public override void Write(byte[] buffer, int offset, int count)
{
CheckDisposed();
var done = false;
long left = count;
long current = offset;
if (_needsRead)
{
SeekInternal(_lastPosition, SeekOrigin.Begin);
NativeFile.Read(_handle, _writeBuffer, 0, (int)_blockSize);
SeekInternal(_lastPosition, SeekOrigin.Begin);
_needsRead = false;
}
while (!done)
{
_needsFlush = true;
if (_bufferedCount + left < _writeBufferSize)
{
CopyBuffer(buffer, current, left);
done = true;
current += left;
}
else
{
var toFill = _writeBufferSize - _bufferedCount;
CopyBuffer(buffer, current, toFill);
Flush();
left -= toFill;
current += toFill;
done = left == 0;
}
}
}
public static UnbufferedFileStream Create(string path,
FileMode mode,
FileAccess acc,
FileShare share,
bool sequential,
int internalWriteBufferSize,
int internalReadBufferSize,
bool writeThrough,
uint minBlockSize)
{
var blockSize = NativeFile.GetDriveSectorSize(path);
blockSize = blockSize > minBlockSize ? blockSize : minBlockSize;
if (internalWriteBufferSize % blockSize != 0)
{
throw new Exception("write buffer size must be aligned to block size of " + blockSize + " bytes");
}
if (internalReadBufferSize % blockSize != 0)
{
throw new Exception("read buffer size must be aligned to block size of " + blockSize + " bytes");
}
var handle = NativeFile.CreateUnbufferedRW(path, acc, share, mode, writeThrough);
return(new UnbufferedFileStream(handle, blockSize, internalWriteBufferSize, internalReadBufferSize));
}
public override void SetLength(long value)
{
CheckDisposed();
var aligned = GetLowestAlignment(value);
aligned = aligned == value ? aligned : aligned + _blockSize;
NativeFile.SetFileSize(_handle, aligned);
Seek(0, SeekOrigin.Begin);
}
public override int Read(byte[] buffer, int offset, int count)
{
CheckDisposed();
if (offset < 0 || buffer.Length < offset)
{
throw new ArgumentException("offset");
}
if (count < 0 || buffer.Length < count)
{
throw new ArgumentException("offset");
}
if (offset + count > buffer.Length)
{
throw new ArgumentException("offset + count must be less than size of array");
}
var position = GetLowestAlignment(Position);
var roffset = (int)(Position - position);
var bytesRead = _readBufferSize;
if (_readLocation + _readBufferSize <= position || _readLocation > position || _readLocation == 0)
{
SeekInternal(position);
bytesRead = NativeFile.Read(_handle, _readBuffer, 0, _readBufferSize);
_readLocation = position;
}
else if (_readLocation != position)
{
roffset += (int)(position - _readLocation);
}
var bytesAvailable = bytesRead - roffset;
if (bytesAvailable <= 0)
{
return(0);
}
var toCopy = count > bytesAvailable ? bytesAvailable : count;
MemCopy(_readBuffer, roffset, buffer, offset, toCopy);
_bufferedCount += toCopy;
if (count - toCopy == 0)
{
return(toCopy);
}
return(toCopy + Read(buffer, offset + toCopy, count - toCopy));
}
public override long Seek(long offset, SeekOrigin origin)
{
CheckDisposed();
if (origin == SeekOrigin.Current)
{
throw new NotImplementedException("only supports seek origin begin/end");
}
if (origin == SeekOrigin.End)
{
offset = Length + offset;
}
var aligned = GetLowestAlignment(offset);
var left = (int)(offset - aligned);
Flush();
_bufferedCount = left;
_aligned = aligned == left;
_lastPosition = aligned;
SeekInternal(aligned);
NativeFile.Read(_handle, _writeBuffer, 0, (int)_blockSize);
SeekInternal(aligned);
return(offset);
}
private void InternalWrite(byte *buffer, uint count)
{
var written = 0;
NativeFile.Write(_handle, buffer, count, ref written);
}
private void SeekInternal(long positionAligned)
{
NativeFile.Seek(_handle, positionAligned, SeekOrigin.Begin);
}
