From 19186a7867fad3775e0c152e232390f4b7b832c8 Mon Sep 17 00:00:00 2001
From: hikari <hikarin522@outlook.jp>
Date: Thu, 9 Dec 2021 11:49:58 +0900
Subject: [PATCH 1/2] fix: Add NextBytes(Span<byte>) to RandomSource

`RandomSource` does not inherit from `NextBytes (Span <byte>)` added in `.NET Core 2.1`, so I added it.
https://docs.microsoft.com/dotnet/api/system.random.nextbytes#System_Random_NextBytes_System_Span_System_Byte__
---
 src/Numerics/Random/RandomSource.cs | 33 +++++++++++++++++++++++++++++
 1 file changed, 33 insertions(+)

diff --git a/src/Numerics/Random/RandomSource.cs b/src/Numerics/Random/RandomSource.cs
index fea612872..0eec22e12 100644
--- a/src/Numerics/Random/RandomSource.cs
+++ b/src/Numerics/Random/RandomSource.cs
@@ -469,6 +469,27 @@ public sealed override void NextBytes(byte[] buffer)
 
             DoSampleBytes(buffer);
         }
+        
+#if NETCOREAPP2_1_OR_GREATER
+        /// <summary>
+        /// Fills the elements of a specified array of bytes with random numbers.
+        /// </summary>
+        /// <param name="buffer">An array of bytes to contain random numbers.</param>
+        public sealed override void NextBytes(Span<byte> buffer)
+        {
+            if (_threadSafe)
+            {
+                lock (_lock)
+                {
+                    DoSampleBytes(buffer);
+                }
+
+                return;
+            }
+
+            DoSampleBytes(buffer);
+        }
+#endif
 
         /// <summary>
         /// Returns a random number between 0.0 and 1.0.
@@ -511,6 +532,18 @@ protected virtual void DoSampleBytes(byte[] buffer)
             }
         }
 
+#if NETCOREAPP2_1_OR_GREATER
+        /// <summary>
+        /// Fills the elements of a specified array of bytes with random numbers in full range, including zero and 255 (<see cref="F:System.Byte.MaxValue"/>).
+        /// </summary>
+        protected virtual void DoSampleBytes(Span<byte> buffer)
+        {
+            var temp = new byte[buffer.Length];
+            DoSampleBytes(temp);
+            temp.CopyTo(buffer);
+        }
+#endif
+
         /// <summary>
         /// Returns a random N-bit signed integer greater than or equal to zero and less than 2^N.
         /// N (bit count) is expected to be greater than zero and less than 32 (not verified).

From 3d398facd71e609d9e6552772a4d366e8c170756 Mon Sep 17 00:00:00 2001
From: hikari <hikarin522@outlook.jp>
Date: Thu, 9 Dec 2021 20:06:48 +0900
Subject: [PATCH 2/2] fixup! fix: Add NextBytes(Span<byte>) to RandomSource

---
 src/Numerics/Numerics.csproj        | 2 +-
 src/Numerics/Random/RandomSource.cs | 6 +++---
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/src/Numerics/Numerics.csproj b/src/Numerics/Numerics.csproj
index 1aa53dd2d..facde6f5e 100644
--- a/src/Numerics/Numerics.csproj
+++ b/src/Numerics/Numerics.csproj
@@ -2,7 +2,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
     <OutputType>Library</OutputType>
-    <TargetFrameworks>net5.0;net461;net48;netstandard2.0</TargetFrameworks>
+    <TargetFrameworks>net5.0;netcoreapp2.1;net461;net48;netstandard2.1;netstandard2.0</TargetFrameworks>
     <AssemblyName>MathNet.Numerics</AssemblyName>
     <RootNamespace>MathNet.Numerics</RootNamespace>
     <IsPackable>true</IsPackable>
diff --git a/src/Numerics/Random/RandomSource.cs b/src/Numerics/Random/RandomSource.cs
index 0eec22e12..9e8cddc40 100644
--- a/src/Numerics/Random/RandomSource.cs
+++ b/src/Numerics/Random/RandomSource.cs
@@ -469,8 +469,8 @@ public sealed override void NextBytes(byte[] buffer)
 
             DoSampleBytes(buffer);
         }
-        
-#if NETCOREAPP2_1_OR_GREATER
+
+#if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER
         /// <summary>
         /// Fills the elements of a specified array of bytes with random numbers.
         /// </summary>
@@ -532,7 +532,7 @@ protected virtual void DoSampleBytes(byte[] buffer)
             }
         }
 
-#if NETCOREAPP2_1_OR_GREATER
+#if NETCOREAPP2_1_OR_GREATER || NETSTANDARD2_1_OR_GREATER
         /// <summary>
         /// Fills the elements of a specified array of bytes with random numbers in full range, including zero and 255 (<see cref="F:System.Byte.MaxValue"/>).
         /// </summary>