ZipEndOfCentralDirectoryBlock.cs

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namespace System.IO.Compression;
 
internal struct ZipEndOfCentralDirectoryBlock
{
    public uint Signature;
 
    public ushort NumberOfThisDisk;
 
    public ushort NumberOfTheDiskWithTheStartOfTheCentralDirectory;
 
    public ushort NumberOfEntriesInTheCentralDirectoryOnThisDisk;
 
    public ushort NumberOfEntriesInTheCentralDirectory;
 
    public uint SizeOfCentralDirectory;
 
    public uint OffsetOfStartOfCentralDirectoryWithRespectToTheStartingDiskNumber;
 
    public byte[] ArchiveComment;
 
    public static void WriteBlock(Stream stream, long numberOfEntries, long startOfCentralDirectory, long sizeOfCentralDirectory, byte[] archiveComment)
    {
        BinaryWriter binaryWriter = new BinaryWriter(stream);
        ushort value = ((numberOfEntries > 65535) ? ushort.MaxValue : ((ushort)numberOfEntries));
        uint value2 = (uint)((startOfCentralDirectory > uint.MaxValue) ? uint.MaxValue : startOfCentralDirectory);
        uint value3 = (uint)((sizeOfCentralDirectory > uint.MaxValue) ? uint.MaxValue : sizeOfCentralDirectory);
        binaryWriter.Write(101010256u);
        binaryWriter.Write((ushort)0);
        binaryWriter.Write((ushort)0);
        binaryWriter.Write(value);
        binaryWriter.Write(value);
        binaryWriter.Write(value3);
        binaryWriter.Write(value2);
        binaryWriter.Write((ushort)((archiveComment != null) ? ((ushort)archiveComment.Length) : 0));
        if (archiveComment != null)
        {
            binaryWriter.Write(archiveComment);
        }
    }
 
    public static bool TryReadBlock(BinaryReader reader, out ZipEndOfCentralDirectoryBlock eocdBlock)
    {
        eocdBlock = default(ZipEndOfCentralDirectoryBlock);
        if (reader.ReadUInt32() != 101010256)
        {
            return false;
        }
        eocdBlock.Signature = 101010256u;
        eocdBlock.NumberOfThisDisk = reader.ReadUInt16();
        eocdBlock.NumberOfTheDiskWithTheStartOfTheCentralDirectory = reader.ReadUInt16();
        eocdBlock.NumberOfEntriesInTheCentralDirectoryOnThisDisk = reader.ReadUInt16();
        eocdBlock.NumberOfEntriesInTheCentralDirectory = reader.ReadUInt16();
        eocdBlock.SizeOfCentralDirectory = reader.ReadUInt32();
        eocdBlock.OffsetOfStartOfCentralDirectoryWithRespectToTheStartingDiskNumber = reader.ReadUInt32();
        ushort count = reader.ReadUInt16();
        eocdBlock.ArchiveComment = reader.ReadBytes(count);
        return true;
    }
}