Nintendo Zone hotspot.conf Decoder

hotspot_conf_decoder.cs

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

namespace hotspot_conf_decoder
{
	class Program
	{
		static void Main(string[] args)
		{
			var hotspotConfPath = @"C:\Programs\3DSHackingToolkit\PackHack\ExtractedRomFS\hotspot.conf";
			if (args.Length > 0 && !string.IsNullOrEmpty(args[0]))
				hotspotConfPath = args[0];
			using (var reader = File.OpenText(hotspotConfPath))
			{
				var interval = reader.ReadLine();
				var intervalVal = reader.ReadLine();
				var header = reader.ReadLine();
				var configs = new List<List<string>>();
				do
				{
					var line = reader.ReadLine();
					var lineValues = DecodeCsvLine(line);
					for (var i = 0; i < 4; i++)
						lineValues[i] = DecodeBase64(lineValues[i]);
					configs.Add(lineValues);
				} while (!reader.EndOfStream);

				var resultPath = Path.Combine(Path.GetDirectoryName(hotspotConfPath), "hotspot_decoded.conf");
				using (var stream = File.Open(resultPath, FileMode.Create, FileAccess.Write, FileShare.Read))
				using (var writer = new StreamWriter(stream))
				{
					writer.WriteLine(interval);
					writer.WriteLine(intervalVal);
					writer.WriteLine(header);
					foreach (var line in configs)
						writer.WriteLine(string.Join(",", line));
				}
			}

		}

		private static List<string> DecodeCsvLine(string input)
		{
			var result = new List<string>();
			var buf = new StringBuilder();
			foreach (var c in input)
			{
				switch (c)
				{
					case ',':
						result.Add(buf.ToString());
						buf.Clear();
						break;
					default:
						buf.Append(c);
						break;
				}
			}
			result.Add(buf.ToString());
			return result;
		}

		private static string DecodeBase64(string str)
		{
			if (string.IsNullOrEmpty(str))
				return str;

			var validBase64 = str.Replace('*', '=').Replace('.', '+').Replace('-', '/');
			var bytes = Convert.FromBase64String(validBase64);

			string result;
			var isBinary = bytes.Last() == 0x00;
			if (isBinary)
			{
				Array.Resize(ref bytes, bytes.Length-1);
				var buf = new StringBuilder(bytes.Length*2);
				foreach (var b in bytes)
					buf.Append(b.ToString("x2"));
				result = buf.ToString();
			}
			else
				result = Encoding.UTF8.GetString(bytes);
			return result;
		}
	}
}