| /* 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; |
| } |
| } |
| } |