001/*
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements.  See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership.  The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License.  You may obtain a copy of the License at
009 *
010 * http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing,
013 * software distributed under the License is distributed on an
014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
015 * KIND, either express or implied.  See the License for the
016 * specific language governing permissions and limitations
017 * under the License.
018 */
019package org.apache.commons.compress.utils;
020
021import java.io.ByteArrayOutputStream;
022import java.io.Closeable;
023import java.io.EOFException;
024import java.io.File;
025import java.io.FileInputStream;
026import java.io.IOException;
027import java.io.InputStream;
028import java.io.OutputStream;
029import java.nio.ByteBuffer;
030import java.nio.channels.ReadableByteChannel;
031
032/**
033 * Utility functions
034 * @Immutable (has mutable data but it is write-only)
035 */
036public final class IOUtils {
037
038    private static final int COPY_BUF_SIZE = 8024;
039    private static final int SKIP_BUF_SIZE = 4096;
040
041    // This buffer does not need to be synchronised because it is write only; the contents are ignored
042    // Does not affect Immutability
043    private static final byte[] SKIP_BUF = new byte[SKIP_BUF_SIZE];
044
045    /** Private constructor to prevent instantiation of this utility class. */
046    private IOUtils(){
047    }
048
049    /**
050     * Copies the content of a InputStream into an OutputStream.
051     * Uses a default buffer size of 8024 bytes.
052     *
053     * @param input
054     *            the InputStream to copy
055     * @param output
056     *            the target Stream
057     * @return the number of bytes copied
058     * @throws IOException
059     *             if an error occurs
060     */
061    public static long copy(final InputStream input, final OutputStream output) throws IOException {
062        return copy(input, output, COPY_BUF_SIZE);
063    }
064
065    /**
066     * Copies the content of a InputStream into an OutputStream
067     *
068     * @param input
069     *            the InputStream to copy
070     * @param output
071     *            the target Stream
072     * @param buffersize
073     *            the buffer size to use, must be bigger than 0
074     * @return the number of bytes copied
075     * @throws IOException
076     *             if an error occurs
077     * @throws IllegalArgumentException
078     *             if buffersize is smaller than or equal to 0
079     */
080    public static long copy(final InputStream input, final OutputStream output, final int buffersize) throws IOException {
081        if (buffersize < 1) {
082            throw new IllegalArgumentException("buffersize must be bigger than 0");
083        }
084        final byte[] buffer = new byte[buffersize];
085        int n = 0;
086        long count=0;
087        while (-1 != (n = input.read(buffer))) {
088            output.write(buffer, 0, n);
089            count += n;
090        }
091        return count;
092    }
093
094    /**
095     * Skips the given number of bytes by repeatedly invoking skip on
096     * the given input stream if necessary.
097     *
098     * <p>In a case where the stream's skip() method returns 0 before
099     * the requested number of bytes has been skip this implementation
100     * will fall back to using the read() method.</p>
101     *
102     * <p>This method will only skip less than the requested number of
103     * bytes if the end of the input stream has been reached.</p>
104     *
105     * @param input stream to skip bytes in
106     * @param numToSkip the number of bytes to skip
107     * @return the number of bytes actually skipped
108     * @throws IOException on error
109     */
110    public static long skip(final InputStream input, long numToSkip) throws IOException {
111        final long available = numToSkip;
112        while (numToSkip > 0) {
113            final long skipped = input.skip(numToSkip);
114            if (skipped == 0) {
115                break;
116            }
117            numToSkip -= skipped;
118        }
119
120        while (numToSkip > 0) {
121            final int read = readFully(input, SKIP_BUF, 0,
122                                 (int) Math.min(numToSkip, SKIP_BUF_SIZE));
123            if (read < 1) {
124                break;
125            }
126            numToSkip -= read;
127        }
128        return available - numToSkip;
129    }
130
131    /**
132     * Reads as much from the file as possible to fill the given array.
