Add UTCOffset class.

5 files changed, 173 insertions, 23 deletions

diff --git a/src/local_time.cc b/src/local_time.cc
index ad2291f9..8d48e037 100644
--- a/src/local_time.cc
+++ b/src/local_time.cc
@@ -103,11 +103,10 @@ LocalTime::set (boost::posix_time::ptime t)
 }
 
 
-LocalTime::LocalTime (boost::posix_time::ptime t, int tz_hour, int tz_minute)
+LocalTime::LocalTime(boost::posix_time::ptime t, UTCOffset offset)
 {
 	set (t);
-	_tz_hour = tz_hour;
-	_tz_minute = tz_minute;
+	_offset = offset;
 }
 
 
@@ -119,8 +118,7 @@ LocalTime::set_local_time_zone ()
 	auto const now = boost::date_time::c_local_adjustor<boost::posix_time::ptime>::utc_to_local (utc_now);
 	auto offset = now - utc_now;
 
-	_tz_hour = offset.hours ();
-	_tz_minute = offset.minutes ();
+	_offset = { static_cast<int>(offset.hours()), static_cast<int>(offset.minutes()) };
 }
 
 
@@ -172,12 +170,13 @@ LocalTime::LocalTime (string s)
 	_minute = lexical_cast<int>(s.substr(14, 2));
 	_second = lexical_cast<int>(s.substr(17, 2));
 	_millisecond = with_millisecond ? lexical_cast<int>(s.substr(20, 3)) : 0;
-	_tz_hour = with_tz ? lexical_cast<int>(s.substr(tz_pos + 1, 2)) : 0;
-	_tz_minute = with_tz ? lexical_cast<int>(s.substr(tz_pos + 4, 2)) : 0;
+
+	_offset.set_hour(with_tz ? lexical_cast<int>(s.substr(tz_pos + 1, 2)) : 0);
+	_offset.set_minute(with_tz ? lexical_cast<int>(s.substr(tz_pos + 4, 2)) : 0);
 
 	if (with_tz && s[tz_pos] == '-') {
-		_tz_hour = -_tz_hour;
-		_tz_minute = -_tz_minute;
+		_offset.set_hour(-_offset.hour());
+		_offset.set_minute(-_offset.minute());
 	}
 }
 
@@ -189,7 +188,7 @@ LocalTime::as_string (bool with_millisecond) const
 	snprintf (
 		buffer, sizeof (buffer),
 		"%sT%s%s%02d:%02d",
-		date().c_str(), time_of_day(true, with_millisecond).c_str(), (_tz_hour >= 0 ? "+" : "-"), abs (_tz_hour), abs(_tz_minute)
+		date().c_str(), time_of_day(true, with_millisecond).c_str(), (_offset.hour() >= 0 ? "+" : "-"), abs(_offset.hour()), abs(_offset.minute())
 		);
 	return buffer;
 }
@@ -268,7 +267,7 @@ LocalTime::operator== (LocalTime const & other) const
 {
 	return _year == other._year && _month == other._month && _day == other._day &&
 		_hour == other._hour && _second == other._second && _millisecond == other._millisecond &&
-		_tz_hour == other._tz_hour && _tz_minute == other._tz_minute;
+		_offset == other._offset;
 }
 
 
@@ -320,7 +319,8 @@ LocalTime::from_asn1_utc_time (string time)
 	}
 	t._year += 1900;
 
-	t._tz_hour = t._tz_minute = t._millisecond = 0;
+	t._millisecond = 0;
+	t._offset = {};
 
 	return t;
 }
@@ -332,7 +332,8 @@ LocalTime::from_asn1_generalized_time (string time)
 	LocalTime t;
 	sscanf(time.c_str(), "%4d%2d%2d%2d%2d%2d", &t._year, &t._month, &t._day, &t._hour, &t._minute, &t._second);
 
-	t._tz_hour = t._tz_minute = t._millisecond = 0;
+	t._millisecond = 0;
+	t._offset = {};
 
 	return t;
 }
diff --git a/src/local_time.h b/src/local_time.h
index c0d8a35e..aacd7728 100644
--- a/src/local_time.h
+++ b/src/local_time.h
@@ -41,6 +41,7 @@
 #define LIBDCP_LOCAL_TIME_H
 
 
+#include "utc_offset.h"
 #include <boost/date_time/posix_time/posix_time.hpp>
 #include <string>
 
@@ -73,11 +74,8 @@ public:
 	 */
 	explicit LocalTime (boost::posix_time::ptime);
 
-	/** Construct a LocalTime from a boost::posix_time::ptime and a time zone offset
-	 *  @param tz_minute Offset from UTC in minutes; if the timezone is behind UTC this may be negative,
-	 *  e.g. -04:30 would have tz_hour=-1 and tz_minute=-30.
-	 */
-	LocalTime (boost::posix_time::ptime, int tz_hour, int tz_minute);
+	/** Construct a LocalTime from a boost::posix_time::ptime and a time zone offset */
+	LocalTime(boost::posix_time::ptime, UTCOffset offset);
 
 	/** @param s A string of the form 2013-01-05T18:06:59[.123][+04:00] */
 	explicit LocalTime (std::string s);
@@ -146,11 +144,7 @@ private:
 	int _second = 0;      ///< second number of the minute (0-59)
 	int _millisecond = 0; ///< millisecond number of the second (0-999)
 
