Update ReadFully to use BufferPool + add more efficient ReadFullyAsMemory

Author: mythz

src/ServiceStack.Text/StreamExtensions.cs

@@ -2,6 +2,7 @@
 //License: https://raw.github.com/ServiceStack/ServiceStack/master/license.txt
 
 using System;
+using System.Buffers.Text;
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
@@ -10,6 +11,7 @@
 using System.Threading;
 using System.Threading.Tasks;
 using ServiceStack.Text;
+using ServiceStack.Text.Pools;
 
 namespace ServiceStack
 {
@@ -58,13 +60,9 @@ public static IEnumerable<string> ReadLines(this Stream stream)
         public const int DefaultBufferSize = 8 * 1024;
 
         /// <summary>
-        /// Reads the given stream up to the end, returning the data as a byte
-        /// array.
+        /// Reads the given stream up to the end, returning the data as a byte array.
         /// </summary>
-        public static byte[] ReadFully(this Stream input)
-        {
-            return ReadFully(input, DefaultBufferSize);
-        }
+        public static byte[] ReadFully(this Stream input) => ReadFully(input, DefaultBufferSize);
 
         /// <summary>
         /// Reads the given stream up to the end, returning the data as a byte
@@ -75,7 +73,15 @@ public static byte[] ReadFully(this Stream input, int bufferSize)
             if (bufferSize < 1)
                 throw new ArgumentOutOfRangeException(nameof(bufferSize));
 
-            return ReadFully(input, new byte[bufferSize]);
+            byte[] buffer = BufferPool.GetBuffer(bufferSize);
+            try
+            {
+                return ReadFully(input, buffer);
+            }
+            finally
+            {
+                BufferPool.ReleaseBufferToPool(ref buffer);
+            }
         }
 
         /// <summary>
@@ -110,6 +116,45 @@ public static byte[] ReadFully(this Stream input, byte[] buffer)
             }
         }
 
+        /// <summary>
+        /// Reads the given stream up to the end, returning the MemoryStream Buffer as ReadOnlyMemory&lt;byte&gt;.
+        /// </summary>
+        public static ReadOnlyMemory<byte> ReadFullyAsMemory(this Stream input) => 
+            ReadFullyAsMemory(input, DefaultBufferSize);
+
+        /// <summary>
+        /// Reads the given stream up to the end, returning the MemoryStream Buffer as ReadOnlyMemory&lt;byte&gt;.
+        /// </summary>
+        public static ReadOnlyMemory<byte> ReadFullyAsMemory(this Stream input, int bufferSize)
+        {
+            byte[] buffer = BufferPool.GetBuffer(bufferSize);
+            try
+            {
+                return ReadFullyAsMemory(input, buffer);
+            }
+            finally
+            {
+                BufferPool.ReleaseBufferToPool(ref buffer);
+            }
+        }
+
+        public static ReadOnlyMemory<byte> ReadFullyAsMemory(this Stream input, byte[] buffer)
+        {
+            if (buffer == null)
+                throw new ArgumentNullException(nameof(buffer));
+
+            if (input == null)
+                throw new ArgumentNullException(nameof(input));
+
+            if (buffer.Length == 0)
+                throw new ArgumentException("Buffer has length of 0");
+
+            var ms = new MemoryStream();
+            CopyTo(input, ms, buffer);
+            return ms.GetBufferAsMemory();
+        }
+
+
         /// <summary>
         /// Copies all the data from one stream into another.
         /// </summary>