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ZipHelperStream.cs
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ZipHelperStream.cs
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using System;
using System.IO;
namespace ICSharpCode.SharpZipLib.Zip
{
/// <summary>
/// Holds data pertinent to a data descriptor.
/// </summary>
public class DescriptorData
{
/// <summary>
/// Get /set the compressed size of data.
/// </summary>
public long CompressedSize
{
get { return compressedSize; }
set { compressedSize = value; }
}
/// <summary>
/// Get / set the uncompressed size of data
/// </summary>
public long Size
{
get { return size; }
set { size = value; }
}
/// <summary>
/// Get /set the crc value.
/// </summary>
public long Crc
{
get { return crc; }
set { crc = (value & 0xffffffff); }
}
#region Instance Fields
private long size;
private long compressedSize;
private long crc;
#endregion Instance Fields
}
internal class EntryPatchData
{
public long SizePatchOffset
{
get { return sizePatchOffset_; }
set { sizePatchOffset_ = value; }
}
public long CrcPatchOffset
{
get { return crcPatchOffset_; }
set { crcPatchOffset_ = value; }
}
#region Instance Fields
private long sizePatchOffset_;
private long crcPatchOffset_;
#endregion Instance Fields
}
/// <summary>
/// This class assists with writing/reading from Zip files.
/// </summary>
internal class ZipHelperStream : Stream
{
#region Constructors
/// <summary>
/// Initialise an instance of this class.
/// </summary>
/// <param name="name">The name of the file to open.</param>
public ZipHelperStream(string name)
{
stream_ = new FileStream(name, FileMode.Open, FileAccess.ReadWrite);
isOwner_ = true;
}
/// <summary>
/// Initialise a new instance of <see cref="ZipHelperStream"/>.
/// </summary>
/// <param name="stream">The stream to use.</param>
public ZipHelperStream(Stream stream)
{
stream_ = stream;
}
#endregion Constructors
/// <summary>
/// Get / set a value indicating whether the underlying stream is owned or not.
/// </summary>
/// <remarks>If the stream is owned it is closed when this instance is closed.</remarks>
public bool IsStreamOwner
{
get { return isOwner_; }
set { isOwner_ = value; }
}
#region Base Stream Methods
public override bool CanRead
{
get { return stream_.CanRead; }
}
public override bool CanSeek
{
get { return stream_.CanSeek; }
}
public override bool CanTimeout
{
get { return stream_.CanTimeout; }
}
public override long Length
{
get { return stream_.Length; }
}
public override long Position
{
get { return stream_.Position; }
set { stream_.Position = value; }
}
public override bool CanWrite
{
get { return stream_.CanWrite; }
}
public override void Flush()
{
stream_.Flush();
}
public override long Seek(long offset, SeekOrigin origin)
{
return stream_.Seek(offset, origin);
}
public override void SetLength(long value)
{
stream_.SetLength(value);
}
public override int Read(byte[] buffer, int offset, int count)
{
return stream_.Read(buffer, offset, count);
}
public override void Write(byte[] buffer, int offset, int count)
{
stream_.Write(buffer, offset, count);
}
/// <summary>
/// Close the stream.
/// </summary>
/// <remarks>
/// The underlying stream is closed only if <see cref="IsStreamOwner"/> is true.
/// </remarks>
protected override void Dispose(bool disposing)
{
Stream toClose = stream_;
stream_ = null;
if (isOwner_ && (toClose != null))
{
isOwner_ = false;
toClose.Dispose();
}
}
#endregion Base Stream Methods
// Write the local file header
// TODO: ZipHelperStream.WriteLocalHeader is not yet used and needs checking for ZipFile and ZipOuptutStream usage
private void WriteLocalHeader(ZipEntry entry, EntryPatchData patchData)
{
CompressionMethod method = entry.CompressionMethod;
bool headerInfoAvailable = true; // How to get this?
