    001/*
    002 * Licensed to the Apache Software Foundation (ASF) under one or more
    003 * contributor license agreements.  See the NOTICE file distributed with
    004 * this work for additional information regarding copyright ownership.
    005 * The ASF licenses this file to You under the Apache License, Version 2.0
    006 * (the "License"); you may not use this file except in compliance with
    007 * the License.  You may obtain a copy of the License at
    008 *
    009 *      http://www.apache.org/licenses/LICENSE-2.0
    010 *
    011 * Unless required by applicable law or agreed to in writing, software
    012 * distributed under the License is distributed on an "AS IS" BASIS,
    013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    014 * See the License for the specific language governing permissions and
    015 * limitations under the License.
    016 */
    017package org.apache.commons.io;
    018
    019import java.io.IOException;
    020import java.io.OutputStream;
    021import java.io.OutputStreamWriter;
    022import java.nio.charset.Charset;
    023import java.util.Objects;
    024
    025import org.apache.commons.io.output.CloseShieldOutputStream;
    026
    027/**
    028 * Dumps data in hexadecimal format.
    029 * <p>
    030 * Provides a single function to take an array of bytes and display it
    031 * in hexadecimal form.
    032 * </p>
    033 * <p>
    034 * Provenance: POI.
    035 * </p>
    036 */
    037public class HexDump {
    038
    039    /**
    040     * The line-separator (initializes to "line.separator" system property).
    041     *
    042     * @deprecated Use {@link System#lineSeparator()}.
    043     */
    044    @Deprecated
    045    public static final String EOL = System.lineSeparator();
    046
    047    private static final char[] HEX_CODES =
    048            {
    049                '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
    050                'A', 'B', 'C', 'D', 'E', 'F'
    051            };
    052
    053    private static final int[] SHIFTS =
    054            {
    055                28, 24, 20, 16, 12, 8, 4, 0
    056            };
    057
    058    /**
    059     * Dumps an array of bytes to an Appendable. The output is formatted
    060     * for human inspection, with a hexadecimal offset followed by the
    061     * hexadecimal values of the next 16 bytes of data and the printable ASCII
    062     * characters (if any) that those bytes represent printed per each line
    063     * of output.
    064     *
    065     * @param data  the byte array to be dumped
    066     * @param appendable  the Appendable to which the data is to be written
    067     *
    068     * @throws IOException is thrown if anything goes wrong writing
    069     *         the data to appendable
    070     * @throws NullPointerException if the output appendable is null
    071     *
    072     * @since 2.12.0
    073     */
    074    public static void dump(final byte[] data, final Appendable appendable)
    075            throws IOException {
    076        dump(data, 0, appendable, 0, data.length);
    077    }
    078
    079    /**
    080     * Dumps an array of bytes to an Appendable. The output is formatted
    081     * for human inspection, with a hexadecimal offset followed by the
    082     * hexadecimal values of the next 16 bytes of data and the printable ASCII
    083     * characters (if any) that those bytes represent printed per each line
    084     * of output.
    085     * <p>
    086     * The offset argument specifies the start offset of the data array
    087     * within a larger entity like a file or an incoming stream. For example,
    088     * if the data array contains the third kibibyte of a file, then the
    089     * offset argument should be set to 2048. The offset value printed
    090     * at the beginning of each line indicates where in that larger entity
    091     * the first byte on that line is located.
