001/*
002 * Copyright (c) 2009, 2011, Oracle and/or its affiliates. All rights reserved.
003 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
004 *
005 * This code is free software; you can redistribute it and/or modify it
006 * under the terms of the GNU General Public License version 2 only, as
007 * published by the Free Software Foundation.
008 *
009 * This code is distributed in the hope that it will be useful, but WITHOUT
010 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
011 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
012 * version 2 for more details (a copy is included in the LICENSE file that
013 * accompanied this code).
014 *
015 * You should have received a copy of the GNU General Public License version
016 * 2 along with this work; if not, write to the Free Software Foundation,
017 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
018 *
019 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
020 * or visit www.oracle.com if you need additional information or have any
021 * questions.
022 */
023package com.oracle.graal.bytecode;
024
025/**
026 * A utility for processing {@link Bytecodes#TABLESWITCH} bytecodes.
027 */
028public class BytecodeTableSwitch extends BytecodeSwitch {
029
030    private static final int OFFSET_TO_LOW_KEY = 4;
031    private static final int OFFSET_TO_HIGH_KEY = 8;
032    private static final int OFFSET_TO_FIRST_JUMP_OFFSET = 12;
033    private static final int JUMP_OFFSET_SIZE = 4;
034
035    /**
036     * Constructor for a {@link BytecodeStream}.
037     *
038     * @param stream the {@code BytecodeStream} containing the switch instruction
039     * @param bci the index in the stream of the switch instruction
040     */
041    public BytecodeTableSwitch(BytecodeStream stream, int bci) {
042        super(stream, bci);
043    }
044
045    /**
046     * Gets the low key of the table switch.
047     *
048     * @return the low key
049     */
050    public int lowKey() {
051        return stream.readInt(alignedBci + OFFSET_TO_LOW_KEY);
052    }
053
054    /**
055     * Gets the high key of the table switch.
056     *
057     * @return the high key
058     */
059    public int highKey() {
060        return stream.readInt(alignedBci + OFFSET_TO_HIGH_KEY);
061    }
062
063    @Override
064    public int keyAt(int i) {
065        return lowKey() + i;
066    }
067
068    @Override
069    public int offsetAt(int i) {
070        return stream.readInt(alignedBci + OFFSET_TO_FIRST_JUMP_OFFSET + JUMP_OFFSET_SIZE * i);
071    }
072
073    @Override
074    public int numberOfCases() {
075        return highKey() - lowKey() + 1;
076    }
077
078    @Override
079    public int size() {
080        return alignedBci + OFFSET_TO_FIRST_JUMP_OFFSET + JUMP_OFFSET_SIZE * numberOfCases() - bci;
081    }
082}