org.apache.commons.io.HexDump Maven / Gradle / Ivy
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/*
* 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.io;
import java.io.IOException;
import java.io.OutputStream;
import java.nio.charset.Charset;
/**
* Dumps data in hexadecimal format.
*
* Provides a single function to take an array of bytes and display it
* in hexadecimal form.
*
* Origin of code: POI.
*
*/
public class HexDump {
/**
* Instances should NOT be constructed in standard programming.
*/
public HexDump() {
super();
}
/**
* Dump an array of bytes to an OutputStream. The output is formatted
* for human inspection, with a hexadecimal offset followed by the
* hexadecimal values of the next 16 bytes of data and the printable ASCII
* characters (if any) that those bytes represent printed per each line
* of output.
*
* The offset argument specifies the start offset of the data array
* within a larger entity like a file or an incoming stream. For example,
* if the data array contains the third kibibyte of a file, then the
* offset argument should be set to 2048. The offset value printed
* at the beginning of each line indicates where in that larger entity
* the first byte on that line is located.
*
* All bytes between the given index (inclusive) and the end of the
* data array are dumped.
*
* @param data the byte array to be dumped
* @param offset offset of the byte array within a larger entity
* @param stream the OutputStream to which the data is to be
* written
* @param index initial index into the byte array
*
* @throws IOException is thrown if anything goes wrong writing
* the data to stream
* @throws ArrayIndexOutOfBoundsException if the index is
* outside the data array's bounds
* @throws IllegalArgumentException if the output stream is null
*/
public static void dump(final byte[] data, final long offset,
final OutputStream stream, final int index)
throws IOException, ArrayIndexOutOfBoundsException,
IllegalArgumentException {
if (index < 0 || index >= data.length) {
throw new ArrayIndexOutOfBoundsException(
"illegal index: " + index + " into array of length "
+ data.length);
}
if (stream == null) {
throw new IllegalArgumentException("cannot write to nullstream");
}
long display_offset = offset + index;
final StringBuilder buffer = new StringBuilder(74);
for (int j = index; j < data.length; j += 16) {
int chars_read = data.length - j;
if (chars_read > 16) {
chars_read = 16;
}
dump(buffer, display_offset).append(' ');
for (int k = 0; k < 16; k++) {
if (k < chars_read) {
dump(buffer, data[k + j]);
} else {
buffer.append(" ");
}
buffer.append(' ');
}
for (int k = 0; k < chars_read; k++) {
if (data[k + j] >= ' ' && data[k + j] < 127) {
buffer.append((char) data[k + j]);
} else {
buffer.append('.');
}
}
buffer.append(EOL);
// make explicit the dependency on the default encoding
stream.write(buffer.toString().getBytes(Charset.defaultCharset()));
stream.flush();
buffer.setLength(0);
display_offset += chars_read;
}
}
/**
* The line-separator (initializes to "line.separator" system property.
*/
public static final String EOL =
System.getProperty("line.separator");
private static final char[] _hexcodes =
{
'0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
'A', 'B', 'C', 'D', 'E', 'F'
};
private static final int[] _shifts =
{
28, 24, 20, 16, 12, 8, 4, 0
};
/**
* Dump a long value into a StringBuilder.
*
* @param _lbuffer the StringBuilder to dump the value in
* @param value the long value to be dumped
* @return StringBuilder containing the dumped value.
*/
private static StringBuilder dump(final StringBuilder _lbuffer, final long value) {
for (int j = 0; j < 8; j++) {
_lbuffer
.append(_hexcodes[(int) (value >> _shifts[j]) & 15]);
}
return _lbuffer;
}
/**
* Dump a byte value into a StringBuilder.
*
* @param _cbuffer the StringBuilder to dump the value in
* @param value the byte value to be dumped
* @return StringBuilder containing the dumped value.
*/
private static StringBuilder dump(final StringBuilder _cbuffer, final byte value) {
for (int j = 0; j < 2; j++) {
_cbuffer.append(_hexcodes[value >> _shifts[j + 6] & 15]);
}
return _cbuffer;
}
}