private (LhaContent, byte[]) ReadContent(FileStream fileStream, long?position = null)
{
if (position.HasValue)
{
_fileStreamReadyForAppend = false;
_fileStream.Seek(position.Value, SeekOrigin.Begin);
}
var streamHeaderPosition = fileStream.Position;
var readBytes = fileStream.Read(_headerBuffer, 0, 22);
if (readBytes == 0 || (readBytes > 1 && readBytes < 22))
{
_logger.Error("Abnormal end of archive file!");
//break;
return(null, null);
}
var headerLength = _headerBuffer[0];
if (headerLength == 0)
{
// End of archive
//break;
return(null, null);
}
// crc will be written later
var headerCrc = _headerBuffer[1];
//var methodId = LhaEncoding.GetString(_headerBuffer, 2, 5);
var methodId = _encodingConverter.ConvertIsoBytesToUtf8String(_headerBuffer, 2, 5);
var length000000FF = _headerBuffer[7]; // little endian
var length0000FF00 = _headerBuffer[8];
var length00FF0000 = _headerBuffer[9];
var lengthFF000000 = _headerBuffer[10];
var dateTime000000FF = _headerBuffer[15];
var dateTime0000FF00 = _headerBuffer[16];
var dateTime00FF0000 = _headerBuffer[17];
var dateTimeFF000000 = _headerBuffer[18];
var attributes = _headerBuffer[19];
var levelIdentifier = _headerBuffer[20];
var pathLength = _headerBuffer[21];
int contentLength = length000000FF;
contentLength |= length0000FF00 << 8;
contentLength |= length00FF0000 << 16;
contentLength |= lengthFF000000 << 24;
uint dateTimeInt = dateTime000000FF;
dateTimeInt |= (uint)(dateTime0000FF00 << 8);
dateTimeInt |= (uint)(dateTime00FF0000 << 16);
dateTimeInt |= (uint)(dateTimeFF000000 << 24);
var dateTime = IntToDateTime(dateTimeInt);
EnsureHeaderBufferLength(headerLength + 2);
fileStream.Read(_headerBuffer, 22, pathLength + 2);
var path = _encodingConverter.ConvertIsoBytesToUtf8String(_headerBuffer, 22, pathLength);
string comment = null;
for (var i = 0; i < pathLength; i++)
{
if (_headerBuffer[22 + i] == 0)
{
path = _encodingConverter.ConvertIsoBytesToUtf8String(_headerBuffer, 22, i);
comment = _encodingConverter.ConvertIsoBytesToUtf8String(_headerBuffer, 22 + i + 1, pathLength - i - 1);
}
}
var calcHeaderCrc = CalcHeaderCrc(2, headerLength);
if (methodId != "-lh0-")
{
throw new Exception($"Unknown Method ID in [{path}]: {methodId}");
}
if (levelIdentifier != 0)
{
throw new Exception($"Unknown Level identifier in [{path}]: {levelIdentifier}");
}
if (calcHeaderCrc != headerCrc)
{
throw new Exception($"Header CRC mismatch in [{path}]: headerCrc={headerCrc} calcHeaderCrc={calcHeaderCrc}");
}
var streamContentPosition = fileStream.Position;
fileStream.Seek(contentLength, SeekOrigin.Current);
var content = new LhaContent(path, dateTime, attributes, contentLength, streamHeaderPosition, streamContentPosition);
return(content, _headerBuffer);
}
public LhaContentFileInfo(LhaContent content, Func <Stream> getStreamAction)
{
_content = content;
_getStreamAction = getStreamAction;
}