Only copy the actual number of bytes received to the buffer.

Fixes issue #173.

src/Renci.SshNet.Tests/Classes/Sftp/SftpFileStreamTest_ReadByte_ReadMode_NoDataInWriteBufferAndNoDataInReadBuffer_Eof.cs

@@ -0,0 +1,93 @@
+using System;
+using System.Globalization;
+using System.IO;
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+using Moq;
+using Renci.SshNet.Sftp;
+
+namespace Renci.SshNet.Tests.Classes.Sftp
+{
+    [TestClass]
+    public class SftpFileStreamTest_ReadByte_ReadMode_NoDataInWriteBufferAndNoDataInReadBuffer_Eof
+    {
+        private Mock<ISftpSession> _sftpSessionMock;
+        private string _path;
+        private SftpFileStream _sftpFileStream;
+        private byte[] _handle;
+        private SftpFileAttributes _fileAttributes;
+        private uint _bufferSize;
+        private uint _readBufferSize;
+        private uint _writeBufferSize;
+        private int _actual;
+        private MockSequence _sequence;
+
+        [TestInitialize]
+        public void Setup()
+        {
+            Arrange();
+            Act();
+        }
+
+        public void TearDown()
+        {
+            _sftpSessionMock.InSequence(_sequence)
+                            .Setup(p => p.RequestClose(_handle));
+        }
+
+        protected void Arrange()
+        {
+            var random = new Random();
+            _path = random.Next().ToString(CultureInfo.InvariantCulture);
+            _handle = new[] {(byte) random.Next(byte.MinValue, byte.MaxValue)};
+            _fileAttributes = SftpFileAttributes.Empty;
+            _bufferSize = (uint)random.Next(1, 1000);
+            _readBufferSize = (uint)random.Next(0, 1000);
+            _writeBufferSize = (uint)random.Next(0, 1000);
+
+            _sftpSessionMock = new Mock<ISftpSession>(MockBehavior.Strict);
+
+            _sequence = new MockSequence();
+
+            _sftpSessionMock.InSequence(_sequence)
+                .Setup(p => p.RequestOpen(_path, Flags.Read | Flags.Truncate, true))
+                .Returns(_handle);
+            _sftpSessionMock.InSequence(_sequence).Setup(p => p.RequestFStat(_handle, false))
+                            .Returns(_fileAttributes);
+            _sftpSessionMock.InSequence(_sequence)
+                .Setup(p => p.CalculateOptimalReadLength(_bufferSize))
+                .Returns(_readBufferSize);
+            _sftpSessionMock.InSequence(_sequence)
+                .Setup(p => p.CalculateOptimalWriteLength(_bufferSize, _handle))
+                .Returns(_writeBufferSize);
+            _sftpSessionMock.InSequence(_sequence)
+                .Setup(p => p.IsOpen)
+                .Returns(true);
+            _sftpSessionMock.InSequence(_sequence)
+                .Setup(p => p.RequestRead(_handle, 0UL, _readBufferSize))
+                .Returns(new byte[0]);
+
+            _sftpFileStream = new SftpFileStream(_sftpSessionMock.Object, _path, FileMode.Create, FileAccess.Read, (int)_bufferSize);
+        }
+
+        protected void Act()
+        {
+            _actual = _sftpFileStream.ReadByte();
+        }
+
+        [TestMethod]
+        public void ReadByteShouldReturnMinusOne()
+        {
+            Assert.AreEqual(-1, _actual);
+        }
+
+        [TestMethod]
+        public void PositionShouldReturnZero()
+        {
+            _sftpSessionMock.InSequence(_sequence)
+                            .Setup(p => p.IsOpen)
+                            .Returns(true);
+
+            Assert.AreEqual(0L, _sftpFileStream.Position);
+        }
+    }
+}

src/Renci.SshNet.Tests/Classes/Sftp/SftpFileStreamTest_ReadByte_ReadMode_NoDataInWriteBufferAndNoDataInReadBuffer_LessDataThanReadBufferSizeAvailable.cs

