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/*
* Copyright 2019 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#pragma once
#include <cstdint>
#include <forward_list>
#include <iterator>
#include <memory>
#include <vector>
#include "os/log.h"
#include "packet/bit_inserter.h"
#include "packet/custom_field_fixed_size_interface.h"
namespace bluetooth {
namespace packet {
// Abstract base class that is subclassed to provide insert() functions.
// The template parameter little_endian controls the generation of insert().
template <bool little_endian>
class EndianInserter {
public:
EndianInserter() = default;
virtual ~EndianInserter() = default;
protected:
// Write sizeof(FixedWidthPODType) bytes using the iterator
template <typename FixedWidthPODType, typename std::enable_if<std::is_pod<FixedWidthPODType>::value, int>::type = 0>
void insert(FixedWidthPODType value, BitInserter& it) const {
uint8_t* raw_bytes = (uint8_t*)&value;
for (size_t i = 0; i < sizeof(FixedWidthPODType); i++) {
if (little_endian == true) {
it.insert_byte(raw_bytes[i]);
} else {
it.insert_byte(raw_bytes[sizeof(FixedWidthPODType) - i - 1]);
}
}
}
// Write sizeof(FixedWidthCustomType) bytes using the iterator
template <
typename T,
typename std::enable_if<std::is_base_of<CustomFieldFixedSizeInterface<T>, T>::value, int>::type = 0>
void insert(const T& value, BitInserter& it) const {
auto* raw_bytes = value.data();
for (size_t i = 0; i < CustomFieldFixedSizeInterface<T>::length(); i++) {
if (little_endian == true) {
it.insert_byte(raw_bytes[i]);
} else {
it.insert_byte(raw_bytes[CustomFieldFixedSizeInterface<T>::length() - i - 1]);
}
}
}
// Write num_bits bits using the iterator
template <typename FixedWidthIntegerType,
typename std::enable_if<std::is_pod<FixedWidthIntegerType>::value, int>::type = 0>
void insert(FixedWidthIntegerType value, BitInserter& it, size_t num_bits) const {
ASSERT(num_bits <= (sizeof(FixedWidthIntegerType) * 8));
for (size_t i = 0; i < num_bits / 8; i++) {
if (little_endian == true) {
it.insert_byte(static_cast<uint8_t>(value >> (i * 8)));
} else {
it.insert_byte(static_cast<uint8_t>(value >> (((num_bits / 8) - i - 1) * 8)));
}
}
if (num_bits % 8) {
it.insert_bits(static_cast<uint8_t>(value >> ((num_bits / 8) * 8)), num_bits % 8);
}
}
// Specialized insert that allows inserting enums without casting
template <typename Enum, typename std::enable_if<std::is_enum_v<Enum>, int>::type = 0>
inline void insert(Enum value, BitInserter& it) const {
using enum_type = typename std::underlying_type_t<Enum>;
static_assert(std::is_unsigned_v<enum_type>, "Enum type is signed. Did you forget to specify the enum size?");
insert<enum_type>(static_cast<enum_type>(value), it);
}
// Write a vector of FixedWidthIntegerType using the iterator
template <typename FixedWidthIntegerType>
void insert_vector(const std::vector<FixedWidthIntegerType>& vec, BitInserter& it) const {
static_assert(std::is_pod<FixedWidthIntegerType>::value,
"EndianInserter::insert requires a vector with elements of a fixed-size.");
for (const auto& element : vec) {
insert(element, it);
}
}
};
} // namespace packet
} // namespace bluetooth