789 lines
33 KiB
Java
789 lines
33 KiB
Java
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/*
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* Copyright (c) 1994, 2021, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation. Oracle designates this
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* particular file as subject to the "Classpath" exception as provided
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* by Oracle in the LICENSE file that accompanied this code.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*/
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package java.io;
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import java.util.ArrayList;
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import java.util.Arrays;
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import java.util.List;
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import java.util.Objects;
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/**
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* This abstract class is the superclass of all classes representing
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* an input stream of bytes.
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*
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* <p> Applications that need to define a subclass of {@code InputStream}
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* must always provide a method that returns the next byte of input.
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*
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* @author Arthur van Hoff
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* @see java.io.BufferedInputStream
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* @see java.io.ByteArrayInputStream
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* @see java.io.DataInputStream
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* @see java.io.FilterInputStream
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* @see java.io.InputStream#read()
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* @see java.io.OutputStream
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* @see java.io.PushbackInputStream
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* @since 1.0
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*/
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public abstract class InputStream implements Closeable {
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// MAX_SKIP_BUFFER_SIZE is used to determine the maximum buffer size to
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// use when skipping.
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private static final int MAX_SKIP_BUFFER_SIZE = 2048;
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private static final int DEFAULT_BUFFER_SIZE = 8192;
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/**
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* Constructor for subclasses to call.
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*/
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public InputStream() {}
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/**
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* Returns a new {@code InputStream} that reads no bytes. The returned
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* stream is initially open. The stream is closed by calling the
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* {@code close()} method. Subsequent calls to {@code close()} have no
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* effect.
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*
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* <p> While the stream is open, the {@code available()}, {@code read()},
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* {@code read(byte[])}, {@code read(byte[], int, int)},
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* {@code readAllBytes()}, {@code readNBytes(byte[], int, int)},
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* {@code readNBytes(int)}, {@code skip(long)}, {@code skipNBytes(long)},
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* and {@code transferTo()} methods all behave as if end of stream has been
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* reached. After the stream has been closed, these methods all throw
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* {@code IOException}.
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*
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* <p> The {@code markSupported()} method returns {@code false}. The
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* {@code mark()} method does nothing, and the {@code reset()} method
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* throws {@code IOException}.
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*
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* @return an {@code InputStream} which contains no bytes
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*
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* @since 11
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*/
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public static InputStream nullInputStream() {
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return new InputStream() {
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private volatile boolean closed;
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private void ensureOpen() throws IOException {
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if (closed) {
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throw new IOException("Stream closed");
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}
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}
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@Override
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public int available () throws IOException {
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ensureOpen();
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return 0;
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}
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@Override
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public int read() throws IOException {
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ensureOpen();
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return -1;
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}
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@Override
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public int read(byte[] b, int off, int len) throws IOException {
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Objects.checkFromIndexSize(off, len, b.length);
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if (len == 0) {
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return 0;
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}
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ensureOpen();
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return -1;
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}
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@Override
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public byte[] readAllBytes() throws IOException {
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ensureOpen();
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return new byte[0];
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}
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@Override
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public int readNBytes(byte[] b, int off, int len)
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throws IOException {
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Objects.checkFromIndexSize(off, len, b.length);
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ensureOpen();
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return 0;
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}
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@Override
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public byte[] readNBytes(int len) throws IOException {
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if (len < 0) {
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throw new IllegalArgumentException("len < 0");
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}
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ensureOpen();
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return new byte[0];
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}
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@Override
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public long skip(long n) throws IOException {
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ensureOpen();
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return 0L;
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}
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@Override
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public void skipNBytes(long n) throws IOException {
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ensureOpen();
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if (n > 0) {
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throw new EOFException();
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}
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}
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@Override
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public long transferTo(OutputStream out) throws IOException {
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Objects.requireNonNull(out);
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ensureOpen();
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return 0L;
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}
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@Override
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public void close() throws IOException {
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closed = true;
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}
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};
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}
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/**
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* Reads the next byte of data from the input stream. The value byte is
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* returned as an {@code int} in the range {@code 0} to
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* {@code 255}. If no byte is available because the end of the stream
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* has been reached, the value {@code -1} is returned. This method
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* blocks until input data is available, the end of the stream is detected,
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* or an exception is thrown.
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*
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* <p> A subclass must provide an implementation of this method.
