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36 package org.columba.ristretto.coder;
37
38 import java.io.FilterInputStream  ;
39 import java.io.IOException ;
40 import java.io.InputStream ;
41 import java.nio.ByteBuffer ;
42 import java.nio.CharBuffer ;
43 import java.nio.charset.CharacterCodingException ;
44 import java.nio.charset.Charset ;
45 import java.nio.charset.CharsetDecoder ;
46 import java.nio.charset.CharsetEncoder ;
47 import java.nio.charset.CoderResult ;
48 import java.nio.charset.CodingErrorAction ;
49 import java.util.Hashtable ;
50
51
56 public class FallbackCharsetDecoderInputStream extends FilterInputStream {
57
58 private Charset charset;
59 private CharsetDecoder decoder;
60 private ByteBuffer inBytes;
61 private CharBuffer outChars;
62
63 private static Hashtable fallbackTable = initFallBackTable();
64
65
71 public FallbackCharsetDecoderInputStream(InputStream arg0, Charset charset) {
72 super(arg0);
73 this.charset = charset;
74 initDecoder();
75
76 inBytes = ByteBuffer.allocate(5);
77 outChars = CharBuffer.allocate(1);
78 }
79
80 private static Hashtable initFallBackTable() {
81 Hashtable table = new Hashtable ();
82
83 table.put(Charset.forName("iso-8859-15"), Charset.forName("windows-1252"));
84 table.put(Charset.forName("iso-8859-1"), Charset.forName("windows-1252"));
85 table.put(Charset.forName("us-ascii"), Charset.forName("windows-1252"));
86
87 return table;
88 }
89
90
96 public static void addFallback(Charset original, Charset fallback) {
97 fallbackTable.put(original, fallback);
98 }
99
100
107 private int decodeNextChar() throws IOException {
108 CoderResult result;
109 int read;
110
111
112 inBytes.clear();
113 inBytes.limit(1);
114
115 read = in.read();
116 if( read == -1) return -1;
117 inBytes.put( 0, (byte) read );
118
119 outChars.clear();
120 result = decoder.decode(inBytes, outChars, in.available() == 0);
121
122
123 if( outChars.position() == 0 ) {
125 read = in.read();
126 if( read == -1) return -1;
127 inBytes.limit(inBytes.limit()+1);
128 inBytes.put(inBytes.limit()-1,(byte) read);
129
130 outChars.clear();
131 result = decoder.decode(inBytes, outChars, in.available() == 0);
132 }
133
134 ByteBuffer test = charset.encode(outChars);
135 while( test.capacity() == 0 && fallback()) {
136 inBytes.rewind();
137 outChars.clear();
138 result = decoder.decode(inBytes, outChars, in.available() == 0);
139 test = charset.encode(outChars);
140 }
141
142 return outChars.position();
143 }
144
145
146 private boolean fallback() {
147 if( fallbackTable.containsKey(charset)) {
148 this.charset = (Charset )fallbackTable.get(charset);
149 initDecoder();
150
151 return true;
152 }
153
154 return false;
155 }
156
157 private void initDecoder() {
158 decoder = charset.newDecoder().onMalformedInput(CodingErrorAction.REPLACE).onUnmappableCharacter(CodingErrorAction.REPLACE);
159 }
160
161
162
165 public int read() throws IOException {
166 if( decodeNextChar() == -1) return -1;
167
168 return outChars.get(0);
169 }
170
171
174 public int read(byte[] arg0, int arg1, int arg2) throws IOException {
175 int next;
176 for( int i=0; i<arg2; i++) {
177 next = read();
178 if( next == -1 ) {
179 if( i == 0 ) {
180 return -1;
181 } else {
182 return i;
183 }
184 }
185 arg0[arg1+i] = (byte) next;
186 }
187 return arg2;
188 }
189
190
191 }
192 |
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