/// <summary>
/// Finds the next file marker within the byte stream.
/// </summary>
/// <param name="marker">The buffer to read file markers to</param>
/// <param name="stream">The input stream</param>
/// <returns>The <see cref="JpegFileMarker"/></returns>
public static JpegFileMarker FindNextFileMarker(byte[] marker, DoubleBufferedStreamReader stream)
{
int value = stream.Read(marker, 0, 2);
if (value == 0)
{
return(new JpegFileMarker(JpegConstants.Markers.EOI, stream.Length - 2));
}
if (marker[0] == JpegConstants.Markers.XFF)
{
// According to Section B.1.1.2:
// "Any marker may optionally be preceded by any number of fill bytes, which are bytes assigned code 0xFF."
int m = marker[1];
while (m == JpegConstants.Markers.XFF)
{
int suffix = stream.ReadByte();
if (suffix == -1)
{
return(new JpegFileMarker(JpegConstants.Markers.EOI, stream.Length - 2));
}
m = suffix;
}
return(new JpegFileMarker((byte)m, stream.Position - 2));
}
return(new JpegFileMarker(marker[1], stream.Position - 2, true));
}
public void DoubleBufferedStreamReaderCanReadSubsequentMultipleByteCorrectly()
{
using (MemoryStream stream = this.CreateTestStream())
{
var buffer = new byte[2];
byte[] expected = stream.ToArray();
var reader = new DoubleBufferedStreamReader(this.allocator, stream);
for (int i = 0, o = 0; i < expected.Length / 2; i++, o += 2)
{
Assert.Equal(2, reader.Read(buffer, 0, 2));
Assert.Equal(expected[o], buffer[0]);
Assert.Equal(expected[o + 1], buffer[1]);
Assert.Equal(o + 2, reader.Position);
int offset = i * 2;
if (offset < DoubleBufferedStreamReader.ChunkLength)
{
Assert.Equal(stream.Position, DoubleBufferedStreamReader.ChunkLength);
}
else if (offset >= DoubleBufferedStreamReader.ChunkLength && offset < DoubleBufferedStreamReader.ChunkLength * 2)
{
// We should have advanced to the second chunk now.
Assert.Equal(stream.Position, DoubleBufferedStreamReader.ChunkLength * 2);
}
else
{
// We should have advanced to the third chunk now.
Assert.Equal(stream.Position, DoubleBufferedStreamReader.ChunkLength * 3);
}
}
}
}
public int DoubleBufferedStreamRead()
{
int r = 0;
DoubleBufferedStreamReader reader = this.reader2;
byte[] b = this.chunk2;
for (int i = 0; i < reader.Length / 2; i++)
{
r += reader.Read(b, 0, 2);
}
return(r);
}
public void DoubleBufferedStreamReaderCanReadMultipleBytesFromOrigin()
{
using (MemoryStream stream = this.CreateTestStream())
{
var buffer = new byte[2];
byte[] expected = stream.ToArray();
var reader = new DoubleBufferedStreamReader(this.allocator, stream);
Assert.Equal(2, reader.Read(buffer, 0, 2));
Assert.Equal(expected[0], buffer[0]);
Assert.Equal(expected[1], buffer[1]);
// We've read a whole chunk but increment by the buffer length in our reader.
Assert.Equal(stream.Position, DoubleBufferedStreamReader.ChunkLength);
Assert.Equal(buffer.Length, reader.Position);
}
}