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/*
* Copyright (c) 2009, 2017, 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.
*/
/**
* IOUtils: A collection of IO-related public static methods.
*/
package sun.misc;
import java.io.EOFException;
import java.io.IOException;
import java.io.InputStream;
import java.util.Arrays;
public class IOUtils {
/**
* Read up to {@code length} of bytes from {@code in}
* until EOF is detected.
* @param is input stream, must not be null
* @param length number of bytes to read, -1 or Integer.MAX_VALUE means
* read as much as possible
* @param readAll if true, an EOFException will be thrown if not enough
* bytes are read. Ignored when length is -1 or Integer.MAX_VALUE
* @return bytes read
* @throws IOException Any IO error or a premature EOF is detected
*/
public static byte[] readFully(InputStream is, int length, boolean readAll)
throws IOException {
byte[] output = {};
if (length == -1) length = Integer.MAX_VALUE;
int pos = 0;
while (pos < length) {
int bytesToRead;
if (pos >= output.length) { // Only expand when there's no room
bytesToRead = Math.min(length - pos, output.length + 1024);
if (output.length < pos + bytesToRead) {
output = Arrays.copyOf(output, pos + bytesToRead);
}
} else {
bytesToRead = output.length - pos;
}
int cc = is.read(output, pos, bytesToRead);
if (cc < 0) {
if (readAll && length != Integer.MAX_VALUE) {
throw new EOFException("Detect premature EOF");
} else {
if (output.length != pos) {
output = Arrays.copyOf(output, pos);
}
break;
}
}
pos += cc;
}
return output;
}
/**
* Read {@code length} of bytes from {@code in}. An exception is
* thrown if there are not enough bytes in the stream.
*
* @param is input stream, must not be null
* @param length number of bytes to read, must not be negative
* @return bytes read
* @throws IOException if any IO error or a premature EOF is detected, or
* if {@code length} is negative since this length is usually also
* read from {@code is}.
*/
public static byte[] readNBytes(InputStream is, int length) throws IOException {
if (length < 0) {
throw new IOException("length cannot be negative: " + length);
}
return readFully(is, length, true);
}
}
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