Fix exception in conversion from DateTime[Offset] to Timestamp. #296

yfakariya · yfakariya · commit 78b511f1ceb6 · 2018-09-09T16:22:02.000+09:00
If the date time is before Unix epoc and it has subsecond value,
internal divrem operation returns negative remains and it causes exception.
This commit add adjustment for this situation.
diff --git a/src/MsgPack/Timestamp.Conversion.cs b/src/MsgPack/Timestamp.Conversion.cs
@@ -133,6 +133,14 @@ private static void FromOffsetTicks( long ticks, out long unixEpocSeconds, out i
 			long remaining;
 			unixEpocSeconds = DivRem( ticks, SecondsToTicks, out remaining );
 			nanoSeconds = unchecked( ( int )remaining ) * 100;
+			if ( nanoSeconds < 0 )
+			{
+				// In this case, we must adjust these values
+				// from "negative nanosec from nearest larger negative integer"
+				// to "positive nanosec from nearest smaller nagative integer".
+				unixEpocSeconds -= 1;
+				nanoSeconds = ( MaxNanoSeconds + 1 ) + nanoSeconds;
+			}
 		}
 
 		/// <summary>
