/// <summary>
/// ctor: Create class from data returned by the Reader
/// </summary>
/// <param name="reader">A binary data reader for this type of data - positioned at last page</param>
public p4kEndOfCentralDirRecord(p4kRecReader reader)
{
// sanity check only
System.Diagnostics.Trace.Assert(Marshal.SizeOf(typeof(MyRecord)) == RecordLength,
"Record size does not match!(" + Marshal.SizeOf(typeof(MyRecord)).ToString( ) + ")");
if (reader.IsOpen( ))
{
try {
long cPos = p4kSignatures.FindSignatureInPage(reader, p4kSignatures.EndOfCentralDirRecord);
if (cPos >= 0)
{
m_recordOffset = cPos;
reader.Seek(cPos);
m_item = p4kRecReader.ByteToType <MyRecord>(reader.TheReader);
m_itemValid = true;
}
}
catch {
m_itemValid = false;
m_recordOffset = -1;
}
finally {
if (!m_itemValid)
{
throw new OperationCanceledException(string.Format("EOF - cannot find EndOfCentralDirRecord"));
}
}
}
}
/// <summary>
/// ctor: Create class from data returned by the Reader; starts reading at current stream position
/// </summary>
/// <param name="reader">A binary data reader for this type of data - positioned already</param>
public p4kDirectoryEntry(p4kRecReader reader)
{
// sanity check only
System.Diagnostics.Trace.Assert(Marshal.SizeOf(typeof(MyRecord)) == RecordLength,
"Record size does not match!(" + Marshal.SizeOf(typeof(MyRecord)).ToString( ) + ")");
System.Diagnostics.Trace.Assert(Marshal.SizeOf(typeof(MyZ64ExtraRecord)) == Z64ExtraRecordLength,
"Extra Record size does not match!(" + Marshal.SizeOf(typeof(MyZ64ExtraRecord)).ToString( ) + ")");
if (reader.IsOpen( ))
{
try {
// get the next Directory record
long cPos = p4kSignatures.FindSignatureInPage(reader, p4kSignatures.CentralDirRecord);
if (cPos >= 0)
{
m_recordOffset = cPos;
reader.Seek(cPos);
m_item = p4kRecReader.ByteToType <MyRecord>(reader.TheReader);
m_itemValid = true; // implicite from Find..
}
// get some file attributes
if (m_itemValid)
{
if (m_item.FilenameLength > 0)
{
ReadFilename(reader);
}
if (m_item.ExtraFieldLength > 0)
{
ReadExtradata(reader); // Likely Zip64 extensions
}
m_fileDateTime = p4kFileTStamp.FromDos(m_item.LastModDate, m_item.LastModTime); // get the file time given in the container
// check if standard fields or extension is used for size information
if (m_item.CompressedSize < 0xffffffff)
{
m_fileSizeComp = m_item.CompressedSize;
m_fileSizeUnComp = m_item.UncompressedSize;
}
else
{
m_fileSizeComp = (long)m_z64Item.CompressedSize;
m_fileSizeUnComp = (long)m_z64Item.UncompressedSize;
}
}
}
catch (Exception e) {
m_itemValid = false;
m_recordOffset = -1;
}
finally {
if (!m_itemValid)
{
throw new OperationCanceledException(string.Format("EOF - cannot find CentralDirRec in this page"));
}
}
}
}
/// <summary>
/// Read the extra data
/// </summary>
/// <param name="reader"></param>
private void ReadExtradata(p4kRecReader reader)
{
// first the Zip64 extra record
m_z64Item = p4kRecReader.ByteToType <MyZ64ExtraRecord>(reader.TheReader);
// then the rest of the extra record (is another item with tag 0x0666 and the rest lenght (ignored)
m_extraBytes = new byte[m_item.ExtraFieldLength - Z64ExtraRecordLength];
m_extraBytes = reader.ReadBytes(m_extraBytes.Length);
m_extraBytes = null; // dump it ...
// now we would be able to read the file content
}
// 4.3.6 Overall.ZIP file format:
//[local file header 1]
//[encryption header 1]
//[file data 1]
//[data descriptor 1]
// .
// .
// .
//[local file header n]
//[encryption header n]
//[file data n]
//[data descriptor n]
//[archive decryption header]
//[archive extra data record]
//[central directory header 1]
// .
// .
// .
