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Diffstat (limited to 'libjava/classpath/gnu/java/nio/charset/ByteCharset.java')
| -rw-r--r-- | libjava/classpath/gnu/java/nio/charset/ByteCharset.java | 187 |
1 files changed, 187 insertions, 0 deletions
diff --git a/libjava/classpath/gnu/java/nio/charset/ByteCharset.java b/libjava/classpath/gnu/java/nio/charset/ByteCharset.java new file mode 100644 index 00000000000..2cc91b850f6 --- /dev/null +++ b/libjava/classpath/gnu/java/nio/charset/ByteCharset.java @@ -0,0 +1,187 @@ +/* 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; + } + } + } + + 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; + } + } +} |