bool patchEntryHeader = false;
WriteLEInt(ZipConstants.LocalHeaderSignature);
WriteLEShort(entry.Version);
WriteLEShort(entry.Flags);
WriteLEShort((byte)method);
WriteLEInt((int)entry.DosTime);
if (headerInfoAvailable == true)
{
WriteLEInt((int)entry.Crc);
if (entry.LocalHeaderRequiresZip64)
{
WriteLEInt(-1);
WriteLEInt(-1);
}
else
{
WriteLEInt(entry.IsCrypted ? (int)entry.CompressedSize + ZipConstants.CryptoHeaderSize : (int)entry.CompressedSize);
WriteLEInt((int)entry.Size);
}
}
else
{
if (patchData != null)
{
patchData.CrcPatchOffset = stream_.Position;
}
WriteLEInt(0); // Crc
if (patchData != null)
{
patchData.SizePatchOffset = stream_.Position;
}
// For local header both sizes appear in Zip64 Extended Information
if (entry.LocalHeaderRequiresZip64 && patchEntryHeader)
{
WriteLEInt(-1);
WriteLEInt(-1);
}
else
{
WriteLEInt(0); // Compressed size
WriteLEInt(0); // Uncompressed size
}
}
byte[] name = ZipStrings.ConvertToArray(entry.Flags, entry.Name);
if (name.Length > 0xFFFF)
{
throw new ZipException("Entry name too long.");
}
var ed = new ZipExtraData(entry.ExtraData);
if (entry.LocalHeaderRequiresZip64 && (headerInfoAvailable || patchEntryHeader))
{
ed.StartNewEntry();
if (headerInfoAvailable)
{
ed.AddLeLong(entry.Size);
ed.AddLeLong(entry.CompressedSize);
}
else
{
ed.AddLeLong(-1);
ed.AddLeLong(-1);
}
ed.AddNewEntry(1);
if (!ed.Find(1))
{
throw new ZipException("Internal error cant find extra data");
}
if (patchData != null)
{
patchData.SizePatchOffset = ed.CurrentReadIndex;
}
}
else
{
ed.Delete(1);
}
byte[] extra = ed.GetEntryData();
WriteLEShort(name.Length);
WriteLEShort(extra.Length);
if (name.Length > 0)
{
stream_.Write(name, 0, name.Length);
}
if (entry.LocalHeaderRequiresZip64 && patchEntryHeader)
{
patchData.SizePatchOffset += stream_.Position;
}
if (extra.Length > 0)
{
stream_.Write(extra, 0, extra.Length);
}
}
/// <summary>
/// Locates a block with the desired <paramref name="signature"/>.
/// </summary>
/// <param name="signature">The signature to find.</param>
/// <param name="endLocation">Location, marking the end of block.</param>
/// <param name="minimumBlockSize">Minimum size of the block.</param>
/// <param name="maximumVariableData">The maximum variable data.</param>
/// <returns>Returns the offset of the first byte after the signature; -1 if not found</returns>
public long LocateBlockWithSignature(int signature, long endLocation, int minimumBlockSize, int maximumVariableData)
{
long pos = endLocation - minimumBlockSize;
if (pos < 0)
{
return -1;
}
long giveUpMarker = Math.Max(pos - maximumVariableData, 0);
// TODO: This loop could be optimised for speed.
do
{
if (pos < giveUpMarker)
{
return -1;
}
Seek(pos--, SeekOrigin.Begin);
} while (ReadLEInt() != signature);
return Position;
}
/// <summary>
/// Write Zip64 end of central directory records (File header and locator).
