| /* |
| * Copyright (c) 2000, 2006, Oracle and/or its affiliates. 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. Oracle designates this |
| * particular file as subject to the "Classpath" exception as provided |
| * by Oracle 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| |
| package sun.nio.cs; |
| |
| import java.nio.ByteBuffer; |
| import java.nio.CharBuffer; |
| import java.nio.charset.Charset; |
| import java.nio.charset.CharsetDecoder; |
| import java.nio.charset.CoderResult; |
| import java.nio.charset.CharacterCodingException; |
| import java.nio.charset.MalformedInputException; |
| |
| |
| abstract class UnicodeDecoder extends CharsetDecoder { |
| |
| protected static final char BYTE_ORDER_MARK = (char) 0xfeff; |
| protected static final char REVERSED_MARK = (char) 0xfffe; |
| |
| protected static final int NONE = 0; |
| protected static final int BIG = 1; |
| protected static final int LITTLE = 2; |
| |
| private final int expectedByteOrder; |
| private int currentByteOrder; |
| private int defaultByteOrder = BIG; |
| |
| public UnicodeDecoder(Charset cs, int bo) { |
| super(cs, 0.5f, 1.0f); |
| expectedByteOrder = currentByteOrder = bo; |
| } |
| |
| public UnicodeDecoder(Charset cs, int bo, int defaultBO) { |
| this(cs, bo); |
| defaultByteOrder = defaultBO; |
| } |
| |
| private char decode(int b1, int b2) { |
| if (currentByteOrder == BIG) |
| return (char)((b1 << 8) | b2); |
| else |
| return (char)((b2 << 8) | b1); |
| } |
| |
| protected CoderResult decodeLoop(ByteBuffer src, CharBuffer dst) { |
| int mark = src.position(); |
| |
| try { |
| while (src.remaining() > 1) { |
| int b1 = src.get() & 0xff; |
| int b2 = src.get() & 0xff; |
| |
| // Byte Order Mark interpretation |
| if (currentByteOrder == NONE) { |
| char c = (char)((b1 << 8) | b2); |
| if (c == BYTE_ORDER_MARK) { |
| currentByteOrder = BIG; |
| mark += 2; |
| continue; |
| } else if (c == REVERSED_MARK) { |
| currentByteOrder = LITTLE; |
| mark += 2; |
| continue; |
| } else { |
| currentByteOrder = defaultByteOrder; |
| // FALL THROUGH to process b1, b2 normally |
| } |
| } |
| |
| char c = decode(b1, b2); |
| |
| if (c == REVERSED_MARK) { |
| // A reversed BOM cannot occur within middle of stream |
| return CoderResult.malformedForLength(2); |
| } |
| |
| // Surrogates |
| if (Character.isSurrogate(c)) { |
| if (Character.isHighSurrogate(c)) { |
| if (src.remaining() < 2) |
| return CoderResult.UNDERFLOW; |
| char c2 = decode(src.get() & 0xff, src.get() & 0xff); |
| if (!Character.isLowSurrogate(c2)) |
| return CoderResult.malformedForLength(4); |
| if (dst.remaining() < 2) |
| return CoderResult.OVERFLOW; |
| mark += 4; |
| dst.put(c); |
| dst.put(c2); |
| continue; |
| } |
| // Unpaired low surrogate |
| return CoderResult.malformedForLength(2); |
| } |
| |
| if (!dst.hasRemaining()) |
| return CoderResult.OVERFLOW; |
| mark += 2; |
| dst.put(c); |
| |
| } |
| return CoderResult.UNDERFLOW; |
| |
| } finally { |
| src.position(mark); |
| } |
| } |
| |
| protected void implReset() { |
| currentByteOrder = expectedByteOrder; |
| } |
| |
| } |