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);
}
//construct an instance of the class and parse list of zip entries
public TinyUnzip(Stream stream, bool needDispose = true)
{
if (!stream.CanSeek)
{
throw new Exception("Unzip - stream should be able to perform Seek operation!");
}
m_needDispose = needDispose;
m_stream = stream;
m_eocd = EOCD.ReadEOCD(m_stream);
m_stream.Seek(m_eocd.offsetToCentralDir, SeekOrigin.Begin);
m_reader = new BinaryReader(m_stream);
m_centralDirEntries = new CentralDirectory[m_eocd.centralDirsTotalNum];
m_entries = new List <Entry>(m_eocd.centralDirsTotalNum);
for (int i = 0; i < m_centralDirEntries.Length; i++)
{
m_centralDirEntries[i] = CentralDirectory.Read(m_reader);
Entry entry = new Entry(m_centralDirEntries[i].fileName,
m_centralDirEntries[i].comment,
m_centralDirEntries[i].compressedSize,
m_centralDirEntries[i].uncompressedSize,
m_centralDirEntries[i].fileLastModificationTime,
m_centralDirEntries[i].fileLastModificationDate,
m_centralDirEntries[i].crc32);
m_entries.Add(entry);
}
}
public static CentralDirectory Read(BinaryReader reader)
{
CentralDirectory dir = new CentralDirectory();
dir.signature = reader.ReadUInt32();
if (dir.signature != 0x02014b50)
{
throw new Exception("Bad central directory signature");
}
dir.version = reader.ReadUInt16();
dir.extractVersion = reader.ReadUInt16();
dir.generalFlags = reader.ReadUInt16();
dir.compressionMethod = reader.ReadUInt16();
dir.fileLastModificationTime = reader.ReadUInt16();
dir.fileLastModificationDate = reader.ReadUInt16();
dir.crc32 = reader.ReadUInt32();
dir.compressedSize = reader.ReadUInt32();
dir.uncompressedSize = reader.ReadUInt32();
dir.fileNameLength = reader.ReadUInt16();
dir.extraFieldLength = reader.ReadUInt16();
dir.fileCommentLength = reader.ReadUInt16();
dir.diskNumber = reader.ReadUInt16();
dir.internalFileAttributes = reader.ReadUInt16();
dir.externalFileAttributes = reader.ReadUInt32();
dir.relativeFileHeaderOffset = reader.ReadUInt32();
dir.fileName = ReadAsString(reader, dir.fileNameLength);
dir.extraField = reader.ReadBytes(dir.extraFieldLength);
dir.comment = ReadAsString(reader, dir.fileCommentLength);
return(dir);
}
//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);
}