156 lines
4.2 KiB
Java
156 lines
4.2 KiB
Java
/*
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* Copyright (C) 2005-2022 Sebastiano Vigna
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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package org.warp.commonutils.stream;
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import it.unimi.dsi.fastutil.Arrays;
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import it.unimi.dsi.fastutil.bytes.ByteArrays;
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/** Simple, fast byte-array output stream that exposes the backing array.
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*
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* <p>{@link java.io.ByteArrayOutputStream} is nice, but to get its content you
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* must generate each time a new object. This doesn't happen here.
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*
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* <p>This class will automatically enlarge the backing array, doubling its
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* size whenever new space is needed. The {@link #reset()} method will
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* mark the content as empty, but will not decrease the capacity: use
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* {@link #trim()} for that purpose.
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*
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* @author Sebastiano Vigna
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*/
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public class SafeByteArrayOutputStream extends SafeMeasurableOutputStream implements SafeRepositionableStream {
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/** The array backing the output stream. */
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public static final int DEFAULT_INITIAL_CAPACITY = 16;
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private final boolean wrapped;
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private final int initialPosition;
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private final int initialLength;
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/** The array backing the output stream. */
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public byte[] array;
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/** The number of valid bytes in {@link #array}. */
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public int length;
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/** The current writing position. */
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private int position;
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/** Creates a new array output stream with an initial capacity of {@link #DEFAULT_INITIAL_CAPACITY} bytes. */
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public SafeByteArrayOutputStream() {
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this(DEFAULT_INITIAL_CAPACITY);
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}
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/** Creates a new array output stream with a given initial capacity.
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*
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* @param initialCapacity the initial length of the backing array.
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*/
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public SafeByteArrayOutputStream(final int initialCapacity) {
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array = new byte[initialCapacity];
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wrapped = false;
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initialPosition = 0;
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initialLength = 0;
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}
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/** Creates a new array output stream wrapping a given byte array.
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*
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* @param a the byte array to wrap.
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*/
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public SafeByteArrayOutputStream(final byte[] a) {
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array = a;
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wrapped = true;
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initialPosition = 0;
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initialLength = a.length;
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}
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/** Creates a new array output stream wrapping a given byte array.
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*
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* @param a the byte array to wrap.
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*/
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public SafeByteArrayOutputStream(final byte[] a, int from, int to) {
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Arrays.ensureFromTo(a.length, from, to);
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wrapped = true;
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array = a;
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initialPosition = from;
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initialLength = to;
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position = from;
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length = to - from;
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}
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/** Marks this array output stream as empty. */
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public void reset() {
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length = initialLength;
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position = initialPosition;
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}
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/** Ensures that the length of the backing array is equal to {@link #length}. */
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public void trim() {
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if (!wrapped) {
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array = ByteArrays.trim(array, length);
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}
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}
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public void ensureWritable(int size) {
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growBy(size);
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}
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@Override
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public void write(final int b) {
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if (position >= array.length) {
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if (wrapped) {
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throw new ArrayIndexOutOfBoundsException(position);
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} else {
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array = ByteArrays.grow(array, position + 1, length);
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}
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}
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array[position++] = (byte)b;
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if (length < position) length = position;
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}
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@Override
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public void write(final byte[] b, final int off, final int len) {
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ByteArrays.ensureOffsetLength(b, off, len);
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growBy(len);
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System.arraycopy(b, off, array, position, len);
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if (position + len > length) length = position += len;
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}
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private void growBy(int len) {
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if (position + len > array.length) {
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if (wrapped) {
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throw new ArrayIndexOutOfBoundsException(position + len - 1);
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} else {
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array = ByteArrays.grow(array, position + len, position);
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}
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}
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}
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@Override
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public void position(final long newPosition) {
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position = (int)newPosition;
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}
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@Override
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public long position() {
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return position;
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}
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@Override
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public long length() {
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return length;
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}
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}
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