【摘要】一个字符串解析类

很久以前在CodeProject上看到一个控件源码http://www.codeproject.com/Articles/7247/Themed-Windows-XP-style-Explorer-Bar，里面有一个字符串解析的类，今天翻出来贴到这里。

#region StringTokenizer Class

    /// <summary>
    /// A class that breaks a string into tokens
    /// </summary>
    internal class StringTokenizer
    {
        /// <summary>
        /// The index of the current token
        /// </summary>
        private int currentIndex;

        /// <summary>
        /// The number of tokens
        /// </summary>
        private int numberOfTokens;

        /// <summary>
        /// Internal list of tokens
        /// </summary>
        private ArrayList tokens;

        /// <summary>
        /// The string to be parsed
        /// </summary>
        private string source;

        /// <summary>
        /// The delimiters
        /// </summary>
        private string delimiter;

        /// <summary>
        /// Initializes a new instance of the StringTokenizer class with the
        /// specified source string and delimiters
        /// </summary>
        /// <param name="source">The String to be parsed</param>
        /// <param name="delimiter">A String containing the delimiters</param>
        public StringTokenizer(string source, string delimiter)
        {
            this.tokens = new ArrayList(10);
            this.source = source;
            this.delimiter = delimiter;

            if (delimiter.Length == 0)
            {
                this.delimiter = " ";
            }

            this.Tokenize();
        }

        /// <summary>
        /// Initializes a new instance of the StringTokenizer class with the
        /// specified source string and delimiters
        /// </summary>
        /// <param name="source">The String to be parsed</param>
        /// <param name="delimiter">A char array containing the delimiters</param>
        public StringTokenizer(string source, char[] delimiter)
            : this(source, new string(delimiter))
        {

        }

        /// <summary>
        /// Initializes a new instance of the StringTokenizer class with the
        /// specified source string
        /// </summary>
        /// <param name="source">The String to be parsed</param>
        public StringTokenizer(string source)
            : this(source, "")
        {

        }

        /// <summary>
        /// Parses the source string
        /// </summary>
        private void Tokenize()
        {
            string s = this.source;
            StringBuilder sb = new StringBuilder();
            this.numberOfTokens = 0;
            this.tokens.Clear();
            this.currentIndex = 0;

            int i = 0;

            while (i < this.source.Length)
            {
                if (this.delimiter.IndexOf(this.source[i]) != -1)
                {
                    if (sb.Length > 0)
                    {
                        this.tokens.Add(sb.ToString());

                        sb.Remove(0, sb.Length);
                    }
                }
                else
                {
                    sb.Append(this.source[i]);
                }

                i++;
            }

            this.numberOfTokens = this.tokens.Count;
        }

        /// <summary>
        /// Returns the number of tokens in the string
        /// </summary>
        /// <returns>The number of tokens in the string</returns>
        public int CountTokens()
        {
            return this.tokens.Count;
        }

        /// <summary>
        /// Checks if there are more tokens available from this tokenizer's
        /// string
        /// </summary>
        /// <returns>true if more tokens are available, false otherwise</returns>
        public bool HasMoreTokens()
        {
            if (this.currentIndex <= (this.tokens.Count - 1))
            {
                return true;
            }
            else
            {
                return false;
            }
        }

        /// <summary>
        /// Returns the current token and moves to the next token
        /// </summary>
        /// <returns>The current token</returns>
        public string NextToken()
        {
            string s = "";

            if (this.currentIndex <= (this.tokens.Count - 1))
            {
                s = (string)tokens[this.currentIndex];

                this.currentIndex++;

                return s;
            }
            else
            {
                return null;
            }
        }

        /// <summary>
        /// Moves to the next token without returning the current token
        /// </summary>
        public void SkipToken()
        {
            if (this.currentIndex <= (this.tokens.Count - 1))
            {
                this.currentIndex++;
            }
        }

        /// <summary>
        /// Returns the current token but does not move to the next token
        /// </summary>
        /// <returns></returns>
        public string PeekToken()
        {
            string s = "";

            if (this.currentIndex <= (this.tokens.Count - 1))
            {
                s = (string)tokens[this.currentIndex];

                return s;
            }
            else
            {
                return null;
            }
        }

        /// <summary>
        /// Returns the source string
        /// </summary>
        public string Source
        {
            get
            {
                return this.source;
            }
        }

        /// <summary>
        /// Returns a string that contains the delimiters used to
        /// parse the source string
        /// </summary>
        public string Delimiter
        {
            get
            {
                return this.delimiter;
            }
        }
    }

    #endregion