/// <summary>
/// Seeks the streams only in the forward direction.
/// This means that if the current position in any stream is invalid or past this point,
/// the stream will not seek backwards.
/// </summary>
/// <param name="key">the key to seek to</param>
private void SeekAllArchiveStreamsForward(TKey key)
{
foreach (BufferedArchiveStream <TKey, TValue> table in m_sortedArchiveStreams.Items)
{
if (table.CacheIsValid && table.CacheKey.IsLessThan(key))
{
table.SeekToKeyAndUpdateCacheValue(key);
}
}
//Resorts the entire list.
m_sortedArchiveStreams.Sort();
//Remove any duplicates
RemoveDuplicatesIfExists();
if (m_sortedArchiveStreams.Items.Length > 0)
{
m_firstTable = m_sortedArchiveStreams[0];
m_firstTableScanner = m_firstTable.Scanner;
}
else
{
m_firstTable = null;
m_firstTableScanner = null;
}
SetReadWhileUpperBoundsValue();
}
/// <summary>
/// Does a seek operation on the current stream when there is a seek filter on the reader.
/// </summary>
/// <returns>
/// True if the provided key is still valid within the next best fitting frame.
/// </returns>
private bool AdvanceSeekableFilter(bool isValid, TKey key)
{
TryAgain:
if (m_keySeekFilter != null && m_keySeekFilter.NextWindow())
{
//If the current point is a valid point.
//Check to see if the seek operation can be avoided.
//or if the next available point does not exist in this window.
if (isValid)
{
//If the current point is within this window
if (key.IsGreaterThanOrEqualTo(m_keySeekFilter.StartOfFrame) &&
key.IsLessThanOrEqualTo(m_keySeekFilter.EndOfFrame))
{
return(true);
}
//If the current point is after this window, seek to the next window.
if (key.IsGreaterThan(m_keySeekFilter.EndOfFrame))
{
goto TryAgain;
}
}
//If the current point is not valid, or is before m_startKey
//Advance the scanner to the next window.
SeekAllArchiveStreamsForward(m_keySeekFilter.StartOfFrame);
return(false);
}
Dispose();
m_firstTableScanner = null;
m_firstTable = null;
return(false);
}
/// <summary>
/// Compares two Archive Streams together for proper sorting.
/// </summary>
/// <param name="item1"></param>
/// <param name="item2"></param>
/// <returns></returns>
int CompareStreams(BufferedArchiveStream <TKey, TValue> item1, BufferedArchiveStream <TKey, TValue> item2)
{
if (!item1.CacheIsValid && !item2.CacheIsValid)
{
return(0);
}
if (!item1.CacheIsValid)
{
return(1);
}
if (!item2.CacheIsValid)
{
return(-1);
}
return(item1.CacheKey.CompareTo(item2.CacheKey));// item1.CurrentKey.CompareTo(item2.CurrentKey);
}
bool IsLessThan(BufferedArchiveStream <TKey, TValue> item1, BufferedArchiveStream <TKey, TValue> item2)
{
if (!item1.CacheIsValid && !item2.CacheIsValid)
{
return(false);
}
if (!item1.CacheIsValid)
{
return(false);
}
if (!item2.CacheIsValid)
{
return(true);
}
return(item1.CacheKey.IsLessThan(item2.CacheKey));// item1.CurrentKey.CompareTo(item2.CurrentKey);
}
//-------------------------------------------------------------
/// <summary>
/// Will verify that the stream is in the proper order and remove any duplicates that were found.
/// May be called after every single read, but better to be called
/// when a ReadWhile function returns false.
/// </summary>
void VerifyArchiveStreamSortingOrder()
{
if (EOS)
{
return;
}
m_sortedArchiveStreams[0].UpdateCachedValue();
if (m_sortedArchiveStreams.Items.Length > 1)
{
//If list is no longer in order
int compare = CompareStreams(m_sortedArchiveStreams[0], m_sortedArchiveStreams[1]);
if (compare == 0 && m_sortedArchiveStreams[0].CacheIsValid)
{
//If a duplicate entry is found, advance the position of the duplicate entry
RemoveDuplicatesFromList();
SetReadWhileUpperBoundsValue();
}
if (compare > 0)
{
m_sortedArchiveStreams.SortAssumingIncreased(0);
m_firstTable = m_sortedArchiveStreams[0];
m_firstTableScanner = m_firstTable.Scanner;
SetReadWhileUpperBoundsValue();
}
if (compare == 0 && !m_sortedArchiveStreams[0].CacheIsValid)
{
Dispose();
m_firstTable = null;
m_firstTableScanner = null;
}
}
else
{
if (!m_sortedArchiveStreams[0].CacheIsValid)
{
Dispose();
m_firstTable = null;
m_firstTableScanner = null;
}
}
}
/// <summary>
/// Does an unconditional seek operation to the provided key.
/// </summary>
/// <param name="key"></param>
void SeekToKey(TKey key)
{
foreach (var table in m_sortedArchiveStreams.Items)
{
table.SeekToKeyAndUpdateCacheValue(key);
}
m_sortedArchiveStreams.Sort();
//Remove any duplicates
RemoveDuplicatesIfExists();
if (m_sortedArchiveStreams.Items.Length > 0)
{
m_firstTable = m_sortedArchiveStreams[0];
m_firstTableScanner = m_firstTable.Scanner;
}
else
{
m_firstTable = null;
m_firstTableScanner = null;
}
SetReadWhileUpperBoundsValue();
}