| /* |
| * Copyright 2001-2005 Sun Microsystems, Inc. All Rights Reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. Sun designates this |
| * particular file as subject to the "Classpath" exception as provided |
| * by Sun in the LICENSE file that accompanied this code. |
| * |
| * This code 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 |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| * CA 95054 USA or visit www.sun.com if you need additional information or |
| * have any questions. |
| */ |
| |
| /** |
| * This FilterReader class processes a sequence of characters from |
| * a source stream containing a mixture of 7-bit ASCII data and |
| * 'back-tick U' escaped sequences representing characters which have |
| * the possibility of being encoded in a user specified encoding |
| * The filter relies on knowing the target encoding and makes a |
| * determination as to whether a given supplied character in its |
| * source character stream is encodeable in the target encoding. |
| * If not, it is remains in its back-tick U escaped form. |
| */ |
| |
| package sun.tools.native2ascii; |
| import java.io.*; |
| |
| |
| class A2NFilter extends FilterReader { |
| |
| // maintain a trailing buffer to hold any incompleted |
| // unicode escaped sequences |
| private char[] trailChars = null; |
| |
| public A2NFilter(Reader in) { |
| super(in); |
| } |
| |
| public int read(char[] buf, int off, int len) throws IOException { |
| int numChars = 0; // how many characters have been read |
| int retChars = 0; // how many characters we'll return |
| |
| char[] cBuf = new char[len]; |
| int cOffset = 0; // offset at which we'll start reading |
| boolean eof = false; |
| |
| // copy trailing chars from previous invocation to input buffer |
| if (trailChars != null) { |
| for (int i = 0; i < trailChars.length; i++) |
| cBuf[i] = trailChars[i]; |
| numChars = trailChars.length; |
| trailChars = null; |
| } |
| |
| int n = in.read(cBuf, numChars, len - numChars); |
| if (n < 0) { |
| eof = true; |
| if (numChars == 0) |
| return -1; // EOF; |
| } else { |
| numChars += n; |
| } |
| |
| for (int i = 0; i < numChars;) { |
| char c = cBuf[i++]; |
| |
| if (c != '\\' || (eof && numChars <= 5)) { |
| // Not a backslash, so copy and continue |
| // Always pass non backslash chars straight thru |
| // for regular encoding. If backslash occurs in |
| // input stream at the final 5 chars then don't |
| // attempt to read-ahead and de-escape since these |
| // are literal occurrences of U+005C which need to |
| // be encoded verbatim in the target encoding. |
| buf[retChars++] = c; |
| continue; |
| } |
| |
| int remaining = numChars - i; |
| if (remaining < 5) { |
| // Might be the first character of a unicode escape, but we |
| // don't have enough characters to tell, so save it and finish |
| trailChars = new char[1 + remaining]; |
| trailChars[0] = c; |
| for (int j = 0; j < remaining; j++) |
| trailChars[1 + j] = cBuf[i + j]; |
| break; |
| } |
| // At this point we have at least five characters remaining |
| |
| c = cBuf[i++]; |
| if (c != 'u') { |
| // Not a unicode escape, so copy and continue |
| buf[retChars++] = '\\'; |
| buf[retChars++] = c; |
| continue; |
| } |
| |
| // The next four characters are the hex part of a unicode escape |
| char rc = 0; |
| boolean isUE = true; |
| try { |
| rc = (char)Integer.parseInt(new String(cBuf, i, 4), 16); |
| } catch (NumberFormatException x) { |
| isUE = false; |
| } |
| if (isUE && Main.canConvert(rc)) { |
| // We'll be able to convert this |
| buf[retChars++] = rc; |
| i += 4; // Align beyond the current uXXXX sequence |
| } else { |
| // We won't, so just retain the original sequence |
| buf[retChars++] = '\\'; |
| buf[retChars++] = 'u'; |
| continue; |
| } |
| |
| } |
| |
| return retChars; |
| } |
| |
| public int read() throws IOException { |
| char[] buf = new char[1]; |
| |
| if (read(buf, 0, 1) == -1) |
| return -1; |
| else |
| return (int)buf[0]; |
| } |
| |
| } |