public SequenceSize SkipNext(ReadOnlySequence <byte> sequence, int maxElementsCount)
{
var result = new SequenceSize(0, 0);
if (_basePosition < _baseRowCount)
{
var baseResult = _baseReader.Skip(sequence, _baseRowCount - _basePosition, ref _baseSkipContext);
_basePosition += baseResult.Elements;
result = result.AddBytes(baseResult.Bytes);
if (_basePosition < _baseRowCount)
{
return(result);
}
}
if (!_headerSkipped)
{
if (sequence.Length - result.Bytes < sizeof(ulong))
{
return(result);
}
result = result.AddBytes(sizeof(ulong));
_headerSkipped = true;
}
var elementCount = Math.Min(((int)sequence.Length - result.Bytes) / _keySize, maxElementsCount);
result += new SequenceSize(elementCount * _keySize, elementCount);
return(result);
}
public SequenceSize Skip(ReadOnlySequence <byte> sequence, int maxElementsCount, ref object?skipContext)
{
var slice = sequence;
var result = new SequenceSize(0, 0);
LowCardinalityColumnReaderSkipContext knownSkipContext;
if (skipContext == null)
{
var header = TryReadHeader(slice);
if (header == null)
{
return(result);
}
result = result.AddBytes(header.Value.bytesRead);
slice = slice.Slice(header.Value.bytesRead);
var baseReader = _baseType.CreateColumnReader(0);
skipContext = knownSkipContext = new LowCardinalityColumnReaderSkipContext(baseReader, header.Value.keyCount, header.Value.keySize);
}
else
{
knownSkipContext = (LowCardinalityColumnReaderSkipContext)skipContext;
}
result += knownSkipContext.SkipNext(slice, maxElementsCount);
return(result);
}
public SequenceSize ReadNext(ReadOnlySequence <byte> sequence)
{
if (_position >= _rowCount)
{
throw new ClickHouseException(ClickHouseErrorCodes.DataReaderError, "Internal error. Attempt to read after the end of the column.");
}
var result = new SequenceSize(0, 0);
var slice = sequence;
if (_baseColumnReader == null)
{
var header = TryReadHeader(slice);
if (header == null)
{
return(result);
}
_baseRowCount = header.Value.keyCount;
_keySize = header.Value.keySize;
_baseColumnReader = _baseType.CreateColumnReader(_baseRowCount);
slice = slice.Slice(header.Value.bytesRead);
result = result.AddBytes(header.Value.bytesRead);
}
if (_baseRowCount > 0)
{
var baseResult = _baseColumnReader.ReadNext(slice);
_baseRowCount -= baseResult.Elements;
slice = slice.Slice(baseResult.Bytes);
result = result.AddBytes(baseResult.Bytes);
}
if (_baseRowCount > 0)
{
return(result);
}
if (_buffer == null)
{
if (slice.Length < sizeof(ulong))
{
return(result);
}
ulong length = 0;
slice.Slice(0, sizeof(ulong)).CopyTo(MemoryMarshal.AsBytes(MemoryMarshal.CreateSpan(ref length, 1)));
if ((int)length != _rowCount)
{
throw new ClickHouseException(ClickHouseErrorCodes.DataReaderError, $"Internal error. Row count check failed: {_rowCount} rows expected, {length} rows detected.");
}
_buffer = new byte[_rowCount * _keySize];
slice = slice.Slice(sizeof(ulong));
result = result.AddBytes(sizeof(ulong));
}
var elementCount = Math.Min(_rowCount - _position, (int)(slice.Length / _keySize));
var byteCount = elementCount * _keySize;
slice.Slice(0, byteCount).CopyTo(new Span <byte>(_buffer, _position * _keySize, byteCount));
_position += elementCount;
result += new SequenceSize(byteCount, elementCount);
return(result);
}
public SequenceSize ReadNext(ReadOnlySequence <byte> sequence)
{
if (_position >= _rowCount)
