J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 2000-2006 Sun Microsystems, Inc. All Rights Reserved. |
| 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| 4 | * |
| 5 | * This code is free software; you can redistribute it and/or modify it |
| 6 | * under the terms of the GNU General Public License version 2 only, as |
| 7 | * published by the Free Software Foundation. Sun designates this |
| 8 | * particular file as subject to the "Classpath" exception as provided |
| 9 | * by Sun in the LICENSE file that accompanied this code. |
| 10 | * |
| 11 | * This code is distributed in the hope that it will be useful, but WITHOUT |
| 12 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| 13 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| 14 | * version 2 for more details (a copy is included in the LICENSE file that |
| 15 | * accompanied this code). |
| 16 | * |
| 17 | * You should have received a copy of the GNU General Public License version |
| 18 | * 2 along with this work; if not, write to the Free Software Foundation, |
| 19 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| 20 | * |
| 21 | * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| 22 | * CA 95054 USA or visit www.sun.com if you need additional information or |
| 23 | * have any questions. |
| 24 | */ |
| 25 | |
| 26 | package sun.nio.cs; |
| 27 | |
| 28 | import java.nio.ByteBuffer; |
| 29 | import java.nio.CharBuffer; |
| 30 | import java.nio.charset.Charset; |
| 31 | import java.nio.charset.CharsetDecoder; |
| 32 | import java.nio.charset.CoderResult; |
| 33 | import java.nio.charset.CharacterCodingException; |
| 34 | import java.nio.charset.MalformedInputException; |
| 35 | |
| 36 | |
| 37 | abstract class UnicodeDecoder extends CharsetDecoder { |
| 38 | |
| 39 | protected static final char BYTE_ORDER_MARK = (char) 0xfeff; |
| 40 | protected static final char REVERSED_MARK = (char) 0xfffe; |
| 41 | |
| 42 | protected static final int NONE = 0; |
| 43 | protected static final int BIG = 1; |
| 44 | protected static final int LITTLE = 2; |
| 45 | |
| 46 | private final int expectedByteOrder; |
| 47 | private int currentByteOrder; |
| 48 | private int defaultByteOrder = BIG; |
| 49 | |
| 50 | public UnicodeDecoder(Charset cs, int bo) { |
| 51 | super(cs, 0.5f, 1.0f); |
| 52 | expectedByteOrder = currentByteOrder = bo; |
| 53 | } |
| 54 | |
| 55 | public UnicodeDecoder(Charset cs, int bo, int defaultBO) { |
| 56 | this(cs, bo); |
| 57 | defaultByteOrder = defaultBO; |
| 58 | } |
| 59 | |
| 60 | private char decode(int b1, int b2) { |
| 61 | if (currentByteOrder == BIG) |
| 62 | return (char)((b1 << 8) | b2); |
| 63 | else |
| 64 | return (char)((b2 << 8) | b1); |
| 65 | } |
| 66 | |
| 67 | protected CoderResult decodeLoop(ByteBuffer src, CharBuffer dst) { |
| 68 | int mark = src.position(); |
| 69 | |
| 70 | try { |
| 71 | while (src.remaining() > 1) { |
| 72 | int b1 = src.get() & 0xff; |
| 73 | int b2 = src.get() & 0xff; |
| 74 | |
| 75 | // Byte Order Mark interpretation |
| 76 | if (currentByteOrder == NONE) { |
| 77 | char c = (char)((b1 << 8) | b2); |
| 78 | if (c == BYTE_ORDER_MARK) { |
| 79 | currentByteOrder = BIG; |
| 80 | mark += 2; |
| 81 | continue; |
| 82 | } else if (c == REVERSED_MARK) { |
| 83 | currentByteOrder = LITTLE; |
| 84 | mark += 2; |
| 85 | continue; |
| 86 | } else { |
| 87 | currentByteOrder = defaultByteOrder; |
| 88 | // FALL THROUGH to process b1, b2 normally |
| 89 | } |
| 90 | } |
| 91 | |
| 92 | char c = decode(b1, b2); |
| 93 | |
| 94 | if (c == REVERSED_MARK) { |
| 95 | // A reversed BOM cannot occur within middle of stream |
| 96 | return CoderResult.malformedForLength(2); |
| 97 | } |
| 98 | |
| 99 | // Surrogates |
| 100 | if (Surrogate.is(c)) { |
| 101 | if (Surrogate.isHigh(c)) { |
| 102 | if (src.remaining() < 2) |
| 103 | return CoderResult.UNDERFLOW; |
| 104 | char c2 = decode(src.get() & 0xff, src.get() & 0xff); |
| 105 | if (!Surrogate.isLow(c2)) |
| 106 | return CoderResult.malformedForLength(4); |
| 107 | if (dst.remaining() < 2) |
| 108 | return CoderResult.OVERFLOW; |
| 109 | mark += 4; |
| 110 | dst.put(c); |
| 111 | dst.put(c2); |
| 112 | continue; |
| 113 | } |
| 114 | // Unpaired low surrogate |
| 115 | return CoderResult.malformedForLength(2); |
| 116 | } |
| 117 | |
| 118 | if (!dst.hasRemaining()) |
| 119 | return CoderResult.OVERFLOW; |
| 120 | mark += 2; |
| 121 | dst.put(c); |
| 122 | |
| 123 | } |
| 124 | return CoderResult.UNDERFLOW; |
| 125 | |
| 126 | } finally { |
| 127 | src.position(mark); |
| 128 | } |
| 129 | } |
| 130 | |
| 131 | protected void implReset() { |
| 132 | currentByteOrder = expectedByteOrder; |
| 133 | } |
| 134 | |
| 135 | } |