//[central directory header n]
//[zip64 end of central directory record]
//[zip64 end of central directory locator]
//[end of central directory record]
/// <summary>
/// Retrieve the file given by the descriptor (from our list)
/// and return the content as string
/// </summary>
/// <param name="file">A file descriptor from this list</param>
/// <returns>The content of the file or an empty string</returns>
public byte[] GetFile(string p4kFilename, p4kFile file)
{
if (!File.Exists(p4kFilename))
{
return new byte[] { }
}
;
using (p4kRecReader reader = new p4kRecReader(p4kFilename)) {
return(file.GetFile(reader));
}
}
/// <summary>
/// Return the file related to this entry
/// </summary>
/// <param name="reader">An open p4k File reader</param>
/// <returns>The content of the file or an empty string</returns>
public byte[] GetFile(p4kRecReader reader)
{
if (!m_itemValid)
{
return new byte[] { }
}
; // ERROR cannot..
reader.Seek(FileHeaderOffset);
p4kFileHeader p4Kfh = new p4kFileHeader(reader);
return(p4Kfh.GetFile(reader));
}
/// <summary>
/// Returns the position of the Signature within the stream
/// Searches one page from current location starting at the end of the page
/// </summary>
/// <param name="reader">A positioned reader</param>
/// <returns>The position within the stream or -1 if not found</returns>
public static long FindSignatureInPageBackwards(p4kRecReader reader, byte[] signature)
{
long pos = reader.Position;
byte[] lPage = reader.GetPage( );
for (int i = lPage.Length - 4; i > 0; i--)
{
if (lPage.Skip(i).Take(4).SequenceEqual(signature))
{
// now this should be the start of the item [end of central directory record]
return(pos + i);
}
}
return(-1); // not found...
}
public static readonly byte[] EndOfCentralDirRecord = { 0x50, 0x4B, 0x05, 0x06 }; // (0x06054b50) 4.3.16 End of central directory record:
/// <summary>
/// Returns the position of the Signature within the stream
/// Searches one page from current location
/// </summary>
/// <param name="reader">A positioned reader</param>
/// <returns>The position within the stream or -1 if not found</returns>
public static long FindSignatureInPage(p4kRecReader reader, byte[] signature)
{
long pos = reader.Position;
byte[] lPage = reader.GetPage( );
for (int i = 0; i < lPage.Length - 4; i++)
{
if (lPage.Skip(i).Take(4).SequenceEqual(signature))
{
// now this should be the start of the item
return(pos + i);
}
}
return(-1); // not found...
}
/// <summary>
/// ctor: Create class from data returned by the Reader
/// </summary>
/// <param name="reader">A binary data reader for this type of data - positioned at last page</param>
public p4kEndOfCentralDirRecord(p4kRecReader reader)
{
// sanity check only
System.Diagnostics.Trace.Assert(Marshal.SizeOf(typeof(MyRecord)) == RecordLength,
"Record size does not match!(" + Marshal.SizeOf(typeof(MyRecord)).ToString( ) + ")");
if (reader.IsOpen( ))
{
try {
long thisPos = 0;
// 20180804BM- fix when the last page is barely used and the sig is one or more pages before
// - backup one or more pages to find end of dir (max 10 times)
int tries = 10;
while (!m_itemValid && (tries > 0))
{
thisPos = reader.Position;
long cPos = p4kSignatures.FindSignatureInPage(reader, p4kSignatures.EndOfCentralDirRecord);
if (cPos >= 0)
{
m_recordOffset = cPos;
reader.Seek(cPos);
m_item = p4kRecReader.ByteToType <MyRecord>(reader.TheReader);
m_itemValid = true;
}
else
{
// backup one page again
reader.Seek(thisPos);
reader.BackwardPage( );
tries--;
}
}
}
catch {
m_itemValid = false;
m_recordOffset = -1;
}
finally {
if (!m_itemValid)
{
throw new OperationCanceledException(string.Format("EOF - cannot find EndOfCentralDirRecord"));
}
}
}
}
/// <summary>
/// Return the file related to this entry
/// </summary>
/// <param name="reader">An open p4k File reader</param>
/// <returns>The content of the file or an empty string</returns>
public byte[] GetFile(p4kRecReader reader)
{
if (!m_itemValid)
{
return new byte[] { }
}
; // ERROR cannot..
reader.Seek(m_fileOffset);
// ?? big files may have trouble here - may be we need to read and write chunks for this
// but for now we only want to get XMLs out and that is OK with byte alloc on the heap
byte[] fileBytes = new byte[m_fileSizeComp];
fileBytes = reader.ReadBytes(fileBytes.Length);
byte[] decompFile = null;
if (m_item.CompressionMethod == 0x64)
{
// this indicates p4k ZStd compression
using (var decompressor = new Decompressor( )) {
try {
decompFile = decompressor.Unwrap(fileBytes);
return(decompFile);
}
catch (ZstdException e) {
Console.WriteLine("ZStd - Cannot decode file: " + m_filename);
Console.WriteLine("Error: " + e.Message);
//Console.ReadLine();
return(new byte[] { });
}
}
}
else
{
// plain write - might be wrong if another compression was applied..
