author | bpb |
Fri, 07 Mar 2014 13:05:07 -0800 | |
changeset 23334 | 8b590110ed8e |
parent 23010 | 6dadb192ad81 |
child 23742 | c2b6216ef41d |
permissions | -rw-r--r-- |
2 | 1 |
/* |
23010
6dadb192ad81
8029235: Update copyright year to match last edit in jdk8 jdk repository for 2013
lana
parents:
21278
diff
changeset
|
2 |
* Copyright (c) 1995, 2013, Oracle and/or its affiliates. All rights reserved. |
2 | 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 |
|
5506 | 7 |
* published by the Free Software Foundation. Oracle designates this |
2 | 8 |
* particular file as subject to the "Classpath" exception as provided |
5506 | 9 |
* by Oracle in the LICENSE file that accompanied this code. |
2 | 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 |
* |
|
5506 | 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. |
|
2 | 24 |
*/ |
25 |
||
26 |
package sun.misc; |
|
27 |
||
28 |
import java.io.OutputStream; |
|
29 |
import java.io.ByteArrayOutputStream; |
|
30 |
import java.io.InputStream; |
|
31 |
import java.io.PushbackInputStream; |
|
32 |
import java.io.ByteArrayInputStream; |
|
33 |
import java.io.IOException; |
|
34 |
import java.nio.ByteBuffer; |
|
35 |
||
36 |
/** |
|
37 |
* This class defines the decoding half of character encoders. |
|
38 |
* A character decoder is an algorithim for transforming 8 bit |
|
39 |
* binary data that has been encoded into text by a character |
|
40 |
* encoder, back into original binary form. |
|
41 |
* |
|
42 |
* The character encoders, in general, have been structured |
|
43 |
* around a central theme that binary data can be encoded into |
|
44 |
* text that has the form: |
|
45 |
* |
|
46 |
* <pre> |
|
47 |
* [Buffer Prefix] |
|
48 |
* [Line Prefix][encoded data atoms][Line Suffix] |
|
49 |
* [Buffer Suffix] |
|
50 |
* </pre> |
|
51 |
* |
|
52 |
* Of course in the simplest encoding schemes, the buffer has no |
|
53 |
* distinct prefix of suffix, however all have some fixed relationship |
|
54 |
* between the text in an 'atom' and the binary data itself. |
|
55 |
* |
|
56 |
* In the CharacterEncoder and CharacterDecoder classes, one complete |
|
57 |
* chunk of data is referred to as a <i>buffer</i>. Encoded buffers |
|
58 |
* are all text, and decoded buffers (sometimes just referred to as |
|
59 |
* buffers) are binary octets. |
|
60 |
* |
|
61 |
* To create a custom decoder, you must, at a minimum, overide three |
|
62 |
* abstract methods in this class. |
|
63 |
* <DL> |
|
64 |
* <DD>bytesPerAtom which tells the decoder how many bytes to |
|
65 |
* expect from decodeAtom |
|
66 |
* <DD>decodeAtom which decodes the bytes sent to it as text. |
|
67 |
* <DD>bytesPerLine which tells the encoder the maximum number of |
|
68 |
* bytes per line. |
|
69 |
* </DL> |
|
70 |
* |
|
71 |
* In general, the character decoders return error in the form of a |
|
72 |
* CEFormatException. The syntax of the detail string is |
|
73 |
* <pre> |
|
74 |
* DecoderClassName: Error message. |
|
75 |
* </pre> |
|
76 |
* |
|
77 |
* Several useful decoders have already been written and are |
|
78 |
* referenced in the See Also list below. |
|
79 |
* |
|
80 |
* @author Chuck McManis |
|
81 |
* @see CEFormatException |
