more

src/Renci.SshNet/Common/SshData.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.IO;
 using System.Text;
 
 namespace Renci.SshNet.Common
@@ -143,24 +144,10 @@ protected byte[] ReadBytes()
         /// </summary>
         /// <param name="length">Number of bytes to read.</param>
         /// <returns>An array of bytes that was read from the internal buffer.</returns>
-        /// <exception cref="ArgumentOutOfRangeException"><paramref name="length"/> is greater than the internal buffer size.</exception>
+        /// <exception cref="EndOfStreamException"><paramref name="length"/> is greater than the internal buffer size.</exception>
         protected byte[] ReadBytes(int length)
         {
-            /*
-             * Note that this also prevents allocating non-relevant lengths, such as if length is greater than _data.Count but less than int.MaxValue.
-             * For the nerds, the condition translates to: if (length > data.Count && length < int.MaxValue)
-             * Which probably would cause all sorts of exception, most notably OutOfMemoryException.
-             */
-
-            var data = new byte[length];
-            var bytesRead = _stream.Read(data, 0, length);
-
-            if (bytesRead < length)
-            {
-                throw new ArgumentOutOfRangeException(nameof(length));
-            }
-
-            return data;
+            return _stream.ReadBytes(length);
         }
 
         /// <summary>
@@ -197,7 +184,7 @@ protected bool ReadBoolean()
         /// </returns>
         protected ushort ReadUInt16()
         {
-            return Pack.BigEndianToUInt16(ReadBytes(2));
+            return _stream.ReadUInt16();
         }
 
         /// <summary>
@@ -208,7 +195,7 @@ protected ushort ReadUInt16()
         /// </returns>
         protected uint ReadUInt32()
         {
-            return Pack.BigEndianToUInt32(ReadBytes(4));
+            return _stream.ReadUInt32();
         }
 
         /// <summary>
@@ -219,7 +206,7 @@ protected uint ReadUInt32()
         /// </returns>
         protected ulong ReadUInt64()
         {
-            return Pack.BigEndianToUInt64(ReadBytes(8));
+            return _stream.ReadUInt64();
         }
 
         /// <summary>

src/Renci.SshNet/Common/SshDataStream.cs

@@ -195,6 +195,24 @@ public BigInteger ReadBigInt()
             return new BigInteger(data.Reverse());
         }
 
+        /// <summary>
+        /// Reads the next <see cref="ushort"/> data type from the SSH data stream.
+        /// </summary>
+        /// <returns>
+        /// The <see cref="ushort"/> read from the SSH data stream.
+        /// </returns>
+        public ushort ReadUInt16()
+        {
+#if NET6_0_OR_GREATER
+            Span<byte> bytes = stackalloc byte[2];
+            ReadExactly(bytes);
+            return BinaryPrimitives.ReadUInt16BigEndian(bytes);
+#else
+            var data = ReadBytes(2);
+            return Pack.BigEndianToUInt16(data);
+#endif
+        }
+
         /// <summary>
         /// Reads the next <see cref="uint"/> data type from the SSH data stream.
         /// </summary>
@@ -205,7 +223,7 @@ public uint ReadUInt32()
         {
 #if NET6_0_OR_GREATER
             Span<byte> bytes = stackalloc byte[4];
-            ReadBytes(bytes);
+            ReadExactly(bytes);
             return BinaryPrimitives.ReadUInt32BigEndian(bytes);
 #else
             var data = ReadBytes(4);
@@ -223,7 +241,7 @@ public ulong ReadUInt64()
         {
 #if NET6_0_OR_GREATER
             Span<byte> bytes = stackalloc byte[8];
-            ReadBytes(bytes);
+            ReadExactly(bytes);
             return BinaryPrimitives.ReadUInt64BigEndian(bytes);
 #else
             var data = ReadBytes(8);
@@ -278,33 +296,65 @@ public override byte[] ToArray()
         /// <returns>
         /// An array of bytes that was read from the internal buffer.
         /// </returns>
-        /// <exception cref="ArgumentOutOfRangeException"><paramref name="length"/> is greater than the internal buffer size.</exception>
-        private byte[] ReadBytes(int length)
+        /// <exception cref="EndOfStreamException"><paramref name="length"/> is greater than the internal buffer size.</exception>
+        internal byte[] ReadBytes(int length)
         {
             var data = new byte[length];
-            var bytesRead = Read(data, 0, length);
 
-            if (bytesRead < length)
-            {
-                throw new ArgumentOutOfRangeException(nameof(length), string.Format(CultureInfo.InvariantCulture, "The requested length ({0}) is greater than the actual number of bytes read ({1}).", length, bytesRead));
-            }
+            ReadExactly(data);
 
             return data;
         }
 
-#if NET6_0_OR_GREATER
+#if NET6_0
         /// <summary>
-        /// Fills the specified span with bytes from the internal buffer.
+        /// Reads bytes from the current stream and advances the position within the stream until the <paramref name="buffer"/> is filled.
         /// </summary>
-        /// <param name="destination">The span to fill.</param>
-        /// <exception cref="ArgumentException">The Length of <paramref name="destination"/> is greater than the actual number of bytes read.</exception>
-        private void ReadBytes(Span<byte> destination)
+        /// <param name="buffer">A region of memory. When this method returns, the contents of this region are replaced by the bytes read from the current stream.</param>
+        /// <exception cref="EndOfStreamException">
+        /// The end of the stream is reached before filling the <paramref name="buffer"/>.
+        /// </exception>
+        /// <remarks>
+        /// When <paramref name="buffer"/> is empty, this read operation will be completed without waiting for available data in the stream.
+        /// </remarks>
+        private void ReadExactly(Span<byte> buffer)
         {
-            var bytesRead = Read(destination);
+            var totalRead = 0;
+            while (totalRead < buffer.Length)
+            {
+                var read = Read(buffer.Slice(totalRead));
+                if (read == 0)
+                {
+                    throw new EndOfStreamException();
+                }
+
+                totalRead += read;
+            }
+        }
 
-            if (bytesRead < destination.Length)
+#elif !NET7_0_OR_GREATER
+        /// <summary>
+        /// Reads bytes from the current stream and advances the position within the stream until the <paramref name="buffer"/> is filled.
+        /// </summary>
+        /// <param name="buffer">A region of memory. When this method returns, the contents of this region are replaced by the bytes read from the current stream.</param>
+        /// <exception cref="EndOfStreamException">
+        /// The end of the stream is reached before filling the <paramref name="buffer"/>.
+        /// </exception>
+        /// <remarks>
+        /// When <paramref name="buffer"/> is empty, this read operation will be completed without waiting for available data in the stream.
+        /// </remarks>
+        private void ReadExactly(byte[] buffer)
+        {
+            var totalRead = 0;
+            while (totalRead < buffer.Length)
             {
-                throw new ArgumentException(nameof(destination), string.Format(CultureInfo.InvariantCulture, "The requested length ({0}) is greater than the actual number of bytes read ({1}).", destination.Length, bytesRead));
+                var read = Read(buffer, totalRead, buffer.Length - totalRead);
+                if (read == 0)
+                {
+                    throw new EndOfStreamException();
+                }
+
+                totalRead += read;
             }
         }
 #endif