1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
|
/* ByteCharset.java -- Abstract class for generic 1-byte encodings.
Copyright (C) 2005 Free Software Foundation, Inc.
This file is part of GNU Classpath.
GNU Classpath is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.
GNU Classpath is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU General Public License
along with GNU Classpath; see the file COPYING. If not, write to the
Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301 USA.
Linking this library statically or dynamically with other modules is
making a combined work based on this library. Thus, the terms and
conditions of the GNU General Public License cover the whole
combination.
As a special exception, the copyright holders of this library give you
permission to link this library with independent modules to produce an
executable, regardless of the license terms of these independent
modules, and to copy and distribute the resulting executable under
terms of your choice, provided that you also meet, for each linked
independent module, the terms and conditions of the license of that
module. An independent module is a module which is not derived from
or based on this library. If you modify this library, you may extend
this exception to your version of the library, but you are not
obligated to do so. If you do not wish to do so, delete this
exception statement from your version. */
package gnu.java.nio.charset;
import java.nio.ByteBuffer;
import java.nio.CharBuffer;
import java.nio.charset.Charset;
import java.nio.charset.CharsetDecoder;
import java.nio.charset.CharsetEncoder;
import java.nio.charset.CoderResult;
/**
* A generic encoding framework for single-byte encodings,
* utilizing a look-up table.
*
* This replaces the gnu.java.io.EncoderEightBitLookup class,
* created by Aron Renn.
*
* @author Sven de Marothy
*/
abstract class ByteCharset extends Charset
{
protected char[] lookupTable;
/**
* Char to signify the character in the table is undefined
*/
protected static final char NONE = (char)0xFFFD;
ByteCharset (String canonicalName, String[] aliases)
{
super (canonicalName, aliases);
}
/**
* Most western charsets include ASCII, but this should
* be overloaded for others.
*/
public boolean contains (Charset cs)
{
return cs instanceof US_ASCII || (cs.getClass() == getClass());
}
char[] getLookupTable()
{
return lookupTable;
}
public CharsetDecoder newDecoder ()
{
return new Decoder (this);
}
public CharsetEncoder newEncoder ()
{
return new Encoder (this);
}
private static final class Decoder extends CharsetDecoder
{
private char[] lookup;
// Package-private to avoid a trampoline constructor.
Decoder (ByteCharset cs)
{
super (cs, 1.0f, 1.0f);
lookup = cs.getLookupTable();
}
protected CoderResult decodeLoop (ByteBuffer in, CharBuffer out)
{
// TODO: Optimize this in the case in.hasArray() / out.hasArray()
while (in.hasRemaining ())
{
byte b = in.get ();
char c;
if (!out.hasRemaining ())
{
in.position (in.position () - 1);
return CoderResult.OVERFLOW;
}
if((c = lookup[(int) (b & 0xFF)]) == NONE);
// return CoderResult.unmappableForLength (1);
out.put (c);
}
return CoderResult.UNDERFLOW;
}
}
private static final class Encoder extends CharsetEncoder
{
private byte[] lookup;
// Package-private to avoid a trampoline constructor.
Encoder (ByteCharset cs)
{
super (cs, 1.0f, 1.0f);
char[] lookup_table = cs.getLookupTable();
// Create the inverse look-up table.
// determine required size of encoding_table:
int max = 0;
for (int i = 0; i < lookup_table.length; i++)
{
int c = (int)lookup_table[i];
max = (c > max && c < NONE) ? c : max;
}
lookup = new byte[max+1];
for (int i = 0; i < lookup_table.length; i++)
{
int c = (int)lookup_table[i];
if (c != 0 && c < NONE)
{
lookup[c] = (byte)i;
}
}
}
public boolean canEncode(char c)
{
byte b = (c < lookup.length) ? lookup[c] : 0;
return b != 0 || c == 0;
}
public boolean canEncode(CharSequence cs)
{
for (int i = 0; i < cs.length(); ++i)
{
if (! canEncode(cs.charAt(i)))
return false;
}
return true;
}
protected CoderResult encodeLoop (CharBuffer in, ByteBuffer out)
{
// TODO: Optimize this in the case in.hasArray() / out.hasArray()
while (in.hasRemaining ())
{
int c = (int)in.get ();
if (!out.hasRemaining ())
{
in.position (in.position () - 1);
return CoderResult.OVERFLOW;
}
// lookup byte encoding
byte b = (c < lookup.length) ? lookup[c] : (byte)0;
if ((int)b != 0 || (int)c == 0)
{
out.put (b);
} else {
in.position (in.position () - 1);
return CoderResult.unmappableForLength (1);
}
}
return CoderResult.UNDERFLOW;
}
}
}
|
