Gameloft's OBB Repacker 0.1

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

class Program
{
    static void Main(string[] args)
    {
        String Arg = args[0];
        if (File.Exists(Arg))
        {
            Console.WriteLine("Loading file index");
            Regex regexObj = new Regex(@"^(?<START>\d+) (?<END>\d+) \d+ \d+ (?<PATH>(\s|\S)+)$", RegexOptions.IgnoreCase | RegexOptions.Multiline);
            Byte[] Data = File.ReadAllBytes(Arg);
            Int32 IndexOffset = Int32.Parse(((Char)Data[0]).ToString() + (Char)Data[1] + (Char)Data[2] + (Char)Data[3] + (Char)Data[4] + (Char)Data[5] + (Char)Data[6] + (Char)Data[7] + (Char)Data[8]);
            String RawRow = "";
            for (int i = IndexOffset; i < Data.Length; i++)
            {
                if (Data[i] == 0x0A)
                {
                    Match Row = regexObj.Match(RawRow);
                    String Path = AppDomain.CurrentDomain.BaseDirectory + "Root\\" + Row.Groups["PATH"].Value;
                    Int32 StartOffset = Int32.Parse(Row.Groups["START"].Value);
                    Int32 EndOffset = Int32.Parse(Row.Groups["END"].Value);
                    Int32 OffsetLength = EndOffset - StartOffset;
                    Console.WriteLine("Extracting ./Root/" + Row.Groups["PATH"].Value);
                    Directory.CreateDirectory(Path);
                    Directory.Delete(Path);
                    FileStream FStream = File.OpenWrite(Path);
                    FStream.Write(Data, StartOffset, OffsetLength);
                    FStream.Close();
                    RawRow = "";
                }
                else
                    RawRow += (char)Data[i];
            }
        }
        else if (Directory.Exists(Arg))
        {
            Console.WriteLine("Repacking");
            FileStream FStream = File.OpenWrite(AppDomain.CurrentDomain.BaseDirectory + "main.1050.com.gameloft.android.ANMP.GloftPOHM.obb");
            for (int i = 0; i < 9; i++)
                FStream.WriteByte(0);
            String Index = "";
            Int32 Offset = 9;
            foreach (String FullPath in Directory.GetFiles(Arg, "*", SearchOption.AllDirectories))
            {
                String Path = FullPath.Remove(0, Arg.Length + 1).Replace("\\", "/");
                Int32 StartOffset = Offset;
                Int32 OffsetLength = (Int32)(new FileInfo(FullPath)).Length;
                Int32 EndOffset = Offset + OffsetLength;
                Offset += OffsetLength;
                Index += String.Format("{0} {1} {2} {3} {4}\n", StartOffset, EndOffset, "0", StartOffset, Path);
                FStream.Write(File.ReadAllBytes(FullPath), 0, OffsetLength);
            }
            FStream.Write(Encoding.ASCII.GetBytes(Index), 0, Index.Length - 1);
            FStream.Seek(0, SeekOrigin.Begin);
            FStream.Write((Encoding.ASCII.GetBytes(Offset.ToString("000000000"))), 0, 9);
            FStream.Close();
        }
    }
}