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/*
* Copyright (c) 1994, 2024, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
package java.io;
import jdk.internal.util.ArraysSupport;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.Objects;
/**
* This abstract class is the superclass of all classes representing
* an input stream of bytes.
*
* <p> Applications that need to define a subclass of {@code InputStream}
* must always provide a method that returns the next byte of input.
*
* @author Arthur van Hoff
* @see java.io.BufferedInputStream
* @see java.io.ByteArrayInputStream
* @see java.io.DataInputStream
* @see java.io.FilterInputStream
* @see java.io.InputStream#read()
* @see java.io.OutputStream
* @see java.io.PushbackInputStream
* @since 1.0
*/
public abstract class InputStream implements Closeable {
// MAX_SKIP_BUFFER_SIZE is used to determine the maximum buffer size to
// use when skipping.
private static final int MAX_SKIP_BUFFER_SIZE = 2048;
private static final int DEFAULT_BUFFER_SIZE = 16384;
/**
* Constructor for subclasses to call.
*/
public InputStream() {}
/**
* Returns a new {@code InputStream} that reads no bytes. The returned
* stream is initially open. The stream is closed by calling the
* {@code close()} method. Subsequent calls to {@code close()} have no
* effect.
*
* <p> While the stream is open, the {@code available()}, {@code read()},
* {@code read(byte[])}, {@code read(byte[], int, int)},
* {@code readAllBytes()}, {@code readNBytes(byte[], int, int)},
* {@code readNBytes(int)}, {@code skip(long)}, {@code skipNBytes(long)},
* and {@code transferTo()} methods all behave as if end of stream has been
* reached. After the stream has been closed, these methods all throw
* {@code IOException}.
*
* <p> The {@code markSupported()} method returns {@code false}. The
* {@code mark()} method does nothing, and the {@code reset()} method
* throws {@code IOException}.
*
* @return an {@code InputStream} which contains no bytes
*
* @since 11
*/
public static InputStream nullInputStream() {
return new InputStream() {
private volatile boolean closed;
private void ensureOpen() throws IOException {
if (closed) {
throw new IOException("Stream closed");
}
}
@Override
public int available () throws IOException {
ensureOpen();
return 0;
}
@Override
public int read() throws IOException {
ensureOpen();
return -1;
}
@Override
public int read(byte[] b, int off, int len) throws IOException {
Objects.checkFromIndexSize(off, len, b.length);
if (len == 0) {
return 0;
}
ensureOpen();
return -1;
}
@Override
public byte[] readAllBytes() throws IOException {
ensureOpen();
return new byte[0];
}
@Override
public int readNBytes(byte[] b, int off, int len)
throws IOException {
Objects.checkFromIndexSize(off, len, b.length);
ensureOpen();
return 0;
}
@Override
public byte[] readNBytes(int len) throws IOException {
if (len < 0) {
throw new IllegalArgumentException("len < 0");
}
ensureOpen();
return new byte[0];
}
@Override
public long skip(long n) throws IOException {
ensureOpen();
return 0L;
}
@Override
public void skipNBytes(long n) throws IOException {
ensureOpen();
if (n > 0) {
throw new EOFException();
}
}
@Override
public long transferTo(OutputStream out) throws IOException {
Objects.requireNonNull(out);
ensureOpen();
return 0L;
}
@Override
public void close() throws IOException {
closed = true;
}
};
}
/**
* Reads the next byte of data from the input stream. The value byte is
* returned as an {@code int} in the range {@code 0} to
* {@code 255}. If no byte is available because the end of the stream
* has been reached, the value {@code -1} is returned. This method
* blocks until input data is available, the end of the stream is detected,
* or an exception is thrown.
*
* @return the next byte of data, or {@code -1} if the end of the
* stream is reached.
* @throws IOException if an I/O error occurs.
*/
public abstract int read() throws IOException;
/**
* Reads some number of bytes from the input stream and stores them into
* the buffer array {@code b}. The number of bytes actually read is
* returned as an integer. This method blocks until input data is
* available, end of file is detected, or an exception is thrown.
*
* <p> If the length of {@code b} is zero, then no bytes are read and
* {@code 0} is returned; otherwise, there is an attempt to read at
* least one byte. If no byte is available because the stream is at the
* end of the file, the value {@code -1} is returned; otherwise, at
* least one byte is read and stored into {@code b}.
