Neural Network for Recognition of Handwritten Digits in C#

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

namespace ArchiveSerialization
{
	static public class MFCStringReader
	{
		static public string ReadCString(BinaryReader reader)
		{
			string str = "";
			int nConvert = 1; // if we get ANSI, convert

			UInt32 nNewLen = ReadStringLength(reader);
			if (nNewLen == unchecked((UInt32)(-1)))
			{
				nConvert = 1 - nConvert;
				nNewLen = ReadStringLength(reader);
				if (nNewLen == unchecked((UInt32)(-1)))
					return str;
			}

			// set length of string to new length
			UInt32 nByteLen = nNewLen;
			nByteLen += (UInt32)(nByteLen * (1 - nConvert)); // bytes to read

			// read in the characters
			if (nNewLen != 0)
			{
				// read new data
				byte[] byteBuf = reader.ReadBytes((int)nByteLen);

				// convert the data if as necessary
				StringBuilder sb = new StringBuilder();
				if (nConvert != 0)
				{
					for (int i = 0; i < nNewLen; i++)
						sb.Append((char)byteBuf[i]);
				}
				else
				{
					for (int i = 0; i < nNewLen; i++)
						sb.Append((char)(byteBuf[i * 2] + byteBuf[i * 2 + 1] * 256));
				}

				str = sb.ToString();
			}

			return str;
		}

		static private UInt32 ReadStringLength(BinaryReader reader)
		{
			UInt32 nNewLen;

			// attempt BYTE length first
			byte bLen = reader.ReadByte();

			if (bLen < 0xff)
				return bLen;

			// attempt WORD length
			UInt16 wLen = reader.ReadUInt16();
			if (wLen == 0xfffe)
			{
				// UNICODE string prefix (length will follow)
				return unchecked((UInt32)(-1));
			}
			else if (wLen == 0xffff)
			{
				// read DWORD of length
				nNewLen = reader.ReadUInt32();
				return nNewLen;
			}
			else
				return wLen;
		}
	}
}