1 files changed, 67 insertions, 0 deletions
diff --git a/src/csharp/GrpcCore/Internal/Timespec.cs b/src/csharp/GrpcCore/Internal/Timespec.cs
new file mode 100644
index 0000000000..8ffaf70bbf
--- /dev/null
+++ b/src/csharp/GrpcCore/Internal/Timespec.cs
@@ -0,0 +1,67 @@
+using System;
+using System.Runtime.InteropServices;
+using System.Threading;
+
+namespace Google.GRPC.Core.Internal
+{
+	/// <summary>
+	/// gpr_timespec from grpc/support/time.h
+	/// </summary>
+	[StructLayout(LayoutKind.Sequential)]
+	internal struct Timespec
+	{
+        const int nanosPerSecond = 1000 * 1000 * 1000;
+        const int nanosPerTick = 100;
+
+        [DllImport("libgpr.so")]
+        static extern Timespec gpr_now();
+
+		// TODO: this only works on 64bit linux, can we autoselect the right size of ints?
+		// perhaps using IntPtr would work.
+		public System.Int64 tv_sec;
+		public System.Int64 tv_nsec;
+
+		/// <summary>
+		/// Timespec a long time in the future.
+		/// </summary>
+		public static Timespec InfFuture
+		{
+			get
+			{
+				// TODO: set correct value based on the length of the struct
+				return new Timespec { tv_sec = Int32.MaxValue, tv_nsec = 0 };
+			}
+		}
+
+        public static Timespec Now
+        {
+            get
+            {
+                return gpr_now();
+            }
+        }
+
+        /// <summary>
+        /// Creates a GPR deadline from current instant and given timeout.
+        /// </summary>
+        /// <returns>The from timeout.</returns>
+        public static Timespec DeadlineFromTimeout(TimeSpan timeout) {
+            if (timeout == Timeout.InfiniteTimeSpan)
+            {
+                return Timespec.InfFuture;
+            }
+            return Timespec.Now.Add(timeout);
+        }
+
+        public Timespec Add(TimeSpan timeSpan) {
+            long nanos = tv_nsec + (timeSpan.Ticks % TimeSpan.TicksPerSecond) * nanosPerTick;
+            long overflow_sec = (nanos > nanosPerSecond) ? 1 : 0;
+
+            Timespec result;
+            result.tv_nsec = nanos % nanosPerSecond;
+            result.tv_sec = tv_sec + (timeSpan.Ticks / TimeSpan.TicksPerSecond) + overflow_sec; 
+            return result;
+        }
+	}
+}
+