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Fix Zip64 implementation (2) #64

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Fix Zip64 implementation (2) #64

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e3ef154
Fix Zip64 implementation (2)
thomas694 Jan 21, 2025
b7732f5
Add extra: Test method to test Zip64 functionality
thomas694 Jan 24, 2025
18db789
fix free disk space check
thomas694 Jan 25, 2025
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Fix Zip64 implementation (2)
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@thomas694
thomas694 committed Jan 21, 2025
commit e3ef1546f9af58bc2e9fdf47fe0e89e9b88fc08e
97 changes: 65 additions & 32 deletions src/ZipStorer.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -29,31 +29,31 @@ public enum Compression : ushort
public class ZipFileEntry
{
/// <summary>Compression method</summary>
public Compression Method {get; set;}
public Compression Method { get; set; }
/// <summary>Full path and filename as stored in Zip</summary>
public string FilenameInZip {get; set;}
public string FilenameInZip { get; set; }
/// <summary>Original file size</summary>
public long FileSize {get; set;}
public long FileSize { get; set; }
/// <summary>Compressed file size</summary>
public long CompressedSize {get; set;}
public long CompressedSize { get; set; }
/// <summary>Offset of header information inside Zip storage</summary>
public long HeaderOffset {get; set;}
public long HeaderOffset { get; set; }
/// <summary>Offset of file inside Zip storage</summary>
public long FileOffset {get; set;}
public long FileOffset { get; set; }
/// <summary>Size of header information</summary>
public uint HeaderSize {get; set;}
public uint HeaderSize { get; set; }
/// <summary>32-bit checksum of entire file</summary>
public uint Crc32 {get; set;}
public uint Crc32 { get; set; }
/// <summary>Last modification time of file</summary>
public DateTime ModifyTime {get; set;}
public DateTime ModifyTime { get; set; }
/// <summary>Creation time of file</summary>
public DateTime CreationTime {get; set;}
public DateTime CreationTime { get; set; }
/// <summary>Last access time of file</summary>
public DateTime AccessTime {get; set;}
public DateTime AccessTime { get; set; }
/// <summary>User comment for file</summary>
public string Comment {get; set;}
public string Comment { get; set; }
/// <summary>True if UTF8 encoding for filename and comments, false if default (CP 437)</summary>
public bool EncodeUTF8 {get; set;}
public bool EncodeUTF8 { get; set; }

/// <summary>Overriden method</summary>
/// <returns>Filename in Zip</returns>
Expand All @@ -63,14 +63,14 @@ public override string ToString()
}
}

#region Public properties
#region Public properties
/// <summary>True if UTF8 encoding for filename and comments, false if default (CP 437)</summary>
public bool EncodeUTF8 {get; set;} = false;
public bool EncodeUTF8 { get; set; } = false;
/// <summary>Force deflate algotithm even if it inflates the stored file. Off by default.</summary>
public bool ForceDeflating {get; set;} = false;
#endregion
public bool ForceDeflating { get; set; } = false;
#endregion

#region Private fields
#region Private fields
// List of files to store
private List<ZipFileEntry> Files = new List<ZipFileEntry>();
// Filename of storage file
Expand All @@ -93,9 +93,9 @@ public override string ToString()
private static Encoding DefaultEncoding;
// leave the stream open after the ZipStorer object is disposed
private bool LeaveOpen;
#endregion
#endregion

#region Public methods
#region Public methods
static ZipStorer()
{
// Generate CRC32 table
Expand Down Expand Up @@ -267,6 +267,7 @@ public async Task<ZipFileEntry> AddStreamAsync(Compression method, string filena
Method = method,
EncodeUTF8 = this.EncodeUTF8,
FilenameInZip = NormalizedFilename(filenameInZip),
FileSize = !source.CanSeek || ForceDeflating ? 0 : source.Length,
Comment = comment ?? string.Empty,
Crc32 = 0, // to be updated later
HeaderOffset = this.ZipFileStream.Position, // offset within file of the start of this local record
Expand Down Expand Up @@ -604,9 +605,9 @@ public static bool RemoveEntries(ref ZipStorer zip, List<ZipFileEntry> zfes)
}
return true;
}
#endregion
#endregion

