Source code

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 builder 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 builder, final byte value) {
207        for (int j = 0; j < 2; j++) {
208            builder.append(HEX_CODES[value >> SHIFTS[j + 6] & 15]);
209        }
210        return builder;
211    }
212
213    /**
214     * Dumps a long value into a StringBuilder.
215     *
216     * @param builder 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 builder, final long value) {
221        for (int j = 0; j < 8; j++) {
222            builder.append(HEX_CODES[(int) (value >> SHIFTS[j]) & 15]);
223        }
224        return builder;
225    }
226
227    /**
228     * Instances should NOT be constructed in standard programming.
229     */
230    public HexDump() {
231    }
232
233}