X-Git-Url: https://git.sven.stormbind.net/?a=blobdiff_plain;f=libexfat%2Ftime.c;h=e2a3b23d631fd7bad127ee979bf62ffe50d8f963;hb=1e7534bbaa34e6c2a8c9809dfcf6588112cbdee4;hp=890930eacbcdca19faef16fca8667458db4940b4;hpb=31c7740425f6fc11cc1f4c4316c659c566d94036;p=sven%2Ffuse-exfat.git

diff --git a/libexfat/time.c b/libexfat/time.c
index 890930e..e2a3b23 100644
--- a/libexfat/time.c
+++ b/libexfat/time.c
@@ -2,11 +2,12 @@
 	time.c (03.02.12)
 	exFAT file system implementation library.
 
-	Copyright (C) 2010-2012  Andrew Nayenko
+	Free exFAT implementation.
+	Copyright (C) 2010-2018  Andrew Nayenko
 
-	This program is free software: you can redistribute it and/or modify
+	This program is free software; you can redistribute it and/or modify
 	it under the terms of the GNU General Public License as published by
-	the Free Software Foundation, either version 3 of the License, or
+	the Free Software Foundation, either version 2 of the License, or
 	(at your option) any later version.
 
 	This program is distributed in the hope that it will be useful,
@@ -14,8 +15,9 @@
 	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 	GNU General Public License for more details.
 
-	You should have received a copy of the GNU General Public License
-	along with this program.  If not, see <http://www.gnu.org/licenses/>.
+	You should have received a copy of the GNU General Public License along
+	with this program; if not, write to the Free Software Foundation, Inc.,
+	51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */
 
 #include "exfat.h"
@@ -51,7 +53,8 @@ static const time_t days_in_year[] =
 	0,   0,  31,  59,  90, 120, 151, 181, 212, 243, 273, 304, 334
 };
 
-time_t exfat_exfat2unix(le16_t date, le16_t time, uint8_t centisec)
+time_t exfat_exfat2unix(le16_t date, le16_t time, uint8_t centisec,
+		uint8_t tzoffset)
 {
 	time_t unix_time = EPOCH_DIFF_SEC;
 	uint16_t ndate = le16_to_cpu(date);
@@ -98,13 +101,18 @@ time_t exfat_exfat2unix(le16_t date, le16_t time, uint8_t centisec)
 	unix_time += centisec / 100;
 
 	/* exFAT stores timestamps in local time, so we correct it to UTC */
-	unix_time += exfat_timezone;
+	if (tzoffset & 0x80)
+		/* lower 7 bits are signed timezone offset in 15 minute increments */
+		unix_time -= (int8_t)(tzoffset << 1) * 15 * 60 / 2;
+	else
+		/* timezone offset not present, assume our local timezone */
+		unix_time += exfat_timezone;
 
 	return unix_time;
 }
 
 void exfat_unix2exfat(time_t unix_time, le16_t* date, le16_t* time,
-		uint8_t* centisec)
+		uint8_t* centisec, uint8_t* tzoffset)
 {
 	time_t shift = EPOCH_DIFF_SEC + exfat_timezone;
 	uint16_t day, month, year;
@@ -144,13 +152,22 @@ void exfat_unix2exfat(time_t unix_time, le16_t* date, le16_t* time,
 	*time = cpu_to_le16(twosec | (min << 5) | (hour << 11));
 	if (centisec)
 		*centisec = (unix_time % 2) * 100;
+
+	/* record our local timezone offset in exFAT (15 minute increment) format */
+	*tzoffset = (uint8_t)(-exfat_timezone / 60 / 15) | 0x80;
 }
 
 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;
 }