/// <summary>
/// Gets the offset of an archive that is positioned 0 or more bytes
/// from the start of the Stream.
/// </summary>
/// <param name="stream">A stream for reading the archive.</param>
/// <returns>The offset in bytes of the archive,
/// or -1 if no archive is found in the Stream.</returns>
/// <remarks>The archive must begin on a 4-byte boundary.</remarks>
public override long FindArchiveOffset(Stream stream)
{
if (stream == null)
{
throw new ArgumentNullException("stream");
}
long offset = base.FindArchiveOffset(stream);
if (offset > 0)
{
// Some self-extract packages include the exe stub in file offset calculations.
// Check the first header directory offset to decide whether the entire
// archive needs to be offset or not.
ZipEndOfCentralDirectory eocd = this.GetEOCD(null, stream);
if (eocd != null && eocd.totalEntries > 0)
{
stream.Seek(eocd.dirOffset, SeekOrigin.Begin);
ZipFileHeader header = new ZipFileHeader();
if (header.Read(stream, true) && header.localHeaderOffset < stream.Length)
{
stream.Seek(header.localHeaderOffset, SeekOrigin.Begin);
if (header.Read(stream, false))
{
return(0);
}
}
}
}
return(offset);
}
/// <summary>
/// Reads all the file headers from the central directory in the main archive.
/// </summary>
private IList <ZipFileHeader> GetCentralDirectory(IUnpackStreamContext streamContext)
{
Stream archiveStream = null;
this.currentArchiveNumber = 0;
try
{
List <ZipFileHeader> headers = new List <ZipFileHeader>();
archiveStream = this.OpenArchive(streamContext, 0);
ZipEndOfCentralDirectory eocd = this.GetEOCD(streamContext, archiveStream);
if (eocd == null)
{
return(null);
}
else if (eocd.totalEntries == 0)
{
return(headers);
}
headers.Capacity = (int)eocd.totalEntries;
if (eocd.dirOffset > archiveStream.Length - ZipFileHeader.CFH_FIXEDSIZE)
{
streamContext.CloseArchiveReadStream(
this.currentArchiveNumber, String.Empty, archiveStream);
archiveStream = null;
}
else
{
archiveStream.Seek(eocd.dirOffset, SeekOrigin.Begin);
uint sig = new BinaryReader(archiveStream).ReadUInt32();
if (sig != ZipFileHeader.CFHSIG)
{
streamContext.CloseArchiveReadStream(
this.currentArchiveNumber, String.Empty, archiveStream);
archiveStream = null;
}
}
if (archiveStream == null)
{
this.currentArchiveNumber = (short)(eocd.dirStartDiskNumber + 1);
archiveStream = streamContext.OpenArchiveReadStream(
this.currentArchiveNumber, String.Empty, this);
if (archiveStream == null)
{
return(null);
}
}
archiveStream.Seek(eocd.dirOffset, SeekOrigin.Begin);
while (headers.Count < eocd.totalEntries)
{
ZipFileHeader header = new ZipFileHeader();
if (!header.Read(archiveStream, true))
{
throw new ZipException(
"Missing or invalid central directory file header");
}
headers.Add(header);
if (headers.Count < eocd.totalEntries &&
archiveStream.Position == archiveStream.Length)
{
streamContext.CloseArchiveReadStream(
this.currentArchiveNumber, String.Empty, archiveStream);
this.currentArchiveNumber++;
archiveStream = streamContext.OpenArchiveReadStream(
this.currentArchiveNumber, String.Empty, this);
if (archiveStream == null)
{
this.currentArchiveNumber = 0;
archiveStream = streamContext.OpenArchiveReadStream(
this.currentArchiveNumber, String.Empty, this);
}
}
}
return(headers);
}
finally
{
if (archiveStream != null)
{
streamContext.CloseArchiveReadStream(
this.currentArchiveNumber, String.Empty, archiveStream);
}
}
}
/// <summary>
/// Unpacks a single file from an archive or archive chain.
/// </summary>
private void UnpackOneFile(
IUnpackStreamContext streamContext,
ZipFileHeader header,
ref Stream archiveStream)
{
ZipFileInfo fileInfo = null;
Stream fileStream = null;
try
{
Converter <Stream, Stream> compressionStreamCreator;
if (!ZipEngine.decompressionStreamCreators.TryGetValue(
header.compressionMethod, out compressionStreamCreator))
{
// Silently skip files of an unsupported compression method.
return;
}
long compressedSize;
long uncompressedSize;
long localHeaderOffset;
int archiveNumber;
uint crc;
header.GetZip64Fields(
out compressedSize,
out uncompressedSize,
out localHeaderOffset,
out archiveNumber,
out crc);
if (this.currentArchiveNumber != archiveNumber + 1)
{
if (archiveStream != null)
{
streamContext.CloseArchiveReadStream(
this.currentArchiveNumber,
String.Empty,
archiveStream);
archiveStream = null;
this.OnProgress(ArchiveProgressType.FinishArchive);
this.currentArchiveName = null;
}
this.currentArchiveNumber = (short)(archiveNumber + 1);
this.currentArchiveBytesProcessed = 0;
this.currentArchiveTotalBytes = 0;
archiveStream = this.OpenArchive(
streamContext, this.currentArchiveNumber);
FileStream archiveFileStream = archiveStream as FileStream;
this.currentArchiveName = (archiveFileStream != null ?
Path.GetFileName(archiveFileStream.Name) : null);
this.currentArchiveTotalBytes = archiveStream.Length;
this.currentArchiveNumber--;
this.OnProgress(ArchiveProgressType.StartArchive);
this.currentArchiveNumber++;
}
archiveStream.Seek(localHeaderOffset, SeekOrigin.Begin);
ZipFileHeader localHeader = new ZipFileHeader();
if (!localHeader.Read(archiveStream, false) ||
!ZipEngine.AreFilePathsEqual(localHeader.fileName, header.fileName))
{
string msg = "Could not read file: " + header.fileName;
throw new ZipException(msg);
}
fileInfo = header.ToZipFileInfo();
fileStream = streamContext.OpenFileWriteStream(
fileInfo.FullName,
fileInfo.Length,
fileInfo.LastWriteTime);
if (fileStream != null)
{
this.currentFileName = header.fileName;
this.currentFileBytesProcessed = 0;
this.currentFileTotalBytes = fileInfo.Length;
this.currentArchiveNumber--;
this.OnProgress(ArchiveProgressType.StartFile);
this.currentArchiveNumber++;
this.UnpackFileBytes(
streamContext,
fileInfo.FullName,
fileInfo.CompressedLength,
fileInfo.Length,
header.crc32,
fileStream,
compressionStreamCreator,
ref archiveStream);
}
}
finally
{
if (fileStream != null)
{
streamContext.CloseFileWriteStream(
fileInfo.FullName,
fileStream,
fileInfo.Attributes,
fileInfo.LastWriteTime);
this.currentArchiveNumber--;
this.OnProgress(ArchiveProgressType.FinishFile);
this.currentArchiveNumber++;
}
}
}