1/*
2 * Copyright (c) 2000, 2013, 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 java.nio;
27
28import libcore.io.Memory;
29
30class ByteBufferAsCharBuffer extends CharBuffer {      // package-private
31
32    protected final ByteBuffer bb;
33    protected final int offset;
34    private final ByteOrder order;
35
36    ByteBufferAsCharBuffer(ByteBuffer bb,
37                           int mark, int pos, int lim, int cap,
38                           int off, ByteOrder order) {
39        super(mark, pos, lim, cap);
40        this.bb = bb.duplicate();
41        this.isReadOnly = bb.isReadOnly;
42        // There are only two possibilities for the type of ByteBuffer "bb", viz, DirectByteBuffer and
43        // HeapByteBuffer. We only have to initialize the field when bb is an instance of
44        // DirectByteBuffer.
45        // The address field is used by NIOAccess#getBasePointer and GetDirectBufferAddress method
46        // in art which return the address of the first usable byte of the underlying memory, i.e,
47        // the position of parent buffer. Therefore, value of "off" will be equal to parent buffer's
48        // position when the method is called from either HeapByteBuffer or DirectByteBuffer.
49        if (bb instanceof DirectByteBuffer) {
50            this.address = bb.address + off;
51        }
52        this.bb.order(order);
53        this.order = order;
54        offset = off;
55    }
56
57    public CharBuffer slice() {
58        int pos = this.position();
59        int lim = this.limit();
60        assert (pos <= lim);
61        int rem = (pos <= lim ? lim - pos : 0);
62        int off = (pos << 1) + offset;
63        assert (off >= 0);
64        return new ByteBufferAsCharBuffer(bb, -1, 0, rem, rem, off, order);
65    }
66
67    public CharBuffer duplicate() {
68        return new ByteBufferAsCharBuffer(bb,
69                markValue(),
70                position(),
71                limit(),
72                capacity(),
73                offset,
74                order);
75    }
76
77    public CharBuffer asReadOnlyBuffer() {
78        return new ByteBufferAsCharBuffer(bb.asReadOnlyBuffer(),
79                markValue(),
80                position(),
81                limit(),
82                capacity(),
83                offset,
84                order);
85    }
86
87    protected int ix(int i) {
88        return (i << 1) + offset;
89    }
90
91    public char get() {
92        return get(nextGetIndex());
93    }
94
95    public char get(int i) {
96        return bb.getCharUnchecked(ix(checkIndex(i)));
97    }
98
99    public CharBuffer get(char[] dst, int offset, int length) {
100        checkBounds(offset, length, dst.length);
101        if (length > remaining())
102            throw new BufferUnderflowException();
103        bb.getUnchecked(ix(position), dst, offset, length);
104        position += length;
105        return this;
106    }
107
108    char getUnchecked(int i) {
109        return bb.getCharUnchecked(ix(i));
110    }
111
112    public CharBuffer put(char x) {
113        put(nextPutIndex(), x);
114        return this;
115    }
116
117    public CharBuffer put(int i, char x) {
118        if (isReadOnly) {
119            throw new ReadOnlyBufferException();
120        }
121        bb.putCharUnchecked(ix(checkIndex(i)), x);
122        return this;
123    }
124
125    public CharBuffer put(char[] src, int offset, int length) {
126        checkBounds(offset, length, src.length);
127        if (length > remaining())
128            throw new BufferOverflowException();
129        bb.putUnchecked(ix(position), src, offset, length);
130        position += length;
131        return this;
132    }
133
134    public CharBuffer compact() {
135        if (isReadOnly) {
136            throw new ReadOnlyBufferException();
137        }
138        int pos = position();
139        int lim = limit();
140        assert (pos <= lim);
141        int rem = (pos <= lim ? lim - pos : 0);
142        if (!(bb instanceof DirectByteBuffer)) {
143            System.arraycopy(bb.array(), ix(pos), bb.array(), ix(0), rem << 1);
144        } else {
145            Memory.memmove(this, ix(0), this, ix(pos), rem << 1);
146        }
147        position(rem);
148        limit(capacity());
149        discardMark();
150        return this;
151    }
152
153    public boolean isDirect() {
154        return bb.isDirect();
155    }
156
157    public boolean isReadOnly() {
158        return isReadOnly;
159    }
160
161    public String toString(int start, int end) {
162        if ((end > limit()) || (start > end))
163            throw new IndexOutOfBoundsException();
164        try {
165            int len = end - start;
166            char[] ca = new char[len];
167            CharBuffer cb = CharBuffer.wrap(ca);
168            CharBuffer db = this.duplicate();
169            db.position(start);
170            db.limit(end);
171            cb.put(db);
172            return new String(ca);
173        } catch (StringIndexOutOfBoundsException x) {
174            throw new IndexOutOfBoundsException();
175        }
176    }
177
178    // --- Methods to support CharSequence ---
179
180    public CharBuffer subSequence(int start, int end) {
181        int pos = position();
182        int lim = limit();
183        assert (pos <= lim);
184        pos = (pos <= lim ? pos : lim);
185        int len = lim - pos;
186
187        if ((start < 0) || (end > len) || (start > end))
188            throw new IndexOutOfBoundsException();
189        return new ByteBufferAsCharBuffer(bb,
190                -1,
191                pos + start,
192                pos + end,
193                capacity(),
194                offset,
195                order);
196    }
197
198    public ByteOrder order() {
199        return order;
200    }
201}
202