public void Close()
{
if (_externalReader != null)
{
_externalReader.Close();
_externalReader.Dispose();
_externalReader = null;
}
}
private void FillRest <TInnerType>(long step, IExternalReader <TInnerType> reader,
IExternalWriter <TInnerType> writer, TInnerType student)
where TInnerType : class, IComparable
{
var localStep = step;
var localStudent = student;
while (localStudent != null)
{
writer.Write(localStudent);
localStep--;
localStudent = ReadNextStudentInPhase(localStep, reader, null);
}
}
///// <summary>
///// Фаза слияния, сливаем из двух источников в один документ, попутно получая сортированный фазы длинной step * 2
///// </summary>
///// <param name="readerOne">Первый источник</param>
///// <param name="readerTwo">Второй источник</param>
///// <param name="writer">получатель</param>
///// <param name="step">Длина исходной сортированной фазы</param>
private void Merge <TInnerType>(IExternalReader <TInnerType> readerOne, IExternalReader <TInnerType> readerTwo,
IExternalWriter <TInnerType> writer, long step)
where TInnerType : class, IComparable
{
while (true)
{
if (!readerOne.IsCanRead && !readerTwo.IsCanRead)
{
return;
}
DoPhase(readerOne, readerTwo, writer, step);
}
}
private TInnerType ReadNextStudentInPhase <TInnerType>(long step, IExternalReader <TInnerType> reader,
TInnerType currentStudent)
where TInnerType : class, IComparable
{
if (step <= 0)
{
return(null);
}
if (currentStudent != null)
{
return(currentStudent);
}
return(reader.IsNext() ? reader.Current : null);
}
/// <summary>
/// Фаза разделения, разделяем данный на два файла по сортированным фазам длинной step
/// </summary>
/// <param name="reader">Источник</param>
/// <param name="writerOne">Первый получатель</param>
/// <param name="writerTwo">Второй получатель</param>
/// <param name="step">Длина сортированной фазы</param>
private void Devision <TInnerType>(IExternalReader <TInnerType> reader, IExternalWriter <TInnerType> writerOne,
IExternalWriter <TInnerType> writerTwo, long step)
where TInnerType : class, IComparable
{
while (reader.IsNext())
{
writerOne.Write(reader.Current);
for (long i = 1; (i < step) && reader.IsNext(); i++)
{
writerOne.Write(reader.Current);
}
for (long i = 0; (i < step) && reader.IsNext(); i++)
{
writerTwo.Write(reader.Current);
}
}
}
private void DoPhase <TInnerType>(IExternalReader <TInnerType> readerOne, IExternalReader <TInnerType> readerTwo,
IExternalWriter <TInnerType> writer, long step)
where TInnerType : class, IComparable
{
var stepOne = step;
var stepTwo = step;
TInnerType currentFirst = null;
TInnerType currentSecond = null;
while (true)
{
currentFirst = ReadNextStudentInPhase(stepOne, readerOne, currentFirst);
currentSecond = ReadNextStudentInPhase(stepTwo, readerTwo, currentSecond);
if (currentFirst == null && currentSecond == null)
{
return;
}
if (currentFirst == null && currentSecond != null)
{
FillRest(stepTwo, readerTwo, writer, currentSecond);
return;
}
if (currentFirst != null && currentSecond == null)
{
FillRest(stepOne, readerOne, writer, currentFirst);
return;
}
if (currentFirst.CompareTo(currentSecond) > 0)
{
writer.Write(currentSecond);
stepTwo--;
currentSecond = null;
}
else
{
writer.Write(currentFirst);
stepOne--;
currentFirst = null;
}
}
}
public void Open()
{
if (_externalReader != null)
{
throw new InvalidOperationException("Reader already opened");
}
try
{
_externalReader = ReaderLocator.GetReader(_source, _behavior);
_externalReader.Open();
TotalCount = _externalReader.RecordsCount;
}
catch (Exception ex)
{
Log.Exception(ex);
Close();
_buffer.Finish();
}
}
