private long FindContinuationOffset(PostingListAddress address)
{
var offset = address.Offset;
var buffer = new byte[PostingListReader.ReadBufferSize];
while (true)
{
int read = persistentStorage.Read(offset, buffer, 0, buffer.Length);
if (read == 0)
{
break;
}
offset += read;
for (int i = 0; i < read; ++i)
{
if (buffer[i] == EmptyContinuationAddress[0])
{
var readNext = persistentStorage.Read(offset - read + i, buffer, 0, EmptyContinuationAddress.Length);
var nextOffsetText = System.Text.Encoding.UTF8.GetString(buffer, 4, 8);
var nextOffset = Convert.ToInt32(nextOffsetText, 16);
if (nextOffset < 0)
{
return(offset - read + i);
}
offset = nextOffset;
break;
}
}
}
return(-1);
}
public IPostingList Get(PostingListAddress address)
{
var offset = address.Offset;
var line = new StringBuilder();
var buffer = new byte[ReadBufferSize];
var done = false;
while (!done)
{
int read = persistentStorage.Read(offset, buffer, 0, buffer.Length);
if (read == 0)
{
break;
}
offset += read;
for (int i = 0; i < read; ++i)
{
if (buffer[i] == PostingListWriter.EmptyContinuationAddress[0])
{
read = persistentStorage.Read(offset - read + i, buffer, 0, PostingListWriter.EmptyContinuationAddress.Length);
var nextOffsetText = System.Text.Encoding.UTF8.GetString(buffer, 4, 8);
var nextOffset = Convert.ToInt32(nextOffsetText, 16);
if (nextOffset < 0)
{
done = true;
break;
}
line.Append(';');
offset = nextOffset;
break;
}
//if (buffer[i] == '\r' || buffer[i] == '\n')
//{
// done = true;
// break;
//}
line.Append((char)buffer[i]);
}
}
return(new PostingListArray(line.ToString().Split(';').Select(Occurrence.Parse).ToArray()));
}
private bool NextChar()
{
if (indxInBuffer + 1 >= dataInBuffer)
{
int read = persistentStorage.Read(readOffset, buffer, 0, buffer.Length);
if (read == 0)
{
isEof = true;
return(false);
}
readOffset += read;
dataInBuffer = read;
indxInBuffer = 0;
return(true);
}
indxInBuffer++;
return(true);
}
private int GetFileBufferForIndex(long index)
{
var offset = index * recordSize + headerSize;
if (!(bufferFileOffset <= offset && (offset + recordSize) <= (bufferFileOffset + bufferDataSize)))
{
FlushBuffer();
int read = persistentStorage.Read(offset, buffer, 0, buffer.Length);
Array.Clear(buffer, read, buffer.Length - read);
bufferFileOffset = offset;
bufferDataSize = buffer.Length; //TODO: Extend file size to cover buffer?
dataChanged = false;
}
checked
{
return((int)(offset - bufferFileOffset));
}
}
public int Read(long fileOffset, byte[] buffer, int offset, int count)
{
return(instance.Read(fileOffset, buffer, offset, count));
}
