1 /* |
|
2 * Copyright (c) 2001, 2005, 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 * This FilterReader class processes a sequence of characters from |
|
28 * a source stream containing a mixture of 7-bit ASCII data and |
|
29 * 'back-tick U' escaped sequences representing characters which have |
|
30 * the possibility of being encoded in a user specified encoding |
|
31 * The filter relies on knowing the target encoding and makes a |
|
32 * determination as to whether a given supplied character in its |
|
33 * source character stream is encodeable in the target encoding. |
|
34 * If not, it is remains in its back-tick U escaped form. |
|
35 */ |
|
36 |
|
37 package sun.tools.native2ascii; |
|
38 import java.io.*; |
|
39 |
|
40 |
|
41 class A2NFilter extends FilterReader { |
|
42 |
|
43 // maintain a trailing buffer to hold any incompleted |
|
44 // unicode escaped sequences |
|
45 private char[] trailChars = null; |
|
46 |
|
47 public A2NFilter(Reader in) { |
|
48 super(in); |
|
49 } |
|
50 |
|
51 public int read(char[] buf, int off, int len) throws IOException { |
|
52 int numChars = 0; // how many characters have been read |
|
53 int retChars = 0; // how many characters we'll return |
|
54 |
|
55 char[] cBuf = new char[len]; |
|
56 int cOffset = 0; // offset at which we'll start reading |
|
57 boolean eof = false; |
|
58 |
|
59 // copy trailing chars from previous invocation to input buffer |
|
60 if (trailChars != null) { |
|
61 for (int i = 0; i < trailChars.length; i++) |
|
62 cBuf[i] = trailChars[i]; |
|
63 numChars = trailChars.length; |
|
64 trailChars = null; |
|
65 } |
|
66 |
|
67 int n = in.read(cBuf, numChars, len - numChars); |
|
68 if (n < 0) { |
|
69 eof = true; |
|
70 if (numChars == 0) |
|
71 return -1; // EOF; |
|
72 } else { |
|
73 numChars += n; |
|
74 } |
|
75 |
|
76 for (int i = 0; i < numChars;) { |
|
77 char c = cBuf[i++]; |
|
78 |
|
79 if (c != '\\' || (eof && numChars <= 5)) { |
|
80 // Not a backslash, so copy and continue |
|
81 // Always pass non backslash chars straight thru |
|
82 // for regular encoding. If backslash occurs in |
|
83 // input stream at the final 5 chars then don't |
|
84 // attempt to read-ahead and de-escape since these |
|
85 // are literal occurrences of U+005C which need to |
|
86 // be encoded verbatim in the target encoding. |
|
87 buf[retChars++] = c; |
|
88 continue; |
|
89 } |
|
90 |
|
91 int remaining = numChars - i; |
|
92 if (remaining < 5) { |
|
93 // Might be the first character of a unicode escape, but we |
|
94 // don't have enough characters to tell, so save it and finish |
|
95 trailChars = new char[1 + remaining]; |
|
96 trailChars[0] = c; |
|
97 for (int j = 0; j < remaining; j++) |
|
98 trailChars[1 + j] = cBuf[i + j]; |
|
99 break; |
|
100 } |
|
101 // At this point we have at least five characters remaining |
|
102 |
|
103 c = cBuf[i++]; |
|
104 if (c != 'u') { |
|
105 // Not a unicode escape, so copy and continue |
|
106 buf[retChars++] = '\\'; |
|
107 buf[retChars++] = c; |
|
108 continue; |
|
109 } |
|
110 |
|
111 // The next four characters are the hex part of a unicode escape |
|
112 char rc = 0; |
|
113 boolean isUE = true; |
|
114 try { |
|
115 rc = (char)Integer.parseInt(new String(cBuf, i, 4), 16); |
|
116 } catch (NumberFormatException x) { |
|
117 isUE = false; |
|
118 } |
|
119 if (isUE && Main.canConvert(rc)) { |
|
120 // We'll be able to convert this |
|
121 buf[retChars++] = rc; |
|
122 i += 4; // Align beyond the current uXXXX sequence |
|
123 } else { |
|
124 // We won't, so just retain the original sequence |
|
125 buf[retChars++] = '\\'; |
|
126 buf[retChars++] = 'u'; |
|
127 continue; |
|
128 } |
|
129 |
|
130 } |
|
131 |
|
132 return retChars; |
|
133 } |
|
134 |
|
135 public int read() throws IOException { |
|
136 char[] buf = new char[1]; |
|
137 |
|
138 if (read(buf, 0, 1) == -1) |
|
139 return -1; |
|
140 else |
|
141 return (int)buf[0]; |
|
142 } |
|
143 |
|
144 } |
|