| /* 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.CoderResult; |
| |
| /** |
| * Helper class to deal with decoding loops that read a byte at a time |
| * |
| * @author Ian Rogers |
| */ |
| public abstract class ByteDecodeLoopHelper |
| { |
| /** |
| * @return can the given byte be encoded |
| */ |
| protected abstract boolean isMappable(byte b); |
| |
| /** |
| * Map the given byte to a char, the given byte is guaranteed to be mappable |
| */ |
| protected abstract char mapToChar(byte b); |
| |
| /** |
| * Encodes one or more characters into one or more bytes, mapping each |
| * character to only one byte |
| * |
| * @param in character buffer to read from |
| * @param out byte buffer to write to |
| * @return the result state of the encoder |
| */ |
| CoderResult decodeLoop(ByteBuffer in, CharBuffer out) |
| { |
| if (in.hasArray() && out.hasArray()) |
| { |
| return arrayDecodeLoop(in, out); |
| } else |
| { |
| return normalDecodeLoop(in, out); |
| } |
| } |
| |
| /** |
| * Encode loop using get and put operations |
| */ |
| private CoderResult normalDecodeLoop(ByteBuffer in, CharBuffer out) |
| { |
| int outRemaining = out.remaining(); |
| int inRemaining = in.remaining(); |
| while (inRemaining > 0 && outRemaining > 0) |
| { |
| byte b = in.get(); |
| inRemaining--; |
| |
| if (!isMappable(b)) |
| { |
| in.position(in.position() - 1); |
| return CoderResult.unmappableForLength(1); |
| } |
| char c = mapToChar(b); |
| out.put(c); |
| outRemaining--; |
| } |
| if (inRemaining > 0) |
| { |
| return CoderResult.OVERFLOW; |
| } else |
| { |
| return CoderResult.UNDERFLOW; |
| } |
| } |
| |
| /** |
| * Encode loop using array read and write operations |
| */ |
| private CoderResult arrayDecodeLoop(ByteBuffer in, CharBuffer out) |
| { |
| byte[] inArray = in.array(); |
| char[] outArray = out.array(); |
| int inPos = in.arrayOffset() + in.position(); |
| int outPos = out.arrayOffset() + out.position(); |
| int inRemaining = in.remaining(); |
| int outRemaining = out.remaining(); |
| CoderResult result; |
| |
| bailOut: |
| if (inRemaining <= outRemaining) |
| { |
| for (int i = 0; i < inRemaining; i++) |
| { |
| byte b = inArray[inPos]; |
| inPos++; |
| if (!isMappable(b)) |
| { |
| inPos--; |
| result = CoderResult.unmappableForLength(1); |
| break bailOut; |
| } |
| char c = mapToChar(b); |
| outArray[outPos] = c; |
| outPos++; |
| } |
| result = CoderResult.UNDERFLOW; |
| } |
| else |
| { |
| for (int i = 0; i < outRemaining; i++) |
| { |
| byte b = inArray[inPos]; |
| inPos++; |
| if (!isMappable(b)) |
| { |
| inPos--; |
| result = CoderResult.unmappableForLength(1); |
| break bailOut; |
| } |
| char c = mapToChar(b); |
| outArray[outPos] = c; |
| outPos++; |
| } |
| result = CoderResult.OVERFLOW; |
| } |
| in.position(inPos - in.arrayOffset()); |
| out.position(outPos - out.arrayOffset()); |
| return result; |
| } |
| } |