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*
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* @return the next byte of data, or {@code -1} if the end of the
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* stream is reached.
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* @throws IOException if an I/O error occurs.
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*/
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public abstract int read() throws IOException;
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/**
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* Reads some number of bytes from the input stream and stores them into
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* the buffer array {@code b}. The number of bytes actually read is
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* returned as an integer. This method blocks until input data is
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* available, end of file is detected, or an exception is thrown.
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*
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* <p> If the length of {@code b} is zero, then no bytes are read and
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* {@code 0} is returned; otherwise, there is an attempt to read at
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* least one byte. If no byte is available because the stream is at the
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* end of the file, the value {@code -1} is returned; otherwise, at
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* least one byte is read and stored into {@code b}.
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*
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* <p> The first byte read is stored into element {@code b[0]}, the
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* next one into {@code b[1]}, and so on. The number of bytes read is,
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* at most, equal to the length of {@code b}. Let <i>k</i> be the
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* number of bytes actually read; these bytes will be stored in elements
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* {@code b[0]} through {@code b[}<i>k</i>{@code -1]},
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* leaving elements {@code b[}<i>k</i>{@code ]} through
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* {@code b[b.length-1]} unaffected.
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*
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* <p> The {@code read(b)} method for class {@code InputStream}
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* has the same effect as: <pre>{@code read(b, 0, b.length) }</pre>
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*
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* @param b the buffer into which the data is read.
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* @return the total number of bytes read into the buffer, or
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* {@code -1} if there is no more data because the end of
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* the stream has been reached.
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* @throws IOException If the first byte cannot be read for any reason
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* other than the end of the file, if the input stream has been
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* closed, or if some other I/O error occurs.
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* @throws NullPointerException if {@code b} is {@code null}.
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* @see java.io.InputStream#read(byte[], int, int)
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*/
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public int read(byte b[]) throws IOException {
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return read(b, 0, b.length);
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}
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/**
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* Reads up to {@code len} bytes of data from the input stream into
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* an array of bytes. An attempt is made to read as many as
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* {@code len} bytes, but a smaller number may be read.
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* The number of bytes actually read is returned as an integer.
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*
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* <p> This method blocks until input data is available, end of file is
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* detected, or an exception is thrown.
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*
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* <p> If {@code len} is zero, then no bytes are read and
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* {@code 0} is returned; otherwise, there is an attempt to read at
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* least one byte. If no byte is available because the stream is at end of
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* file, the value {@code -1} is returned; otherwise, at least one
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* byte is read and stored into {@code b}.
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*
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* <p> The first byte read is stored into element {@code b[off]}, the
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* next one into {@code b[off+1]}, and so on. The number of bytes read
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* is, at most, equal to {@code len}. Let <i>k</i> be the number of
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* bytes actually read; these bytes will be stored in elements
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* {@code b[off]} through {@code b[off+}<i>k</i>{@code -1]},
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* leaving elements {@code b[off+}<i>k</i>{@code ]} through
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* {@code b[off+len-1]} unaffected.
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*
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* <p> In every case, elements {@code b[0]} through
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* {@code b[off-1]} and elements {@code b[off+len]} through
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* {@code b[b.length-1]} are unaffected.
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*
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* <p> The {@code read(b, off, len)} method
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* for class {@code InputStream} simply calls the method
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* {@code read()} repeatedly. If the first such call results in an
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* {@code IOException}, that exception is returned from the call to
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* the {@code read(b,} {@code off,} {@code len)} method. If
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* any subsequent call to {@code read()} results in a
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* {@code IOException}, the exception is caught and treated as if it
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* were end of file; the bytes read up to that point are stored into
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* {@code b} and the number of bytes read before the exception
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* occurred is returned. The default implementation of this method blocks
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* until the requested amount of input data {@code len} has been read,
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* end of file is detected, or an exception is thrown. Subclasses are
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* encouraged to provide a more efficient implementation of this method.
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*
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* @param b the buffer into which the data is read.
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* @param off the start offset in array {@code b}
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* at which the data is written.
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* @param len the maximum number of bytes to read.
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* @return the total number of bytes read into the buffer, or
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* {@code -1} if there is no more data because the end of
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* the stream has been reached.
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* @throws IOException If the first byte cannot be read for any reason
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* other than end of file, or if the input stream has been closed,
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* or if some other I/O error occurs.
