/*
* ProGuard -- shrinking, optimization, obfuscation, and preverification
* of Java bytecode.
*
* Copyright (c) 2002-2010 Eric Lafortune (eric@graphics.cornell.edu)
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the Free
* Software Foundation; either version 2 of the License, or (at your option)
* any later version.
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
package proguard.optimize.peephole;
import proguard.classfile.constant.Constant;
import proguard.classfile.editor.CodeAttributeEditor;
import proguard.classfile.instruction.Instruction;
import proguard.classfile.instruction.visitor.*;
/**
* This InstructionVisitor replaces multiple instruction sequences at once.
*
* @see InstructionSequenceReplacer
* @author Eric Lafortune
*/
public class InstructionSequencesReplacer
extends MultiInstructionVisitor
implements InstructionVisitor
{
private static final int PATTERN_INDEX = 0;
private static final int REPLACEMENT_INDEX = 1;
/**
* Creates a new InstructionSequencesReplacer.
* @param patternConstants any constants referenced by the pattern
* instruction.
* @param instructionSequences the instruction sequences to be replaced,
* with subsequently the sequence pair index,
* the patten/replacement index (0 or 1),
* and the instruction index in the sequence.
* @param branchTargetFinder a branch target finder that has been
* initialized to indicate branch targets
* in the visited code.
* @param codeAttributeEditor a code editor that can be used for
* accumulating changes to the code.
*/
public InstructionSequencesReplacer(Constant[] patternConstants,
Instruction[][][] instructionSequences,
BranchTargetFinder branchTargetFinder,
CodeAttributeEditor codeAttributeEditor)
{
this(patternConstants,
instructionSequences,
branchTargetFinder,
codeAttributeEditor,
null);
}
/**
* Creates a new InstructionSequenceReplacer.
* @param patternConstants any constants referenced by the pattern
* instruction.
* @param instructionSequences the instruction sequences to be replaced,
* with subsequently the sequence pair index,
* the patten/replacement index (0 or 1),
* and the instruction index in the sequence.
* @param branchTargetFinder a branch target finder that has been
* initialized to indicate branch targets
* in the visited code.
* @param codeAttributeEditor a code editor that can be used for
* accumulating changes to the code.
* @param extraInstructionVisitor an optional extra visitor for all deleted
* load instructions.
*/
public InstructionSequencesReplacer(Constant[] patternConstants,
Instruction[][][] instructionSequences,
BranchTargetFinder branchTargetFinder,
CodeAttributeEditor codeAttributeEditor,
InstructionVisitor extraInstructionVisitor)
{
super(createInstructionSequenceReplacers(patternConstants,
instructionSequences,
branchTargetFinder,
codeAttributeEditor,
extraInstructionVisitor));
}
/**
* Creates an array of InstructionSequenceReplacer instances.
* @param patternConstants any constants referenced by the pattern
* instruction.
* @param instructionSequences the instruction sequences to be replaced,
* with subsequently the sequence pair index,
* the from/to index (0 or 1), and the
* instruction index in the sequence.
* @param branchTargetFinder a branch target finder that has been
* initialized to indicate branch targets
* in the visited code.
* @param codeAttributeEditor a code editor that can be used for
* accumulating changes to the code.
* @param extraInstructionVisitor an optional extra visitor for all deleted
* load instructions.
*/
private static InstructionVisitor[] createInstructionSequenceReplacers(Constant[] patternConstants,
Instruction[][][] instructionSequences,
BranchTargetFinder branchTargetFinder,
CodeAttributeEditor codeAttributeEditor,
InstructionVisitor extraInstructionVisitor)
{
InstructionVisitor[] instructionSequenceReplacers =
new InstructionSequenceReplacer[instructionSequences.length];
for (int index = 0; index < instructionSequenceReplacers.length; index++)
{
Instruction[][] instructionSequencePair = instructionSequences[index];
instructionSequenceReplacers[index] =
new InstructionSequenceReplacer(patternConstants,
instructionSequencePair[PATTERN_INDEX],
instructionSequencePair[REPLACEMENT_INDEX],
branchTargetFinder,
codeAttributeEditor,
extraInstructionVisitor);
}
return instructionSequenceReplacers;
}
}