public IEnumerable <MergingCollectionEntry> Forward(int startPos, int endPosition)
{
Lock();
try
{
int totalCount = 0;
var queueComparer = new QueueEntriesComparer(reverse: false);
var queue = new VCSKicksCollection.PriorityQueue <QueueEntry>(queueComparer);
try
{
int collectionsCount = 0;
foreach (IMessagesCollection l in GetCollectionsToMerge())
{
++collectionsCount;
int localCount = l.Count;
totalCount += localCount;
IEnumerator <IndexedMessage> i = l.Forward(0, localCount).GetEnumerator();
if (i.MoveNext())
{
queue.Enqueue(new QueueEntry(i, l));
}
}
startPos = RangeUtils.PutInRange(0, totalCount, startPos);
endPosition = RangeUtils.PutInRange(0, totalCount, endPosition);
if (collectionsCount == 1) // optimized version for the case when there is only one collection to merge
{
var entry = queue.Dequeue();
using (IEnumerator <IndexedMessage> i = entry.enumerator)
{
for (int idx = 0; idx < endPosition; ++idx)
{
if (idx >= startPos)
{
yield return(new MergingCollectionEntry(
new IndexedMessage(idx, i.Current.Message), entry.collection, i.Current.Index));
}
if (!i.MoveNext())
{
break;
}
}
}
}
else
{
for (int idx = 0; idx < endPosition; ++idx)
{
var entry = queue.Dequeue();
var i = entry.enumerator;
try
{
if (idx >= startPos)
{
yield return(new MergingCollectionEntry(
new IndexedMessage(idx, i.Current.Message), entry.collection, i.Current.Index));
}
if (i.MoveNext())
{
queue.Enqueue(entry);
i = null;
}
}
finally
{
if (i != null)
{
i.Dispose();
}
}
}
}
}
finally
{
while (queue.Count != 0)
{
queue.Dequeue().enumerator.Dispose();
}
}
}
finally
{
Unlock();
}
}
public IEnumerable <MergingCollectionEntry> Reverse(int startPos, int endPosition)
{
Lock();
try
{
var queueComparer = new QueueEntriesComparer(reverse: true);
var queue = new VCSKicksCollection.PriorityQueue <QueueEntry>(queueComparer);
try
{
int collectionsCount = 0;
int c = 0;
foreach (IMessagesCollection l in GetCollectionsToMerge())
{
++collectionsCount;
int lc = l.Count;
c += lc;
IEnumerator <IndexedMessage> i = l.Reverse(lc - 1, -1).GetEnumerator();
if (i.MoveNext())
{
queue.Enqueue(new QueueEntry(i, l));
}
}
startPos = RangeUtils.PutInRange(-1, c - 1, startPos);
endPosition = RangeUtils.PutInRange(-1, c - 1, endPosition);
for (int idx = c - 1; idx > endPosition; --idx)
{
var entry = queue.Dequeue();
var i = entry.enumerator;
try
{
if (idx <= startPos)
{
yield return(new MergingCollectionEntry(
new IndexedMessage(idx, i.Current.Message), entry.collection, i.Current.Index));
}
if (i.MoveNext())
{
queue.Enqueue(entry);
i = null;
}
}
finally
{
if (i != null)
{
i.Dispose();
}
}
}
}
finally
{
while (queue.Count != 0)
{
queue.Dequeue().enumerator.Dispose();
}
}
}
finally
{
Unlock();
}
}
