/// <summary>
/// Gets the next set of bindings from the buffer stream.
/// </summary>
/// <returns>
/// A set of bindings.
/// </returns>
public BindingSet Next()
{
if (!HasNext)
{
throw new InvalidOperationException("No new bindings are available!");
}
//
// see if we need to look in the main-memory array, or in the secondary-memory file
if (m_posCurrent >= m_memRangeMin)
{
return(m_memBuffer[m_posCurrent++ % m_memSize]);
}
else
{
#if DEBUG
m_planOperator.StartIOWork();
#endif
//
// very important to flush the file buffer here: not everything from the writer
// might be flushed to disk, so the reader potentially does not see the full file
m_fileWriter.Flush();
m_posCurrent++;
var b = BindingSerializer.Read(m_fileReader);
#if DEBUG
m_planOperator.StopIOWork();
#endif
return(b);
}
}
/// <summary>
/// Appends a given binding set to the end of the buffer.
/// </summary>
/// <param name="value">The binding set.</param>
public void Add(BindingSet value)
{
#if DEBUG
m_planOperator.StartCPUWork();
#endif
//
// the position in the memory array where the new binding set will be inserted
var memPos = m_count % m_memSize;
if (m_memRangeMax - m_memRangeMin + 1 < m_memSize)
{
//
// if the entire buffer still fits in main memory, we can simply insert the new
// binding set and be done with it
m_memBuffer[memPos] = value;
m_memRangeMax++;
}
else
{
//
// if the buffer does not fit in memory (anymore), we need to write the tail of
// the memory array to a secondary-memory file, and insert the new binding set on
// the position of the tail
#if DEBUG
m_planOperator.StartIOWork();
#endif
if (!m_fileCreated)
{
m_fileName = String.Format("~{0}.tmp", Generator.GetRandomFilename(12));
m_fileOutStream = File.Open(m_fileName, FileMode.Create, FileAccess.Write, FileShare.Read);
m_fileInStream = File.Open(m_fileName, FileMode.Open, FileAccess.Read, FileShare.ReadWrite);
m_fileWriter = new BinaryWriter(m_fileOutStream);
m_fileReader = new BinaryReader(m_fileInStream);
m_fileCreated = true;
m_fileRangeMin = m_memRangeMin;
m_fileRangeMax = m_fileRangeMin - 1;
}
BindingSerializer.Write(m_fileWriter, m_memBuffer[memPos]);
m_memBuffer[memPos] = value;
m_memRangeMin++;
m_memRangeMax++;
m_fileRangeMax++;
#if DEBUG
m_planOperator.StopIOWork();
#endif
}
m_count++;
#if DEBUG
m_planOperator.StopCPUWork();
#endif
}