|
82 |
* @see CharacterEncoder |
|
83 |
* @see UCDecoder |
|
84 |
* @see UUDecoder |
|
85 |
* @see BASE64Decoder |
|
86 |
*/ |
|
87 |
||
88 |
public abstract class CharacterDecoder { |
|
89 |
||
90 |
/** Return the number of bytes per atom of decoding */ |
|
91 |
abstract protected int bytesPerAtom(); |
|
92 |
||
93 |
/** Return the maximum number of bytes that can be encoded per line */ |
|
94 |
abstract protected int bytesPerLine(); |
|
95 |
||
96 |
/** decode the beginning of the buffer, by default this is a NOP. */ |
|
97 |
protected void decodeBufferPrefix(PushbackInputStream aStream, OutputStream bStream) throws IOException { } |
|
98 |
||
99 |
/** decode the buffer suffix, again by default it is a NOP. */ |
|
100 |
protected void decodeBufferSuffix(PushbackInputStream aStream, OutputStream bStream) throws IOException { } |
|
101 |
||
102 |
/** |
|
103 |
* This method should return, if it knows, the number of bytes |
|
104 |
* that will be decoded. Many formats such as uuencoding provide |
|
105 |
* this information. By default we return the maximum bytes that |
|
106 |
* could have been encoded on the line. |
|
107 |
*/ |
|
108 |
protected int decodeLinePrefix(PushbackInputStream aStream, OutputStream bStream) throws IOException { |
|
109 |
return (bytesPerLine()); |
|
110 |
} |
|
111 |
||
112 |
/** |
|
113 |
* This method post processes the line, if there are error detection |
|
114 |
* or correction codes in a line, they are generally processed by |
|
115 |
* this method. The simplest version of this method looks for the |
|
116 |
* (newline) character. |
|
117 |
*/ |
|
118 |
protected void decodeLineSuffix(PushbackInputStream aStream, OutputStream bStream) throws IOException { } |
|
119 |
||
120 |
/** |
|
121 |
* This method does an actual decode. It takes the decoded bytes and |
|
122 |
* writes them to the OutputStream. The integer <i>l</i> tells the |
|
123 |
* method how many bytes are required. This is always <= bytesPerAtom(). |
|
124 |
*/ |
|
125 |
protected void decodeAtom(PushbackInputStream aStream, OutputStream bStream, int l) throws IOException { |
|
126 |
throw new CEStreamExhausted(); |
|
127 |
} |
|
128 |
||
129 |
/** |
|
130 |
* This method works around the bizarre semantics of BufferedInputStream's |
|
131 |
* read method. |
|
132 |
*/ |
|
133 |
protected int readFully(InputStream in, byte buffer[], int offset, int len) |
|
134 |
throws java.io.IOException { |
|
135 |
for (int i = 0; i < len; i++) { |
|
136 |
int q = in.read(); |
|
137 |
if (q == -1) |
|
138 |
return ((i == 0) ? -1 : i); |
|
139 |
buffer[i+offset] = (byte)q; |
|
140 |
} |
|
141 |
return len; |
|
142 |
} |
|
143 |
||
144 |
/** |
|
145 |
* Decode the text from the InputStream and write the decoded |
|
146 |
* octets to the OutputStream. This method runs until the stream |
|
147 |
* is exhausted. |
|
21278 | 148 |
* @exception CEFormatException An error has occurred while decoding |
2 | 149 |
* @exception CEStreamExhausted The input stream is unexpectedly out of data |
150 |
*/ |
|
151 |
public void decodeBuffer(InputStream aStream, OutputStream bStream) throws IOException { |
|
152 |
int i; |
|
153 |
int totalBytes = 0; |
|
154 |
||
155 |
