diff options
Diffstat (limited to 'ext/date/lib/dow.c')
| -rw-r--r-- | ext/date/lib/dow.c | 18 |
1 files changed, 15 insertions, 3 deletions
diff --git a/ext/date/lib/dow.c b/ext/date/lib/dow.c index 1739566728..4438b723d2 100644 --- a/ext/date/lib/dow.c +++ b/ext/date/lib/dow.c @@ -23,9 +23,21 @@ static int m_table_common[13] = { -1, 0, 3, 3, 6, 1, 4, 6, 2, 5, 0, 3, 5 }; /* 1 = jan */ static int m_table_leap[13] = { -1, 6, 2, 3, 6, 1, 4, 6, 2, 5, 0, 3, 5 }; /* 1 = jan */ +static timelib_sll positive_mod(timelib_sll x, timelib_sll y) +{ + timelib_sll tmp; + + tmp = x % y; + if (tmp < 0) { + tmp += y; + } + + return tmp; +} + static timelib_sll century_value(timelib_sll j) { - return 6 - (j % 4) * 2; + return 6 - positive_mod(j, 4) * 2; } static timelib_sll timelib_day_of_week_ex(timelib_sll y, timelib_sll m, timelib_sll d, int iso) @@ -36,9 +48,9 @@ static timelib_sll timelib_day_of_week_ex(timelib_sll y, timelib_sll m, timelib_ * Julian calendar. We just return the 'wrong' day of week to be * consistent. */ c1 = century_value(y / 100); - y1 = (y % 100); + y1 = positive_mod(y, 100); m1 = timelib_is_leap(y) ? m_table_leap[m] : m_table_common[m]; - dow = (c1 + y1 + m1 + (y1 / 4) + d) % 7; + dow = positive_mod((c1 + y1 + m1 + (y1 / 4) + d), 7); if (iso) { if (dow == 0) { dow = 7; |