IOUtils.java
/*
* 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.commons.compress.utils;
import java.io.ByteArrayOutputStream;
import java.io.Closeable;
import java.io.EOFException;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.nio.ByteBuffer;
import java.nio.channels.ReadableByteChannel;
import java.nio.file.Files;
import java.nio.file.LinkOption;
/**
* Utility functions
*
* @Immutable (has mutable data but it is write-only)
*/
public final class IOUtils {
private static final int COPY_BUF_SIZE = 8024;
private static final int SKIP_BUF_SIZE = 4096;
/**
* Empty array of type {@link LinkOption}.
*
* @since 1.21
*/
public static final LinkOption[] EMPTY_LINK_OPTIONS = {};
// This buffer does not need to be synchronized because it is write only; the contents are ignored
// Does not affect Immutability
private static final byte[] SKIP_BUF = new byte[SKIP_BUF_SIZE];
/**
* Closes the given Closeable and swallows any IOException that may occur.
*
* @param c Closeable to close, can be null
* @since 1.7
*/
public static void closeQuietly(final Closeable c) {
if (c != null) {
try {
c.close();
} catch (final IOException ignored) { // NOPMD NOSONAR
}
}
}
/**
* Copies the source file to the given output stream.
*
* @param sourceFile The file to read.
* @param outputStream The output stream to write.
* @throws IOException if an I/O error occurs when reading or writing.
* @since 1.21
*/
public static void copy(final File sourceFile, final OutputStream outputStream) throws IOException {
Files.copy(sourceFile.toPath(), outputStream);
}
/**
* Copies the content of a InputStream into an OutputStream. Uses a default buffer size of 8024 bytes.
*
* @param input the InputStream to copy
* @param output the target, may be null to simulate output to dev/null on Linux and NUL on Windows
* @return the number of bytes copied
* @throws IOException if an error occurs
*/
public static long copy(final InputStream input, final OutputStream output) throws IOException {
return copy(input, output, COPY_BUF_SIZE);
}
/**
* Copies the content of a InputStream into an OutputStream
*
* @param input the InputStream to copy
* @param output the target, may be null to simulate output to dev/null on Linux and NUL on Windows
* @param bufferSize the buffer size to use, must be bigger than 0
* @return the number of bytes copied
* @throws IOException if an error occurs
* @throws IllegalArgumentException if bufferSize is smaller than or equal to 0
*/
public static long copy(final InputStream input, final OutputStream output, final int bufferSize) throws IOException {
if (bufferSize < 1) {
throw new IllegalArgumentException("bufferSize must be bigger than 0");
}
final byte[] buffer = new byte[bufferSize];
int n = 0;
long count = 0;
while (-1 != (n = input.read(buffer))) {
if (output != null) {
output.write(buffer, 0, n);
}
count += n;
}
return count;
}
/**
* Copies part of the content of a InputStream into an OutputStream. Uses a default buffer size of 8024 bytes.
*
* @param input the InputStream to copy
* @param output the target Stream
* @param len maximum amount of bytes to copy
* @return the number of bytes copied
* @throws IOException if an error occurs
* @since 1.21
*/
public static long copyRange(final InputStream input, final long len, final OutputStream output) throws IOException {
return copyRange(input, len, output, COPY_BUF_SIZE);
}
/**
* Copies part of the content of a InputStream into an OutputStream
*
* @param input the InputStream to copy
* @param len maximum amount of bytes to copy
* @param output the target, may be null to simulate output to dev/null on Linux and NUL on Windows
* @param bufferSize the buffer size to use, must be bigger than 0
* @return the number of bytes copied
* @throws IOException if an error occurs
* @throws IllegalArgumentException if bufferSize is smaller than or equal to 0
* @since 1.21
*/
public static long copyRange(final InputStream input, final long len, final OutputStream output, final int bufferSize) throws IOException {
if (bufferSize < 1) {
throw new IllegalArgumentException("bufferSize must be bigger than 0");
}
final byte[] buffer = new byte[(int) Math.min(bufferSize, Math.max(0, len))];
int n = 0;
long count = 0;
while (count < len && -1 != (n = input.read(buffer, 0, (int) Math.min(len - count, buffer.length)))) {
if (output != null) {
output.write(buffer, 0, n);
}
count += n;
}
return count;
}
/**
* Reads as much from the file as possible to fill the given array.
*
* <p>
* This method may invoke read repeatedly to fill the array and only read less bytes than the length of the array if the end of the stream has been reached.
* </p>
*
* @param file file to read
* @param array buffer to fill
* @return the number of bytes actually read
* @throws IOException on error
* @since 1.20
*/
public static int read(final File file, final byte[] array) throws IOException {
try (InputStream inputStream = Files.newInputStream(file.toPath())) {
return readFully(inputStream, array, 0, array.length);
}
}
/**
* Reads as much from input as possible to fill the given array.
*
* <p>
* This method may invoke read repeatedly to fill the array and only read less bytes than the length of the array if the end of the stream has been reached.
