public async Task <byte[]> ParseRectangle(PipeReader reader, RfbRectangleHeader header, PixelFormat format, CancellationToken token)
{
Debug.Assert(format.BitsPerPixel == 32);
var ZRLEPipe = new Pipe();
var parser = Task.Run(() => ParsePixelData(ZRLEPipe.Reader, header, token));
// read compressed length
var result = await reader.ReadMinBytesAsync(4, token);
var length = BinaryPrimitives.ReadUInt32BigEndian(result.Buffer.ForceGetReadOnlySpan(4));
reader.AdvanceTo(result.Buffer.GetPosition(4));
long remaining = length;
if (Fresh)
{
result = await reader.ReadMinBytesAsync(2, token);
reader.AdvanceTo(result.Buffer.GetPosition(2));
remaining -= 2;
Fresh = false;
}
// handle compressed rect
while (remaining > 0)
{
result = await reader.ReadAsync();
long decompressed = 0;
foreach (var segment in result.Buffer)
{
if (remaining > segment.Length)
{
await Decompress(ZRLEPipe.Writer, segment);
decompressed += segment.Length;
remaining -= segment.Length;
}
else
{
await Decompress(ZRLEPipe.Writer, segment.Slice(0, (int)remaining));
decompressed += remaining;
remaining -= remaining;
break;
}
}
reader.AdvanceTo(result.Buffer.GetPosition(decompressed));
if (remaining > 0 && result.IsCompleted)
{
throw new VncConnectionException();
}
}
ZRLEPipe.Writer.Complete();
return(await parser);
}
public async Task <byte[]> ParseRectangle(PipeReader reader, RfbRectangleHeader header, PixelFormat format, CancellationToken token)
{
Debug.Assert(format.BitsPerPixel == 32);
var remainingPixels = header.Width * header.Height;
var buf = ArrayPool <byte> .Shared.Rent(remainingPixels * 4);
var destPos = 0;
while (remainingPixels > 0)
{
var result = await reader.ReadAsync(token);
byte[]? remainder = null;
int read = 0;
foreach (var segment in result.Buffer)
{
if (remainingPixels == 0)
{
break;
}
int s = 0;
if (remainder != null)
{
if (remainder.Length + segment.Length < 4) // segment + remainder not big enough
{
var newRemainder = new byte[remainder.Length + segment.Length];
remainder.CopyTo(newRemainder, 0);
segment.CopyTo(newRemainder.AsMemory(remainder.Length));
continue;
}
else // segment + remainder big enough
{
var completedReminder = new byte[4];
remainder.CopyTo(completedReminder, 0);
segment.Span.Slice(0, 3 - remainder.Length).CopyTo(completedReminder.AsSpan(remainder.Length));
completedReminder.CopyTo(buf, destPos);
buf[destPos + 3] = 0xff;
remainingPixels--;
read += 4;
destPos += 4;
s = 4 - remainder.Length;
remainder = null;
}
}
while (remainingPixels > 0)
{
if (s + 4 <= segment.Length) // segment big enough
{
segment.Slice(s, 3).CopyTo(buf.AsMemory(destPos));
buf[destPos + 3] = 0xff;
remainingPixels--;
read += 4;
destPos += 4;
s += 4;
}
else if (s + 4 > segment.Length) // segment not big enough
{
remainder = segment.Slice(s).ToArray();
break;
}
}
}
reader.AdvanceTo(result.Buffer.GetPosition(read));
if (remainingPixels > 0 && result.IsCompleted)
{
throw new VncConnectionException();
}
}
return(buf);
}
private async Task <byte[]> ParsePixelData(PipeReader uncompressedReader, RfbRectangleHeader header, CancellationToken token)
{
byte[] data = ArrayPool <byte> .Shared.Rent(header.Width *header.Height * 4);
Array.Clear(data, 0, data.Length);
for (var y = 0; y < header.Height; y += 64)
{
var tileHeight = Math.Min(header.Height - y, 64);
for (var x = 0; x < header.Width; x += 64)
{
var tileWidth = Math.Min(header.Width - x, 64);
var result = await uncompressedReader.ReadMinBytesAsync(1, token);
byte subencoding = result.Buffer.First.Span[0];
uncompressedReader.AdvanceTo(result.Buffer.GetPosition(1));
//Debug.WriteLine($"subencoding {subencoding}");
if (subencoding == 0) // Raw
{
await ParseRawTile(uncompressedReader, data, x, y, tileWidth, tileHeight, header.Width);
}
else if (subencoding == 1) // Solid
{
var pixel = await ParseCompressedPixel(uncompressedReader, token);
for (int ty = 0; ty < tileHeight; ty++)
{
for (int tx = 0; tx < tileWidth; tx++)
{
Buffer.BlockCopy(pixel, 0, data, (
((y + ty) * header.Width) + // y + ty rows
(x + tx) // x + tx colums
) * 4, 4); // 4 bytes per pixel
}
}
ArrayPool <byte> .Shared.Return(pixel);
}
else if (subencoding <= 16) // Packed Palette
{
await ParsePackedPaletteTile(uncompressedReader, data, x, y, tileWidth, tileHeight, header.Width, subencoding);
}
else if (17 <= subencoding && subencoding <= 127)
{
throw new InvalidDataException("Subencodings 17 to 127 are unused");
}
else if (subencoding == 128) // Plain RLE
{
await ParsePlainRLETile(uncompressedReader, data, x, y, tileWidth, tileHeight, header.Width);
}
else if (130 <= subencoding && subencoding <= 255) // Palette RLE
{
await ParsePaletteRLETile(uncompressedReader, data, x, y, tileWidth, tileHeight, header.Width, subencoding - 128);
}
else
{
throw new NotImplementedException();
}
}
}
return(data);
}
