1/*
2 * Copyright (c) 2000, 2010, Oracle and/or its affiliates. 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.  Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25
26package sun.nio.cs;
27
28import java.nio.*;
29import java.nio.charset.*;
30
31/**
32 * Base class for different flavors of UTF-16 encoders
33 */
34public abstract class UnicodeEncoder extends CharsetEncoder {
35
36    protected static final char BYTE_ORDER_MARK = '\uFEFF';
37    protected static final char REVERSED_MARK = '\uFFFE';
38
39    protected static final int BIG = 0;
40    protected static final int LITTLE = 1;
41
42    private int byteOrder;      /* Byte order in use */
43    private boolean usesMark;   /* Write an initial BOM */
44    private boolean needsMark;
45
46    protected UnicodeEncoder(Charset cs, int bo, boolean m) {
47        super(cs, 2.0f,
48              // Four bytes max if you need a BOM
49              m ? 4.0f : 2.0f,
50              // Replacement depends upon byte order
51              ((bo == BIG)
52               ? new byte[] { (byte)0xff, (byte)0xfd }
53               : new byte[] { (byte)0xfd, (byte)0xff }));
54        usesMark = needsMark = m;
55        byteOrder = bo;
56    }
57
58    private void put(char c, ByteBuffer dst) {
59        if (byteOrder == BIG) {
60            dst.put((byte)(c >> 8));
61            dst.put((byte)(c & 0xff));
62        } else {
63            dst.put((byte)(c & 0xff));
64            dst.put((byte)(c >> 8));
65        }
66    }
67
68    private final Surrogate.Parser sgp = new Surrogate.Parser();
69
70    protected CoderResult encodeLoop(CharBuffer src, ByteBuffer dst) {
71        int mark = src.position();
72
73        if (needsMark && src.hasRemaining()) {
74            if (dst.remaining() < 2)
75                return CoderResult.OVERFLOW;
76            put(BYTE_ORDER_MARK, dst);
77            needsMark = false;
78        }
79        try {
80            while (src.hasRemaining()) {
81                char c = src.get();
82                if (!Character.isSurrogate(c)) {
83                    if (dst.remaining() < 2)
84                        return CoderResult.OVERFLOW;
85                    mark++;
86                    put(c, dst);
87                    continue;
88                }
89                int d = sgp.parse(c, src);
90                if (d < 0)
91                    return sgp.error();
92                if (dst.remaining() < 4)
93                    return CoderResult.OVERFLOW;
94                mark += 2;
95                put(Character.highSurrogate(d), dst);
96                put(Character.lowSurrogate(d), dst);
97            }
98            return CoderResult.UNDERFLOW;
99        } finally {
100            src.position(mark);
101        }
102    }
103
104    protected void implReset() {
105        needsMark = usesMark;
106    }
107
108    public boolean canEncode(char c) {
109        return ! Character.isSurrogate(c);
110    }
111}
112