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* @throws NullPointerException If {@code b} is {@code null}.
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* @throws IndexOutOfBoundsException If {@code off} is negative,
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* {@code len} is negative, or {@code len} is greater than
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* {@code b.length - off}
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* @see java.io.InputStream#read()
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*/
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public int read(byte b[], int off, int len) throws IOException {
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Objects.checkFromIndexSize(off, len, b.length);
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if (len == 0) {
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return 0;
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}
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int c = read();
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if (c == -1) {
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return -1;
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}
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b[off] = (byte)c;
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int i = 1;
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try {
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for (; i < len ; i++) {
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c = read();
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if (c == -1) {
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break;
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}
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b[off + i] = (byte)c;
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||
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}
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||
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} catch (IOException ee) {
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||
|
|
}
|
||
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return i;
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
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* The maximum size of array to allocate.
|
||
|
|
* Some VMs reserve some header words in an array.
|
||
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* Attempts to allocate larger arrays may result in
|
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* OutOfMemoryError: Requested array size exceeds VM limit
|
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*/
|
||
|
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private static final int MAX_BUFFER_SIZE = Integer.MAX_VALUE - 8;
|
||
|
|
|
||
|
|
/**
|
||
|
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* Reads all remaining bytes from the input stream. This method blocks until
|
||
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* all remaining bytes have been read and end of stream is detected, or an
|
||
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* exception is thrown. This method does not close the input stream.
|
||
|
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*
|
||
|
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* <p> When this stream reaches end of stream, further invocations of this
|
||
|
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* method will return an empty byte array.
|
||
|
|
*
|
||
|
|
* <p> Note that this method is intended for simple cases where it is
|
||
|
|
* convenient to read all bytes into a byte array. It is not intended for
|
||
|
|
* reading input streams with large amounts of data.
|
||
|
|
*
|
||
|
|
* <p> The behavior for the case where the input stream is <i>asynchronously
|
||
|
|
* closed</i>, or the thread interrupted during the read, is highly input
|
||
|
|
* stream specific, and therefore not specified.
|
||
|
|
*
|
||
|
|
* <p> If an I/O error occurs reading from the input stream, then it may do
|
||
|
|
* so after some, but not all, bytes have been read. Consequently the input
|
||
|
|
* stream may not be at end of stream and may be in an inconsistent state.
|
||
|
|
* It is strongly recommended that the stream be promptly closed if an I/O
|
||
|
|
* error occurs.
|
||
|
|
*
|
||
|
|
* @implSpec
|
||
|
|
* This method invokes {@link #readNBytes(int)} with a length of
|
||
|
|
* {@link Integer#MAX_VALUE}.
|
||
|
|
*
|
||
|
|
* @return a byte array containing the bytes read from this input stream
|
||
|
|
* @throws IOException if an I/O error occurs
|
||
|
|
* @throws OutOfMemoryError if an array of the required size cannot be
|
||
|
|
* allocated.
|
||
|
|
*
|
||
|
|
* @since 9
|
||
|
|
*/
|
||
|
|
public byte[] readAllBytes() throws IOException {
|
||
|
|
return readNBytes(Integer.MAX_VALUE);
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Reads up to a specified number of bytes from the input stream. This
|
||
|
|
* method blocks until the requested number of bytes has been read, end
|
||
|
|
* of stream is detected, or an exception is thrown. This method does not
|
||
|
|
* close the input stream.
|
||
|
|
*
|
||
|
|
* <p> The length of the returned array equals the number of bytes read
|
||
|
|
* from the stream. If {@code len} is zero, then no bytes are read and
|
||
|
|
* an empty byte array is returned. Otherwise, up to {@code len} bytes
|
||
|
|
* are read from the stream. Fewer than {@code len} bytes may be read if
|
||
|
|
* end of stream is encountered.
|
||
|
|
*
|
||
|
|
* <p> When this stream reaches end of stream, further invocations of this
|
||
|
|
* method will return an empty byte array.
|
||
|
|
*
|
||
|
|
* <p> Note that this method is intended for simple cases where it is
|
||
|
|
* convenient to read the specified number of bytes into a byte array. The
|
||
|
|
* total amount of memory allocated by this method is proportional to the
|
||
|
|
* number of bytes read from the stream which is bounded by {@code len}.
