using System;
using System.Collections;
using System.Data.SqlTypes;
using Microsoft.SqlServer.Server;

public class CLR_iter
{

    private class stringiter : IEnumerator
    {
        string  _str;
        char    delim;
        int     _start_ix;
        int     _end_ix;
        int     _listpos;

         public string str {
           get {
              return this._str;
           }
        }

        public int start_ix {
           get {
              return this._start_ix;
           }
        }

        public int end_ix {
           get {
              return this._end_ix;
           }
        }

        public int listpos {
           get {
              return this._listpos;
           }
        }

        public stringiter(SqlString  str,
                          SqlString  delimiter) {
           this._str  = str.IsNull ? "" : str.Value;
           this.delim = delimiter.IsNull ? '\0'
                                         : delimiter.Value.ToCharArray(0, 1)[0];
           Reset();
        }

        public bool MoveNext() {
            this._start_ix = this._end_ix + 1;
            if (delim == ' ') {
               while (this._start_ix < this._str.Length &&
                      this.str[this._start_ix] == ' ') {
                  this._start_ix++;
               }
            }

            if (this._start_ix >= this._str.Length) {
               return false;
            }

            this._end_ix = this.str.IndexOf(this.delim, this._start_ix);
            this._listpos++;
            if (this.end_ix == -1) {
               this._end_ix = this._str.Length;
            }
            return true;
        }

        public Object Current {
          get {
            return this;
          }
        }

        public void Reset() {
           this._start_ix = -1;
           this._end_ix   = -1;
           this._listpos  = 0;
        }
    }

    [SqlFunction(FillRowMethodName="CharlistFillRow")]
    public static IEnumerator CLR_charlist_iter(SqlString str,
                                                SqlString delimiter)
    {
        return new stringiter(str, delimiter);
    }

    public static void CharlistFillRow(object     obj,
                                       out int    listpos,
                                       out string str)
    {
        stringiter iter = (stringiter) obj;
        listpos = iter.listpos;
        str = iter.str.Substring(iter.start_ix, iter.end_ix - iter.start_ix);
        str = str.Trim();
    }


    [SqlFunction(FillRowMethodName="IntlistFillRow")]
    public static IEnumerator CLR_intlist_iter(SqlString str,
                                               SqlString delimiter)
    {
        return new stringiter(str, delimiter);
    }

    public static void IntlistFillRow(object     obj,
                                      out int    listpos,
                                      out int    number)
    {
        stringiter iter = (stringiter) obj;
        listpos = iter.listpos;
        string str = iter.str.Substring(iter.start_ix, iter.end_ix - iter.start_ix);
        number = System.Convert.ToInt32(str);
    }
}