/// <summary>
/// Copy the contents of a stored file into an opened stream
/// </summary>
/// <param name="zfe">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(ZipFileEntry zfe, Stream stream)
{
if (!stream.CanWrite)
{
throw new InvalidOperationException("Stream cannot be written");
}
// check signature
byte[] signature = new byte[4];
this.zipFileStream.Seek(zfe.HeaderOffset, SeekOrigin.Begin);
this.zipFileStream.Read(signature, 0, 4);
if (BitConverter.ToUInt32(signature, 0) != 0x04034b50)
{
return false;
}
// Select input stream for inflating or just reading
Stream inStream;
if (zfe.Method == Compression.Store)
{
inStream = this.zipFileStream;
}
else if (zfe.Method == Compression.Deflate)
{
inStream = new DeflateStream(this.zipFileStream, CompressionMode.Decompress, true);
}
else
{
return false;
}
// Buffered copy
byte[] buffer = new byte[16384];
this.zipFileStream.Seek(zfe.FileOffset, SeekOrigin.Begin);
uint bytesPending = zfe.FileSize;
while (bytesPending > 0)
{
int bytesRead = inStream.Read(buffer, 0, (int)Math.Min(bytesPending, buffer.Length));
stream.Write(buffer, 0, bytesRead);
bytesPending -= (uint)bytesRead;
}
stream.Flush();
if (zfe.Method == Compression.Deflate)
{
inStream.Dispose();
}
return true;
}
/// <summary>
/// Read all the file records in the central directory
/// </summary>
/// <returns>List of all entries in directory</returns>
public List<ZipFileEntry> ReadCentralDir()
{
if (this.centralDirImage == null)
{
throw new InvalidOperationException("Central directory currently does not exist");
}
List<ZipFileEntry> result = new List<ZipFileEntry>();
for (int pointer = 0; pointer < this.centralDirImage.Length; )
{
uint signature = BitConverter.ToUInt32(this.centralDirImage, pointer);
if (signature != 0x02014b50)
{
break;
}
bool encodeUtf8 = (BitConverter.ToUInt16(this.centralDirImage, pointer + 8) & 0x0800) != 0;
ushort method = BitConverter.ToUInt16(this.centralDirImage, pointer + 10);
uint modifyTime = BitConverter.ToUInt32(this.centralDirImage, pointer + 12);
uint crc32 = BitConverter.ToUInt32(this.centralDirImage, pointer + 16);
uint comprSize = BitConverter.ToUInt32(this.centralDirImage, pointer + 20);
uint fileSize = BitConverter.ToUInt32(this.centralDirImage, pointer + 24);
ushort filenameSize = BitConverter.ToUInt16(this.centralDirImage, pointer + 28);
ushort extraSize = BitConverter.ToUInt16(this.centralDirImage, pointer + 30);
ushort commentSize = BitConverter.ToUInt16(this.centralDirImage, pointer + 32);
uint headerOffset = BitConverter.ToUInt32(this.centralDirImage, pointer + 42);
uint headerSize = (uint)(46 + filenameSize + extraSize + commentSize);
Encoding encoder = encodeUtf8 ? Encoding.UTF8 : DefaultEncoding;
ZipFileEntry zfe = new ZipFileEntry();
zfe.Method = (Compression)method;
zfe.FilenameInZip = encoder.GetString(this.centralDirImage, pointer + 46, filenameSize);
zfe.FileOffset = this.GetFileOffset(headerOffset);
zfe.FileSize = fileSize;
zfe.CompressedSize = comprSize;
zfe.HeaderOffset = headerOffset;
zfe.HeaderSize = headerSize;
zfe.Crc32 = crc32;
zfe.ModifyTime = DosTimeToDateTime(modifyTime);
if (commentSize > 0)
{
zfe.Comment = encoder.GetString(this.centralDirImage, pointer + 46 + filenameSize + extraSize, commentSize);
}
result.Add(zfe);
pointer += (46 + filenameSize + extraSize + commentSize);
}
return result;
}
/// <summary>
/// Copy the contents of a stored file into a physical file
/// </summary>
/// <param name="zfe">Entry information of file to extract</param>
/// <param name="filename">Name of file to store uncompressed data</param>
/// <returns>True if success, false if not.</returns>
/// <remarks>Unique compression methods are Store and Deflate</remarks>
public bool ExtractFile(ZipFileEntry zfe, string filename)
{
// Make sure the parent directory exist
string path = Path.GetDirectoryName(filename);
if (!Directory.Exists(path))
{
if (path != null)
{
Directory.CreateDirectory(path);
}
}
// Check it is directory. If so, do nothing
if (Directory.Exists(filename))
{
return true;
}
bool result = false;
using (Stream output = new FileStream(filename, FileMode.Create, FileAccess.Write))
{
result = this.ExtractFile(zfe, output);
}
File.SetCreationTime(filename, zfe.ModifyTime);
File.SetLastWriteTime(filename, zfe.ModifyTime);
return result;
}