|
||
|
|
* Therefore, the method may be safely called with very large values of
|
||
|
|
* {@code len} provided sufficient memory is available.
|
||
|
|
*
|
||
|
|
* <p> The behavior for the case where the input stream is <i>asynchronously
|
||
|
|
* closed</i>, or the thread interrupted during the read, is highly input
|
||
|
|
* stream specific, and therefore not specified.
|
||
|
|
*
|
||
|
|
* <p> If an I/O error occurs reading from the input stream, then it may do
|
||
|
|
* so after some, but not all, bytes have been read. Consequently the input
|
||
|
|
* stream may not be at end of stream and may be in an inconsistent state.
|
||
|
|
* It is strongly recommended that the stream be promptly closed if an I/O
|
||
|
|
* error occurs.
|
||
|
|
*
|
||
|
|
* @implNote
|
||
|
|
* The number of bytes allocated to read data from this stream and return
|
||
|
|
* the result is bounded by {@code 2*(long)len}, inclusive.
|
||
|
|
*
|
||
|
|
* @param len the maximum number of bytes to read
|
||
|
|
* @return a byte array containing the bytes read from this input stream
|
||
|
|
* @throws IllegalArgumentException if {@code length} is negative
|
||
|
|
* @throws IOException if an I/O error occurs
|
||
|
|
* @throws OutOfMemoryError if an array of the required size cannot be
|
||
|
|
* allocated.
|
||
|
|
*
|
||
|
|
* @since 11
|
||
|
|
*/
|
||
|
|
public byte[] readNBytes(int len) throws IOException {
|
||
|
|
if (len < 0) {
|
||
|
|
throw new IllegalArgumentException("len < 0");
|
||
|
|
}
|
||
|
|
|
||
|
|
List<byte[]> bufs = null;
|
||
|
|
byte[] result = null;
|
||
|
|
int total = 0;
|
||
|
|
int remaining = len;
|
||
|
|
int n;
|
||
|
|
do {
|
||
|
|
byte[] buf = new byte[Math.min(remaining, DEFAULT_BUFFER_SIZE)];
|
||
|
|
int nread = 0;
|
||
|
|
|
||
|
|
// read to EOF which may read more or less than buffer size
|
||
|
|
while ((n = read(buf, nread,
|
||
|
|
Math.min(buf.length - nread, remaining))) > 0) {
|
||
|
|
nread += n;
|
||
|
|
remaining -= n;
|
||
|
|
}
|
||
|
|
|
||
|
|
if (nread > 0) {
|
||
|
|
if (MAX_BUFFER_SIZE - total < nread) {
|
||
|
|
throw new OutOfMemoryError("Required array size too large");
|
||
|
|
}
|
||
|
|
if (nread < buf.length) {
|
||
|
|
buf = Arrays.copyOfRange(buf, 0, nread);
|
||
|
|
}
|
||
|
|
total += nread;
|
||
|
|
if (result == null) {
|
||
|
|
result = buf;
|
||
|
|
} else {
|
||
|
|
if (bufs == null) {
|
||
|
|
bufs = new ArrayList<>();
|
||
|
|
bufs.add(result);
|
||
|
|
}
|
||
|
|
bufs.add(buf);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
// if the last call to read returned -1 or the number of bytes
|
||
|
|
// requested have been read then break
|
||
|
|
} while (n >= 0 && remaining > 0);
|
||
|
|
|
||
|
|
if (bufs == null) {
|
||
|
|
if (result == null) {
|
||
|
|
return new byte[0];
|
||
|
|
}
|
||
|
|
return result.length == total ?
|
||
|
|
result : Arrays.copyOf(result, total);
|
||
|
|
}
|
||
|
|
|
||
|
|
result = new byte[total];
|
||
|
|
int offset = 0;
|
||
|
|
remaining = total;
|
||
|
|
for (byte[] b : bufs) {
|
||
|
|
int count = Math.min(b.length, remaining);
|
||
|
|
System.arraycopy(b, 0, result, offset, count);
|
||
|
|
offset += count;
|
||
|
|
remaining -= count;
|
||
|
|
}
|
||
|
|
|
||
|
|
return result;
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Reads the requested number of bytes from the input stream into the given
|
||
|
|
* byte array. This method blocks until {@code len} bytes of input data have
|
||
|
|
* been read, end of stream is detected, or an exception is thrown. The
|
||
|
|
* number of bytes actually read, possibly zero, is returned. This method
|
||
|
|
* does not close the input stream.
