/// <summary>
/// Finish building the file. Don't use this builder after that!
/// </summary>
/// <returns></returns>
public LoggedFile Close()
{
var ret = new LoggedFile(info.ID, log);
info = new FileLog.LoggedFileInfo();
log = null;
return(ret);
}
/// <summary>
/// Creates new file inside the passed FileLog
/// </summary>
/// <param name="log"></param>
/// <exception cref="ArgumentNullException">log</exception>
public LoggedFileBuilder(FileLog log)
{
if (log == null)
{
throw new ArgumentNullException("log");
}
this.log = log;
info = log.CreateFile();
}
/// <summary>
/// Get file lentgh
/// </summary>
/// <param name="hint">file hint as returned from GetFileHint</param>
/// <returns>file length</returns>
public long GetFileLength(FileLog.LoggedFileInfo hint)
{
lock (streamLock)
{
var initialPos = stream.Position;
stream.Position = hint.Hint;
var ret = binReader.ReadInt64();
stream.Position = initialPos;
return(ret);
}
}
/// <summary>
/// Read file data to buffer
/// </summary>
/// <param name="hint">file hint as returned from GetFileHint</param>
/// <param name="buffer">output buffer</param>
/// <param name="start">file offset to start reading at</param>
/// <param name="length">how many data to read</param>
/// <param name="offset">start offset in the output buffer</param>
/// <exception cref="ArgumentNullException">Buffer is null</exception>
/// <exception cref="BufferNotLargeEnoughException"></exception>
/// <exception cref="IndexOutOfRangeException">Data outside the file requested.</exception>
/// <exception cref="LoggedFileCorruptedException">The logged file is somehow corrupted - eg. invalid pointers, missing data, ...</exception>
public void ReadFileDataToBuffer(FileLog.LoggedFileInfo hint, byte[] buffer, long start, int length, int offset)
{
if (buffer == null)
{
throw new ArgumentNullException("buffer");
}
if (buffer.Length - offset < length)
{
throw new BufferNotLargeEnoughException();
}
lock (streamLock)
{
var initialPos = stream.Position;
stream.Position = hint.Hint;
long size = binReader.ReadInt64();
if (size < start + length)
{
throw new IndexOutOfRangeException("Data outside the file requested.");
}
long blockOffset = start % FileLog.BlockSize;
long fbt2Offset = (start / (FileLog.BlockSize)) % (FileLog.FilesPerBlock + 1);
long fbtOffset = start / (FileLog.BlockSize * (FileLog.FilesPerBlock + 1)) + 1;
long currentFbt = stream.Position;
long currentFbt2 = -1;
var streamLength = stream.Length;
while (length > 0)
{
while (fbtOffset <= FileLog.FilesPerBlock)
{
while (fbt2Offset <= FileLog.FilesPerBlock)
{
if (currentFbt2 < 0)
{
stream.Position = currentFbt + fbtOffset * sizeof(long);
currentFbt2 = binReader.ReadInt64();
if (currentFbt2 <= 0 || currentFbt2 > streamLength - FileLog.BlockSize)
{
throw new LoggedFileCorruptedException(string.Format("Expected valid pointer to FBT2 at {0}! File hint: {1}.", stream.Position - sizeof(long), hint));
}
}
stream.Position = currentFbt2 + fbt2Offset * sizeof(long);
long dataBlock = binReader.ReadInt64();
if (dataBlock <= 0 || dataBlock > streamLength - FileLog.BlockSize)
{
throw new LoggedFileCorruptedException(string.Format("Expected valid pointer to data block at {0}! File hint: {1}.", stream.Position - sizeof(long), hint));
}
stream.Position = dataBlock + blockOffset;
int toRead = Math.Min(length, (int)(FileLog.BlockSize - blockOffset));
int read = 0;
// although all data should be available the implementation may not return them all at once
while (toRead > 0 && (read = stream.Read(buffer, offset, toRead)) != 0)
{
toRead -= read;
offset += read;
length -= read;
blockOffset += read;
}
if (toRead > 0)
{
throw new LoggedFileCorruptedException(string.Format("Expected to read {0} more bytes from data block starting at {1}. File hint: {2}.", toRead, dataBlock, hint));
}
if (length == 0)
{
stream.Position = initialPos;
return;
}
blockOffset = 0;
fbt2Offset++;
}
fbt2Offset = 0;
fbtOffset++;
currentFbt2 = -1;
}
stream.Position = currentFbt;
currentFbt = binReader.ReadInt64();
if (currentFbt <= 0 || currentFbt > streamLength - FileLog.BlockSize)
{
throw new LoggedFileCorruptedException(string.Format("Expected valid pointer to next FBT at {0}! File hint: {1}.", stream.Position - sizeof(long), hint));
}
stream.Position = currentFbt;
fbtOffset -= FileLog.FilesPerBlock;
currentFbt2 = -1;
}
}
}
