libcamera: utils: Add helper class for std::chrono::duration

A new utils::Duration class is defined to represent a std::chrono::duration type
with double precision nanosecond timebase. Using a double minimises the loss of
precision when converting timebases. This helper class may be used by IPAs to
represent variables such as frame durations and exposure times.

An operator << overload is defined to help with displaying utils::Duration value
in stream objects. Currently, this will display the duration value in
microseconds.

Signed-off-by: Naushir Patuck <naush@raspberrypi.com>
Reviewed-by: David Plowman <david.plowman@raspberrypi.com>
Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

1 files changed, 45 insertions, 0 deletions

diff --git a/test/utils.cpp b/test/utils.cpp
index 7e24c71e..f170ae4c 100644
--- a/test/utils.cpp
+++ b/test/utils.cpp
@@ -20,6 +20,7 @@
 
 using namespace std;
 using namespace libcamera;
+using namespace std::literals::chrono_literals;
 
 class UtilsTest : public Test
 {
@@ -128,6 +129,46 @@ protected:
 		return TestPass;
 	}
 
+	int testDuration()
+	{
+		std::ostringstream os;
+		utils::Duration exposure;
+		double ratio;
+
+		exposure = 25ms + 25ms;
+		if (exposure.get<std::micro>() != 50000.0) {
+			cerr << "utils::Duration failed to return microsecond count";
+			return TestFail;
+		}
+
+		exposure = 1.0s / 4;
+		if (exposure != 250ms) {
+			cerr << "utils::Duration failed scalar divide test";
+			return TestFail;
+		}
+
+		exposure = 5000.5us;
+		if (!exposure) {
+			cerr << "utils::Duration failed boolean test";
+			return TestFail;
+		}
+
+		os << exposure;
+		if (os.str() != "5000.50us") {
+			cerr << "utils::Duration operator << failed";
+			return TestFail;
+		}
+
+		exposure = 100ms;
+		ratio = exposure / 25ms;
+		if (ratio != 4.0) {
+			cerr << "utils::Duration failed ratio test";
+			return TestFail;
+		}
+
+		return TestPass;
+	}
+
 	int run()
 	{
 		/* utils::hex() test. */
@@ -236,6 +277,10 @@ protected:
 		if (testEnumerate() != TestPass)
 			return TestFail;
 
+		/* utils::Duration test. */
+		if (testDuration() != TestPass)
+			return TestFail;
+
 		return TestPass;
 	}
 };