1 /*

     2  * Copyright (c) 1995, 1997, Oracle and/or its affiliates. All rights reserved.

     3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

     4  *

     5  * This code is free software; you can redistribute it and/or modify it

     6  * under the terms of the GNU General Public License version 2 only, as

     7  * published by the Free Software Foundation.  Oracle designates this

     8  * particular file as subject to the "Classpath" exception as provided

     9  * by Oracle in the LICENSE file that accompanied this code.

    10  *

    11  * This code is distributed in the hope that it will be useful, but WITHOUT

    12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

    13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

    14  * version 2 for more details (a copy is included in the LICENSE file that

    15  * accompanied this code).

    16  *

    17  * You should have received a copy of the GNU General Public License version

    18  * 2 along with this work; if not, write to the Free Software Foundation,

    19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

    20  *

    21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

    22  * or visit www.oracle.com if you need additional information or have any

    23  * questions.

    24  */

    25 

    26 

    27 package sun.misc;

    28 import java.io.PrintStream;

    29 import java.io.OutputStream;

    30 import java.io.IOException;

    31 

    32 /**

    33  * This class encodes a buffer into the classic: "Hexadecimal Dump" format of

    34  * the past. It is useful for analyzing the contents of binary buffers.

    35  * The format produced is as follows:

    36  * <pre>

    37  * xxxx: 00 11 22 33 44 55 66 77   88 99 aa bb cc dd ee ff ................

    38  * </pre>

    39  * Where xxxx is the offset into the buffer in 16 byte chunks, followed

    40  * by ascii coded hexadecimal bytes followed by the ASCII representation of

    41  * the bytes or '.' if they are not valid bytes.

    42  *

    43  * @author      Chuck McManis

    44  */

    45 

    46 public class HexDumpEncoder extends CharacterEncoder {

    47 

    48     private int offset;

    49     private int thisLineLength;

    50     private int currentByte;

    51     private byte thisLine[] = new byte[16];

    52 

    53     static void hexDigit(PrintStream p, byte x) {

    54         char c;

    55 

    56         c = (char) ((x >> 4) & 0xf);

    57         if (c > 9)

    58             c = (char) ((c-10) + 'A');

    59         else

    60             c = (char)(c + '0');

    61         p.write(c);

    62         c = (char) (x & 0xf);

    63         if (c > 9)

    64             c = (char)((c-10) + 'A');

    65         else

    66             c = (char)(c + '0');

    67         p.write(c);

    68     }

    69 

    70     protected int bytesPerAtom() {

    71         return (1);

    72     }

    73 

    74     protected int bytesPerLine() {

    75         return (16);

    76     }

    77 

    78     protected void encodeBufferPrefix(OutputStream o) throws IOException {

    79         offset = 0;

    80         super.encodeBufferPrefix(o);

    81     }

    82 

    83     protected void encodeLinePrefix(OutputStream o, int len) throws IOException {

    84         hexDigit(pStream, (byte)((offset >>> 8) & 0xff));

    85         hexDigit(pStream, (byte)(offset & 0xff));

    86         pStream.print(": ");

    87         currentByte = 0;

    88         thisLineLength = len;

    89     }

    90 

    91     protected void encodeAtom(OutputStream o, byte buf[], int off, int len) throws IOException {

    92         thisLine[currentByte] = buf[off];

    93         hexDigit(pStream, buf[off]);

    94         pStream.print(" ");

    95         currentByte++;

    96         if (currentByte == 8)

    97             pStream.print("  ");

    98     }

    99 

   100     protected void encodeLineSuffix(OutputStream o) throws IOException {

   101         if (thisLineLength < 16) {

   102             for (int i = thisLineLength; i < 16; i++) {

   103                 pStream.print("   ");

   104                 if (i == 7)

   105                     pStream.print("  ");

   106             }

   107         }

   108         pStream.print(" ");

   109         for (int i = 0; i < thisLineLength; i++) {

   110             if ((thisLine[i] < ' ') || (thisLine[i] > 'z')) {

   111                 pStream.print(".");

   112             } else {

   113                 pStream.write(thisLine[i]);

   114             }

   115         }

   116         pStream.println();

   117         offset += thisLineLength;

   118     }

   119 

   120 }