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 
26 namespace stagefright {
27 
28 struct ABitReader {
29     ABitReader(const uint8_t *data, size_t size);
30 
31     uint32_t getBits(size_t n);
32     void skipBits(size_t n);
33 
34     void putBits(uint32_t x, size_t n);
35 
36     size_t numBitsLeft() const;
37 
38     const uint8_t *data() const;
39 
40 private:
41     const uint8_t *mData;
42     size_t mSize;
43 
44     uint32_t mReservoir;  // left-aligned bits
45     size_t mNumBitsLeft;
46 
47     void fillReservoir();
48 
49     DISALLOW_EVIL_CONSTRUCTORS(ABitReader);
50 };
51 
52 }  // namespace stagefright
53 
54 #endif  // A_BIT_READER_H_
55