scc

commit 880f47a7e9feb9c4ac5a5a1fa4def916dc01a2cd
parent dc1a3248ccf389c94c16abf747bcd3348991c6c8
Author: Naveen Narayanan <zerous@simple-cc.org>
Date:   Tue, 29 Sep 2020 10:29:57 +0200

libc: Fix first() in strftime.c

We consider the days of the week to be circular in nature starting
with SUN - 0 through SAT - 6. Hence, we have to consider two use
cases:
1. When the difference between the respective day and the newyear
   doesn't wrap around Eg: day = WED newyear = TUE
2. When the difference between the respective day and the newyear
   wraps around Eg: day = TUE newyear = FRI

This patch fixes the algorithm by considering both usecases.

Diffstat:
M
src/libc/time/strftime.c
 | 
4
+++-

1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/src/libc/time/strftime.c b/src/libc/time/strftime.c
@@ -25,7 +25,9 @@ first(int day, int year)
 	ny = _newyear(year);
 	if (ny == day)
 		return 0;
-	return 7 - (ny + day);
+	if (day - ny < 0)
+		return 7 - (ny - day);
+	return day - ny;
 }