[PATCH] date: avoid "X years, 12 months" in relative dates
- From
Michael J Gruber <git@drmicha.warpmail.net>
- Date
- Apr 20, 2011, 09:12 UTC
- Message-ID
- <1d0633318ffc778dfcc1c32ecf80fca0327349d6.1303290693.git.git@drmicha.warpmail.net>
- In-Reply-To
- <20110420052435.GA28597@sigill.intra.peff.net>
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> --- date.c | 5 +++-- t/t0006-date.sh | 1 + 2 files changed, 4 insertions(+), 2 deletions(-)
diff --git a/date.c b/date.c index 00f9eb5..cde239c 100644 --- a/date.c +++ b/date.c @@ -129,8 +129,9 @@ const char *show_date_relative(unsigned long time, int tz, } /* Give years and months for 5 years or so */ if (diff < 1825) { - unsigned long years = diff / 365; - unsigned long months = (diff % 365 + 15) / 30; + unsigned long totalmonths = (diff*12*2 + 365)/(365*2); + unsigned long years = totalmonths / 12; + unsigned long months = totalmonths % 12; int n; n = snprintf(timebuf, timebuf_size, "%lu year%s", years, (years > 1 ? "s" : "")); diff --git a/t/t0006-date.sh b/t/t0006-date.sh index 1d4d0a5..f87abb5 100755 --- a/t/t0006-date.sh +++ b/t/t0006-date.sh @@ -25,6 +25,7 @@ check_show 37500000 '1 year, 2 months ago' check_show 55188000 '1 year, 9 months ago' check_show 630000000 '20 years ago' check_show 31449600 '12 months ago' +check_show 62985600 '2 years ago' check_parse() { echo "$1 -> $2" >expect
-- 1.7.5.rc1.312.g1936c