// Extract a file from our archive
public void ExtractFile(TARMetaData entry, string output)
{
// Check we're extracting a normal file
if (entry.GetTypeFlags() == TARMetaData.TypeFlags.NormalFile)
{
//Create any directories as required
string directory = Path.GetDirectoryName(output);
if (!string.IsNullOrEmpty(directory) && !Directory.Exists(directory))
{
Directory.CreateDirectory(directory);
}
{
// Open relevant streams and extract
using (var stream = File.OpenRead(Filename))
if (isCompressed)
{
using (var gzip = new GZipStream(stream, CompressionMode.Decompress))
ExtractFile(entry, gzip, output);
}
else
{
ExtractFile(entry, stream, output);
}
}
}
}
// Add a file to our archive using streams
// For simplicity, we always add to the start of the archive
private void AddFile(string filePath, Stream streamIn, Stream streamOut)
{
// For the user name and user group, we use Environment.UserName
// I haven't found a simple, platform independent way of getting the
// User Group correctly
string userName = Environment.UserName;
string userGroup = Environment.UserName;
// Read all the file data to add
byte[] fileData = File.ReadAllBytes(filePath);
// Use the File's Last Write time as the file's time in the archive
long currentTime = new DateTimeOffset(File.GetLastWriteTime(filePath)).ToUnixTimeSeconds();
// Create the metadata structure
TARMetaData fileMD = TARMetaData.CreateDefaultFileMetaData(Path.GetFileName(filePath), fileData.Length, currentTime, userName, userGroup);
// Copy the metadata to a byte array and write it
byte[] bAssetMD = fileMD.ToByteArray(true);
streamOut.Write(bAssetMD, 0, bAssetMD.Length);
// Then write out the file following this
streamOut.Write(fileData, 0, fileData.Length);
// Pad after the file data until we reach a 512 byte boundary if needed
if (fileData.Length % 512 > 0)
{
int paddingBytes = 512 - (fileData.Length % 512);
byte[] bPaddingBytes = new byte[paddingBytes];
streamOut.Write(bPaddingBytes, 0, paddingBytes);
}
// Then loop through each of the original entries
foreach (TARMetaData entry in Entries)
{
//Read the original meta data from the input and write to output
var metadata = new byte[512];
streamIn.Read(metadata, 0, metadata.Length);
streamOut.Write(metadata, 0, metadata.Length);
//Read the original file data from the input and write to output
var file = new byte[entry.fileSize];
streamIn.Read(file, 0, file.Length);
streamOut.Write(file, 0, file.Length);
// Pad after the file data until we reach a 512 byte boundary if needed
if (file.Length % 512 > 0)
{
int paddingBytes = 512 - (file.Length % 512);
byte[] bPaddingBytes = new byte[paddingBytes];
streamIn.Read(bPaddingBytes, 0, paddingBytes);
streamOut.Write(bPaddingBytes, 0, paddingBytes);
}
}
}
// Remove a file from our archive using the entry name
// We cannot do in place overwrites, as we read in the original file
// And then write it out
public void RemoveFile(string entryName, string output, bool outputCompressed)
{
// Look up the entry based on filename
TARMetaData entry = Entries.Find(e => e.fileName == entryName);
//If we found one, extract it
if (entry != null)
{
RemoveFile(entry, output, outputCompressed);
}
}
// Extract a file from our archive using the entry name
public void ExtractFile(string entryName, string output)
{
// Look up the entry based on filename
TARMetaData entry = Entries.Find(e => e.fileName == entryName);
//If we found one, extract it
if (entry != null)
{
ExtractFile(entry, output);
}
}
// Extract a file from a stream
private void ExtractFile(TARMetaData entry, Stream stream, string output)
{
// Open the output
using (var str = File.Open(output, FileMode.OpenOrCreate, FileAccess.Write))
{
// Create a buffer to hold the file
var buf = new byte[entry.fileSize];
// Seek to the relevant place in the stream
StreamSeek(stream, entry.FileBufferPositionStart);
