1/*
2 * Javassist, a Java-bytecode translator toolkit.
3 * Copyright (C) 1999-2007 Shigeru Chiba, and others. All Rights Reserved.
4 *
5 * The contents of this file are subject to the Mozilla Public License Version
6 * 1.1 (the "License"); you may not use this file except in compliance with
7 * the License.  Alternatively, the contents of this file may be used under
8 * the terms of the GNU Lesser General Public License Version 2.1 or later.
9 *
10 * Software distributed under the License is distributed on an "AS IS" basis,
11 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
12 * for the specific language governing rights and limitations under the
13 * License.
14 */
15package javassist.bytecode.analysis;
16
17import javassist.bytecode.CodeIterator;
18import javassist.bytecode.Opcode;
19
20/**
21 * A set of common utility methods.
22 *
23 * @author Jason T. Greene
24 */
25public class Util implements Opcode {
26    public static int getJumpTarget(int pos, CodeIterator iter) {
27        int opcode = iter.byteAt(pos);
28        pos += (opcode == JSR_W || opcode == GOTO_W) ? iter.s32bitAt(pos + 1) : iter.s16bitAt(pos + 1);
29        return pos;
30    }
31
32    public static boolean isJumpInstruction(int opcode) {
33        return (opcode >= IFEQ && opcode <= JSR) || opcode == IFNULL || opcode == IFNONNULL || opcode == JSR_W || opcode == GOTO_W;
34    }
35
36    public static boolean isGoto(int opcode) {
37        return opcode == GOTO || opcode == GOTO_W;
38    }
39
40    public static boolean isJsr(int opcode) {
41        return opcode == JSR || opcode == JSR_W;
42    }
43
44    public static boolean isReturn(int opcode) {
45        return (opcode >= IRETURN && opcode <= RETURN);
46    }
47}
48