private int EnsureCharBuffer(int requestedLength)
{
Monitor.Enter(_syncRoot);
try
{
if (_lineIndex < -1)
{
throw new ObjectDisposedException(GetType().AssemblyQualifiedName);
}
if (_lineIndex < 0)
{
throw new InvalidOperationException("Stream reader has already been closed.");
}
int availableSpace;
int bytesInRequestedChars = _encoding.GetMaxByteCount(requestedLength);
if (requestedLength <= _charBuffer.Count || _charBuffer.Free == 0 || (availableSpace = EnsureRawBuffer(bytesInRequestedChars)) == 0)
{
return(_charBuffer.Count);
}
requestedLength = _charBuffer.Free;
char[] convertedChars;
try { convertedChars = _encoding.GetChars(_rawBuffer.Peek(bytesInRequestedChars)); }
catch { convertedChars = _encoding.GetChars(_rawBuffer.Peek(bytesInRequestedChars - 1)); }
int charAddCount = _charBuffer.Write(convertedChars);
if (charAddCount < requestedLength)
{
convertedChars = convertedChars.Take(charAddCount).ToArray();
}
_rawBuffer.Purge(_encoding.GetByteCount(convertedChars));
return(_charBuffer.Count);
}
finally { Monitor.Exit(_syncRoot); }
}
public override int Peek()
{
Monitor.Enter(_syncRoot);
try
{
if (_lineIndex < -1)
{
throw new ObjectDisposedException(GetType().AssemblyQualifiedName);
}
if (_lineIndex < 0)
{
throw new InvalidOperationException("Stream reader has already been closed.");
}
EnsureCharBuffer(1);
return(_charBuffer.Peek(1).Cast <int>().DefaultIfEmpty(-1).First());
}
finally { Monitor.Exit(_syncRoot); }
}
public RewindableStreamReader(Stream stream, Encoding encoding, bool detectEncodingFromByteOrderMarks, int bufferSize, bool leaveOpen,
bool omitCrFromNewLine)
{
if (stream == null)
{
throw new ArgumentNullException("stream");
}
if (!stream.CanRead)
{
throw new ArgumentException("The stream does not support reading.", "stream");
}
if (!stream.CanSeek)
{
throw new ArgumentException("The stream does not support seeking.", "stream");
}
if (bufferSize < 1)
{
throw new ArgumentOutOfRangeException("bufferSize", "Buffer size must be greater than zero.");
}
_leaveOpen = leaveOpen;
_rawBuffer = new ValueBuffer <byte>(bufferSize);
_charBuffer = new ValueBuffer <char>(bufferSize);
if (detectEncodingFromByteOrderMarks)
{
int readLen;
try
{
ReadOnlyCollection <Tuple <Encoding, byte[]> > detectableEncodings = DetectableEncodings;
readLen = DetectableEncodings[0].Item2.Length;
EnsureRawBuffer(readLen);
}
catch (ObjectDisposedException exception)
{
throw new InvalidOperationException("Stream has already been disposed", exception);
}
if (_rawBuffer.Count >= DetectableEncodings[DetectableEncodings.Count - 1].Item2.Length)
{
byte[] bom = _rawBuffer.Peek(readLen);
Encoding e = (bom.Length > 0) ? DetectEncodingFromBytes(bom, 0, bom.Length) : null;
if (e != null)
{
bom = e.GetPreamble();
if (bom.Length > 0 && _rawBuffer.StartsWith(bom))
{
_rawBuffer.Purge(bom.Length);
}
encoding = e;
}
}
}
if (encoding == null)
{
encoding = DefaultEncoding;
}
_encoding = encoding.Clone() as Encoding;
_encoding.DecoderFallback = new DecoderExceptionFallback();
_encoding.EncoderFallback = new EncoderExceptionFallback();
_maxSingleCharByteCount = (_encoding.IsSingleByte) ? 1 : _encoding.GetMaxByteCount(1);
_omitCrFromNewLine = omitCrFromNewLine;
_newLineCharSequence = (omitCrFromNewLine) ? new char[] { '\n' } : new char[] { '\r', '\n' };
_newLineByteSequence = _encoding.GetBytes(_newLineCharSequence);
_innerStream = stream;
}
