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| author | Rich Felker <dalias@aerifal.cx> | 2013-06-28 12:38:42 -0400 |
|---|---|---|
| committer | Rich Felker <dalias@aerifal.cx> | 2013-06-28 12:38:42 -0400 |
| commit | aea79190326cf81d6c8ec81ab163137591c6dac8 (patch) | |
| tree | 17132e9af070662887c0b0011c4baddb5c0db1c0 | |
| parent | 062446a85db9b58b4900df82e17cb8c07ec50453 (diff) | |
| download | musl-aea79190326cf81d6c8ec81ab163137591c6dac8.tar.gz musl-aea79190326cf81d6c8ec81ab163137591c6dac8.tar.xz musl-aea79190326cf81d6c8ec81ab163137591c6dac8.zip | |
implement week-based-year year numbers in strftime
in the process, I refactored the week-number code so it can be used by the week-based-year formats to determine year adjustments at the boundary values. this also improves indention/code readability.
| -rw-r--r-- | src/time/strftime.c | 61 |
1 files changed, 34 insertions, 27 deletions
diff --git a/src/time/strftime.c b/src/time/strftime.c index b60197df..57687058 100644 --- a/src/time/strftime.c +++ b/src/time/strftime.c @@ -17,6 +17,32 @@ static int is_leap(int y) return !(y%4) && ((y%100) || !(y%400)); } +static int week_num(const struct tm *tm) +{ + int val = (tm->tm_yday + 7 - (tm->tm_wday+6)%7) / 7; + /* If 1 Jan is just 1-3 days past Monday, + * the previous week is also in this year. */ + if ((tm->tm_wday - tm->tm_yday - 2 + 371) % 7 <= 2) + val++; + if (!val) { + val = 52; + /* If 31 December of prev year a Thursday, + * or Friday of a leap year, then the + * prev year has 53 weeks. */ + int dec31 = (tm->tm_wday - tm->tm_yday - 1 + 7) % 7; + if (dec31 == 4 || (dec31 == 5 && is_leap(tm->tm_year%400-1))) + val++; + } else if (val == 53) { + /* If 1 January is not a Thursday, and not + * a Wednesday of a leap year, then this + * year has only 52 weeks. */ + int jan1 = (tm->tm_wday - tm->tm_yday + 371) % 7; + if (jan1 != 4 && (jan1 != 3 || !is_leap(tm->tm_year))) + val = 1; + } + return val; +} + size_t strftime(char *restrict s, size_t n, const char *restrict f, const struct tm *restrict tm) { nl_item item; @@ -67,14 +93,15 @@ do_fmt: fmt = "%Y-%m-%d"; goto recu_strftime; case 'g': - // FIXME - val = 0; //week_based_year(tm)%100; - fmt = "%02d"; - goto number; case 'G': - // FIXME - val = 0; //week_based_year(tm); fmt = "%04d"; + val = tm->tm_year + 1900; + if (tm->tm_yday < 3 && week_num(tm) != 1) val--; + else if (tm->tm_yday > 360 && week_num(tm) == 1) val++; + if (*f=='g') { + fmt = "%02d"; + val %= 100; + } goto number; case 'H': val = tm->tm_hour; @@ -133,27 +160,7 @@ do_fmt: fmt = "%02d"; goto number; case 'V': - val = (tm->tm_yday + 7 - (tm->tm_wday+6)%7) / 7; - /* If 1 Jan is just 1-3 days past Monday, - * the previous week is also in this year. */ - if ((tm->tm_wday - tm->tm_yday - 2 + 371) % 7 <= 2) - val++; - if (!val) { - val = 52; - /* If 31 December of prev year a Thursday, - * or Friday of a leap year, then the - * prev year has 53 weeks. */ - int dec31 = (tm->tm_wday - tm->tm_yday - 1 + 7) % 7; - if (dec31 == 4 || (dec31 == 5 && is_leap(tm->tm_year%400-1))) - val++; - } else if (val == 53) { - /* If 1 January is not a Thursday, and not - * a Wednesday of a leap year, then this - * year has only 52 weeks. */ - int jan1 = (tm->tm_wday - tm->tm_yday + 371) % 7; - if (jan1 != 4 && (jan1 != 3 || !is_leap(tm->tm_year))) - val = 1; - } + val = week_num(tm); fmt = "%02d"; goto number; case 'w': |