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 
26 package java.nio;
27 
28 import libcore.io.Memory;
29 
30 class ByteBufferAsCharBuffer extends CharBuffer {      // package-private
31 
32     protected final ByteBuffer bb;
33     protected final int offset;
34     private final ByteOrder order;
35 
ByteBufferAsCharBuffer(ByteBuffer bb, int mark, int pos, int lim, int cap, int off, ByteOrder order)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 
slice()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 
duplicate()67     public CharBuffer duplicate() {
68         return new ByteBufferAsCharBuffer(bb,
69                 markValue(),
70                 position(),
71                 limit(),
72                 capacity(),
73                 offset,
74                 order);
75     }
76 
asReadOnlyBuffer()77     public CharBuffer asReadOnlyBuffer() {
78         return new ByteBufferAsCharBuffer(bb.asReadOnlyBuffer(),
79                 markValue(),
80                 position(),
81                 limit(),
82                 capacity(),
83                 offset,
84                 order);
85     }
86 
ix(int i)87     protected int ix(int i) {
88         return (i << 1) + offset;
89     }
90 
get()91     public char get() {
92         return get(nextGetIndex());
93     }
94 
get(int i)95     public char get(int i) {
96         return bb.getCharUnchecked(ix(checkIndex(i)));
97     }
98 
get(char[] dst, int offset, int length)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 
getUnchecked(int i)108     char getUnchecked(int i) {
109         return bb.getCharUnchecked(ix(i));
110     }
111 
put(char x)112     public CharBuffer put(char x) {
113         put(nextPutIndex(), x);
114         return this;
115     }
116 
put(int i, char x)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 
put(char[] src, int offset, int length)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 
compact()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 
isDirect()153     public boolean isDirect() {
154         return bb.isDirect();
155     }
156 
isReadOnly()157     public boolean isReadOnly() {
158         return isReadOnly;
159     }
160 
toString(int start, int end)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 
subSequence(int start, int end)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 
order()198     public ByteOrder order() {
199         return order;
200     }
201 }
202