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
17#ifndef A_BIT_READER_H_
18
19#define A_BIT_READER_H_
20
21#include <media/stagefright/foundation/ABase.h>
22
23#include <sys/types.h>
24#include <stdint.h>
25
26namespace android {
27
28class ABitReader {
29public:
30    ABitReader(const uint8_t *data, size_t size);
31    virtual ~ABitReader();
32
33    uint32_t getBits(size_t n);
34    void skipBits(size_t n);
35
36    void putBits(uint32_t x, size_t n);
37
38    size_t numBitsLeft() const;
39
40    const uint8_t *data() const;
41
42protected:
43    const uint8_t *mData;
44    size_t mSize;
45
46    uint32_t mReservoir;  // left-aligned bits
47    size_t mNumBitsLeft;
48
49    virtual void fillReservoir();
50
51    DISALLOW_EVIL_CONSTRUCTORS(ABitReader);
52};
53
54class NALBitReader : public ABitReader {
55public:
56    NALBitReader(const uint8_t *data, size_t size);
57
58    bool atLeastNumBitsLeft(size_t n) const;
59
60private:
61    int32_t mNumZeros;
62
63    virtual void fillReservoir();
64
65    DISALLOW_EVIL_CONSTRUCTORS(NALBitReader);
66};
67
68}  // namespace android
69
70#endif  // A_BIT_READER_H_
71