private int ReadTimeStamp(BitsBuffer bitsBuffer)
{
if (_bitsPosisition == 0)
{
_previousTimeStamp = (int)bitsBuffer.ReadValue(ref _bitsPosisition, BitsForFirstTimestamp);
_previousTimeStampDelta = DefaultDelta;
return(_previousTimeStamp);
}
var type = bitsBuffer.FindTheFirstZeroBit(ref _bitsPosisition, TimestampEncodingDetails.MaxControlBitLength);
if (type > 0)
{
var index = type - 1;
ref var encoding = ref TimestampEncodingDetails.Encodings[index];
long decodedValue = (long)bitsBuffer.ReadValue(ref _bitsPosisition, encoding.BitsForValue);
// [0, 255] becomes [-128, 127]
decodedValue -= encoding.MaxValueForEncoding;
if (decodedValue >= 0)
{
// [-128, 127] becomes [-128, 128] without the zero in the middle
decodedValue++;
}
_previousTimeStampDelta += (int)decodedValue;
}
private void ReadValues(Span <StatefulTimeStampValue> values, ref BitsBuffer bitsBuffer)
{
for (int i = 0; i < values.Length; i++)
{
var nonZero = bitsBuffer.ReadValue(ref _bitsPosisition, 1);
if (nonZero == 0)
{
continue; // no change since last time
}
var usePreviousBlockInfo = bitsBuffer.ReadValue(ref _bitsPosisition, 1);
long xorValue;
if (usePreviousBlockInfo == 1)
{
xorValue = (long)bitsBuffer.ReadValue(ref _bitsPosisition, 64 - values[i].LeadingZeroes - values[i].TrailingZeroes);
xorValue <<= values[i].TrailingZeroes;
}
else
{
int leadingZeros = (int)bitsBuffer.ReadValue(ref _bitsPosisition, LeadingZerosLengthBits);
int blockSize = (int)bitsBuffer.ReadValue(ref _bitsPosisition, BlockSizeLengthBits) + BlockSizeAdjustment;
int trailingZeros = 64 - blockSize - leadingZeros;
xorValue = (long)bitsBuffer.ReadValue(ref _bitsPosisition, blockSize);
xorValue <<= trailingZeros;
values[i].TrailingZeroes = (byte)trailingZeros;
values[i].LeadingZeroes = (byte)leadingZeros;
}
values[i].LongValue = values[i].LongValue ^ xorValue;
}
}
public bool TryGetPrevious(out Span <byte> tag, out int previousIndex)
{
if (_previousTagPos == 0)
{
tag = default;
previousIndex = default;
return(false);
}
previousIndex = _previousTagPos;
var tagLen = _bitsBuffer.Buffer[_previousTagPos++];
tag = new Span <byte>(_bitsBuffer.Buffer + _previousTagPos, tagLen);
var offset = (_previousTagPos + tag.Length) * 8;
_previousTagPos = (int)_bitsBuffer.ReadValue(ref offset, BitsForTagLen);
return(true);
}
internal bool AddBits(BitsBuffer tempBitsBuffer)
{
if (HasAdditionalBits(tempBitsBuffer.NumberOfBits) == false)
{
return(false);
}
int read = 0;
while (read < tempBitsBuffer.NumberOfBits)
{
var toRead = Math.Min(64, tempBitsBuffer.NumberOfBits - read);
var result = tempBitsBuffer.ReadValue(ref read, toRead);
AddValue(result, toRead);
}
return(true);
}