* </p>
*
* @param input stream to read from
* @param array buffer to fill
* @return the number of bytes actually read
* @throws IOException on error
*/
public static int readFully(final InputStream input, final byte[] array) throws IOException {
return readFully(input, array, 0, array.length);
}
// toByteArray(InputStream) copied from:
// commons/proper/io/trunk/src/main/java/org/apache/commons/io/IOUtils.java?revision=1428941
// January 8th, 2013
//
// Assuming our copy() works just as well as theirs! :-)
/**
* Reads as much from input as possible to fill the given array with the given amount of bytes.
*
* <p>
* This method may invoke read repeatedly to read the bytes and only read less bytes than the requested length if the end of the stream has been reached.
* </p>
*
* @param input stream to read from
* @param array buffer to fill
* @param offset offset into the buffer to start filling at
* @param len of bytes to read
* @return the number of bytes actually read
* @throws IOException if an I/O error has occurred
*/
public static int readFully(final InputStream input, final byte[] array, final int offset, final int len) throws IOException {
if (len < 0 || offset < 0 || len + offset > array.length || len + offset < 0) {
throw new IndexOutOfBoundsException();
}
int count = 0, x = 0;
while (count != len) {
x = input.read(array, offset + count, len - count);
if (x == -1) {
break;
}
count += x;
}
return count;
}
/**
* Reads {@code b.remaining()} bytes from the given channel starting at the current channel's position.
*
* <p>
* This method reads repeatedly from the channel until the requested number of bytes are read. This method blocks until the requested number of bytes are
* read, the end of the channel is detected, or an exception is thrown.
* </p>
*
* @param channel the channel to read from
* @param byteBuffer the buffer into which the data is read.
* @throws IOException - if an I/O error occurs.
* @throws EOFException - if the channel reaches the end before reading all the bytes.
*/
public static void readFully(final ReadableByteChannel channel, final ByteBuffer byteBuffer) throws IOException {
final int expectedLength = byteBuffer.remaining();
int read = 0;
while (read < expectedLength) {
final int readNow = channel.read(byteBuffer);
if (readNow <= 0) {
break;
}
read += readNow;
}
if (read < expectedLength) {
throw new EOFException();
}
}
/**
* Gets part of the contents of an {@code InputStream} as a {@code byte[]}.
*
* @param input the {@code InputStream} to read from
* @param len maximum amount of bytes to copy
* @return the requested byte array
* @throws NullPointerException if the input is null
* @throws IOException if an I/O error occurs
* @since 1.21
*/
public static byte[] readRange(final InputStream input, final int len) throws IOException {
final ByteArrayOutputStream output = new ByteArrayOutputStream();
copyRange(input, len, output);
return output.toByteArray();
}
/**
* Gets part of the contents of an {@code ReadableByteChannel} as a {@code byte[]}.
*
* @param input the {@code ReadableByteChannel} to read from
* @param len maximum amount of bytes to copy
* @return the requested byte array
* @throws NullPointerException if the input is null
* @throws IOException if an I/O error occurs
* @since 1.21
*/
public static byte[] readRange(final ReadableByteChannel input, final int len) throws IOException {
final ByteArrayOutputStream output = new ByteArrayOutputStream();
final ByteBuffer b = ByteBuffer.allocate(Math.min(len, COPY_BUF_SIZE));
int read = 0;
while (read < len) {
// Make sure we never read more than len bytes
b.limit(Math.min(len - read, b.capacity()));
final int readNow = input.read(b);
if (readNow <= 0) {
break;
}
output.write(b.array(), 0, readNow);
b.rewind();
read += readNow;
}
return output.toByteArray();
}
/**
* Skips the given number of bytes by repeatedly invoking skip on the given input stream if necessary.
*
* <p>
* In a case where the stream's skip() method returns 0 before the requested number of bytes has been skip this implementation will fall back to using the
* read() method.
* </p>
*
* <p>
* This method will only skip less than the requested number of bytes if the end of the input stream has been reached.
* </p>
*
* @param input stream to skip bytes in
* @param numToSkip the number of bytes to skip
* @return the number of bytes actually skipped
* @throws IOException on error
*/
public static long skip(final InputStream input, long numToSkip) throws IOException {
final long available = numToSkip;
while (numToSkip > 0) {
final long skipped = input.skip(numToSkip);
if (skipped == 0) {
break;
}
numToSkip -= skipped;
}
while (numToSkip > 0) {
final int read = readFully(input, SKIP_BUF, 0, (int) Math.min(numToSkip, SKIP_BUF_SIZE));
if (read < 1) {
break;
}
numToSkip -= read;
}
return available - numToSkip;
}
/**
* Gets the contents of an {@code InputStream} as a {@code byte[]}.
* <p>
* This method buffers the input internally, so there is no need to use a {@code BufferedInputStream}.
*
* @param input the {@code InputStream} to read from
* @return the requested byte array
* @throws NullPointerException if the input is null
* @throws IOException if an I/O error occurs
* @since 1.5
*/
public static byte[] toByteArray(final InputStream input) throws IOException {
final ByteArrayOutputStream output = new ByteArrayOutputStream();
copy(input, output);
return output.toByteArray();
}
/** Private constructor to prevent instantiation of this utility class. */
private IOUtils() {
}
}