decompFile = fileBytes;
return(decompFile);
}
}
/// <summary>
/// Scans directory entries and return the a file descriptor (string.EndsWith is used)
/// </summary>
/// <param name="p4kFilename">The p4k file</param>
/// <param name="filename">The filename to look for</param>
public p4kFile ScanDirectoryFor(string p4kFilename, string filename)
{
if (!File.Exists(p4kFilename))
{
return(null);
}
using (p4kRecReader reader = new p4kRecReader(p4kFilename)) {
// work from the end of the file
reader.GotoLastPage( );
m_endOfCentralDirRecord = new p4kEndOfCentralDirRecord(reader);
// position first
reader.Seek(m_endOfCentralDirRecord.RecordOffset - p4kRecReader.PageSize);
m_z64EndOfCentralDirLocator = new p4kZ64EndOfCentralDirLocator(reader);
// for the next the position should be found already - seek it
reader.Seek(m_z64EndOfCentralDirLocator.Z64EndOfCentralDir);
m_z64EndOfCentralDirRecord = new p4kZ64EndOfCentralDirRecord(reader);
// now we should have the start of the directory entries...
// position first
reader.Seek(m_z64EndOfCentralDirRecord.Z64StartOfCentralDir);
// loop all file - as per dir reporting
for (long i = 0; i < m_z64EndOfCentralDirRecord.NumberOfEntries; i++)
{
p4kDirectoryEntry de = new p4kDirectoryEntry(reader);
if (!string.IsNullOrEmpty(filename) && de.Filename.ToLower( ).EndsWith(filename.ToLower( )))
{
var p = new p4kFile(de); // FOUND
reader.TheReader.Close( );
return(p); // bail out if found
}
}
}
return(null);
}
/// <summary>
/// Scans directory entries and return the a list of matching file descriptors (string.Contains is used)
/// </summary>
/// <param name="p4kFilename">The p4k file</param>
/// <param name="filenamepart">The filename part to look for</param>
public IList <p4kFile> ScanDirectoryContaining(string p4kFilename, string filenamepart)
{
if (!File.Exists(p4kFilename))
{
return(null);
}
List <p4kFile> fileList = new List <p4kFile>( );
using (p4kRecReader reader = new p4kRecReader(p4kFilename)) {
// work from the end of the file
reader.GotoLastPage( );
m_endOfCentralDirRecord = new p4kEndOfCentralDirRecord(reader);
// position first
reader.Seek(m_endOfCentralDirRecord.RecordOffset - p4kRecReader.PageSize);
m_z64EndOfCentralDirLocator = new p4kZ64EndOfCentralDirLocator(reader);
// for the next the position should be found already - seek it
reader.Seek(m_z64EndOfCentralDirLocator.Z64EndOfCentralDir);
m_z64EndOfCentralDirRecord = new p4kZ64EndOfCentralDirRecord(reader);
// now we should have the start of the directory entries...
// position first
reader.Seek(m_z64EndOfCentralDirRecord.Z64StartOfCentralDir);
// loop all file - as per dir reporting
for (long i = 0; i < m_z64EndOfCentralDirRecord.NumberOfEntries; i++)
{
p4kDirectoryEntry de = new p4kDirectoryEntry(reader);
if (!string.IsNullOrEmpty(filenamepart) && de.Filename.ToLower( ).Contains(filenamepart.ToLower( )))
{
var p = new p4kFile(de); // FOUND
fileList.Add(p);
}
}
}
return(fileList);
}
/// <summary>
/// Get the filename from the data
/// </summary>
/// <param name="reader">The open and positioned reader</param>
private void ReadFilename(p4kRecReader reader)
{
byte[] fileNameBytes = new byte[m_item.FilenameLength];
fileNameBytes = reader.ReadBytes(m_item.FilenameLength);
m_filename = Encoding.ASCII.GetString(fileNameBytes);
}
//4.3.7 Local file header:
// local file header signature 4 bytes(0x04034b50)
// version needed to extract 2 bytes
// general purpose bit flag 2 bytes
// compression method 2 bytes
// last mod file time 2 bytes
// last mod file date 2 bytes
// crc-32 4 bytes
// compressed size 4 bytes
// uncompressed size 4 bytes
// file name length 2 bytes
// extra field length 2 bytes
// file name( variable size )
// extra field( variable size )
//4.3.8 File data
// Immediately following the local header for a file
// SHOULD be placed the compressed or stored data for the file.
