| /* |
| * Copyright (c) 2017, Oracle and/or its affiliates. All rights reserved. |
| */ |
| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You under the Apache License, Version 2.0 |
| * (the "License"); you may not use this file except in compliance with |
| * the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| package com.sun.org.apache.bcel.internal.generic; |
| |
| import java.io.DataOutputStream; |
| import java.io.IOException; |
| |
| import com.sun.org.apache.bcel.internal.util.ByteSequence; |
| |
| /** |
| * Select - Abstract super class for LOOKUPSWITCH and TABLESWITCH instructions. |
| * |
| * <p> |
| * We use our super's <code>target</code> property as the default target. |
| * |
| * @version $Id: Select.java 1749603 2016-06-21 20:50:19Z ggregory $ |
| * @see LOOKUPSWITCH |
| * @see TABLESWITCH |
| * @see InstructionList |
| */ |
| public abstract class Select extends BranchInstruction implements VariableLengthInstruction, |
| StackConsumer /* @since 6.0 */, StackProducer { |
| |
| private int[] match; // matches, i.e., case 1: ... TODO could be package-protected? |
| private int[] indices; // target offsets TODO could be package-protected? |
| private InstructionHandle[] targets; // target objects in instruction list TODO could be package-protected? |
| private int fixed_length; // fixed length defined by subclasses TODO could be package-protected? |
| private int match_length; // number of cases TODO could be package-protected? |
| private int padding = 0; // number of pad bytes for alignment TODO could be package-protected? |
| |
| /** |
| * Empty constructor needed for the Class.newInstance() statement in |
| * Instruction.readInstruction(). Not to be used otherwise. |
| */ |
| Select() { |
| } |
| |
| /** |
| * (Match, target) pairs for switch. `Match' and `targets' must have the |
| * same length of course. |
| * |
| * @param match array of matching values |
| * @param targets instruction targets |
| * @param defaultTarget default instruction target |
| */ |
| Select(final short opcode, final int[] match, final InstructionHandle[] targets, final InstructionHandle defaultTarget) { |
| // don't set default target before instuction is built |
| super(opcode, null); |
| this.match = match; |
| this.targets = targets; |
| // now it's safe to set default target |
| setTarget(defaultTarget); |
| for (final InstructionHandle target2 : targets) { |
| notifyTarget(null, target2, this); |
| } |
| if ((match_length = match.length) != targets.length) { |
| throw new ClassGenException("Match and target array have not the same length: Match length: " |
| + match.length + " Target length: " + targets.length); |
| } |
| indices = new int[match_length]; |
| } |
| |
| /** |
| * Since this is a variable length instruction, it may shift the following |
| * instructions which then need to update their position. |
| * |
| * Called by InstructionList.setPositions when setting the position for |
| * every instruction. In the presence of variable length instructions |
| * `setPositions' performs multiple passes over the instruction list to |
| * calculate the correct (byte) positions and offsets by calling this |
| * function. |
| * |
| * @param offset additional offset caused by preceding (variable length) |
| * instructions |
| * @param max_offset the maximum offset that may be caused by these |
| * instructions |
| * @return additional offset caused by possible change of this instruction's |
| * length |
| */ |
| @Override |
| protected int updatePosition(final int offset, final int max_offset) { |
| setPosition(getPosition() + offset); // Additional offset caused by preceding SWITCHs, GOTOs, etc. |
| final short old_length = (short) super.getLength(); |
| /* Alignment on 4-byte-boundary, + 1, because of tag byte. |
| */ |
| padding = (4 - ((getPosition() + 1) % 4)) % 4; |
| super.setLength((short) (fixed_length + padding)); // Update length |
| return super.getLength() - old_length; |
| } |
| |
| /** |
| * Dump instruction as byte code to stream out. |
| * |
| * @param out Output stream |
| */ |
| @Override |
| public void dump(final DataOutputStream out) throws IOException { |
| out.writeByte(super.getOpcode()); |
| for (int i = 0; i < padding; i++) { |
| out.writeByte(0); |
| } |
| super.setIndex(getTargetOffset()); // Write default target offset |
| out.writeInt(super.getIndex()); |
| } |
| |
| /** |
| * Read needed data (e.g. index) from file. |
| */ |
| @Override |
| protected void initFromFile(final ByteSequence bytes, final boolean wide) throws IOException { |
| padding = (4 - (bytes.getIndex() % 4)) % 4; // Compute number of pad bytes |
| for (int i = 0; i < padding; i++) { |
