date: avoid "X years, 12 months" in relative dates

When relative dates are more than about a year ago, we start writing them as "Y years, M months". At the point where we calculate Y and M, we have the time delta specified as a number of days. We calculate these integers as: Y = days / 365 M = (days % 365 + 15) / 30 This rounds days in the latter half of a month up to the nearest month, so that day 16 is "1 month" (or day 381 is "1 year, 1 month"). We don't round the year at all, though, meaning we can end up with "1 year, 12 months", which is silly; it should just be "2 years". Implement this differently with months of size onemonth = 365/12 so that totalmonths = (long)( (days + onemonth/2)/onemonth ) years = totalmonths / 12 months = totalmonths % 12 In order to do this without floats, we write the first formula as totalmonths = (days*12*2 + 365) / (365*2) Tests and inspiration by Jeff King. Helped-by: Jeff King <peff@peff.net> Signed-off-by: Michael J Gruber <git@drmicha.warpmail.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Michael J Gruber committed Apr 20, 2011 at 11:12 UTC f1e9c548ce45005521892af0299696204ece286b

2 files changed +4 -2

date.c

+3 -2

@@ -129,8 +129,9 @@ const char *show_date_relative(unsigned long time, int tz,

129 }

130 /* Give years and months for 5 years or so */

131 if (diff < 1825) {

132 - unsigned long years = diff / 365;

133 - unsigned long months = (diff % 365 + 15) / 30;

132 + unsigned long totalmonths = (diff * 12 * 2 + 365) / (365 * 2);

133 + unsigned long years = totalmonths / 12;

134 + unsigned long months = totalmonths % 12;

135 int n;

136 n = snprintf(timebuf, timebuf_size, "%lu year%s",

137 years, (years > 1 ? "s" : ""));

t/t0006-date.sh

@@ -25,6 +25,7 @@ check_show 37500000 '1 year, 2 months ago'

25 check_show 55188000 '1 year, 9 months ago'

26 check_show 630000000 '20 years ago'

27 check_show 31449600 '12 months ago'

28 +check_show 62985600 '2 years ago'

30 check_parse() {

31 echo "$1 -> $2" >expect