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- /*
- Copyright (c) 2013 James Ahlborn
-
- 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.healthmarketscience.jackcess.impl;
-
- import java.nio.ByteBuffer;
- import java.util.ArrayList;
- import java.util.List;
-
-
- /**
- * Utility class for constructing {@code byte[]s} where the final size of the
- * data is not known beforehand. The API is similar to {@code ByteBuffer} but
- * the data is not actually written to a {@code byte[]} until {@link
- * #toBuffer} or {@link #toArray} is called.
- *
- * @author James Ahlborn
- */
- public class ByteArrayBuilder
- {
- private int _pos;
- private final List<Data> _data = new ArrayList<Data>();
-
- public ByteArrayBuilder() {
- }
-
- public int position() {
- return _pos;
- }
-
- public ByteArrayBuilder reserveInt() {
- return reserve(4);
- }
-
- public ByteArrayBuilder reserveShort() {
- return reserve(2);
- }
-
- public ByteArrayBuilder reserve(int bytes) {
- _pos += bytes;
- return this;
- }
-
- public ByteArrayBuilder put(byte val) {
- return put(new ByteData(_pos, val));
- }
-
- public ByteArrayBuilder putInt(int val) {
- return putInt(_pos, val);
- }
-
- public ByteArrayBuilder putInt(int pos, int val) {
- return put(new IntData(pos, val));
- }
-
- public ByteArrayBuilder putShort(short val) {
- return putShort(_pos, val);
- }
-
- public ByteArrayBuilder putShort(int pos, short val) {
- return put(new ShortData(pos, val));
- }
-
- public ByteArrayBuilder put(byte[] val) {
- return put(new BytesData(_pos, val));
- }
-
- public ByteArrayBuilder put(ByteBuffer val) {
- return put(new BufData(_pos, val));
- }
-
- private ByteArrayBuilder put(Data data) {
- _data.add(data);
- int endPos = data.getEndPos();
- if(endPos > _pos) {
- _pos = endPos;
- }
- return this;
- }
-
- public ByteBuffer toBuffer() {
- return toBuffer(PageChannel.wrap(new byte[_pos]));
- }
-
- public ByteBuffer toBuffer(ByteBuffer buf) {
- for(Data data : _data) {
- data.write(buf);
- }
- buf.rewind();
- return buf;
- }
-
- public byte[] toArray() {
- return toBuffer().array();
- }
-
- private static abstract class Data
- {
- private int _pos;
-
- protected Data(int pos) {
- _pos = pos;
- }
-
- public int getPos() {
- return _pos;
- }
-
- public int getEndPos() {
- return getPos() + size();
- }
-
- public abstract int size();
-
- public abstract void write(ByteBuffer buf);
- }
-
- private static final class IntData extends Data
- {
- private final int _val;
-
- private IntData(int pos, int val) {
- super(pos);
- _val = val;
- }
-
- @Override
- public int size() {
- return 4;
- }
-
- @Override
- public void write(ByteBuffer buf) {
- buf.putInt(getPos(), _val);
- }
- }
-
- private static final class ShortData extends Data
- {
- private final short _val;
-
- private ShortData(int pos, short val) {
- super(pos);
- _val = val;
- }
-
- @Override
- public int size() {
- return 2;
- }
-
- @Override
- public void write(ByteBuffer buf) {
- buf.putShort(getPos(), _val);
- }
- }
-
- private static final class ByteData extends Data
- {
- private final byte _val;
-
- private ByteData(int pos, byte val) {
- super(pos);
- _val = val;
- }
-
- @Override
- public int size() {
- return 1;
- }
-
- @Override
- public void write(ByteBuffer buf) {
- buf.put(getPos(), _val);
- }
- }
-
- private static final class BytesData extends Data
- {
- private final byte[] _val;
-
- private BytesData(int pos, byte[] val) {
- super(pos);
- _val = val;
- }
-
- @Override
- public int size() {
- return _val.length;
- }
-
- @Override
- public void write(ByteBuffer buf) {
- buf.position(getPos());
- buf.put(_val);
- }
- }
-
- private static final class BufData extends Data
- {
- private final ByteBuffer _val;
-
- private BufData(int pos, ByteBuffer val) {
- super(pos);
- _val = val;
- }
-
- @Override
- public int size() {
- return _val.remaining();
- }
-
- @Override
- public void write(ByteBuffer buf) {
- buf.position(getPos());
- buf.put(_val);
- }
- }
- }
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