    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.IOException;
    026import java.io.InputStream;
    027import java.io.OutputStream;
    028import java.nio.ByteBuffer;
    029import java.nio.channels.ReadableByteChannel;
    030import java.nio.file.Files;
    031import java.nio.file.LinkOption;
    032
    033/**
    034 * Utility functions
    035 * @Immutable (has mutable data but it is write-only)
    036 */
    037public final class IOUtils {
    038
    039    private static final int COPY_BUF_SIZE = 8024;
    040    private static final int SKIP_BUF_SIZE = 4096;
    041
    042    /**
    043     * Empty array of of type {@link LinkOption}.
    044     *
    045     * @since 1.21
    046     */
    047    public static final LinkOption[] EMPTY_LINK_OPTIONS = {};
    048
    049    // This buffer does not need to be synchronized because it is write only; the contents are ignored
    050    // Does not affect Immutability
    051    private static final byte[] SKIP_BUF = new byte[SKIP_BUF_SIZE];
    052
    053    /** Private constructor to prevent instantiation of this utility class. */
    054    private IOUtils(){
    055    }
    056
    057    /**
    058     * Copies the content of a InputStream into an OutputStream.
    059     * Uses a default buffer size of 8024 bytes.
    060     *
    061     * @param input
    062     *            the InputStream to copy
    063     * @param output
    064     *            the target Stream
    065     * @return the number of bytes copied
    066     * @throws IOException
    067     *             if an error occurs
    068     */
    069    public static long copy(final InputStream input, final OutputStream output) throws IOException {
    070        return copy(input, output, COPY_BUF_SIZE);
    071    }
    072
    073    /**
    074     * Copies the content of a InputStream into an OutputStream
    075     *
    076     * @param input
    077     *            the InputStream to copy
    078     * @param output
    079     *            the target Stream
    080     * @param buffersize
    081     *            the buffer size to use, must be bigger than 0
    082     * @return the number of bytes copied
    083     * @throws IOException
    084     *             if an error occurs
    085     * @throws IllegalArgumentException
    086     *             if buffersize is smaller than or equal to 0
    087     */
    088    public static long copy(final InputStream input, final OutputStream output, final int buffersize) throws IOException {
    089        if (buffersize < 1) {
    090            throw new IllegalArgumentException("buffersize must be bigger than 0");
    091        }
    092        final byte[] buffer = new byte[buffersize];
    093        int n = 0;
    094        long count=0;
    095        while (-1 != (n = input.read(buffer))) {
    096            output.write(buffer, 0, n);
    097            count += n;
    098        }
    099        return count;
    100    }
    101
    102    /**
    103     * Skips the given number of bytes by repeatedly invoking skip on
    104     * the given input stream if necessary.
    105     *
    106     * <p>In a case where the stream's skip() method returns 0 before
    107     * the requested number of bytes has been skip this implementation
    108     * will fall back to using the read() method.</p>
    109     *
    110     * <p>This method will only skip less than the requested number of
    111     * bytes if the end of the input stream has been reached.</p>
    112     *
    113     * @param input stream to skip bytes in
    114     * @param numToSkip the number of bytes to skip
    115     * @return the number of bytes actually skipped
    116     * @throws IOException on error
    117     */
    118    public static long skip(final InputStream input, long numToSkip) throws IOException {
    119        final long available = numToSkip;
    120        while (numToSkip > 0) {
    121            final long skipped = input.skip(numToSkip);
    122            if (skipped == 0) {
    123                break;
    124            }
    125            numToSkip -= skipped;
    126        }
    127
    128        while (numToSkip > 0) {
    129            final int read = readFully(input, SKIP_BUF, 0,
    130                                 (int) Math.min(numToSkip, SKIP_BUF_SIZE));
    131            if (read < 1) {
    132                break;
    133            }
    134            numToSkip -= read;
    135        }
    136        return available - numToSkip;
    137    }
    138
    139    /**
    140     * Reads as much from the file as possible to fill the given array.