*
* <p> The first byte read is stored into element {@code b[0]}, the
* next one into {@code b[1]}, and so on. The number of bytes read is,
* at most, equal to the length of {@code b}. Let <i>k</i> be the
* number of bytes actually read; these bytes will be stored in elements
* {@code b[0]} through {@code b[}<i>k</i>{@code -1]},
* leaving elements {@code b[}<i>k</i>{@code ]} through
* {@code b[b.length-1]} unaffected.
*
* @implSpec
* The {@code read(b)} method for class {@code InputStream}
* has the same effect as:
* {@snippet lang=java :
* read(b, 0, b.length)
* }
*
* @param b the buffer into which the data is read.
* @return the total number of bytes read into the buffer, or
* {@code -1} if there is no more data because the end of
* the stream has been reached.
* @throws IOException If the first byte cannot be read for any reason
* other than the end of the file, if the input stream has been
* closed, or if some other I/O error occurs.
* @throws NullPointerException if {@code b} is {@code null}.
* @see java.io.InputStream#read(byte[], int, int)
*/
public int read(byte[] b) throws IOException {
return read(b, 0, b.length);
}
/**
* Reads up to {@code len} bytes of data from the input stream into
* an array of bytes. An attempt is made to read as many as
* {@code len} bytes, but a smaller number may be read.
* The number of bytes actually read is returned as an integer.
*
* <p> This method blocks until input data is available, end of file is
* detected, or an exception is thrown.
*
* <p> If {@code len} is zero, then no bytes are read and
* {@code 0} is returned; otherwise, there is an attempt to read at
* least one byte. If no byte is available because the stream is at end of
* file, the value {@code -1} is returned; otherwise, at least one
* byte is read and stored into {@code b}.
*
* <p> The first byte read is stored into element {@code b[off]}, the
* next one into {@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> In every case, elements {@code b[0]} through
* {@code b[off-1]} and elements {@code b[off+len]} through
* {@code b[b.length-1]} are unaffected.
*
* @implSpec
* The {@code read(b, off, len)} method
* for class {@code InputStream} simply calls the method
* {@code read()} repeatedly. If the first such call results in an
* {@code IOException}, that exception is returned from the call to
* the {@code read(b,} {@code off,} {@code len)} method. If
* any subsequent call to {@code read()} results in a
* {@code IOException}, the exception is caught and treated as if it
* were end of file; the bytes read up to that point are stored into
* {@code b} and the number of bytes read before the exception
* occurred is returned. The default implementation of this method blocks
* until the requested amount of input data {@code len} has been read,
* end of file is detected, or an exception is thrown. Subclasses are
* encouraged to provide a more efficient implementation of this method.
*
* @param b the buffer into which the data is read.
* @param off the start offset in array {@code b}
* at which the data is written.
* @param len the maximum number of bytes to read.
* @return the total number of bytes read into the buffer, or
* {@code -1} if there is no more data because the end of
* the stream has been reached.
* @throws IOException If the first byte cannot be read for any reason
* other than end of file, or if the input stream has been closed,
* or if some other 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}
* @see java.io.InputStream#read()
*/
public int read(byte[] b, int off, int len) throws IOException {
Objects.checkFromIndexSize(off, len, b.length);
if (len == 0) {
return 0;
}
int c = read();
if (c == -1) {
return -1;
}
b[off] = (byte)c;
int i = 1;
try {
for (; i < len ; i++) {
c = read();
if (c == -1) {
break;
}
b[off + i] = (byte)c;
}
} catch (IOException ee) {
}
return i;
}
/**
* The maximum size of array to allocate
*/
private static final int MAX_BUFFER_SIZE = ArraysSupport.SOFT_MAX_ARRAY_LENGTH;
/**
* Reads all remaining bytes from the input stream. This method blocks until
* all remaining bytes have been read and end of stream is detected, or an
* exception is thrown. This method does not close the input stream.
*
* <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 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.
*
* @implSpec
* 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.
*
* @implSpec
* The {@code available} method of {@code InputStream} always returns
* {@code 0}.
*
* @apiNote
* 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.
*
* @implSpec
* 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.
*
* @implSpec
* 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 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>
*
* @implSpec
* 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 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.
*
* @implSpec
* 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 the total number of bytes transferred is greater than {@linkplain
* Long#MAX_VALUE}, then {@code Long.MAX_VALUE} will be returned.
* <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);
if (transferred < Long.MAX_VALUE) {
try {
transferred = Math.addExact(transferred, read);
} catch (ArithmeticException ignore) {
transferred = Long.MAX_VALUE;
}
}
}
return transferred;
}
}