private static void AddTimeStamp(int deltaFromStart, ref BitsBuffer bitsBuffer, SegmentHeader *tempHeader)
{
if (tempHeader->NumberOfEntries == 0)
{
bitsBuffer.AddValue((ulong)deltaFromStart, BitsForFirstTimestamp);
tempHeader->PreviousDelta = DefaultDelta;
return;
}
int delta = deltaFromStart - tempHeader->PreviousTimeStamp;
int deltaOfDelta = delta - tempHeader->PreviousDelta;
if (deltaOfDelta == 0)
{
bitsBuffer.AddValue(0, 1);
return;
}
if (deltaOfDelta > 0)
{
// There are no zeros. Shift by one to fit in x number of bits
deltaOfDelta--;
}
int absValue = Math.Abs(deltaOfDelta);
foreach (var timestampEncoding in TimestampEncodingDetails.Encodings)
{
if (absValue < timestampEncoding.MaxValueForEncoding)
{
bitsBuffer.AddValue((ulong)timestampEncoding.ControlValue, timestampEncoding.ControlValueBitLength);
// Make this value between [0, 2^timestampEncodings[i].bitsForValue - 1]
long encodedValue = deltaOfDelta + timestampEncoding.MaxValueForEncoding;
bitsBuffer.AddValue((ulong)encodedValue, timestampEncoding.BitsForValue);
break;
}
}
tempHeader->PreviousTimeStamp = deltaFromStart;
tempHeader->PreviousDelta = delta;
}
private int GetNumberOfBytes(SegmentHeader *header)
{
var bitsHeader = GetBitsBuffer(Header);
return(bitsHeader.NumberOfBytes + GetDataStart(Header));
}
private void WriteTag(Span <byte> tag, ref BitsBuffer tempBitsBuffer, SegmentHeader *tempHeader, int baseNumberOfBits)
{
if (tag.Length > byte.MaxValue)
{
ThrowInvalidTagLength();
}
var actualBitsBuffer = GetBitsBuffer();
int a = 136;
var r = actualBitsBuffer.ReadValue(ref a, 11);
var tagEnum = new TagEnumerator(actualBitsBuffer /* need to read the previous values */,
tempHeader->PreviousTagPosition);
if (tagEnum.TryGetPrevious(out var prevTag, out var previousIndex))
{
if (prevTag.SequenceEqual(tag))
{
tempBitsBuffer.AddValue(0, 1); // reuse previous buffer
return;
}
// go back a maximum of 8 tags, to avoid N**2 operations
// after 8 tags, we'll just write the tag again
for (int i = 0; i < 8; i++)
{
if (tagEnum.TryGetPrevious(out prevTag, out previousIndex) == false)
{
break;
}
if (prevTag.SequenceEqual(tag))
{
tempBitsBuffer.AddValue(1, 1);
tempBitsBuffer.AddValue((ulong)previousIndex, BitsForTagLen);
if (previousIndex != 0)
{
// re-arrange the previous pointer for the previous value
// to point to the current one
actualBitsBuffer.SetBits(
(previousIndex + 1 + tag.Length) * 8,
tempHeader->PreviousTagPosition,
BitsForTagLen
);
tempHeader->PreviousTagPosition = (ushort)previousIndex;
}
return;
}
}
}
tempBitsBuffer.AddValue(1, 1);
int currentBitPosition = baseNumberOfBits + tempBitsBuffer.NumberOfBits + BitsForTagLen;
int currentTagPosition = GetByteIndex(currentBitPosition);
var bitsToSkip = ToByteAlignment(currentBitPosition);
tempBitsBuffer.AddValue((ulong)currentTagPosition, BitsForTagLen);
tempBitsBuffer.Header->BitsPosition += (ushort)bitsToSkip;
tempBitsBuffer.AddValue((ulong)tag.Length, 8);
for (int i = 0; i < tag.Length; i++)
{
tempBitsBuffer.AddValue(tag[i], 8);
}
tempBitsBuffer.AddValue(tempHeader->PreviousTagPosition, BitsForTagLen);
tempHeader->PreviousTagPosition = (ushort)(currentTagPosition);
}