133     *
134     * <p>This method may invoke read repeatedly to fill the array and
135     * only read less bytes than the length of the array if the end of
136     * the stream has been reached.</p>
137     *
138     * @param file file to read
139     * @param array buffer to fill
140     * @return the number of bytes actually read
141     * @throws IOException on error
142     * @since 1.20
143     */
144    public static int read(final File file, final byte[] array) throws IOException {
145        try (FileInputStream inputStream = new FileInputStream(file)) {
146            return readFully(inputStream, array, 0, array.length);
147        }
148    }
149
150    /**
151     * Reads as much from input as possible to fill the given array.
152     *
153     * <p>This method may invoke read repeatedly to fill the array and
154     * only read less bytes than the length of the array if the end of
155     * the stream has been reached.</p>
156     *
157     * @param input stream to read from
158     * @param array buffer to fill
159     * @return the number of bytes actually read
160     * @throws IOException on error
161     */
162    public static int readFully(final InputStream input, final byte[] array) throws IOException {
163        return readFully(input, array, 0, array.length);
164    }
165
166    /**
167     * Reads as much from input as possible to fill the given array
168     * with the given amount of bytes.
169     *
170     * <p>This method may invoke read repeatedly to read the bytes and
171     * only read less bytes than the requested length if the end of
172     * the stream has been reached.</p>
173     *
174     * @param input stream to read from
175     * @param array buffer to fill
176     * @param offset offset into the buffer to start filling at
177     * @param len of bytes to read
178     * @return the number of bytes actually read
179     * @throws IOException
180     *             if an I/O error has occurred
181     */
182    public static int readFully(final InputStream input, final byte[] array, final int offset, final int len)
183        throws IOException {
184        if (len < 0 || offset < 0 || len + offset > array.length) {
185            throw new IndexOutOfBoundsException();
186        }
187        int count = 0, x = 0;
188        while (count != len) {
189            x = input.read(array, offset + count, len - count);
190            if (x == -1) {
191                break;
192            }
193            count += x;
194        }
195        return count;
196    }
197
198    /**
199     * Reads {@code b.remaining()} bytes from the given channel
200     * starting at the current channel's position.
201     *
202     * <p>This method reads repeatedly from the channel until the
203     * requested number of bytes are read. This method blocks until
204     * the requested number of bytes are read, the end of the channel
205     * is detected, or an exception is thrown.</p>
206     *
207     * @param channel the channel to read from
208     * @param b the buffer into which the data is read.
209     * @throws IOException - if an I/O error occurs.
210     * @throws EOFException - if the channel reaches the end before reading all the bytes.
211     */
212    public static void readFully(ReadableByteChannel channel, ByteBuffer b) throws IOException {
213        final int expectedLength = b.remaining();
214        int read = 0;
215        while (read < expectedLength) {
216            int readNow = channel.read(b);
217            if (readNow <= 0) {
218                break;
219            }
220            read += readNow;
221        }
222        if (read < expectedLength) {
223            throw new EOFException();
224        }
225    }
226
227    // toByteArray(InputStream) copied from:
228    // commons/proper/io/trunk/src/main/java/org/apache/commons/io/IOUtils.java?revision=1428941
229    // January 8th, 2013
230    //
231    // Assuming our copy() works just as well as theirs!  :-)
232
233    /**
234     * Gets the contents of an <code>InputStream</code> as a <code>byte[]</code>.
235     * <p>
236     * This method buffers the input internally, so there is no need to use a
237     * <code>BufferedInputStream</code>.
238     *
239     * @param input  the <code>InputStream</code> to read from
240     * @return the requested byte array
241     * @throws NullPointerException if the input is null
242     * @throws IOException if an I/O error occurs
243     * @since 1.5
244     */
245    public static byte[] toByteArray(final InputStream input) throws IOException {
246        final ByteArrayOutputStream output = new ByteArrayOutputStream();
247        copy(input, output);
248        return output.toByteArray();
249    }
250
251    /**
252     * Closes the given Closeable and swallows any IOException that may occur.
253     * @param c Closeable to close, can be null
254     * @since 1.7
255     */
256    public static void closeQuietly(final Closeable c) {
257        if (c != null) {
258            try {
259                c.close();
260            } catch (final IOException ignored) { // NOPMD NOSONAR
261            }
262        }
263    }
264}