ARJ.cs

using System;
using System.Collections.Generic;
using System.IO;
using System.Text;

namespace ARJ
{
    class ARJ
    {
        public class ArjFileHeader
        {
            public byte Size;
            public byte Version;
            public byte ExtraVersion;
            public byte HostOs;
            public byte Flags;
            public byte CompressionMethod;
            public byte FileType;
            public byte Reserved1;
            public uint LastModifiedTime;
            public uint CompressedFileSize;
            public uint OriginalFileSize;
            public uint OriginalFileCRC;
            public ushort AccesMode;
            public ushort FileSpec;
            public ushort HostData;
            public uint ExtraData;
            public uint AccessTime;
            public uint CreationTime;
            public uint VolumeSize;

            public ArjFileHeader(FileInfo file, uint fileCrc)
            {               
                this.Version = 0x66;
                this.ExtraVersion = 0x01;
                this.HostOs = 0x0B;
                this.Flags = 0x10;
                this.CompressionMethod = 0x00;
                this.FileType = 0x00;
                this.Reserved1 = 0x95;
                this.CreationTime = (uint)ToDOSDate(file.CreationTime);
                this.LastModifiedTime = (uint)ToDOSDate(file.LastWriteTime);
                this.CompressedFileSize = (uint)file.Length;
                this.OriginalFileSize = (uint)file.Length;
                this.OriginalFileCRC = fileCrc;
                this.AccesMode = 0x0020;
                this.FileSpec = 0x0000;
                this.HostData = 0x0000;
                this.ExtraData = 0x0000;
                this.AccessTime = (uint)ToDOSDate(file.LastAccessTime);
                this.VolumeSize = (uint)file.Length;

                this.Size = (byte)(this.GetSize());
            }

            public byte[] GetBytes()
            {
                using (MemoryStream memoryStream = new MemoryStream())
                {
                    using (BinaryWriter binaryWriter = new BinaryWriter(memoryStream))
                    {
                        binaryWriter.Write(this.Size);
                        binaryWriter.Write(this.Version);
                        binaryWriter.Write(this.ExtraVersion);
                        binaryWriter.Write(this.HostOs);
                        binaryWriter.Write(this.Flags);
                        binaryWriter.Write(this.CompressionMethod);
                        binaryWriter.Write(this.FileType);
                        binaryWriter.Write(this.Reserved1);
                        binaryWriter.Write(this.LastModifiedTime);
                        binaryWriter.Write(this.CompressedFileSize);
                        binaryWriter.Write(this.OriginalFileSize);
                        binaryWriter.Write(this.OriginalFileCRC);
                        binaryWriter.Write(this.FileSpec);
                        binaryWriter.Write(this.AccesMode);
                        binaryWriter.Write(this.HostData);
                        binaryWriter.Write(this.ExtraData);
                        binaryWriter.Write(this.AccessTime);
                        binaryWriter.Write(this.CreationTime);
                        binaryWriter.Write(this.VolumeSize);

                        binaryWriter.Flush();
                    }

                    return memoryStream.ToArray();
                }
            }

            public byte GetSize()
            {
                return (byte)this.GetBytes().Length;
            }
        }

        public class ArjBasicFileHeader
        {
            public ArjFileHeader FileHeader;
            public string FileName;
            public byte Comment = 0x00;

            public ArjBasicFileHeader(FileInfo file,  string output, uint fileSize, uint fileCrc)
            {
                this.FileName = output;
                this.FileHeader = new ArjFileHeader(file, fileCrc);

                this.GetBytes();
            }

            public byte[] GetBytes()
            {
                using (MemoryStream memoryStream = new MemoryStream())
                {
                    using (BinaryWriter binaryWriter = new BinaryWriter(memoryStream))
                    {
                        binaryWriter.Write(this.FileHeader.GetBytes());
                        binaryWriter.Write(Encoding.ASCII.GetBytes(this.FileName));
                        binaryWriter.Write((byte)0x00);
                        binaryWriter.Write(this.Comment);

