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25 
26 package java.nio;
27 
28 import libcore.io.Memory;
29 
30 class ByteBufferAsDoubleBuffer
31         extends DoubleBuffer {            // package-private
32 
33     protected final ByteBuffer bb;
34     protected final int offset;
35     private final ByteOrder order;
36 
ByteBufferAsDoubleBuffer(ByteBuffer bb, int mark, int pos, int lim, int cap, int off, ByteOrder order)37     ByteBufferAsDoubleBuffer(ByteBuffer bb,
38                              int mark, int pos, int lim, int cap,
39                              int off, ByteOrder order) {
40         super(mark, pos, lim, cap);
41         this.bb = bb.duplicate();
42         this.isReadOnly = bb.isReadOnly;
43         // There are only two possibilities for the type of ByteBuffer "bb", viz, DirectByteBuffer and
44         // HeapByteBuffer. We only have to initialize the field when bb is an instance of
45         // DirectByteBuffer.
46         // The address field is used by NIOAccess#getBasePointer and GetDirectBufferAddress method
47         // in art which return the address of the first usable byte of the underlying memory, i.e,
48         // the position of parent buffer. Therefore, value of "off" will be equal to parent buffer's
49         // position when the method is called from either HeapByteBuffer or DirectByteBuffer.
50         if (bb instanceof DirectByteBuffer) {
51             this.address = bb.address + off;
52         }
53         this.bb.order(order);
54         this.order = order;
55         offset = off;
56     }
57 
slice()58     public DoubleBuffer slice() {
59         int pos = this.position();
60         int lim = this.limit();
61         assert (pos <= lim);
62         int rem = (pos <= lim ? lim - pos : 0);
63         int off = (pos << 3) + offset;
64         assert (off >= 0);
65         return new ByteBufferAsDoubleBuffer(bb, -1, 0, rem, rem, off, order);
66     }
67 
duplicate()68     public DoubleBuffer duplicate() {
69         return new ByteBufferAsDoubleBuffer(bb,
70                 markValue(),
71                 position(),
72                 limit(),
73                 capacity(),
74                 offset,
75                 order);
76     }
77 
asReadOnlyBuffer()78     public DoubleBuffer asReadOnlyBuffer() {
79         return new ByteBufferAsDoubleBuffer(bb.asReadOnlyBuffer(),
80                 markValue(),
81                 position(),
82                 limit(),
83                 capacity(),
84                 offset,
85                 order);
86     }
87 
ix(int i)88     protected int ix(int i) {
89         return (i << 3) + offset;
90     }
91 
get()92     public double get() {
93         return get(nextGetIndex());
94     }
95 
get(int i)96     public double get(int i) {
97         return bb.getDoubleUnchecked(ix(checkIndex(i)));
98     }
99 
get(double[] dst, int offset, int length)100     public DoubleBuffer get(double[] dst, int offset, int length) {
101         checkBounds(offset, length, dst.length);
102         if (length > remaining())
103             throw new BufferUnderflowException();
104         bb.getUnchecked(ix(position), dst, offset, length);
105         position += length;
106         return this;
107     }
108 
put(double x)109     public DoubleBuffer put(double x) {
110         put(nextPutIndex(), x);
111         return this;
112     }
113 
put(int i, double x)114     public DoubleBuffer put(int i, double x) {
115         if (isReadOnly) {
116             throw new ReadOnlyBufferException();
117         }
118         bb.putDoubleUnchecked(ix(checkIndex(i)), x);
119         return this;
120     }
121 
put(double[] src, int offset, int length)122     public DoubleBuffer put(double[] src, int offset, int length) {
123         checkBounds(offset, length, src.length);
124         if (length > remaining())
125             throw new BufferOverflowException();
126         bb.putUnchecked(ix(position), src, offset, length);
127         position += length;
128         return this;
129     }
130 
compact()131     public DoubleBuffer compact() {
132         if (isReadOnly) {
133             throw new ReadOnlyBufferException();
134         }
135         int pos = position();
136         int lim = limit();
137         assert (pos <= lim);
138         int rem = (pos <= lim ? lim - pos : 0);
139         if (!(bb instanceof DirectByteBuffer)) {
140             System.arraycopy(bb.array(), ix(pos), bb.array(), ix(0), rem << 3);
141         } else {
142             Memory.memmove(this, ix(0), this, ix(pos), rem << 3);
143         }
144         position(rem);
145         limit(capacity());
146         discardMark();
147         return this;
148     }
149 
isDirect()150     public boolean isDirect() {
151         return bb.isDirect();
152     }
153 
isReadOnly()154     public boolean isReadOnly() {
155         return isReadOnly;
156     }
157 
order()158     public ByteOrder order() {
159         return order;
160     }
161 }
162