From: Hauke Mehrtens <hauke@hauke-m.de>
Date: Wed, 20 Apr 2011 21:31:50 +0000 (+0200)
Subject: compat: add time_to_tm
X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=98d6ba708cc6f295b126dee35a2c96ed23f24148;p=openwrt%2Fstaging%2Fblogic.git

compat: add time_to_tm

time_to_tm is needed in net/mac80211/debugfs_sta.c now.

Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
---

diff --git a/compat/compat-2.6.32.c b/compat/compat-2.6.32.c
index 013150d098fe..0b3af074184b 100644
--- a/compat/compat-2.6.32.c
+++ b/compat/compat-2.6.32.c
@@ -117,3 +117,100 @@ void __dev_addr_unsync(struct dev_addr_list **to, int *to_count,
 }
 EXPORT_SYMBOL_GPL(__dev_addr_unsync);
 
+/*
+ * Nonzero if YEAR is a leap year (every 4 years,
+ * except every 100th isn't, and every 400th is).
+ */
+static int __isleap(long year)
+{
+	return (year) % 4 == 0 && ((year) % 100 != 0 || (year) % 400 == 0);
+}
+
+/* do a mathdiv for long type */
+static long math_div(long a, long b)
+{
+	return a / b - (a % b < 0);
+}
+
+/* How many leap years between y1 and y2, y1 must less or equal to y2 */
+static long leaps_between(long y1, long y2)
+{
+	long leaps1 = math_div(y1 - 1, 4) - math_div(y1 - 1, 100)
+		+ math_div(y1 - 1, 400);
+	long leaps2 = math_div(y2 - 1, 4) - math_div(y2 - 1, 100)
+		+ math_div(y2 - 1, 400);
+	return leaps2 - leaps1;
+}
+
+/* How many days come before each month (0-12). */
+static const unsigned short __mon_yday[2][13] = {
+	/* Normal years. */
+	{0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365},
+	/* Leap years. */
+	{0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335, 366}
+};
+
+#define SECS_PER_HOUR	(60 * 60)
+#define SECS_PER_DAY	(SECS_PER_HOUR * 24)
+
+/**
+ * time_to_tm - converts the calendar time to local broken-down time
+ *
+ * @totalsecs	the number of seconds elapsed since 00:00:00 on January 1, 1970,
+ *		Coordinated Universal Time (UTC).
+ * @offset	offset seconds adding to totalsecs.
+ * @result	pointer to struct tm variable to receive broken-down time
+ */
+void time_to_tm(time_t totalsecs, int offset, struct tm *result)
+{
+	long days, rem, y;
+	const unsigned short *ip;
+
+	days = totalsecs / SECS_PER_DAY;
+	rem = totalsecs % SECS_PER_DAY;
+	rem += offset;
+	while (rem < 0) {
+		rem += SECS_PER_DAY;
+		--days;
+	}
+	while (rem >= SECS_PER_DAY) {
+		rem -= SECS_PER_DAY;
+		++days;
+	}
+
+	result->tm_hour = rem / SECS_PER_HOUR;
+	rem %= SECS_PER_HOUR;
+	result->tm_min = rem / 60;
+	result->tm_sec = rem % 60;
+
+	/* January 1, 1970 was a Thursday. */
+	result->tm_wday = (4 + days) % 7;
+	if (result->tm_wday < 0)
+		result->tm_wday += 7;
+
+	y = 1970;
+
+	while (days < 0 || days >= (__isleap(y) ? 366 : 365)) {
+		/* Guess a corrected year, assuming 365 days per year. */
+		long yg = y + math_div(days, 365);
+
+		/* Adjust DAYS and Y to match the guessed year. */
+		days -= (yg - y) * 365 + leaps_between(y, yg);
+		y = yg;
+	}
+
+	result->tm_year = y - 1900;
+
+	result->tm_yday = days;
+
+	ip = __mon_yday[__isleap(y)];
+	for (y = 11; days < ip[y]; y--)
+		continue;
+	days -= ip[y];
+
+	result->tm_mon = y;
+	result->tm_mday = days + 1;
+}
+EXPORT_SYMBOL(time_to_tm);
+/* source: kernel/time/timeconv.c*/
+
diff --git a/include/linux/compat-2.6.32.h b/include/linux/compat-2.6.32.h
index 321a89ad413c..3506291d2fa0 100644
--- a/include/linux/compat-2.6.32.h
+++ b/include/linux/compat-2.6.32.h
@@ -96,6 +96,34 @@ struct dev_pm_ops name = { \
 
 #define lockdep_assert_held(l)			do { } while (0)
 
+/*
+ * Similar to the struct tm in userspace <time.h>, but it needs to be here so
+ * that the kernel source is self contained.
+ */
+struct tm {
+	/*
+	 * the number of seconds after the minute, normally in the range
+	 * 0 to 59, but can be up to 60 to allow for leap seconds
+	 */
+	int tm_sec;
+	/* the number of minutes after the hour, in the range 0 to 59*/
+	int tm_min;
+	/* the number of hours past midnight, in the range 0 to 23 */
+	int tm_hour;
+	/* the day of the month, in the range 1 to 31 */
+	int tm_mday;
+	/* the number of months since January, in the range 0 to 11 */
+	int tm_mon;
+	/* the number of years since 1900 */
+	long tm_year;
+	/* the number of days since Sunday, in the range 0 to 6 */
+	int tm_wday;
+	/* the number of days since January 1, in the range 0 to 365 */
+	int tm_yday;
+};
+
+void time_to_tm(time_t totalsecs, int offset, struct tm *result);
+
 #endif /* (LINUX_VERSION_CODE < KERNEL_VERSION(2,6,32)) */
 
 #endif /* LINUX_26_32_COMPAT_H */