                        binaryWriter.Flush();
                    }

                    return memoryStream.ToArray();
                }
            }
        }

        public class ArjMainFileHeader
        {
            public ushort Magic = 0xEA60;
            public ushort BasicHeaderSize;
            public ArjBasicFileHeader BasicHeader;
            public uint BasicHeaderCrc;
            public ushort ExtraHeaders;
            public byte[] FileData;

            public ArjMainFileHeader(FileInfo file, string output)
            {                
                if (!file.Exists)
                {
                    return;
                }

                this.FileData = File.ReadAllBytes(file.FullName);
                int fileSize = this.FileData.Length;
                uint fileCrc = crc32(this.FileData);

                this.BasicHeader = new ArjBasicFileHeader(file, output, (uint) fileSize, fileCrc);
                this.BasicHeaderSize = (ushort)(this.BasicHeader.GetBytes().Length);

                this.BasicHeaderCrc = crc32(this.BasicHeader.GetBytes());

                this.ExtraHeaders = 0x0000;

                this.GetBytes();
            }

            public byte[] GetBytes()
            {
                using (MemoryStream memoryStream = new MemoryStream())
                {
                    using (BinaryWriter binaryWriter = new BinaryWriter(memoryStream))
                    {
                        binaryWriter.Write(this.Magic);
                        binaryWriter.Write(this.BasicHeaderSize);
                        binaryWriter.Write(this.BasicHeader.GetBytes());
                        binaryWriter.Write(this.BasicHeaderCrc);
                        binaryWriter.Write(this.ExtraHeaders);

                        binaryWriter.Write(this.FileData);

                        binaryWriter.Write(this.Magic);
                        binaryWriter.Write((ushort)0);

                        binaryWriter.Flush();
                    }

                    return memoryStream.ToArray();
                }
            }
        }

        public class ArjFirstHeader
        {
            public byte Size;
            public byte Version;
            public byte ExtraVersion;
            public byte HostOs;
            public byte Flags;
            public byte SecurityVersion;
            public byte FileType;
            public byte Reserved1;
            public uint CreationTime;
            public uint LastModifiedTime;
            public uint ArchiveSize;
            public uint SecurityEnvelopePosition;
            public ushort FileSpec;
            public short SecurityEnvelopeSize;
            public ushort Reserved2;
            public uint ExtraData;

            public ArjFirstHeader()
            {
                this.Version = 0x66;
                this.ExtraVersion = 0x01;
                this.HostOs = 0x0B;
                this.Flags = 0x10;
                this.SecurityVersion = 0x00;
                this.FileType = 0x02;
                this.Reserved1 = 0x95;
                this.CreationTime = 0x4E5BB395;
                this.LastModifiedTime = 0x4E5BB395;
                this.ArchiveSize = 0x00000000;
                this.SecurityEnvelopePosition = 0x00000000;
                this.FileSpec = 0x0000;
                this.SecurityEnvelopeSize = 0x0000;
                this.Reserved2 = 0x0000;
                this.ExtraData = 0x00000000;

                this.Size = (byte)(this.GetSize() /*- Marshal.SizeOf(this.Size)*/);
            }

            public byte[] GetBytes()
            {
                using (MemoryStream memoryStream = new MemoryStream())
                {
                    using (BinaryWriter binaryWriter = new BinaryWriter(memoryStream))
                    {
                        binaryWriter.Write(this.Size);
                        binaryWriter.Write(this.Version);
                        binaryWriter.Write(this.ExtraVersion);
                        binaryWriter.Write(this.HostOs);
                        binaryWriter.Write(this.Flags);
                        binaryWriter.Write(this.SecurityVersion);
                        binaryWriter.Write(this.FileType);
                        binaryWriter.Write(this.Reserved1);
                        binaryWriter.Write(this.CreationTime);
                        binaryWriter.Write(this.LastModifiedTime);
                        binaryWriter.Write(this.ArchiveSize);
                        binaryWriter.Write(this.SecurityEnvelopePosition);
                        binaryWriter.Write(this.FileSpec);
                        binaryWriter.Write(this.SecurityEnvelopeSize);
                        binaryWriter.Write(this.Reserved2);
                        binaryWriter.Write(this.ExtraData);

                        binaryWriter.Flush();
                    }

                    return memoryStream.ToArray();
                }
            }

            public byte GetSize()
            {
                return (byte)this.GetBytes().Length;
            }
        }


        public class ArjBasicHeader
        {
            public ArjFirstHeader FirstHeader;
            public string FileName;
            public byte Comment = 0x00;

            public ArjBasicHeader(string filename)
            {
                this.FileName = filename;
                this.FirstHeader = new ArjFirstHeader();

                this.GetBytes();
            }

            public byte[] GetBytes()
            {
                using (MemoryStream memoryStream = new MemoryStream())
                {
                    using (BinaryWriter binaryWriter = new BinaryWriter(memoryStream))
                    {
                        binaryWriter.Write(this.FirstHeader.GetBytes());
                        binaryWriter.Write(Encoding.ASCII.GetBytes(this.FileName));
                        binaryWriter.Write((byte)0x00);
                        binaryWriter.Write(this.Comment);

