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parsedate: tune the date to epoch conversion

By avoiding an unnecessary error check and the temp use of the tm
struct, the time2epoch conversion function gets a little bit faster.
When repeating test 517, the updated version is perhaps 1% faster (on
one particular build on one particular architecture).

Closes #5985
This commit is contained in:
Daniel Stenberg 2020-09-21 12:55:38 +02:00
parent be23839477
commit 2e645e21de
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@ -275,48 +275,21 @@ enum assume {
DATE_TIME DATE_TIME
}; };
/* this is a clone of 'struct tm' but with all fields we don't need or use /*
cut out */ * time2epoch: time stamp to seconds since epoch in GMT time zone. Similar to
struct my_tm { * mktime but for GMT only.
int tm_sec;
int tm_min;
int tm_hour;
int tm_mday;
int tm_mon;
int tm_year; /* full year */
};
/* struct tm to time since epoch in GMT time zone.
* This is similar to the standard mktime function but for GMT only, and
* doesn't suffer from the various bugs and portability problems that
* some systems' implementations have.
*
* Returns 0 on success, otherwise non-zero.
*/ */
static void my_timegm(struct my_tm *tm, time_t *t) static time_t time2epoch(int sec, int min, int hour,
int mday, int mon, int year)
{ {
static const int month_days_cumulative [12] = static const int month_days_cumulative [12] =
{ 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334 }; { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334 };
int month, year, leap_days; int leap_days = year - (mon <= 1);
year = tm->tm_year;
month = tm->tm_mon;
if(month < 0) {
year += (11 - month) / 12;
month = 11 - (11 - month) % 12;
}
else if(month >= 12) {
year -= month / 12;
month = month % 12;
}
leap_days = year - (tm->tm_mon <= 1);
leap_days = ((leap_days / 4) - (leap_days / 100) + (leap_days / 400) leap_days = ((leap_days / 4) - (leap_days / 100) + (leap_days / 400)
- (1969 / 4) + (1969 / 100) - (1969 / 400)); - (1969 / 4) + (1969 / 100) - (1969 / 400));
return ((((time_t) (year - 1970) * 365
*t = ((((time_t) (year - 1970) * 365 + leap_days + month_days_cumulative[mon] + mday - 1) * 24
+ leap_days + month_days_cumulative[month] + tm->tm_mday - 1) * 24 + hour) * 60 + min) * 60 + sec;
+ tm->tm_hour) * 60 + tm->tm_min) * 60 + tm->tm_sec;
} }
/* /*
@ -341,7 +314,6 @@ static int parsedate(const char *date, time_t *output)
int secnum = -1; int secnum = -1;
int yearnum = -1; int yearnum = -1;
int tzoff = -1; int tzoff = -1;
struct my_tm tm;
enum assume dignext = DATE_MDAY; enum assume dignext = DATE_MDAY;
const char *indate = date; /* save the original pointer */ const char *indate = date; /* save the original pointer */
int part = 0; /* max 6 parts */ int part = 0; /* max 6 parts */
@ -533,18 +505,11 @@ static int parsedate(const char *date, time_t *output)
(hournum > 23) || (minnum > 59) || (secnum > 60)) (hournum > 23) || (minnum > 59) || (secnum > 60))
return PARSEDATE_FAIL; /* clearly an illegal date */ return PARSEDATE_FAIL; /* clearly an illegal date */
tm.tm_sec = secnum; /* time2epoch() returns a time_t. time_t is often 32 bits, sometimes even on
tm.tm_min = minnum;
tm.tm_hour = hournum;
tm.tm_mday = mdaynum;
tm.tm_mon = monnum;
tm.tm_year = yearnum;
/* my_timegm() returns a time_t. time_t is often 32 bits, sometimes even on
architectures that feature 64 bit 'long' but ultimately time_t is the architectures that feature 64 bit 'long' but ultimately time_t is the
correct data type to use. correct data type to use.
*/ */
my_timegm(&tm, &t); t = time2epoch(secnum, minnum, hournum, mdaynum, monnum, yearnum);
/* Add the time zone diff between local time zone and GMT. */ /* Add the time zone diff between local time zone and GMT. */
if(tzoff == -1) if(tzoff == -1)