private IEnumerable <LoggedBinaryReaderRegion> Merge([NotNull] IEnumerable <LoggedBinaryReaderRegion> regions)
{
using (IEnumerator <LoggedBinaryReaderRegion> e = regions.GetEnumerator())
{
if (!e.MoveNext())
{
yield break;
}
long origin = e.Current.Position;
long ending = e.Current.Position + e.Current.Length;
while (e.MoveNext())
{
LoggedBinaryReaderRegion current = e.Current;
long currentPos = current.Position;
long currentLen = current.Length;
if (currentPos > ending)
{
yield return(new LoggedBinaryReaderRegion(origin, ending - origin));
origin = currentPos;
ending = currentPos + currentLen;
}
else
{
ending = Math.Max(currentPos + currentLen, ending);
}
}
yield return(new LoggedBinaryReaderRegion(origin, ending - origin));
}
}
internal void EndGroupInternal()
{
if (Group == -1)
{
throw new InvalidOperationException($"A previous call to {nameof(BeginGroup)} has not been disposed.");
}
LoggedBinaryReaderRegion[] regions1 = Journal.Skip(Group).ToArray();
LoggedBinaryReaderRegion[] regions2 = Merge(regions1).ToArray();
if (regions2.Length > 1)
{
throw new NotSupportedException("Region grouping only supports consecutive regions.");
}
int count = Journal.Count - Group;
for (int i = 0; i < count; i++)
{
Journal.RemoveAt(Journal.Count - 1);
}
LoggedBinaryReaderRegion region = regions2.First();
Journal.Add(region);
Group = -1;
}
/// <summary>
/// Gets the regions that haven't been read.
/// </summary>
/// <returns>
/// The unread regions.
/// </returns>
public IEnumerable <LoggedBinaryReaderRegion> GetUnreadRegions()
{
IEnumerable <LoggedBinaryReaderRegion> regions = Journal.GetOrderedRegions();
using (IEnumerator <LoggedBinaryReaderRegion> e = regions.GetEnumerator())
{
// nothing at all
if (!e.MoveNext())
{
yield return(new LoggedBinaryReaderRegion(0, BaseStream.Length));
yield break;
}
LoggedBinaryReaderRegion first = e.Current;
// beginning of file
if (first.Position > 0)
{
yield return(new LoggedBinaryReaderRegion(0, first.Position));
}
// middle of file
while (e.MoveNext())
{
LoggedBinaryReaderRegion second = e.Current;
long secondPos = first.Position + first.Length;
long secondLen = second.Position - secondPos;
if (secondLen > 0)
{
yield return(new LoggedBinaryReaderRegion(secondPos, secondLen));
}
first = second;
}
// end of file
long thirdPos = first.Position + first.Length;
long thirdLen = BaseStream.Length - thirdPos;
if (thirdPos < BaseStream.Length)
{
yield return(new LoggedBinaryReaderRegion(thirdPos, thirdLen));
}
}
}