private static void Decode(Stream input, Stream output, Endianness endianness)
{
using (PaddedStream paddedInput = new PaddedStream(input, 2, PaddedStreamMode.Read))
{
byte packetLength = NeutralEndian.Read1(paddedInput);
var readBitfield = GetBitfieldReader(NeutralEndian.Read1(paddedInput));
ushort incrementingValue;
ushort commonValue;
InputBitStream <ushort> bitStream;
Action <Stream, ushort> write2;
if (endianness == Endianness.BigEndian)
{
incrementingValue = BigEndian.Read2(paddedInput);
commonValue = BigEndian.Read2(paddedInput);
bitStream = new UInt16BE_E_L_InputBitStream(paddedInput);
write2 = Write2BE;
}
else
{
incrementingValue = LittleEndian.Read2(paddedInput);
commonValue = LittleEndian.Read2(paddedInput);
bitStream = new UInt16LE_E_L_InputBitStream(paddedInput);
write2 = Write2LE;
}
// Loop until the end-of-data marker is found (if it is not found before the end of the stream, UInt8InputBitStream
// will throw an exception)
for (; ;)
{
if (bitStream.Get())
{
int mode = bitStream.Read(2);
int count = bitStream.Read(4);
switch (mode)
{
case 0:
case 1:
{
ushort flags = readBitfield(bitStream);
ushort outv = (ushort)(bitStream.Read(packetLength) | flags);
do
{
write2(output, outv);
outv += (ushort)mode;
} while (--count >= 0);
}
break;
case 2:
mode = -1;
goto case 0;
case 3:
{
// End of compressed data
if (count == 0xf)
{
return;
}
do
{
ushort flags = readBitfield(bitStream);
ushort outv = bitStream.Read(packetLength);
write2(output, (ushort)(outv | flags));
} while (--count >= 0);
}
break;
}
}
else
{
bool mode = bitStream.Get();
int count = bitStream.Read(4);
if (mode)
{
do
{
write2(output, commonValue);
} while (--count >= 0);
}
else
{
do
{
write2(output, incrementingValue++);
} while (--count >= 0);
}
}
}
}
}
private static void DecodeInternal(Stream source, Stream destination, ref long decompressedBytes)
{
UInt16LE_E_L_InputBitStream bitStream = new UInt16LE_E_L_InputBitStream(source);
for (; ;)
{
if (bitStream.Pop())
{
NeutralEndian.Write1(destination, NeutralEndian.Read1(source));
++decompressedBytes;
}
else
{
long count = 0;
long offset = 0;
if (bitStream.Pop())
{
byte low = NeutralEndian.Read1(source);
byte high = NeutralEndian.Read1(source);
count = high & 0x07;
if (count == 0)
{
count = NeutralEndian.Read1(source);
if (count == 0)
{
break;
}
if (count == 1)
{
continue;
}
}
else
{
++count;
}
offset = ~0x1FFFL | ((0xF8 & high) << 5) | low;
}
else
{
byte low = Convert.ToByte(bitStream.Pop());
byte high = Convert.ToByte(bitStream.Pop());
count = (low << 1 | high) + 1;
offset = NeutralEndian.Read1(source);
offset |= ~0xFFL;
}
for (long i = 0; i <= count; i++)
{
long writePosition = destination.Position;
destination.Seek(writePosition + offset, SeekOrigin.Begin);
byte b = NeutralEndian.Read1(destination);
destination.Seek(writePosition, SeekOrigin.Begin);
NeutralEndian.Write1(destination, b);
}
decompressedBytes += count + 1;
}
}
}
