/// <summary>
/// Prepares object for sequential reading from the stream.
/// The object is loaded with peice of text that contains the character pointer by <paramref name="initialPosition"/>.
/// Data is loaded from the underlying stream.
/// </summary>
public void BeginReading(long initialPosition, TextAccessDirection direction)
{
if (readingStarted)
{
throw new InvalidOperationException("Cannot start reading session. Another reading session has already been started");
}
if (initialPosition < 0)
{
throw new ArgumentException("Negative positions are not allowed", "initialPosition");
}
readingStarted = true;
this.direction = direction;
this.startPosition = new TextStreamPosition(initialPosition, textStreamPositioningParams);
streamPositionToReadFromNextTime = new TextStreamPosition(initialPosition, textStreamPositioningParams).StreamPositionAlignedToBlockSize;
streamPositionAlignedToBufferSize = streamPositionToReadFromNextTime;
decoderNeedsReloading = EncodingNeedsReloading();
textBufferLength = 0;
textBufferAsString = "";
charsCutFromBeginningOfTextBuffer = 0;
charsCutFromEndOfTextBuffer = 0;
AdvanceBufferInternal(0);
}
public ITextAccessIterator OpenIterator(long initialPosition, TextAccessDirection direction)
{
if (readingStarted)
{
throw new InvalidOperationException("Another iterator already exists. Dispose it first.");
}
BeginReading(initialPosition, direction);
iterator.Open();
return(iterator);
}
void TryBeginSplittingSession(FileRange.Range range, long startPosition, MessagesParserDirection direction)
{
bool posIsOutOfRange = DetectOutOfRangeCondition(range, startPosition, direction);
if (!posIsOutOfRange)
{
TextAccessDirection accessDirection = direction == MessagesParserDirection.Forward ?
TextAccessDirection.Forward : TextAccessDirection.Backward;
textIterator = textAccess.OpenIterator(startPosition, accessDirection);
try
{
headerPointer1 = textIterator.PositionToCharIndex(startPosition);
prevHeaderPointer1 = headerPointer1;
}
catch (ArgumentOutOfRangeException)
{
posIsOutOfRange = true;
}
}
headersCounter = 0;
if (posIsOutOfRange)
{
this.range = new FileRange.Range();
SetCachedCurrentBuffer("");
currentMessageHeaderMatch = null;
ReadingSessionCleanup();
}
else
{
this.range = range;
SetCurrentDirection(direction);
UpdateCachedCurrentBuffer();
FindNextMessageStart();
}
}