1 /* 2 * Copyright (c) 2015, 2015, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 */ 23 package org.graalvm.compiler.graph; 24 25 public final class NodeStack { 26 27 private static final int INITIAL_SIZE = 8; 28 29 protected Node[] values; 30 public int tos; 31 32 public NodeStack() { 33 values = new Node[INITIAL_SIZE]; 34 } 35 36 public void push(Node n) { 37 int newIndex = tos++; 38 int valuesLength = values.length; 39 if (newIndex >= valuesLength) { 40 grow(); 41 } 42 values[newIndex] = n; 43 } 44 45 private void grow() { 46 int valuesLength = values.length; 47 Node[] newValues = new Node[valuesLength << 1]; 48 System.arraycopy(values, 0, newValues, 0, valuesLength); 49 values = newValues; 50 } 51 52 public Node pop() { 53 assert tos > 0 : "stack must be non-empty"; 54 return values[--tos]; 55 } 56 57 public Node peek() { 58 assert tos > 0 : "stack must be non-empty"; 59 return values[tos - 1]; 60 } 61 62 public boolean isEmpty() { 63 return tos == 0; 64 } 65 66 @Override 67 public String toString() { 68 if (tos == 0) { 69 return "NodeStack: []"; 70 } 71 StringBuilder sb = new StringBuilder(); 72 for (int i = 0; i < tos; i++) { 73 sb.append(", "); 74 sb.append(values[i]); 75 } 76 return "NodeStack: [" + sb.substring(2) + "]"; 77 } 78 }