| bytes.readByte(); |
| } |
| // Default branch target common for both cases (TABLESWITCH, LOOKUPSWITCH) |
| super.setIndex(bytes.readInt()); |
| } |
| |
| /** |
| * @return mnemonic for instruction |
| */ |
| @Override |
| public String toString(final boolean verbose) { |
| final StringBuilder buf = new StringBuilder(super.toString(verbose)); |
| if (verbose) { |
| for (int i = 0; i < match_length; i++) { |
| String s = "null"; |
| if (targets[i] != null) { |
| s = targets[i].getInstruction().toString(); |
| } |
| buf.append("(").append(match[i]).append(", ").append(s).append(" = {").append( |
| indices[i]).append("})"); |
| } |
| } else { |
| buf.append(" ..."); |
| } |
| return buf.toString(); |
| } |
| |
| /** |
| * Set branch target for `i'th case |
| */ |
| public void setTarget(final int i, final InstructionHandle target) { // TODO could be package-protected? |
| notifyTarget(targets[i], target, this); |
| targets[i] = target; |
| } |
| |
| /** |
| * @param old_ih old target |
| * @param new_ih new target |
| */ |
| @Override |
| public void updateTarget(final InstructionHandle old_ih, final InstructionHandle new_ih) { |
| boolean targeted = false; |
| if (super.getTarget() == old_ih) { |
| targeted = true; |
| setTarget(new_ih); |
| } |
| for (int i = 0; i < targets.length; i++) { |
| if (targets[i] == old_ih) { |
| targeted = true; |
| setTarget(i, new_ih); |
| } |
| } |
| if (!targeted) { |
| throw new ClassGenException("Not targeting " + old_ih); |
| } |
| } |
| |
| /** |
| * @return true, if ih is target of this instruction |
| */ |
| @Override |
| public boolean containsTarget(final InstructionHandle ih) { |
| if (super.getTarget() == ih) { |
| return true; |
| } |
| for (final InstructionHandle target2 : targets) { |
| if (target2 == ih) { |
| return true; |
| } |
| } |
| return false; |
| } |
| |
| @Override |
| protected Object clone() throws CloneNotSupportedException { |
| final Select copy = (Select) super.clone(); |
| copy.match = match.clone(); |
| copy.indices = indices.clone(); |
| copy.targets = targets.clone(); |
| return copy; |
| } |
| |
| /** |
| * Inform targets that they're not targeted anymore. |
| */ |
| @Override |
| void dispose() { |
| super.dispose(); |
| for (final InstructionHandle target2 : targets) { |
| target2.removeTargeter(this); |
| } |
| } |
| |
| /** |
| * @return array of match indices |
| */ |
| public int[] getMatchs() { |
| return match; |
| } |
| |
| /** |
| * @return array of match target offsets |
| */ |
| public int[] getIndices() { |
| return indices; |
| } |
| |
| /** |
| * @return array of match targets |
| */ |
| public InstructionHandle[] getTargets() { |
| return targets; |
| } |
| |
| /** |
| * @return match entry |
| * @since 6.0 |
| */ |
| final int getMatch(final int index) { |
| return match[index]; |
| } |
| |
| /** |
| * @return index entry from indices |
| * @since 6.0 |
| */ |
| final int getIndices(final int index) { |
| return indices[index]; |
| } |
| |
| /** |
| * @return target entry |
| * @since 6.0 |
| */ |
| final InstructionHandle getTarget(final int index) { |
| return targets[index]; |
| } |
| |
| /** |
| * @return the fixed_length |
| * @since 6.0 |
| */ |
| final int getFixed_length() { |
| return fixed_length; |
| } |
| |
| /** |
| * @param fixed_length the fixed_length to set |
| * @since 6.0 |
| */ |
| final void setFixed_length(final int fixed_length) { |
| this.fixed_length = fixed_length; |
| } |
| |
| /** |
| * @return the match_length |
| * @since 6.0 |
| */ |
| final int getMatch_length() { |
| return match_length; |
| } |
| |
| /** |
| * @param match_length the match_length to set |
| * @since 6.0 |
| */ |
| final int setMatch_length(final int match_length) { |
| this.match_length = match_length; |
| return match_length; |
| } |
| |
| /** |
| * |
| * @param index |
| * @param value |
| * @since 6.0 |
| */ |
| final void setMatch(final int index, final int value) { |
| match[index] = value; |
| } |
| |
| /** |
| * |
| * @param array |
| * @since 6.0 |
| */ |
| final void setIndices(final int[] array) { |
| indices = array; |
| } |
| |
| /** |
| * |
| * @param array |
| * @since 6.0 |
| */ |
| final void setMatches(final int[] array) { |
| match = array; |
| } |
| |
| /** |
| * |
| * @param array |
| * @since 6.0 |
| */ |
| final void setTargets(final InstructionHandle[] array) { |
| targets = array; |
| } |
| |
| /** |
| * |
| * @return the padding |
| * @since 6.0 |
| */ |
| final int getPadding() { |
| return padding; |
| } |
| |
| /** |
| * @since 6.0 |
| */ |
| final int setIndices(final int i, final int value) { |
| indices[i] = value; |
| return value; // Allow use in nested calls |
| } |
| } |