public PasswordRestriction(
SymbolsType acceptedTypes,
int passwordMinLength = DefaultMinLength,
int passwordMaxLength = DefaultMaxLength)
{
Contract.Assert(passwordMinLength > 0);
Contract.Assert(passwordMaxLength >= passwordMinLength);
Contract.Assert(acceptedTypes.Count() <= passwordMaxLength);
AcceptedTypes = acceptedTypes;
PasswordMaxLength = passwordMaxLength;
PasswordMinLength = passwordMinLength;
}
private static string GenerateRestPart(
SymbolsType acceptedTypes,
byte[] restPartNumbers,
long length)
{
var passwordPartBuilder = new StringBuilder();
var acceptedSymbols = acceptedTypes.GetSymbols();
for (var i = 0; i < length; i++)
{
var symbolNumber = restPartNumbers[i] % acceptedSymbols.Length;
passwordPartBuilder.Append(acceptedSymbols[symbolNumber]);
}
return passwordPartBuilder.ToString();
}
private static string GenerateMandatoryPart(
SymbolsType acceptedTypes,
byte[] passwordSymbolsNumbers)
{
var passwordPartBuilder = new StringBuilder();
for (var i = 0; acceptedTypes != 0; i++)
{
var randomTypeNumber = passwordSymbolsNumbers[2 * i];
var randomSymbolNumber = passwordSymbolsNumbers[2 * i + 1];
var unusedTypes = acceptedTypes.GetFlags().ToArray();
var usedType = unusedTypes[randomTypeNumber % unusedTypes.Length];
var usedSymbols = usedType.GetSymbols();
passwordPartBuilder.Append(usedSymbols[randomSymbolNumber % usedSymbols.Length]);
acceptedTypes = TurnOffFlag(acceptedTypes, usedType);
}
return passwordPartBuilder.ToString();
}
private static SymbolsType TurnOffFlag(SymbolsType flags, SymbolsType flag) => flags & ~flag;
public static IEnumerable <SymbolsType> GetFlags(this SymbolsType input)
{
return(AllTypes().Where(type => input.HasFlag(type)));
}
public static long Count(this SymbolsType type)
{
return(Enumerable.Range(0, 64).Sum(number => ((long)type >> number) & 1));
}