From b9f05378abe6e96249199fd9ba8e8572665661ea Mon Sep 17 00:00:00 2001
From: Austin Drefke <jdrefke@microsoft.com>
Date: Fri, 26 Jul 2019 10:42:13 -0700
Subject: [PATCH] allow LogData to be called in multi threaded environment

---
 src/HyperLogLog.net/HyperLogLog.net/HyperLogLog.cs | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/src/HyperLogLog.net/HyperLogLog.net/HyperLogLog.cs b/src/HyperLogLog.net/HyperLogLog.net/HyperLogLog.cs
index 242cbe2..063b47c 100644
--- a/src/HyperLogLog.net/HyperLogLog.net/HyperLogLog.cs
+++ b/src/HyperLogLog.net/HyperLogLog.net/HyperLogLog.cs
@@ -9,6 +9,7 @@ public class HyperLogLog
         internal readonly byte[] _registers;
         private readonly HashAlgorithm _hashAlgorithm;
         private readonly IBytesConverter _bytesConverter;
+        private readonly object _hashLock = new object();
 
         #region Constants
 
@@ -108,7 +109,12 @@ private double FastPow2(int x)
         private ulong GetHash(object data)
         {
             var dataBytes = _bytesConverter.GetBytes(data);
-            var hashBytes = _hashAlgorithm.ComputeHash(dataBytes);
+            var hashBytes = new byte[0];
+
+            lock (_hashLock)
+            {
+                hashBytes = _hashAlgorithm.ComputeHash(dataBytes);
+            }
 
             // XORing the hash into 64bits sections is not required - we can just take the first 64 bits
             //ulong hash = 0;