System.IO.Compression.FastEncoderWindow.MoveWindows C# (CSharp) Method

        public void MoveWindows() {
            int num;
            Array.Copy(this.window, this.bufPos - 0x2000, this.window, 0, 0x2000);
            for (num = 0; num < 0x800; num++) {
                int num2 = this.lookup[num] - 0x2000;
                if (num2 <= 0) {
                    this.lookup[num] = 0;
                }
                else {
                    this.lookup[num] = (ushort)num2;
                }
            }
            for (num = 0; num < 0x2000; num++) {
                long num3 = this.prev[num] - 0x2000L;
                if (num3 <= 0L) {
                    this.prev[num] = 0;
                }
                else {
                    this.prev[num] = (ushort)num3;
                }
            }
            this.bufPos = 0x2000;
            this.bufEnd = this.bufPos;
        }