private static void Push(UInt8_NE_H_OutputBitStream bitStream, bool bit, Stream destination, MemoryStream data)
{
if (bitStream.Push(bit))
{
byte[] bytes = data.ToArray();
destination.Write(bytes, 0, bytes.Length);
data.SetLength(0);
}
}
private static void EncodeInternal(Stream destination, byte[] buffer, long pos, long slidingWindow, long recLength, long size)
{
UInt8_NE_H_OutputBitStream bitStream = new UInt8_NE_H_OutputBitStream(destination);
MemoryStream data = new MemoryStream();
if (size > 0)
{
long bPointer = 1, iOffset = 0;
bitStream.Push(true);
NeutralEndian.Write1(data, buffer[pos]);
while (bPointer < size)
{
long iCount = Math.Min(recLength, size - bPointer);
long iMax = Math.Max(bPointer - slidingWindow, 0);
long k = 1;
long i = bPointer - 1;
do
{
long j = 0;
while (buffer[pos + i + j] == buffer[pos + bPointer + j])
{
if (++j >= iCount)
{
break;
}
}
if (j > k)
{
k = j;
iOffset = i;
}
} while (i-- > iMax);
iCount = k;
if (iCount == 1)
{
Push(bitStream, true, destination, data);
NeutralEndian.Write1(data, buffer[pos + bPointer]);
}
else if (iCount == 2 && bPointer - iOffset > 256)
{
Push(bitStream, true, destination, data);
NeutralEndian.Write1(data, buffer[pos + bPointer]);
--iCount;
}
else if (iCount < 6 && bPointer - iOffset <= 256)
{
Push(bitStream, false, destination, data);
Push(bitStream, false, destination, data);
Push(bitStream, (((iCount - 2) >> 1) & 1) != 0, destination, data);
Push(bitStream, ((iCount - 2) & 1) != 0, destination, data);
NeutralEndian.Write1(data, (byte)(~(bPointer - iOffset - 1)));
}
else
{
Push(bitStream, false, destination, data);
Push(bitStream, true, destination, data);
long off = bPointer - iOffset - 1;
ushort info = (ushort)(~((off << 8) | (off >> 5)) & 0xFFF8);
if (iCount < 10) // iCount - 2 < 8
{
info |= (ushort)(iCount - 2);
BigEndian.Write2(data, info);
}
else
{
BigEndian.Write2(data, info);
NeutralEndian.Write1(data, (byte)(iCount - 9));
}
}
bPointer += iCount;
}
}
Push(bitStream, false, destination, data);
Push(bitStream, true, destination, data);
NeutralEndian.Write1(data, 0);
NeutralEndian.Write1(data, 0xF0);
NeutralEndian.Write1(data, 0);
bitStream.Flush(true);
byte[] bytes = data.ToArray();
destination.Write(bytes, 0, bytes.Length);
}