-	int _tz_hour = 0;     ///< hours by which this time is offset from UTC; can be negative
-	/** Minutes by which this time is offset from UTC; if _tz_hour is negative
-	 *  this will be either 0 or negative.
-	 */
-	int _tz_minute = 0;
+	UTCOffset _offset;
 };
 
 
diff --git a/src/utc_offset.cc b/src/utc_offset.cc
new file mode 100644
index 00000000..d9abcd60
--- /dev/null
+++ b/src/utc_offset.cc
@@ -0,0 +1,69 @@
+/*
+    Copyright (C) 2014-2021 Carl Hetherington <cth@carlh.net>
+
+    This file is part of libdcp.
+
+    libdcp 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 2 of the License, or
+    (at your option) any later version.
+
+    libdcp is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    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 libdcp.  If not, see <http://www.gnu.org/licenses/>.
+
+    In addition, as a special exception, the copyright holders give
+    permission to link the code of portions of this program with the
+    OpenSSL library under certain conditions as described in each
+    individual source file, and distribute linked combinations
+    including the two.
+
+    You must obey the GNU General Public License in all respects
+    for all of the code used other than OpenSSL.  If you modify
+    file(s) with this exception, you may extend this exception to your
+    version of the file(s), but you are not obligated to do so.  If you
+    do not wish to do so, delete this exception statement from your
+    version.  If you delete this exception statement from all source
+    files in the program, then also delete it here.
+*/
+
+
+#include "dcp_assert.h"
+#include "utc_offset.h"
+
+
+using namespace dcp;
+
+
+void
+UTCOffset::set_hour(int hour)
+{
+	DCP_ASSERT(hour >= -11 && hour <= 12);
+	_hour = hour;
+}
+
+
+void
+UTCOffset::set_minute(int minute)
+{
+	DCP_ASSERT(minute >= -30 && minute <= 30);
+	_minute = minute;
+}
+
+
+bool
+dcp::operator==(UTCOffset const& a, UTCOffset const& b)
+{
+	return a.hour() == b.hour() && a.minute() == b.minute();
+}
+
+
+bool
+dcp::operator!=(UTCOffset const& a, UTCOffset const& b)
+{
+	return a.hour() != b.hour() || a.minute() != b.minute();
+}
diff --git a/src/utc_offset.h b/src/utc_offset.h
new file mode 100644
index 00000000..b29e07cf
--- /dev/null
+++ b/src/utc_offset.h
@@ -0,0 +1,84 @@
+/*
+    Copyright (C) 2014-2021 Carl Hetherington <cth@carlh.net>
+
+    This file is part of libdcp.
+
+    libdcp 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 2 of the License, or
+    (at your option) any later version.
+
+    libdcp is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    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 libdcp.  If not, see <http://www.gnu.org/licenses/>.
+
+    In addition, as a special exception, the copyright holders give
+    permission to link the code of portions of this program with the
+    OpenSSL library under certain conditions as described in each
+    individual source file, and distribute linked combinations
+    including the two.
+
+    You must obey the GNU General Public License in all respects
+    for all of the code used other than OpenSSL.  If you modify
+    file(s) with this exception, you may extend this exception to your
+    version of the file(s), but you are not obligated to do so.  If you
+    do not wish to do so, delete this exception statement from your
+    version.  If you delete this exception statement from all source
+    files in the program, then also delete it here.
+*/
+
+
+#ifndef LIBDCP_UTC_OFFSET_H
+#define LIBDCP_UTC_OFFSET_H
+
+
+namespace dcp {
+
+
+class UTCOffset
+{
+public:
+	UTCOffset() {}
+	UTCOffset(int hour, int minute)
+		: _hour(hour)
+		, _minute(minute)
+	{}
+
+	int hour() const {
+		return _hour;
+	}
+
+	int minute() const {
+		return _minute;
+	}
+
+	void set_hour(int hour);
+	void set_minute(int hour);
+
+private:
+	/** offset such that the equivalent time in UTC can be calculated by
+	 *  doing local_time - (_hour, _minute).  For example:
+	 *  local time    UTC    _hour    _minute
+	 *       09:00  10:00       -1          0
+	 *       09:00  10:30       -1        -30
+	 *       03:00  02:00        1          0
+	 *       03:00  01:30        1         30
+	 */
+	int _hour = 0;
+	int _minute = 0;
+};
+
+
+bool operator==(UTCOffset const& a, UTCOffset const& b);
+bool operator!=(UTCOffset const& a, UTCOffset const& b);
+
+
+}
+
+
+#endif
+
diff --git a/src/wscript b/src/wscript
index e74c3241..39e3351d 100644
--- a/src/wscript
+++ b/src/wscript
@@ -116,6 +116,7 @@ def build(bld):
              subtitle_string.cc
              transfer_function.cc
              types.cc
+             utc_offset.cc
              util.cc
              verify.cc
              verify_j2k.cc
@@ -215,6 +216,7 @@ def build(bld):
               subtitle_string.h
               transfer_function.h
               types.h
+              utc_offset.h
               util.h
               verify.h
               verify_j2k.h