/* |
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* Copyright (c) 1994, 2018, 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</code> |
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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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* 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)}, and |
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* {@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 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</code> in the range <code>0</code> to |
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* <code>255</code>. If no byte is available because the end of the stream |
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* has been reached, the value <code>-1</code> 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</code> if the end of the |
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* stream is reached. |
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* @exception 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</code>. 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</code> is zero, then no bytes are read and |
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* <code>0</code> 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</code> is returned; otherwise, at |
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* least one byte is read and stored into <code>b</code>. |
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* |
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* <p> The first byte read is stored into element <code>b[0]</code>, the |
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* next one into <code>b[1]</code>, and so on. The number of bytes read is, |
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* at most, equal to the length of <code>b</code>. 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]</code> through <code>b[</code><i>k</i><code>-1]</code>, |
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* leaving elements <code>b[</code><i>k</i><code>]</code> through |
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* <code>b[b.length-1]</code> unaffected. |
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* |
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* <p> The <code>read(b)</code> method for class <code>InputStream</code> |
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* has the same effect as: <pre><code> read(b, 0, b.length) </code></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</code> if there is no more data because the end of |
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* the stream has been reached. |
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* @exception 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 closed, or |
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* if some other I/O error occurs. |
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* @exception NullPointerException if <code>b</code> is <code>null</code>. |
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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</code> 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</code> 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</code> is zero, then no bytes are read and |
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* <code>0</code> 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</code> is returned; otherwise, at least one |
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* byte is read and stored into <code>b</code>. |
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* |
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* <p> The first byte read is stored into element <code>b[off]</code>, the |
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* next one into <code>b[off+1]</code>, and so on. The number of bytes read |
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* is, at most, equal to <code>len</code>. 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]</code> through <code>b[off+</code><i>k</i><code>-1]</code>, |
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* leaving elements <code>b[off+</code><i>k</i><code>]</code> through |
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* <code>b[off+len-1]</code> unaffected. |
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* |
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* <p> In every case, elements <code>b[0]</code> through |
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* <code>b[off]</code> and elements <code>b[off+len]</code> through |
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* <code>b[b.length-1]</code> are unaffected. |
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* |
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* <p> The <code>read(b,</code> <code>off,</code> <code>len)</code> method |
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* for class <code>InputStream</code> simply calls the method |
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* <code>read()</code> repeatedly. If the first such call results in an |
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* <code>IOException</code>, that exception is returned from the call to |
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* the <code>read(b,</code> <code>off,</code> <code>len)</code> method. If |
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* any subsequent call to <code>read()</code> results in a |
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* <code>IOException</code>, 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</code> 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</code> 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</code> |
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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</code> if there is no more data because the end of |
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* the stream has been reached. |
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* @exception 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, or if |
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* some other I/O error occurs. |
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* @exception NullPointerException If <code>b</code> is <code>null</code>. |
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* @exception IndexOutOfBoundsException If <code>off</code> is negative, |
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* <code>len</code> is negative, or <code>len</code> is greater than |
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* <code>b.length - off</code> |
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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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} catch (IOException ee) { |
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} |
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return i; |
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} |
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/** |
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* The maximum size of array to allocate. |
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* 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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/** |
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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. |
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* |
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* <p> Note that this method is intended for simple cases where it is |
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* convenient to read all bytes into a byte array. It is not intended for |
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* reading input streams with large amounts of data. |
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* |
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* <p> The behavior for the case where the input stream is <i>asynchronously |
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* closed</i>, or the thread interrupted during the read, is highly input |
|
* stream specific, and therefore not specified. |
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* |
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* <p> If an I/O error occurs reading from the input stream, then it may do |
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* so after some, but not all, bytes have been read. Consequently the input |
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* stream may not be at end of stream and may be in an inconsistent state. |
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* It is strongly recommended that the stream be promptly closed if an I/O |
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* error occurs. |
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* |
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* @implSpec |
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* This method invokes {@link #readNBytes(int)} with a length of |
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* {@link Integer#MAX_VALUE}. |
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* |
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* @return a byte array containing the bytes read from this input stream |
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* @throws IOException if an I/O error occurs |
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* @throws OutOfMemoryError if an array of the required size cannot be |
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* allocated. |
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* |
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* @since 9 |
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*/ |
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public byte[] readAllBytes() throws IOException { |
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return readNBytes(Integer.MAX_VALUE); |
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} |
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/** |
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* Reads up to a specified number of bytes from the input stream. This |
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* method blocks until the requested number of bytes have been read, end |
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* of stream is detected, or an exception is thrown. This method does not |
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* close the input stream. |
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* |
