1 /* 2 * Copyright (c) 2009, 2011, 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.bytecode; 24 25 /** 26 * A utility for processing {@link Bytecodes#TABLESWITCH} bytecodes. 27 */ 28 public class BytecodeTableSwitch extends BytecodeSwitch { 29 30 private static final int OFFSET_TO_LOW_KEY = 4; 31 private static final int OFFSET_TO_HIGH_KEY = 8; 32 private static final int OFFSET_TO_FIRST_JUMP_OFFSET = 12; 33 private static final int JUMP_OFFSET_SIZE = 4; 34 35 /** 36 * Constructor for a {@link BytecodeStream}. 37 * 38 * @param stream the {@code BytecodeStream} containing the switch instruction 39 * @param bci the index in the stream of the switch instruction 40 */ 41 public BytecodeTableSwitch(BytecodeStream stream, int bci) { 42 super(stream, bci); 43 } 44 45 /** 46 * Gets the low key of the table switch. 47 * 48 * @return the low key 49 */ 50 public int lowKey() { 51 return stream.readInt(alignedBci + OFFSET_TO_LOW_KEY); 52 } 53 54 /** 55 * Gets the high key of the table switch. 56 * 57 * @return the high key 58 */ 59 public int highKey() { 60 return stream.readInt(alignedBci + OFFSET_TO_HIGH_KEY); 61 } 62 63 @Override 64 public int keyAt(int i) { 65 return lowKey() + i; 66 } 67 68 @Override 69 public int offsetAt(int i) { 70 return stream.readInt(alignedBci + OFFSET_TO_FIRST_JUMP_OFFSET + JUMP_OFFSET_SIZE * i); 71 } 72 73 @Override 74 public int numberOfCases() { 75 return highKey() - lowKey() + 1; 76 } 77 78 @Override 79 public int size() { 80 return alignedBci + OFFSET_TO_FIRST_JUMP_OFFSET + JUMP_OFFSET_SIZE * numberOfCases() - bci; 81 } 82 }