/// <summary>
/// Copy the contents of a stored file into an opened stream
/// </summary>
/// <param name="entry">Entry information of file to extract</param>
/// <param name="_stream">Stream to store the uncompressed data</param>
/// <returns>True if success, false if not.</returns>
/// <remarks>Unique compression methods are Store and Deflate</remarks>
public bool ExtractFile(ZipEntry entry, Stream stream)
{
if (!stream.CanWrite)
{
throw new InvalidOperationException("Stream cannot be written");
}
// check signature
byte[] signature = new byte[4];
this.zipFileStream.Seek(entry.HeaderOffset, SeekOrigin.Begin);
this.zipFileStream.Read(signature, 0, 4);
if (BitConverter.ToUInt32(signature, 0) != 0x04034b50)
{
return(false);
}
// Prepare streams
stream.SetLength(entry.FileSize);
var outStream = new CrcStream(stream);
this.zipFileStream.Seek(entry.FileOffset, SeekOrigin.Begin);
// Select input stream for inflating or just reading
Stream inStream = new SegmentStream(this.zipFileStream, entry.CompressedSize);
if (entry.Method == Compression.Deflate)
{
using (var intPutStream = new Ionic.Zlib.DeflateStream(inStream, Ionic.Zlib.CompressionMode.Decompress))
{
intPutStream.FlushMode = FlushType.Full;
int buffSize = 4096;
byte[] buff = new byte[buffSize];
int size = 0;
do
{
size = intPutStream.Read(buff, 0, buffSize);
if (size > 0)
{
outStream.Write(buff, 0, size);
}
} while (size > 0);
}
//inStream = new DeflateStream(inStream, CompressionMode.Decompress, true);
}
// Decompress
if (entry.Method == Compression.LZMA)
{
var decoder = new SevenZip.Compression.LZMA.Decoder();
const int PropsLength = 5;
var buffer = new byte[PropsLength];
inStream.Read(buffer, 0, sizeof(int));
if (BitConverter.ToInt32(buffer, 0) != 0x00051409)
{
throw new Exception("Invalid LZMA stream signature");
}
if (inStream.Read(buffer, 0, PropsLength) != PropsLength)
{
throw new Exception("Invalid LZMA properties length");
}
decoder.SetDecoderProperties(buffer);
decoder.Code(inStream, outStream, entry.CompressedSize, entry.FileSize, null);
}
else
{
inStream.CopyTo(outStream);
}
stream.Flush();
//if (entry.Method == Compression.Deflate)
inStream.Dispose();
if (entry.Crc32 != outStream.WriteCrc)
{
throw new Exception("Uncompressed file CRC mismatch");
}
return(true);
}