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/*
* Copyright (C) 2007 The Android Open Source Project
*
* Licensed 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.android.dx.dex.code;
import java.util.ArrayList;
/**
* Destination for {@link DalvInsn} instances being output. This class
* receives and collects instructions in two pieces — a primary
* list and a suffix (generally consisting of adjunct data referred to
* by the primary list, such as switch case tables) — which it
* merges and emits back out in the form of a {@link DalvInsnList}
* instance.
*/
public final class OutputCollector {
/**
* non-null; the associated finisher (which holds the instruction
* list in-progress)
*/
private final OutputFinisher finisher;
/**
* null-ok; suffix for the output, or <code>null</code> if the suffix
* has been appended to the main output (by {@link #appendSuffixToOutput})
*/
private ArrayList<DalvInsn> suffix;
/**
* Constructs an instance.
*
* @param initialCapacity >= 0; initial capacity of the output list
* @param suffixInitialCapacity >= 0; initial capacity of the output
* suffix
* @param regCount >= 0; register count for the method
*/
public OutputCollector(int initialCapacity, int suffixInitialCapacity,
int regCount) {
this.finisher = new OutputFinisher(initialCapacity, regCount);
this.suffix = new ArrayList<DalvInsn>(suffixInitialCapacity);
}
/**
* Adds an instruction to the output.
*
* @param insn non-null; the instruction to add
*/
public void add(DalvInsn insn) {
finisher.add(insn);
}
/**
* Reverses a branch which is buried a given number of instructions
* backward in the output. It is illegal to call this unless the
* indicated instruction really is a reversible branch.
*
* @param which how many instructions back to find the branch;
* <code>0</code> is the most recently added instruction,
* <code>1</code> is the instruction before that, etc.
* @param newTarget non-null; the new target for the reversed branch
*/
public void reverseBranch(int which, CodeAddress newTarget) {
finisher.reverseBranch(which, newTarget);
}
/**
* Adds an instruction to the output suffix.
*
* @param insn non-null; the instruction to add
*/
public void addSuffix(DalvInsn insn) {
suffix.add(insn);
}
/**
* Gets the results of all the calls on this instance, in the form of
* an {@link OutputFinisher}.
*
* @return non-null; the output finisher
* @throws UnsupportedOperationException if this method has
* already been called
*/
public OutputFinisher getFinisher() {
if (suffix == null) {
throw new UnsupportedOperationException("already processed");
}
appendSuffixToOutput();
return finisher;
}
/**
* Helper for {@link #getFinisher}, which appends the suffix to
* the primary output.
*/
private void appendSuffixToOutput() {
int size = suffix.size();
for (int i = 0; i < size; i++) {
finisher.add(suffix.get(i));
}
suffix = null;
}
}
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