private static object CreateElement(Field field, int index, Dictionary <string, IList> columns)
{
if (field.SchemaType == SchemaType.Map)
{
return(((MapField)field).CreateCellValue(columns, index));
}
else if (field.SchemaType == SchemaType.Struct)
{
return(Extract(((StructField)field).Fields, index, columns));
}
else if (field.SchemaType == SchemaType.List)
{
ListField lf = (ListField)field;
if (lf.Item.SchemaType == SchemaType.Struct)
{
StructField structField = (StructField)lf.Item;
Dictionary <string, IList> elementColumns = CreateFieldColumns(structField.Fields, index, columns, out int count);
var rows = new List <Row>(count);
for (int i = 0; i < count; i++)
{
Row row = Extract(structField.Fields, i, elementColumns);
rows.Add(row);
}
return(rows);
}
else if (lf.Item.SchemaType == SchemaType.Data)
{
DataField dataField = (DataField)lf.Item;
IList values = GetFieldPathValues(dataField, index, columns);
return(values);
}
else
{
throw OtherExtensions.NotImplementedForPotentialAssholesAndMoaners($"reading {lf.Item.SchemaType} from lists");
}
}
else
{
if (!columns.TryGetValue(field.Path, out IList values))
{
throw new ParquetException($"something terrible happened, there is no column by name '{field.Name}' and path '{field.Path}'");
}
return(values[index]);
}
}
static void AddList(Dictionary <string, IList> columns, ListField listField, object value)
{
/*
* Value slicing can happen only when entering a list and in no other cases.
* Only list is changing hierarchy dramatically.
*/
switch (listField.Item.SchemaType)
{
case SchemaType.Struct:
StructField structField = (StructField)listField.Item;
IEnumerable <Row> rows = value as IEnumerable <Row>;
var deepColumns = new Dictionary <string, IList>();
foreach (Row row in rows)
{
Append(deepColumns, structField.Fields, row);
}
SliceIn(columns, deepColumns);
break;
case SchemaType.Data:
DataField dataField = (DataField)listField.Item;
IDataTypeHandler handler = DataTypeFactory.Match(dataField);
IList values = handler.CreateEmptyList(dataField.HasNulls, dataField.IsArray, 0);
foreach (object v in (IEnumerable)value)
{
values.Add(v);
}
GetValues(columns, dataField, true, true).Add(values);
break;
default:
throw OtherExtensions.NotImplementedForPotentialAssholesAndMoaners($"adding {listField.Item.SchemaType} to list");
}
}