Merge branch '8-bug-indexoutofrangeexception-when-using-multi-threaded-consumers' into 'main'

Resolve "Bug: IndexOutOfRangeException when using multi-threaded consumers"

Closes #8

See merge request open-source/dotnet/FastRng!6

FastRng/FastRng.csproj

@@ -3,9 +3,9 @@
     <PropertyGroup>
         <TargetFramework>net7.0</TargetFramework>
         <GeneratePackageOnBuild>true</GeneratePackageOnBuild>
-        <AssemblyVersion>1.1.1</AssemblyVersion>
+        <AssemblyVersion>1.1.2</AssemblyVersion>
-        <FileVersion>1.1.1</FileVersion>
+        <FileVersion>1.1.2</FileVersion>
-        <PackageVersion>1.1.1</PackageVersion>
+        <PackageVersion>1.1.2</PackageVersion>
         <Authors>Thorsten Sommer</Authors>
         <PackageProjectUrl>https://devops.tsommer.org/open-source/dotnet/FastRng</PackageProjectUrl>
         <RepositoryUrl>https://devops.tsommer.org/open-source/dotnet/FastRng</RepositoryUrl>

FastRng/MultiThreadedRng.cs

@@ -295,6 +295,11 @@ public sealed class MultiThreadedRng<TNum> : IRandom<TNum>, IDisposable where TN
         // Made a local copy of the current pointer:
         var myPointer = this.currentBufferPointer;
         
+        // Issue #8: This might happens when the current thread was interrupted by another thread, and
+        // the other thread has already updated the pointer. In this case, we start over again.
+        if (myPointer >= BUFFER_SIZE)
+            goto Start;
+        
         // Increment the pointer for the next thread or call:
         var nextPointer = myPointer + 1;
         
@@ -303,7 +308,7 @@ public sealed class MultiThreadedRng<TNum> : IRandom<TNum>, IDisposable where TN
             goto Start;
 
         //
-        // Case: Success. We updated the pointer and, thus, can use the read number.
+        // Case: Success. We updated the pointer and, thus, can use it to read the number.
         //
         return this.currentBuffer[myPointer];
     }

FastRngTests/MultiThreadedRngTests.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Diagnostics.CodeAnalysis;
 using System.Threading;
+using System.Threading.Tasks;
 using FastRng;
 using FastRng.Distributions;
 using NUnit.Framework;
@@ -223,6 +224,32 @@ public class MultiThreadedRngTests
         Assert.That(lorentzContains1, Is.True, "Lorentz distribution does not contained 1");
     }
     
+    [Test]
+    [Category(TestCategories.LONG_RUNNING)]
+    public void TestMultiThreadedConsumer()
+    {
+        var job1 = Task.Factory.StartNew(Run, TaskCreationOptions.LongRunning);
+        var job2 = Task.Factory.StartNew(Run, TaskCreationOptions.LongRunning);
+        var job3 = Task.Factory.StartNew(Run, TaskCreationOptions.LongRunning);
+        
+        Assert.DoesNotThrowAsync(async () => await job1);
+        Assert.DoesNotThrowAsync(async () => await job2);
+        Assert.DoesNotThrowAsync(async () => await job3);
+        return;
+
+        float Run()
+        {
+            var sum = 0f;
+            var distLorentz = new CauchyLorentzX1<float>(this.rng);
+            for (int i = 0; i < 100_000_000; i++)
+            {
+                sum += distLorentz.NextNumber();
+            }
+
+            return sum;
+        }
+    }
+
     [Test]
     [Category(TestCategories.COVER)]
     [Category(TestCategories.NORMAL)]