From d6a2bce64a7fa1099e507e1d36b5f1533f42f60f Mon Sep 17 00:00:00 2001 From: Yusuke Endoh Date: Tue, 17 Dec 2019 10:31:20 +0900 Subject: time.c (find_time_t): fix round-to-zero bug `find_time_t` did not work correctly for year older than the Epoch because it used C's integer division (which rounds negative to zero). For example, `TIme.new(1933)` returned a wrong time whose year is 1922 in Asia/Kuala_Lumpur because there is no 00:00:00 1st Jan. 1933 in the time zone. ``` $ TZ=Asia/Kuala_Lumpur ruby -e 'p Time.new(1933)' 1932-12-31 00:00:00 +0700 ``` This change fixes the issue by using `DIV` macro instead of `/`. Now `Time.new(1933)` returns a time in 1933. ``` $ TZ=Asia/Kuala_Lumpur ruby -e 'p Time.new(1933)' 1933-01-01 00:20:00 +0720 ``` [Bug #16159] --- time.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/time.c b/time.c index 25b843e405..ef8a995da4 100644 --- a/time.c +++ b/time.c @@ -3365,12 +3365,12 @@ find_time_t(struct tm *tptr, int utc_p, time_t *tp) *tp = guess_lo + ((tptr->tm_year - tm_lo.tm_year) * 365 + - ((tptr->tm_year-69)/4) - - ((tptr->tm_year-1)/100) + - ((tptr->tm_year+299)/400) - - ((tm_lo.tm_year-69)/4) + - ((tm_lo.tm_year-1)/100) - - ((tm_lo.tm_year+299)/400) + + DIV((tptr->tm_year-69), 4) - + DIV((tptr->tm_year-1), 100) + + DIV((tptr->tm_year+299), 400) - + DIV((tm_lo.tm_year-69), 4) + + DIV((tm_lo.tm_year-1), 100) - + DIV((tm_lo.tm_year+299), 400) + tptr_tm_yday - tm_lo.tm_yday) * 86400 + (tptr->tm_hour - tm_lo.tm_hour) * 3600 + -- cgit v1.2.3