001 /*
002 * Copyright (c) Andrey Kuznetsov. All Rights Reserved.
003 *
004 * http://uio.imagero.com
005 *
006 * Redistribution and use in source and binary forms, with or without
007 * modification, are permitted provided that the following conditions are met:
008 *
009 * o Redistributions of source code must retain the above copyright notice,
010 * this list of conditions and the following disclaimer.
011 *
012 * o Redistributions in binary form must reproduce the above copyright notice,
013 * this list of conditions and the following disclaimer in the documentation
014 * and/or other materials provided with the distribution.
015 *
016 * o Neither the name of Andrey Kuznetsov nor the names of
017 * its contributors may be used to endorse or promote products derived
018 * from this software without specific prior written permission.
019 *
020 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
021 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
022 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
023 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
024 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
025 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
026 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
027 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
028 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
029 * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
030 * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
031 */
032
033 package com.imagero.uio.io;
034
035 import java.io.FilterInputStream;
036 import java.io.IOException;
037 import java.io.InputStream;
038
039 /**
040 * @author Andrey Kuznetsov
041 */
042 public class HexInputStream extends FilterInputStream {
043
044 private static final char encodeTable[] = {
045 '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F'
046 };
047
048 public static final int decodeTable [] = new int[0x100];
049
050 static {
051 for (int i = 0; i < decodeTable.length; i++) {
052 decodeTable[i] = -1;
053 }
054 for (int j = 0; j < encodeTable.length; j++) {
055 decodeTable[encodeTable[j]] = j;
056 }
057 }
058
059 boolean finished;
060
061 byte[] buffer = new byte[80];
062 int count;
063 int pos;
064
065 public HexInputStream(InputStream in) {
066 super(in);
067 }
068
069 public int read() throws IOException {
070 if (pos >= count) {
071 if (finished) {
072 return -1;
073 }
074 else {
075 fillBuffer();
076 }
077 }
078 if (pos < count) {
079 return buffer[pos++] & 0xFF;
080 }
081 return -1;
082 }
083
084 protected void fillBuffer() throws IOException {
085 int k = 0;
086 try {
087 for (; k < buffer.length; k++) {
088 int b0 = in.read();
089 if (b0 == 13 || b0 == 10) {
090 k--;
091 continue;
092 }
093 if (b0 == '>') {
094 k++;
095 finished = true;
096 break;
097 }
098 int b1 = in.read();
099 int d0 = decodeTable[b0];
100 int d1 = decodeTable[b1];
101 if (d0 == -1 || d1 == -1) {
102 k--;
103 continue;
104 }
105 buffer[k] = (byte) (d0 * 16 + d1);
106 }
107 }
108 catch (Throwable ex) {
109 // ex.printStackTrace();
110 System.err.println(ex.getMessage());
111 }
112 count = k;
113 pos = 0;
114 }
115
116 public long skip(long n) throws IOException {
117 long i = 0;
118 for (; i < n; i++) {
119 int a = read();
120 if (a == -1) {
121 break;
122 }
123 }
124 return i;
125 }
126
127 public int read(byte b[]) throws IOException {
128 return read(b, 0, b.length);
129 }
130
131 public int read(byte b[], int off, int len) throws IOException {
132 if (b == null) {
133 return (int) skip(len);
134 }
135 if (len <= 0) {
136 return 0;
137 }
138 int i = 0;
139 try {
140 for (; i < len; i++) {
141 int a = read();
142 if (a == -1) {
143 break;
144 }
145 b[i] = (byte) a;
146 }
147 }
148 catch (IOException ex) {
149 }
150 return i == 0 ? -1 : i;
151 }
152 }