/// </summary>
/// <param name="noOfEntries">The number of entries in the central directory.</param>
/// <param name="sizeEntries">The size of entries in the central directory.</param>
/// <param name="centralDirOffset">The offset of the central directory.</param>
public void WriteZip64EndOfCentralDirectory(long noOfEntries, long sizeEntries, long centralDirOffset)
{
long centralSignatureOffset = centralDirOffset + sizeEntries;
WriteLEInt(ZipConstants.Zip64CentralFileHeaderSignature);
WriteLELong(44); // Size of this record (total size of remaining fields in header or full size - 12)
WriteLEShort(ZipConstants.VersionMadeBy); // Version made by
WriteLEShort(ZipConstants.VersionZip64); // Version to extract
WriteLEInt(0); // Number of this disk
WriteLEInt(0); // number of the disk with the start of the central directory
WriteLELong(noOfEntries); // No of entries on this disk
WriteLELong(noOfEntries); // Total No of entries in central directory
WriteLELong(sizeEntries); // Size of the central directory
WriteLELong(centralDirOffset); // offset of start of central directory
// zip64 extensible data sector not catered for here (variable size)
// Write the Zip64 end of central directory locator
WriteLEInt(ZipConstants.Zip64CentralDirLocatorSignature);
// no of the disk with the start of the zip64 end of central directory
WriteLEInt(0);
// relative offset of the zip64 end of central directory record
WriteLELong(centralSignatureOffset);
// total number of disks
WriteLEInt(1);
}
/// <summary>
/// Write the required records to end the central directory.
/// </summary>
/// <param name="noOfEntries">The number of entries in the directory.</param>
/// <param name="sizeEntries">The size of the entries in the directory.</param>
/// <param name="startOfCentralDirectory">The start of the central directory.</param>
/// <param name="comment">The archive comment. (This can be null).</param>
public void WriteEndOfCentralDirectory(long noOfEntries, long sizeEntries,
long startOfCentralDirectory, byte[] comment)
{
if ((noOfEntries >= 0xffff) ||
(startOfCentralDirectory >= 0xffffffff) ||
(sizeEntries >= 0xffffffff))
{
WriteZip64EndOfCentralDirectory(noOfEntries, sizeEntries, startOfCentralDirectory);
}
WriteLEInt(ZipConstants.EndOfCentralDirectorySignature);
// TODO: ZipFile Multi disk handling not done
WriteLEShort(0); // number of this disk
WriteLEShort(0); // no of disk with start of central dir
// Number of entries
if (noOfEntries >= 0xffff)
{
WriteLEUshort(0xffff); // Zip64 marker
WriteLEUshort(0xffff);
}
else
{
WriteLEShort((short)noOfEntries); // entries in central dir for this disk
WriteLEShort((short)noOfEntries); // total entries in central directory
}
// Size of the central directory
if (sizeEntries >= 0xffffffff)
{
WriteLEUint(0xffffffff); // Zip64 marker
}
else
{
WriteLEInt((int)sizeEntries);
}
// offset of start of central directory
if (startOfCentralDirectory >= 0xffffffff)
{
WriteLEUint(0xffffffff); // Zip64 marker
}
else
{
WriteLEInt((int)startOfCentralDirectory);
}
int commentLength = (comment != null) ? comment.Length : 0;
if (commentLength > 0xffff)
{
throw new ZipException(string.Format("Comment length({0}) is too long can only be 64K", commentLength));
}
WriteLEShort(commentLength);
if (commentLength > 0)
{
Write(comment, 0, comment.Length);
}
}
#region LE value reading/writing
/// <summary>
/// Read an unsigned short in little endian byte order.
/// </summary>
/// <returns>Returns the value read.</returns>
/// <exception cref="IOException">
/// An i/o error occurs.
/// </exception>
/// <exception cref="EndOfStreamException">
/// The file ends prematurely
/// </exception>
public int ReadLEShort()
{
int byteValue1 = stream_.ReadByte();
if (byteValue1 < 0)
{
throw new EndOfStreamException();
}
int byteValue2 = stream_.ReadByte();
if (byteValue2 < 0)
{
throw new EndOfStreamException();
}
return byteValue1 | (byteValue2 << 8);
}
/// <summary>
/// Read an int in little endian byte order.
/// </summary>
/// <returns>Returns the value read.</returns>
/// <exception cref="IOException">
/// An i/o error occurs.
