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25 
26 package java.nio;
27 
28 import libcore.io.Memory;
29 
30 class ByteBufferAsShortBuffer extends ShortBuffer {       // package-private
31 
32     protected final ByteBuffer bb;
33     protected final int offset;
34     private final ByteOrder order;
35 
ByteBufferAsShortBuffer(ByteBuffer bb, int mark, int pos, int lim, int cap, int off, ByteOrder order)36     ByteBufferAsShortBuffer(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 use 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 ShortBuffer 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 ByteBufferAsShortBuffer(bb, -1, 0, rem, rem, off, order);
65     }
66 
duplicate()67     public ShortBuffer duplicate() {
68         return new ByteBufferAsShortBuffer(bb,
69                 this.markValue(),
70                 this.position(),
71                 this.limit(),
72                 this.capacity(),
73                 offset, order);
74     }
75 
asReadOnlyBuffer()76     public ShortBuffer asReadOnlyBuffer() {
77         return new ByteBufferAsShortBuffer(bb.asReadOnlyBuffer(),
78                 this.markValue(),
79                 this.position(),
80                 this.limit(),
81                 this.capacity(),
82                 offset, order);
83     }
84 
ix(int i)85     protected int ix(int i) {
86         return (i << 1) + offset;
87     }
88 
get()89     public short get() {
90         return get(nextGetIndex());
91     }
92 
get(int i)93     public short get(int i) {
94         return bb.getShortUnchecked(ix(checkIndex(i)));
95 
96     }
97 
get(short[] dst, int offset, int length)98     public ShortBuffer get(short[] dst, int offset, int length) {
99         checkBounds(offset, length, dst.length);
100         if (length > remaining())
101             throw new BufferUnderflowException();
102         bb.getUnchecked(ix(position), dst, offset, length);
103         position += length;
104         return this;
105     }
106 
put(short x)107     public ShortBuffer put(short x) {
108         put(nextPutIndex(), x);
109         return this;
110     }
111 
put(int i, short x)112     public ShortBuffer put(int i, short x) {
113         if (isReadOnly) {
114             throw new ReadOnlyBufferException();
115         }
116         bb.putShortUnchecked(ix(checkIndex(i)), x);
117         return this;
118     }
119 
put(short[] src, int offset, int length)120     public ShortBuffer put(short[] src, int offset, int length) {
121         checkBounds(offset, length, src.length);
122         if (length > remaining())
123             throw new BufferOverflowException();
124         bb.putUnchecked(ix(position), src, offset, length);
125         position += length;
126         return this;
127     }
128 
compact()129     public ShortBuffer compact() {
130         if (isReadOnly) {
131             throw new ReadOnlyBufferException();
132         }
133         int pos = position();
134         int lim = limit();
135         assert (pos <= lim);
136         int rem = (pos <= lim ? lim - pos : 0);
137         if (!(bb instanceof DirectByteBuffer)) {
138             System.arraycopy(bb.array(), ix(pos), bb.array(), ix(0), rem << 1);
139         } else {
140             Memory.memmove(this, ix(0), this, ix(pos), rem << 1);
141         }
142         position(rem);
143         limit(capacity());
144         discardMark();
145         return this;
146     }
147 
isDirect()148     public boolean isDirect() {
149         return bb.isDirect();
150     }
151 
isReadOnly()152     public boolean isReadOnly() {
153         return isReadOnly;
154     }
155 
order()156     public ByteOrder order() {
157         return order;
158     }
159 }
160