizeof(ms), "%06ld", ts->tv_nsec / 1000);
strlcpy(buf, format, bufsize);
f = buf;
