Added make_time(), which converts a udf_timestamp() to a time_t.

git-svn-id: file:///srv/svn/repos/haiku/trunk/current@4231 a95241bf-73f2-0310-859d-f6bbb57e9c96

src/add-ons/kernel/file_systems/udf/Utils.cpp

@@ -12,6 +12,15 @@
 
 #include "Utils.h"
 
+extern "C" {
+	#ifndef _IMPEXP_KERNEL
+	#	define _IMPEXP_KERNEL
+	#endif
+	
+	extern int32 timezone_offset;
+}
+
+
 namespace Udf {
 
 udf_long_address
@@ -32,4 +41,58 @@ to_vnode_id(udf_long_address address)
 	return (address.block() << 16) | (address.partition());
 }
 
+time_t
+make_time(udf_timestamp &timestamp)
+{
+	DEBUG_INIT_ETC(CF_HELPER | CF_HIGH_VOLUME, NULL, ("timestamp: (tnt: 0x%x, type: %d, timezone: %d = 0x%x, year: %d, " 
+	           "month: %d, day: %d, hour: %d, minute: %d, second: %d)", timestamp.type_and_timezone(),
+	           timestamp.type(), timestamp.timezone(),
+	            timestamp.timezone(),timestamp.year(),
+	           timestamp.month(), timestamp.day(), timestamp.hour(), timestamp.minute(), timestamp.second()));
+
+	time_t result = 0;
+	
+	if (timestamp.year() >= 1970) {
+		const int monthLengths[12] = { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
+
+		int year = timestamp.year();
+		int month = timestamp.month();
+		int day = timestamp.day();
+		int hour = timestamp.hour();
+		int minute = timestamp.minute();
+		int second = timestamp.second();
+
+		// Range check the timezone offset, then round it down
+		// to the nearest hour, since no one I know treats timezones
+		// with a per-minute granularity, and none of the other OSes
+		// I've looked at appear to either.
+		int timezone_offset = timestamp.timezone();
+		if (-1440 > timezone_offset || timezone_offset > 1440)
+			timezone_offset = 0;
+		timezone_offset -= timezone_offset % 60;
+		
+		int previousLeapYears = (year - 1968) / 4;
+		bool isLeapYear = (year - 1968) % 4 == 0;
+		if (isLeapYear)
+			--previousLeapYears;
+		
+		// Years to days
+		result = (year - 1970) * 365 + previousLeapYears;
+		// Months to days
+		for (int i = 0; i < month-1; i++) {
+			result += monthLengths[i];
+		}
+		if (month > 2 && isLeapYear)
+			++result;
+		// Days to hours
+		result = (result + day - 1) * 24;
+		// Hours to minutes
+		result = (result + hour) * 60 + timezone_offset;
+		// Minutes to seconds
+		result = (result + minute) * 60 + second;		
+	}
+	
+	return result;
+}
+
 } // namespace Udf

src/add-ons/kernel/file_systems/udf/Utils.h

@@ -28,6 +28,8 @@ udf_long_address to_long_address(vnode_id id, uint32 length = 0);
 
 vnode_id to_vnode_id(udf_long_address address);
 
+time_t make_time(udf_timestamp &timestamp);
+
 } // namespace Udf
 
 #endif	// _UDF_UTILS_H