|
||
|
|
*
|
||
|
|
* <p> In the case where end of stream is reached before {@code len} bytes
|
||
|
|
* have been read, then the actual number of bytes read will be returned.
|
||
|
|
* When this stream reaches end of stream, further invocations of this
|
||
|
|
* method will return zero.
|
||
|
|
*
|
||
|
|
* <p> If {@code len} is zero, then no bytes are read and {@code 0} is
|
||
|
|
* returned; otherwise, there is an attempt to read up to {@code len} bytes.
|
||
|
|
*
|
||
|
|
* <p> The first byte read is stored into element {@code b[off]}, the next
|
||
|
|
* one in to {@code b[off+1]}, and so on. The number of bytes read is, at
|
||
|
|
* most, equal to {@code len}. Let <i>k</i> be the number of bytes actually
|
||
|
|
* read; these bytes will be stored in elements {@code b[off]} through
|
||
|
|
* {@code b[off+}<i>k</i>{@code -1]}, leaving elements {@code b[off+}<i>k</i>
|
||
|
|
* {@code ]} through {@code b[off+len-1]} unaffected.
|
||
|
|
*
|
||
|
|
* <p> The behavior for the case where the input stream is <i>asynchronously
|
||
|
|
* closed</i>, or the thread interrupted during the read, is highly input
|
||
|
|
* stream specific, and therefore not specified.
|
||
|
|
*
|
||
|
|
* <p> If an I/O error occurs reading from the input stream, then it may do
|
||
|
|
* so after some, but not all, bytes of {@code b} have been updated with
|
||
|
|
* data from the input stream. Consequently the input stream and {@code b}
|
||
|
|
* may be in an inconsistent state. It is strongly recommended that the
|
||
|
|
* stream be promptly closed if an I/O error occurs.
|
||
|
|
*
|
||
|
|
* @param b the byte array into which the data is read
|
||
|
|
* @param off the start offset in {@code b} at which the data is written
|
||
|
|
* @param len the maximum number of bytes to read
|
||
|
|
* @return the actual number of bytes read into the buffer
|
||
|
|
* @throws IOException if an I/O error occurs
|
||
|
|
* @throws NullPointerException if {@code b} is {@code null}
|
||
|
|
* @throws IndexOutOfBoundsException If {@code off} is negative, {@code len}
|
||
|
|
* is negative, or {@code len} is greater than {@code b.length - off}
|
||
|
|
*
|
||
|
|
* @since 9
|
||
|
|
*/
|
||
|
|
public int readNBytes(byte[] b, int off, int len) throws IOException {
|
||
|
|
Objects.checkFromIndexSize(off, len, b.length);
|
||
|
|
|
||
|
|
int n = 0;
|
||
|
|
while (n < len) {
|
||
|
|
int count = read(b, off + n, len - n);
|
||
|
|
if (count < 0)
|
||
|
|
break;
|
||
|
|
n += count;
|
||
|
|
}
|
||
|
|
return n;
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Skips over and discards {@code n} bytes of data from this input
|
||
|
|
* stream. The {@code skip} method may, for a variety of reasons, end
|
||
|
|
* up skipping over some smaller number of bytes, possibly {@code 0}.
|
||
|
|
* This may result from any of a number of conditions; reaching end of file
|
||
|
|
* before {@code n} bytes have been skipped is only one possibility.
|
||
|
|
* The actual number of bytes skipped is returned. If {@code n} is
|
||
|
|
* negative, the {@code skip} method for class {@code InputStream} always
|
||
|
|
* returns 0, and no bytes are skipped. Subclasses may handle the negative
|
||
|
|
* value differently.
|
||
|
|
*
|
||
|
|
* <p> The {@code skip} method implementation of this class creates a
|
||
|
|
* byte array and then repeatedly reads into it until {@code n} bytes
|
||
|
|
* have been read or the end of the stream has been reached. Subclasses are
|
||
|
|
* encouraged to provide a more efficient implementation of this method.
|
||
|
|
* For instance, the implementation may depend on the ability to seek.
|
||
|
|
*
|
||
|
|
* @param n the number of bytes to be skipped.
