public static EnigmaMachine Load(Stream stream)
{
using var reader = new BinaryReader(stream);
//HEADER
var buffer = reader.ReadString();
if (buffer != "EGMC")
{
throw new FormatException("Not a valid Enigma Machine File");
}
//ALPHABET
buffer = reader.ReadString();
if (buffer != "alph")
{
throw new FormatException("Not a valid Enigma Machine File");
}
var len = reader.ReadInt32();
buffer = reader.ReadString();
var alphabet = new Alphabet(buffer);
//AUTORESET
var autroreset = reader.ReadBoolean();
//STATOR AND REFLECTOR
var list = new string[] { "ETW ", "UKW " };
var wheels = new List <EnigmaWheel>(2);
foreach (var item in list)
{
buffer = reader.ReadString();
if (buffer != item)
{
throw new FormatException("Not a valid Enigma Machine File");
}
buffer = reader.ReadString();
if (buffer != "indx")
{
throw new FormatException("Not a valid Enigma Machine File");
}
len = reader.ReadInt32();
buffer = reader.ReadString();
var indexing = new Alphabet(buffer);
buffer = reader.ReadString();
if (buffer != "wire")
{
throw new FormatException("Invalid/Corrupted Enigma File");
}
len = reader.ReadInt32();
buffer = reader.ReadString();
var wiring = new Alphabet(buffer);
var wheel = new EnigmaWheel(indexing, wiring);
wheels.Add(wheel);
}
//ROTORS
buffer = reader.ReadString();
if (buffer != "ROTS")
{
throw new FormatException("Invalid/Corrupted Enigma File");
}
len = reader.ReadInt32();
var builder = new StringBuilder();
var rotors = new List <Rotor>();
while (true)
{
builder.Clear();
buffer = reader.ReadString();
if (buffer != "indx")
{
throw new FormatException("Invalid/Corrupted Enigma File");
}
len = reader.ReadInt32();
buffer = reader.ReadString();
var indexing = new Alphabet(buffer);
buffer = reader.ReadString();
if (buffer != "wire")
{
throw new FormatException("Invalid/Corrupted Enigma File");
}
len = reader.ReadInt32();
buffer = reader.ReadString();
var wiring = new Alphabet(buffer);
var wheel = new EnigmaWheel(indexing, wiring);
buffer = reader.ReadString();
if (buffer != "ntch")
{
throw new FormatException("Invalid/Corrupted Enigma File");
}
len = reader.ReadInt32();
for (int t = 0; t < len; t++)
{
builder.Append(reader.ReadChar());
}
var rotor = new Rotor(indexing, wiring, builder.ToString());
rotors.Add(rotor);
if (reader.PeekChar() == -1)
{
break;
}
}
//BUILDER
return(new EnigmaMachineBuilder()
.WithAlphabet(alphabet)
.WithRotors(rotors)
.WithStator(wheels[0])
.WithReflector(wheels[1])
.Build());
}
/// <summary>
/// When provided, the machine will use the stator and not create its own.
/// If not provided, a default stator is created from the alphabet.
/// </summary>
/// <param name="stator"></param>
/// <returns></returns>
public EnigmaMachineBuilder WithStator(EnigmaWheel stator)
{
_stator = stator;
return(this);
}
/// <summary>
/// When provided, the machine will use the reflector and not create it's own.
/// If not provided, a random reflector is created from the alphabet.
/// </summary>
/// <param name="reflector"></param>
/// <returns></returns>
public EnigmaMachineBuilder WithReflector(EnigmaWheel reflector)
{
_reflector = reflector;
return(this);
}
/// <summary>
/// Builds an <see cref="EnigmaMachine"/> with the provided parameters.
/// </summary>
/// <returns></returns>
public EnigmaMachine Build()
{
var shuffle = new Alphabet(_alphabet.ToString());
//the stator:
var stator = _stator;
if (stator == null)
{
stator = new EnigmaWheel(_alphabet.ToString(), _alphabet.ToString());
}
//the reflector
var reflector = _reflector;
if (reflector == null)
{
shuffle.Shuffle();
reflector = new EnigmaWheel(_alphabet.ToString(), shuffle.ToString());
reflector.Reflect();
}
//the rotors
List <Rotor> rotors;
if (_rotors == null)
{
rotors = new List <Rotor>();
for (int i = 0; i < _rotorCount; i++)
{
string notches = "";
for (int n = 0; n < _notchCount; n++)
{
char c;
do
{
int rnd = Horus.Random(0, _alphabet.Count);
c = _alphabet[rnd];
} while (notches.Contains(c));
notches += c;
}
shuffle.Shuffle();
var rotor = new Rotor(_alphabet.ToString(), shuffle.ToString(), notches);
rotors.Add(rotor);
}
}
else
{
rotors = new List <Rotor>(_rotors);
}
//the actual construction
return(new EnigmaMachine(rotors)
{
Alphabet = _alphabet,
AutoReset = _autoReset,
Stator = stator,
Reflector = reflector,
});
}