    141     *
    142     * <p>This method may invoke read repeatedly to fill the array and
    143     * only read less bytes than the length of the array if the end of
    144     * the stream has been reached.</p>
    145     *
    146     * @param file file to read
    147     * @param array buffer to fill
    148     * @return the number of bytes actually read
    149     * @throws IOException on error
    150     * @since 1.20
    151     */
    152    public static int read(final File file, final byte[] array) throws IOException {
    153        try (InputStream inputStream = Files.newInputStream(file.toPath())) {
    154            return readFully(inputStream, array, 0, array.length);
    155        }
    156    }
    157
    158    /**
    159     * Reads as much from input as possible to fill the given array.
    160     *
    161     * <p>This method may invoke read repeatedly to fill the array and
    162     * only read less bytes than the length of the array if the end of
    163     * the stream has been reached.</p>
    164     *
    165     * @param input stream to read from
    166     * @param array buffer to fill
    167     * @return the number of bytes actually read
    168     * @throws IOException on error
    169     */
    170    public static int readFully(final InputStream input, final byte[] array) throws IOException {
    171        return readFully(input, array, 0, array.length);
    172    }
    173
    174    /**
    175     * Reads as much from input as possible to fill the given array
    176     * with the given amount of bytes.
    177     *
    178     * <p>This method may invoke read repeatedly to read the bytes and
    179     * only read less bytes than the requested length if the end of
    180     * the stream has been reached.</p>
    181     *
    182     * @param input stream to read from
    183     * @param array buffer to fill
    184     * @param offset offset into the buffer to start filling at
    185     * @param len of bytes to read
    186     * @return the number of bytes actually read
    187     * @throws IOException
    188     *             if an I/O error has occurred
    189     */
    190    public static int readFully(final InputStream input, final byte[] array, final int offset, final int len)
    191        throws IOException {
    192        if (len < 0 || offset < 0 || len + offset > array.length || len + offset < 0) {
    193            throw new IndexOutOfBoundsException();
    194        }
    195        int count = 0, x = 0;
    196        while (count != len) {
    197            x = input.read(array, offset + count, len - count);
    198            if (x == -1) {
    199                break;
    200            }
    201            count += x;
    202        }
    203        return count;
    204    }
    205
    206    /**
    207     * Reads {@code b.remaining()} bytes from the given channel
    208     * starting at the current channel's position.
    209     *
    210     * <p>This method reads repeatedly from the channel until the
    211     * requested number of bytes are read. This method blocks until
    212     * the requested number of bytes are read, the end of the channel
    213     * is detected, or an exception is thrown.</p>
    214     *
    215     * @param channel the channel to read from
    216     * @param b the buffer into which the data is read.
    217     * @throws IOException - if an I/O error occurs.
    218     * @throws EOFException - if the channel reaches the end before reading all the bytes.
    219     */
    220    public static void readFully(final ReadableByteChannel channel, final ByteBuffer b) throws IOException {
    221        final int expectedLength = b.remaining();
    222        int read = 0;
    223        while (read < expectedLength) {
    224            final int readNow = channel.read(b);
    225            if (readNow <= 0) {
    226                break;
    227            }
    228            read += readNow;
    229        }
    230        if (read < expectedLength) {
    231            throw new EOFException();
    232        }
    233    }
    234
    235    // toByteArray(InputStream) copied from:
    236    // commons/proper/io/trunk/src/main/java/org/apache/commons/io/IOUtils.java?revision=1428941
    237    // January 8th, 2013
    238    //
    239    // Assuming our copy() works just as well as theirs!  :-)
    240
    241    /**
    242     * Gets the contents of an <code>InputStream</code> as a <code>byte[]</code>.
    243     * <p>
    244     * This method buffers the input internally, so there is no need to use a
    245     * <code>BufferedInputStream</code>.
    246     *
    247     * @param input  the <code>InputStream</code> to read from
    248     * @return the requested byte array
    249     * @throws NullPointerException if the input is null
    250     * @throws IOException if an I/O error occurs
    251     * @since 1.5
    252     */
    253    public static byte[] toByteArray(final InputStream input) throws IOException {
    254        final ByteArrayOutputStream output = new ByteArrayOutputStream();
    255        copy(input, output);
    256        return output.toByteArray();
    257    }
    258
    259    /**
    260     * Closes the given Closeable and swallows any IOException that may occur.
