一个穷举密码的类

温故而知新，看了一个C语言利用指针写的穷举密码的函数。正好有几个自己写的简易工具里需要使用到，随写一个C#版本。

    public class PasswordString
{

        private static readonly string _number = "0123456789";
        private static readonly string _uppercase = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
        private static readonly string _lowercase = "abcdefghijklmnopqrstuvwxyz";
        private static string _other;
        #endregion
        public static string Number
{
            get
{
                return _number;
            }
        }

        public static string Uppercase
{
            get
{
                return _uppercase;
            }
        }

        public static string Lowercase
{
            get
{
                return _lowercase;
            }
        }

        public static string Other
{
            get
{
                return _other;
            }
            set
{
                _other = Other;
            }
        }
    }

    public class EnumPassword
{

        private ulong _Counter = 0;
        private string _Source = PasswordString.Number + PasswordString.Lowercase + PasswordString.Uppercase;
        private string _Password = "";
        private ulong _Min = 3;
        private ulong _Max = 8;
        #endregion


        private string _GetPassword(ulong counter)
{
            char [] str = new char[this._Max];
            char [] src = _Source.ToCharArray();
            ulong n = 0;
            ulong len = (ulong)src.Length;
            str[n] = src[counter % len];
            while(counter >= len)
{
                counter /= (ulong)src.Length;
                str[n + 1] = src[counter % len];
                n++;
            }
            this._Password = new string(str).Substring(0, (int)(n + 1));
            return this._Password;
        }
        #endregion
        public EnumPassword()
{
            this._Counter = (ulong)Math.Pow(this._Source.Length, this._Min - 1);
        }
        public EnumPassword(ulong min, ulong max)
{
            if(min > max)
                throw new Exception("Min is smaller than max.");
            this._Min = min;
            this._Max = max;
            this._Counter = (ulong)Math.Pow(this._Source.Length, this._Min - 1);
        }
        public string Password()
{
            return this._Password;
        }
        public string Next()
{
            ulong counter;
            lock(this)
{
                counter = this._Counter;
                this._Counter++;
            }
            string pass = this._GetPassword(counter);
            return pass;
        }

        public string Source
{
            get
{
                return this._Source;
            }
            set
{
                this._Source = Source;
            }
        }    
    }

还有很多功能没有实现，不过那些都是简单玩意了。主要问题是效率不高，主要是string类型的使用实在是太XXX，等过几天，再优化优化~~~~大家有什么建议，帮我看看，提提~~