211 lines
5.8 KiB
Java
211 lines
5.8 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 it.cavallium.stream;
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import it.cavallium.buffer.IgnoreCoverage;
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import it.unimi.dsi.fastutil.bytes.ByteArrays;
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import java.util.Arrays;
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import java.util.HexFormat;
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import java.util.Objects;
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import static java.util.Objects.checkFromToIndex;
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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 static final HexFormat HEX = HexFormat.of();
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private static final int MAX_PREVIEW_LENGTH = 128;
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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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private final int wrappedFrom;
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private final int wrappedTo;
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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 arrayPosition;
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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 = wrappedFrom = length = initialLength = 0;
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wrappedTo = Integer.MAX_VALUE;
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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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@IgnoreCoverage
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public SafeByteArrayOutputStream(final byte[] a) {
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this(a, 0, 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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checkFromToIndex(from, to, a.length);
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wrapped = true;
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array = a;
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initialPosition = wrappedFrom = arrayPosition = from;
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initialLength = length = to - from;
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wrappedTo = to;
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}
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private void ensureWrappedBounds(int fromArrayPosition, int toArrayPosition) {
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Objects.checkFromToIndex(fromArrayPosition - wrappedFrom, toArrayPosition - wrappedFrom, wrappedTo - wrappedFrom);
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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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arrayPosition = 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 (wrapped) {
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ensureWrappedBounds(arrayPosition, arrayPosition + 1);
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} else if (arrayPosition >= array.length) {
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array = ByteArrays.grow(array, arrayPosition + 1, length);
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}
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array[arrayPosition++] = (byte)b;
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if (length < arrayPosition) length = arrayPosition;
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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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if (wrapped) {
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ensureWrappedBounds(arrayPosition, arrayPosition + len);
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}
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Objects.checkFromIndexSize(off, len, b.length);
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growBy(len);
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System.arraycopy(b, off, array, arrayPosition, len);
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if (arrayPosition + len > length) length = arrayPosition += len;
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}
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private void growBy(int len) {
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if (wrapped) {
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ensureWrappedBounds(arrayPosition, arrayPosition + len);
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}
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if (arrayPosition + len > array.length) {
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if (wrapped) {
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throw new ArrayIndexOutOfBoundsException(arrayPosition + len - 1);
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} else {
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array = ByteArrays.grow(array, arrayPosition + len, arrayPosition);
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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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if (wrapped) {
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arrayPosition = (int) (newPosition + wrappedFrom);
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} else {
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arrayPosition = (int)newPosition;
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}
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}
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@Override
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public long position() {
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if (wrapped) {
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return arrayPosition - wrappedFrom;
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} else {
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return arrayPosition;
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}
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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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* This method copies the array
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*/
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public byte[] toByteArray() {
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if (wrapped) {
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return Arrays.copyOfRange(array, wrappedFrom, wrappedTo);
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} else {
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return java.util.Arrays.copyOf(array, length);
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}
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}
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@Override
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public String toString() {
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return "SafeByteArrayOutputStream[" + toHexPreview() + "]";
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}
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private String toHexPreview() {
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int len;
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int from;
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String prefix;
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if (wrapped) {
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prefix = "(wrapped from " + wrappedFrom + " to " + wrappedTo + ") ";
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from = wrappedFrom;
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len = wrappedTo - wrappedFrom;
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} else {
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prefix = "";
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from = 0;
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len = length;
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}
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return prefix + HEX.formatHex(this.array, from, (Math.min(len, MAX_PREVIEW_LENGTH) + from)) + ((len > MAX_PREVIEW_LENGTH) ? "..." : "");
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}
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}
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