    092     * </p>
    093     *
    094     * @param data  the byte array to be dumped
    095     * @param offset  offset of the byte array within a larger entity
    096     * @param appendable  the Appendable to which the data is to be written
    097     * @param index initial index into the byte array
    098     * @param length number of bytes to dump from the array
    099     *
    100     * @throws IOException is thrown if anything goes wrong writing
    101     *         the data to appendable
    102     * @throws ArrayIndexOutOfBoundsException if the index or length is
    103     *         outside the data array's bounds
    104     * @throws NullPointerException if the output appendable is null
    105     *
    106     * @since 2.12.0
    107     */
    108    public static void dump(final byte[] data, final long offset,
    109                            final Appendable appendable, final int index,
    110                            final int length)
    111            throws IOException, ArrayIndexOutOfBoundsException {
    112        Objects.requireNonNull(appendable, "appendable");
    113        if (index < 0 || index >= data.length) {
    114            throw new ArrayIndexOutOfBoundsException(
    115                    "illegal index: " + index + " into array of length "
    116                    + data.length);
    117        }
    118        long display_offset = offset + index;
    119        final StringBuilder buffer = new StringBuilder(74);
    120
    121        // TODO Use Objects.checkFromIndexSize(index, length, data.length) when upgrading to JDK9
    122        if (length < 0 || index + length > data.length) {
    123            throw new ArrayIndexOutOfBoundsException(String.format("Range [%s, %<s + %s) out of bounds for length %s", index, length, data.length));
    124        }
    125
    126        final int endIndex = index + length;
    127
    128        for (int j = index; j < endIndex; j += 16) {
    129            int chars_read = endIndex - j;
    130
    131            if (chars_read > 16) {
    132                chars_read = 16;
    133            }
    134            dump(buffer, display_offset).append(' ');
    135            for (int k = 0; k < 16; k++) {
    136                if (k < chars_read) {
    137                    dump(buffer, data[k + j]);
    138                } else {
    139                    buffer.append("  ");
    140                }
    141                buffer.append(' ');
    142            }
    143            for (int k = 0; k < chars_read; k++) {
    144                if (data[k + j] >= ' ' && data[k + j] < 127) {
    145                    buffer.append((char) data[k + j]);
    146                } else {
    147                    buffer.append('.');
    148                }
    149            }
    150            buffer.append(System.lineSeparator());
    151            appendable.append(buffer);
    152            buffer.setLength(0);
    153            display_offset += chars_read;
    154        }
    155    }
    156
    157    /**
    158     * Dumps an array of bytes to an OutputStream. The output is formatted
    159     * for human inspection, with a hexadecimal offset followed by the
    160     * hexadecimal values of the next 16 bytes of data and the printable ASCII
    161     * characters (if any) that those bytes represent printed per each line
    162     * of output.
    163     * <p>
    164     * The offset argument specifies the start offset of the data array
    165     * within a larger entity like a file or an incoming stream. For example,
    166     * if the data array contains the third kibibyte of a file, then the
    167     * offset argument should be set to 2048. The offset value printed
    168     * at the beginning of each line indicates where in that larger entity
    169     * the first byte on that line is located.
    170     * </p>
    171     * <p>
    172     * All bytes between the given index (inclusive) and the end of the
    173     * data array are dumped.
    174     * </p>
    175     *
    176     * @param data  the byte array to be dumped
    177     * @param offset  offset of the byte array within a larger entity
    178     * @param stream  the OutputStream to which the data is to be
    179     *               written
    180     * @param index initial index into the byte array
    181     *
    182     * @throws IOException is thrown if anything goes wrong writing
    183     *         the data to stream
    184     * @throws ArrayIndexOutOfBoundsException if the index is
    185     *         outside the data array's bounds
    186     * @throws NullPointerException if the output stream is null
    187     */
    188    @SuppressWarnings("resource") // Caller closes stream
    189    public static void dump(final byte[] data, final long offset,
    190                            final OutputStream stream, final int index)
    191            throws IOException, ArrayIndexOutOfBoundsException {
    192        Objects.requireNonNull(stream, "stream");
    193
    194        try (OutputStreamWriter out = new OutputStreamWriter(CloseShieldOutputStream.wrap(stream), Charset.defaultCharset())) {
    195            dump(data, offset, out, index, data.length - index);
    196        }
    197    }
    198
    199    /**
    200     * Dumps a byte value into a StringBuilder.
    201     *
    202     * @param _cbuffer the StringBuilder to dump the value in
    203     * @param value  the byte value to be dumped
    204     * @return StringBuilder containing the dumped value.
    205     */
    206    private static StringBuilder dump(final StringBuilder _cbuffer, final byte value) {
    207        for (int j = 0; j < 2; j++) {
    208            _cbuffer.append(HEX_CODES[value >> SHIFTS[j + 6] & 15]);
    209        }
    210        return _cbuffer;
    211    }
    212
    213    /**
    214     * Dumps a long value into a StringBuilder.
    215     *
    216     * @param _lbuffer the StringBuilder to dump the value in
    217     * @param value  the long value to be dumped
    218     * @return StringBuilder containing the dumped value.
    219     */
    220    private static StringBuilder dump(final StringBuilder _lbuffer, final long value) {
    221        for (int j = 0; j < 8; j++) {
    222            _lbuffer
    223                    .append(HEX_CODES[(int) (value >> SHIFTS[j]) & 15]);
    224        }
    225        return _lbuffer;
    226    }
    227
    228    /**
    229     * Instances should NOT be constructed in standard programming.
    230     */
    231    public HexDump() {
    232    }
    233
    234}