Fan.Sys.FanStr.compareIgnoreCase C# (CSharp) Method

        public static long compareIgnoreCase(string a, string b)
        {
            if (a == b) return 0;

              int an   = a.Length;
              int bn   = b.Length;

              for (int i=0; i<an && i<bn; i++)
              {
            int ac = a[i];
            int bc = b[i];
            if ('A' <= ac && ac <= 'Z') ac |= 0x20;
            if ('A' <= bc && bc <= 'Z') bc |= 0x20;
            if (ac != bc) return ac < bc ? -1 : +1;
              }

              if (an == bn) return 0;
              return an < bn ? -1 : +1;
        }