using System;
using System.Text;

namespace CPF.ReoGrid.Formula
{
	internal class ReplacableString
	{
		internal ReplacableString(string str)
		{
			this.original = str;
			this.Restore();
		}

		internal int Offset
		{
			get
			{
				return this.offset;
			}
		}

		public int Replace(int from, int len, string newstr)
		{
			this.sb.Remove(from, len);
			this.sb.Insert(from, newstr);
			int num = newstr.Length - len;
			this.offset += num;
			return num;
		}

		public override string ToString()
		{
			return this.sb.ToString();
		}

		public void Restore()
		{
			bool flag = this.sb == null;
			if (flag)
			{
				this.sb = new StringBuilder(this.original, 256);
			}
			else
			{
				this.sb.Length = 0;
				this.sb.Append(this.original);
			}
			this.offset = 0;
		}

		private string original;

		private StringBuilder sb;

		private int offset = 0;
	}
}