1/*
2 * Copyright (C) 2010 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17package libcore.io;
18
19import java.nio.ByteOrder;
20import libcore.io.Memory;
21
22/**
23 * Iterates over big- or little-endian bytes in a Java byte[].
24 *
25 * @hide don't make this public without adding bounds checking.
26 */
27public final class HeapBufferIterator extends BufferIterator {
28    private final byte[] buffer;
29    private final int offset;
30    private final int byteCount;
31    private final ByteOrder order;
32
33    private int position;
34
35    HeapBufferIterator(byte[] buffer, int offset, int byteCount, ByteOrder order) {
36        this.buffer = buffer;
37        this.offset = offset;
38        this.byteCount = byteCount;
39        this.order = order;
40    }
41
42    public void seek(int offset) {
43        position = offset;
44    }
45
46    public void skip(int byteCount) {
47        position += byteCount;
48    }
49
50    public void readByteArray(byte[] dst, int dstOffset, int byteCount) {
51        System.arraycopy(buffer, offset + position, dst, dstOffset, byteCount);
52        position += byteCount;
53    }
54
55    public byte readByte() {
56        byte result = buffer[offset + position];
57        ++position;
58        return result;
59    }
60
61    public int readInt() {
62        int result = Memory.peekInt(buffer, offset + position, order);
63        position += SizeOf.INT;
64        return result;
65    }
66
67    public void readIntArray(int[] dst, int dstOffset, int intCount) {
68        final int byteCount = intCount * SizeOf.INT;
69        Memory.unsafeBulkGet(dst, dstOffset, byteCount, buffer, offset + position, SizeOf.INT, order.needsSwap);
70        position += byteCount;
71    }
72
73    public short readShort() {
74        short result = Memory.peekShort(buffer, offset + position, order);
75        position += SizeOf.SHORT;
76        return result;
77    }
78
79    /**
80     * Returns a new iterator over {@code buffer}, starting at {@code offset} and continuing for
81     * {@code byteCount} bytes. Items larger than a byte are interpreted using the given byte order.
82     */
83    public static BufferIterator iterator(byte[] buffer, int offset, int byteCount, ByteOrder order) {
84        return new HeapBufferIterator(buffer, offset, byteCount, order);
85    }
86}
87