// Read from the stream, write to the file
stream.Read(buf, 0, buf.Length);
str.Write(buf, 0, buf.Length);
}
}
// Remove a file from our archive
// We cannot do in place overwrites, as we read in the original file
// And then write it out
public void RemoveFile(TARMetaData entryToRemove, string output, bool outputCompressed)
{
//Create any directories as required
string directory = Path.GetDirectoryName(output);
if (!string.IsNullOrEmpty(directory) && !Directory.Exists(directory))
{
Directory.CreateDirectory(directory);
}
{
// Open relevant streams and add file as necessary
// Code is a bit messy, but essentially we have four conditions
// where the input stream can be compressed or not, and the output
// stream can be compressed or not
using (var streamIn = File.OpenRead(Filename))
{
using (var streamOut = File.Open(output, FileMode.OpenOrCreate, FileAccess.Write))
{
if (isCompressed)
{
using (var gzipIn = new GZipStream(streamIn, CompressionMode.Decompress))
{
if (outputCompressed)
{
using (var gzipOut = new GZipStream(streamOut, CompressionMode.Compress))
RemoveFile(entryToRemove, gzipIn, gzipOut);
}
else
{
RemoveFile(entryToRemove, gzipIn, streamOut);
}
}
}
else
{
if (outputCompressed)
{
using (var gzipOut = new GZipStream(streamOut, CompressionMode.Compress))
RemoveFile(entryToRemove, streamIn, gzipOut);
}
else
{
RemoveFile(entryToRemove, streamIn, streamOut);
}
}
}
}
}
}
// Load a TAR archive from a Stream
private void LoadFromStream(Stream stream)
{
// TAR Entry MetaData is stored in 512 byte buffers
var metaDataBuffer = new byte[512];
int readCount = 0;
long bufferPosition = 0;
do
{
// Read 512 bytes
readCount = stream.Read(metaDataBuffer, 0, 512);
// If we were successful
if (readCount >= 512)
{
// Unpack the MetaData and update the buffer positions
TARMetaData fileMetaData = new TARMetaData(metaDataBuffer);
fileMetaData.MetaDataBufferPositionStart = bufferPosition;
bufferPosition += readCount;
fileMetaData.FileBufferPositionStart = bufferPosition;
// If the entry has file data following it
if (fileMetaData.GetTypeFlags() == TARMetaData.TypeFlags.NormalFile ||
fileMetaData.GetTypeFlags() == TARMetaData.TypeFlags.ExtendedHeaderWithMetaDataForNextFileInArchive)
{
// Seek past the data
StreamSeek(stream, fileMetaData.fileSize);
bufferPosition += fileMetaData.fileSize;
// Make sure we seek past by a multiple of 512
if (fileMetaData.fileSize % 512 > 0)
{
long offset = 512 - (fileMetaData.fileSize % 512);
StreamSeek(stream, offset);
bufferPosition += offset;
}
}
// Store the meta data
Entries.Add(fileMetaData);
}
//Loop until we've run out of entries
} while (readCount >= 512);
}
// Remove a file from our archive
private void RemoveFile(TARMetaData entryToRemove, Stream inputStream, Stream outputStream)
{
// Loop through every entry
foreach (TARMetaData entry in Entries)
{
// Check to see if this is the entry we are removing
// If not, set write to true, else set to fale
bool write = (entry.fileName != entryToRemove.fileName);
// Read the metadata from the input file
var metadata = new byte[512];
inputStream.Read(metadata, 0, metadata.Length);
//If this file is not being deleted, write out the metadata
if (write)
{
outputStream.Write(metadata, 0, metadata.Length);
}
// Read the file data from the input file
var file = new byte[entry.fileSize];
inputStream.Read(file, 0, file.Length);
//If this file is not being deleted, write out the file
if (write)
{
outputStream.Write(file, 0, file.Length);
}
// Pad after the file data until we reach a 512 byte boundary if needed
if (file.Length % 512 > 0)
{
int paddingBytes = 512 - (file.Length % 512);
byte[] bPaddingBytes = new byte[paddingBytes];
inputStream.Read(bPaddingBytes, 0, paddingBytes);
// We only need to pad the output if the file is not being deleted
if (write)
{
outputStream.Write(bPaddingBytes, 0, paddingBytes);
}
}
}
}