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* <p> The length of the returned array equals the number of bytes read |
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* from the stream. If {@code len} is zero, then no bytes are read and |
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* an empty byte array is returned. Otherwise, up to {@code len} bytes |
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* are read from the stream. Fewer than {@code len} bytes may be read if |
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* end of stream is encountered. |
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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. |
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* |
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* <p> Note that this method is intended for simple cases where it is |
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* convenient to read the specified number of bytes into a byte array. The |
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* total amount of memory allocated by this method is proportional to the |
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* number of bytes read from the stream which is bounded by {@code len}. |
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* Therefore, the method may be safely called with very large values of |
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* {@code len} provided sufficient memory is available. |
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* |
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* <p> The behavior for the case where the input stream is <i>asynchronously |
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* closed</i>, or the thread interrupted during the read, is highly input |
|
* stream specific, and therefore not specified. |
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* |
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* <p> If an I/O error occurs reading from the input stream, then it may do |
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* so after some, but not all, bytes have been read. Consequently the input |
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* stream may not be at end of stream and may be in an inconsistent state. |
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* It is strongly recommended that the stream be promptly closed if an I/O |
|
* error occurs. |
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* |
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* @implNote |
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* The number of bytes allocated to read data from this stream and return |
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* the result is bounded by {@code 2*(long)len}, inclusive. |
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* |
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* @param len the maximum number of bytes to read |
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* @return a byte array containing the bytes read from this input stream |
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* @throws IllegalArgumentException if {@code length} is negative |
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* @throws IOException if an I/O error occurs |
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* @throws OutOfMemoryError if an array of the required size cannot be |
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* allocated. |
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* |
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* @since 11 |
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*/ |
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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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List<byte[]> bufs = null; |
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byte[] result = null; |
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int total = 0; |
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int remaining = len; |
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int n; |
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do { |
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byte[] buf = new byte[Math.min(remaining, DEFAULT_BUFFER_SIZE)]; |
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int nread = 0; |
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// read to EOF which may read more or less than buffer size |
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while ((n = read(buf, nread, |
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Math.min(buf.length - nread, remaining))) > 0) { |
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nread += n; |
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remaining -= n; |
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} |
|
if (nread > 0) { |
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if (MAX_BUFFER_SIZE - total < nread) { |
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throw new OutOfMemoryError("Required array size too large"); |
|
} |
|
total += nread; |
|
if (result == null) { |
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result = buf; |
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} else { |
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if (bufs == null) { |
|
bufs = new ArrayList<>(); |
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bufs.add(result); |
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} |
|
bufs.add(buf); |
|
} |
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} |
|
// if the last call to read returned -1 or the number of bytes |
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// requested have been read then break |
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} while (n >= 0 && remaining > 0); |
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if (bufs == null) { |
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if (result == null) { |
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return new byte[0]; |
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} |
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return result.length == total ? |
|
result : Arrays.copyOf(result, total); |
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} |
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result = new byte[total]; |
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int offset = 0; |
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remaining = total; |
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for (byte[] b : bufs) { |
|
int count = Math.min(b.length, remaining); |
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System.arraycopy(b, 0, result, offset, count); |
|
offset += count; |
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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</code> bytes of data from this input |
|
* stream. The <code>skip</code> method may, for a variety of reasons, end |
|
* up skipping over some smaller number of bytes, possibly <code>0</code>. |
|
* This may result from any of a number of conditions; reaching end of file |
|
* before <code>n</code> 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</code> method implementation of this class creates a |
|
* byte array and then repeatedly reads into it until <code>n</code> 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. |
|
* @throws IOException if an I/O error occurs. |
|
*/ |
|
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; |
|
} |
|
/** |
|
* 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. |
|
* @exception 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</code> method of <code>InputStream</code> does |
|
* nothing. |
|
* |
|
* @exception 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</code> method repositions this stream at the last marked |
|
* position so that subsequent reads re-read the same bytes. |
|
* |
|
* <p> The <code>readlimit</code> 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</code> is that, if the method |
|
* <code>markSupported</code> returns <code>true</code>, the stream somehow |
|
* remembers all the bytes read after the call to <code>mark</code> and |
|
* stands ready to supply those same bytes again if and whenever the method |
|
* <code>reset</code> is called. However, the stream is not required to |
|
* remember any data at all if more than <code>readlimit</code> bytes are |
|
* read from the stream before <code>reset</code> is called. |
|
* |
|
* <p> Marking a closed stream should not have any effect on the stream. |
|
* |
|
* <p> The <code>mark</code> method of <code>InputStream</code> 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</code> method was last called on this input stream. |
|
* |
|
* <p> The general contract of <code>reset</code> is: |
|
* |
|
* <ul> |
|
* <li> If the method <code>markSupported</code> returns |
|
* <code>true</code>, then: |
|
* |
|
* <ul><li> If the method <code>mark</code> has not been called since |
|
* the stream was created, or the number of bytes read from the stream |
|
* since <code>mark</code> was last called is larger than the argument |
|
* to <code>mark</code> at that last call, then an |
|
* <code>IOException</code> might be thrown. |
|
* |
|
* <li> If such an <code>IOException</code> 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</code> (or since the start of the |
|
* file, if <code>mark</code> has not been called) will be resupplied |
|
* to subsequent callers of the <code>read</code> method, followed by |
|
* any bytes that otherwise would have been the next input data as of |
|
* the time of the call to <code>reset</code>. </ul> |
|
* |
|
* <li> If the method <code>markSupported</code> returns |
|
* <code>false</code>, then: |
|
* |
|
* <ul><li> The call to <code>reset</code> may throw an |
|
* <code>IOException</code>. |
|
* |
|
* <li> If an <code>IOException</code> 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</code> method depend on the |
|
* particular type of the input stream. </ul></ul> |
|
* |
|
* <p>The method <code>reset</code> for class <code>InputStream</code> |
|
* does nothing except throw an <code>IOException</code>. |
|
* |
|
* @exception 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</code> and |
|
* <code>reset</code> methods. Whether or not <code>mark</code> and |
|
* <code>reset</code> are supported is an invariant property of a |
|
* particular input stream instance. The <code>markSupported</code> method |
|
* of <code>InputStream</code> returns <code>false</code>. |
|
* |
|
* @return <code>true</code> if this stream instance supports the mark |
|
* and reset methods; <code>false</code> 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; |
|
} |
|
} |