#region Private methods
#region Private methods
// Calculate the file offset by reading the corresponding local header
private long GetFileOffset(long _headerOffset)
{
Expand Down Expand Up @@ -904,9 +905,9 @@ private static uint DateTimeToDosTime(DateTime _dt)

private static byte[] CreateExtraInfo(ZipFileEntry _zfe, bool localHeader)
{
var zip64FileSize = _zfe.FileSize >= 0xFFFFFFFF || localHeader && _zfe.CompressedSize >= 0xFFFFFFFF;
var zip64CompSize = _zfe.CompressedSize >= 0xFFFFFFFF || localHeader && _zfe.FileSize >= 0xFFFFFFFF;
var zip64Offset = _zfe.HeaderOffset >= 0xFFFFFFFF;
var zip64FileSize = _zfe.FileSize >= 0xFFFFFFFF || localHeader && _zfe.FileSize == 0;
var zip64CompSize = _zfe.CompressedSize >= 0xFFFFFFFF || localHeader && (_zfe.FileSize == 0 || _zfe.FileSize >= 0xFFFFFFFF);
var zip64Offset = !localHeader && _zfe.HeaderOffset >= 0xFFFFFFFF;

int offset = (zip64FileSize ? 8 : 0) + (zip64CompSize ? 8 : 0) + (zip64Offset ? 8 : 0);
if (offset != 0) offset += 4;
Expand Down Expand Up @@ -990,8 +991,6 @@ value is put in the data descriptor and in the central directory.
*/
private void UpdateCrcAndSizes(ZipFileEntry _zfe)
{
var zip64Sizes = IsZip64ExtNeeded(_zfe, 1);

long lastPos = this.ZipFileStream.Position; // remember position

this.ZipFileStream.Position = _zfe.HeaderOffset + 4;
Expand All @@ -1000,17 +999,51 @@ private void UpdateCrcAndSizes(ZipFileEntry _zfe)
this.ZipFileStream.Position = _zfe.HeaderOffset + 8;
this.ZipFileStream.Write(BitConverter.GetBytes((ushort)_zfe.Method), 0, 2); // zipping method

var zip64Sizes = UpdateLocalHeaderExtraFields(_zfe);

this.ZipFileStream.Position = _zfe.HeaderOffset + 14;

this.ZipFileStream.Write(BitConverter.GetBytes(_zfe.Crc32), 0, 4); // Update CRC
this.ZipFileStream.Write(BitConverter.GetBytes(zip64Sizes ? 0xFFFFFFFF : _zfe.CompressedSize), 0, 4); // Compressed size
this.ZipFileStream.Write(BitConverter.GetBytes(zip64Sizes ? 0xFFFFFFFF : _zfe.FileSize), 0, 4); // Uncompressed size

// and updating the extra fields?

this.ZipFileStream.Position = lastPos; // restore position
}

private bool UpdateLocalHeaderExtraFields(ZipFileEntry _zfe)
{
this.ZipFileStream.Position = _zfe.HeaderOffset + 26;

bool zip64Sizes = false;
var buffer = new byte[4];
this.ZipFileStream.Read(buffer, 0, 4);
var fileNameLength = BitConverter.ToUInt16(buffer, 0);
var extraFieldLength = BitConverter.ToUInt16(buffer, 2);
if (extraFieldLength > 0)
{
this.ZipFileStream.Seek(fileNameLength, SeekOrigin.Current);
var extraFieldsBuffer = new byte[extraFieldLength];
this.ZipFileStream.Read(extraFieldsBuffer, 0, extraFieldLength);

int pos = 0;
while (pos < extraFieldsBuffer.Length - 4)
{
uint extraId = BitConverter.ToUInt16(extraFieldsBuffer, pos);
uint length = BitConverter.ToUInt16(extraFieldsBuffer, pos + 2);

if (extraId == 0x0001) // ZIP64 Information
{
zip64Sizes = true;
this.ZipFileStream.Position = _zfe.HeaderOffset + 30 + fileNameLength + 4 + pos;
this.ZipFileStream.Write(BitConverter.GetBytes((ulong)_zfe.FileSize), 0, 8);
this.ZipFileStream.Write(BitConverter.GetBytes((ulong)_zfe.CompressedSize), 0, 8);
}
pos += (int)length + 4;
}
}
return zip64Sizes;
}

// Replaces backslashes with slashes to store in zip header
private static string NormalizedFilename(string filename)
{
Expand Down Expand Up @@ -1107,9 +1140,9 @@ private bool ReadFileInfo()

return false;
}
#endregion
#endregion

#region IDisposable implementation
#region IDisposable implementation
/// <summary>
/// Closes the Zip file stream
/// </summary>
Expand All @@ -1130,6 +1163,6 @@ protected virtual void Dispose(bool disposing)
IsDisposed = true;
}
}
#endregion
#endregion
}
}