                        binaryWriter.Flush();
                    }

                    return memoryStream.ToArray();
                }
            }
        }

        public class ArjMainHeader
        {
            public ushort Magic = 0xEA60;
            public ushort BasicHeaderSize;
            public ArjBasicHeader BasicHeader;
            public uint BasicHeaderCrc;
            public ushort ExtraHeaders;

            public ArjMainHeader(string filename)
            {
                this.BasicHeader = new ArjBasicHeader(filename);
                this.BasicHeaderSize = (ushort)(this.BasicHeader.GetBytes().Length);

                this.BasicHeaderCrc = crc32(this.BasicHeader.GetBytes());

                this.ExtraHeaders = 0x0000;

                this.GetBytes();
            }

            public byte[] GetBytes()
            {
                using (MemoryStream memoryStream = new MemoryStream())
                {
                    using (BinaryWriter binaryWriter = new BinaryWriter(memoryStream))
                    {
                        binaryWriter.Write(this.Magic);
                        binaryWriter.Write(this.BasicHeaderSize);
                        binaryWriter.Write(this.BasicHeader.GetBytes());
                        binaryWriter.Write(this.BasicHeaderCrc);
                        binaryWriter.Write(this.ExtraHeaders);

                        binaryWriter.Flush();
                    }

                    return memoryStream.ToArray();
                }
            }
        }        

        //https://stackoverflow.com/questions/11895382/net-datetime-to-dos-date-32-bit-conversion
        public static DateTime ToDateTime(int dosDateTime)
        {
            var date = (dosDateTime & 0xFFFF0000) >> 16;
            var time = (dosDateTime & 0x0000FFFF);

            var year = (date >> 9) + 1980;
            var month = (date & 0x01e0) >> 5;
            var day = date & 0x1F;
            var hour = time >> 11;
            var minute = (time & 0x07e0) >> 5;
            var second = (time & 0x1F) * 2;

            return new DateTime((int)year, (int)month, (int)day, (int)hour, (int)minute, (int)second);
        }

        public static int ToDOSDate(DateTime dateTime)
        {
            var years = dateTime.Year - 1980;
            var months = dateTime.Month;
            var days = dateTime.Day;
            var hours = dateTime.Hour;
            var minutes = dateTime.Minute;
            var seconds = dateTime.Second + 1;

            var date = (years << 9) | (months << 5) | days;
            var time = (hours << 11) | (minutes << 5) | (seconds >> 1);

