1// Copyright (c) 2012 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#ifndef MEDIA_BASE_BIT_READER_H_
6#define MEDIA_BASE_BIT_READER_H_
7
8#include "base/basictypes.h"
9#include "base/compiler_specific.h"
10#include "base/memory/scoped_ptr.h"
11#include "media/base/bit_reader_core.h"
12#include "media/base/media_export.h"
13
14namespace media {
15
16class MEDIA_EXPORT BitReader
17    : NON_EXPORTED_BASE(private BitReaderCore::ByteStreamProvider)  {
18 public:
19  // Initialize the reader to start reading at |data|, |size| being size
20  // of |data| in bytes.
21  BitReader(const uint8* data, int size);
22  virtual ~BitReader();
23
24  template<typename T> bool ReadBits(int num_bits, T* out) {
25    return bit_reader_core_.ReadBits(num_bits, out);
26  }
27
28  bool ReadFlag(bool* flag) {
29    return bit_reader_core_.ReadFlag(flag);
30  }
31
32  bool SkipBits(int num_bits) {
33    return bit_reader_core_.SkipBits(num_bits);
34  }
35
36  int bits_available() const {
37    return initial_size_ * 8 - bits_read();
38  }
39
40  int bits_read() const {
41    return bit_reader_core_.bits_read();
42  }
43
44 private:
45  // BitReaderCore::ByteStreamProvider implementation.
46  virtual int GetBytes(int max_n, const uint8** out) OVERRIDE;
47
48  // Total number of bytes that was initially passed to BitReader.
49  const int initial_size_;
50
51  // Pointer to the next unread byte in the stream.
52  const uint8* data_;
53
54  // Bytes left in the stream.
55  int bytes_left_;
56
57  BitReaderCore bit_reader_core_;
58
59  DISALLOW_COPY_AND_ASSIGN(BitReader);
60};
61
62}  // namespace media
63
64#endif  // MEDIA_BASE_BIT_READER_H_
65