// If the file is encrypted, the encryption header for the file
// SHOULD be placed after the local header and before the file
// data. The series of[local file header][encryption header]
// [file data][data descriptor] repeats for each file in the
// .ZIP archive.
// Zero-byte files, directories, and other file types that
// contain no content MUST not include file data.
// 4.5.3 -Zip64 Extended Information Extra Field(0x0001):
// The following is the layout of the zip64 extended
// information "extra" block.If one of the size or
// offset fields in the Local or Central directory
// record is too small to hold the required data,
// a Zip64 extended information record is created.
// The order of the fields in the zip64 extended
// information record is fixed, but the fields MUST
// only appear if the corresponding Local or Central
// directory record field is set to 0xFFFF or 0xFFFFFFFF.
// Note: all fields stored in Intel low - byte / high - byte order.
// Value Size Description
// ---- - ---------------
//(ZIP64)0x0001 2 bytes Tag for this "extra" block type
// Size 2 bytes Size of this "extra" block
// Original
// Size 8 bytes Original uncompressed file size
// Compressed
// Size 8 bytes Size of compressed data
// Relative Header
// Offset 8 bytes Offset of local header record
// Disk Start
// Number 4 bytes Number of the disk on which
// this file starts
// This entry in the Local header MUST include BOTH original
// and compressed file size fields.If encrypting the
// central directory and bit 13 of the general purpose bit
// flag is set indicating masking, the value stored in the
// Local Header for the original file size will be zero.
/// <summary>
/// ctor: Create class from data returned by the Reader
/// </summary>
/// <param name="reader">A binary data reader for this type of data</param>
public p4kFileHeader(p4kRecReader reader)
{
// sanity check only
System.Diagnostics.Trace.Assert(Marshal.SizeOf(typeof(MyRecord)) == RecordLength,
"Record size does not match!(" + Marshal.SizeOf(typeof(MyRecord)).ToString( ) + ")");
System.Diagnostics.Trace.Assert(Marshal.SizeOf(typeof(MyZ64ExtraRecord)) == Z64ExtraRecordLength,
"Extra Record size does not match!(" + Marshal.SizeOf(typeof(MyZ64ExtraRecord)).ToString( ) + ")");
if (reader.IsOpen( ))
{
try {
long cPos = reader.Position;
do
{
// Fileheaders are Page aligned - scan to find one
reader.AdvancePage( ); // to next page
cPos = reader.Position;
string cPosS = cPos.ToString("X");
m_recordOffset = cPos;
m_item = p4kRecReader.ByteToType <MyRecord>(reader.TheReader);
m_itemValid = m_item.ID.SequenceEqual(p4kSignatures.LocalFileHeaderCry);
} while ((cPos < reader.Length) && !m_itemValid);
// get some file attributes
if (m_itemValid)
{
if (m_item.FilenameLength > 0)
{
ReadFilename(reader);
}
if (m_item.ExtraFieldLength > 0)
{
ReadExtradata(reader); // Likely Zip64 extensions
}
m_fileDateTime = p4kFileTStamp.FromDos(m_item.LastModDate, m_item.LastModTime);
// check if standard fields or extension is used for size information
if (m_item.CompressedSize < 0xffffffff)
{
m_fileSizeComp = m_item.CompressedSize;
m_fileSizeUnComp = m_item.UncompressedSize;
}
else
{
m_fileSizeComp = (long)m_z64Item.CompressedSize;
m_fileSizeUnComp = (long)m_z64Item.UncompressedSize;
}
// now we would be able to read the file content
// but we skip it for now to process the next header
m_fileOffset = reader.TheReader.BaseStream.Position; // save position of this item
reader.TheReader.BaseStream.Seek(m_fileSizeComp, SeekOrigin.Current);
}
else
{
// actually invalid but good manner ..
m_recordOffset = -1;
m_fileOffset = -1;
m_fileSizeComp = 0;
m_fileSizeUnComp = 0;
}
}
catch {
m_itemValid = false;
}
finally {
if (!m_itemValid)
{
if (m_item.ID.SequenceEqual(p4kSignatures.CentralDirRecord))
{
// read beyond the file entries
throw new OperationCanceledException(string.Format("EOF - found Central Directory header {0}", m_item.ID.ToString( )));
}
else
{
// other error
throw new NotSupportedException(string.Format("Cannot process fileheader ID {0}", m_item.ID.ToString( )));
}
}
}
}
}