{
throw new ClickHouseException(ClickHouseErrorCodes.DataReaderError, "Internal error. Attempt to read after the end of the column.");
}
int bytesCount = 0;
var slice = sequence;
if (_elementColumnReader == null)
{
var totalLength = _ranges.Aggregate((ulong)0, (acc, r) => acc + (ulong)r.length);
Span <byte> sizeSpan = stackalloc byte[sizeof(ulong)];
for (int i = _ranges.Count; i < _rowCount; i++)
{
if (slice.Length < sizeSpan.Length)
{
return(new SequenceSize(bytesCount, 0));
}
ulong length;
if (slice.FirstSpan.Length >= sizeSpan.Length)
{
length = BitConverter.ToUInt64(slice.FirstSpan);
}
else
{
slice.Slice(0, sizeSpan.Length).CopyTo(sizeSpan);
length = BitConverter.ToUInt64(sizeSpan);
}
slice = slice.Slice(sizeSpan.Length);
bytesCount += sizeSpan.Length;
var offset = checked ((int)totalLength);
var rangeLength = checked ((int)(length - totalLength));
_ranges.Add((offset, rangeLength));
totalLength = length;
}
_elementColumnReader = _elementType.CreateColumnReader(checked ((int)totalLength));
if (totalLength == 0)
{
// Special case for an empty array
var result = new SequenceSize(bytesCount, _rowCount - _position);
_position = _rowCount;
return(result);
}
}
var elementsSize = _elementColumnReader.ReadNext(slice);
_elementPosition += elementsSize.Elements;
var elementsCount = 0;
while (_position < _rowCount)
{
var currentRange = _ranges[_position];
if (currentRange.length + currentRange.offset > _elementPosition)
{
break;
}
++elementsCount;
++_position;
}
return(new SequenceSize(bytesCount + elementsSize.Bytes, elementsCount));
}
public SequenceSize Add(SequenceSize size)
{
return(new SequenceSize(Bytes + size.Bytes, Elements + size.Elements));
}
public SequenceSize ReadNext(ReadOnlySequence <byte> sequence)
{
var slice = sequence;
var result = new SequenceSize(0, 0);
if (_baseReader == null)
{
var header = LowCardinalityColumnReader.TryReadHeader(slice);
if (header == null)
{
return(result);
}
result = result.AddBytes(header.Value.bytesRead);
slice = slice.Slice(header.Value.bytesRead);
_baseRowCount = header.Value.keyCount;
_keySize = header.Value.keySize;
_baseReader = _baseType.CreateSkippingColumnReader(_baseRowCount);
}
if (_basePosition < _baseRowCount)
{
var baseResult = _baseReader.ReadNext(slice);
_basePosition += baseResult.Elements;
result = result.AddBytes(baseResult.Bytes);
if (_basePosition < _baseRowCount)
{
return(result);
}
}
if (!_headerSkipped)
{
if (sequence.Length - result.Bytes < sizeof(ulong))
{
return(result);
}
ulong length = 0;
sequence.Slice(result.Bytes, sizeof(ulong)).CopyTo(MemoryMarshal.AsBytes(MemoryMarshal.CreateSpan(ref length, 1)));
if ((int)length != _rowCount)
{
throw new ClickHouseException(ClickHouseErrorCodes.DataReaderError, $"Internal error. Row count check failed: {_rowCount} rows expected, {length} rows detected.");
}
result = result.AddBytes(sizeof(ulong));
_headerSkipped = true;
}
var maxElementsCount = _rowCount - _position;
if (maxElementsCount <= 0)
{
throw new ClickHouseException(ClickHouseErrorCodes.DataReaderError, "Internal error. Attempt to read after the end of the column.");
}
var elementCount = (int)Math.Min((sequence.Length - result.Bytes) / _keySize, maxElementsCount);
_position += elementCount;
result += new SequenceSize(elementCount * _keySize, elementCount);
return(result);
}