@@ -0,0 +1,100 @@
+using System;
+using System.Globalization;
+using System.IO;
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+using Moq;
+using Renci.SshNet.Abstractions;
+using Renci.SshNet.Sftp;
+
+namespace Renci.SshNet.Tests.Classes.Sftp
+{
+    /// <summary>
+    /// Test for issue #173.
+    /// </summary>
+    [TestClass]
+    public class SftpFileStreamTest_ReadByte_ReadMode_NoDataInWriteBufferAndNoDataInReadBuffer_LessDataThanReadBufferSizeAvailable
+    {
+        private Mock<ISftpSession> _sftpSessionMock;
+        private string _path;
+        private SftpFileStream _sftpFileStream;
+        private byte[] _handle;
+        private SftpFileAttributes _fileAttributes;
+        private uint _bufferSize;
+        private uint _readBufferSize;
+        private uint _writeBufferSize;
+        private int _actual;
+        private byte[] _data;
+        private MockSequence _sequence;
+
+        [TestInitialize]
+        public void Setup()
+        {
+            Arrange();
+            Act();
+        }
+
+        public void TearDown()
+        {
+            _sftpSessionMock.InSequence(_sequence)
+                            .Setup(p => p.RequestClose(_handle));
+        }
+
+        protected void Arrange()
+        {
+            var random = new Random();
+            _path = random.Next().ToString(CultureInfo.InvariantCulture);
+            _handle = new[] { (byte)random.Next(byte.MinValue, byte.MaxValue) };
+            _fileAttributes = SftpFileAttributes.Empty;
+            _bufferSize = (uint) random.Next(5, 1000);
+            _readBufferSize = (uint) random.Next(10, 100);
+            _writeBufferSize = (uint) random.Next(10, 100);
+            _data = new byte[_readBufferSize - 2];
+            CryptoAbstraction.GenerateRandom(_data);
+
+            _sftpSessionMock = new Mock<ISftpSession>(MockBehavior.Strict);
+
+            _sequence = new MockSequence();
+
+            _sftpSessionMock.InSequence(_sequence)
+                .Setup(p => p.RequestOpen(_path, Flags.Read | Flags.Truncate, true))
+                .Returns(_handle);
+            _sftpSessionMock.InSequence(_sequence).Setup(p => p.RequestFStat(_handle, false))
+                            .Returns(_fileAttributes);
+            _sftpSessionMock.InSequence(_sequence)
+                .Setup(p => p.CalculateOptimalReadLength(_bufferSize))
+                .Returns(_readBufferSize);
+            _sftpSessionMock.InSequence(_sequence)
+                .Setup(p => p.CalculateOptimalWriteLength(_bufferSize, _handle))
+                .Returns(_writeBufferSize);
+            _sftpSessionMock.InSequence(_sequence)
+                .Setup(p => p.IsOpen)
+                .Returns(true);
+            _sftpSessionMock.InSequence(_sequence)
+                .Setup(p => p.RequestRead(_handle, 0UL, _readBufferSize))
+                .Returns(_data);
+
+            _sftpFileStream = new SftpFileStream(_sftpSessionMock.Object, _path, FileMode.Create, FileAccess.Read, (int)_bufferSize);
+        }
+
+        protected void Act()
+        {
+            _actual = _sftpFileStream.ReadByte();
+        }
+
+        [TestMethod]
+        public void ReadByteShouldReturnFirstByteThatWasReadFromServer()
+        {
+            Assert.AreEqual(_data[0], _actual);
+        }
+
+        [TestMethod]
+        public void PositionShouldReturnOne()
+        {
+            _sftpSessionMock.InSequence(_sequence)
+                            .Setup(p => p.IsOpen)
+                            .Returns(true);
+
+            Assert.AreEqual(1L, _sftpFileStream.Position);
+        }
+    }
+}

src/Renci.SshNet.Tests/Renci.SshNet.Tests.csproj

@@ -417,6 +417,7 @@
     <Compile Include="Classes\Sftp\Responses\SftpVersionResponseTest.cs" />
     <Compile Include="Classes\Sftp\SftpFileStreamTest_Dispose_Disposed.cs" />
     <Compile Include="Classes\Sftp\SftpFileStreamTest_Finalize_SessionOpen.cs" />
+    <Compile Include="Classes\Sftp\SftpFileStreamTest_ReadByte_ReadMode_NoDataInWriteBufferAndNoDataInReadBuffer_LessDataThanReadBufferSizeAvailable.cs" />
     <Compile Include="Classes\Sftp\SftpFileStreamTest_SetLength_Closed.cs" />
     <Compile Include="Classes\Sftp\SftpFileStreamTest_SetLength_Disposed.cs" />
     <Compile Include="Classes\Sftp\SftpFileStreamTest_SetLength_SessionNotOpen.cs" />
@@ -424,6 +425,7 @@
     <Compile Include="Classes\Sftp\SftpFileStreamTest_SetLength_SessionOpen_FIleAccessReadWrite.cs" />
     <Compile Include="Classes\Sftp\SftpFileStreamTest_SetLength_SessionOpen_FIleAccessWrite.cs" />
     <Compile Include="Classes\Sftp\SftpFileStreamTest_Write_SessionOpen_CountGreatherThanTwoTimesTheWriteBufferSize.cs" />
+    <Compile Include="Classes\Sftp\SftpFileStreamTest_ReadByte_ReadMode_NoDataInWriteBufferAndNoDataInReadBuffer_Eof.cs" />
     <Compile Include="Classes\Sftp\SftpFileTest.cs" />
     <Compile Include="Classes\Sftp\SftpSessionTest_Connected_RequestRead.cs" />
     <Compile Include="Classes\Sftp\SftpSessionTest_Connected_RequestStatVfs.cs" />

src/Renci.SshNet/Sftp/SftpFileStream.cs

@@ -397,7 +397,6 @@ namespace Renci.SshNet.Sftp
                     var data = _session.RequestRead(_handle, (ulong)_position, (uint)_readBufferSize);
 
                     _bufferLen = data.Length;
-                    Buffer.BlockCopy(data, 0, _readBuffer, 0, _readBufferSize);
                     _serverFilePosition = (ulong)_position;
 
                     if (_bufferLen == 0)
@@ -405,6 +404,8 @@ namespace Renci.SshNet.Sftp
                         // We've reached EOF.
                         return -1;
                     }
+
+                    Buffer.BlockCopy(data, 0, _readBuffer, 0, _bufferLen);
                 }
 
                 // Extract the next byte from the buffer.