|
||
|
|
* @return the actual number of bytes skipped which might be zero.
|
||
|
|
* @throws IOException if an I/O error occurs.
|
||
|
|
* @see java.io.InputStream#skipNBytes(long)
|
||
|
|
*/
|
||
|
|
public long skip(long n) throws IOException {
|
||
|
|
long remaining = n;
|
||
|
|
int nr;
|
||
|
|
|
||
|
|
if (n <= 0) {
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
int size = (int)Math.min(MAX_SKIP_BUFFER_SIZE, remaining);
|
||
|
|
byte[] skipBuffer = new byte[size];
|
||
|
|
while (remaining > 0) {
|
||
|
|
nr = read(skipBuffer, 0, (int)Math.min(size, remaining));
|
||
|
|
if (nr < 0) {
|
||
|
|
break;
|
||
|
|
}
|
||
|
|
remaining -= nr;
|
||
|
|
}
|
||
|
|
|
||
|
|
return n - remaining;
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Skips over and discards exactly {@code n} bytes of data from this input
|
||
|
|
* stream. If {@code n} is zero, then no bytes are skipped.
|
||
|
|
* If {@code n} is negative, then no bytes are skipped.
|
||
|
|
* Subclasses may handle the negative value differently.
|
||
|
|
*
|
||
|
|
* <p> This method blocks until the requested number of bytes has been
|
||
|
|
* skipped, end of file is reached, or an exception is thrown.
|
||
|
|
*
|
||
|
|
* <p> If end of stream is reached before the stream is at the desired
|
||
|
|
* position, then an {@code EOFException} is thrown.
|
||
|
|
*
|
||
|
|
* <p> If an I/O error occurs, then the input stream may be
|
||
|
|
* in an inconsistent state. It is strongly recommended that the
|
||
|
|
* stream be promptly closed if an I/O error occurs.
|
||
|
|
*
|
||
|
|
* @implNote
|
||
|
|
* Subclasses are encouraged to provide a more efficient implementation
|
||
|
|
* of this method.
|
||
|
|
*
|
||
|
|
* @implSpec
|
||
|
|
* If {@code n} is zero or negative, then no bytes are skipped.
|
||
|
|
* If {@code n} is positive, the default implementation of this method
|
||
|
|
* invokes {@link #skip(long) skip()} repeatedly with its parameter equal
|
||
|
|
* to the remaining number of bytes to skip until the requested number
|
||
|
|
* of bytes has been skipped or an error condition occurs. If at any
|
||
|
|
* point the return value of {@code skip()} is negative or greater than the
|
||
|
|
* remaining number of bytes to be skipped, then an {@code IOException} is
|
||
|
|
* thrown. If {@code skip()} ever returns zero, then {@link #read()} is
|
||
|
|
* invoked to read a single byte, and if it returns {@code -1}, then an
|
||
|
|
* {@code EOFException} is thrown. Any exception thrown by {@code skip()}
|
||
|
|
* or {@code read()} will be propagated.
|
||
|
|
*
|
||
|
|
* @param n the number of bytes to be skipped.
|
||
|
|
* @throws EOFException if end of stream is encountered before the
|
||
|
|
* stream can be positioned {@code n} bytes beyond its position
|
||
|
|
* when this method was invoked.
|
||
|
|
* @throws IOException if the stream cannot be positioned properly or
|
||
|
|
* if an I/O error occurs.
|
||
|
|
* @see java.io.InputStream#skip(long)
|
||
|
|
*
|
||
|
|
* @since 12
|
||
|
|
*/
|
||
|
|
public void skipNBytes(long n) throws IOException {
|
||
|
|
while (n > 0) {
|
||
|
|
long ns = skip(n);
|
||
|
|
if (ns > 0 && ns <= n) {
|
||
|
|
// adjust number to skip
|
||
|
|
n -= ns;
|
||
|
|
} else if (ns == 0) { // no bytes skipped
|
||
|
|
// read one byte to check for EOS
|
||
|
|
if (read() == -1) {
|
||
|
|
throw new EOFException();
|
||
|
|
}
|
||
|
|
// one byte read so decrement number to skip
|
||
|
|
n--;
|
||
|
|
} else { // skipped negative or too many bytes
|
||
|
|
throw new IOException("Unable to skip exactly");
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Returns an estimate of the number of bytes that can be read (or skipped
|
||
|
|
* over) from this input stream without blocking, which may be 0, or 0 when
|
||
|
|
* end of stream is detected. The read might be on the same thread or
|
||
|
|
* another thread. A single read or skip of this many bytes will not block,
|
||
|
|
* but may read or skip fewer bytes.
