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 <cassert> 20 #include <cstdint> 21 #include <forward_list> 22 #include <iterator> 23 #include <memory> 24 #include <vector> 25 26 #include "packet/bit_inserter.h" 27 #include "packet/custom_field_fixed_size_interface.h" 28 29 namespace bluetooth { 30 namespace packet { 31 32 // Abstract base class that is subclassed to provide insert() functions. 33 // The template parameter little_endian controls the generation of insert(). 34 template <bool little_endian> 35 class EndianInserter { 36 public: 37 EndianInserter() = default; 38 virtual ~EndianInserter() = default; 39 40 protected: 41 // Write sizeof(T) bytes using the iterator 42 template <typename T, typename std::enable_if<std::is_trivial<T>::value, int>::type = 0> insert(T value,BitInserter & it)43 void insert(T value, BitInserter& it) const { 44 uint8_t* raw_bytes = (uint8_t*)&value; 45 for (size_t i = 0; i < sizeof(T); i++) { 46 if (little_endian == true) { 47 it.insert_byte(raw_bytes[i]); 48 } else { 49 it.insert_byte(raw_bytes[sizeof(T) - i - 1]); 50 } 51 } 52 } 53 54 // Write sizeof(FixedWidthCustomType) bytes using the iterator 55 template < 56 typename T, 57 typename std::enable_if<std::is_base_of<CustomFieldFixedSizeInterface<T>, T>::value, int>::type = 0> insert(const T & value,BitInserter & it)58 void insert(const T& value, BitInserter& it) const { 59 auto* raw_bytes = value.data(); 60 for (size_t i = 0; i < CustomFieldFixedSizeInterface<T>::length(); i++) { 61 if (little_endian == true) { 62 it.insert_byte(raw_bytes[i]); 63 } else { 64 it.insert_byte(raw_bytes[CustomFieldFixedSizeInterface<T>::length() - i - 1]); 65 } 66 } 67 } 68 69 // Write num_bits bits using the iterator 70 template <typename T, typename std::enable_if<std::is_trivial<T>::value, int>::type = 0> insert(T value,BitInserter & it,size_t num_bits)71 void insert(T value, BitInserter& it, size_t num_bits) const { 72 assert(num_bits <= (sizeof(T) * 8)); 73 74 for (size_t i = 0; i < num_bits / 8; i++) { 75 if (little_endian == true) { 76 it.insert_byte(static_cast<uint8_t>(static_cast<uint64_t>(value) >> (i * 8))); 77 } else { 78 it.insert_byte(static_cast<uint8_t>(static_cast<uint64_t>(value) >> (((num_bits / 8) - i - 1) * 8))); 79 } 80 } 81 if (num_bits % 8) { 82 it.insert_bits(static_cast<uint8_t>(static_cast<uint64_t>(value) >> ((num_bits / 8) * 8)), num_bits % 8); 83 } 84 } 85 86 // Specialized insert that allows inserting enums without casting 87 template <typename Enum, typename std::enable_if<std::is_enum_v<Enum>, int>::type = 0> insert(Enum value,BitInserter & it)88 inline void insert(Enum value, BitInserter& it) const { 89 using enum_type = typename std::underlying_type_t<Enum>; 90 static_assert(std::is_unsigned_v<enum_type>, "Enum type is signed. Did you forget to specify the enum size?"); 91 insert<enum_type>(static_cast<enum_type>(value), it); 92 } 93 94 // Write a vector of T using the iterator 95 template <typename T, typename std::enable_if<std::is_trivial<T>::value, int>::type = 0> insert_vector(const std::vector<T> & vec,BitInserter & it)96 void insert_vector(const std::vector<T>& vec, BitInserter& it) const { 97 static_assert( 98 std::is_trivial<T>::value, 99 "EndianInserter::insert requires a vector with elements of a fixed-size."); 100 for (const auto& element : vec) { 101 insert(element, it); 102 } 103 } 104 }; 105 106 } // namespace packet 107 } // namespace bluetooth 108