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- /* ====================================================================
- Licensed to the Apache Software Foundation (ASF) under one or more
- contributor license agreements. See the NOTICE file distributed with
- this work for additional information regarding copyright ownership.
- The ASF licenses this file to You under the Apache License, Version 2.0
- (the "License"); you may not use this file except in compliance with
- the License. You may obtain a copy of the License at
-
- http://www.apache.org/licenses/LICENSE-2.0
-
- Unless required by applicable law or agreed to in writing, software
- distributed under the License is distributed on an "AS IS" BASIS,
- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- See the License for the specific language governing permissions and
- limitations under the License.
- ==================================================================== */
-
- package org.apache.poi.util;
-
- import java.io.ByteArrayOutputStream;
- import java.io.IOException;
- import java.io.InputStream;
- import java.io.OutputStream;
- import java.nio.ByteBuffer;
- import java.nio.channels.ReadableByteChannel;
- import java.util.zip.CRC32;
- import java.util.zip.Checksum;
-
- public final class IOUtils {
- private IOUtils() {
- // no instances of this class
- }
-
- /**
- * Reads all the data from the input stream, and returns the bytes read.
- */
- public static byte[] toByteArray(InputStream stream) throws IOException {
- ByteArrayOutputStream baos = new ByteArrayOutputStream();
-
- byte[] buffer = new byte[4096];
- int read = 0;
- while (read != -1) {
- read = stream.read(buffer);
- if (read > 0) {
- baos.write(buffer, 0, read);
- }
- }
-
- return baos.toByteArray();
- }
-
- /**
- * Returns an array (that shouldn't be written to!) of the
- * ByteBuffer. Will be of the requested length, or possibly
- * longer if that's easier.
- */
- public static byte[] toByteArray(ByteBuffer buffer, int length) {
- if(buffer.hasArray() && buffer.arrayOffset() == 0) {
- // The backing array should work out fine for us
- return buffer.array();
- }
-
- byte[] data = new byte[length];
- buffer.get(data);
- return data;
- }
-
- /**
- * Helper method, just calls <tt>readFully(in, b, 0, b.length)</tt>
- */
- public static int readFully(InputStream in, byte[] b) throws IOException {
- return readFully(in, b, 0, b.length);
- }
-
- /**
- * Same as the normal <tt>in.read(b, off, len)</tt>, but tries to ensure
- * that the entire len number of bytes is read.
- * <p>
- * If the end of file is reached before any bytes are read, returns -1. If
- * the end of the file is reached after some bytes are read, returns the
- * number of bytes read. If the end of the file isn't reached before len
- * bytes have been read, will return len bytes.
- */
- public static int readFully(InputStream in, byte[] b, int off, int len) throws IOException {
- int total = 0;
- while (true) {
- int got = in.read(b, off + total, len - total);
- if (got < 0) {
- return (total == 0) ? -1 : total;
- }
- total += got;
- if (total == len) {
- return total;
- }
- }
- }
-
- /**
- * Same as the normal <tt>channel.read(b)</tt>, but tries to ensure
- * that the entire len number of bytes is read.
- * <p>
- * If the end of file is reached before any bytes are read, returns -1. If
- * the end of the file is reached after some bytes are read, returns the
- * number of bytes read. If the end of the file isn't reached before len
- * bytes have been read, will return len bytes.
- */
- public static int readFully(ReadableByteChannel channel, ByteBuffer b) throws IOException {
- int total = 0;
- while (true) {
- int got = channel.read(b);
- if (got < 0) {
- return (total == 0) ? -1 : total;
- }
- total += got;
- if (total == b.capacity() || b.position() == b.capacity()) {
- return total;
- }
- }
- }
-
- /**
- * Copies all the data from the given InputStream to the OutputStream. It
- * leaves both streams open, so you will still need to close them once done.
- */
- public static void copy(InputStream inp, OutputStream out) throws IOException {
- byte[] buff = new byte[4096];
- int count;
- while ((count = inp.read(buff)) != -1) {
- if (count > 0) {
- out.write(buff, 0, count);
- }
- }
- }
-
- public static long calculateChecksum(byte[] data) {
- Checksum sum = new CRC32();
- sum.update(data, 0, data.length);
- return sum.getValue();
- }
- }
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