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 */ 017 package org.apache.commons.io; 018 019 import java.io.IOException; 020 import java.io.OutputStream; 021 022 /** 023 * Dumps data in hexadecimal format. 024 * <p> 025 * Provides a single function to take an array of bytes and display it 026 * in hexadecimal form. 027 * <p> 028 * Origin of code: POI. 029 * 030 * @author Scott Sanders 031 * @author Marc Johnson 032 * @version $Id: HexDump.java 596667 2007-11-20 13:50:14Z niallp $ 033 */ 034 public class HexDump { 035 036 /** 037 * Instances should NOT be constructed in standard programming. 038 */ 039 public HexDump() { 040 super(); 041 } 042 043 /** 044 * Dump an array of bytes to an OutputStream. 045 * 046 * @param data the byte array to be dumped 047 * @param offset its offset, whatever that might mean 048 * @param stream the OutputStream to which the data is to be 049 * written 050 * @param index initial index into the byte array 051 * 052 * @throws IOException is thrown if anything goes wrong writing 053 * the data to stream 054 * @throws ArrayIndexOutOfBoundsException if the index is 055 * outside the data array's bounds 056 * @throws IllegalArgumentException if the output stream is null 057 */ 058 059 public static void dump(byte[] data, long offset, 060 OutputStream stream, int index) 061 throws IOException, ArrayIndexOutOfBoundsException, 062 IllegalArgumentException { 063 064 if ((index < 0) || (index >= data.length)) { 065 throw new ArrayIndexOutOfBoundsException( 066 "illegal index: " + index + " into array of length " 067 + data.length); 068 } 069 if (stream == null) { 070 throw new IllegalArgumentException("cannot write to nullstream"); 071 } 072 long display_offset = offset + index; 073 StringBuffer buffer = new StringBuffer(74); 074 075 for (int j = index; j < data.length; j += 16) { 076 int chars_read = data.length - j; 077 078 if (chars_read > 16) { 079 chars_read = 16; 080 } 081 dump(buffer, display_offset).append(' '); 082 for (int k = 0; k < 16; k++) { 083 if (k < chars_read) { 084 dump(buffer, data[k + j]); 085 } else { 086 buffer.append(" "); 087 } 088 buffer.append(' '); 089 } 090 for (int k = 0; k < chars_read; k++) { 091 if ((data[k + j] >= ' ') && (data[k + j] < 127)) { 092 buffer.append((char) data[k + j]); 093 } else { 094 buffer.append('.'); 095 } 096 } 097 buffer.append(EOL); 098 stream.write(buffer.toString().getBytes()); 099 stream.flush(); 100 buffer.setLength(0); 101 display_offset += chars_read; 102 } 103 } 104 105 /** 106 * The line-separator (initializes to "line.separator" system property. 107 */ 108 public static final String EOL = 109 System.getProperty("line.separator"); 110 private static final char[] _hexcodes = 111 { 112 '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 113 'A', 'B', 'C', 'D', 'E', 'F' 114 }; 115 private static final int[] _shifts = 116 { 117 28, 24, 20, 16, 12, 8, 4, 0 118 }; 119 120 /** 121 * Dump a long value into a StringBuffer. 122 * 123 * @param _lbuffer the StringBuffer to dump the value in 124 * @param value the long value to be dumped 125 * @return StringBuffer containing the dumped value. 126 */ 127 private static StringBuffer dump(StringBuffer _lbuffer, long value) { 128 for (int j = 0; j < 8; j++) { 129 _lbuffer 130 .append(_hexcodes[((int) (value >> _shifts[j])) & 15]); 131 } 132 return _lbuffer; 133 } 134 135 /** 136 * Dump a byte value into a StringBuffer. 137 * 138 * @param _cbuffer the StringBuffer to dump the value in 139 * @param value the byte value to be dumped 140 * @return StringBuffer containing the dumped value. 141 */ 142 private static StringBuffer dump(StringBuffer _cbuffer, byte value) { 143 for (int j = 0; j < 2; j++) { 144 _cbuffer.append(_hexcodes[(value >> _shifts[j + 6]) & 15]); 145 } 146 return _cbuffer; 147 } 148 149 }