private IColumnHandler[] GetHandlersByColumnIndex(IReadOnlyList <string> columnNames, out List <string> columnNamesToOutput)
{
columnNamesToOutput = new List <string>();
IColumnHandler[] handlers = new IColumnHandler[columnNames.Count];
for (int i = 0; i < columnNames.Count; ++i)
{
string columnName = columnNames[i];
IColumnHandler handler;
if (this.DropColumns.Contains(columnName))
{
handler = null;
}
else
{
columnNamesToOutput.Add(columnName);
if (!this.HandlersByColumn.TryGetValue(columnName, out handler))
{
handler = new KeepColumnHandler();
}
}
handlers[i] = handler;
}
return(handlers);
}
/// <summary>
/// Sanitize an input file into a given output file using this Sanitizer's configuration.
/// </summary>
/// <param name="inputFile">File Path to input file</param>
/// <param name="outputFile">File Path to output file</param>
public void Sanitize(string inputFile, string outputFile)
{
using (ITabularReader reader = TabularFactory.BuildReader(inputFile))
{
// Build an array of what we'll do with each input column, and the list of columns we'll actually write
List <string> columnsToOutput;
IColumnHandler[] handlers = GetHandlersByColumnIndex(reader.Columns, out columnsToOutput);
// Find the sample column index, if any, and calculate a hash cutoff for including rows
int sampleColumnIndex = (String.IsNullOrEmpty(this.SampleColumnName) ? -1 : reader.ColumnIndex(this.SampleColumnName));
uint sampleInclusionCutoff = (uint)(uint.MaxValue * this.SampleProbability);
using (ITabularWriter writer = TabularFactory.BuildWriter(outputFile))
{
writer.SetColumns(columnsToOutput);
while (reader.NextRow())
{
// If there's a sample column, decide whether to include this row
if (sampleColumnIndex > -1)
{
// Sample *without* the hashkey, so the same rows are consistently included or excluded.
uint sampleValueHash = Hashing.Hash(reader.Current(sampleColumnIndex).ToString8(), 0);
if (sampleValueHash > sampleInclusionCutoff)
{
continue;
}
}
// Run the handler for every input column, writing the output if there is one
for (int i = 0; i < reader.CurrentRowColumns; ++i)
{
IColumnHandler handler = handlers[i];
if (handler != null)
{
String8 value = reader.Current(i).ToString8();
String8 replacement = handler.Sanitize(value);
writer.Write(replacement);
}
}
writer.NextRow();
}
}
}
}
public EchoColumnHandler(HashSet <String8> echoValues, IColumnHandler inner)
{
this.EchoValues = echoValues;
this.Inner = inner;
}