1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one
3 * or more contributor license agreements. See the NOTICE file
4 * distributed with this work for additional information
5 * regarding copyright ownership. The ASF licenses this file
6 * to you under the Apache License, Version 2.0 (the
7 * "License"); you may not use this file except in compliance
8 * with the License. You may obtain a copy of the License at
9 *
10 * https://www.apache.org/licenses/LICENSE-2.0
11 *
12 * Unless required by applicable law or agreed to in writing,
13 * software distributed under the License is distributed on an
14 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15 * KIND, either express or implied. See the License for the
16 * specific language governing permissions and limitations
17 * under the License.
18 */
19 package org.apache.bcel.generic;
20
21 import java.io.DataOutputStream;
22 import java.io.IOException;
23
24 /**
25 * JSR - Jump to subroutine
26 */
27 public class JSR extends JsrInstruction implements VariableLengthInstruction {
28
29 /**
30 * Empty constructor needed for Instruction.readInstruction. Not to be used otherwise.
31 */
32 JSR() {
33 }
34
35 /**
36 * Constructs a JSR instruction.
37 *
38 * @param target branch target.
39 */
40 public JSR(final InstructionHandle target) {
41 super(org.apache.bcel.Const.JSR, target);
42 }
43
44 /**
45 * Call corresponding visitor method(s). The order is: Call visitor methods of implemented interfaces first, then call
46 * methods according to the class hierarchy in descending order, that is, the most specific visitXXX() call comes last.
47 *
48 * @param v Visitor object.
49 */
50 @Override
51 public void accept(final Visitor v) {
52 v.visitStackProducer(this);
53 v.visitVariableLengthInstruction(this);
54 v.visitBranchInstruction(this);
55 v.visitJsrInstruction(this);
56 v.visitJSR(this);
57 }
58
59 /**
60 * Dumps instruction as byte code to stream out.
61 *
62 * @param out Output stream.
63 */
64 @Override
65 public void dump(final DataOutputStream out) throws IOException {
66 super.setIndex(getTargetOffset());
67 if (super.getOpcode() == org.apache.bcel.Const.JSR) {
68 super.dump(out);
69 } else { // JSR_W
70 super.setIndex(getTargetOffset());
71 out.writeByte(super.getOpcode());
72 out.writeInt(super.getIndex());
73 }
74 }
75
76 @Override
77 protected int updatePosition(final int offset, final int maxOffset) {
78 final int i = getTargetOffset(); // Depending on old position value
79 setPosition(getPosition() + offset); // Position may be shifted by preceding expansions
80 if (Math.abs(i) >= Short.MAX_VALUE - maxOffset) { // to large for short (estimate)
81 super.setOpcode(org.apache.bcel.Const.JSR_W);
82 final short oldLength = (short) super.getLength();
83 super.setLength(5);
84 return super.getLength() - oldLength;
85 }
86 return 0;
87 }
88 }