public static LocalFileHeader Read(BinaryReader reader, CentralDirectory dirEntry)
{
reader.BaseStream.Seek(dirEntry.relativeFileHeaderOffset, SeekOrigin.Begin);
LocalFileHeader fileHeader = new LocalFileHeader();
fileHeader.signature = reader.ReadUInt32();
if (fileHeader.signature != 0x04034b50)
{
throw new Exception("Bad central directory signature");
}
fileHeader.extractVersion = reader.ReadUInt16();
fileHeader.generalFlags = reader.ReadUInt16();
fileHeader.compressionMethod = reader.ReadUInt16();
fileHeader.fileLastModificationTime = reader.ReadUInt16();
fileHeader.fileLastModificationDate = reader.ReadUInt16();
fileHeader.crc32 = reader.ReadUInt32();
fileHeader.compressedSize = reader.ReadUInt32();
fileHeader.uncompressedSize = reader.ReadUInt32();
fileHeader.fileNameLength = reader.ReadUInt16();
fileHeader.extraFieldLength = reader.ReadUInt16();
fileHeader.fileName = ReadAsString(reader, fileHeader.fileNameLength);
fileHeader.extraField = reader.ReadBytes(fileHeader.extraFieldLength);
return(fileHeader);
}
private async Task <Tuple <byte[], DateTime> > Download(PartialZipInfo info, string filePath)
{
CentralDirectoryHeader cd = info.CentralDirectory.FirstOrDefault(c => c.FileName == filePath);
DataProp dataProp;
if (cd != null)
{
dataProp = cd.GetFileInfoStruct();
byte[] localFileBuffer = await _httpService.GetRange(dataProp.headerOffset, dataProp.headerOffset + LocalFileHeader.Size - 1);
LocalFileHeader localFileHeader = new LocalFileHeader(localFileBuffer);
ulong start = dataProp.headerOffset + LocalFileHeader.Size + localFileHeader.FileNameLength + localFileHeader.ExtraFieldLength;
byte[] compressedContent = await _httpService.GetRange(start, start + dataProp.compressedSize - 1);
var dateTimeModified = ConvertDOSDateTime(dataProp.modifiedDate, dataProp.modifiedTime);
switch (localFileHeader.Compression)
{
case 0:
return(Tuple.Create(compressedContent, dateTimeModified));
case 8:
return(Tuple.Create(_deflateService.Inflate(compressedContent), dateTimeModified));
default:
throw new PartialZipUnsupportedCompressionException("Unknown compression.");
}
}
throw new PartialZipFileNotFoundException($"Could not find file in archive.");
}
private async Task <byte[]> Download(PartialZipInfo info, string filePath)
{
CentralDirectoryHeader cd = info.CentralDirectory.FirstOrDefault(c => c.FileName == filePath);
if (cd != null)
{
(ulong uncompressedSize, ulong compressedSize, ulong headerOffset, uint diskNum) = cd.GetFileInfo();
byte[] localFileBuffer = await this._httpService.GetRange(headerOffset, headerOffset + LocalFileHeader.Size - 1);
LocalFileHeader localFileHeader = new LocalFileHeader(localFileBuffer);
ulong start = headerOffset + LocalFileHeader.Size + localFileHeader.FileNameLength + localFileHeader.ExtraFieldLength;
byte[] compressedContent = await this._httpService.GetRange(start, start + compressedSize - 1);
switch (localFileHeader.Compression)
{
case 0:
return(compressedContent);
case 8:
return(this._deflateService.Inflate(compressedContent));
default:
throw new PartialZipUnsupportedCompressionException("Unknown compression.");
}
}
throw new PartialZipFileNotFoundException($"Could not find file {filePath} in archive.");
}
//gets stream for reading uncompressed data
//only one stream can be used at the same time
public Stream GetStream(string fileName)
{
CentralDirectory dir = m_centralDirEntries.Where(d => d.fileName == fileName).First();
LocalFileHeader fileHeader = LocalFileHeader.Read(m_reader, dir);
switch (fileHeader.compressionMethod)
{
//no compression
case 0:
return(new ProxyStream(m_stream, dir.compressedSize));
//deflate
case 8:
var proxy = new ProxyStream(m_stream, dir.compressedSize);
return(new DeflateStream(proxy, CompressionMode.Decompress, true));
}
throw new NotSupportedException("Compression method not supported. Method id: " + fileHeader.compressionMethod);
}
private void _read()
{
_header = new LocalFileHeader(m_io, this, m_root);
_body = m_io.ReadBytes(Header.LenBodyCompressed);
}
public LocalFileHeaderInfo(LocalFileHeader header)
: base((FileHeaderBase)header)
{
}
