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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 }