PushbackInputStream ps = new PushbackInputStream (aStream); |
|
156 |
decodeBufferPrefix(ps, bStream); |
|
157 |
while (true) { |
|
158 |
int length; |
|
159 |
||
160 |
try { |
|
161 |
length = decodeLinePrefix(ps, bStream); |
|
162 |
for (i = 0; (i+bytesPerAtom()) < length; i += bytesPerAtom()) { |
|
163 |
decodeAtom(ps, bStream, bytesPerAtom()); |
|
164 |
totalBytes += bytesPerAtom(); |
|
165 |
} |
|
166 |
if ((i + bytesPerAtom()) == length) { |
|
167 |
decodeAtom(ps, bStream, bytesPerAtom()); |
|
168 |
totalBytes += bytesPerAtom(); |
|
169 |
} else { |
|
170 |
decodeAtom(ps, bStream, length - i); |
|
171 |
totalBytes += (length - i); |
|
172 |
} |
|
173 |
decodeLineSuffix(ps, bStream); |
|
174 |
} catch (CEStreamExhausted e) { |
|
175 |
break; |
|
176 |
} |
|
177 |
} |
|
178 |
decodeBufferSuffix(ps, bStream); |
|
179 |
} |
|
180 |
||
181 |
/** |
|
182 |
* Alternate decode interface that takes a String containing the encoded |
|
183 |
* buffer and returns a byte array containing the data. |
|
21278 | 184 |
* @exception CEFormatException An error has occurred while decoding |
2 | 185 |
*/ |
23334
8b590110ed8e
8036848: Fix deprecation warning in sun.misc.CharacterDecoder
bpb
parents:
23010
diff
changeset
|
186 |
public byte[] decodeBuffer(String inputString) throws IOException { |
8b590110ed8e
8036848: Fix deprecation warning in sun.misc.CharacterDecoder
bpb
parents:
23010
diff
changeset
|
187 |
byte inputBuffer[] = inputString.getBytes(); |
8b590110ed8e
8036848: Fix deprecation warning in sun.misc.CharacterDecoder
bpb
parents:
23010
diff
changeset
|
188 |
ByteArrayInputStream inStream = new ByteArrayInputStream(inputBuffer); |
8b590110ed8e
8036848: Fix deprecation warning in sun.misc.CharacterDecoder
bpb
parents:
23010
diff
changeset
|
189 |
ByteArrayOutputStream outStream = new ByteArrayOutputStream(); |
2 | 190 |
decodeBuffer(inStream, outStream); |
23334
8b590110ed8e
8036848: Fix deprecation warning in sun.misc.CharacterDecoder
bpb
parents:
23010
diff
changeset
|
191 |
return outStream.toByteArray(); |
2 | 192 |
} |
193 |
||
194 |
/** |
|
195 |
* Decode the contents of the inputstream into a buffer. |
|
196 |
*/ |
|
23334
8b590110ed8e
8036848: Fix deprecation warning in sun.misc.CharacterDecoder
bpb
parents:
23010
diff
changeset
|
197 |
public byte[] decodeBuffer(InputStream in) throws IOException { |
2 | 198 |
ByteArrayOutputStream outStream = new ByteArrayOutputStream(); |
199 |
decodeBuffer(in, outStream); |
|
23334
8b590110ed8e
8036848: Fix deprecation warning in sun.misc.CharacterDecoder
bpb
parents:
23010
diff
changeset
|
200 |
return outStream.toByteArray(); |
2 | 201 |
} |
202 |
||
203 |
/** |
|
204 |
* Decode the contents of the String into a ByteBuffer. |
|
205 |
*/ |
|
206 |
public ByteBuffer decodeBufferToByteBuffer(String inputString) |
|
207 |
throws IOException { |
|
208 |
return ByteBuffer.wrap(decodeBuffer(inputString)); |
|
209 |
} |
|
210 |
||
211 |
/** |
|
212 |
* Decode the contents of the inputStream into a ByteBuffer. |
|
213 |
*/ |
|
214 |
public ByteBuffer decodeBufferToByteBuffer(InputStream in) |
|
215 |
throws IOException { |
|
216 |
return ByteBuffer.wrap(decodeBuffer(in)); |
|
217 |
} |
|
218 |
} |