System.IO.Compression.ZipStorer.DateTimeToDosTime C# (CSharp) Méthode

        private uint DateTimeToDosTime(DateTime _dt)
        {
            return (uint)(
                (_dt.Second / 2) | (_dt.Minute << 5) | (_dt.Hour << 11) |
                (_dt.Day<<16) | (_dt.Month << 21) | ((_dt.Year - 1980) << 25));
        }

        private void WriteCentralDirRecord(ZipStorer.ZipFileEntry zipFileEntry)
        {
            Encoding encoding = zipFileEntry.EncodeUTF8 ? Encoding.UTF8 : ZipStorer.defaultEncoding;

            byte[] bytes  = encoding.GetBytes(zipFileEntry.FilenameInZip);
            byte[] bytes2 = encoding.GetBytes(zipFileEntry.Comment);
            this.zipFileStream.Write(new byte[]
            {
                80,
                75,
                1,
                2,
                23,
                11,
                20,
                0
            }, 0, 8);
            this.zipFileStream.Write(BitConverter.GetBytes(zipFileEntry.EncodeUTF8 ? 2048 : 0), 0, 2);
            this.zipFileStream.Write(BitConverter.GetBytes((ushort)zipFileEntry.Method), 0, 2);
            this.zipFileStream.Write(BitConverter.GetBytes(ZipStorer.DateTimeToDosTime(zipFileEntry.ModifyTime)), 0, 4);
            this.zipFileStream.Write(BitConverter.GetBytes(zipFileEntry.Crc32), 0, 4);
            this.zipFileStream.Write(BitConverter.GetBytes(zipFileEntry.CompressedSize), 0, 4);
            this.zipFileStream.Write(BitConverter.GetBytes(zipFileEntry.FileSize), 0, 4);
            this.zipFileStream.Write(BitConverter.GetBytes((ushort)bytes.Length), 0, 2);
            this.zipFileStream.Write(BitConverter.GetBytes(0), 0, 2);
            this.zipFileStream.Write(BitConverter.GetBytes((ushort)bytes2.Length), 0, 2);
            this.zipFileStream.Write(BitConverter.GetBytes(0), 0, 2);
            this.zipFileStream.Write(BitConverter.GetBytes(0), 0, 2);
            this.zipFileStream.Write(BitConverter.GetBytes(0), 0, 2);
            this.zipFileStream.Write(BitConverter.GetBytes(33024), 0, 2);
            this.zipFileStream.Write(BitConverter.GetBytes(zipFileEntry.HeaderOffset), 0, 4);
            this.zipFileStream.Write(bytes, 0, bytes.Length);
            this.zipFileStream.Write(bytes2, 0, bytes2.Length);
        }