1 /*
2  * Copyright (C) 2023 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 #pragma once
18 
19 namespace aidl::android::hardware::bluetooth::audio {
20 
21 class A2dpBits {
22   const uint8_t* cdata_;
23   uint8_t* data_;
24 
25  public:
A2dpBits(const std::vector<uint8_t> & vector)26   A2dpBits(const std::vector<uint8_t>& vector)
27       : cdata_(vector.data()), data_(nullptr) {}
28 
A2dpBits(std::vector<uint8_t> & vector)29   A2dpBits(std::vector<uint8_t>& vector)
30       : cdata_(vector.data()), data_(vector.data()) {}
31 
32   struct Range {
33     const int first, len;
RangeRange34     constexpr Range(int first, int last)
35         : first(first), len(last - first + 1) {}
RangeRange36     constexpr Range(int index) : first(index), len(1) {}
37   };
38 
get(int bit)39   constexpr bool get(int bit) const {
40     return (cdata_[bit >> 3] >> (7 - (bit & 7))) & 1;
41   }
42 
get(const Range & range)43   constexpr unsigned get(const Range& range) const {
44     unsigned v(0);
45     for (int i = 0; i < range.len; i++)
46       v |= get(range.first + i) << ((range.len - 1) - i);
47     return v;
48   }
49 
50   constexpr void set(int bit, int value = 1) {
51     uint8_t m = 1 << (7 - (bit & 7));
52     if (value)
53       data_[bit >> 3] |= m;
54     else
55       data_[bit >> 3] &= ~m;
56   }
57 
set(const Range & range,int value)58   constexpr void set(const Range& range, int value) {
59     for (int i = 0; i < range.len; i++)
60       set(range.first + i, (value >> ((range.len - 1) - i)) & 1);
61   }
62 
find_active_bit(const Range & range)63   constexpr int find_active_bit(const Range& range) const {
64     unsigned v = get(range);
65     int i = 0;
66     for (; i < range.len && ((v >> i) & 1) == 0; i++)
67       ;
68     return i < range.len && (v ^ (1 << i)) == 0
69                ? range.first + (range.len - 1) - i
70                : -1;
71   }
72 };
73 
74 }  // namespace aidl::android::hardware::bluetooth::audio
75