/// </exception>
/// <exception cref="System.IO.EndOfStreamException">
/// The file ends prematurely
/// </exception>
public int ReadLEInt()
{
return ReadLEShort() | (ReadLEShort() << 16);
}
/// <summary>
/// Read a long in little endian byte order.
/// </summary>
/// <returns>The value read.</returns>
public long ReadLELong()
{
return (uint)ReadLEInt() | ((long)ReadLEInt() << 32);
}
/// <summary>
/// Write an unsigned short in little endian byte order.
/// </summary>
/// <param name="value">The value to write.</param>
public void WriteLEShort(int value)
{
stream_.WriteByte((byte)(value & 0xff));
stream_.WriteByte((byte)((value >> 8) & 0xff));
}
/// <summary>
/// Write a ushort in little endian byte order.
/// </summary>
/// <param name="value">The value to write.</param>
public void WriteLEUshort(ushort value)
{
stream_.WriteByte((byte)(value & 0xff));
stream_.WriteByte((byte)(value >> 8));
}
/// <summary>
/// Write an int in little endian byte order.
/// </summary>
/// <param name="value">The value to write.</param>
public void WriteLEInt(int value)
{
WriteLEShort(value);
WriteLEShort(value >> 16);
}
/// <summary>
/// Write a uint in little endian byte order.
/// </summary>
/// <param name="value">The value to write.</param>
public void WriteLEUint(uint value)
{
WriteLEUshort((ushort)(value & 0xffff));
WriteLEUshort((ushort)(value >> 16));
}
/// <summary>
/// Write a long in little endian byte order.
/// </summary>
/// <param name="value">The value to write.</param>
public void WriteLELong(long value)
{
WriteLEInt((int)value);
WriteLEInt((int)(value >> 32));
}
/// <summary>
/// Write a ulong in little endian byte order.
/// </summary>
/// <param name="value">The value to write.</param>
public void WriteLEUlong(ulong value)
{
WriteLEUint((uint)(value & 0xffffffff));
WriteLEUint((uint)(value >> 32));
}
#endregion LE value reading/writing
/// <summary>
/// Write a data descriptor.
/// </summary>
/// <param name="entry">The entry to write a descriptor for.</param>
/// <returns>Returns the number of descriptor bytes written.</returns>
public int WriteDataDescriptor(ZipEntry entry)
{
if (entry == null)
{
throw new ArgumentNullException(nameof(entry));
}
int result = 0;
// Add data descriptor if flagged as required
if ((entry.Flags & (int)GeneralBitFlags.Descriptor) != 0)
{
// The signature is not PKZIP originally but is now described as optional
// in the PKZIP Appnote documenting the format.
WriteLEInt(ZipConstants.DataDescriptorSignature);
WriteLEInt(unchecked((int)(entry.Crc)));
result += 8;
if (entry.LocalHeaderRequiresZip64)
{
WriteLELong(entry.CompressedSize);
WriteLELong(entry.Size);
result += 16;
}
else
{
WriteLEInt((int)entry.CompressedSize);
WriteLEInt((int)entry.Size);
result += 8;
}
}
return result;
}
/// <summary>
/// Read data descriptor at the end of compressed data.
/// </summary>
/// <param name="zip64">if set to <c>true</c> [zip64].</param>
/// <param name="data">The data to fill in.</param>
/// <returns>Returns the number of bytes read in the descriptor.</returns>
public void ReadDataDescriptor(bool zip64, DescriptorData data)
{
int intValue = ReadLEInt();
// In theory this may not be a descriptor according to PKZIP appnote.
// In practice its always there.
if (intValue != ZipConstants.DataDescriptorSignature)
{
throw new ZipException("Data descriptor signature not found");
}
data.Crc = ReadLEInt();
if (zip64)
{
data.CompressedSize = ReadLELong();
data.Size = ReadLELong();
}
else
{
data.CompressedSize = ReadLEInt();
data.Size = ReadLEInt();
}
}
#region Instance Fields
private bool isOwner_;
private Stream stream_;
#endregion Instance Fields
}
}