Add TIME_MAX and DURATION_MAX functions (#538)

* Add TIME_MAX and DURATION_MAX functions

* Fix Linting Errors

* change funtion name as per coding style

* change function name as per coding style

* Update duration.cpp

* Update time.cpp

* Update test_duration.cpp

* Update time.hpp

* remove extra empty line

rclcpp/include/rclcpp/duration.hpp

@@ -89,6 +89,10 @@ public:
   Duration
   operator-(const rclcpp::Duration & rhs) const;
 
+  RCLCPP_PUBLIC
+  static Duration
+  max();
+
   RCLCPP_PUBLIC
   Duration
   operator*(double scale) const;

rclcpp/include/rclcpp/time.hpp

@@ -102,6 +102,10 @@ public:
   rcl_time_point_value_t
   nanoseconds() const;
 
+  RCLCPP_PUBLIC
+  static Time
+  max();
+
   /// \return the seconds since epoch as a floating point number.
   /// \warning Depending on sizeof(double) there could be significant precision loss.
   /// When an exact time is required use nanoseconds() instead.

rclcpp/src/rclcpp/duration.cpp

@@ -214,6 +214,12 @@ Duration::nanoseconds() const
   return rcl_duration_.nanoseconds;
 }
 
+Duration
+Duration::max()
+{
+  return Duration(std::numeric_limits<int32_t>::max(), 999999999);
+}
+
 double
 Duration::seconds() const
 {

rclcpp/src/rclcpp/time.cpp

@@ -251,5 +251,11 @@ operator+(const rclcpp::Duration & lhs, const rclcpp::Time & rhs)
   return Time(lhs.nanoseconds() + rhs.nanoseconds(), rhs.get_clock_type());
 }
 
+Time
+Time::max()
+{
+  return Time(std::numeric_limits<int32_t>::max(), 999999999);
+}
+
 
 }  // namespace rclcpp

rclcpp/test/test_duration.cpp

@@ -120,3 +120,10 @@ TEST(TestDuration, negative_duration) {
     EXPECT_EQ(expected_value, assignable_duration.nanoseconds());
   }
 }
+
+TEST(TestDuration, maximum_duration) {
+  rclcpp::Duration max_duration = rclcpp::Duration::max();
+  rclcpp::Duration max(std::numeric_limits<int32_t>::max(), 999999999);
+
+  EXPECT_EQ(max_duration, max);
+}