private bool TryBuildNextCell(Field f, Dictionary <string, LazyColumnEnumerator> pathToColumn, out object cell)
{
switch (f.SchemaType)
{
case SchemaType.Data:
LazyColumnEnumerator dce = pathToColumn[f.Path];
//MoveNext returns either an element or a list-like structure for columns that are repeated
if (!dce.MoveNext())
{
cell = null;
return(false);
}
cell = dce.Current;
break;
case SchemaType.Map:
bool mcok = TryBuildMapCell((MapField)f, pathToColumn, out IReadOnlyList <Row> mapRow);
cell = mapRow;
return(mcok);
case SchemaType.Struct:
bool scok = TryBuildStructCell((StructField)f, pathToColumn, out Row scRow);
cell = scRow;
return(scok);
case SchemaType.List:
return(TryBuildListCell((ListField)f, pathToColumn, out cell));
default:
throw OtherExtensions.NotImplemented(f.SchemaType.ToString());
}
return(true);
}
private bool TryBuildMapCell(MapField mf, Dictionary <string, LazyColumnEnumerator> pathToColumn, out IReadOnlyList <Row> rows)
{
//"cut into" the keys and values collection
LazyColumnEnumerator keysCollection = pathToColumn[mf.Key.Path];
LazyColumnEnumerator valuesCollection = pathToColumn[mf.Value.Path];
if (keysCollection.MoveNext() && valuesCollection.MoveNext())
{
var ptc = new Dictionary <string, LazyColumnEnumerator>
{
[mf.Key.Path] = (LazyColumnEnumerator)keysCollection.Current,
[mf.Value.Path] = (LazyColumnEnumerator)valuesCollection.Current
};
rows = BuildRows(new[] { mf.Key, mf.Value }, ptc);
return(true);
}
rows = null;
return(false);
}
public IReadOnlyCollection <Row> Convert()
{
var pathToColumn = new Dictionary <string, LazyColumnEnumerator>();
foreach (DataColumn column in _columns)
{
var en = new LazyColumnEnumerator(column);
en.Reset();
pathToColumn[column.Field.Path] = en;
}
var result = new List <Row>();
ColumnsToRows(_schema.Fields, pathToColumn, result, _totalRowRount);
foreach (Row row in result)
{
row.Schema = _schema.Fields.ToArray();
}
return(result);
}