            return (date << 16) | time;
        }

        // https://stackoverflow.com/a/21176004
        public static uint crc32(byte[] input)
        {
            var table = new uint[]{
            0x00000000, 0x77073096, 0xEE0E612C, 0x990951BA, 0x076DC419, 0x706AF48F,
                0xE963A535, 0x9E6495A3, 0x0EDB8832, 0x79DCB8A4, 0xE0D5E91E, 0x97D2D988,
                0x09B64C2B, 0x7EB17CBD, 0xE7B82D07, 0x90BF1D91, 0x1DB71064, 0x6AB020F2,
                0xF3B97148, 0x84BE41DE, 0x1ADAD47D, 0x6DDDE4EB, 0xF4D4B551, 0x83D385C7,
                0x136C9856, 0x646BA8C0, 0xFD62F97A, 0x8A65C9EC, 0x14015C4F, 0x63066CD9,
                0xFA0F3D63, 0x8D080DF5, 0x3B6E20C8, 0x4C69105E, 0xD56041E4, 0xA2677172,
                0x3C03E4D1, 0x4B04D447, 0xD20D85FD, 0xA50AB56B, 0x35B5A8FA, 0x42B2986C,
                0xDBBBC9D6, 0xACBCF940, 0x32D86CE3, 0x45DF5C75, 0xDCD60DCF, 0xABD13D59,
                0x26D930AC, 0x51DE003A, 0xC8D75180, 0xBFD06116, 0x21B4F4B5, 0x56B3C423,
                0xCFBA9599, 0xB8BDA50F, 0x2802B89E, 0x5F058808, 0xC60CD9B2, 0xB10BE924,
                0x2F6F7C87, 0x58684C11, 0xC1611DAB, 0xB6662D3D, 0x76DC4190, 0x01DB7106,
                0x98D220BC, 0xEFD5102A, 0x71B18589, 0x06B6B51F, 0x9FBFE4A5, 0xE8B8D433,
                0x7807C9A2, 0x0F00F934, 0x9609A88E, 0xE10E9818, 0x7F6A0DBB, 0x086D3D2D,
                0x91646C97, 0xE6635C01, 0x6B6B51F4, 0x1C6C6162, 0x856530D8, 0xF262004E,
                0x6C0695ED, 0x1B01A57B, 0x8208F4C1, 0xF50FC457, 0x65B0D9C6, 0x12B7E950,
                0x8BBEB8EA, 0xFCB9887C, 0x62DD1DDF, 0x15DA2D49, 0x8CD37CF3, 0xFBD44C65,
                0x4DB26158, 0x3AB551CE, 0xA3BC0074, 0xD4BB30E2, 0x4ADFA541, 0x3DD895D7,
                0xA4D1C46D, 0xD3D6F4FB, 0x4369E96A, 0x346ED9FC, 0xAD678846, 0xDA60B8D0,
                0x44042D73, 0x33031DE5, 0xAA0A4C5F, 0xDD0D7CC9, 0x5005713C, 0x270241AA,
                0xBE0B1010, 0xC90C2086, 0x5768B525, 0x206F85B3, 0xB966D409, 0xCE61E49F,
                0x5EDEF90E, 0x29D9C998, 0xB0D09822, 0xC7D7A8B4, 0x59B33D17, 0x2EB40D81,
                0xB7BD5C3B, 0xC0BA6CAD, 0xEDB88320, 0x9ABFB3B6, 0x03B6E20C, 0x74B1D29A,
                0xEAD54739, 0x9DD277AF, 0x04DB2615, 0x73DC1683, 0xE3630B12, 0x94643B84,
                0x0D6D6A3E, 0x7A6A5AA8, 0xE40ECF0B, 0x9309FF9D, 0x0A00AE27, 0x7D079EB1,
                0xF00F9344, 0x8708A3D2, 0x1E01F268, 0x6906C2FE, 0xF762575D, 0x806567CB,
                0x196C3671, 0x6E6B06E7, 0xFED41B76, 0x89D32BE0, 0x10DA7A5A, 0x67DD4ACC,
                0xF9B9DF6F, 0x8EBEEFF9, 0x17B7BE43, 0x60B08ED5, 0xD6D6A3E8, 0xA1D1937E,
                0x38D8C2C4, 0x4FDFF252, 0xD1BB67F1, 0xA6BC5767, 0x3FB506DD, 0x48B2364B,
                0xD80D2BDA, 0xAF0A1B4C, 0x36034AF6, 0x41047A60, 0xDF60EFC3, 0xA867DF55,
                0x316E8EEF, 0x4669BE79, 0xCB61B38C, 0xBC66831A, 0x256FD2A0, 0x5268E236,
                0xCC0C7795, 0xBB0B4703, 0x220216B9, 0x5505262F, 0xC5BA3BBE, 0xB2BD0B28,
                0x2BB45A92, 0x5CB36A04, 0xC2D7FFA7, 0xB5D0CF31, 0x2CD99E8B, 0x5BDEAE1D,
                0x9B64C2B0, 0xEC63F226, 0x756AA39C, 0x026D930A, 0x9C0906A9, 0xEB0E363F,
                0x72076785, 0x05005713, 0x95BF4A82, 0xE2B87A14, 0x7BB12BAE, 0x0CB61B38,
                0x92D28E9B, 0xE5D5BE0D, 0x7CDCEFB7, 0x0BDBDF21, 0x86D3D2D4, 0xF1D4E242,
                0x68DDB3F8, 0x1FDA836E, 0x81BE16CD, 0xF6B9265B, 0x6FB077E1, 0x18B74777,
                0x88085AE6, 0xFF0F6A70, 0x66063BCA, 0x11010B5C, 0x8F659EFF, 0xF862AE69,
                0x616BFFD3, 0x166CCF45, 0xA00AE278, 0xD70DD2EE, 0x4E048354, 0x3903B3C2,
                0xA7672661, 0xD06016F7, 0x4969474D, 0x3E6E77DB, 0xAED16A4A, 0xD9D65ADC,
                0x40DF0B66, 0x37D83BF0, 0xA9BCAE53, 0xDEBB9EC5, 0x47B2CF7F, 0x30B5FFE9,
                0xBDBDF21C, 0xCABAC28A, 0x53B39330, 0x24B4A3A6, 0xBAD03605, 0xCDD70693,
                0x54DE5729, 0x23D967BF, 0xB3667A2E, 0xC4614AB8, 0x5D681B02, 0x2A6F2B94,
                0xB40BBE37, 0xC30C8EA1, 0x5A05DF1B, 0x2D02EF8D
        };

            unchecked
            {
                uint crc = (uint)(((uint)0) ^ (-1));
                var len = input.Length;
                for (var i = 0; i < len; i++)
                {
                    crc = (crc >> 8) ^ table[
                        (crc ^ (byte)input[i]) & 0xFF
                ];
                }
                crc = (uint)(crc ^ (-1));

                if (crc < 0)
                {
                    crc += (uint)4294967296;
                }

                return crc;
            }
        }
    }
}