System.Security.Util.StringExpressionSet.AddSingleExpressionNoDuplicates C# (CSharp) Method

        protected void AddSingleExpressionNoDuplicates( String expression )
        {
            int index = 0;
            
            m_expressionsArray = null;
            m_expressions = null;

            if (this.m_list == null)
                this.m_list = new ArrayList();

            while (index < this.m_list.Count)
            {
                if (StringSubsetString( (String)this.m_list[index], expression, m_ignoreCase ))
                {
                    this.m_list.RemoveAt( index );
                }
                else if (StringSubsetString( expression, (String)this.m_list[index], m_ignoreCase ))
                {
                    return;
                }
                else
                {
                    index++;
                }
            }
            this.m_list.Add( expression );
        }
    

        public StringExpressionSet Intersect(StringExpressionSet ses)
        {
            if (this.IsEmpty() || ses == null || ses.IsEmpty())
            {
                return(this.CreateNewEmpty());
            }
            this.CheckList();
            ses.CheckList();
            StringExpressionSet stringExpressionSet = this.CreateNewEmpty();

            for (int i = 0; i < this.m_list.Count; i++)
            {
                for (int j = 0; j < ses.m_list.Count; j++)
                {
                    if (this.StringSubsetString((string)this.m_list[i], (string)ses.m_list[j], this.m_ignoreCase))
                    {
                        if (stringExpressionSet.m_list == null)
                        {
                            stringExpressionSet.m_list = new ArrayList();
                        }
                        stringExpressionSet.AddSingleExpressionNoDuplicates((string)this.m_list[i]);
                    }
                    else if (this.StringSubsetString((string)ses.m_list[j], (string)this.m_list[i], this.m_ignoreCase))
                    {
                        if (stringExpressionSet.m_list == null)
                        {
                            stringExpressionSet.m_list = new ArrayList();
                        }
                        stringExpressionSet.AddSingleExpressionNoDuplicates((string)ses.m_list[j]);
                    }
                }
            }
            stringExpressionSet.GenerateString();
            return(stringExpressionSet);
        }