Respect daylight saving time.

diff --git a/libexfat/time.c b/libexfat/time.c
index 7d2becd..93c1d67 100644 (file)
--- a/libexfat/time.c
+++ b/libexfat/time.c
@@ -151,8 +151,14 @@ void exfat_unix2exfat(time_t unix_time, le16_t* date, le16_t* time,
 void exfat_tzset(void)
 {
        time_t now;
+       struct tm* utc;
 
        tzset();
        now = time(NULL);
-       exfat_timezone = mktime(gmtime(&now)) - now;
+       utc = gmtime(&now);
+       /* gmtime() always sets tm_isdst to 0 because daylight savings never
+          affect UTC. Setting tm_isdst to -1 makes mktime() to determine whether
+          summer time is in effect. */
+       utc->tm_isdst = -1;
+       exfat_timezone = mktime(utc) - now;
 }