/// <summary>
/// Create a new LocalFileHeader
/// </summary>
/// <param name="fileName"></param>
/// <param name="encoding"></param>
/// <param name="compressionMethod"></param>
/// <param name="deflateOption"></param>
/// <param name="streaming">true if in streaming mode</param>
/// <returns></returns>
internal static ZipIOLocalFileHeader CreateNew(string fileName, Encoding encoding,
CompressionMethodEnum compressionMethod, DeflateOptionEnum deflateOption, bool streaming)
{
//this should be ensured by the higher levels
Debug.Assert(Enum.IsDefined(typeof(CompressionMethodEnum), compressionMethod));
Debug.Assert(Enum.IsDefined(typeof(DeflateOptionEnum), deflateOption));
byte[] asciiName = encoding.GetBytes(fileName);
if (asciiName.Length > ZipIOBlockManager.MaxFileNameSize)
{
throw new ArgumentOutOfRangeException("fileName");
}
ZipIOLocalFileHeader header = new ZipIOLocalFileHeader();
header._signature = ZipIOLocalFileHeader._signatureConstant;
header._compressionMethod = (ushort)compressionMethod;
if (streaming)
{
header._versionNeededToExtract = (UInt16)ZipIOVersionNeededToExtract.Zip64FileFormat;
}
else
{
header._versionNeededToExtract = (UInt16)ZipIOBlockManager.CalcVersionNeededToExtractFromCompression(
compressionMethod);
}
if (compressionMethod != CompressionMethodEnum.Stored)
{
Debug.Assert(deflateOption != DeflateOptionEnum.None); //this should be ensured by the higher levels
header.DeflateOption = deflateOption;
}
if (streaming)
{
// set bit 3
header.StreamingCreationFlag = true;
}
header._lastModFileDateTime = ZipIOBlockManager.ToMsDosDateTime(DateTime.Now);
header._fileNameLength = (UInt16)asciiName.Length;
header._fileName = asciiName;
header._extraField = ZipIOExtraField.CreateNew(!streaming /* creating padding if it is not in streaming creation mode */);
header._extraFieldLength = header._extraField.Size;
//populate frequently used field with user friendly data representations
header._stringFileName = fileName;
return(header);
}
// !!! ATTENTION !!!! This function is only supposed to be called by
// Block Manager.Save which has proper protection to ensure no stack overflow will happen
// as a result of Stream.Flush calls which in turn result in BlockManager.Save calls
public void UpdateReferences(bool closingFlag)
{
Invariant.Assert(!_blockManager.Streaming);
long uncompressedSize;
long compressedSize;
CheckDisposed();
if (closingFlag)
{
CloseExposedStreams();
}
else
{
FlushExposedStreams();
}
// At this point we can update Local Headers with the proper CRC Value
// We can also update other Local File Header Values (compressed/uncompressed size)
// we rely on our DirtyFlag property to properly account for all possbile modifications within streams
if (GetDirtyFlag(closingFlag))
{
// Remember the size of the header before update
long headerSizeBeforeUpdate = _localFileHeader.Size;
// now prior to possibly closing streams we need to preserve uncompressed Size
// otherwise Length function will fail to give it to us later after closing
uncompressedSize = _crcCalculatingStream.Length;
// calculate CRC prior to closing
_localFileHeader.Crc32 = _crcCalculatingStream.CalculateCrc();
// If we are closing we can do extra things , calculate CRC , close deflate stream
// it is particularly important to close the deflate stream as it might hold some extra bytes
// even after Flush()
if (closingFlag)
{
// we have got the CRC so we can close the stream
_crcCalculatingStream.Close();
// in order to get proper compressed size we have to close the deflate stream
if (_deflateStream != null)
{
_deflateStream.Close();
}
}
if (_fileItemStream.DataChanged)
{
_localFileHeader.LastModFileDateTime = ZipIOBlockManager.ToMsDosDateTime(DateTime.Now);
}
// get compressed size after possible closing Deflated stream
// as a result of some ineffeciencies in CRC calculation it might result in Seek in compressed stream
// and there fore switching mode and flushing extra compressed bytes
compressedSize = _fileItemStream.Length;
// this will properly (taking into account ZIP64 scenario) update local file header
// Offset is passed in to determine whether ZIP 64 is required for small files that
// happened to be located required 32 bit offset in the archive
_localFileHeader.UpdateZip64Structures(compressedSize, uncompressedSize, Offset);
// Add/remove padding to compensate the header size change
// NOTE: Padding needs to be updated only after updating all the header fields
// that can affect the header size
_localFileHeader.UpdatePadding(_localFileHeader.Size - headerSizeBeforeUpdate);
// We always save File Items in Non-streaming mode unless it wasn't touched
//in which case we leave them alone
_localFileHeader.StreamingCreationFlag = false;
_localFileDataDescriptor = null;
// in some cases UpdateZip64Structures call might result in creation/removal
// of extra field if such thing happened we need to move FileItemStream appropriatel
_fileItemStream.Move(checked (Offset + _localFileHeader.Size - _fileItemStream.Offset));
_dirtyFlag = true;
}
#if FALSE
// we would like to take this oppportunity and validate basic asumption
// that our GetDirtyFlag method is a reliable way to finding changes
// there is no scenario in which change will happened, affecting sizes
// and will not be registered by the GetDirtyFlag
// ???????????????????????
else
{
// we even willing to recalculate CRC just in case for verification purposes
UInt32 calculatedCRC32 = CalculateCrc32();
if (!_localFileHeader.StreamingCreationFlag)
{
Debug.Assert(_localFileHeader.Crc32 == calculatedCRC32);
Debug.Assert(_localFileHeader.CompressedSize == CompressedSize);
Debug.Assert(_localFileHeader.UncompressedSize == UncompressedSize);
}
else
{
Debug.Assert(_localFileDataDescriptor.Crc32 == calculatedCRC32);
Debug.Assert(_localFileDataDescriptor.CompressedSize == CompressedSize);
Debug.Assert(_localFileDataDescriptor.UncompressedSize == UncompressedSize);
}
///////////////////////////////////////////////////////////////////////
// we do not have an initialized value for the compressed size in this case
compressedSize = _fileItemStream.Length;
Debug.Assert(CompressedSize == compressedSize);
Debug.Assert(UncompressedSize == uncompressedSize);
}
#endif
}