    261     * @param c Closeable to close, can be null
    262     * @since 1.7
    263     */
    264    public static void closeQuietly(final Closeable c) {
    265        if (c != null) {
    266            try {
    267                c.close();
    268            } catch (final IOException ignored) { // NOPMD NOSONAR
    269            }
    270        }
    271    }
    272
    273    /**
    274     * Copies the source file to the given output stream.
    275     * @param sourceFile The file to read.
    276     * @param outputStream The output stream to write.
    277     * @throws IOException if an I/O error occurs when reading or writing.
    278     * @since 1.21
    279     */
    280    public static void copy(final File sourceFile, final OutputStream outputStream) throws IOException {
    281        Files.copy(sourceFile.toPath(), outputStream);
    282    }
    283
    284    /**
    285     * Copies part of the content of a InputStream into an OutputStream.
    286     * Uses a default buffer size of 8024 bytes.
    287     *
    288     * @param input
    289     *            the InputStream to copy
    290     * @param output
    291     *            the target Stream
    292     * @param len
    293     *            maximum amount of bytes to copy
    294     * @return the number of bytes copied
    295     * @throws IOException
    296     *             if an error occurs
    297     * @since 1.21
    298     */
    299    public static long copyRange(final InputStream input, final long len, final OutputStream output)
    300        throws IOException {
    301        return copyRange(input, len, output, COPY_BUF_SIZE);
    302    }
    303
    304    /**
    305     * Copies part of the content of a InputStream into an OutputStream
    306     *
    307     * @param input
    308     *            the InputStream to copy
    309     * @param len
    310     *            maximum amount of bytes to copy
    311     * @param output
    312     *            the target Stream
    313     * @param buffersize
    314     *            the buffer size to use, must be bigger than 0
    315     * @return the number of bytes copied
    316     * @throws IOException
    317     *             if an error occurs
    318     * @throws IllegalArgumentException
    319     *             if buffersize is smaller than or equal to 0
    320     * @since 1.21
    321     */
    322    public static long copyRange(final InputStream input, final long len, final OutputStream output,
    323        final int buffersize) throws IOException {
    324        if (buffersize < 1) {
    325            throw new IllegalArgumentException("buffersize must be bigger than 0");
    326        }
    327        final byte[] buffer = new byte[(int) Math.min(buffersize, len)];
    328        int n = 0;
    329        long count = 0;
    330        while (count < len && -1 != (n = input.read(buffer, 0, (int) Math.min(len - count, buffer.length)))) {
    331            output.write(buffer, 0, n);
    332            count += n;
    333        }
    334        return count;
    335    }
    336
    337    /**
    338     * Gets part of the contents of an <code>InputStream</code> as a <code>byte[]</code>.
    339     *
    340     * @param input  the <code>InputStream</code> to read from
    341     * @param len
    342     *            maximum amount of bytes to copy
    343     * @return the requested byte array
    344     * @throws NullPointerException if the input is null
    345     * @throws IOException if an I/O error occurs
    346     * @since 1.21
    347     */
    348    public static byte[] readRange(final InputStream input, final int len) throws IOException {
    349        final ByteArrayOutputStream output = new ByteArrayOutputStream();
    350        copyRange(input, len, output);
    351        return output.toByteArray();
    352    }
    353
    354    /**
    355     * Gets part of the contents of an <code>ReadableByteChannel</code> as a <code>byte[]</code>.
    356     *
    357     * @param input  the <code>ReadableByteChannel</code> to read from
    358     * @param len
    359     *            maximum amount of bytes to copy
    360     * @return the requested byte array
    361     * @throws NullPointerException if the input is null
    362     * @throws IOException if an I/O error occurs
    363     * @since 1.21
    364     */
    365    public static byte[] readRange(final ReadableByteChannel input, final int len) throws IOException {
    366        final ByteArrayOutputStream output = new ByteArrayOutputStream();
    367        final ByteBuffer b = ByteBuffer.allocate(Math.min(len, COPY_BUF_SIZE));
    368        int read = 0;
    369        while (read < len) {
    370            final int readNow = input.read(b);
    371            if (readNow <= 0) {
    372                break;
    373            }
    374            output.write(b.array(), 0, readNow);
    375            b.rewind();
    376            read += readNow;
    377        }
    378        return output.toByteArray();
    379    }
    380
    381}