public void ReadsExpectedBytes(int position)
{
// Arrange
var bufferA = Encoding.ASCII.GetBytes("0");
var bufferB = Encoding.ASCII.GetBytes("12");
var bufferC = Encoding.ASCII.GetBytes("345");
var bufferD = Encoding.ASCII.GetBytes("6789");
var bufferE = Encoding.ASCII.GetBytes("ABCDE");
var target = new BlockMemoryStream();
target.Append(bufferC);
target.Prepend(bufferB);
target.Append(bufferD);
target.Append(bufferE);
target.Prepend(bufferA);
var expected = "0123456789ABCDE" + new string('_', (int)target.Length);
expected = expected.Substring(position);
var buffer = Encoding.ASCII.GetBytes(new string('_', expected.Length));
target.Position = position;
// Act
var read = target.Read(buffer, 0, buffer.Length);
// Assert
var actual = Encoding.ASCII.GetString(buffer);
Assert.Equal(expected, actual);
Assert.Equal(Math.Max(0, target.Length - position), read);
}
/// <summary>
/// Initializes an instance of a buffered range reader stream.
/// </summary>
/// <param name="rangeReader">The interface used for reading ranges of bytes.</param>
/// <param name="length">The total length of the file reader by <paramref name="rangeReader"/>.</param>
/// <param name="bufferSizeProvider">The interface used to determine what buffer sizes to use.</param>
public BufferedRangeStream(IRangeReader rangeReader, long length, IBufferSizeProvider bufferSizeProvider)
: base(length)
{
_rangeReader = rangeReader;
_bufferSizeProvider = bufferSizeProvider;
_buffer = new BlockMemoryStream();
BufferPosition = length;
}