iTextSharp.text.pdf.PdfReader.RemoveUnusedNode C# (CSharp) Метод

        protected internal void RemoveUnusedNode(PdfObject obj, bool[] hits) {
            Stack state = new Stack();
            state.Push(obj);
            while (state.Count != 0) {
                Object current = state.Pop();
                if (current == null)
                    continue;
                ArrayList ar = null;
                PdfDictionary dic = null;
                PdfName[] keys = null;
                Object[] objs = null;
                int idx = 0;
                if (current is PdfObject) {
                    obj = (PdfObject)current;
                    switch (obj.Type) {
                        case PdfObject.DICTIONARY:
                        case PdfObject.STREAM:
                            dic = (PdfDictionary)obj;
                            keys = new PdfName[dic.Size];
                            dic.Keys.CopyTo(keys, 0);
                            break;
                        case PdfObject.ARRAY:
                            ar = ((PdfArray)obj).ArrayList;
                            break;
                        case PdfObject.INDIRECT:
                            PRIndirectReference refi = (PRIndirectReference)obj;
                            int num = refi.Number;
                            if (!hits[num]) {
                                hits[num] = true;
                                state.Push(GetPdfObjectRelease(refi));
                            }
                            continue;
                        default:
                            continue;
                    }
                }
                else {
                    objs = (Object[])current;
                    if (objs[0] is ArrayList) {
                        ar = (ArrayList)objs[0];
                        idx = (int)objs[1];
                    }
                    else {
                        keys = (PdfName[])objs[0];
                        dic = (PdfDictionary)objs[1];
                        idx = (int)objs[2];
                    }
                }
                if (ar != null) {
                    for (int k = idx; k < ar.Count; ++k) {
                        PdfObject v = (PdfObject)ar[k];
                        if (v.IsIndirect()) {
                            int num = ((PRIndirectReference)v).Number;
                            if (num >= xrefObj.Count || (!partial && xrefObj[num] == null)) {
                                ar[k] = PdfNull.PDFNULL;
                                continue;
                            }
                        }
                        if (objs == null)
                            state.Push(new Object[]{ar, k + 1});
                        else {
                            objs[1] = k + 1;
                            state.Push(objs);
                        }
                        state.Push(v);
                        break;
                    }
                }
                else {
                    for (int k = idx; k < keys.Length; ++k) {
                        PdfName key = keys[k];
                        PdfObject v = dic.Get(key);
                        if (v.IsIndirect()) {
                            int num = ((PRIndirectReference)v).Number;
                            if (num >= xrefObj.Count || (!partial && xrefObj[num] == null)) {
                                dic.Put(key, PdfNull.PDFNULL);
                                continue;
                            }
                        }
                        if (objs == null)
                            state.Push(new Object[]{keys, dic, k + 1});
                        else {
                            objs[2] = k + 1;
                            state.Push(objs);
                        }
                        state.Push(v);
                        break;
                    }
                }
            }
        }