|
||
|
|
*
|
||
|
|
* <p> Note that while some implementations of {@code InputStream} will
|
||
|
|
* return the total number of bytes in the stream, many will not. It is
|
||
|
|
* never correct to use the return value of this method to allocate
|
||
|
|
* a buffer intended to hold all data in this stream.
|
||
|
|
*
|
||
|
|
* <p> A subclass's implementation of this method may choose to throw an
|
||
|
|
* {@link IOException} if this input stream has been closed by invoking the
|
||
|
|
* {@link #close()} method.
|
||
|
|
*
|
||
|
|
* <p> The {@code available} method of {@code InputStream} always returns
|
||
|
|
* {@code 0}.
|
||
|
|
*
|
||
|
|
* <p> This method should be overridden by subclasses.
|
||
|
|
*
|
||
|
|
* @return an estimate of the number of bytes that can be read (or
|
||
|
|
* skipped over) from this input stream without blocking or
|
||
|
|
* {@code 0} when it reaches the end of the input stream.
|
||
|
|
* @throws IOException if an I/O error occurs.
|
||
|
|
*/
|
||
|
|
public int available() throws IOException {
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Closes this input stream and releases any system resources associated
|
||
|
|
* with the stream.
|
||
|
|
*
|
||
|
|
* <p> The {@code close} method of {@code InputStream} does
|
||
|
|
* nothing.
|
||
|
|
*
|
||
|
|
* @throws IOException if an I/O error occurs.
|
||
|
|
*/
|
||
|
|
public void close() throws IOException {}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Marks the current position in this input stream. A subsequent call to
|
||
|
|
* the {@code reset} method repositions this stream at the last marked
|
||
|
|
* position so that subsequent reads re-read the same bytes.
|
||
|
|
*
|
||
|
|
* <p> The {@code readlimit} arguments tells this input stream to
|
||
|
|
* allow that many bytes to be read before the mark position gets
|
||
|
|
* invalidated.
|
||
|
|
*
|
||
|
|
* <p> The general contract of {@code mark} is that, if the method
|
||
|
|
* {@code markSupported} returns {@code true}, the stream somehow
|
||
|
|
* remembers all the bytes read after the call to {@code mark} and
|
||
|
|
* stands ready to supply those same bytes again if and whenever the method
|
||
|
|
* {@code reset} is called. However, the stream is not required to
|
||
|
|
* remember any data at all if more than {@code readlimit} bytes are
|
||
|
|
* read from the stream before {@code reset} is called.
|
||
|
|
*
|
||
|
|
* <p> Marking a closed stream should not have any effect on the stream.
|
||
|
|
*
|
||
|
|
* <p> The {@code mark} method of {@code InputStream} does
|
||
|
|
* nothing.
|
||
|
|
*
|
||
|
|
* @param readlimit the maximum limit of bytes that can be read before
|
||
|
|
* the mark position becomes invalid.
|
||
|
|
* @see java.io.InputStream#reset()
|
||
|
|
*/
|
||
|
|
public synchronized void mark(int readlimit) {}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Repositions this stream to the position at the time the
|
||
|
|
* {@code mark} method was last called on this input stream.
|
||
|
|
*
|
||
|
|
* <p> The general contract of {@code reset} is:
|
||
|
|
*
|
||
|
|
* <ul>
|
||
|
|
* <li> If the method {@code markSupported} returns
|
||
|
|
* {@code true}, then:
|
||
|
|
*
|
||
|
|
* <ul><li> If the method {@code mark} has not been called since
|
||
|
|
* the stream was created, or the number of bytes read from the stream
|
||
|
|
* since {@code mark} was last called is larger than the argument
|
||
|
|
* to {@code mark} at that last call, then an
|
||
|
|
* {@code IOException} might be thrown.
