1 /*
2  * Copyright 2015, 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 ANDROID_AUDIO_BIT_FIELD_PARSER_H
18 #define ANDROID_AUDIO_BIT_FIELD_PARSER_H
19 
20 #include <stdint.h>
21 
22 namespace android {
23 
24 /**
25  * Extract bit fields from a byte array.
26  */
27 class BitFieldParser {
28 public:
29 
30     explicit BitFieldParser(uint8_t *data);
31     virtual ~BitFieldParser();
32 
33     /**
34      * Read numBits bits from the data array.
35      * Fields may span byte boundaries but may not exceed 32-bits.
36      * Note that the caller must ensure that there is suffcient data.
37      * Assume data is organized as BigEndian format.
38      */
39     uint32_t readBits(uint32_t numBits);
40 
41     /*
42      * When the cursor is zero it points to a position right before
43      * the most significant bit.
44      * When the cursor is seven it points to a position right before
45      * the least significant bit.
46      */
getBitCursor()47     uint32_t getBitCursor() const { return mBitCursor; }
48 
49 private:
50     uint8_t *mData;
51     uint32_t mBitCursor;
52 };
53 
54 
55 }  // namespace android
56 
57 #endif  // ANDROID_AUDIO_BIT_FIELD_PARSER_H
58