1 /* 2 * Copyright 2019 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 #include <cstdint> 20 #include <iterator> 21 #include <memory> 22 #include <vector> 23 24 #include "os/log.h" 25 26 namespace bluetooth { 27 namespace packet { 28 29 class BitInserter : public std::back_insert_iterator<std::vector<uint8_t>> { 30 public: BitInserter(std::vector<uint8_t> & vector)31 BitInserter(std::vector<uint8_t>& vector) : std::back_insert_iterator<std::vector<uint8_t>>(vector) {} ~BitInserter()32 virtual ~BitInserter() { 33 ASSERT(num_saved_bits_ == 0); 34 } 35 insert_bits(uint8_t byte,size_t num_bits)36 void insert_bits(uint8_t byte, size_t num_bits) { 37 size_t total_bits = num_bits + num_saved_bits_; 38 uint16_t new_value = saved_bits_ | (static_cast<uint16_t>(byte) << num_saved_bits_); 39 if (total_bits >= 8) { 40 uint8_t new_byte = static_cast<uint8_t>(new_value); 41 std::back_insert_iterator<std::vector<uint8_t>>::operator=(new_byte); 42 total_bits -= 8; 43 new_value = new_value >> 8; 44 } 45 num_saved_bits_ = total_bits; 46 uint8_t mask = 0xff >> (8 - num_saved_bits_); 47 saved_bits_ = static_cast<uint8_t>(new_value) & mask; 48 } 49 insert_byte(uint8_t byte)50 void insert_byte(uint8_t byte) { 51 insert_bits(byte, 8); 52 } 53 IsByteAligned()54 bool IsByteAligned() { 55 return num_saved_bits_ == 0; 56 } 57 58 private: 59 size_t num_saved_bits_{0}; 60 uint8_t saved_bits_{0}; 61 }; 62 63 } // namespace packet 64 } // namespace bluetooth 65