|
||
|
|
*
|
||
|
|
* <li> If such an {@code IOException} is not thrown, then the
|
||
|
|
* stream is reset to a state such that all the bytes read since the
|
||
|
|
* most recent call to {@code mark} (or since the start of the
|
||
|
|
* file, if {@code mark} has not been called) will be resupplied
|
||
|
|
* to subsequent callers of the {@code read} method, followed by
|
||
|
|
* any bytes that otherwise would have been the next input data as of
|
||
|
|
* the time of the call to {@code reset}. </ul>
|
||
|
|
*
|
||
|
|
* <li> If the method {@code markSupported} returns
|
||
|
|
* {@code false}, then:
|
||
|
|
*
|
||
|
|
* <ul><li> The call to {@code reset} may throw an
|
||
|
|
* {@code IOException}.
|
||
|
|
*
|
||
|
|
* <li> If an {@code IOException} is not thrown, then the stream
|
||
|
|
* is reset to a fixed state that depends on the particular type of the
|
||
|
|
* input stream and how it was created. The bytes that will be supplied
|
||
|
|
* to subsequent callers of the {@code read} method depend on the
|
||
|
|
* particular type of the input stream. </ul></ul>
|
||
|
|
*
|
||
|
|
* <p>The method {@code reset} for class {@code InputStream}
|
||
|
|
* does nothing except throw an {@code IOException}.
|
||
|
|
*
|
||
|
|
* @throws IOException if this stream has not been marked or if the
|
||
|
|
* mark has been invalidated.
|
||
|
|
* @see java.io.InputStream#mark(int)
|
||
|
|
* @see java.io.IOException
|
||
|
|
*/
|
||
|
|
public synchronized void reset() throws IOException {
|
||
|
|
throw new IOException("mark/reset not supported");
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Tests if this input stream supports the {@code mark} and
|
||
|
|
* {@code reset} methods. Whether or not {@code mark} and
|
||
|
|
* {@code reset} are supported is an invariant property of a
|
||
|
|
* particular input stream instance. The {@code markSupported} method
|
||
|
|
* of {@code InputStream} returns {@code false}.
|
||
|
|
*
|
||
|
|
* @return {@code true} if this stream instance supports the mark
|
||
|
|
* and reset methods; {@code false} otherwise.
|
||
|
|
* @see java.io.InputStream#mark(int)
|
||
|
|
* @see java.io.InputStream#reset()
|
||
|
|
*/
|
||
|
|
public boolean markSupported() {
|
||
|
|
return false;
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Reads all bytes from this input stream and writes the bytes to the
|
||
|
|
* given output stream in the order that they are read. On return, this
|
||
|
|
* input stream will be at end of stream. This method does not close either
|
||
|
|
* stream.
|
||
|
|
* <p>
|
||
|
|
* This method may block indefinitely reading from the input stream, or
|
||
|
|
* writing to the output stream. The behavior for the case where the input
|
||
|
|
* and/or output stream is <i>asynchronously closed</i>, or the thread
|
||
|
|
* interrupted during the transfer, is highly input and output stream
|
||
|
|
* specific, and therefore not specified.
|
||
|
|
* <p>
|
||
|
|
* If an I/O error occurs reading from the input stream or writing to the
|
||
|
|
* output stream, then it may do so after some bytes have been read or
|
||
|
|
* written. Consequently the input stream may not be at end of stream and
|
||
|
|
* one, or both, streams may be in an inconsistent state. It is strongly
|
||
|
|
* recommended that both streams be promptly closed if an I/O error occurs.
|
||
|
|
*
|
||
|
|
* @param out the output stream, non-null
|
||
|
|
* @return the number of bytes transferred
|
||
|
|
* @throws IOException if an I/O error occurs when reading or writing
|
||
|
|
* @throws NullPointerException if {@code out} is {@code null}
|
||
|
|
*
|
||
|
|
* @since 9
|
||
|
|
*/
|
||
|
|
public long transferTo(OutputStream out) throws IOException {
|
||
|
|
Objects.requireNonNull(out, "out");
|
||
|
|
long transferred = 0;
|
||
|
|
byte[] buffer = new byte[DEFAULT_BUFFER_SIZE];
|
||
|
|
int read;
|
||
|
|
while ((read = this.read(buffer, 0, DEFAULT_BUFFER_SIZE)) >= 0) {
|
||
|
|
out.write(buffer, 0, read);
|
||
|
|
transferred += read;
|
||
|
|
}
|
||
|
|
return transferred;
|
||
|
|
}
|
||
|
|
}
|