internal virtual void WriteHeader(bool reverse, int cleanLength, int dirtyLength)
{
int cleanLengthMinus2 = cleanLength - 2;
Debug.Assert(cleanLengthMinus2 >= 0);
Debug.Assert(dirtyLength >= 0);
int token = ((cleanLengthMinus2 & 0x03) << 4) | (dirtyLength & 0x07);
if (reverse)
{
token |= 1 << 7;
}
if (cleanLengthMinus2 > 0x03)
{
token |= 1 << 6;
}
if (dirtyLength > 0x07)
{
token |= 1 << 3;
}
@out.WriteByte((byte)(sbyte)token);
if (cleanLengthMinus2 > 0x03)
{
@out.WriteVInt32((int)((uint)cleanLengthMinus2 >> 2));
}
if (dirtyLength > 0x07)
{
@out.WriteVInt32((int)((uint)dirtyLength >> 3));
}
}
internal virtual void AddWord(int wordNum, byte word)
{
Debug.Assert(wordNum > lastWordNum);
Debug.Assert(word != 0);
if (!reverse)
{
if (lastWordNum == -1)
{
clean = 2 + wordNum; // special case for the 1st sequence
dirtyWords.WriteByte(word);
}
else
{
switch (wordNum - lastWordNum)
{
case 1:
if (word == 0xFF && (byte)dirtyWords.Bytes[dirtyWords.Length - 1] == 0xFF)
{
--dirtyWords.Length;
WriteSequence();
reverse = true;
clean = 2;
}
else
{
dirtyWords.WriteByte(word);
}
break;
case 2:
dirtyWords.WriteByte(0);
dirtyWords.WriteByte(word);
break;
default:
WriteSequence();
clean = wordNum - lastWordNum - 1;
dirtyWords.WriteByte(word);
break;
}
}
}
else
{
Debug.Assert(lastWordNum >= 0);
switch (wordNum - lastWordNum)
{
case 1:
if (word == 0xFF)
{
if (dirtyWords.Length == 0)
{
++clean;
}
else if ((byte)dirtyWords.Bytes[dirtyWords.Length - 1] == 0xFF)
{
--dirtyWords.Length;
WriteSequence();
clean = 2;
}
else
{
dirtyWords.WriteByte(word);
}
}
else
{
dirtyWords.WriteByte(word);
}
break;
case 2:
dirtyWords.WriteByte(0);
dirtyWords.WriteByte(word);
break;
default:
WriteSequence();
reverse = false;
clean = wordNum - lastWordNum - 1;
dirtyWords.WriteByte(word);
break;
}
}
lastWordNum = wordNum;
cardinality += BitUtil.BitCount(word);
}