public void GetUncompressedLengthExceptions()
{
var uncompressed = Encoding.ASCII.GetBytes("Hello, hello, howdy?");
var compressed = CompressTool.Compress(uncompressed);
var buffer = new byte[100];
TestException(() => { CompressTool.GetUncompressedLength(null, 0, 3); }, typeof(ArgumentNullException));
TestException(() => { CompressTool.GetUncompressedLength(compressed, -1, uncompressed.Length); }, typeof(ArgumentOutOfRangeException));
TestException(() => { CompressTool.GetUncompressedLength(compressed, 0, -1); }, typeof(ArgumentOutOfRangeException));
TestException(() => { CompressTool.GetUncompressedLength(compressed, compressed.Length - 2, 4); }, typeof(ArgumentOutOfRangeException));
TestException(() => { CompressTool.GetUncompressedLength(compressed, 0, 0); }, typeof(System.IO.IOException));
TestException(() => { CompressTool.GetUncompressedLength(compressed, compressed.Length, 0); }, typeof(System.IO.IOException));
}
/// <summary>
/// Retrieves Snappy frame from underlying stream. Retrieved frame data is stored in properties of this object.
/// Return value indicates end of stream. Exceptions indicate data integrity errors and underlying stream errors.
/// </summary>
/// <param name="stream">Underlying stream that will be read by this method.</param>
/// <returns>
/// True if frame was successfully retrieved. False if there are no more frames in the stream, i.e. the end of stream has been reached.
/// Note that reaching the end of stream in the middle of the frame is considered an error and causes exception instead.
/// </returns>
public bool Read(Stream stream)
{
try
{
var headerRead = stream.Read(WordBuffer, 0, 4);
if (headerRead == 0)
{
return(false);
}
EnsureRead(stream, WordBuffer, headerRead, 4 - headerRead);
Type = (SnappyFrameType)WordBuffer[0];
int length = WordBuffer[1] + ((int)WordBuffer[2] << 8) + ((int)WordBuffer[3] << 16);
if (Type == SnappyFrameType.Compressed || Type == SnappyFrameType.Uncompressed)
{
if (length < 4)
{
throw new InvalidDataException();
}
EnsureRead(stream, WordBuffer, 0, 4);
Checksum = (uint)WordBuffer[0] + ((uint)WordBuffer[1] << 8) + ((uint)WordBuffer[2] << 16) + ((uint)WordBuffer[3] << 24);
BufferUsage = length - 4;
if (BufferUsage > MaxBufferUsage)
{
throw new InvalidDataException();
}
EnsureBuffer(BufferUsage);
EnsureRead(stream, Buffer, 0, BufferUsage);
DataLength = Type == SnappyFrameType.Uncompressed ? BufferUsage : CompressTool.GetUncompressedLength(Buffer, 0, BufferUsage);
if (DataLength > MaxFrameSize)
{
throw new InvalidDataException();
}
}
else if (Type == SnappyFrameType.Padding || (byte)Type >= (byte)SnappyFrameType.SkippableFirst && (byte)Type <= (byte)SnappyFrameType.SkippableLast)
{
DataLength = length;
BufferUsage = 0;
Checksum = 0;
SkipBytes(stream, length);
}
else if (Type == SnappyFrameType.StreamIdentifier)
{
if (length != 6)
{
throw new InvalidOperationException();
}
DataLength = 6;
BufferUsage = 0;
Checksum = 0;
EnsureBuffer(6);
EnsureRead(stream, Buffer, 0, 6);
if (!Utils.BuffersEqual(Buffer, StreamIdentifier, 6))
{
throw new InvalidDataException();
}
}
else
{
throw new InvalidDataException();
}
return(true);
}
catch
{
SetPadding(0);
throw;
}
}
