private void EstimatorCore <T>(RowCursor cursor, ColumnCodec col,
out Func <long> fetchWriteEstimator, out IValueWriter writer)
{
ValueGetter <T> getter = cursor.GetGetter <T>(col.SourceIndex);
IValueCodec <T> codec = col.Codec as IValueCodec <T>;
_host.AssertValue(codec);
IValueWriter <T> specificWriter = codec.OpenWriter(Stream.Null);
writer = specificWriter;
T val = default(T);
fetchWriteEstimator = () =>
{
getter(ref val);
specificWriter.Write(in val);
return(specificWriter.GetCommitLengthEstimate());
};
}
private ColumnCodec[] GetActiveColumns(Schema schema, int[] colIndices)
{
_host.AssertValue(schema);
_host.AssertValueOrNull(colIndices);
ColumnCodec[] activeSourceColumns = new ColumnCodec[Utils.Size(colIndices)];
if (Utils.Size(colIndices) == 0)
{
return(activeSourceColumns);
}
for (int c = 0; c < colIndices.Length; ++c)
{
ColumnType type = schema[colIndices[c]].Type;
IValueCodec codec;
if (!_factory.TryGetCodec(type, out codec))
{
throw _host.Except("Could not get codec for requested column {0} of type {1}", schema[c].Name, type);
}
_host.Assert(type.Equals(codec.Type));
activeSourceColumns[c] = new ColumnCodec(colIndices[c], codec);
}
return(activeSourceColumns);
}
/// <summary>
/// Returns an appropriate generic <c>WritePipe{T}</c> for the given column.
/// </summary>
public static WritePipe Create(BinarySaver parent, RowCursor cursor, ColumnCodec col)
{
Type writePipeType = typeof(WritePipe <>).MakeGenericType(col.Codec.Type.RawType);
return((WritePipe)Activator.CreateInstance(writePipeType, parent, cursor, col));
}